I know I can't re-use the old cyl head bolts, so I need to order a set of cyl head bolts, specifically for my 3.4 swap into my Fiero. I'd prefer to just order a set of new factory 2.8 cyl head bolts... is that OK? Or should I be ordering them for a 93-95 Camaro / Firebird (from which this motor came)?
Second question... when ordering a head gasket set... do I order a head gasket for a 3.4 Camaro / Firebird, or a 2.8 Pontiac Fiero (or is there even a difference)? I'll be using heads that came from a 2.8 Fiero onto my 3.4 engine.
I know I can't re-use the old cyl head bolts, so I need to order a set of cyl head bolts, specifically for my 3.4 swap into my Fiero. I'd prefer to just order a set of new factory 2.8 cyl head bolts... is that OK? Or should I be ordering them for a 93-95 Camaro / Firebird (from which this motor came)?
Second question... when ordering a head gasket set... do I order a head gasket for a 3.4 Camaro / Firebird, or a 2.8 Pontiac Fiero (or is there even a difference)? I'll be using heads that came from a 2.8 Fiero onto my 3.4 engine.
Thank you!
I don't know, I've read places that the original head bolts are reusable and not torque to yield, but replacements are, the factory service manual doesn't say to replace them, it does say to clean them, so that might indicate they are "reusable". I'm getting new fel pro bolts for mine, but it is interesting. I wonder if the torquing instructions are different for the TTY bolts vs the factory originals.
Another thing I found while looking in the manual for this is the valve lash adjustment, I don't know if my tired brain is reading this wrong, but it appears that you tighten just until you can't turn the pushrod, then tighten it another 1.5 turns
Anyhow for replacement bolts/head gaskets, look on Rock auto, compare part numbers, if they are both the same, then get whichever you want, although the head gaskets might be sized differently, as the cyl bore is 3mm larger, don't know if that would make a difference or not (also assuming the heads are the same, even if the cyl bore is not?)
Hmm, I'm just reading threads that warn against doing 1.5 additional turns, saying perhaps the manual intended to say one 0.5 additional turn, instead of 1.5 turns, now I'm confused haha.
Another thing I found while looking in the manual for this is the valve lash adjustment, I don't know if my tired brain is reading this wrong, but it appears that you tighten just until you can't turn the pushrod, then tighten it another 1.5 turns.
Lucky for you, I researched this quite extensively several years ago.
I wanted to take this opportunity to discuss the methodology of adjusting valve lash. The last time I adjusted valve lash was back in 1977 after I swapped a lumpy camshaft with solid lifters into my big-block 396ci Chevy.
This is the first time I've ever adjusted the valve lash on a 2.8 engine. I've read all the numerous posts about which rockers to adjust when, and "spinning" the push rods while tightening the rocker nuts until the push rods start to bind. Then there's the debate about how many turns of the nut after finding zero lash. I gotta be honest... I didn't feel a lot of those posted methods were very convincing. Here's how I did it....
First, for each cylinder I determined when it was at TDC of the compression stroke. This was done by rotating the crank using a wrench on the front pulley (with the spark plugs out it's easy) and seeing when the exhaust valve is closing and the intake valve is opening. That's TDC, but on the exhaust stroke. Turn the crank 360° (watch the timing marks go by... stop on the third one), and this is TDC on the compression stroke.
With the rocker nut loose, grab the rocker at the valve end tip and lift it. You'll notice the play. You don't even have to see it, you can feel it. Slowly start to turn the socket wrench on the rocker nut and you can feel the play becoming less and less. And now I've got something critical to add...
Do not get fooled by a lack of play due to your socket wrench putting pressure on the rocker ball.
Lucky for me, I noticed this very quickly, but I can certainly see how an inexperienced mechanic could get completely fooled by this! It is very important that the socket wrench is taken right off the rocker nut when lifting the end of the rocker to check for play. (A deep socket rests on the rocker ball, and the wall of the socket can also push against the inside of the rocker, both of which can prevent the rocker from easily moving.) Otherwise it's way too easy to come to the conclusion that you've reached zero lash when in reality you could still be way off. Using this method I was able to determine zero lash to perfection.
And now the lifter pre-load. I gave each rocker nut exactly 1 1/2 turns after finding zero lash. I suspect why some people suggest less pre-load is because the "spinning" push rod method to find zero lash is so imprecise that many people would probably have already gone beyond zero lash. Therefore, adding another 1 1/2 turns would be exceeding the recommended lifter pre-load for this application (if the rocker nut was tightened too much while setting zero lash).
Before I removed the original rockers, I checked to see what the pre-load was. It was all over the place, but it seemed like 1/2 turn past zero lash was the usual. That's not enough.
Originally posted by 1985 Fiero GT: I don't know, I've read places that the original head bolts are reusable and not torque to yield, but replacements are, the factory service manual doesn't say to replace them, it does say to clean them, so that might indicate they are "reusable". I'm getting new fel pro bolts for mine, but it is interesting. I wonder if the torquing instructions are different for the TTY bolts vs the factory originals.
Anyhow for replacement bolts/head gaskets, look on Rock auto, compare part numbers, if they are both the same, then get whichever you want, although the head gaskets might be sized differently, as the cyl bore is 3mm larger, don't know if that would make a difference or not (also assuming the heads are the same, even if the cyl bore is not?
Yeah, I honestly wasn't sure... they show two different part numbers for a variety of different bolt sets... mostly because the 3.4 Camaro / Firebird has a unique / weird bolt that I don't see in the Fiero bolt sets. The only thing I did see though, was a bolt set from FelPro (likely the one you're getting) which seemed to have the same part number between the two of them. It also came with a ground stud for the outside of the cyl head that you can use to connect your battery terminal onto (like on the Iron Dukes).
The last time I tried to do a cyl head bolt on a V6/60 was ~1998, and I ripped the threads out. I'm convinced my torque wrench was garbage and simply didn't work. Or I didn't understand the difference between Newton Meters and Foot-Pounds. Either way, I bought a whole new set of torque wrenches.
This is for my 3.4 though, and it's a reman... so I don't really know what bolts it has on it. It's best to just change them out.
For head gaskets, I just ordered a set for the 3.4 due to the obvious bore size difference. I ended up going with Mahle since they had Graphite gaskets. I wanted the Victor Reinz, but they were out. FelPro is still great... but most of their stuff is made in China now, and honestly... unless it's old stock from the 90s or early 2000s... I really don't like to use FelPro anymore. I ended up buying the last two Mahle head gaskets they (Rock Auto) had.
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Originally posted by 1985 Fiero GT: Another thing I found while looking in the manual for this is the valve lash adjustment, I don't know if my tired brain is reading this wrong, but it appears that you tighten just until you can't turn the pushrod, then tighten it another 1.5 turns
Hah... yes, it was like 15 years ago since I last did this... so definitely don't take anything I say as gospel until I've gone and done this again. I get to do all this stuff over again. But I was just a kid 1,200 miles away from my parents, wrenching in a parking lot on the weekends when the rental office was closed (so they wouldn't see).
Yeah, the fel pro bolt set has all the bolts and one stud, my Fiero used the stud as well (off hand I forget what for, and I just did this on Monday) I seem to recall it not being a "necessary" thing, something I could leave off or fasten somewhere else, and the Fiero store set, doesn't have the stud pictured, but I'll probably use the stud anyhow.
Hey, the fact you remember all you do is pretty good, considering I can't remember what that stud is for, and I disassembled that on Monday haha.
Yeah, the fel pro bolt set has all the bolts and one stud, my Fiero used the stud as well (off hand I forget what for, and I just did this on Monday) I seem to recall it not being a "necessary" thing, something I could leave off or fasten somewhere else, and the Fiero store set, doesn't have the stud pictured, but I'll probably use the stud anyhow.
Hey, the fact you remember all you do is pretty good, considering I can't remember what that stud is for, and I disassembled that on Monday haha.
Well, just going off this rebuild I'm doing with my daughter on the Iron Duke, it seems like the head-bolt with the studs are used as grounding points. Which makes total sense of course, you're literally tying directly into the block itself. You'll notice that those bolts all seem to have a "Teflon" tape on them. I don't think it actually is Teflon, and I'm wondering if maybe it's some kind of dry-dialectic wrap. Both the bolts for my daughter's Iron Duke (which had studs on them) had that... and neither one of them went into a water port. So, who knows...
Originally posted by 82-T/A [At Work]: Well, just going off this rebuild I'm doing with my daughter on the Iron Duke, it seems like the head-bolt with the studs are used as grounding points. Which makes total sense of course, you're literally tying directly into the block itself. You'll notice that those bolts all seem to have a "Teflon" tape on them. I don't think it actually is Teflon, and I'm wondering if maybe it's some kind of dry-dialectic wrap. Both the bolts for my daughter's Iron Duke (which had studs on them) had that... and neither one of them went into a water port. So, who knows...
It's not the ground, that is above one of the exhaust ports, I'm pretty sure it is to hold the bracket that holds the hard fuel lines,
It's not the ground, that is above one of the exhaust ports, I'm pretty sure it is to hold the bracket that holds the hard fuel lines,
on some 2.8s it's both actually. these get super weird and weirdly enough some 3.4s and 2.8l use the same headbolts despite having different head thicknesses and my 84 iron duke and my v6 actually directly use the same headbolts..which is the exception not the norm for Fieros
on some 2.8s it's both actually. these get super weird and weirdly enough some 3.4s and 2.8l use the same headbolts despite having different head thicknesses and my 84 iron duke and my v6 actually directly use the same headbolts..which is the exception not the norm for Fieros
I'm 99% sure that the 3.4l and the 2.8 use exactly the same heads, at least the pushrod 3.4l that 82-T/A is installing with ported 2.8l heads, and sending me the regular 3.4l heads to install on my 2.8l. definitely the dual twin cam 3.4 had different heads, maybe that's what you are talking about.
The 3.4L/2.8L head bolts are exactly the same and they are not reusable. If the instruction says to torque them in stages of specific lbs/ft values and then add specific degrees then is a torque to yield bolt and they can't be re used.
The 3.4L/2.8L head bolts are exactly the same and they are not reusable. If the instruction says to torque them in stages of specific lbs/ft values and then add specific degrees then is a torque to yield bolt and they can't be re used.
The factory service manual, talking about the factory installed bolts, only mentions one torque spec, and says to clean and reinstall the old ones, indicating that they are reusable. I think replacement bolts are TTY but I'm not sure about that.
on some 2.8s it's both actually. these get super weird and weirdly enough some 3.4s and 2.8l use the same headbolts despite having different head thicknesses and my 84 iron duke and my v6 actually directly use the same headbolts..which is the exception not the norm for Fieros
If the part number is exactly the same on the Fiero 2.8 and the Camaro/Firebird 3.4 heads, why would head thickness be different?
I don't know if the Iron Duke bolts were TTY, but we torqued them in three increments... 35-65-90 (or whatever the final torque specification was).
I've watched enough shows to know that even though a bolt may say "torque to this spec," it can be better to torque it down in proper sequence in three stages. Since the bolts do stretch somewhat, it'll ensure the final torque is more accurate when everything settles.
I don't know anything about an "extra turn" though... that makes me worried, and makes me wonder if that's why (back in the day), I ripped the threads out of my V6/60 engine block when I was re-installing the cyl head. I had to remove it because my exhaust manifold cracked, and the exhaust stud broke off on it.
The factory service manual, talking about the factory installed bolts, only mentions one torque spec, and says to clean and reinstall the old ones, indicating that they are reusable. I think replacement bolts are TTY but I'm not sure about that.
What do you mean? Of course it is vintage, it was made specifically by gm for the Fiero, which is itself vintage. The only thing relevant in that thread is that the replacement bolts were very slightly smaller then the original Pontiac bolts, which led to the new ones stripping out, just one more reason to reuse old bolts in this case, especially since gm says to. When I put my heads on, I will carefully compare the new felpro bolts and the old gm ones, if the fel pro bolts are any thinner, I will certainly clean and reuse the gm ones, as that is what gm says to do, and I don't want to risk stripping out my block like the OP in that thread did because the replacement bolts were to thin. I will use sealant and will torque to 66 lb. Ft. as found in the factory service manual.
[This message has been edited by 1985 Fiero GT (edited 05-27-2024).]
What do you mean? Of course it is vintage, it was made specifically by gm for the Fiero, which is itself vintage. The only thing relevant in that thread is that the replacement bolts were very slightly smaller then the original Pontiac bolts, which led to the new ones stripping out, just one more reason to reuse old bolts in this case, especially since gm says to. When I put my heads on, I will carefully compare the new felpro bolts and the old gm ones, if the fel pro bolts are any thinner, I will certainly clean and reuse the gm ones, as that is what gm says to do, and I don't want to risk stripping out my block like the OP in that thread did because the replacement bolts were to thin. I will use sealant and will torque to 66 lb. Ft. as found in the factory service manual.
Of course you'll have to use sealant on a 2.8 because the bolt threads are exposed to the coolant! That doesn't happen on the 3.4L or any other 60 degree V6!
[This message has been edited by La fiera (edited 05-30-2024).]
Il be straight forward , yes the head bolts are reusable Just inspect them If they are super rusted from sitting in the coolant passages then yes I would run a different set , they are the same for all that have iron heads so yes 3.1 and 3.4 are same head bolt
Valve lash 3/4 turn after zero has been the go to Even had delta cams confirm 3/4
Valve lash 3/4 turn after zero has been the go to Even had delta cams confirm 3/4
I don't have that problem, I use solid flat tappets. When I used to use hydraulics I used 1/8 turn. Reason being in case the lifters do pump up there were less chances for the valves held open to kiss the pistons. The other problem with hydraulics is that as the oil gets hot it gets thinner and also gets aerated. That means more air bubbles that can collapse making the cam loose duration and lift immensely.
1985 Fiero GT is correct about that. But it is confusing for everyone because the 88 fiero GM service manual states 66 ft./lbs for the torque on the head bolts. The issue is the Haynes Manual says 65 to 90 ft./lbs.
It would of been beneficial for them to explain further in detail to torque a 1st pass at 65ft./lbs and the 90ft./lbs on the 2nd pass. This is the issue, no detail or info. So we are guessing / assuming this is the correct procedure. But, it is interesting that the 88 fiero GM service manual only specs it at 66 ft.lbs.
Who is correct?
You certainly don't want to blow a head gasket for a mistake, or strip a bolt in the 2.8L block because of confusion. Big variation in torque.
It's not the first time GM has made mistakes in a shop manual.
About the rocker adjustment. There is confusion also, but remember...this is on stock parts. The other issue that was mentioned in the past was aftermarket rocker studs with a different thread pitch. Resulting in un-acurate turns on the valve lash. But I can't compare the stock to aftermarket rocker studs, as I only seen stock studs.
Finally, the use of the original head bolts is ok, but my opinion is if your putting lots of money into your 2.8 or 3.4 rebuild, you think cheaping out on 40$ for bolts will make a difference? No... You have new bolts, and peace of mind. They are non TTY bolts, and are reusable. TTY bolts are indicated when you torque the bolts to an added degree value. Your actually "stretching" the threads to the tightening specs. That why it's a on time use.
You can do what you want, but in the end your the boss of your rebuild. I just don't like taking chances when you can do the job right the first time.
I have also heard and people that did a 2.8, that 3/4 turn after the zero lash on the push-rod is the best adjustment.
Originally posted by fierogt28: TTY bolts are indicated when you torque the bolts to an added degree value. Your actually "stretching" the threads to the tightening specs.
The only way to sensibly torque a bolt to (or beyond) its yield point is using a torque+angle procedure.
However, a torque+angle tightening procedure can also be used to stretch a bolt while remaining in the elastic (i.e. reusable) domain.
I never understood why someone spends money and time getting their engine rebuild and cheap out on the lesser things like head bolts. Thinking that by re using the head bolts and saving $30 will not bite them back with quadruple force once one of those overworked/overstretched gives in. Then more time and money has to be spent and to top it off they would want to re use the already torqued head gasket! That's where the "shade tree mechanic" fraise came to be I guess! Good luck!
I never understood why someone spends money and time getting their engine rebuild and cheap out on the lesser things like head bolts. Thinking that by re using the head bolts and saving $30 will not bite them back with quadruple force once one of those overworked/overstretched gives in. Then more time and money has to be spent and to top it off they would want to re use the already torqued head gasket! That's where the "shade tree mechanic" fraise came to be I guess! Good luck!
I personally would also buy new bolts and head gaskets, and indeed I have, the only reason I'm hesitant in using the new bolts is that there are several stories of the threads being stripped, and the topic mentioned earlier by you gives a reason for that, the new replacement bolts were a smaller diameter than the originals, meaning the threads weren't making full contact, and stripped out the block. I have threaded in a new felpro bolt by hand, and a cleaned original bolt and the felpro is loose to the point of wiggling even when fully threaded in, whereas the original can be easily threaded by hand (no stretching of the threads) but does not wiggle. If you end up buying new bolts and they work, that's good, but I for one will reuse the old for peace of mind, as that seems to be a legitimate problem with our engines, replacement bolts (at least the one I got, and the ones in that topic: https://www.fiero.nl/forum/Forum2/HTML/143273.html ) are not what they are supposed to be.
Some people can’t and won’t understand the concept of 30$ won’t “break the bank”.
I guess some do.
It’s like rebuilding the complete engine, and using a worn out oil pump.
Come on man... 1985 Fiero GT is literally like 18 years old. Were you this mature then? I was knocking over Port-O-Potties, streaking through Waffle Houses, and tricking my drunk friends into lap dances with morbidly obese girls when I was his age. Give the kid a break, he's just asking questions. Besides, he's literally from your hometown... where is your New Brunswick pride?
