85crewcabbie

I have been replacing the head gasket in my 150K stock truck over the last few weeks. I decided on the incremental torque method after a lot of back and forth. I had left it cold torqued to 100 ft.lbs prior to christmas. I had chased all threads in block and bolts themselves after they passed the drop test as well as oiled the bolt threads and under bolt head. I got it fired up and warmed up a few times and finally retorqued them at 100 ft/lbs hot today. I upped the setting to 110 and snapped two of the short exhaust side bolts. My questions are:

1) would you guys reuse the new (current) gasket or replace it again?

2) Are there any high quality bolt sets out there besides cummins? Not into studs for my stocker.

Thanks for your anticipated help.

Bencie

If you pull the head off do not reuse the gasket. Those broken bolts should not be tight in the holes since you cleaned everything and they don't bottom out in the holes. You should be able to manipulate them out. I would get all new stock bolts and maybe try another torque wrench.

cdennyb

If you're looking for the ultimate bolt set to put in there you could opt for ARP stuff.

sooty

ive had similar problems with other engines, aluminum blocks ripping thread, i talked to my machine shop, and reusing the gasket is ok as long as you get everything cleaned up real good, and gasket condition is good, go back thru your torque procedure and up the torque to the next higher step to complete at 110, ive got mine at 120.

j_martin

If I lift the head, I'd never reuse the head gasket.
1. They squish to seal around the cylinders, and maybe other passages.
2. The labor to replace it is way more than the gasket is worth

Check your wrench. If it's in calibration, replace all the head bolts. They've been over torqued and stretched sometime in their life, and can't be trusted.

If the torque specification is for a dry bolt, you've already over torqued them yourself. When the inclined plane (thread) and mating surfaces (bolt head) are lubricated, it takes considerably less torque to get the same tension on the fastener.

93-12Smoke

J_Martin, the fsm recommends using motor oil on the bolts during install. Lubricating them is the correct way.

schamran

Remember you just need a film of oil though. They don't need to be coated like a caramel apple. Excess oil collects in the bottom of the hole, and more or less hydrolock a bolt, causing it to break.

85crewcabbie

Thanks to all for the advice and help. I ended up removing the head and installing a new bolt set from Cummins. I called ARP and they only make stud sets for these engines so I ended up at Cummins. I did not reuse the gasket, but I must say It came off nicely without sticking anywhere and certainly looked like It could have been reused. Because it was a composition style gasket (FELPRO) and not a solid shim type, I half expected it to delaminate upon removal but it didn't. I agree with those who expressed concerns about overoiling the bolts before insertion. In both cases I did dip the bolt in oil but wiped nearly all of it off. The most interesting thing to me in all of this is that when I torqued the old head bolts I reused, there was a lot of rotational movement to get them to "click" the wrench for each 10 ft./lb. increment,guessing between 30-45 deg. which caused me to go hmmm then. As some of you mentioned, it had me questioning my torque wrenches calibration. But the new bolts torqued up so easily and consistantly with about 10-20 deg of rotation for each increment. I'm now convinced that, for whatever reason, my old bolts were stressed/weak. A number of the old bolts showed clear signs of abnormal stretch upon removal. If I were to do another head gasket, I'll replace them without hesitation unless I KNOW (not hope,think, or believe) they are not originals. Back on the road with 300mi. so far and all seems well. While I snivel when it's down, I'm sure pleased with it when its running.

Trebor

I don't have my Cummins engine manual close but IIRC the torque spec's are for the engine at room temperature [COLD].

Temperature has a direct effect on stress and stretch properties of aging metal. This effect can be compounded after going through thousands of heating and cooling sessions that occur whenever you normally operate the engine over a long period of time. This is also the reason that the "torque to angle" head bolts on some engines require replacement after they are removed.

Then of course, individual results in different situations can vary...

85crewcabbie

Trebor-I agree with respect to heating cycles and even ambient air temperature effecting metal. That is part of the reason I decided to go with the incremental torque method instead of the turn to torque method. It was hard for me to grasp how a person working in an unheated garage on the east coast in winter could get the same final torque setting as a person working in Phoenix in the middle of summer using the turn to torque method. In my example above the difference in room temperature could be 50-80 deg. I had made disparaging comments to a local, retired diesel mechanic here about how silly I thought the "drop" test was for headbolts for example (especially given that mine passed it and yet seem to have been substandard). But he reminded/informed me that for every one of these engines in one of our trucks there are probably three (or a dozen) more in the middle of the Arabian desert pumping water or in a piece of harvesting equipment on some farm in India. His point being that Cummins has to make a precedure that is doable in whatever far flung corners of the globe their engines are in, and it's a valid point to me. The down side of his argument, at least to me, is that cummins service procedures are the best compromise to allow servicing regardless of location rather than what is ideal or best practices for longevity. Not that I know of course, just food for thought.

KRB

Did you measure the old bolts first?

And whats the "drop test"?

Glad you got her going again.

85crewcabbie

No, I did not measure them (overall length I presume) since I had no data to compare my measurements to. Drop test is something I had never heard of until I started doing research on this website. Simply drop them on concrete and if the bolt "rings" its "good" and if it "thuds" (no metallic ring) it's not (at least my interpretation based on what I read with plenty of room for error on my part based on my interpretation). Drove another 600 mi yesterday and truck performed well. My mileage is up by 1 mpg which was surprising to me. I think it would have been more except I did a lot of mountain driving and then got stuck in the mother of all traffic jams (perhaps a bit of exaggeration but not as much as one might think) leaving Phoenix. Wasn't towing but had approx. 1500lbs load on flatbed.

Trebor

This is the reason I won't touch a Cummins engine without a service manual in hand. Asking for help on specifications on a forum is also good but you need some time invested BEFORE you begin. It can save a lot of cost & aggravation.
Did your new head gasket come with a go & no go head bolt length gauge?

85crewcabbie

I saw nothing inside the Felpro gasket set that could be a go/no go tool. Certainly there were no instructions supplied. While I don't have access to a Cummins manual for the 6B engine series, I do have, and did read, each of the Dodge factory service manuals from 1989 to 1993 inclusive to get some background since this is the first diesel engine I've ever owned and worked on. Not sure of your point? Is it that only cummins manuals shoud be used? I saw nothing in the Dodge FSM's about measuring bolt length though I could have missed it. It was in them that I did see a reference to replacing them every time the head is off. But thanks for the words of caution and wisdom.

patdaly

FWIW, Cummins head gaskets should come with a gauge to check stretch, makes it really easy.

Doubt the FelPro does though.