Torque Question

[StanleyLyta]

I recently had my E21 head re-built (for the second time in it's 200,000 mile plus existence). The shop took very little off the bottom and told me I was on the cusp on having to run a thicker head gasket...I decided to.

I installed an Elring 1.8mm gasket.

I torqued it down in sequence and in steps to 54 ft/lbs going off my manuals. In my excitement to install I forgot to look at the directions that came along with the gasket...duh Those directions were to torque it to 46 ft/lbs, wait 15 min then 30-36 degree angle torque, then warm, let cool, then another 20-30 degree torque.

My question is:

I torqued to 54 ft/lbs and have not tightened it any more and have not run the car yet. If I leave it be do you think it will be fine, or should I pull the head, get new bolts and gasket and start over?

[Napes]

See if there's any contact info on the directions that came with the gasket and see if you can get some advise from Elring on how to best proceed. I don't think you've ruined anything, and, if nothing else, you sure don't need to replace the head bolts.

Bob Napier

[Pamola]

It actually seems to me that the torque on thoes bolts is less than that the target final torque target is. The science of head bolts is super intresting stuff as you are tring to get to a certian clamp load but the only way to know what the actual clamp load is, is to measure the bolt streach (or strain) which is not really a thing most people will do. Anyway if it was my money in your boat I would untorque everything (with the proper sequence) and give it another go. I bet you a sandwitch that everything is fine.

sorry my spelling is crap and the checker is not working...sigh

[02for2]

It actually seems to me that the torque on thoes bolts is less than that the target final torque target is. The science of head bolts is super intresting stuff as you are tring to get to a certian clamp load but the only way to know what the actual clamp load is, is to measure the bolt streach (or strain) which is not really a thing most people will do. Anyway if it was my money in your boat I would untorque everything (with the proper sequence) and give it another go. I bet you a sandwitch that everything is fine.

sorry my spelling is crap and the checker is not working...sigh

+1

Cheers!

[TobyB]

...and I would simply get it nice and warm, let it cool, and torque everything

to about 60 ft/lbs.

Then retorque after 200 or so miles, again to 60 ft/lbs.

The problem is that the gasket's designed to be 'stepped' and

once you start the process, it doesn't go back to the beginning

even if you do.

you'll be fine this way. I've done it, too, before I learned what all

those little symbols on the gasket instructions meant.

(oh, if ALL you've done is torqued the head, yeah, sure, spend the $25 on a

new gasket. If the car's back together, just torque it. It WILL be OK.)

Yes, it's science, and like all science, you get to interpret it your own way.

Whatever you do, you don't need new bolts. The TTY on those things is

something like 150ft/lbs at the head, and you'll never do that. They're

NOT torque- to- deform bolts like a VW or M20. If they're in decent shape,

they'll hold the head on your car just fine.

I reuse the bolts on the race car all the time. And I torque them to the

high end of believable sanity. And they hold just fine.

t

[c.d.iesel]

..."54 ft/lbs going off my manuals....I forgot to look

at the directions that came with the gasket...duh

those directions were torque it to 46 ft/lbs,

wait 15 min then 30-36 degree angle torque,

then warm, let cool, then another 20-30 degree torque".....

your 54 did not equal the total tightening

of the sequence that you should have performed.

looks like you should start again with another gasket

[TobyB]

..says the man who doesn't own one...

CD and I disagree about many things.

This is one of those things...

If the car's back together, it doesn't cost you much- if anything at all-

to try it. It's not going to blow. If you retorque it twice as I said above,

you'll be in the same ballpark as the manufacturer wanted, and for a modern

gasket, that's good enough.

I've put on a couple dozen of these things, and if you follow the angle

method, you usually end up with a final torque in the region of 60 ft/lbs.

And when you take them off, they're usually around 50. If you take off

one that's been torqued to 54 and never retorqued, it'll be in the region of

40, BUT the bolts will be less even. Some may be as low as 20. Thus, the retorque.

If you're really freaked, sure, change it. But it's a lot of work to replace something that has about a 98% chance of lasting as long as it would have

had you followed the directions that came with the gasket.

IF you retorque it as above.

If you didn't use motor oil on the bolt threads, though, I take it ALL back!

jus' sayin'...

t

[Pamola]

I've put on a couple dozen of these things, and if you follow the angle

method, you usually end up with a final torque in the region of 60 ft/lbs.

And when you take them off, they're usually around 50. If you take off

one that's been torqued to 54 and never retorqued, it'll be in the region of

40, BUT the bolts will be less even. Some may be as low as 20. Thus, the retorque.

If you're really freaked, sure, change it. But it's a lot of work to replace something that has about a 98% chance of lasting as long as it would have

had you followed the directions that came with the gasket.

IF you retorque it as above.

If you didn't use motor oil on the bolt threads, though, I take it ALL back!

jus' sayin'...

t

Agreed. I've reused (ok ok metal 3 ply) gaskets that have been in an engine that ran for a brief amount of time (on a dyno doing power tests) and never had a problem. As for the motor oil on the bolt threads use a thin complete coating of the best stuff you have otherwise the initial torque setting will be wrong.

[02for2]

Agreed. I've reused (ok ok metal 3 ply) gaskets that have been in an engine that ran for a brief amount of time (on a dyno doing power tests) and never had a problem. As for the motor oil on the bolt threads use a thin complete coating of the best stuff you have otherwise the initial torque setting will be wrong.

REALLY.. ??

Motor OIl.. ??

All Torque Specs assume a Dry Thread unless specifically noted.. !!

Cheers!

[StanleyLyta]

I did oil the threads and bottom of the washers (it did state this on gasket directions - the step I did follow).

I think I'm going to just warm the car, torque it up and not change out the gasket. Does it matter that it's a thicker gasket though?

[eugene_'02]

doesn't matter that it's a thicker gasket. Always lube the threads with oil(clean out the holes before inserting the bolts), torquing against dry metal means your going to end up with a higher kinetic friction. It's possible the bolt will only be providing 40lbs of clamping force when the torque wrench is clicking off at 54.

[StanleyLyta]

Thanks for all the input.

[c.d.iesel]

.."does it matter that it's a thicker gasket though?"

not at this point

what the hell - just give all the bolts another 25.. 35 degrees

[TobyB]

See, NOW we're on the same page, CD!

Motor OIl.. ??

All Torque Specs assume a Dry Thread unless specifically noted.. !!

Cheers!

...and head bolts for the BMW 2002 are specifically called out to be oiled.

There you go.

(in fact, if you don't oil a steel bolt into a grey or nodular cast- iron casting, your life will suck.

The no- oil thing assumes like metals, as in, the bolt and nut are both steel.)

t