Ahsai

BTW, one thing I found interesting is the scavenger pump inlet and outlet ports just mate metal to metal to the engine case/cam cover and there are no seals in between. I think that's because there's not much pressure involved anyway. The pump is more for just moving the un-pressured oil from the cam cover back to the sump.

Paul Waterloo

Thanks for posting, very interesting pictures indeed.

rockhouse66

I don't understand why, with such low leakdown on 5 of 6 cylinders, you would condemn all of the cylinders and pistons. I'm here to learn BTW.

Ahsai

You may have missed it. I borescoped every one of the cylinders and ALL of them are scored. You can see scratches along the stroke. The scratches are formed by the debris stuck between the pistons and the cylinder walls.

So one of my conclusions is leak down test is worthless to id scored cylinders. Your best bet is borescope inspection. Interesting, right?

Ahsai

BTW, cam timing of both banks are at least a few degrees off (retarded).

Durametric reported about -3 degrees @ crank but my actual measurement is closer to double of that. Maybe one of the reasons is the tensioners have leaked down after a few months.

Ahsai

Updates: removed the bank 1 cam cover. It looks like it's been resealed from before and too much sealant was used. Note the old (stock) residual sealant on the mating surfaces. The excessive sealant almost clogged the cams ends.

The cams and journals seem to be in good condition and the last pic shows the initial clean up attempt. Will have a lot more cleaning to do but I just want to put the cover back on in the meantime so no dust/debris can get into the cam housing.

Also found a curved piece of broken metal like 3/8" long which looks like a segment broken off from a round part.

Cuda911

Interesting project, thanks for the update. Do you have a pic of the broken chunk and the location it came off of?

Ahsai

I'll post a photo of that piece tonight. It's not clear where it came from and whether it's just a collateral damage. Next step is to remove the flywheel and the IMSB.

dgjks6

You are my hero. This is a great thread.

Ahsai

Thanks, man! I'm really enjoying this. I hope people don't mind it going too slow. I enjoy taking my time to study all the details and design of each component and also solve each issue one by one as they pop up along the way.

Flat6 Innovations

I could have told you that..

The scored cylinders can be found with a leak down test IF you can park the piston rings just over the scored section of the cylinder and hold it there. Thats very hard to do.

Most of the time a borescope won't even find initial damage, because it occurs below the area where the piston travels. For those situations, one must improvise.

Ahsai

Haha Jake, I'm sure you could have told me everything I've found when it's all said and done. Just like you, I love to collect data myself. It's quite fun when you are able to understand how things work by inspecting the parts and contemplating the design behind.

Ahsai

So this is the offending piece I found at the bottom of the cam cover, the oil inlet port of the scavenge pump in bank 1. It's broken off from something round.

Ahsai

BTW, its curvature seems to fit this 50mm diameter cap. Rod bearing?

Cuda911

I was wondering if it could be from something curved, rather than round, like a piece of chain tensioner paddle?