can i re-torque stock head bolts
 

so my head gasket is in excellent condition (engine only has 51,000 mi) and i was wondering if i could just go in and tighten the head bolts down to 75ft/lbs instead of leaving at 58ft/lbs or whatever toyota had it at stock. i want to know if this is ok to do because if it is ill do that and not have to worry about getting a new hg before im actually wanting to rebuild it.

any help is fantastic

There are two negative factors to retorquing after so long... I'm going off memory here so forgive me if either isn't completely accurate. The first is that the jackets may have hardened and could be compromised; I don't think this is very likely. And the other is that now that the bolts have sat in place for so long you're not going to get an accurate torque value for each and may not get them uniformly tightened or you may not even be able to tighten them due to artificially high readings from seizing.

Now, with that out of the way, I think you're fine to do it. Just crack each bolt loose in the correct order by 1/4 of a turn and tighten them in order in multiple passes.

Do keep in mind that it is possible that whoever did the HG last did use a higher torque level... don't go higher just because...

ok and i have never built a 7mgte only honda b16's so is there a specific bolt pattern thati should follow when tightening them and visa versa for loosening??

Yes, there is an order and it is critical.

Here's the service manual's complete section on the head and related work: http://www.cygnusx1.net/Supra/Librar...ection=EM&P=32
Pay attention to all torque values.

The third image down shows the order for removing/loosening the bolts. Use the opposite order for tightening.

oh and is there any risk of the head bolts sheering off because theyre kinda old?

oh and thanx

I would be flat out amazed if that happened. Worst thing I've ever seen is people stripping the sockets out from not ensuring the driver was in all the way. The stock head bolts are VERY robust.

thank you so so much for your help. youve always helped me quite a bit.
and would you mind replying to my thread about removing the fenders front lip and bumper? if you search fender removal it should be right at the top

oh thanks again for all your help

If I had much to offer on the fender removal I'd gladly offer it up. I'll think it over and post back anything that I can think of which isn't obvious.



Would you mind please posting MKIII specific threads in the MKIII section? Some of the folks there may have worked on the fender more recently than I, for example and they may be more likely to see your post there.
Thanks.

you can reuse your head bolts as long as there not pitted

to retorque your head back each bolt off about a quarter of

a turn before you retension it, make sure you drop the coolant first

you will find an engine drain bung at the back of the block behind the

turbo,

i had a head gasket start to leak on my old NA motor about 1500 Ks

from home, retorqued it out the back of a servo & ended up putting

about another 50K on it while i built the turbo engine

ps dont use your tension wrench to back bolts off !

Stretch is the primary concern (the TSRM has details on measuring the bolts to determine if they're healthy). Sure, if they're pitted, cracked, flaking, etc. you don't want to reuse them. You can't check either without pulling them and compromising the HG so it's a moot point in this discussion.

A re-torque usually won't last long if the HG has already started leaking... the longer it leaks the more the gasket material is subject to erosion. Catching it before it happens is key.