I have started this new thread to finish documenting what I am doing to my 1988 Fiero formula. I had initially started trying to do a swap with a 1990 TGP engine on the cheap and documenting it here on PFF at https://www.fiero.nl/forum/F...2/HTML/099797-8.html
After finding a bent rod in the TGP I began to look for some aftermarket replacements, maybe a set of Scat or Eagle steel rods for a small Chevy. The small Chevy rods are not a direct replacement, but there is lot of people on the different 60 Degree among other forums that reference using SBC rods in a 60D engine. I investigated this swap and found it easily doable. I will post the process here in this blog when I modify them. While looking for some steel rods to modify I came across a smoking deal on Ebay for some BME forged aluminum rods for a small Chevy advertised as new and unused. I could not resist the exotica of these rods and bid on them. To my amazement I won the bid at 92.00 $ and 13.95 shipping and handling for a total of 105.95 $ for a seriously whip a$$ set of rods.
I know, I know you can’t use aluminum rods on the street right… Wrong…. you can read about using BME aluminum rods on the street at their website… http://www.bmeltd.com/rods.htm
I bought these rods on Friday and they arrived on the following Wednesday
At first I was disappointed and pissed all at the same time… The packing was horrible, very little bubble wrap and the rods were stacked together in 4s with nothing between them. On first inspection they looked as if they had been set up in a block that had never seen fire, and had some light grease on them. After a good clean up they turned out to be just as advertised, unused, but as I was cleaning the greasy hand prints off I found a crack in one of the eight rods, I’m sure this probably happened on the trip from California to Virginia… Good thing I only need 6 of them, and still have one for spare.
Now all that was left of the TGP short block was the block and crank, the crank would fit nicely in a 3.4 DOHC engine and I could gain some serious HP going to a DOHC architecture. My mind was made up I would ditch the TGP block, keep the crank as it is by far the best crank put into any 60D engine from the factory, the crank specs are below… 981 AWD van casting crank that has been lightened, Nitride coated journals to 60 Rockwell, has rolled and filleted journals and the oil ports have been enlarged and chamfered. The specs were sourced at… http://www.turbograndprix.c...d%20Differences.htm)
There has been allot of work already completed on my TGP thread that will easily move over to this DOHC build these include…
The TGP crank
IshiHara-Johnson crank scraper
Windage tray
Piston Oil spray system mounted to the windage tray
All of these items should fit the DOHC end without any trouble.
I will migrate the pertinent build information and pics for the above items to this thread from the old one soon.
I thought I would post the last entry on my old thread as a trasistion to this new build...
My best efforts to use the factory TGP engine minus the heads and intakes reached a low point when I discovered a bent rod. With the rods needing to be replaced, all that is left of the original TGP engine is the block and the crank. The crank is far superior than any other factory crank put in the 60D engines, but I am also sure the modern 3.4 block is a stronger casting than the high nickel TGP block by nature of it’s beefier castings. This point has been made by a lot of members here on PFF and has not fallen on deaf ears.
I liked the rarity of the TGP and felt it would add some nostalgia to my project, but after finding the bent rod and procuring a set of aluminum rods to replace them with I have decided to upgrade the block and heads to the 3.4 DOHC platform and use the TGP crank and recently acquired aluminum rods for several reasons and are as follows…
Strength of the modern block castings.
The DOHC has no cam galley to interfere with the larger aluminum rods.
1200 $ in cam , lifter and roller rocker cost is now unnecessary.
DOHC 3.4 makes 215 hp before I add the turbo/s vs. the TGP at 205 hp with a turbo.
Boost levels will not need to be so high to attain the desired 350 hp goal.
Modern DOHC architecture and 7000 RPM redline.
I don’t know about you guys, but I will be sad to see the TGP go the way of the buffalo. However I will be moving on to much more advanced engine. I will be able to salvage my crank, the aluminum rods, crank scraper, windage tray and the piston oil spray should still work on this engine. So I haven’t wasted to much time as all of the stuff I have been working on will transfer right over to the DOHC engine.
There are two at the local bone yard right now 129.99 pull your self (not to shabby) that I hope to get to this weekend or next weekend at the very latest. I will be starting a new thread called “Turbo 3.4 DOHC Build”
Thanks for all of the information and support you guys have put into this thread, it has been allot of fun I hope to see you guys on my new thread.
Wish me some luck…
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02:04 PM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I wouldn't do aluminum rods unless you only drag the car for a short running time... and make sure they are forged.... Aluminum expands and contracts a lot!
ARI makes a nice set of H-beam rods that are forge steel but they are a CNCed and they balance in weight. Then go forged aluminum pistons..... I bought a set from Ross. They will custom make them for you at about a bill (100) each. Ari ran about a bill for each too.... they are quality and are worth it.
These were made for a 3.4L P/R and the rods are a stock length to the block. The pistons are .030 over
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02:17 PM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
The OBDII engines have larger ports and higher flow numbers. The '97 engines have smaller diameter lighter valve lifters.
The DOHC is NOT modern or advanced. It is a cobbled together adaptation of pushrod hardware. The implementation of the cam carriers makes the engine MUCH heavier than it should be. It DOES still have a cam tunnel in the block and has a lobeless intermediate shaft going back through the block to drive the oil pump.
My parents live about 2 hours from Richmond. I have a torn down DOHC engine there along with a pair of OBDII cylinder heads and one '96 cam carrier. I'll let those go cheap if you want them.
[This message has been edited by Will (edited 07-17-2009).]
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02:58 PM
Jul 20th, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
The weekend was finally here and the acquisition of a DOHC engine weighed heavily on my mind, but the gods of HP were not looking down on me with any favor as Saturday morning arrived. I was overloaded with menial tasks and the usual family commitments, it looked as if my junkie itch would have to be scratched some other time.
The day started with the repair of a hole the resident squirrel family’s matriarch had chewed in the eave of my roof for the third time, and this time the little bastard shredded a box in my attic containing some of my prized still in the blister pack toy motorcycles that I have been collecting since I was twelve.
Now I’m no tree hugging PETA supporting fascist, but I do what I can do and believe in live and let live, but this insult was too much to bear. It was on !!!
I scrambled down stairs opened the safe grabbed the AR15 and a clip and headed toward the back door when I ran into my 6 six year old who inquisitively asked “Daddy what are you doing ???” Smart girl, the AR will make too much noise, I turned and hurried back to the safe and traded the AR for the bolt action double duce.
By this time my daughter was loaded up and off to learn how to spend too much money with my wife. I set the rifle in the corner and began my work on the roof, keeping an eye out for the illusive house eating Squirrelzilla.
An hour or so later I heard the horrible sound of a disk brake rotor grinding on the rivets of a worn out pad, it was my nephew limping into the driveway looking for some help. I climbed down off the roof and when I down my nephew was already around back telling me his woes when he stopped short to ask about the riffle in the corner. I mumbled a few curses to my self an exclaimed that it was best if he didn’t ask any questions unless he wanted to be incriminated as well.
I put the rifle away, got some tools and set to work on his brakes, it had to be the thinnest, most cracked rotor that I had ever seen. After removing the rotor I found a galled spindle, my mind suddenly deduced that the spindle was an expensive dealer item and that a trip to the junkyard was in order to look at the availability of DOHC… I mean get a spindle “what luck” I excitedly said. Lucky !!! my nephew said how is a bad spindle lucky ??? My mind raced as I searched for the appropriate response… “Lucky the wheel didn’t fall off” I said in the most serious tone I could muster “I have a lot to do today, but Fiero I mean family comes first” I told him.
I called my brother for some back up and began to load the hell box up with tools for the junk yard sortie when Squirrelzilla crossed my mind, the gods have other plans for me today I thought, I’ll get her a$$ another day.
I loaded the truck and my brother arrived in shortly there after. With the truck loaded up we were off to the local one price fits all junkyard.
We arrived at the junkyard about noon.
It looked as if we were in luck the place was almost empty, it looked like we would have the run of the place.
Fortunately GM is the first section in the yard, as it is one long skinny mother.
As we approached the first car in the first row was an Aurora with some pesky interloper tinkering away underneath.
I turned out it was my brother who had gone on ahead of me as I signed us in and paid the sacrificial dollar to enter checking the oil plug for bits of metal.
The Aurora had a 3.5 DOHC engine in it.
A check of the odometer reviled no clue to the mileage as it was a digital readout.
My brother found copious amounts of metal on the plug, no need to use the magnet for a better check. This is exactly what we expected to find. The body of the car had no damage to it, it likely found its way to bone yard via a bad engine or transmission and after investigating it was obvious the engine was the culprit.
We moved farther into the jungle of cars and found another Aurora midway in.
It also sported a 3.5 DOHC engine.
This body of this car also looked ok. A quick check of the plug produced no metal, so we inserted the rope magnet and found no metal on it either. This could possibly be a donor.
This car was equipped with a digital odometer as well so no accurate mileage could be ascertained from it, but a check of the glove box revealed and inspection slip from December of 2008 with 108,000 miles registered on the slip.
We continued deeper into yard and found a Z34 that looked as if it had been rolled with a crushed roof and damaged hood that looked promising.
A quick look under the hood the car had some promise.
It revealed a 3.4 DOHC engine that had a few minor parts removed.
A quick look at the odometer showed the sad truth, 246,000 miles this baby was all whored out, as it turns out a closer look at the car revealed lots of footprints on the hood and windshield. A case of river dance not rollover perpetrated by some testosterone driven teens while broke down in someone’s yard I’m sure.
We pulled a spindle and found an almost new rotor for my nephew’s car and headed out of the yard.
All of this 3.4, 3.5, 3.6 and 3600 engine designation is confusing. Are they all part of the 60D engine family or just some of them and what parts interchange between them, what's the best year and so on. All of this will take some research.
Any one with information on this subject is welcome to chime in.
Thanks for looking.
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11:29 AM
aaronkoch Member
Posts: 1643 From: Spokane, WA Registered: Aug 2003
Iron head motors are 2.8, 3.4 in the 60* pushrod family. When GM went to the newer head design (gen II I believe) they started referring to them as 3100, 3400, 3500, 3900. From what I've seen personally, I believe all the DOHC motors (the 3.4 TDC, the 3.6VVT) are labeled as 3.x with TDC or VVT after it to denote that they're special and more expensive. Like your shortstar, it's a 3.5 DOHC.. But the shortstar isn't the 60* family either..
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11:56 AM
TiredGXP Member
Posts: 712 From: A cold, miserable place Registered: Jan 2008
Iron head motors are 2.8, 3.4 in the 60* pushrod family. When GM went to the newer head design (gen II I believe) they started referring to them as 3100, 3400, 3500, 3900. From what I've seen personally, I believe all the DOHC motors (the 3.4 TDC, the 3.6VVT) are labeled as 3.x with TDC or VVT after it to denote that they're special and more expensive. Like your shortstar, it's a 3.5 DOHC.. But the shortstar isn't the 60* family either..
The Gen 2 aluminum head engines were designated 3.1 MPFI and 3.4 MPFI. These were basically the same Gen 1 block but with provision for a crank position sensor. Valve sizes were the same as the iron head, but the valves were canted to reduce valve shrouding.
When Gen 3 came around, GM started using the 3100, 3400 etc designation for the pushrod engines. Major change to the block was the addition of a third oil gallery and true priority oiling to the main bearings. These blocks also used hydraulic roller cams. Heads had better flow than the Gen 2 engines. Intake valves on the 3400 increased to 1.76 inches (also for the 2001 and later 3100's, I think). 3500 is supposed to have the best flowing heads and intakes of the lot.
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10:25 PM
PFF
System Bot
Jul 21st, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I appreciate the information, I’m pretty familiar with the push rod engines it’s the DOHC engine family that I am curios about.
After some research I see that the 3.4 DOHC is the closest to my TGP stuff, this allows me to reuse the oil spray, windage tray, crank scraper and aluminum rods that were slated for my TGP block.
You mentioned that there is and extra oil galley on the gen 3 engines, the 3.4 DOHC is based on the gen 2 design. Does this mean it does not have the extra oil galley ???
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08:47 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I will be taking one of my rods (the cracked one) to the machine shop tomorrow along with one of the good stock TGP rods to have it narrowed to fit my crank so it can be set up in the block to check to see if it will clear the block castings.
I took some measurements with the stock rod and it looks like they will fit, the only close spot is where the big end of the rod passes the bottom of the bore. This looks tight but I only need to clear it by 100 thousandths to allow for the aluminum to expand. Hopefully it will clear with out modifying the rod.
I will post some pictures when I have all the pieces in place.
Thanks for looking
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03:17 PM
Will Member
Posts: 14249 From: Where you least expect me Registered: Jun 2000
The 3.5 is a 90 degree V6 that isn't really related to anything (although derived from the Northstar & Aurora V8's, it has different bore and stroke than both) and the 3.6 is a clean sheet design that shares zero parts with any of the older 60 degree engines.
The TDC has a cast crank.
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05:21 PM
gt40racer Member
Posts: 75 From: Abu Dhabi, UAE Registered: Mar 2002
One thing for sure is that your posts are very entertaining. I cracked up reading about the squirrel. Keep it up! I admire your determination to do something that hasn't been done before. There is also something to be said for doing something that has already been done. No shame in letting someone else do the homework and experimentation for you. It all depends on your skills, how deep your wallet is and what sort of timeline you are shooting for. Personally I think your choice of the 3.4 DOHC is a good one, it's high revving personality really fits the Fiero, especially with a 5 speed (or 6 spd!). The 96-97 heads have great flow and there is a lot of potential for a turbo application. Matt Hawkins is producing over 400 hp with his mildly built turbocharged 3.4 DOHC. I dynoed my NA 3.4 DOHC and it produced 220 rwhp. I had a local shop build me a custom turbo setup while I was in Iraq and it was just recently completed. I'm still working through some tuning issues with the $8f ODB1, the tune is nowhere near optimum but it produced 285 rwhp on the dyno at 7 psi boost, so 350 hp is a realistic goal. I'll be following this thread and adding my .02 cents if I think I can offer something constructive. Good luck and happy hunting at the salvage yard!
[This message has been edited by gt40racer (edited 07-21-2009).]
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06:03 PM
ricksmastermix Member
Posts: 588 From: Commerce, GA 30529 USA Registered: Nov 2001
Aluminum rods just don't work in street applications, they don't have the durability. If you decide to use them, install a fire suppression system, you will need it.
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10:22 PM
Jul 22nd, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
Thanks for your interest GT, After reading up on the 3.4 DOHC it seems that the short first gear in the Getrag and the strong torque curve of the turbo will propel the engine nicely until the real power comes on above 4000. It should be nasty.
Thanks for your input.
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07:46 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I used to have the same attitude about aluminum rods in a street motor, but after doing some research I found that most people like my self have no experience with aluminum rods on the street and everything I/we know is what we have heard. Check out BME web site. The link is in my first post on this thread. Bill has some aluminum rod on the street claims that are worth looking at. I also spoke with Bill in person as well as allot of others about aluminum on the street and I have been impressed by their claims (suckered in) I’m going to put there claims to the test in a 7000 rpm engine. It should be fun an informative and possibly tragically expensive if it goes wrong.
Wish me luck. Thanks for your interest.
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07:58 AM
imacflier Member
Posts: 946 From: Levittown, NY, USA Registered: Apr 2002
My TGP rods are better than the DOHC rods check out the TGP engine specs at the link I posted in my first post on this thread. Even with the 1037 and quenched caps somebody managed to bend one of these as seen in my TGP thread also linked in this thread. The aluminum was cheap and exotic and adds some level of risk to this build which keeps me interested.
Thanks for your post and your interest
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08:04 AM
sspeedstreet Member
Posts: 2306 From: Santa Maria, CA Registered: Dec 2002
Fatigue life has always been the problem with AL rods. The reason they've worked for 1/4 drag cars is they tear the engines down after every run, allowing inspections. There are only so many load-unload cycles in an aluminum part. If these rods have been used, and the fact that one is cracked suggests they have, there may be no life left in the remaining rods. The only non-destructive way to know if they're used up is when a crack appears.
Steel and aluminum are totally different cats when it comes to fatigue life.
I used to have the same attitude about aluminum rods in a street motor, but after doing some research I found that most people like my self have no experience with aluminum rods on the street and everything I/we know is what we have heard. Check out BME web site. The link is in my first post on this thread. Bill has some aluminum rod on the street claims that are worth looking at. I also spoke with Bill in person as well as allot of others about aluminum on the street and I have been impressed by their claims (suckered in) I’m going to put there claims to the test in a 7000 rpm engine. It should be fun an informative and possibly tragically expensive if it goes wrong.
Wish me luck. Thanks for your interest.
If someone is in the business of making and selling aluminum rods, I expect his opinion to be both biased and suspect. Ask someone who manufactures both.
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03:36 PM
Jul 23rd, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I knew that when I chose to use these rods I would draw a lot of fire from you guys. My decision to use aluminum rods in a street motor has been based on research not speculation. Yes, I would agree listening to aluminum rod manufacturers only would be a problem. I spoke with many aluminum rod manufactures, but I also spoke to a lot of other people on this subject as well. I will not dispute that there is a stigma around aluminum rods, and I know of no one locally with any experience using these rods in anything other than a strip car. I know, there is a reason no one is using these rods on the street right… You can’t use aluminum on the street right… Well I’m going to find out… Contrary to popular belief aluminum rods have been used on the street for over 20 years in Pontiac V8s by several well known and respected engine builders due to the lack of a good steel replacement. Now I’m not going to drive this car every day to work and I live in the south where it is warm most of the year. I would be surprised if I put over 10,000 miles a year on the car. The bottom line is I haven’t heard from anyone here on PFF that have actually used aluminum rods in a street motor. So all of this is pure speculation and innuendo on everyone’s part including me. What I can tell you is that BME’s Bill Miller not only makes these claims on his Website, but has done so in several major publications. The guy has stones, big ones, because everybody who buys a set of rods will be holding his a$$ to that claim and that could be very expensive. One things for sure were all gonna find out here soon enough. On the subject of whether the rods having been used or not is one I can answer. Any rod that has been rotated on a crank, especially an aluminum one will have the tell tale swirling on the journal face of the rods, these have none. It is much more likely that some ham fisted unknowing mechanic chucked it up in a vice to bush it or for what ever reason and cracked it, or it could have been dropped (see the pics in my next post I went to the machine shop yesterday) and the way it made its trip from the west coast to the east in the poor packing wasn’t to easy either.
Thanks for all of your input, it has not fallen on deaf ears, but doing stuff that other people say can’t be done is half the fun.
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09:12 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I’ve posted this in another thread but here are some excerpts from the BME site. Urban legends abound in the gearhead community. One is: aluminum connecting rods don't work in street engines. Prior to the mid-'70s, that might have been true, however, introduction of the Bill Miller Engineering Forged Aluminum Connecting Rod in 1975 provided an exception to that myth. The BME Rod has good durability in high-end, high-power, street/strip or hot street engines because it is die-forged, rather than cut out of an aluminum plate. Bill Miller Engineering's unique, high-strength, aluminum alloy further enhances fatigue strength such that the potential durability of BME Rod rivals that of many forged steel rods and exceeds that of a few. About 20 years ago, a few resourceful engine builders, led by H-O Racing's, Ken Crocie, began using BME Rods in very-high-performance street engines. Crocie, a racing and street/strip Pontiac V8 specialist, faced with a shortage of acceptable steel rods for Pontiacs, began to use BME Aluminum Rods. While a few other engine builders have followed Crocie's lead, admittedly, use of the Bill MIller Engineering Rod in street engines has not been widespread, but that's only because of its higher cost and the stubborn belief that any aluminum rod is unsuitable for street use. "In a street application, using the aluminum rod is a no brainer," BME President, Bill Miller recently said in an interview with an automotive magazine. "I don't know exactly how the myth that aluminum rods can't be used on the street got started, but I'll guess that early manufacturers of aluminum rods, back in the 60s and early-70s, weren't making them using the forging process we're using. With the material we've got and they way we manufacture the connecting rods, they'll live a couple hundred thousand miles on the street because a street application is, for the most part, low load. You gotta understand, our basic Aluminum Rod is made for 10,000 rpm and 800-hp. The design criteria for the connecting rod is way overkill for what it's gonna see on the street. We been running aluminum rods on the street for 20 years." More of this can be seen at:
I got started in earnest yesterday with finding out if I will be able to fit these rods in the tightly packed 60D block. I am using the TGP block as my test bed, it should almost identical in the critical clearance areas, but there are no guarantees until I acquire a DOHC block. Hopefully this weekend. I called my regularly used machine shop, and they were swamped with race season hardware. We have a mill and a lathe in the shop that we recently acquired but we have not wired them to the phase converter yet. So I called another reputable shop and they said to bring them down so off I went. I only took the cracked rod to be machined down to fit the journal for test fitting, no point in paying for something I can’t use and there is no hurting this cracked rod.
I arrived at Ballos Precision Machine after lunch.
I promised you guys some pics of the rod with the crack so here it is…
You can see the crack at the top part of the picture just to the right of the pin hole, it shows up as a black line, also notice the flat spot on the rounded part of the rod, some one dropped this baby, also notice the dent is opposite of the crack. Now it is hard to tell anything about this crack from the picture, but I can tell you it is so shallow it could be buffed out. Even as shallow it is, I do not trust it.
Here is a Full view of the rod.
I spoke with the head machinist for over an hour, very nice and informative. He wants to see what happens with these rods on the street as well. I will get the rod back today and post up when I have bolted it up to the crank with all the gory details.
Thanks for looking.
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11:06 AM
sspeedstreet Member
Posts: 2306 From: Santa Maria, CA Registered: Dec 2002
He wants to see what happens with these rods on the street as well.
Thanks for looking.
I'm anxious to see how it works out as well. Not trying to talk you out of it, I'm just relating some of my materials engineering background
The old line about AL rods not "working" in a street motor is ridiculous. They'll "work" like hell until they fail.
~Neil
BTW, that crack is a classic fatigue failure. It might be a stress crack from the forging process, but either way, if the other seven rods are from the same manufacturing batch, I'd be leery.
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01:21 PM
Jul 24th, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
With my mind wrapped around sugar plums and aluminum rods I planned on getting out of work a little early, but just as I was ready to leave my phone lit up like a Christmas tree and instead of leaving early, I left 20 minutes late. I rolled out of work in a hurry to beat the local traffic and get to Ballos before they closed.
After battling the local blue hair militia, and space cadets doing 50 in the hammer lane for position I arrived at Ballos just as they were locking the door what luck !
I scrambled up the stairs, Stewart opened to door for me and said “I didn’t think you were gonna make it” He pointed to the counter where my stuff was sitting and began to give me some details on the job. The actual width of the stock rod was .0846 and the aluminum rod came in at .0911 for a total of 65 thousandths that he removed from both sides of the rod. He also pressed the pin out of the stock rod, after measuring the pin hole he suggested that the piston hole size should be enlarged rather than a bushing put in the rod due to the small difference in size (the bushing would be wicked thin) he would upgrade the pin to a small Chevy pin.
I dove to the shop in heavy traffic, but time was no longer a factor. When I got there I did a little comparison between the two rods laying them side by side. This was the first time I had one of the TGP in hand with out a piston attached.
I then laid the steel rod over the aluminum to get a sense of how much bigger the aluminum rod was than the TGP unit.
I was shocked at how close they were on the big end. The aluminum was slightly larger in a few places on the big end but I could not get it to show well in the pics I took.
He did a quality job narrowing the rod up for me, I was well pleased.
I laid my stuff out and began to lube up the parts and figure out how I was going to fake a pin for the clearance test.
I dug through the junk bin and came up with and alternator spacer that would do the job filling in as a temporary pin.
It was a little long so I cut it down with the ban saw.
I test fitted the piston, it had good articulation, but I was worried that the beam of the rod being so thick was going to interfere with the bottom of the bore.
With the rod test fitted with the piston, I took the rod cap off, lubed it up and was ready to place the assembly in the block.
And this is where my first problem occurred, I had expected trouble, but this caught me by surprise.
Now it’s not as bad as it looks in the picture, but I could not capture a better picture. It should fit no problem in the 3.4 bore. After all this effort I wanted to see this puppy in the block so I could check the clearances in the block, so took the mains off to insert the assembly from the bottom.
With the crank removed, I slid the assembly in and snugged up the cap. Man did that rod look sexy sitting the block. I was starting to get wood. I wiped the drool from my chin and began to rotate the crank.
I brought it around to the long side of the stroke and checked the clearance of the rod. 250 thousandths clear. I only needed 100 thousandths to allow for the aluminum rod to expand, plenty of room. So far so good.
I rotated the crank on around and as the big end of the rod came around on the piston hole and stopped, this did not surprise me, as I mentioned earlier in this thread the clearance on the stock rod was tight here.
I brought the rod back around and marked with a sharpie and spun the crank back to where the rod had made contact to look for the contact point.
To my surprise and again pictures do not give a good likeness to what I see with my eyes, was that the rod was hitting the very bottom corner of the rod just on the edge, but just barely. I could probably knock it down with a file there is so little material touching.
With my time waning I remover the piston and rod to try it in the other bores for clearance purposes. But due to the block design of the 60D I could not slide the piston in any of the other holes from the bottom.
I am almost positive that the 3.4 bore size will eliminate any of the clearance problems I am having in the 3.1 TGP block. So I now desperately need to acquire a 3.4 DOHC block to finish my testing, but so far everything seems to be OK. I have a line on a few engines and whole cars on Craigslist and will be investigating them this weekend.
As for the small Chevy rod swap goes, it is true, a set of steel rods from a small Chevy with a 2 inch journal will work with a little narrowing at the machine shop.
Thanks for looking.
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11:14 AM
Jul 25th, 2009
gt40racer Member
Posts: 75 From: Abu Dhabi, UAE Registered: Mar 2002
You really need to get a 3.4 block for testing, they have so much more webbing the the POS 2.8/3.1 blocks(yes even the TGP block is a POS next to a 3.4), the bigger bore may help and/or the webbing may interfer.
Here is a thought about aluminum, with the oil spray, could it cause it to shrink/expand at different places where the oil spray hits? food for thought
Yes, I definitely need a DOHC block to get this project back on a roll. I am thinking that the rods will fit in the DOHC block with little or no problem, I could probably polish the casting marks off and get the rod to slide into the 3.1 bore and the tight spot on the 3.1 block hits just on the very edge of the bore, which should be larger in the 3.4 The difference in the size of the big end is minimal between the steel and aluminum rods and only needs a pinch to fit, I could have sanded the rod and made it fit, notice I said sand not grind The bracing in the 3.4 block is a potential problem, I feel it will be ok, but without one in hand we will have to wait and see.
Thanks for the heads up.
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10:13 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
I considered the oil spray and aluminum rods a potential problem as well, but after speaking to the machine shop, 80 % the shrink and swell of the aluminum happens during the start up and cool down of the engine and should pose no problem once the engine has warmed up. The one warning Bill Miller gave was to allow the engine to warm up completely before driving. The reason for this is the large amount of shrink and swell at the rod bearings during warm up. He said that this was of great importance especially in the winter when this phenomenon is at its greatest, thus the reason for the aluminum rods greater bearing clearance. Truthfully I am stoked about using the aluminum rods for this project, regardless of the outcome, after some investigation and some testimonials I have decided to use a lighter flywheel as well (not to light) with this engine to try and get it to that 4000 and above RPM range where the engine really starts to make power.
I have been getting the run around on a 93 z34 w/ 5speed and 137,000 on the ODO They were asking a 1000 $ for the car, it runs for about 5 minutes and then dies, let it sit for 30 minutes and it will do it all over again ??? I’m sure there is nothing wrong with the engine itself so I offered 500 $ and they said they would sell it for that, but have not contacted me back yet.
Hopefully this will come through.
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10:32 AM
KurtAKX Member
Posts: 4008 From: West Bloomfield, MI Registered: Feb 2002
They were asking a 1000 $ for the car, it runs for about 5 minutes and then dies, let it sit for 30 minutes and it will do it all over again ???
I'd be very willing to bet a small sum of money that the problem is the crankshaft position sensor down on the side of the block. I would assume you've got at least one spare if you've got a TGP block.
Just don't tell the seller that its 5 minute / 1 bolt / $20 fix.
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01:42 PM
Jul 28th, 2009
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
In the upper right corner of each posting there's little 'profile link' use that to get his e-mail contact. The number he gave is the zip-code for shipping origin.