HV oil pump/too much oil on top Q

[Belgian1979]

Yes ,calibrate as dannobee described. Do not add oil to the cylinder before doing the leak down test for any reason.Then you MUST bring each cylinder being tested to TDC so that when air is introduced both valves are closed and the piston will stay at top of travel. Tip;do not leave a wrench on the crankshaft bolt when introducing ait into cylinder.It matters little if the engine is cold or "hot" . A reasonably healthy engine will definitely have around 5% or less leakage. A really healthy engine will be less than 2%. Open throttle and listen for escaping air. Do the same at the end of header or tailpipe and at any convenient spot to listen in on the crankcase.

Did the test like you guys described. 1 cylinder for the time being is at 15-16%. I compared it to the stock motor that I'm building which is together apart from the carb but hasn't run yet and that has got 25% in cyl 1...that has me stumped, but assume that the stock motor is because of the fact it hasn't been run yet. Don't think that the leakdown % is a very good indicator. Also, I would assume the most leakage would occur through the ring gap and that is bigger when it is cold.

[Belgian1979]

Assuming this engine with high compression & lube consumption had this treatment.

polishing piston rings?
viewtopic.php?f=1&t=64348



The lack of radiused ring talk was deafening.
That drawing looks greatly exaggerated & not close to scale.
What do yours look like?

Any modern ring manufacturer will de-nut you for doing that to their rings. Lightly debur of the end gaps is all that is to be done. That small radius will defeat the purpose the second ring serves which is oil control.

I hear you, cannot change that now.
Anyway took a look at some old rings and some rings that only ran during breakin. The taper on the second ring wears progressively away with the wear. The old one has a shine place on the ring face to about the top of the ring. The not so old one which was used during a breakin after which it came apart again had a shiny area a couple of mm tall on the under side of the second ring. So that taper does wear almost immediately and that wear is way more than the radiused edge caused by the procedure that Vizard prescribes in his book. Anyway trying to figure out if I'm going to take it apart or just do the heads. If I do have it honed and put in new rings, I'm certainly not going to radius hem again like he suggested in that book.

[fabr]

Nothing causes as much confusion as a little bit of knowledge misunderstood . A really good fabricator/mentor/engineer told me that one time. As time went along I found that sometimes it is just easier to let it be than to try explaining . I wish you well finding what you believe is the issue.Best wishes.

[dannobee]

When you had the leakdown tester hooked up, where was the leakage? Where did you hear it leaking? Through the crankcase (valve cover)? Through the intake? Out the exhaust?

[Belgian1979]

When you had the leakdown tester hooked up, where was the leakage? Where did you hear it leaking? Through the crankcase (valve cover)? Through the intake? Out the exhaust?

Valve cover/breather.

[Belgian1979]

Hm, I did the following test: with my tumb over the hose, zeroing it and then taking the tumb off. It only goes to 75% leakdown. Isn't it supposed to show 100% at that point?

[Belgian1979]

Also, when I zero it, it reaches 0 % at only 26 psi. When searching on the internet it seems this should be done at around 100 psi. Cannot get there with this gauge as it puts the needle outside the range and it won't go down when connected up to the engine. Should have know better with these el cheapo tools...

[fabr]

Post a pic of the leak down tester you are using.

[Belgian1979]

Post a pic of the leak down tester you are using.

Same as this one : https://www.ebay.de/itm/Cylinder-Leak-D ... J2EALw_wcB

[In-Tech]

Just to clarify,you will know you are on TDC with both valves closed when the piston does not slam to BDC when air is introduced. Again,DO NOT leave any wrenches on whatever you used to turn engine to TDC when introducing air.

Ummmmm, why not? You only have to do that once to learn your lesson

[fabr]

Just to clarify,you will know you are on TDC with both valves closed when the piston does not slam to BDC when air is introduced. Again,DO NOT leave any wrenches on whatever you used to turn engine to TDC when introducing air.

T
Ummmmm, why not? You only have to do that once to learn your lesson

Unless you are an idiot like me !!

[Belgian1979]

Did a different test. I took off the gauge with the leakdown rates and moved the first gauge to its location and plugged the first hole. Then calibrated it to 100 psi and plugged it in. It then read 93 psi. Which means that I have about 7% leakdown. I would consider that to be good. Still have to test the others though.

[rebelyell]

JME Still don't think HV pump help most apps; perhaps hurts this one. Suggest consider a pump with a larger pickup tube diameter. GM did just that about 1993; increased from 5/8" M55 to 3/4" M155 (std vol, std pres). Larger OD tube helps pump suck and helps stabilize low-mid performance. YMMV

If ya insist, there's an M155HV as well.

[Belgian1979]

Ok, thanks. Tested all others and leakdown is 7-8%

[1980RS]

I had 2 engine with stock type oil pans that I used HV pumps with, both had problems with oil everywhere it's not supposed to be. My peanut port engine had oil pooling on top of the pistons and I replaced it with a Std. volume pump, the next time I pulled the heads everything looked great inside. Have a 350 SBC that is the same way, no need for a HV in most engines. As a matter of fact that is what GM uses in the LS AFM engines with the lifter troubles and that HV seems to do the same thing, slinging oil everywhere.