Replace Head Studs?
06-21-2010, 08:23 PM
#76
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Thread Starter
Yes, except not "like" stud and bearing mount". It is "stud and bearing mount"...and they used plenty. One could soak those things in a vat of Pb Blaster until the cows come home and that will not help.
06-21-2010, 09:22 PM
#78
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The '83 that I'm having problems with is an absolute "virgin" with just over 100,000 miles. Never had the heads touched.
Although everyone seems to be attracted to the uber low mileage vehicles, most of the ones I've seen have head gasket issues (even late model GTS vehicles). Seems that most cars that sat/had little use also didn't get their coolant changed. The coolant turned acidic after a couple of years and just sat there and "ate" at the gaskets/hardware/aluminum. Many years ago, I actually had an early car that literally "ate" the cylinder liners and the heads away. Had to find another engine...it was junk.
I did a pre-purchase on a fairly nice, low mileage early car, a week or so ago. It had leaking head gaskets...all the way around. Tough to tell both the current owner and the potential buyer that this can be a real bag of worms...they just don't understand the extent of the problem.
Although everyone seems to be attracted to the uber low mileage vehicles, most of the ones I've seen have head gasket issues (even late model GTS vehicles). Seems that most cars that sat/had little use also didn't get their coolant changed. The coolant turned acidic after a couple of years and just sat there and "ate" at the gaskets/hardware/aluminum. Many years ago, I actually had an early car that literally "ate" the cylinder liners and the heads away. Had to find another engine...it was junk.
I did a pre-purchase on a fairly nice, low mileage early car, a week or so ago. It had leaking head gaskets...all the way around. Tough to tell both the current owner and the potential buyer that this can be a real bag of worms...they just don't understand the extent of the problem.
I understand why you'd replace these studs/bolts .... because of all the corrosion and the leaking gaskets ... and why you'd be a bit nervous about the outcome even with new studs, because everything else has been compromised.
My motor has no corrosion at all, original gaskets were a bit rotten but still totally leak free, and my studs look fine with no corrosion of the block threads ..... do I replace them or use again? I'm hesitant because I've re-used head studs/bolts (where there were no other problems) on race, rally and road cars before with no problems. If these studs are often unreliable ... then I won't hesitate to replace them.
Just trying to get my head around all this and figure how good the studs are on a motor that doesn't have all the other nightmare problems that would compromise the ability of the stud/bolt function as well.
06-22-2010, 12:55 AM
#79
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The '83 that I'm having problems with is an absolute "virgin" with just over 100,000 miles. Never had the heads touched.
Seems that most cars that sat/had little use also didn't get their coolant changed. The coolant turned acidic after a couple of years and just sat there and "ate" at the gaskets/hardware/aluminum. Many years ago, I actually had an early car that literally "ate" the cylinder liners and the heads away. Had to find another engine...it was junk.
Seems that most cars that sat/had little use also didn't get their coolant changed. The coolant turned acidic after a couple of years and just sat there and "ate" at the gaskets/hardware/aluminum. Many years ago, I actually had an early car that literally "ate" the cylinder liners and the heads away. Had to find another engine...it was junk.
My question: if i do empty the system and flush with some distilled water or something, would you simply replace with new coolant or leave it dry after flushing? i suppose this is a 'long term storage question' and i haven't searched for that yet on the forum. I know, lazy bum. But i'm thinking it might be relevant here . . .
06-22-2010, 01:27 AM
#80
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I am going to start replacing bolts on all the head jobs we do at the shop, not just on the ones that call for it.
What I am getting out of this is that you can not get the clamping force that the engineers wanted when using old bolts/studs, regardless of the method used to tighten them, IE simple torque or torque plus degrees.
I have only had two comebacks on head gaskets in the last 17 years and we have done countless ones, if I had to guess the number is over 200, but I wonder if the two that I did have problems with were related to using old bolts.
One was a Toyota R-22 and the other was a Nissan something that I can not remember, this does not include any kind of supercharged cars with tuning issues, those do not count IMHO.
What I am getting out of this is that you can not get the clamping force that the engineers wanted when using old bolts/studs, regardless of the method used to tighten them, IE simple torque or torque plus degrees.
I have only had two comebacks on head gaskets in the last 17 years and we have done countless ones, if I had to guess the number is over 200, but I wonder if the two that I did have problems with were related to using old bolts.
One was a Toyota R-22 and the other was a Nissan something that I can not remember, this does not include any kind of supercharged cars with tuning issues, those do not count IMHO.
If you've only had that failure rate over all that time, which may not even be related to bolts, maybe you're not having a problem that you need to deal with ????
06-22-2010, 03:56 AM
#81
Team Owner
when your setting the new studs into the block dont use any Loctite primer on the holes or studs , the primer activates the loctite and it will set up before you get the studs screwed down and checked for the correct height.
Use a Mapp gas torch to heat the stud area it gets hotter faster and the aluminum block soaks up the heat
Use a Mapp gas torch to heat the stud area it gets hotter faster and the aluminum block soaks up the heat
06-22-2010, 10:12 AM
#82
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At what it costs me to redo one, plus the lost time from not making money on another job, the tow bill, the customer getting angry, it is just not worth not putting new bolts in all of them.
We had only been replacing torque to yield bolts before.
I went back and found one of them, the R22, it looks like either a radiator came apart from the cooling system being over pressurized or the radiator failed and took the head out.
The other one has been to long ago for me to find.
We had only been replacing torque to yield bolts before.
I went back and found one of them, the R22, it looks like either a radiator came apart from the cooling system being over pressurized or the radiator failed and took the head out.
The other one has been to long ago for me to find.
The answer to that would depend on what you had to do to fix the ongoing problem. If you finally fixed them without replacing the bolts ... then it wasn't the bolts ... if you replaced the bolts to fix, then providing that's all you did, it was definitely the bolts. If you replaced say a gasket and the bolts ... maybe it was the bolts, maybe it was the gasket. Two in over 200, in 17 years, is pretty good considering all the variables thrown at you on every job. Sounds like you must be covering all the bases already ... and making the right individual judgement calls.
If you've only had that failure rate over all that time, which may not even be related to bolts, maybe you're not having a problem that you need to deal with ????
If you've only had that failure rate over all that time, which may not even be related to bolts, maybe you're not having a problem that you need to deal with ????
06-22-2010, 10:37 AM
#83
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At what it costs me to redo one, plus the lost time from not making money on another job, the tow bill, the customer getting angry, it is just not worth not putting new bolts in all of them.
We had only been replacing torque to yield bolts before.
I went back and found one of them, the R22, it looks like either a radiator came apart from the cooling system being over pressurized or the radiator failed and took the head out.
The other one has been to long ago for me to find.
We had only been replacing torque to yield bolts before.
I went back and found one of them, the R22, it looks like either a radiator came apart from the cooling system being over pressurized or the radiator failed and took the head out.
The other one has been to long ago for me to find.
I've replaced the complete set on motors once I've had one torque to yield in the set, as I figured the others might not be far behind. Using that procedure I found I could usually get one reuse and then it went pear shaped ... but I suppose that second use sometimes may have been marginal.
What sort of torque to yield fail rate have you experienced at a guess? Have you ever struck any suspect new ones?
06-22-2010, 11:02 AM
#84
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I can not say that I have ever had a bad torque to yield bolt, or probably more to the point did not know if I did.
We just always replace them after one use, even if some dummy puts the head gasket in upside down and they have to come off before the engine is fired. (yep guilty)
Now we have had a lot of bolts pull out of the block on MB's and BMW's.
We just always replace them after one use, even if some dummy puts the head gasket in upside down and they have to come off before the engine is fired. (yep guilty)
Now we have had a lot of bolts pull out of the block on MB's and BMW's.
That's logical and importantly makes business sense .. any subsequent failure shortly after will very often be your fault in a customers eyes, regardless of what you've done.
I've replaced the complete set on motors once I've had one torque to yield in the set, as I figured the others might not be far behind. Using that procedure I found I could usually get one reuse and then it went pear shaped ... but I suppose that second use sometimes may have been marginal.
What sort of torque to yield fail rate have you experienced at a guess? Have you ever struck any suspect new ones?
I've replaced the complete set on motors once I've had one torque to yield in the set, as I figured the others might not be far behind. Using that procedure I found I could usually get one reuse and then it went pear shaped ... but I suppose that second use sometimes may have been marginal.
What sort of torque to yield fail rate have you experienced at a guess? Have you ever struck any suspect new ones?
06-22-2010, 01:03 PM
#86
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What I am saying is that we normally only replaced the torque to yield bolts, now we are going to replace all of them.
Boosted cars always got new bolts regardless.
I can not say that I have ever had a failure of a headgasket that I can lay the blame just on the bolts.
Replacing the bolts, even the non torque to yield bolts should take one more thing out that may fail.
Any time I use a torque to yield bolt it is a one shot thing, if they need to be taken off for any reason they get replaced.
Does that help at all?
Boosted cars always got new bolts regardless.
I can not say that I have ever had a failure of a headgasket that I can lay the blame just on the bolts.
Replacing the bolts, even the non torque to yield bolts should take one more thing out that may fail.
Any time I use a torque to yield bolt it is a one shot thing, if they need to be taken off for any reason they get replaced.
Does that help at all?
06-22-2010, 05:57 PM
#88
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06-22-2010, 06:02 PM
#89
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Thanks Gregg
I understand why you'd replace these studs/bolts .... because of all the corrosion and the leaking gaskets ... and why you'd be a bit nervous about the outcome even with new studs, because everything else has been compromised.
My motor has no corrosion at all, original gaskets were a bit rotten but still totally leak free, and my studs look fine with no corrosion of the block threads ..... do I replace them or use again? I'm hesitant because I've re-used head studs/bolts (where there were no other problems) on race, rally and road cars before with no problems. If these studs are often unreliable ... then I won't hesitate to replace them.
Just trying to get my head around all this and figure how good the studs are on a motor that doesn't have all the other nightmare problems that would compromise the ability of the stud/bolt function as well.
I understand why you'd replace these studs/bolts .... because of all the corrosion and the leaking gaskets ... and why you'd be a bit nervous about the outcome even with new studs, because everything else has been compromised.
My motor has no corrosion at all, original gaskets were a bit rotten but still totally leak free, and my studs look fine with no corrosion of the block threads ..... do I replace them or use again? I'm hesitant because I've re-used head studs/bolts (where there were no other problems) on race, rally and road cars before with no problems. If these studs are often unreliable ... then I won't hesitate to replace them.
Just trying to get my head around all this and figure how good the studs are on a motor that doesn't have all the other nightmare problems that would compromise the ability of the stud/bolt function as well.
06-22-2010, 06:03 PM
#90
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OK, this is an awesome thread and i have an 83 with just over 115,000. (que twilight movie theme). Purchased about 1.5 years ago, i don't know much of the service history though it does have some small indications (white powdery stuff at the gasket in the valley that the head gaskets are probably due. since i'm going through some transmission work, the car's not running much. this thread is causing me to consider flushing the cooling system to prevent it "going acidic" and turning corrosive which i didn't know it could do.
My question: if i do empty the system and flush with some distilled water or something, would you simply replace with new coolant or leave it dry after flushing? i suppose this is a 'long term storage question' and i haven't searched for that yet on the forum. I know, lazy bum. But i'm thinking it might be relevant here . . .
My question: if i do empty the system and flush with some distilled water or something, would you simply replace with new coolant or leave it dry after flushing? i suppose this is a 'long term storage question' and i haven't searched for that yet on the forum. I know, lazy bum. But i'm thinking it might be relevant here . . .