7m headgasket mileage with high horsepower

[mk3ukr]

Had to look more into this, the v-power is rated minimum of RON 99 and MON 87. I guess in USA you use RON + MON, so the v-power would be the average between RON and MON (87 + 99)/2 = 93. So it would be 93 pump gas.

Are you sure MON of this gas is as low as 87? Even according to our standards here in Ukraine MON should not be lower then RON-8. So, I hope 98 RON I am running here is ~ 94 as per US standards.
14deg at 24psi is too much of advance on pump fuel. Do you inject meth/water?. My timing is 13deg at 19psi, this is with 75/25 MW injected. Head gasket is normal, 1.3mm, CR = 8.23:1

 

[figgie]

well at 24 psi an 87 mon. The fuekl is detonating hence the headgaskets falling of like flies hitting a UV light.

 

[ForcedTorque]

I'm not sure about the RA value what the local machining shop can achieve (they just told me their machinery should be good with mhg).

I guess I'll look for another machining shop and get the surfaces lapped or if there's no way to get the gasket hold I'll just throw in a new one or use sealer spray on the current gasket.

Thanks in advance.

-Toni

If done correctly, it should hold for a good while. In my opinion, your machine shop did not want to turn away the business. The answer to your question should not have been "(it)should be good enough". Find a shop that knows for sure!

Also, I believe it has been said around here that you should not use a sealer spray on a MHG. Someone correct me if I am wrong there.

 

[gtsfirefighter]

Here's the link regarding sealer on MHG.

http://www.supramania.com/forums/showthread.php?t=29335

 

[toniz]

Hi, thanks for all the answers, they've been most helpful to me as I'm quite new to all this stuff

Anyway, we today retorqued the head bolts just to see if they were loose. There's the first mistake made not retorquing the head. Most of the bolts we're loosened 1/8 and then to get the proper torque they had to be retorqued for 1/4 - 1/2. I'll propably give the headgasket a try tomorrow, but I don't believe too much into it as the viton must have escaped when it has leaked

The V-power I have been using seems funny, it's truly rated RON 99, MON 87 and here every fuel is rated by the RON and always I thought it would be best to use the "99+ octane" fuel. One of the standard 98 sold here is specified RON 98, MON 88 (it's also cheaper).

For the ignition I guess I'll reduce the advance a bit and use a different ignition map when running with proper fuel. Also dropping the boost a little bit sounds reasonable.

Today I checked 1st and 6th plugs quickly and as far as I can tell they didn't show any signs of major detonation. I'll get more into it propably tomorrow. Also I'm not using water/methanol injection. I guess that would be a nice thing to add.