RACESTANG

I got Cobra 324cu.in last year but i always have a problem with the leaking head gasket on driver side

First time i installed with Copper head gaskets and 2nd time i used Cometic head gasket for Darton and it's still leaking!!! I did retoqued the heads too.

I never have a problem with the passenger side.

Last month i send my longblock to VT Engines, the people i bought this shortblock from.

They said the head needed to remachine for 0.015. That's caused the leak head gasket on the driver side.

Is that true? Just for 0.015?

I took a look at the pic from the first time i got my shortblock. I saw the holes between sleeves did not line up on the driver side ,but on the passenger side they're lined up.


At Darton sleeve Manual said


What do you think of the alignment half holes on those sleeves? Can they cause the leaked of my head gasket or could it be something else?



Here is a pic of my shortblock on driver side:






Thank you for any input.


Dan.

MAC4264

If your head really needed .015 to make flat again that was your problem that is a whole bunch. I also prefer to machine the decks of the block after a sleeve install. As little as .002 of the sleeve being to low or high in the block can cause this same problem. You can get .002 off your depths/ lenghts in a hurry when maching. The last LS2 sleeve install we did we were this much off and we surfaced the block to true the deck surface up.

RACESTANG

MAC4264, Thank you for you input.


Also BIG thank you to Steve - Race eng.


I was appreciated.


Dan.

MAFterburner

Just to bring this back to the top, I have the same problem with my engine. It's also a VT324 Darton setup and has a coolant leak on the driver's side. I'm also using the cometic gaskets. How has your engine held up since the head was decked?

MJ

Steve - Race Eng

iTrader: (1)

VT does their own sleeve installations so I don't know for sure what is going on. Was your block brand new or used? Were the heads new castings or used? New castings must be stress relieved or they will not stay flat in service.

If we assume everything was done to spec. (I wrote the installation manual) I would recommend a thin coat of copper spray on the head gaskets. Cometic says dry but I have seen a few motors weep past the head gaskets if no copper or similar sealant is used.

You should be using Evans coolant by the way. I hope that is what you implied by "coolant".

Steve

MAFterburner

Hi Steve,

I really appreciate you taking the time to reply. The block was new and the heads had already been on the car. I'm using Evans NPG+.

This happened to another of my Darton setups (coolant weeped into the cylinders) and by retorquing the head studs after initial heat cycling, the problem went away. This engine has about 5,000 miles on it and I haven't retorqued the head studs yet. What exactly makes this necessary?

As a side note, do you recommend any type of stop leak added to the coolant for minor weeps like this?

Thanks,

MJ

Steve - Race Eng

iTrader: (1)

Good to hear you are using the recommended coolant.

I don't like using stop leak products because they tend to plug up the radiator and heater core, but they can be used with Evans.

The reason you need to retorque is because the engine is aluminum. The original fastener tension relaxes after heat - cold cycling because the aluminum head, block tend to move around a bit. You need to bring fastener tension (torque) back to the design specification or a blown head gasket, leaks can result.

Steve

Slow Z28

iTrader: (19)

Is that what will be listed on the bottle? I had never heard of recommended coolant for sleeved engines till now.

Is that the only recommended coolant? Is there different kinds from different sleeving processes?

Steve - Race Eng

iTrader: (1)

Wet sleeves are subject to cavitation damage on the exterior surface ie vacuum bubbles forming then imploding with great force on the surface causing pitting. Evans coolant is cavitation resistant. You can use Evans type R on the street now that it contains the additive package for corrosion, etc. And yes, Evans is the only recommended coolant for Darton MID sleeves.

Dry sleeved engines can use conventional coolants.

Steve

KHShapiro

iTrader: (10)

Steve, With the use of new heads non stress relieved is it just a matter of retorque?

Steve - Race Eng

iTrader: (1)

Keith,

If the castings are new, they really should be stress relieved. Not only will the heads stay flatter, the valve seats will stay round as well. Flatness and valve seat run out should be checked after stress relief and corrected as necessary.

Steve

MAFterburner

Thanks again. What procedure do you recommend for the retorque?

1. Loosen each nut individually and retorque (following recommended order)

or

2. Loosen all nuts initially and fully retorque following the original installation.

Thanks,

MJ

P.S. Do you build modular motors? If I can't get this leak under control I may want to send my longblock to you for inspection/repair.

KHShapiro

iTrader: (10)

Thanks Steve, as always you make me ask questions i never pondered. I was able to discover that ETP's heads are Stress relieved during the forging process and .300 thicker than stock.
My Steve-Radar is on so whenever you post up about anything i am soooo there to make sure i dont miss anything. Thanks again Steve.

Steve - Race Eng

iTrader: (1)

I recommend your procedure #1 below.

I don't have time to build motors any more with all the blocks I do. I have a friend in Chula Vista I can have you send the block to. That way I can inspect the block and see if there is a problem with it.

Steve

MAFterburner

Hi Steve,

Here's what has transpired since I posted in this thread. I sent my first oil analysis to Blackstone after 1500mi on the engine. All was well. The wear metals were a little high as to be expected from a motor of that low miles. At that time I switched over to Amsoil 0W30 and at 5000mi (3500mi on oil) I drained it and sent it off again. This time it came back with 0.94% antifreeze and even higher wear metals (iron, lead, copper). About 3wks before I sent it off I started slowly loosing coolant. At that time I threw a can of liquid aluminum in and the cooling loss seemed to stop.

I received this analysis report on Monday. Shortly after I came home from work, put a cooling system pressure tester on the reservoir, pumped up to 16psi and after 5 minutes (with warm engine) the pressure dropped to 15psi. I let the car cool over night and did the test again. This time there was no drop in pressure from 16psi in a 5 minute period.

At this point in time, I followed procedure #1 from my post above and retorqued the head studs using a generous amount of moly lube. I could tell that the torques on the studs were not uniform (used a snapon digital torque wrench which shows breakaway torque). After the job was all complete I pressurized the cooling system to 20psi and after 5 minutes there was zero drop in pressure (with a warm engine). I let the car cool again and repeated the test with the same results.

In summary, it looks like the retorque did the trick. I've got 300 miles on the new oil and when it hits 1500mi I'm going to send it in again. I'll post here the results.

Thanks for your advice! It is much appreciated.

Best,

MJ

howard wolf

I have a 6 page list of FAQ's for a Darton wetsleeve installation if anyone is interested. Send me an email and I'll forward them to you.
lcwolf03@comcast.net

MAFterburner

Quick update: 1200 miles on oil since retorque. No coolant loss, oil appears cleaner looking than the last drain.

MJ

KHShapiro

iTrader: (10)

thanks for the update MAFterburner!

Uthinkso

I can back that up as well. Cometic does day dry but after a few weapers, I use Copper Coat on every MID block I do.

racer7088

I have used Steve at RED exclusively and we have had no real problems like this so I think a lot is due to the sleeving or the block moving later. We have had these blocks in mulitiple 9 second applications and they make very good power with out problems. I think we had one of the wet sleeve deals leak a tiny bit initially but it disappeared after running the first day and one retorque.

Steve has been doing these the longest so he's already scienced it all out and it helps that he is also one of the principals in the sleeves design etc. You probably will have to take a tiny bit off both decks to true it all back up if you think it has moved but you need to measure the deck flatness as well before doing that since that means you're pulling the motor and it may not even be your problem possibly.