Originally posted by Fierobsessed: I'm working on getting the bottom end parts all together. I still have to do yet another machining operation on the rods, I have to narrow the small end of the rods to fit inside the pistons better. And, I need to make a reluctor ring that fits the crank with the 7 timing notches.
BCC makes an internal ring for the 3500, might save you some time and energy.
Been a while since an update. I haven't had a moment to spare till today. So I was working frantically to get as much done today as I could.
First thing, As ericjon262 pointed out, I went ahead and purchaced the 7X reluctor kit from British Car Conversions.
I went ahead and removed the old Reluctor...
I heated up the new reluctor and put it into position.
This afternoon, I also removed the damaged engine.
Tomorrow, I'm hoping to peel the engine off of the cradle, get it on the stand and tear it down. I need to find out what failed. I'm positive that a rod bearing has failed. And I believe that short lube trough on the main bearings may be the bulk of the cause. Joseph Upson found the bearing change in this post> https://www.fiero.nl/forum/F...HTML/107886.html#p28 that the main bearings design was revised sometime relatively recently. Now, practically all aftermarket bearings share the longer trough design. Even when you order them for your '85 2.8 Fiero, you'll get the same "7242MA" bearings that I ordered with the long troughs.
I believe I may have exceeded how much boost a crate engine can handle. Surprisingly, no rod bearing failures had occurred at all, no broken pistons, no real carnage.
I have a feeling that this may have been a result of ring butting. I doubt it was weakness with the rods, but I can't quite rule that out either. I was pushing a lot of horsepower through this engine. The only rods that were severely bent were #1 and #2.
Originally posted by Fierobsessed: It wasn't the power that broke it surprisingly.
along with the pics of the rods and the fuel cut shenanigans the ECU was undergoing..
That looks like fuel hydro lock or miss timing detonation...given the backfire(s) you described at the moment of failure, I'd perhaps go with fuel hydro lock, and not detonation, as your bearings are good and your piston tops from what I can tell look quite intact. The stock LQ1 pistons are the first weakest link in the rotating assembly chain. If the rod was fatigued due to continuous overstress it would have probably snapped under this "event" instead of deflect as it did.
I've never seen a bent rod in a turbo LQ1 failure.. almost "always" piston or bearing (rod or crank). Most all, if not all, 60* V6's came with forged rods thereby "usually" forcing pistons and bearings to throw in the towel first given an overpressure situation.
just my initial thoughts...
*Edited for clarity
[This message has been edited by msweldon (edited 02-07-2015).]
true but he also said that the engine could have already been hydrolocked before purchase. However, the stock rod bolts should always be replaced with an ARP or equivalent for ANY turbo lq1 build as his second failure shows. Matt Hawkins ran and is still running 400hp for years, and several hot rod power tours, on an lq1 crate with only the pistons and rod bolts replaced. He did shred a timing chain however. Regardless, I would venture that anything with 400hp and greater with stock 60* rods / pistons / crank, needs to be carefully and judiciously tuned as the weak points will surface quickly at these power levels.
I got into the more fine points of the teardown, I've concluded that I bent 2 rods. How bent?
Cylinder 1's piston was being lightly hit by the cranks counterweight because the rod was short. This is what was making all the racket.
Cylinder 2's piston was a bit crooked in the bore, so the piston and bore had a fair amount of scuffing. The bores have some scratching, which will likely persuade me to use my old block, as its bores are still in excellent shape. I need to get a bore gage and inspect the two blocks and pistons further and make that call.
Inspecting the heads I found no evidence of any issues. The sparkplugs look perfect, carbon deposits were very consistent across the heads and pistons.
One somewhat alarming thing I found, was that it appears as though the PCV system was allowing quite a lot of oil into the intake manifold. The runners were wet with oil, and quite a bit was pooled in the bottom of the intake manifold. There was not a drop of oil in my intercooler, so I know the turbo and the oil separation system worked perfectly. But the PCV line was clearly passing oil.
I also had a chance to drop the forged crank, the Eagle rods, and the new pistons in to check clearances once again. The good news is everything fits and spins perfectly. I was expecting to have some problems with block clearance. The 3500's and 3900's have a clearancing for the big end of the rods right by the oil pan. But minimum clearances seem to be right at around 1/8". I don't know about how it'll effect the windage tray yet, but that's nothing a couple of washers couldn't fix if need be.
I was interested in seeing what happened inside the motor. I highly doubt the rods were bent because of ring butting as I have done that before in a Turbo TPI 305. The ring butt sign will register as a groove in the side of the cylinder bore the length of the stroke at the ring gap location.
The pop or backfire you heard was probably the result of misfire at the upper extremes of the boost level where the ignition system is taxed. I've had the problem for quite a while because it keeps cropping up in different areas as a result of a weak/bad coil, bad plug wire, too wide a plug gap for the boost level with high compression and too much water in the water/meth injection mix. Spark knock severe enough to bend a stock rod will almost certainly chip a stock piston, or break the ring land (done that before to). It looks like the rods bent because they couldn't handle it and that's likely why everything else looks good.
I'm not sure what your new connecting rod length is but if it's still 5.7" and you did the rotating assembly clearance check before the 7x ring was installed, recheck it looking at the clearance between pistons #3 and 4 on the 7x ring side of the bottom pin area of the piston. Although my problem was the result of increased stroke you'll want to make sure clearance is adequate for changes associated with high rpm. If you have 6" rods it will be fine.
I checked and see that you are using 5.7" rods so definitely check the 7x ring clearance relative to the piston as it extends outward further than the crank weights.
I also saw your remark about lowering compression to run 20 psi. With great intercooling and premium fuel it shouldn't be necessary for the 3.4 DOHC as I've hit 20 psi a number of times at 11:1 compression although I have water/meth injection. I doubt 10:1 would pose a problem for you at that level of boost.
[This message has been edited by Joseph Upson (edited 02-12-2015).]
I did a light glaze busting on cylinder #2, It showed me that the cylinder scuffing from the crooked piston would require an overbore. It also had some moderate bore scratches mostly near the top. One is particularly bad. The block is fine, but is not serviceable at 92mm 3.622" anymore.
So, I pulled my old '94 block off the floor and prepped it for service. It's bores are perfect, even after a glaze busting. Had to clean the block up quite a bit, it had some sediment in the water jackets. I also bottom tapped the headbolt holes so my studs would fit.
I did my fit check with the 7x ring in place. It was roughly 1/4" from the bottom of pistons 3 and 4. The pistons are actually shorter than the stockers by quite a bit. So it's all good there!
I also am back at it machining the connecting rods small end down to the width of the big end. It's actually the toughest process I've had to do on the rods. I'm half way done with them now. Very time consuming and tedious, but very much worth it.
can you measure the OD on the new reluctor and compare it to the stock 3.4 wheel for me?
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
The new ring is a 0.411" radius increase over the 5.750" diameter
Narrowing the small end of the rod on the mill
Cylinder #2 bore scuffing and bad scratch after glaze busting
Same bore, different view
94 piston, Custom forged piston, 96-97 piston You can see the difference in the height on the 96-97. They are MUCH taller
So once I finish the rod narrowing, will start the weight matching, then I'll have to have the crank balanced. Then I can file my rings, and start assembling the short block.
[This message has been edited by Fierobsessed (edited 02-15-2015).]
Got my crank back from the machine shop, all balanced and ready to roll!
Block ready to receive
Dropped the crank in
Plastigage, then assembly lube... and then the first piston went in. And that's when all hell broke loose. This was the piston at top dead center. And that, is well below the deck. My heart began to sink. Something Is seriously wrong.
So, I measured the stroke of the crank, and found that it was only 2.990"
Someone screwed up big time. I was sent the wrong crank. It was advertised as being from a "2006 Impala 3.9" and it certainly wasn't.
That means I'm out about $500 due to the purchase of the crank + the balancing all gone to waste
I contacted the seller to see if the will out of good grace fix their mistake. However, I've had the crank since October, they can totally say go to hell. I'm definitely out the money for balancing though. And that sucks.
I was really looking forward to putting this bulletproof short block together this weekend, but it looks like Its going to be a few weeks at least.
Sorry to hear that, that really sucks, just bad luck.
I just had my DDs engine get ruined (wrx cam seized for no reason at 2500rpms and blew the timing gears and belt to hell and trashed all the valves and pistons) and had to waste like 400 bucks on a massive tow, and triple A covered 100 miles of the tow.
Wasting money feels awful
I am really looking forwards to when this does end up going back together though, it is inspiring how clean your engine and turbo setup is.
I did contact them, it was purchased too long ago to return. So I proposed an exchange where I pay shipping both ways. They're mulling it over, but It looks like they will likely go for it. I was able to prove that they were still mis advertising 3.5L cranks as 3.9L cranks. Hopefully I'll have this issue resolved shortly.
They did good by me. So now I have the correct stroke, forged 3900 crank. I'll clean it up, change reluctor wheel out for the 7X, then send it off to be balanced.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
First order of business, I changed out the reluctor for the 7X. That was a piece of cake now that I have some experience doing that already.
The second step was to throw the crank into the block and load a rod/piston assembly in, moving it bore to bore to clearance check everything. Funny thing about that, was when I had the 2.991" stroke crank, clearances were excellent, which at the time was a surprise to me. And yet, somehow I didn't pick up on the fact that the reason it cleared everything so well was because it was missing 0.32" of stroke! Now that I have the right crank, checking clearances was a more serious matter.
Turns out, that there were two clearance issues with the block: The rod bolt was solidly hitting the inside of the block near the oil pan rail.
The other clearance issue was the big end of the rod just grazing the bottom of the bore. Its hard to describe, but you can see where I marked the interferences.
So I took the block outside and used a grinder bit in a dremel to clearance the required spots. I washed the block down thoroughly, dried it off and re-oiled the bores.
Once that was done, I reinstalled the crank, and moved the piston/rod assembly through each bore to recheck my clearances. I used a piece of emery cloth about .030" thick as a feeler for the tight spots. Everything now checks out good.
Monday, I'm going to drop the crank off for the balance job, and hopefully soon I can start assembling the bottom end again.
Originally posted by Fierobsessed: I did contact them, it was purchased too long ago to return. So I proposed an exchange where I pay shipping both ways. They're mulling it over, but It looks like they will likely go for it. I was able to prove that they were still mis advertising 3.5L cranks as 3.9L cranks. Hopefully I'll have this issue resolved shortly.
It's the 3500 non VVT and 3900 cranks that are the same, glad you got it worked out, I totally missed that the 3.4 DOHC block is not relieved to clear the connecting rod bolts in the same manner that the other 60 degree blocks are.
It's the same stroke as stock, so the only difference is the rod journal diameter. I don't see why contemporary 60 degree V6 blocks would have reliefs, but obviously the modern ones should.
It's the 3500 non VVT and 3900 cranks that are the same, glad you got it worked out, I totally missed that the 3.4 DOHC block is not relieved to clear the connecting rod bolts in the same manner that the other 60 degree blocks are.
Even then, they are mostly the same. different reluctors, different forging. But, they are interchangeable otherwise. I learned that the cranks with the big "5" cast into them are 3500 VVT cranks, and the ones with the big "8" cast into them are 3900's.
The fun bits are underway in my garage, the assembly of the engine has been coming along a little bit now. It seems I have minimal time to actually work on it.
I'm doing some cleaning, not so much work with paint as the paint was still pretty fresh. I just want to slap it all together and get back to driving it already before the oppressive heat comes. Perhaps I'm a little impatient.
Some bottom end assembly. If this doesn't make you happy, then you don't deserve to call yourself a car person.
Figured there wasn't any harm in checking out the oil pump, and maybe think a little about bumping up the pressure. This oil pump is massive. It is the largest oil pump of this type that I have ever seen. It's gears are so big, that it easily doubles the volume of a Chevy SBC high volume aftermarket pump. That's how crazy big it is.
Bumping the pressure up a little isn't much of a task. I removed the cover and pushed the little pin out. I then shoved a 1/4" split washer in and put the pin back in place. The spring was only compressed about 1/4" from resting, but now its more like 5/16" so its a slight bit of an improvement
With the oil pump settled I bolted the mains and the windage tray back down with the studs.
I did have to grind a little bit of material off the oil pump to help it clear the studs nut
Once all that was done, and everything was in order, I put the timing cover assembly on the engine, and installed the oil pan. I flipped the engine back upright. I always do this with the 3.4 DOHC's. I put a second O-ring on the oil pump drive assembly. I used a 30mm X 35mm X 2.5mm O-ring I got at the local hardware store. The O-ring that is on the assembly normally is highly unreliable. The factory one that was on this engine had a couple months of use and was so hard it broke of in pieces. The second O-ring seals into a groove that is already present in the block and prevents any possible leakage. This is one of this engines biggest natural flaws. That and intake gaskets, but I'll get to that in a minute here.
Cleaned the head surfaces and installed the studs and gaskets. The money shot!
Ok so, about intake gaskets... We have a serious issue here that I am trying to solve in a reasonable manner. What I have learned about the 3.4 DOHC over the years is that two things cause the intake gaskets to fail, and both for the same reason. That reason is oil. These gaskets swell when large amounts of oil pool on the sealing surfaces, and frequently this leads to them extruding out of place and letting air in.
I say there are two causes for oil to pool on these gaskets. One is valve cover or cam carrier gasket leaks that drip straight down onto the gasket, and it pools there. That's easy to see and solve. So I'm not worried about that.
The other source is what I've confirmed to be the PCV system. My air intake is absolutely dry of any oil up to the throttle blade. and yet oil is pooling inside the intake and getting into the engine, and potentially damaging the gaskets. When I took the motor apart, I noticed that there was oil all over the PCV valve and the tubes that link it to the intake and its ventilation source, which is the nipple on the valley cover/Oil distribution manifold. Somehow, oil is able to make in into this vent nipple.
I'd strongly prefer to keep the PCV system intact, as this car is emissions legal still somehow.
So I'm looking for ideas on what to do to keep oil from coming out the nipple on the manifold/cover The valley cover
I opened one of them up to study the baffle system that is supposed to prevent oil ingestion This left me wondering if the intermediate shaft (the dummy cam) is throwing oil into the inlet or something. I don't know. I'm kind at a loss for ideas here.
Otherwise, the assembly is going quite well. I can't wait to get the thing all back together.
If the oil pump had a paper gasket between the halves, that is most likely a shim. Might want to spin the pump to check if the gears spin freely and not bind up on the outer housing. I found that out the hard way when I was building my 3.4, had to face the gears on a lathe.
Have you considered using a vacuum pump and catch can? I would at least use a catch can with the PCV system since it wasn't originally designed to be used with boost.
I have them, considered using them too. But I found that there is no nice way to integrate them, and they would hardly be worth the effort.
First, the rear main is the same for both styles. So there was no advantage there. Only the two center ones will fit with the sheet metal pan, negating the possibility of using the front main. So, I'd have had to have the block align bored for those two mains.
I considered possibly using the cast aluminum pan with the front three cross bolted mains, but then the exhaust and front mount wouldn't fit. On top of the fact that the pan doesn't bolt up anyway, not even close. Sorta ruled it out for me. Not saying I couldn't, but that it wouldn't be worth all the effort, especially when the windage tray is so thick and strong, pretty much provides the same function as the cross bolted mains. The one thing I did consider though, is that the metal that those mains were made of appeared much better than the cast caps that the 3.4 DOHC has.
There is definitely a possibility of improving the mains, but I only took the option to install the studs. Even then, they are still torqued to 70lb-ft, as not to warp the caps out of round.
I figured you had thought it through, and honestly didn't realize the pans weren't swappable, I guess there had to be a few more things on the TDC that didn't transfer right over
Well keep up the good work your fab work and packaging is top notch
Speaking of thinking of things through, I started doing the timing belt and assembly, when I ran into a snag, literally.
I had sealed up the bottom end last week and bolted the heads, cam carriers and timing housing assembly. I put 5 quarts of oil in, and used a power drill to turn the intermediate shaft to prime the oil pump. All this was going well.
But today, I when I was turning the motor as part of doing timing, something was causing the crank to have hard spots in its rotation. A snag of some sort. This put me in a fowl state.
So, reluctantly, I destroyed the oil pan gasket when removing the oil pan. The cause was apparent immediately.
Well, didn't think of everything did I now? Hah. Well, at least the gasket was destroyed before I even removed the pan. It seems as though the pan gasket hangs inside the rail about 1/8". It needs to be nearly flush where the rods swing close. So I have to go get another gasket and modify it a little.
By the way, I find this is my preferred method of assembly. Keep your torque specs close, and your torque wrench closer.
I usually don't find myself getting back into the bottom end this late in the assembly, but it happened. Twice actually. I had to pull the pan right after I put it on the first time when I found that my spacer washers for the studs were too wide, and did not allow the oil pump drive shaft to slip into the oil pump. A little grinding on those washers fixed that issue.
As the engine is coming together. (slowly, as I have like no time at all anymore these days) I think its time I take care of a problem I was having with the clutch. I had an issue where the clutch would not disengage when the engine was at high RPM. I've heard of it referred to as High RPM Clutch Lockout. I had this problem even before I turbocharged the engine, and switched to the 6 speed.
My theory is that the pressure plate needs more then just the 3 straps holding it against the diaphragm. So... I'm improvising a bit.
I added some springs to help hold the plate stable.
hopefully, this little mod will fix that issue.
I should be good for slipping the engine onto the cradle next.
What rpm are you shifting at? Reason I ask is I had a FWD clutch from clutchnet on my blazer, shifted at 7k a few times and never had an issue with clutch lockout.
Somewhere in the 5500-6500 range. I don't think its a clutchnet disk issue though. I've had this problem with every Sachs pressure plate I've had. I'm hoping the extra tension against the diaphragm will help at high rpm. I recall even having this problem when I had just a PR 3.4 in the car, and again when I changed to the first iteration of the 3.4 DOHC. They've all had the same model pressure plate.
The mod I did to increase clamping force and help pedal feel also had a small decreasing effect on the tension too. I'm just putting some non scientific faith in these springs, hoping they'll help a bunch.
It would seem like an easy answer to go that route. But I've already purchased two uprated pressure plates to build this car. The first one from clutchnet was so bad, I couldn't justify even attempting to install it for the reason that it likely would have not worked at all, It had uneven fingers.
The second purchase was one from Spec. This one was perfectly well built, and easily could have handled my application, horsepower wise. However, it required a super thick clutch disc, which I don't have. So, it would have likely failed very quickly.
Finally, after studying what Spec did to up the torque capacity, I decided to modify a stock plate to be able to handle the torque by moving the fulcrum inward like the Spec plate, but not as far so that I could fit my custom clutchnet "F40" disk.
Power handling was great with this combo, clutch feel was okay, but trending towards boarderline for a daily. But I've always had trouble getting the clutch to stay disengaged during a High RPM shift. It wouldn't even allow the shifter to come out of gear. I'm not really worried about the springs flinging out, the springs will be operating at nearly fully compressed, and they will only have just the last bit of the spring exposed. Perhaps, I could have layered up some more straps if I had them. But that would mean I need yet another donor pressure plate.
I just sent the clutch pressure plate and the flywheel out for balancing. I figured since I've got the crank balanced, it would make good sense to balance the flywheel. especially since I did so much machining to it previously.
When the flywheel gets back, I can load the engine back onto the cradle and get the package all dressed back up for installation.
If you want to try the springs, maybe you can add pins that anchor to the flywheel and protrude through the rivets on the PP to keep the spring from walking out?
Or add weights to the fingers like a centerforce PP?
I shift my LS4/F40 at 7K quite often without issue, but my clutch/pressure plate setup is completely different (10" ford setup). The only shifting issue I ever had was aggressive 3rd gear up-shifts where the getrag select cable (used as a shift cable) was buckling as it reached maximum extension. Reworking the bracket to use the thicker and longer extending Isuzu Shift cable fixed that issue.
If you are going to go the spring route, they really should be positively anchored at both ends (recessed hole on the flywheel & spot weld a centering dimple on the head of the rivet). As they flex/vibrate and experience rotational forces, the springs will likely walk out from the current mounting hole. Once you lose one, the other two will likely cause an imbalance issue, and the loose spring will likely get hung up on something within the bellhousing and cause further damage.
