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M20 stretch head bolt question SOT


ahlem

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Pretend for a minute I'm doing an M20B25 swap into my 2002 and I take the head off and refurbish it and reinstall it with new stretch bolts. I put the motor in and run it for 5K miles. Am I supposed to retorque the headbolts? I need to do something because I'm getting oil leakage between 3 and 4 on the exhaust side. Compression is good and the head and deck were checked for flatness. I did notice that funny feeling when the torque wrench hit the specified setting and the bolt stretched. I then turned the bolts the prescribed additional angle(s). There is a discussion on the e30 sites regarding the quality of the Victor R. head gasket and this exact problem. Yes, I did search.

Ahlem

'76 2002

'90 M3

'90 535i 5 speed

'89 325is '91 318is

'87 325is

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Pretend for a minute I'm doing an M20B25 swap into my 2002 and I take the head off and refurbish it and reinstall it with new stretch bolts. I put the motor in and run it for 5K miles. Am I supposed to retorque the headbolts? I need to do something because I'm getting oil leakage between 3 and 4 on the exhaust side. Compression is good and the head and deck were checked for flatness. I did notice that funny feeling when the torque wrench hit the specified setting and the bolt stretched. I then turned the bolts the prescribed additional angle(s). There is a discussion on the e30 sites regarding the quality of the Victor R. head gasket and this exact problem. Yes, I did search.

The answer is no.

It is difficult to speculate why you have a leak. Were the threaded holes in the block cleaned and chased? Were the bolt threads lubricated? Did a piece of dirt get lodged between the gasket and the head or block? Did you forget your locating dowels? Is the gasket defective?

Tightening the bolt can cause it to snap. Most likely, the leak won't stop anyway even if you manage not to break the bolt. If the leak is bad, and this is a car you plan to keep, the head has to come off. Yes, you will need a new gasket and new bolts.

Let us know what you do and the outcome.

Pierre

O==00==O

69 2002 (M20), 74 tii, 76 533i, 79 323i, 80 732i, 84 323i (S50) 91 318is, 96 318ti (S52), 97 Z3, 02 330i, 03 525iT, 02 R1150 RTP.
Auxiliary Lamp Brackets  Kamei Reproduction Front Air Dam

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The Victor Reinz gaskets are the suspect. On the e30 sites they get bashed all the time. Everything was clean and properly done and checked. This was my first foray into stretch headbolts so I was looking for feedback from a reasonably knowledgeable group, unlike some forums where the "mouth" engages before the brain.

Ahlem

'76 2002

'90 M3

'90 535i 5 speed

'89 325is '91 318is

'87 325is

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Try it again meaning replace the headgasket and the bolts or just the bolts? I read a procedure somewhere where you would change one bolt at a time and then do the additional degree torqueing after all were swapped. Please clarify. Thank you.

Ahlem

'76 2002

'90 M3

'90 535i 5 speed

'89 325is '91 318is

'87 325is

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When you re-do that job, make absolutely sure that the bolt-holes are not partially filled with grease or oil and do not use any moly or other extreme-pressure grease to lubricate the threads.

Using extreme-pressure lubricants will over-tighten and sometimes break or overstretch the bolts or studs.

No amount of skill or education will ever replace dumb luck
1971 2002 (much modified rocket),  1987 635CSI (beauty),  

2000 323i,  1996 Silverado Pickup (very useful)

Too many cars.

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