| [ Total Views: 499 | Total Replies: 6 | Thread Id: 8034 ] |
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 de_ja_vu
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| posted on July 1st, 2003 at 05:10 PM |
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cylinder head torquing
hello,
is there any way that over torquing the cylinder head can cause the engine to overheat ? or as long as the case stud will pull out it's ok...?
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 vw54
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| posted on July 1st, 2003 at 05:43 PM |
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Whats do you mean by this ???
| Quote: |
or as long as the case stud will pull out it's ok...?
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Overheating has nothing to do with the torquing of the cylinder head , unless its not sitting even on the barrell???
Do you know how to rebuild an Engine ???
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70AutoStik
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| posted on July 1st, 2003 at 09:25 PM |
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Be nice VW54. What makes this site great is people helping and encouraging others - very few of us are highly qualified and experienced mechanics.
Incorrect torqueing of the head bolts - either using the wrong pattern or torque can certainly cause problems. But they are usually leakage, breaking
or cracking of the head. The one of these that might possibly cause overheating is a crack in the head, but this would usually take some time before
such a problem was apparent.
If you are thinking that you are causing overheating due to incrased CR from over-torqueing, this would not be the case. Any increase in CR from
over-torqueing would be negligible, and the stretch you would cause in the studs by taking them past their "elastic" range would quickly
negate it - you'll actually end up with less tension on the barrell/head interface!
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de_ja_vu
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 posted on July 1st, 2003 at 10:03 PM |
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oopss
i don't really know how to rebuild an engine, but i am trying to figure out those stuff on my own by collecting as much information as i can from
the net, haynes books etc..
anyway, thank you both...
i meant to say : "as long as the case stud will not pull it'll be ok"
i was thinking that over-torqueing is ok as long as i don't pass the point where it's becoming dangerous to the case stud...
but than i thought that it can cause an overheating because of an increased compression ratio, but if you are saying it's not an issue, than
i'll take your word for it...
vw54 - sorry for the confusion, no need to be upset...
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Phil74Camper
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| posted on July 2nd, 2003 at 11:55 PM |
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Welcome to the forum!
When you rebuild an engine, a common precaution is to take the case to a VW workshop to have 'case savers' fitted. These are like helicoils.
They are a little larger than the studs, and 'bite' into the case better.l The studs are then screwed and Loctited into the case savers.
VW recommends tightening the head nuts to around 23 ft lbs - you do it in several steps. There is a pattern you have to follow, and your VW workshop
manual will have little diagrams. You tighten the nuts in several stages to about 10 ft lbs (I like to do both heads at the same time), then to 23 ft
lbs with a different pattern. I like to go over each pattern, on each head, in 5 ft lb increments.
You can probably go to 25-26 ft lbs with no problems, but any tighter than that is not a good idea. Stay with what VW tells you in the manual - they
designed the engine after all.
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vw54
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| posted on July 3rd, 2003 at 07:28 AM |
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No not upset never upset just trying to clarify question.
As Autostick said you wont be able to overtighten the studs as they will most proberly pull out of the soft ally first.
When building a VW engine theres a lot of little tricks that have to be done otherwise you end up with a leaker.
Let me know if i can help again. Follow the steps above and there wont be any probs
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helbus
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| posted on July 3rd, 2003 at 08:53 PM |
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I agree. Follow the manual. I had BOTH the Gregory's and John Muirs Idiots book, as the Gregory's had better pics and the Muirs was easier
to follow in some ways.
I a mechanical dud like me can build a motor, anyone can.
I suppose time will tell, but motor has done 10,000 so far 
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70AutoStik
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| posted on July 3rd, 2003 at 11:31 PM |
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...and Ben has built a lot of engines, that have done a lot of miles.
Just to clarify: Over-torqueing will not improve anything and will probably make for more problems. I know you'll read articles on
engine-building where they use higher than stock torque, but these are race engines designed for a very short life and usually using exotic
materials.
P.S. 8mm studs are essential for the larger cylinder sizes and are recommended by pretty much every reputable engine builder for any engine.
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