What happens? I read the tq setting from a different item and over torqued the head bolts to 50 when they should’ve been 33.
the bolts are fine, grade 12.9 and rated to handle ~75 lbs via my google-fu
I’m worried about the gasket though, is it done for since it was squished by almost double? Or am I still good?
Head gaskets only need 33ft/lbs? seems low to me. Don't know what bad things if any will happen. If you are worried about it how much is a gasket compared to another tear down after it is all back together and running?
Yeah, 33 seems REALLY low. I just put the head back on the Monster and the machine shop guru told me to torque to 70 ft/lbs.
KyAllroad (Jeremy) said:Yeah, 33 seems REALLY low. I just put the head back on the Monster and the machine shop guru told me to torque to 70 ft/lbs.
I agree, I'd be worried to only torque them to 33.
Depends on the car you are doing it to. Mk3 supras left the factory under torqued.
And it is not TTY? 33 lbs and 3/4s of a turn?
ALL OF THE BOOST!
Is the correct answer.
Trackmouse said:Depends on the car you are doing it to. Mk3 supras left the factory under torqued.
I was just thinking "33ft-lbs? What the hell is he working on? 7M-GTE?"
If they're TTY bolts (and if we're talking about the Focus, then I think they are) and instead of going to 30 ftlbs and then turning x degrees you just went straight to 50 ftlbs then maybe they stretched enough and maybe they didn't? Having just gone through the process of improperly seating a head gasket and having to do it all a second time, I would go ahead and toss those bolts, get a new gasket and new bolts, and do it again. It might be fine the way it is, but it might not.
If this isn't a TTY situation then I would guess that as long as you didn't crack or snap anything and you gave them all 50 ftlbs, I'd probably just go with it. But I am neither a professional nor did I stay in a Holiday Inn Express last night...
Is that an interim step before final torque?
What is the diameter of the bolt?
LOL focus is non-turbo again. damn Germans make it hard to do! also, blew up the motor...
its a 78 opel ascona B. ive posted it up here before, this is my go to place to ask q's if i haven't got a clue as to what im doing; but... i do remember 33 ft-lbs. final tq
From 33 to 50 ft. lbs is about 3/4 turn and to me that is at the bottom of where I would leave them . You may have Felt a Give as it approached the 50 number, If it didn't I would check at 55 to feel for Bolt Give .
If it's a 12.9 bolt then you should be fine. The bolt can take it and the gasket should be able to as well.
I've sold thousands of similar head bolts for a particular application and the end user often over torqued them as the OEM spec also seemed low. To my knowledge nobody ever had an issue.
Drive it. The only thing that happens if you really overtighten is the bolt or threads fail. If it torqued down nicely, no problem. If it felt like you were torquing silly putty, change the bolts.
If it's aluminum then it's possible to crack the head by overtorquing head bolts. That would probably have manifested by now, though.
I'm paranoid -- if it were me, I'd go back and redo it to the correct spec.
over-tq'd like i did? or like another 10-lbs?
bolts did begin to give, i stopped before they did. thats when i realized my dumb mistake. im sure 12.9 is fine if a little yielded at 33lbs, but they are 40-yr old 12.9's
i'm not expert enough to know how far into yielding they were. 10%? 90%? not a clue
In reply to codrus :
this is 70's cheapo GM euro-... equip. cool car but its heavy like its iron, not light like aluminum. put 2 and 2 together and i think its safe to assume its iron and fine.
im paranoid to LOL. redone to proper spec, and asking on here. ive been hunting down an overheating problem, turned out to be a head gasket like i thought.
did all this work, screwed up but im trying to figure out if this is the reason it still gets hot.
If the threads didn't pull out of the block, I wouldn't worry too much about it. If it was an aluminum head and iron block, you may experience early head gasket failure since the head wouldn't be able to "float" sideways on the block as easily. (Sounds weird, doesn't it?) In theory.
I've seen hacks zip down head bolts with a 3/8" impact because they didn't feel like doing the head torque rigamarole on TTY bolts on a V6 minivan... and the world didn't end. Sometimes good enough really IS good enough. (Not that I would rely on that...)
I'd be more worried that the head or block were sunk in between those two cylinders.
well its coming back off, can report if there's interest
TurboFocus said:well its coming back off, can report if there's interest
Follow up is always welcome
What vehicle/engine is this for? 33 lb-ft seems too low for any head bolt ever...
Edit: For reference most M12 head bolts are something like 40-50lbft then 90 degrees.
A brief google search suggests the 33 number might be real. I'd need to know the bolt diameter to figure out how worried id be about 50 lb ft on it.
The case I know of people cracking aluminum heads is on Miatas, when using the ARP uprated head bolts which were at one point shipped with an incorrect torque spec that was too high by a lot. At least one person reported cracking the head trying to meet that spec.
you may not need a new Gasket they are Cheap ,But Really get new bolts they are Cheap Insurance.
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