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1G Lifting head?? Maybe... I need some diagnosis & help

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
Hi Guys

Im in the process of trying to diagnose whether I am lifting the head, or having head sealing issues on my race motor. So in short, here are some main specs
~ 100mm crank
~ 8.5:1 JE pistons
~ Mitsubishi OEM MLS gasket
~ ARP 12mm head studs
~ Galant VR4 block (same as 1G I think)
~ Evo head (same as 2G I think)
~ Borg S200SXE turbo (makes 16psi by 3000rpm in 5th gear!) Running up to 23psi
~ Kelford TX278 Cams
~ 1.1 Bar pressure cap on coolant reservoir

I think that should be enough of the main specs. I'm logging coolant pressure on the Link, using a honeywell pressure transducer. It does have a pressurized expansion tank rather than the factory recovery bottle style. When I have been hitting boost I see a rise in coolant pressure, more pronounced when the engine has been driven hard for more than half a lap, up to 150kpa, which then settles back down to 100kpa as you sustain load, and when you drop off the throttle it goes back down to 80kpa. There is evidence of mainly air getting pushed out the pressure relief of the radiator cap. This happens at all boost levels but the pressure rise in the cooling system was more pronounced at higher boost.

I have just re-torqued the head studs, put them back to the spec 90ft.lbs and some moved a little more, some went back to original position, the ones that moved more were predominantly on the exhaust side. Then I retorqued them again, up to 95 this time, so 5 over the ARP spec. I havnt had a chance to test it in anger (Cant drive it on the road) but on the hoist against the brakes I was able to get it up on boost and the first couple runs the pressure spiked reasonably high, but I wonder if this was due to having topped up the expansion tank to be brimmed. Then the last couple runs the pressure was much more stable at 100kpa throughout the run.

So really, I'm not sure if I have a pinhole leak somewhere or a head lift issue. There are absolutely no other symptoms of head gasket failure, temps are fantastic. Coolant temps are consistent and low 90's. Its not pushing water but that could be part of the design where there is a head of air on top of the water. On the old system where it ran the recovery bottle it would drop about 50mm from the top level in the system constantly, then stabilize at that level.

Attached files: coolant pressure dsm 1 = pulling onto the main straight at Manfeild
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coolant pressure dsm 2 = on the hoist, loading it up as best as I can in 4th gear, after retorque studs
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Looking if anyone can share experiences on this topic. where limits were found... solutions etc. Thanks
 

1990TSIAWDTALON

Moderator
7,970
3,888
Nov 14, 2013
Independence, Kansas
I wouldn't think 23 lbs of boost would lift a head, well it doesn't on my HX40 motor anyway and that is what boost level I am running. Did you have the block and head both decked before assembly?
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
I wouldn't think 23 lbs of boost would lift a head, well it doesn't on my HX40 motor anyway and that is what boost level I am running. Did you have the block and head both decked before assembly?


Neither would have I. In a previous life this block was running around 40psi on a big garret, but the owner at that stage used a o-ring style head gasket. I do want to avoid that if possible so I don't have to skim the head every time it comes off.

The head was skimmed several years before I got it, there were a couple marks on it but nothing that would catch a fingernail. Block had been done in the past so I just cleaned up the surface. Its definitely something I regret not decking both surfaces again but the build was a lot different when I put that motor together and budget was tighter. It would be nice to rule that out but I know that its entirely a possibility.
 

1990TSIAWDTALON

Moderator
7,970
3,888
Nov 14, 2013
Independence, Kansas
Yes, at least you are aware of that. I understand the budget in different stages of life. My engines all get decked and heads surfaced now. Just something I do to make SURE it is going to seal. I use Cometic MLS and HKS headgaskets on most builds, although I do have a newly rebuilt "stockish" motor that has a FelPro composite on it. On all, I hold the head down tight. More than specified by a book or manual but I don't recommend it unless you have confidence in your abilities to do it.
 

SasaniFab

Proven Member
2,468
781
Dec 1, 2013
Mexico, Connecticut
All of the motors I’ve built use L19s with an hks head gasket. I had a similar issue on a motor when using an oem mls headgasket without freshly decking the block. The hks gasket is just a much better gasket imo , I’d recommend switching to an hks and increases the torque to 105-110, if you can afford it go to the l19s for good measure. When I say freshly decked I mean Within a few thousand miles for the record.
 

pauleyman

DSM Wiseman
6,631
1,773
Nov 19, 2011
oklahoma city, Oklahoma
Have you considered the thought that coolant can pressurize from other sources? Is the turbo water cooled? Do you have coolant going through the throttle body?
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
All of the motors I’ve built use L19s with an hks head gasket. I had a similar issue on a motor when using an oem mls headgasket without freshly decking the block. The hks gasket is just a much better gasket imo , I’d recommend switching to an hks and increases the torque to 105-110, if you can afford it go to the l19s for good measure. When I say freshly decked I mean Within a few thousand miles for the record.

Interesting. Its so hard to know what head gasket is best but I am open to finding another good one. Permanent is a common and easy brand to source here in NZ, i will try to find out about if they are any good also
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
I see HKS advertise theirs as being a stopper style gasket, is OEM one like this too, or does it have a different construction?

The turbo is only oil cooled, throttle body doesnt have water lines.
 

SasaniFab

Proven Member
2,468
781
Dec 1, 2013
Mexico, Connecticut
I see HKS advertise theirs as being a stopper style gasket, is OEM one like this too, or does it have a different construction?

The turbo is only oil cooled, throttle body doesnt have water lines.
The hks head gasket has more layers and each layer is thicker.... It’s really the best you can do for this style
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
Ok, good things to consider. Im going to go warm up the car and get it on boost to see if I have any leakage measured. Hopefully nothing like the final runs last time. If I do have leakage then I think Im going to go down the new head gasket route.
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
Ive just finished doing a couple of runs just against the brakes on the hoist. Promising results:
~ first three runs, basically I started once the water temp was up to thermostat temp, the engine hadn't fully heat soaked yet at that stage though. The first run was zero change in coolant pressure, sat at 100kpa (I've just put a 1.3 bar cap on), second run saw a rise to about 160kpa, but it wasn't in line with boost, happened very late in the piece, 3rd run was similar.

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~ last couple runs were rock solid and only slight and gentle increases which I put down to the rising coolant temperature.

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So at the moment I think I am going to be best to leave the gasket as-is, go out racing and collect data under race conditions and go from there. Im tossing between the Permaseal MLS-R gasket and the HKS one, both use folded stopper rings, and same 4 layers of steel, a friend has been using a Permaseal one in his Evo which is around 600whp with no issues, but plenty of time to research as its a while before Ill be able to get race data

I will keep the thread updated as it develops.
 

Cameron Morison

Probationary Member
28
21
Nov 12, 2018
Christchurch, New_Zealand
Update to the thread. Had a 1/4 mile sprint today. Not at a strip, just on a closed road with the local car club. I was running 265kpa, so 1.65 bar boost and temp was about 15 celsius. It seems the head gasket issues are gone, the coolant pressures remained normal and followed a curve which related far more closely to coolant temperature than anything else, so thats excellent news. Means I can run the engine at the higher boost levels without having to be concerned about the head.

I got the PB down to 10.34 which is pretty decent. Hoping to get a 9 one day which will need better road surface (it was rough chip) or better tyres designed for doing drags rather than corners.

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