#138760, "Boosted 420A head lifting? Any tips to keep head planted ? "
Question to those with boosted 420a
Running a fairly built engine now for several years. I've lifted the head once before but blamed it on detonation when a fuel pump was slowly failing.
I'm back to the same issue now. I used a cometic MLS gasket and arp studs. I'm at about 18-20psi on around 14deg timing (93pump) and I'm pretty sure I'm lifting the head again. I get small amounts of compression in the cooling system. Turn the power down to 15ish psi and no more combustion pressure.
I've seen some old forum guys running close to 24ish psi before having to go to 1/2in head studs. Any other tricks to keep the head planted? I'd rather not take the block out to take to the machine shop.
I'll try to upload some pics if I can remember how lol
#138761, "RE: Boosted 420A head lifting? Any tips to keep head planted ? " In response to Reply # 0
How high are you torquing the studs? It's been a long time, but I always went up to at least 90ft/lbs and never had too much trouble with either the 2.0 or the 2.4.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#138763, "RE: Boosted 420A head lifting? Any tips to keep head planted ? " In response to Reply # 2
You can always pull the valve cover and throw another 15 to 20ft/lbs of torque on them. Just be careful with the corner studs, they are not as robust as the others.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#138764, "RE: Boosted 420A head lifting? Any tips to keep head planted ? " In response to Reply # 0
Update, finally got around to pulling the motor out and disassembly. Was able to find my head gasket leak is actually the head, due to detention pitting in the combustion chamber severe enough to erode the aluminum under the fire ring.
all 4 pistons are melted on the intake side with stuck rings and one cyl wall scored beyond repair. I would post photos but I seem to have forgotten how on this forum.
not sure why it was detonating. I was only running about 13* timing at the top around 18-20psi. Had tuned for a middle 11.5ish AFR under power and running Pump 93 exclusively. I do not have access to E85 where I live and racegas was not an option for me. I never heard or noticed and signs of detonation.
My only guess at this point is that the base timing in the megasquirt was off somehow or that I had too much timing in my cruse / part throttle area.
Anyhow, on that depressing bombshell I've unfortunately had enough with this engine and transmission combo and have started to gather parts for a LS and Solid axle swap. Tube chassis floor and trans tunnel. Mustang K member, etc.
Still debating on staying manual or trying an 8hp70 conversion...
When the build starts ill try to document some in the pits section.
until then ill have some hard to come by parts for sale soon.
Ride it hard and put it away wet.
I fix it to abuse it, and abuse it till i find the next weakest link.... my wallet
