Megasquirt Timing and Fuel Map Thread

[turbski]

I get a ton of blowby too. My rings are definitely shot. But I'm still gonna send it till it can't anymore. Got a built 2.9 on the side ready to go once it does, but till then I'm gonna fill the gap with boost lol

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i don't know if i can live with it. i also hate doing thing cheap but funds are limited so when (if) i can get the motor out i am hoping that i can get away with a hone job and new rings to stop the blowby

[turbski]

also forgot to mention that the electronic boost controller was plumbed ass backwards...…. the first 3 pulls we made caused the car to cut fuel due to the 21psi we kept hitting it with. hmmmmm sure that did not help my head gasket hahaha

[SLEEPYDUB]

I get a ton of blowby too. My rings are definitely shot. But I'm still gonna send it till it can't anymore. Got a built 2.9 on the side ready to go once it does, but till then I'm gonna fill the gap with boost lol

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[turbski]

sure do

[turbski]

It was more than likely the culmination of a huge gaskets, older studs, and the fact we threw so much timing at it to attain the power it made on low boost.

I have put a feeler in another section "turbo pcv valve" because i believe my rings are letting go. Im getting more than a little bit of blowby coming from my vented catch can. When the head was off the cylinders showed almost no signs of cross hatch (glazed) im considering pulling the head to hone the cylinders and replace the rings

[SLEEPYDUB]

Do you have a dyno graph of that run?

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[turbski]

That was the million dollar question. I have a couple friends that run insane boost in their diesels and re use them, I think it really depends on what arp gives for stretch limits and installing them correctly. I wont say it was the head studs fault for what happened because i was never able to get to the "root cause". I followed the recommendations from a lot of sources on this forum and my gut and replaced them as a precaution after hearing that the last time they were replaced there were questionable torque findings after a couple heat cycles

[SLEEPYDUB]

How long can ARPs be reused? Curious Bc I've had mine off 4 times now

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[turbski]

.120?!?! No need for that, the m20 has low enough compression, I have put boost on much higher comp ratios without blinking twice. Also, the MLS gaskets hold just fine in spite of surface prep, if anything you will just get a little bit of oil/coolant weeping. I drill the rivets and spray both sides of each layer with copper when the surfaces aren't fresh.

Really surprised you had an MLS fail without damaging pistons - they usually go first. MY preferred method for boost is o-rings and Goetze gasket, that way you still have a "fusable link". Changing a gasket is much easier than pistons.

100% agreed. I believe I got lucky that time, when the head was pulled the rivets were there, no signs of copper spray. I had posted my findings. the failures were evident from cylinders 1,2,3,4, and was only under boost. The tuner figured we were lifting the head at only 8psi.

upon further investigation and talking with the previous owner (local guy, on this forum) the arp studs correlating to cylinders 2,3,4 for some reason would not hold a torque. I was told they had been on since before he got the car and had been on and off at least 4 times in his ownership. that's when I decided to pony up for another set of arps and go back to the oem thickness goetze gasket.

[turbski]

that's not to say im not having different problems with it at this time but that's for a different thread I spose

[ForcedFirebird]

.120?!?! No need for that, the m20 has low enough compression, I have put boost on much higher comp ratios without blinking twice. Also, the MLS gaskets hold just fine in spite of surface prep, if anything you will just get a little bit of oil/coolant weeping. I drill the rivets and spray both sides of each layer with copper when the surfaces aren't fresh.

Really surprised you had an MLS fail without damaging pistons - they usually go first. MY preferred method for boost is o-rings and Goetze gasket, that way you still have a "fusable link". Changing a gasket is much easier than pistons.

[turbski]

The gasket was an mls .120 thick. Previous owner installed but never had the block or head surfaced. Timing is definitely aggressive. My thought is because those surfaces were never prepped, the hg never had a chance. It was replaced with a goetze and brand new arp studs. Has been run pretty hard since with zero hg* issues

[SLEEPYDUB]

Yea that's what I was thinking. I run a lot of timing too but that's much higher then my map and I'm on e85 and a 2.7/885!

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[ForcedFirebird]

Why did the headgasket let go? Timing is pretty aggressive in that area for pump gas so that could be the culprit I assume?

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I would bet on the timing being too aggressive. ~21-22° at 140kpa is pushing the limit on a stock gasket and 93 pump fuel. Even in NA form, the engine doesn't need over 30.

[SLEEPYDUB]

Why did the headgasket let go? Timing is pretty aggressive in that area for pump gas so that could be the culprit I assume?

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