v80z Posted December 4, 2006 Share Posted December 4, 2006 I did not retorque the heads after 1 hour of running. In fact I have about 5 hours run time on the motor since replacing the heads. I was chasing what I thought was a header leak but found a compression leak on #1 cylinder out of the front between the head and the block. Is the gasket blown? Do you think retorquing is worth a try? Flame ON !!! I deserve it . Quote Link to comment Share on other sites More sharing options...
80LS1T Posted December 4, 2006 Share Posted December 4, 2006 I have never retorqued a head afer running and engine and I've never hand an issue... Im not saying its a bad idea but I don't think its manditory. Chances are the gasket is blown if you can can hear it leaking. But its probably worth a try to retorque them. Guy Quote Link to comment Share on other sites More sharing options...
dustin280zx Posted December 4, 2006 Share Posted December 4, 2006 you should always retorque engine parts after it is warm (like 5 minutes of runnign the engine) just to be safe and make sure everything is sealed. i usually get 1/2 turn to 1/4 turn on head bolts. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 4, 2006 Share Posted December 4, 2006 you should always retorque engine parts after it is warm (like 5 minutes of runnign the engine) just to be safe and make sure everything is sealed. i usually get 1/2 turn to 1/4 turn on head bolts. That is really unusual, sounds like you have other problems!! Mainly because that's not how it's supposed to be done. Re-torqueing is supposed to back the bolt or nut off, then re-torque. If you getting that much additional turn on a bolt or nut then somethings wrong IMO. Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted December 4, 2006 Share Posted December 4, 2006 Did you chase the head bolt threads prior to reassembly? If you are using a good set of head gaskets you should not have to retorque them. But you always chase the head bolt threads. This cleans them up, and if you did not maybe the head bolt thread had some corrosion and effected the torque specs. It probably has blown the head gasket, so retorquing will not help. Reccomend the nitro seal head gaskets made by victor reinz, they have not failed me in nomal engines. Presently I have to use copper head gaskets. Might consider using head studs in place of bolts. Hope this helps. John Quote Link to comment Share on other sites More sharing options...
dustin280zx Posted December 4, 2006 Share Posted December 4, 2006 dr. hunt, it may not be 1/2 a turn or so, but its alittle bit. also this was on a pulling tractor that had the original head studs and was over 50 years old. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 4, 2006 Share Posted December 4, 2006 As long as the experts are here, is this even possible on an LS series motor? They have the use once head bolts that need an angle gauge instead of a torque wrench. Quote Link to comment Share on other sites More sharing options...
pparaska Posted December 4, 2006 Share Posted December 4, 2006 Be careful with head studs is the first caution for you. Since you have two sets of threads per fastener to settle, one in the block, one at the stud/nut, you should be aware that some settling may occur, and retorqing is advised, from what I've read and experienced. I know, it's a pain, as you have to pull the headers off the engine to do a retorque. Also, I found the combination of MLS type gaskets and head studs may even increase the need to retorque. You have more internal gasket interfaces with the MLS gasket, and this can mean that you need to retorque because of this alone. Check out this thread: http://forums.hybridz.org/showthread.php?p=340135 Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 4, 2006 Share Posted December 4, 2006 dr. hunt, it may not be 1/2 a turn or so, but its alittle bit. also this was on a pulling tractor that had the original head studs and was over 50 years old. Well, I still don't see it, I've done diesels, tractors, Continental industrial gas motors, 6 bangers, 4 bangers, etc. Probably what JNJ says. Anyway, the proper scenario is to back the bolt or stud off and re-torque it, not just re-torque it. Torque wrenches don't work very well unless it's a seamless movement that results in the torque click that you hear. If you start at 63 lb and going to 65lb, it'll just click and not move the bolt even though it needs to move the bolt, but that's my experience and my opinion. Quote Link to comment Share on other sites More sharing options...
pparaska Posted December 4, 2006 Share Posted December 4, 2006 Dr_hunt - you're talking about the difference between static and dynamic friction. If the bolt is tight enough that you can't break the static friction of the threads/bolthead/head interfaces, then you'd never know that the torque while turning the fastener is actually lower then where you are statically. A bolt that isn't turning and has 65 ftlbs of torque on it's head will probably be less stretched (and impart less clamping force, what we should care about) than a bolt that is brought to 65 ftlbs of torque while it's turning. To let it turn while you tighten it, you need to loosen it a bit. I wouldn't loosen it much though! Just enough to let the bolt turn to get the torque reading right as you tighten it while it's turning. I personally don't own a click type torque wrench any more - for just the reason you list. Plus I don't like to be guessing if it's still calibrated or not. A beam type wrench will be close to it's original calibration unless the surface of the beam gets nicked, gouged, rusted, etc. or the pointer gets bent. I always zero the pointer (bend the thing!) before using it, or just adjust my torque reading to compensate if it's just a bit off. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 5, 2006 Share Posted December 5, 2006 Dr_hunt - you're talking about the difference between static and dynamic friction. If the bolt is tight enough that you can't break the static friction of the threads/bolthead/head interfaces, then you'd never know that the torque while turning the fastener is actually lower then where you are statically. A bolt that isn't turning and has 65 ftlbs of torque on it's head will probably be less stretched (and impart less clamping force, what we should care about) than a bolt that is brought to 65 ftlbs of torque while it's turning. To let it turn while you tighten it, you need to loosen it a bit. I wouldn't loosen it much though! Just enough to let the bolt turn to get the torque reading right as you tighten it while it's turning. I personally don't own a click type torque wrench any more - for just the reason you list. Plus I don't like to be guessing if it's still calibrated or not. A beam type wrench will be close to it's original calibration unless the surface of the beam gets nicked, gouged, rusted, etc. or the pointer gets bent. I always zero the pointer (bend the thing!) before using it, or just adjust my torque reading to compensate if it's just a bit off. Your correct on the static and dynamic. Also a lot of old skool guys still use the beam wrenches. I've never found where + or - 2 to 3lb-ft ever made a difference. Kind of a preference I guess. Although I did see a kid once use an impact gun to do the rods and mains! Didn't live that long, wonder why? Quote Link to comment Share on other sites More sharing options...
v80z Posted December 5, 2006 Author Share Posted December 5, 2006 This is a fairly fresh assembly and I did chase the threads and sealed the stud threads. I also went to a head stud kit and am using fel pro gaskets. Another interesting observation was that I saw vapor bubles, albeit very small and slow, coming up from between the nut of the head stud and the stud it self. Bubbling the oil. Smalll and slow one bubble every 5-6 seconds. Not sure if it is compression air or water. It does not appear to be steam/water. I did a cursory torque check of #1 in the pattern and it moved somewhat on 65 lbs. So I will loosen slightly and the retorque all in steps. If it doesnt work I will replace and check the head deck for flatness. Quote Link to comment Share on other sites More sharing options...
Guest V8Z Posted December 8, 2006 Share Posted December 8, 2006 I always use teflon paste on the headbolt threads to seal it up and a little 10w on the head bolt were it touches the head to reduse friction during torque down. Just something I seen my dad do in the shop. Quote Link to comment Share on other sites More sharing options...
Ledphoot Posted December 8, 2006 Share Posted December 8, 2006 I use victor gaskets on lower compression motors 8.5-9.5 If I'm building more than that I use good Teflon coated brands, spray em with copper, add 5 lbs extra torque and roll! In 25 yrs I've never had an engine failure related to headbolts or head gaskets... If I'm going over 12 to 1 thats a whole different story... I o-ring those. Quote Link to comment Share on other sites More sharing options...
v80z Posted December 11, 2006 Author Share Posted December 11, 2006 Ok after blowing air into #1 cylinder it looks like it is just the exhaust manifold gasket. Thanks for all the help. Quote Link to comment Share on other sites More sharing options...
Guest QuantumDragon Posted December 11, 2006 Share Posted December 11, 2006 No you don't untorque head studs to "retorque" them and yes it is very common. I can't say about LS/LT motors but I've done plenty of others and the only ones that didn't require a retorque, especially with ARP bolts/studs, is a Subaru which had a different material to avoid this since they are a PITA to get to. 1/4 to 1/2 inch extra on some of them is common. Don't freak out, sometimes they creak, crack or squeal when retorquing. Just be carefull and have a good torque wrench. The head gaskets are very doubtful. They usually have a rubberized coating around the holes to protect them from the liquids but the rest of the gasket (where the fluids got) do not. I think you will be pulling heads to redo them. That's what I've seen on every other car when it happens; including full metal multilayer gaskets. Mark Quote Link to comment Share on other sites More sharing options...
280Z28 Posted December 15, 2006 Share Posted December 15, 2006 LS1 heads use a special tightening procedure and you will likely be heli-coiling a block if you don't follow it... Outlined at the bottom below "Optional Cam Swap": http://www.ls1howto.com/index.php?article=3 Obviously this only applies if you have an LS1. Quote Link to comment Share on other sites More sharing options...
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