Should I overtighten to other head bolts too??

[Old Henry]

Stupid me! I have accidently overtightened the head bolts on one end of one head. I don't know by how much. My options:

1. Don't worry about it and do nothing.

2. Overtighten the other bolts to match the overtightened ones.

3. Loosen the overtightened bolts back to specs.

What should I do?

[trainguy]

If within 5# let it alone.If more I would loosen them all just below spec. and retorque them acording to the sequence chart.45-50 ft#Phil

[Craig CT]

Hi Old Henry; There's a procedure for this, starting in the middle and working outward tightening in increments. I'd loosen the tight ones and start over. Check a manual for the sequence, Craig.

[flatjack9]

Leave them alone.

[Old Henry]

Originally Posted by Craig CT

Hi Old Henry; There's a procedure for this, starting in the middle and working outward tightening in increments. I'd loosen the tight ones and start over. Check a manual for the sequence, Craig.

Can someone post the procedure?
Since I don't know how overtight some are I'd rather start over and get it right before I take this car to Yellowstone and Canada next week.

[Mike in AZ]

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here's a link to MacVP's website showing torque values and sequences....Mike

http://www.vanpeltsales.com/FH_web/f...rque-specs.htm

[Kube]

If you over tightened them quite a bit you may have very well crushed the gasket in that area more than the adjacent area. To back the nuts off and torque them to the correct specification may be detrimental in that area.
You can use a torque wrench on the ones you overtightened to figure out how hard they are down. Simply clock your wrench at the correct specification and increase that clock by 2# until the wrench releases.
If you are close, leave it alone.
You can always torque down any cylinder head without a chart depicting the suggested pattern. Always torque down in a minimum of two steps. 10# between the first and second step.
Always start at the middle of the head and work outwardly. Try to imagine you are stretching the head while torquing it down. Obviously you do not want to "capture" the outer edge thereby not allowing it (the head) to "stretch".

[cuzncletus]

I've been scared to post this for fear of ridicule, but this might be the right time. I had an old engine builder tell me the secret of keeping aluminum heads tight was to not torque them in sequence but to torque them from back to front. Any truth in this?

[flatjack9]

I think Edelbrock recommends this sequence with their heads. I see no problem with this as long as it is done in steps as previouly mentioned.

[Ross F-1]

After the first run they'll likely all be back down around 40 ft-lbs. I agree with leaving them alone unless you went up to 100 ft-lbs or something extreme like that, in which case you should probably put in a new gasket and start over.

[jackson]

Cuz, for what it's worth..... the instructions that came with my Offy aluminum heads stated (with emphasis) to tighten in incremental steps from one end to the other (rather than from the center out) ..... topping out at 45# max. torque.

[cuzncletus]

Thanks. I'm glad I asked.

[1949FORD]

Originally Posted by Old Henry

Can someone post the procedure?
Since I don't know how overtight some are I'd rather start over and get it right before I take this car to Yellowstone and Canada next week.

I believe that would be the best thing to do is to start over. just to be safe!

[oldford2]

Professor,
You did not say how you "over tightened" the head bolts. Were you using a torque wrench? Gotta get that buggy ready for the "adventure".
John

[Old Henry]

Originally Posted by oldford2

Professor,
You did not say how you "over tightened" the head bolts. Were you using a torque wrench? Gotta get that buggy ready for the "adventure".
John

I was afraid someone might ask.

This was the second re-torque after just having my engine rebuilt and a couple of long drives. The first re-torque seemed to go OK. When the bolts were tight enough I heard this nice loud click of the wrench (I rented from AutoZone). But this second time I started on the left side of the engine - all went well. Then on the right side. I started with the higher nuts I could get to with a long extension on the wrench. I could hear the nice loud click each time. But, to get the nuts down under the battery I had to just put the socket right on the wrench. As soon as I put the slightest pressure on the wrench I heard a very faint click that was nothing like I was used to. I didn't think that was the click I was waiting for so I just kept tightening. Finally I figured "Something is wrong here. These nuts couldn't be that loose." I then suspected that the very faint clicks I was hearing was, in fact, the wrench clicking the same as before but not amplified by the extension. So, I tried the socket and wrench only without any extension on the higher nuts on which I'd heard the loud click with the extension on and it was the same very faint click I'd heard on those low crowded nuts without the extension. So, there you have it.

I know I'm not going to remove the head and replace the gasket to start all over. I'm probably going to go with Kube's suggestion to torque the other bolts down to what the tighter ones are just so's everything's equal and I don't risk a loose head on a crushed gasket.

As I've searched for recommended torque values on here I've seen everything from 40-75 ft/lbs. Doc Roger said 55 so I was aiming for that but apparently a little more won't hurt as long as it's all equal. At least I hope so since that's what I'm doing.

[Ol' Ron]

I don't think it would hurt to run the engine for a few underd miles and re torque the heads. As for the sequence, I just start in thr middle and work out at 25, 35, and 45. I also use used gaskets if the y look good. I don;t think it matters much, nobody seems to follow the same rules anyway and the old flathead just keeps on runnin.

[Karl Wolf]

Originally Posted by trainguy

If within 5# let it alone.If more I would loosen them all just below spec. and retorque them acording to the sequence chart.45-50 ft#Phil

I'm with Train Guy...

The general rule I use in terms of a pattern is to start at center and use a clockwise pattern- go in an expanding circle to both ends.
When I retorque, I start each bolt by letting the tension off- loosening- then taking it back up to the value I am looking for...

On one engine with new gaskets, I retorqued all of one head, made pencil marks where the nuts settled, went back and did it again, this time loosening them first- (One by one) and got an average of 20 degrees more turn on the nuts.

If you start at the front end, you will crush the gasket at the front, and as you work to the other end, be lifting the front of the head off of the gasket as the head is using the uncrushed gasket as a fulcrumb as you increase the pressure on the already tightened bolts.

In my opinion...
Karl

[JWL]

I strongly disagree with making them all the same if they are over tightened. Much better to loosen and restart. Here is why:---the block deck is much better supported in some areas than others. The basic method for good gasket life is to keep everything as flat as possible. In several areas the head is stronger than the block deck. Overtightening all fasteners to a higher value results in the deck pulling up and increasing the crush of the gasket in some areas which will likely lead to longer term gasket failure. This is especially noticable between the cylinders 1-2, 3-4, 5-6, 7-8. Those of you who have examined Flathead blocks know they are nearly always cracked in the mentioned areas from threaded hole to water hole. The reason is simple---there is little support(in others words it is weaker) and the deck can easily be pulled out-of-flat by using more than 45 ft. lbs. with properly lubed fasteners. Pulling all the fasteners to higher torque sounds good but results in an uneven deck and gaskets with thick and thin areas.

If the gaskets have already been destroyed by over-tightening in a small area(which I doubt) it will be necessary to start with new gaskets. If the over-tightening has been minimal it might be alright to set all values at the correct level and continue the process of heat-cool cycles and re-tightening to maintain proper flatness.

[Bluebell]

JWL knows what he is talking about.
What sort of gasket have you used?
If it happens to be a Copper asbestos type you can take it off and soak it in water. (it will swell up)and you could re-use it.

Other than that I would back them off half a turn and re-torque as per specs.

The flathead is known to have a weak top deck. Treat it with respect or you will shortly be dealing with bigger problems.

[Old Henry]

Originally Posted by Kube

If you over tightened them quite a bit you may have very well crushed the gasket in that area more than the adjacent area. To back the nuts off and torque them to the correct specification may be detrimental in that area.

Originally Posted by JWL

I strongly disagree with making them all the same if they are over tightened. Much better to loosen and restart. Here is why:---the block deck is much better supported in some areas than others. The basic method for good gasket life is to keep everything as flat as possible. In several areas the head is stronger than the block deck. Overtightening all fasteners to a higher value results in the deck pulling up and increasing the crush of the gasket in some areas which will likely lead to longer term gasket failure. This is especially noticable between the cylinders 1-2, 3-4, 5-6, 7-8. Those of you who have examined Flathead blocks know they are nearly always cracked in the mentioned areas from threaded hole to water hole. The reason is simple---there is little support(in others words it is weaker) and the deck can easily be pulled out-of-flat by using more than 45 ft. lbs. with properly lubed fasteners. Pulling all the fasteners to higher torque sounds good but results in an uneven deck and gaskets with thick and thin areas.

Originally Posted by Ol' Ron

. . . I don;t think it matters much, nobody seems to follow the same rules anyway and the old flathead just keeps on runnin.

Very interesting.

I went with Kube's suggestion to torque the looser bolts to the tighter bolt torque working from the end where the bolts were already overtight toward the other end. Went from 55 ft/lbs to 61 ft/lbs.

Now I'm starting to believe Old Ron really has the right idea - it's really not as critical as some seem to believe and preach. I certainly hope so because we leave for Canada first thing in the morning on a 1,800 mile round trip. I think that, even if something fails, we would still never know whether it was because the bolts were too tight. Hope I never have to try to figure that out.

(Rabbi, is there a prayer for a road trip??)