darkbluez28

370 forged bottom end stock 317heads. just a little over 10:1 compression ratio. borg warner 76mm compressor 75 turbine exducer. holley dominator and bosch 160lb/hr injectors. 93 pump gas. 15 to 17ish psi through the pull. made two passes at the track 1/8 mile on second pass it blew the head gasket on #7 cylinder. after pulling the head we noticed that it has broke a peice of aluminum off around the spark plug and also on #3 cylinder. plugs are br7ef nkg also just so you know the injector sat with e85 in them from the last setup for a couple months and one of them didn't even want to open at all. and we had to spray stuff in it and tap it to get it working again. realy took a risk running them without having them checked. that injector was on #7 cylinder the motor was driven to the track and ran two passes that's all no other time on the motor. timing was 11 to 11.5 at 17 psi and 13 at 15 psi wideband was showing 11.4 still in closed loop using holley. single wideband for all 8 cylinders.

questions.
1. what causes the aluminum around the plug to come off like that never seen it before. Im assuming injectors must be all over the place and those cylinder were leaner. that melted the aluminum
2. timing was conservative IMO but would like to hear what others have to say.

I could not figure out how to attach the holley tune and log or I would post it. if someone wants to tell me how I will. thank you.

rotary1307cc

iTrader: (5)

Detonation plain and simple in that hole. You can even see the melted aluminum spatter

The hg was leaking on 3 there as well

What caused it? Could be many things

The BallSS

iTrader: (9)

Unless you fully trust the person you're getting the injectors from anytime the seller tells you they had E85 in them get them cleaned.
I paid top dollar from a guy who I thought I could trust who said they were fine and after install the car wouldn't idle leaner than 11.9 and be at 10.3 WOT.
I dicked around with the AFR gauge and a few other small items and eventually bit the bullet and pulled them to have them checked.
Two were stuck open and the rest flowed like ****, after a sonic cleaning and some seals they were good as new but now I'm $500+ into a set of $400 injectors.
Lessons learned.

darkbluez28

Well we are going to have the injected cleaned. We are actualy thinking of buying our own injector cleaning setup.
Any tips on the timing and boost is appreciated. We usualy run e85. But do run pump gas in the car. Gonna get a meth kit also realy didn't like seeing 17 psi without meth on pump gas.

tblentrprz

What IAT? Need to read all the plugs after 17psi and pump gas pull to better understand whats going on. Also, how much timing adjustment around peak tq?

darkbluez28

It's a flat 11 degrees at 17 psi and flat 13ish degrees at 15. This was second pull the iat were showing just over 130 f about the time the gasket went. i was planning on adding more up top passed peak torque. Maybe a degree or two after seeing how the logs looked and after checking iat's and etc. and I know I need to start reading plugs. And learn to read plugs well. Are you thinking that was to much in peak torque area. P.s this same motor was in the car for two weeks before and had lost oil pressure. It was ran on pump gas around town and e85 at the track And when it was in it then i had the timing about 2 to 3 degrees more aggressive in the pump gas tune Andi dropped it down to be safe during break in. And when i say two weeks before it was full throttle probably the whole time it was driven. It doesn't get driven easy and it was on the same boost. It didn't even make it through two passes this time. When we pulled motor due to oil pressure, we had just been running e85 and didn't think to flush the system. And when we started it back up this time we had a solid missfire caused by an injector that wouldn't even open at all. But we got it working again. And figured it probably be okay now. That was number 5 cylinder. The one that didnt blow a gasket or anything crazy to the plug. Also I was told that when in the burnout box on the run that blew the gasket the exhaust was making everyones eyes burn. And it was noticeable. So I'm sure it was very lean on some cylinders even though the wideband was showing okay.