This is a longer video that shows my whole 2nd session. First time at this track, first two sessions total washouts, with no instructor. Just me trying to find my way around and dodge P-cars...



Total blast...

Lance,

I'm not sure about the system you are using, but the HP and Dominator systems are generally always logging when the vehicle is running. At least I have mine set up to do that, I think that was the default (been a long time since I had to make that choice).

Might be worth a look in the Holley program (you can use their tuning software and not just the handheld, correct?) to see if any logs are available.

Good luck!

Thanks. I have it set to only log when manually started and stopped.

I watched the other video in the wet again and the screen was easier to see then. It is probably spiking rich when it flashed yellow, not lean...that has kinda been its MO since we started tuning it.

We'll figure it out, fix it and move on. Part of the deal...

More progress made today.

Figured out a way to pull the engine with car on the lift.

https://photos.smugmug.com/1985-Mont..._112131-XL.jpg

All kinds of room

https://photos.smugmug.com/1985-Mont..._112223-XL.jpg

Here is passenger side head. All looks good, just a bit more oil on #4 exhaust valve.

https://photos.smugmug.com/1985-Mont..._130758-XL.jpg

Tops of all of the pistons look normalish as do the cylinder walls.

https://photos.smugmug.com/1985-Mont..._130738-XL.jpg

This is #4, the one in question.

https://photos.smugmug.com/1985-Mont..._130001-XL.jpg

Popped #4 out and found this.

https://photos.smugmug.com/1985-Mont..._141127-XL.jpg

https://photos.smugmug.com/1985-Mont..._141136-XL.jpg

https://photos.smugmug.com/1985-Mont..._135047-XL.jpg

Multiple rings are broken in multiple spots and the top edge of the piston has started melting away. Hard to tell what happened first, oil ring could have failed, let oil in chamber which may have raised compression just enough to cause detonation raising temps above what piston could handle. One or multiple rings could have been just a bit tight, got a bit too hot and broke causing loss of compression. Or something with cooling system could have caused an air pocket, causing that cylinder to get just a bit hot and start the meltdown. It'll be interesting to see if any rings are broken in any other cylinders, haven't pulled any other pistons out yet.

Everything else looks excellent though. Bottom of pan was clean, cylinder walls are unscathed, head gasket looked good, basically you wouldn't know there was problem if not for that one piston. So glad I stopped when I did, that piston was one straight away from exploding.

Bearings look pretty good still.

https://photos.smugmug.com/1985-Mont..._135237-XL.jpg

I won't, but I literally could put a new piston with new rings on that rod and bolt it all back together again and I'm sure it would be fine.

More than likely unless it's stupid expensive it'll get new forged rods and pistons and a refresh on the bearings and rings and a good clean up. I may even consider a cam change to bring things more in line with the rest of the build. We'll see.

No hurry to put it back together though, it needs a new clutch disc and I may put a new accessory drive setup on the front as well as the engine refresh so this will be a bit of an extended project. Pretty dang happy I still have so many good parts left though, could have been much worse.

Sorry to see this happen, Lance. LS swap time or sticking with the stroker?

Why would I LS swap at this point? :D

That would just be silly...

True, but more power at this point will require an LS swap or a silly expensive SBC build requiring boost or high compression and race gas.

I'm considering it if I keep the car. I'm kind of addicted to boost after having the BMW. Not that I'm wanting more power. I'm wanting a smoother idle and easier to drive car. The sound our motors make can't be beat though. That, I would miss.

Good luck what ever you decide, Lance.

I really don't want or need more power than we were making with this combo. It was pretty perfect for what I do, pulled out of the slower corners awesome while would still run with 500 hp to the rear tires LS stroker cars on the straights all while idling smooth at 680 RPM with 18" of vacuum for the brakes. These heads made the VE tables look similar to LS top ends, no need to upset that apple cart at this point.

Any changes I make will strictly be toward making it safer to live longer first and maybe a cam to flatten out the curves a bit.

I suppose Optimists would say #4 didn't grenade & impact everything else so it's 'all-good' :D.
Disclaimer: I'm a Realist... I guess it is part of the deal but still sucks it happened.

What changes are you considering for the cam? I really liked the combo & still have the info/specs jotted down in a note-book for reference. One thing I never asked though, was it ground on a reduced base circle? A buddy who I was bench racing & talking SBC/FI retrofits with asked when I spoke about your set-up.

Spent a week or so investigating, diagnosing and soul searching. One thing I found changed the direction I thought i was heading more than anything else.

When I pulled the rest of the pistons out yesterday, I found this broken ring land in #8.

https://photos.smugmug.com/photos/i-...Tb3d6ZG-XL.jpg

Everything else about that cylinder was normal as could be.

This tells me that the top end we put together simply outpowered the bottom end and the weakest link (cast pistons) is what gave up first.

Since the block is a 4.005" bore, there is no forged off the shelf piston that will work with it, so machine work it is. This actually helps though because now I can do the machine work to match the parts I pick out...instead of the other way around.

I'm still very happy with the power this combo made so I'll not be making any drastic changes to the recipe, just fortifying some of the weaker parts inside and putting it all back together once again. It'll just take a bit longer and cost a bit more is all.