worn rings???

[German guy]

I installed a Snyders' 61. head and have seen evidence of blow-by' since. A mist of oil under the oil pan that can accumulate enough to drip a little...even after carefully installing a new gasket...a mist of oil coming from the oil filler tube. Nothing dramatic...but it seems to be coming from blow-by. As long as I wipe the surfaces down every once in a while it does not accumulate. The engine runs well and seems pretty tight. ZERO smoke from the exhaust..certainly not blue. Makes me think that it is NOT worn rings...but...any thoughts? Any fixes?

 

[nkaminar]

The higher compression ratio will cause more blow-by. The traditional fix was a road tube. This is a tube that hangs down below the car so that the air flow under the car sucks the fumes and mist out of the engine. It works best if you also have a means to introduce fresh filtered air into the engine to get some cross flow.

Positive crankcase ventilation was invented in WWII to remove vapors from blow-by from engines. In the 1950's it became mandated on all new cars. It is really a good invention as it sucks acid causing vapors out of the crankcase. It also makes a negative pressure in the crankcase that reduces or eliminates leaks.

 

[BRENT in 10-uh-C]

Do a Cylinder Leak-down test at both TDC, -and at BDC on each cylinder. Then report back with your percentages.

 

[Fullraceflathead]

I agree with Brent performing a leak down test will tell you exactly the condition of your engine Performing the leak down test at bottom dead center is gonna require some extra effort though because you're gonna have an intake valve or an exhaust valve partially open at bottom dead center you would need to disconnect the valve timing from the engine the easiest way would be to remove the cam gear that way you can rotate the camshafts so both valves are closed at bottom dead center.

 

[Fullraceflathead]

You want to make sure you're within 1 or 2° of top dead center when doing a leak down test otherwise the engines gonna rotate on you with the air pressure I normally do a leak down test at 100 PSI that way the leakage is the same percentage if it leaks 10 PSIIT's 10% leakage.

 

[Big hammer]

I use full synthetic oils in all of my engines , moderns , lawn mowers , and in my A . Synthetic oils tend to leak past seals and gaskets more than conventional oil . My A with a Synder’s 6.0 - 1 head had some leakage of synthetic oil , I was given some conventional oil and used it in the A , it now doesn’t leak as much !

 

[Bruce of MN]

That leakage doesn't sound too bad to me. I put an old sock over the filler and cap to catch the mist and replace it once in a while. I got new pistons and rings and a fresh rebore last year, so it has little blowby.

 

[Diastole]

The intake valve is not completely closed at BDC. (22 degrees more rotation is required from BDC)

Rotate the crank so the rotor is midway between the lugs. This is the Smoky Mountain Point, SMP. Brace the wrench against the fender to keep the piston in place and prevent it from moving backward. Always do the LeakDown test at the SMP.

Make sure the engine is warm; if it is the rings, lands, etc add a teaspoon of motor oil to the cylinder and retest.

D-n-t-S

Here is a link to the procedure if you are unfamiliar.

https://drive.google.com/file/d/1BX1Srn1f4fELnfuUdMUQDUfiIEMwgC_d/view?usp=drive_link