underpsi68

Thanks I'll keep that in mind. I really don't want to run a vac pump, nor should I have to. But might be enough where I have no problems.

underpsi68

Forgot to mention that I was thinking engine is being loaded different on dyno vs in car. On dyno I'm assuming they put some load to warm it up(less intake vac). In the car the engine pulls 15" vac at idle and 16-17" at 2100rpm cruise. Thinking the higher vac is causing the oil to get sucked past the rings.

Problem also seems to happen worse after I ran it hard- (boost) or right after during hard decel- very high vac. Sucking past the rings.

Any thoughts on this?

BillK

If it was rings it would be doing it on the dyno too. If anything the extra boost from the turbo would be increasing blowby but that would not make it get oil on the tops of the pistons. I probably do an average of two to three blocks a week and I finish them all with a 280 grit stone followed by a few strokes with plateau finishing brushes. The bores are very smooth and I have had absolutely no issues with ring sealing. I used a profilometer on it and sent the scan to Total Seal and they said it was perfect.

I dont even see a 320 grit Sunnen hone stone available ? Maybe a "dingleberry" type ? As many issues as you have been having I would hope that you would have the block honed in a "real" hone. The walls look like they could use it any way.

I guess you have the engine back apart otherwise I would tell you to put some die in the oil and run it a few more times. Then when you take it apart you might be able to see where the oil is coming from.

articfriends

iTrader: (1)

Pm me price, details, I been wanting to buy one to play with on my dyno, you ever used one (electric i mean), Thanks, Smitty

ALL_IN!

iTrader: (1)

Maybe you mentioned it already, but when does that smoke actually occur? On accel or decel?
You mention the guides were not replaced, but were the valves replaced? If so, do you have data that shows actual valve guide clearance (did they measure guides and measure valves that were installed?)
Smoke on decel generally indicates excessive valve guide clearance/wear or a valve seal issue, in an extreme case.
Terry

zz28zz

Seeing any oil in the intake runners?

SB

iTrader: (1)

Look at the pics. There is a pantload.

Amazing to me, anyway.

zz28zz

Guess I should have said runners in the intake manifold as opposed to in the head. I do see oil in the intake runners of the heads. Reason I asked was if a malfunctioning PCV sys ( if present) might be responsible for oil burning. Kinda lines up with "after a hard run" (elevated crankcase press) and "heavy deceleration" (super high intake vacuum). Just a thought.

underpsi68

Block had a real hone each and every time. My concern is the hone is to fine, even the one I just got last week from a different shop. New shop and I guessed old hone was a 400 finish. When I went to pick up block last week I asked what the finish was because it looked very fine to me again. He said 320 or like 320, don't remember exactly what his words were. I'm going to call him and ask if he can tell me what stone he used. That will at least let me know what is there. He did say he did 2 final strokes each cylinder.
What bothers me is I think the finish is too fine. Even you said you do a 280grit. When I called up Mahle rings this past week the tech said 280. Said 320 was to fine. This is with plasma moly rings. Attached is a few pictures of latest hone. Honestly the finish is MUCH finer in person than the camera is capturing. You can barely feel it with your finger nail. I wish you were
closer Bill. I would ask you to take a look at it. You are about 4 1/2hrs away from me. But at this point I would like to get to the bottom of my issue. I'm in ny. I did drive to NJ for what I believe is a very reputable shop.

underpsi68

Honestly I'm not 100% sure when it happens. In the past it seemed like it was there after getting on it, so it could be cylinder pressure or hi vac on decel, not really sure.

Guides weren't changed, only exhaust valves are new. After first build I disassembled the heads and found 2 valves that were snug in the guides, no damage or galing. When I dropped engine off I brought heads to have builder look at. He said the other 14 guides measured .0012 clearance. I told him to loosen them up a bit do to the heat of the turbo. They are now .0016-0018. He said that was more than safe for a street car.