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Just built a 2021cc:

92mm AA TW cylinders Hypereutectic pistons
Total Seal 2nd ring
Web 218 cam 112LSA
Panchito Heads
Megasquirt
Meth injection
15 lbs of boost.

It runs good, but now I'm getting excessive crankcase pressure. I have the heads and oil fill tower vented to a high mounted breather box, and I can visibly see the crankcase pressure puffing out of it, and it's pushing a bit of oil out of the front of the crank, behind the pulley.

I broke in the motor by running it at 2000 rpms for 15 min, with SAE 30 weight oil. I started putting a 7-8 lbs of boost on it pretty soon after that. I put about 75-100 miles on it then realized the clutch was slipping under high boost. I pulled the motor and put and put a KEP stage 2 and a dual friction disc in it. I also changed the oil and put Valvoline VR1 20W50 in it. No more slippage, and it runs like a monster on boost. Now I'm getting excessive crankcase pressure.

Thoughts? Did I start running boost too soon??

Sure sounds like too soon ,rings didn't seat enough, you may have to tear down and hone the cylinders may as well toss new rings in it too.
But do try to seat the rings first before all that work

I've always thought a leakdown test should be a good way to tell when the rings have seated, not some magical number of miles.

Max

I used The Total Seal Quickseat stuff on the cylinders. I'm going to do a compression test this weekend and see how that looks.

Sideswipe wrote:I used The Total Seal Quickseat stuff on the cylinders. I'm going to do a compression test this weekend and see how that looks.

I've used the same stuff on a few motors with good luck(even with chrome rings), I still put a little oil in the ring lands though and spin my rings around to lube the sides of the rings

I boost mine right away. They say with N/A to find a hill and put a load on it. I figure, what's more of a load than some boost?! I don't Max it out, but i do run wastegate.

V8Nate wrote: ↑Wed Jan 27, 2021 2:34 pm

Sideswipe wrote:I used The Total Seal Quickseat stuff on the cylinders. I'm going to do a compression test this weekend and see how that looks.

I've used the same stuff on a few motors with good luck(even with chrome rings), I still put a little oil in the ring lands though and spin my rings around to lube the sides of the rings

Yeah, I oiled the ring lands as well. I gapped the rings as recommended for turbo use, and indexed them per the Total Seal recommendation.

I boost 6 lbs at around 3 miles.....I don't beat on it but I drive it like normal after 10-15 miles.

What is your tune like??? Any chance of detonation??? What are your ring gaps???

Blow by can be caused by detonation which will put minute cracks in the pistons. It can also crack the ring lands and take chunks out.

If I see blow by where there was none before I take the car off the road and put new P/C's on it.

For 180 bucks it just ain't worth dinking with honing and buying rings and taking a chance it was the piston anyways.

Why are you using such thick oil? 10w30 would be much better on a fresh motor. I always give the cylinders a quick hone(especially new ones) to provide a better finish which helps with seating and wear. Hope you find the problem.

X2 with Ken, that oil is thick , heck even in the summer I've only used 10w 40,,,

I broke-in my fresh 1600 on boost. I removed the boost controller and ran strait wastegate (5 psi). I think the most critical part of breaking in a fresh ACVW is the initial 20 min / 2000 rpm cam break-in. I used cheap 30W and Cam break-in additive. Replaced oil with fresh 30W and more cam additive and drove 500 miles (occasional pull to 5K on 5 psi) and changed oil again. Filled with 15W40 Rotella and called it done. Now I'm on 10-15psi boost and all is well.

-Nick-

I just did a compression test. Cylinders 1,2,4 are 130-140 psi. Cylinder 3 is like 45 psi. I'm pretty sure I have a broken ring....damnit

Bummer. But that's part of the experience. Pull it apart and see what you have going on. That is too fun of an engine to let it sit down!

P/C's are cheap.....replace them and move on......Any change in an engine.......be it compression or more blowby is a warning to check it.
I've replaced them 3 times without even thinking about it too much. It's not worth taking a chance and blowing the case to pieces due to a cracked piston. They should be considered consumables. I have not been able to see any cracks in the pistons but the blow by is gone once replaced.

Tuning ain't easy...especially while learning what an engine needs to make power and hold together. Once you learn IAT's are one of the most important issues...along with afr's... you can tune your ignition to make the engine last.
You really need to keep IAT's below 130* F. and have a conservative ignition map. Depending on ambient air temps and boost level I would not be much above 20 degrees timing at 8 lbs boost.
If you have w/I and/or intercooler things will be different.

sorry for your trublems do let us know what's up?
I just built my 2074 with the same piston & cylinders