I'm strengthening the stock motor for added durability under boost and hopefully increased longevity over the current motor. Forged LS1 pistons, forged H-beam small journal 5.7" rods narrowed (stock rods are 5.827" for my engine in case anyone is wondering about the modification), and forged 3900 crank offset ground to 3.43" stroke (corrected now to the intended 3.56 stroke). The crank is slightly more than a pound lighter after the regrind and all of the remaining parts are considerably lighter than the stock parts they are replacing. The assembly may end up lighter still once it is balanced. The camshaft has been reground for more duration and a tighter LSA than the stock cam and the resulting combination should yield about an 11.5:1 compression ratio with an intended 10 psi boost minimum on premium fuel if necessary. It sounds impractical however, my current testing along with two examples I've read about with high compression and boost suggest it is more than just possible with the anti-detonation measures that will be in place. The high compression is also intended to increase efficiency and hopefully maximize fuel economy as well as offline performance. 11.3:1 compression and 8.5 psi boost example: http://www.da-motorsport.co...jeler/mz3/mz3_en.htm
I'm getting rid of the twin turbo setup. The stock manifold system probably flows as well as any header system I could install on it and will certainly be more durable. T-67 turbo.
Offset ground crank to 3.43" stroke (by mistake, this crank was not installed as indicated later in this thread). I made what I hope is a minor mistake, I installed the crank with the tag on it and the ends of the twist wire found their way just beneath the journal right on the bearing. I tightened the cap and realized there was a problem when the crank wouldn't move. I'll inspect the crank later to see if I scarred the journal, the wire flattened like plastigage so I'm hoping any impression present is in the bearing. It's fine.
The pistons have a 9cc volume vs. the stock 18 cc. I'll be installing the camshaft and checking clearance with the cam advanced and retarded to see if notching will be required. I plan to limit the cam to about 10 degrees of advance and retarding it around 3500 rpm to the recommended install angle for the camshaft.
So far so good, the piston sits just below the deck. I thought modification of the connecting rod was going to be needed when I encountered interference while trying to rotate the crank, fortunately the problem was the bolt to the oil squirter I had removed previously and had not screwed in flush. After I removed it there was no problem, didn't have room to tighten it down without removing the crank.
[This message has been edited by Joseph Upson (edited 11-14-2010).]
Have you ever successfully pressed the older (3400-style) "7X" wheel onto the crankshaft to be used with the older OBD2 and OBD1 stuff? Do you know of anyone who has?
Originally posted by sardonyx247: I think that high of compression ratio and boost is a bad idea. Good luck to you.
I expect doubt and have in the past expressed some of my own regarding plans for advances that have not been demonstrated because of beliefs that for the most part are rooted in what couldn't or shouldn't be attempted according to outdated technology limitations (iron heads and early combustion science). More than ten years ago practically everyone would agree with you and many would have said the same thing about being able to run this engine on the 87 octane fuel it's rated for with its stock 9.8:1 compression ratio and even moreso the 3.6L DOHC non direct injected engine with 10.2:1 compression and an 87 octane fuel rating.
My rational is based on the fact that I currently run near 10:1 compression, with 8 psi at 212 degree inlet temps before it was intercooled on a lousy Turbo Grand Prix tune with an advanced TGP spark table that was for an engine with an 8ish:1 compression ratio that resulted in 0 degrees retard. With that being noted, Intercooling, oil cooling for the spray on the pistons, water/meth injection, 93 octane fuel, and HD radiator for ~180 deg max engine temps should be plenty of anti-detonation measure to accomodate the compression and boost increase on an engine that doesn't have a detonation problem in its current state except for a 1 degree logged retard after changing the cam position and not properly adjusting the fuel table. If I'm not mistaken all of GMs turbo cars and probably the SC cars as well now have a static compression of at least 9:1 and run at least 7 or more psi of boost and they usually incorporate abuse friendly tuning with room to spare. Even if I'm some how limited to the same boost level the end result will still be more efficient and more powerful than it is currently, but I'm very confident and certain it will work as planned and change a lot of minds about combining high compression with boost.
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Originally posted by KurtAKX: What are you doing for engine management? Have you ever successfully pressed the older (3400-style) "7X" wheel onto the crankshaft to be used with the older OBD2 and OBD1 stuff? Do you know of anyone who has?
The car is driveable right now except for a bad gear select cable. The engine is being mocked up for measurement and clearance purposes using a second motor.
I think that high of compression ratio and boost is a bad idea. Good luck to you.
The only thing that high compression does is lower the target boost pressure... which in turn lowers the efficency of MOST turbos out there.
In this case, the T67 should preform well at the 14-16psi that he will be running at about 500hp. I am tuning a LS1 with stock compression to 8psi again today with a T67. Last one I did made 485 to the wheels.
Originally posted by KurtAKX: Have you ever successfully pressed the older (3400-style) "7X" wheel onto the crankshaft to be used with the older OBD2 and OBD1 stuff? Do you know of anyone who has?
I was sure I had seen it done somewhere, but I couldn't remember where...I thought it was americasfuture2k's car but I struck out there.
So you use heat (propane or acetylene or an oven I'm assuming) to get the ring on, but how did you get it off the 3400 or 3100 crank in the first place? Heat?
I have a LX9 just chillin' in the garage, and I really prefer the protection and OE integrity of the crank sensor being in the crankcase, and I want to do this as well. Any tips?
I was sure I had seen it done somewhere, but I couldn't remember where...I thought it was americasfuture2k's car but I struck out there.
So you use heat (propane or acetylene or an oven I'm assuming) to get the ring on, but how did you get it off the 3400 or 3100 crank in the first place? Heat?
I have a LX9 just chillin' in the garage, and I really prefer the protection and OE integrity of the crank sensor being in the crankcase, and I want to do this as well. Any tips?
Only the late model engines come with removable trigger wheels and none to my knowledge are 7x, I had some custom made and hopefully will have another batch available soon. Yes the ring was heated and installed, for added sense of security I also installed a couple of set screws though it didn't appear they were necessary.
[This message has been edited by Joseph Upson (edited 04-10-2010).]
Finally got around to checking valve to piston clearance today only to find at the end it's worthless as the machinist did not do what I explained I wanted done to the crank.
He did an excellent job of radiusing the crank in place of the stock undercut (clue #1), unfortunately that radius creeped into the bearing surface which pinched the wider chevy 2.00" bearing. The 3400 bearing works but is not quite centered. No problem, there maybe chevy race options that are narrower or I can have a custom set made.
Back to the radius. If you explain that you want a 2.25" journal, offset to 2.00" and that you have ~.125" to work with and that you want the metal cut from the bottom of the pin so that the stroke increases outward by .125 minus cleanup, and don't cut the top of the pin except to clean it up, I would hope one would understand that the top of the pin is not to be cut except minutely where necessary. This means that you can't possibly radius the entire diameter of the under cut stress area unless you weld first or cut considerably below the desired stroke.
I explained all the above after saying I wanted it stroked to 3.43 so he would understand I didn't mean .012"/2= .006" above and below to get 3.43, but a full .125" shift outward. I explained stock rods are 5.827 and showed him the 5.7 rod they were being replaced with so he could make a mental comparison.
Now I have to wait until Monday to contact him to see if we can't work something out. Now I know no matter how competent the machinist is, from now on I'll be providing connect the dot easy drawings and ABC explanations.
As it stands the piston bolted down sits .096 below the deck at TDC plus the head gaskets ~.064 so it's a safe bet he didn't weld anything. I'll find out what went down when I get in touch with him.
Let this be a lesson to those having machine work performed for this engine involving an offset grind. Draw it on paper with big numbers and no room for excuses.
It's closing in on time for me to pick up where I left off. After more research I've decided to follow the original plan for the 3.56" stroke and high compression boost. I nearly went ahead with the crank that was ground to the wrong stroke 3.43". It would have worked and kept my compression ratio at the same stock 9.8:1 miraculously, but as I said, I researched and although modern technology and engine design has allowed for some amazing accomplishments, I couldn't bring myself to settle for a .142" quinch area although stock is not in the ideal quinch area at .082". GM refers to the head design as "Mist Quinch" despite the gap so it still does what it's suppose to.
I plan to drop the crank off tomorrow if the price is right with a different machinist. I got ahold of another low mileage complete motor for quite a deal being unable to find a crank alone. I'll provide written instructions this time to make it impossible to screw up the job except for deliberate or incompatence.
This is not my drawing, I believe I got it from Keith Black pistons site.
I found this little polishing kit for a good price also at Harbor Freight complete with arbor so that I can work on the exhaust ports for better flow since they are the same size as the 3500 ports according to Sappy on the 60 degree forum.
I'm going to forgo the head and main studs because as I said I've been researching. The multi layer steel gasket is superior to any of the previous composite design gaskets and have a spring like compensation to address cylinder head lifting under boost and high compression applications. They also result in little to no deck/bore distortion in comparison to composite gaskets. It was also stated that the spring like character of the gasket design is most effective when used with torque to yield head bolts which is what GM uses on this motor. As for the mains, the later model engines have stronger main caps than the earlier engines along with the cross bolts through the side of the oil pan for added stability by eliminating cap walk if that even occurs in the 60 degree power plant.
I'm expecting a substantial improvement in overall efficiency and throttle response and will tune for a daily driven ~11.5:1 compression, 8 psi and pump gas. After that is dialed in I'll add the water/meth injection with pre and post turbo nozzles and push towards 15 psi. Sounds like a stretch but I've done quite a bit of reading and given what the engine has accomplished already with its current compression on midgrade fuel it should be no problem at all as there is room for much more than 8 psi on pump gas in its current state.
Polished chambers.
[This message has been edited by Joseph Upson (edited 11-11-2010).]
Originally posted by darkhorizon: Would be a much better solution vs meth injection in my opinion. You would get some stellar gas mileage with that setup.
I'll keep that in mind. My goal economy wise is greater than 30 mpg. The 6 speed should keep rpm at 2000 at 70 mph, engine torque is higher with the cam advanced about 10 deg compared to its install angle, it'll be retarded to install specs at about 3500 rpm for top end power. It did pretty well with the cam overly advanced although it might have produced more low end torque had it been advanced 10 deg instead of the 20 I measured. I hope to find out here soon. I imagine the compression increase alone is good for about 6% improvement in efficiency.
Would be a much better solution vs meth injection in my opinion. You would get some stellar gas mileage with that setup.
You're not talking about stellar gas mileage on E85?
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Originally posted by Joseph Upson:
Back to the radius. If you explain that you want a 2.25" journal, offset to 2.00" and that you have ~.125" to work with and that you want the metal cut from the bottom of the pin so that the stroke increases outward by .125 minus cleanup, and don't cut the top of the pin except to clean it up, I would hope one would understand that the top of the pin is not to be cut except minutely where necessary. This means that you can't possibly radius the entire diameter of the under cut stress area unless you weld first or cut considerably below the desired stroke.
I explained all the above after saying I wanted it stroked to 3.43 so he would understand I didn't mean .012"/2= .006" above and below to get 3.43, but a full .125" shift outward. I explained stock rods are 5.827 and showed him the 5.7 rod they were being replaced with so he could make a mental comparison.
Did you actually tell him "offset grind to 3.43 stroke", right? Your directions above aren't exactly intelligible.
Not the first time a misunderstanding shop has scrapped a crank. Ask me how I know. Won't be the last.
I did a test fit of the Deka 60 lb/hr injectors, I'll have to trim the rail mount bosses on the intake to allow the rail to sit lower and the injectors to fit properly in the seats. I also noticed as can be seen in the picture above that some unshrowding of the injector ports is in order. If you look closely you can see the area of the intake port that is being sprayed by fuel, it has no carbon build up on it. There's also a similar area on the intake manifold in the injector port. The stock injector has two spray passages, the 60s have four for a more conical spary stream so opening up the port should be a good move.
[This message has been edited by Joseph Upson (edited 11-03-2010).]
You might want to give your instructions in writing. It is very easy for a machine shop person to forget what was verbally told to them. They can get interrupted a lot during the work day. You gave at least 6 instructions verbally. People have trouble remembering more than two instructions.
It is your parts. I would not want a misunderstanding to to cost me my parts. Just my $0.02.
Originally posted by Joseph Upson: and forged 3900 crank offset ground to 3.43" stroke.
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Originally posted by Joseph Upson: Back to the radius. If you explain that you want a 2.25" journal, offset to 2.00" and that you have ~.125" to work with and that you want the metal cut from the bottom of the pin so that the stroke increases outward by .125 minus cleanup, and don't cut the top of the pin except to clean it up,
I explained all the above after saying I wanted it stroked to 3.43 so he would understand I didn't mean .012"/2= .006" above and below to get 3.43, but a full .125" shift outward. I explained stock rods are 5.827 and showed him the 5.7 rod they were being replaced with so he could make a mental comparison.
This makes NO sense.
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Originally posted by Joseph Upson: After more research I've decided to follow the original plan for the 3.56" stroke and high compression boost. I nearly went ahead with the crank that was ground to the wrong stroke 3.43".
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Originally posted by Joseph Upson: None the less the desired stroke in the brief above cleary indicates 3.56 stroke.
It was never obvious AT ALL to US that you wanted a 3.56" stroke. I can't imagine it was any clearer to the machinist. If you did not tell the machinist that you wanted him to "offset grind the crank to x.xxx stroke, finish with 2.000 journal for a small block chevy bearing", then you might as well have been speaking Urdu or Pashto to him, as he really (obviously, in retrospect) had no idea what you're talking about. As the guy to whom you're going to get things done, he believes he would lose face if he said he didn't understand and asked you.
(I'll never understand that attitude. Some people seem like they'd rather deliver a bad product and lose business than ask a simple question.)
Anyway, I see equal parts blame all around. I hope your next one goes better. Remember that detailed instructions in the WRONG LANGUAGE don't do any good. FYI, the language your instructions need to be in is NOT English, it's MACHINIST!
[This message has been edited by Will (edited 09-22-2010).]
Originally posted by Joseph Upson: I stated clearly not to remove metal from the top of the pin. We did agree on a clean up trim of about .003-.004" off the top for finishing. I stated I wanted a half stroke increase outward of .125" or as close as possible. I then stated that I wanted the maximum stroke I could get maintaining a chevy 2.00 crank pin journal. I stated they should remove the metal from the bottom of the crank pin ~.250". I again stated not take metal off the top of the pin except for the .00X" as needed.
This is NOT speaking machinist. If you told me this, *I* would have no idea what to do with your crankshaft. I would ask, of course, and if I didn't get anything better than this, it would sit on my shelf until I got instructions that read "offset grind to x.xxx stroke with journals for small block Chevy". If I set it up and found that I need a putting-on tool, I'd call you back and tell you "you didn't give me enough metal".
What do you want the CRITICAL DIMENSIONS of the FINAL PART to be? On a crankshaft with the modifications you want, these are stroke, journal diameter and journal width. You tell him "I want x.xxx stroke, with journals for small journal Chevy bearings". Figuring out how much metal to cut is HIS job. Don't try to do his job for him, as you clearly don't know how, AND that's what you're paying him for anyway.
If you tell him you want 3.56" stroke and he delivers 3.43" stroke, THEN you can blame him.
For example, if you tell your barber to "take it all off the top", do you think he will shave you bald, give you a crew cut, or only trim hair only on the top of your head? If you tell him "#2 on the top, #1 on the sides, fade it at the temple, skin around the ears" you'll get a much more predictable result. But you have to give instructions in the right language.
[This message has been edited by Will (edited 09-22-2010).]
I'm going to side with joseph on this one. If it's not a chevy 350 machine shops don't want anything to do with it. I took my 3900 in for a cam and spring swap with all parts supplied and he told me the pushrods were the wrong length. I asked him what length I needed and while he was measuring I emailed sappy about the problem and he told me what length he ordered. The machinists measurements were the same as sappy's measurements so I picked up the engine. As close as I could tell with my stanley tape measure they were the right length so I installed them. The lifters preloaded good and the engine now runs fine yet the guy told me they were the wrong length. Needless to say I was pissed. I called him and questioned him but he just gave me the runaround without admitting his failure. Good luck Joseph!
Believe me, I've had machine shop experiences. I've had a shop (almost exclusively Chevies) do a crappy job honing my Northstar block. I put an engine together in that block that burned 2 quarts of oil in 100 miles. I've had a *good* shop scrap a crank due to inadequate direction on my part. Of course what I asked for on the crank was breaking new ground all around, so I didn't at that time know how to ask for it and the shop didn't have the clairvoyance to know what I wanted done.
I think that speaking machinist to a machinist will leave him with much less ambiguity about what you want. As I said, if I were a machinist and you told me what you posted here, I'd have no idea what you wanted. I could mill a flat 0.125 deep on the "bottom" (whatever that is) of your crank pins and be following the directions as written.
You also mentioned that both of you wrote down the number, but you also say that you gave the crank to someone who didn't take notes. Your story still isn't making sense.
As I've told other people, having a GOOD RELATIONSHIP with your machine shop is paramount. There are several shops within 1/2 hour drive of where I assembled my Northstar, but I chose one 1:15 away because I was able to establish a good rapport with him and he understood what I wanted. In the strictest sense the closer shops *could* do the work... they had the right equipment and knowledge. However, I'd *still* be collecting parts because what I wanted and the parts I would have given them were things they'd never worked with before.
[This message has been edited by Will (edited 09-23-2010).]
What's that going to do to the geometry of your final build? (IE, piston deck & quench more than compression)
Also, machinists use a minimum of 3 decimal places. Saying that the stroke is 3.29 when it should be 3.31 sounds like a pretty big mistake. Saying that the crank is 3.297 when it should be 3.307 uses the same numbers, but is half the mistake.
I picked up "Will" the crank today and it appears it was ground correctly. I have to add that I received a third phone call indirectly indicating they made a mistake in their measurement of the crank meaning it really was 3.31 on the stroke. They offset it to 3.555. A mock up using the stock piston produced a deck clearance of .040. The end result should be a 4.189 litre.
I finally got the short block assembled. I encountered several delays due to parts preparation and clearances. The LS1 rings turned out to be file fit I discovered at the last moment. The connecting rods were not exactly fully preped requiring a little more clearance on the pin end.
GM runs a .006" top ring gap stock and that's what I measured. I installed the LS1 slugs at the recommended ~.016"
The connecting rod bearing clearance range is pretty tight also with a minimum of .0007". Optimum according to tests is .0024" but I opted for .0015" so I had to search out .001 under bearings as .0024" is the upper limit spec and I didn't want to start at that. According to my research the tighter clearance will add about 18 deg more heat to the bearing temperature but raise the oil pressure a bit by reducing the oil flow past the bearing by about 1 gal/min.
I encountered interference from the 7x crank trigger wheel with the bottom side of pistons 3 and 4 which had to be clearanced. For anyone considering this path in the future 6" rods would be the way to go to avoid this.
Although the specs are pretty much the same for the non VVT motors I discovered something very important for those tempted to use the earlier engine main bearings instead of the late design. In the picture below is a year 2000 bearing on the right next to the stock bearing from the engine. Note the groove in the stock bearing goes 180 degrees while the older bearing tapers off pretty early. That can have a considerable effect on oil pressure duration on the bearings. It may seem like a simple upgrade but when you take into account the cam module which continuously bleeds oil pressure and then the oil squirters I'm curious as to whether or not the change is a necessity as it provides continuous pressure to the crank port for more than 180 degrees as the oil passage eclipses the groove before 0 degrees and beyond 180 degrees of the upper bearing. So it maybe an upgrade for the older engines but essential for the 3900. Only one part store lists the older bearings for the 3900, I believe it's Advance, NAPA lists only the newer bearings for it and they run a little over $100 for the set.
Contact point.
Forged LS1 pistons installed.
Bearing upper half comparison.
[This message has been edited by Joseph Upson (edited 11-04-2010).]
I finally got the engine installed with hopes of starting it today. I'm a little concerned about a small thumping like sound heard while cranking the engine over with the starter before installing it. It sounds like a small spec of weld spatter on a ring gear tooth coming around and being hit by the starter gear. I'm hoping that's all it is or something else less serious. I made sure I didn't have any interference after clearancing the two pistons so that shouldn't be the culprit. I'll find out once the engine is running.
I had to ditch the idea of maintaining a little VVT function since my valve to piston clearance was too close. So close that even with the cam sprocket retarded one gear tooth (did this in an effort to help move the cam closer to its proper install height before spacing the module) there was probably .000" clearance. I read that the exhaust valve is most crucial in this area and that some racers run intake valve clearances as close as .045 with strong springs and care not to float the valves. I aimed for the recommended .080, the exhaust valve already has greater than .100. I used an extra head without the gasket to accomplish the task, this causes the valve to contact the piston at a point earlier than it would with the gasket in place giving me radius clearance, I also put a little over hang on the sand paper disc I cut out to add to that radius. I used adhesive backed sanding discs.
My entire rotating assembly including the flywheel has lost about 13-14 lbs over the previous stock rotating assembly wt. On top of that the compression ratio is about 2 points higher and there is just shy of .3 more litres of displacement and a proper cam placement. Although I didn't take the time to video it, the brief test drive of the upgraded single turbo setup on the stock motor peformed noticeably better although the cam was still advanced.
Hopefully there are no problems with the install so that I can test it and post some respectable results.
Compression test results:
1. 220 2. 230 3. 220 4. 255 5. 240 6. 250
[This message has been edited by Joseph Upson (edited 11-11-2010).]
My PT6776 is making a clean 750hp or more right now.. You sure do have some potential here if you have the octane.
I may suggest for your entertainment to run a few tanks of pure race gas through, the 116+octane kind for the first few tanks. It helps you get a feel for tuning without any chances of leaning out / timing issues causing detonation/knock. That and once you get it tuned in perfect, you can light up to whatever HP level you want without fear.
My PT6776 is making a clean 750hp or more right now.. You sure do have some potential here if you have the octane.
I may suggest for your entertainment to run a few tanks of pure race gas through, the 116+octane kind for the first few tanks. It helps you get a feel for tuning without any chances of leaning out / timing issues causing detonation/knock. That and once you get it tuned in perfect, you can light up to whatever HP level you want without fear.
I don't want to take any chances here. I installed a 4 psi spring in place of the 7 psi spring in the wastegate. Then I'm going to install the Fiero vacuum can (which has a check valve in it) in line with a vacuum feed to the top signal port on the wastegate to pull and hold the wastegate valve open and hold it open long enough with the vacuum reserve from the can to go wide open throttle without boost.
I've also switched over to code59 which has excellent tuning aids like the cell follower that shows you what cell you're in on the Fuel Map, Spark table and others. Then there's Autotune which will chewup my datalog and spit out a recommended fuel MAP. Right now I'm just anxious to get to the point where I can attempt to start it which is about 2 hrs out.
It runs! With all of the last minute adjustments that I needed to make and oddities, I was just a tad apprehensive about it starting up without a problem, but it fired on the first few revolutions.
I didn't hear any unusual noises and suspect the little noise I mentioned when cranking the engine before install is something on one of the ring gear teeth possibly a spec from welding. I only ran it for about 3-4 minutes since it was dark out and I didn't have my laptop connected to fix the stall without a little throttle since I took away a little more than half of the base pulse constant on an estimate, having swapped out the 30 lb/hr injectors for 60s. I did rev it some and it does appear to spin up quicker. So far there is only a small oil leak from the oil drain tube at the turbo.
I have a litany of small tasks to complete on the car which I'll have to assign days to address. First up is calibrating the speedometer using my Dakota digital module. Since Code59 was written for a DRAC module I can no longer address speedometer calibration through the code. I'd also like to have the digital cruise installed.
I'll do a long run-in tomorrow to let things heat up and note any problems that might not be present during short runs. Then I'll start test driving to work on a stable enough tune to take on some long distance testdrives. I don't plan to work on getting video after it's running decent.
Hardened pushrods to go with the reground cam and upgrade to LS6 valve springs.
Finally installed the oil filter in a more practical location.
Heat shield between the turbo and trunk. Two layers of heat wrap strips wrapped in aluminum foil then in thin gauge aluminum sheet metal.
Stroke increase to 3.555, displacement 4.2L Compression ratio from 9.8 to 11.7:1. Rotating assembly weight loss including flywheel and clutch disc; ~10 lbs +/- 1.
Pending install after baseline fluid temps and performance determined:
