[461-69bird]

I got the following readings with my cheapo tester. It might not be the most accurate tester, but I suppose it's consistent.
There is air escaping from the dipstick tube but I don't know if that's normal for these readings.

1 = 20%
3 = 20%
5 = 20%
7 = 19%

2 = 20%
4 = 19%
6 = 20%
8 = 19%

Are the amounts enough to push oil out if the dipstick at high revs? I've had to disconnect my pcv as it sucked oil, then it pushed oil out the dipstick with the pcv capped.

[steve25]

Did you not have this all redone due to a builders error or some problem, I can’t recall?

Anyway even if that tester is not 100% on the money you’ve got problems like your dip stick is letting you know with its actions along with hearing air bleeding into the crankcase.

Was the motor warmed up when you did these test?

[461-69bird]

Steve, no this is a fresh build that has dyno runs for cam break in, ring seal and power pulls. About 30 road miles, it's been having problems either sucking oil through the pcv or blowing out the dipstick.

Engine was warm when I did the test.

So do you think I can go back to the builder and say there is a problem with the rings after seeing these readings?

[GOAT8U2]

I've learned a lesson here and do this now...

You have to get the engine shop to break in the engine, then give you the static and leak down numbers after. This is then dated and documented.

Then you pretend like that never happened and you pay a shop to do the exact same thing right after and compare. If the engine shop did it right after running, then you have the 2nd shop so the same. This gives you big ammo in the guns if needed.

Those numbers are rough IMO, mine were 6 @ 15% and 2 @ 13% and that was the last of my new engine concerns after finding mains and rods out of spec.

[461-69bird]

Just spoke to the builder and he's unsure of the reason. He uses Total Seal rings if that's relevant.
He wants me to go on a road trip to put some miles on it then do another test to see if the numbers improve, if not I've got to take the engine back to him for investigation.

[steve25]

Don’t go on a road trip!

Did you explain to the builder that you hear air getting into the crankcase?

Do this.

Tape down your dip stick and make 4 to 5 full throttle blast up to 5500 rpm thru all the gears you have, then do a hot leak down test again.

If after that no large improvement is seen then I am sorry to say that you have problems.

Was this motor overbored with a torque plate?

[opeliac]

We have an all aluminum 632 chevy NITROUS engine that BES did for us...Before the engine was ever started, I leaked it down...None were above 9%...Once I started it and warmed it up, then let it cool completely down, none were over 8%...This is a 4.625 bore, with ring gaps for heavy doses of nitrous...I ALWAYS leak mine ice cold, just so there is no variables...If you warm it up first, there is no way to keep the temperature the same throughout testing all 8 cylinders...

After a season of abuse, we had 1 that got to 21%, and IMO, that was because of it getting on the rev limiter hard while still on the juice when we broke an input shaft...I understand why the builder wants you to drive it, but thats not something that i'd be good with...I have never had an engine that wouldnt seal up immediately, with proper wall finish...

[Elarson]

Originally Posted by 461-69bird

I got the following readings with my cheapo tester. It might not be the most accurate tester, but I suppose it's consistent.
There is air escaping from the dipstick tube but I don't know if that's normal for these readings.

1 = 20%
3 = 20%
5 = 20%
7 = 19%

2 = 20%
4 = 19%
6 = 20%
8 = 19%

Are the amounts enough to push oil out if the dipstick at high revs? I've had to disconnect my pcv as it sucked oil, then it pushed oil out the dipstick with the pcv capped.

I like that all cylinders are within 1% of each other That suggests that there is no local problem like a leaking valve, damaged piston, etc. So that narrows the probabilities to 2 things:

1) first and foremost you said you used a cheapo tester. The test results are intimately connected to what kind of metering orifice is in the tester and whether the tester has any leaks at the spark plug hole, etc. The first thing I'd do is find a source for a professional quality leakdown tester and retest everything. Do the test with the engine warm, as Steve25 suggested.

2) there is a uniform problem with all 8 cylinders, such as a poor ring seal caused by a consistently incorrect cylinder surface, etc.

Good luck and report back.

Eric

[461-69bird]

Yes told him about the air in the crankcase.

So quick blasts would be better than a long trip?

I didn't think you do the test cold?

[steve25]

In your case do the second test the same way you did the first leak down test so you have consistency and can have the best comparison.

Yes, it seems your engine builder want to see if the rings need more run in time, unfortunately cruise time does not load the rings enough to get that done even in 300 miles .

Also I have a a few real big questions at this point!

If as you have posted the motor was run on the dyno for cam break in and however many power pulls, then why was the dip stick not blowing out then?

Did you attend the dyno sessions and not see a dip stick issue taking place then?


Why was a leak down test not done by the builder at that time so you would have a base line record for you files on the motor?

[Formulas]

Are you running a breather on a valve cover if not where do you expect crankcase pressure to go every engine has some

Also did you use recomended break in oil from your builder?

Cheap leakdown testers will give bogus readings

How is the timing curve? could be to far advanced rattleing the rings

[461-69bird]

There's a breather on each valve cover. Break in was done by builder on the dyno then he filled it with VP 10/30, which is what's still in it after only 30 road miles.
Same MSD mech adv dizzy set up as last engine, 18 initial, 34 total all in by 3000.

I didn't attend the dyno session and he's telling me he didn't see any issues at the time. Don't know why he doesn't do leakdown tests afterwards.

All I've done since the build is install it, hook up my exhaust system, check the timing and drive it locally.

[461-69bird]

Eric, sorry missed your reply. I thought about trying to borrow a good one and see if there's a difference. I'm leaning towards a ring problem because of the readings across all 8 cylinders.
Bores were cleaned up only, no re bore, then existing pistons installed with new rings, is it possible too much was done and the rings are not sealing because of it?

[Half-Inch Stud]

Originally Posted by 461-69bird

Just spoke to the builder and he's unsure of the reason. He uses Total Seal rings if that's relevant.
He wants me to go on a road trip to put some miles on it then do another test to see if the numbers improve, if not I've got to take the engine back to him for investigation.

Yikes. Sounds like Gapless. Skip the road trip. Is the builder an expert on those particular Gapless rings, and did he provide guidance on (cam and rings) break-in without or with PCV connected?. You got smoke out the tailpipe??

My bad experience with gapless rings was around 1992; all 8 cyls scored after a brief, mild break-in. I built it the regular ways that worked, but used the gapless rings needed something (subtle?) that I never understood. I went to a Pontiac rebuilder to recover the block. He had particular advice for break-in with Gapless rings. We went with regular rings on the recovery rebuild and that was nice.

[Half-Inch Stud]

Originally Posted by 461-69bird

......Bores were cleaned up only, no re bore, then existing pistons installed with new rings, is it possible too much was done and the rings are not sealing because of it?

Maybe i am assuming: Total Seal Gapless rings? Or just regular rings from Total Seal ?

The " Gapless" 2nd Ring design is peculiar (i think) to any typical wall prep, versus a recommended wall prep (i dunno what)
https://www.totalseal.com/support-and-downloads

+ a "Quickseat dry-lube powder" + ( an inactive or active PCV deal, i dunno) + dinasaur oil during break-in, for a probable win.

[steve25]

Just because a particular brand and or set of rings will work with your bore size and allow the needed gap, a ring is only the right size for a ring groove when the ring can be pushed in and hide in the groove no more then .005” at room temp.

If your build has more then this amount then you have the wrong rings be they gap less style or not.

I am sure by the posted about new motor blow by conditions I see posted on this site and many others that all too many home assemblers and even shops that build motors do not make this simple check and address it!

Speed pro offers ring groove shim stock for 1/16” and 5/64” rings in a .018” thickness to crutch this bad situation.

Also if your running used pistons’ and especially cast ones, if your top to bottom ring groove clearance is .004” or more then that’s a mess also in terms of blow by .

To me now with the further details that the OP has posted about his motor I think his block has quite a few bores out of round making for his issue.

I hope I am wrong, but if his engine builder saw this he never should have allow the motor to be re-ringed and slapped back together when it needed to be bored.

I once worked for a shop and when the owner of a motor that was in such a condition wanted to go the easy cheap route he then signed a form that released the shop from any liability.

[461-69bird]

I forgot to ask if they were gapless, hoping not.
Pistons are forged.
He's assured me the bores were all parallel after coming back from his machinist.

[steve25]

So the person who put it together for you was not the machinist ?

There’s nothing wrong with gap less rings if such was used properly.

[461-69bird]

No Steve, the builder has a machinist who does all his work, he then checks the dimensions before assembly is what I'm told.