The 3.0 Hypothesis - if you've had a headgasket fail, read...if you have headers too
Apr 5, 2007 | 05:24 AM
#41
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From: Oklahoma State
He did say this:
Yes, time consuming, but much faster and less costly than another set of gaskets
Apr 5, 2007 | 06:56 AM
#44
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From: TENN Native Languishing in Virginia
TNR - hahahaha I was thinking that myself. (26scfm@90psi...grrrrr!! lol) But Ill bet you after 500 or 1000 miles you'll probably need to check the valve shim clearnaces and that would be a perfect time to retorque. I know my compression is all over the place and ive got a very loud tick in the top end so I definately need to check my clearances....
Mt - does the 1/4 of 100% refer to the 33ftlbs?
Mt - does the 1/4 of 100% refer to the 33ftlbs?
(twisting the knife...grrrr back atcha)I think that meant 1/4 turn every time you reach a yield point (so that would be 3 backoffs total...?)
BUMPIN: Have you stethoscoped your tick yet?
Last edited by TNRabbit; Apr 5, 2007 at 06:58 AM.
Apr 5, 2007 | 07:58 AM
#45
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From: Plainfield, IL
Reusing a TTY bolt will typically result in higher clamping force on the gasket although like not as uniform as before yield.
The effect of stretching the bolt strain hardens it. It still has elastic properties, but it sort has a higher spring rate. You re-torque and again enter yield, you might be putting more clamping force on the head depending on the method. If all the FMS says to do is torque to a certain value, then the force is the same. If it is like the process used on, for example, older Mercedes 5 cyl diesels, you torque like 120ft-lb then turn each bolt one full revolution. In the latter case you would be putting more force on the heads.
As the gasket, threads, etc... settling, there harder bolt will not have as much distance over its range of tensions to relax while maintaining tension.
The bolts will anneal to some degree on the head so it is possible the effects of strain hardening are negated over time.
Frank
The effect of stretching the bolt strain hardens it. It still has elastic properties, but it sort has a higher spring rate. You re-torque and again enter yield, you might be putting more clamping force on the head depending on the method. If all the FMS says to do is torque to a certain value, then the force is the same. If it is like the process used on, for example, older Mercedes 5 cyl diesels, you torque like 120ft-lb then turn each bolt one full revolution. In the latter case you would be putting more force on the heads.
As the gasket, threads, etc... settling, there harder bolt will not have as much distance over its range of tensions to relax while maintaining tension.
The bolts will anneal to some degree on the head so it is possible the effects of strain hardening are negated over time.
Frank
Apr 5, 2007 | 08:32 AM
#46
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From: Sarasota, FL
Nope not yet, hmmmmm that would be a good tool investment! An automotive stethoscope! *runs out the door headed to Harbour Freight or Sears*
Apr 5, 2007 | 09:15 AM
#47
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From: TENN Native Languishing in Virginia
Here ya go, Bump:
http://www.northerntool.com/webapp/w..._385487_385487
http://www.northerntool.com/webapp/w..._385487_385487
Sep 30, 2007 | 08:46 PM
#49
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From: Bay Area CA
You are dead on! The abolishion of asbestos created lots of headgasket issues for other makers also. The 1988 3.0 and 89 and mid way throough 90 used asbestos, we had zero problems with these (keep in mind, a failure rate of about 7% in 100K miles was considered normal, headgasket is kinda like a normal wearing item). The worst gaskets were design 1 from late 1990 to 1993. In 1994, it was improved and 95, final design gasket was used) They have a print seal which was facing upward which made the gasket stick to the aluminum, and float on the iron as it expanded. Well, the aluminum expanded at a greater rate, design 2, same deal, but more reinforcement. Design 3, print seal was moved on the block side of the gasket, and even more reinforcement added which was bascially more steel and the head was allowed to float eliminating deformed gaskets. As for the 3.4, they did use a composition gasket, but around 99, they went to a laminated all steel gasket with a coating to allow slippage, but no gasket distortion. Problem solved.
Oct 1, 2007 | 03:55 AM
#50
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From: TENN Native Languishing in Virginia
Buy from www.engnbldr.com
Oct 1, 2007 | 06:36 AM
#51
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From: Charlotte, NC
While we're on the subject:
Are there any aftermarket head gaskets people have tried? Were they better or worse than the OEM gaskets?
I'm gonna be taking my 4Runner offline over the winter and do a whole slew of maintenance items...with 280K on the clock (and not knowing the prior history), I think it's about time
Are there any aftermarket head gaskets people have tried? Were they better or worse than the OEM gaskets?
I'm gonna be taking my 4Runner offline over the winter and do a whole slew of maintenance items...with 280K on the clock (and not knowing the prior history), I think it's about time
Oct 12, 2007 | 07:20 AM
#54
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From: Richmond , Va / Henrico Co.
Head Gasket Re-Torque
Well which would you rather do ................ Re-Torque or Replace again down the road due to not re-torqing .............It has always been a required step in every engine I have put together to re-torque after bringing up to operating Temp and letting completely cool down and generally almost every bolt needs a adj. according to calibrated torque wrench ..................................The Choice Is Yours 
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