It dun broked......
 

Attachment 1058

Luckily the short block looks great.

JB Weld and done. Easy fix!

Sorry you had to tear into but I'd feel pretty good knowing the bottom end is sound. Good luck getting it back up and rocking again.

Any thoughts on the cause?

Problem I've been chasing for years.

On the first build it was my DD so I use my old set of heads that were on my stock engine I blew up on the track, they were Windsor PI heads with 4 threads in the spark plug hole with around 100 plug changes and 80,000 miles. I had them ported, put some good be-hive springs valves and retainers in them and stuck them on.
Eventually over time one by one I stripped or shot the threads out of the plug boss and had to put some inserts in. Inserts reduce the thickness of the boss and even if there aluminum inserts (which I had) as the plug gets hot from racing or making high speed runs (what I was doing when this happened) the heat eventually melted it, once it melted and exposed the threads of the spark plug it was like a torch cutting away at the boss and the valve and eventually messed up the seat and blew out the valve seal letting oil into the CC. (what made me pull it was smoke)

You going PI again? Or TF heads that solve this issue?

I wouldn't put a set of trick-flow 2v on my lawnmower. Romeo's solve it good enough for me.

Got Romeo's on mine. But you guys seem to like to play with marginal fuel octane. that scares me. I octane way up after my last failure lifting a head.


Jim

We keep the timing down and run them rich for that, we also shift them early to keep the rpm's down.

Mine wasn't octane related, the rest of the cyl's were clean and the timing marks on the plugs looked good too.

When were running them on pump gas, were running an 11.0 AF and 6* of timing max at the end of the run. Thats why they don't MPH, they just 60' the ramp is reversed till 3400rpm, out the hole were running 14-16 to 3400 then 6* every gear after.

Thanks, I dropped a spare set of heads I had off to CNC last week because I pretty much knew it was the heads after all the problem's Ive had with them. I have 4 extra's here now I'm down to 2 lol.

I'd have it back in the truck running again by now already if I would have had them done a year ago when I got them for that reason, but they kept running so I left them there.

Isnt this a new motor?

I'd blame it on the tuner. :hysterical:

Is that considered a lot of timing at peak torque? I see the timing at the higher rpms is low but a peak that seems high. On my evo, I had only a couple degrees at peak torque and about 11 at 7k rpms on 93. Of course my ride was a little 4 banger, but I'm just curious and trying to learn.

Was built back in 08-09, has about 40 nitrous bottles through it and about 50-60 track passes and multiple 300 mile trips to florida with a boat in tow, so no......


Funny thing is, the ring gaps are +.02 larger than what I set them when I put it together the first time, but still well within what most would call wore out. and the bearings look new and still have the coating on them.

I'll probably freshen it up and sell it to go aluminum, or just cross hatch it re-ring, put another set of bearings in it and it put it back in. There's nothing wrong with it, but when rings are only 70$ and bearings are even less, I might aswell.

Please dont reuse that motor. I want to see you go fast.

No, a race setup is 19-20* even at 6400 with good fuel.

On ours, you can push more tq if you come out with more timing, thats why we cut 1.4-1.5 60's in a 4800lb truck on pump gas, considering we stall to around 2k we only see high timing for the first 60 feet at low RPM's.

Its the same short block as yours....... I would like a lighter one though.. we'll see.

Thats what Im getting at.

Him and the builder, and the mechanic that put the insert in...... I believe that one was about 1/16 deeper then the others causing the plug to be lower and expose sharp edges in the CC.

Heads are where it is at..