15 replies to this topic

[VIN18M]

So after my last dyno run I noticed some coolant leaking down the timing side of my engine. I assumed it was a water pump seal going and flicking coolant around - after further inspection I realized this was not the case.
So now after giving the car a good hiding, I get a decent coolant leak down the back of the block and on the timing side, and coolant wheeping on the intake side of the head gasket area. The car isn't running hot or using water or oil and made plenty of power on the dyno, so I don't think I have a leak between the cylinders, but its shitting me so the heads coming off.
I'm currently (3+ years) running ARP head studs and a 1.5mm MLS head gasket with 25psi of boost. But have been hearing/reading a lot about issues with getting the MLS to seal so was considering going back to a standard fibre gasket.
There aren't many options around for the 93t and I want to stay away from cheap garbage. Also considering going a thinner gasket to bump up the compression slightly, I have valve clearance for a thinner gasket.
Can anyone offer any insights/opinions/experiences in this?

[leadfoot]

i ran a composite on arp studs (std style) and pushed through from a cylinder into the water jacket on 20psi currently on an ebay spec MLS and compression is better than ever at 230psi across all 4

[VIN18M]

Yeah I have a feeling I'm running the same gasket you are. I'm a bit nervous going away from the MLS. I don't think I had issues with it sealing to begin with, but have a feeling the head may have lifted after the last dyno run.

[jack be nimble]

Neil had same issue, with his jumbuck. It was pushing water between the layers of steel. I think he want back to fibre. But he doesn't run as much boost

Edited by jack be nimble, 06 August 2017 - 10:26 AM.

[VIN18M]

Yeah sounds like what might be happening to me Jack. I was warned if we put any more boost through the motor it'd start to push water, just so happens the last dyno run it started doing that exact thing.
Wonder if it's worth tightening the studs up another 5ft lbs this time around.

[bj]

I'm running standard mls with arp and only started having issues at 35psi but that might have been due to running out of pump...

the studs where torqued up to the recommended specs, 84nm of i remember correctly but now pushed it to 100nm. they are only 10mm so not sure how much more they can take.

ps. sohc

Edited by bj, 06 August 2017 - 12:57 PM.

[leadfoot]

I'm running standard mls with arp and only started having issues at 35psi but that might have been due to running out of pump...

the studs where torqued up to the recommended specs, 84nm of i remember correctly but now pushed it to 100nm. they are only 10mm so not sure how much more they can take.

ps. sohc

if your running their std (black) studs for the 3sgte then the torque spec is a measly 60ft/lb (this is what i had originally) i have since gone to the higher spec and much more expensive custom AGE studs which recommend torque to 80ft/lb this is a huge difference in clamping on the head.

on mine i think the issue was detonation and the head lifting a little as the exhaust studs were notably looser on disassembly

[VIN18M]

Kyle it sounds like I've had the same issue. I had detonation problems again after getting the car retuned so swapped the fuel pump out and now running back to normal again. I'm starting to think based on the above that I may have lifted the head when it was running lean, and that's caused the issue.

 

I also looked back on the torque specs for the 3sgte studs and yeah they are only 60ftlbs. I think I did mine up to 65ftlbs originally because I thought it was too low. I've since tried nipping them up to 65 again, but they are still tight and the leak is still there.

 

As long as I don't have detonation issues again, I think the ARPs will be fine, but I'll be torquing them up tighter this time around.

[bj]

so to sum up it's really a detonation issue not the head studs.

mine is just about ready for more punishment so i guess we'll see how much they can take.

[VIN18M]

I wouldn't have thought the amount it was driven and how hard it was driven when lean would have caused this issue, but yeah looks like that might have been the cause.

 

I guess I'll find out when the head comes off for sure.

[bj]

well mine didn't look damaged in any way when i pulled it apart...
or at least it was to difficult to distinguish any damage that wasn't from simply disassembling the engine.

[bj]

I wouldn't have thought the amount it was driven and how hard it was driven when lean would have caused this issue, but yeah looks like that might have been the cause.

 

I guess I'll find out when the head comes off for sure.

sorry maybe you've covered this in another thread... any update here?

[VIN18M]

Been driving the car about once every month (normal as it's a weekender). Seems to be fine except for a coolant leak on the timing cover side, which gets worse depending on how hard I push the car. I have a feeling I'm pushing water because of a leak around the water jacket - don't think there is any issues between the cylinders because it doesn't miss, splutter or have any water coming out the exhaust. .

 

I've purchased a new thinner MLS head gasket to up the comp a little more and get some more response from the setup. I also have a new set of ARP studs, just looking for the time and motivation to pull the head off and get them in.

 

I think all of the above is due to the fuel pump failure I had, nothing major but an excuse to mix up the setup and do something different  guess.

[bj]

i think next time I'll just run a m11 tap through the block and use the evo ARP studs.

Still the ARP M10 mr2 ones are holding up to consistent 35psi and has seen as high as 43psi.

[VIN18M]

Mate, if they are holding up for you at that boost level, I wouldn't bother upgrading them, that's insane! Surely if you need to run more boost than that, it's time to upgrade turbo's?

 

Anyone know if you can get a head skimmed with valves, guides, retainers and springs still fitted?

[bj]

Mate, if they are holding up for you at that boost level, I wouldn't bother upgrading them, that's insane! Surely if you need to run more boost than that, it's time to upgrade turbo's?

Anyone know if you can get a head skimmed with valves, guides, retainers and springs still fitted?

upgrade... nah haven't got anywhere near the limit of this thing.

Edited by bj, 10 October 2018 - 08:45 AM.