Head Gasket Leaking

[Epic904]

Just had my motor rebuilt and put on a brand new mitsubisshi 4 layer head gasket, and i was filling the motor up with oil and noticed the back of the block was leaking. i felt the bottom of the head gasket and noticed it was coming out from there, put under pressure it doesn't squirt, should i just retorque the head

 

[Spoolin98]

What did you torque it to in the first place and how did you torque it? Did you follow the right sequence?

 

[DirtyBirdRacing]

You have to make sure to torque it in sequence as was said before, but you also have to make sure to torque it in steps so that you do not warp the head.

Bill

 

[Epic904]

well the motor was assembled by a professional, and this is happening so i loosened and torqued one bolt at a time in sequence and it still leaks, this was at 85 ft/lbs i'll try it agian with more moly lube at i think arp said 90 of the top of my head tomorrow, just odd that it leaks when there was no oil pressure and that i leaks the same with oil pressure, not running thou, just being primed

 

[Epic904]

and the sequence is going criss cross from the inner to the outer


1(7) 2(5) 3(1) 4(3) 5(9)
6(10) 7(4) 8(2) 9(6) 10(8)

 

[GVR4592]

The head and block surface probably weren't machined correctly.

 

[Maglin]

Ouch. Well to the "their is no pressure their" statement that is partially false. Their is crank case pressure and the oil running down the galleys get pushed out of the head gasket. I always use some Gasket Sealant (Mopar) on all metal HGs for that reason right their. Never had issues since doing that. And pretty much all the auto makers are using MLS HG's now in all the production cars.

But since you had this done by a professional take it back to him. They should fix it for you.

 

[Epic904]

well by no pressure, i meant oil pressure, when i crank it over with the mpi fuse out it doesn't leak any more than it did when i was fill the engine up with oil. I will try to retorque the head to 100 ft/lbs and if not well then it will have to get towed to the shop since i i installed the motor and trans myself and really don't feel like taking everything off agian for something that i didn't mess up on for once

 

[Epic904]

ow and there was sealant on the headgasket, it was red so i assume it was to seal the headgasket, i was told i had to retorque the head after running it, but i never seen a head gasket leak on a motor that just had machine work done to it, and even on the motors i had rebuilt and didn't cut the heads on never had that happen.

 

[Epic904]

just to let everyone know, i retorqued the head with some moly lube on the arp bolts in sequence and in steps of tight, then 60, 80 ,95, 110 ftlbs. and yes i know arp says 90 ft/lbs but there it was leaking so just went a little tighter

 

[Maglin]

The thing about not going over their amount of torque is due to the yield of the metal. You end up stretching the studs. They stretch some but over torqueing them will cause them to overstretch and they will be damaged and actually start to pull apart. A lot of people have torqued their ARPs to 110-120 but it really isn't needed. Usually a lot of sealing issues is from one of two things. Imperfect sealing surfaces or derbies on the sealing surfaces.

 

[dsm-onster]

Are you talking about torquing to 110 w/ lube or oil? 6bolt or 7 bolt studs. The different diameters will drastically affect stretching threshold. . .

I don't think arps will stretch in any amount to mention being over torqued w/ in reason. If arps can survive not stretching when detonating at 500whp, then I don't think tightening them to 110 ft-lbs will stretch them. . . I torque mine to 120 ft-lbs w/ 30 weight oil and havn't had any troubles.

 

[Maglin]

Are you talking about torquing to 110 w/ lube or oil? 6bolt or 7 bolt studs. The different diameters will drastically affect stretching threshold. . .

I don't think arps will stretch in any amount to mention being over torqued w/ in reason. If arps can survive not stretching when detonating at 500whp, then I don't think tightening them to 110 ft-lbs will stretch them. . . I torque mine to 120 ft-lbs w/ 30 weight oil and havn't had any troubles.

Their is a reason why they give you the torque for their head studs and all fasteners they make with moly lube and with oil if I recall correctly. I know the 6 bolt studs is 80 lbs. And if you don't measure them before you install them and write the data down and then measure them again when you tear it down the next time. Then compare the measurements for each individual stud. If you over torque them you run the risk of them stretching. I don't know the spec when ARP recommends you replace them but it's on the paper work that they come with. The reason being that they have gone past their yield point and are not up to the rating of the original stud. Will they break? Probably not. Could they break? YES. I know I've taken bolts past their yield points in the past. Was just fine until the next time I removed and reinstalled them. Every single one broke and it costed me almost 1.5 hours worth of work to remove the broken bolts that happened to be flush with the mating surface.

Proper installation is vital. Proper torque sequence is also very vital. Torque in small steps. Those very cautious can go in 10-20 lbs increments. Those of us doing this for a living usually just follow the manufactures recomendations.

 

[dsm-onster]

Proper installation is vital. Proper torque sequence is also very vital. Torque in small steps. Those very cautious can go in 10-20 lbs increments. Those of us doing this for a living usually just follow the manufactures recomendations.

Amen! per what I got from ARP the 6-bolt head studs should be torqued to 110 ft-lbs w/ 30w oil. I go over about 9%. I torque with the recommended sequence the go one more time to the 120 ft-lbs.

 

[groundPork]

I think it's safe to say you've done what you can. I really would take it back and have the engine builder check it out. It should not be leaking period. I agree with everyone else here, torque specs, and sequence are there for a very good reason. You're obviously not fixing the problem, but there is a slight chance you could make seomthing worse. Besides, you paid real good money for a pro to put it togather, have him give you your money's worth.

 

[jpolizo]

This is purely anecdotal, but a friend of mine was in Taiwan visiting his girlfriend's family. Some other relative of hers worked in a Mitsubishi dealership and my buddy went for a visit since he and I were rebuilding my 2G. The mechanics there all told him that they had given up on the MLS gaskets in the 4G63 because they had too many problems with them leaking. They showed him some kind of sealant that they had mixed up themselves to try and fix the problem but they said that even that was not reliable. They were using only fiber gaskets.

As for me, I used a cometic on my rebuild and it leaked as well. I tore it down again, put in an OEM fiber gasket and the thing was perfect.

 

[GVR4592]

This is purely anecdotal, but a friend of mine was in Taiwan visiting his girlfriend's family. Some other relative of hers worked in a Mitsubishi dealership and my buddy went for a visit since he and I were rebuilding my 2G. The mechanics there all told him that they had given up on the MLS gaskets in the 4G63 because they had too many problems with them leaking. They showed him some kind of sealant that they had mixed up themselves to try and fix the problem but they said that even that was not reliable. They were using only fiber gaskets.

As for me, I used a cometic on my rebuild and it leaked as well. I tore it down again, put in an OEM fiber gasket and the thing was perfect.

What was the RA on the block and head?