blow by

[arobunson]

i have a sbc 408 with lot of blow back pressure, motor is kind of new just been together for 3 months lot of white smoke coming from breather cap what could this be thanks

[bjuice]

Its oil getting past your rings..some HP Race motors are built loose and could possible have some minor blow by....thats why a vaccum pump is highly recommended/required..

if you do not have $600.00 to invest in a vaccum pump..at least install some e-vac tubes in the headers

hard to tell by internet how bad your blow-by is...so i am just making a general statement here..

but its oil getting thru

Brian

[zipper06]

White smoke may indicate a water leak, being it's a 400 blk. they are notorious for blown head gaskets. Have you noticed any milking of the oil?

JMO

Zip.

[arobunson]

no water in oil thanks

[hink]

400 blocks if they are not plate honed with the same hardware it will show alot of blow by and if your building a lot of cylinder pressure its even worse.

Do a leak down test.

[arobunson]

ok compression check #1-190, #3-135,#5-0, #7-230, #2-220, #4-225, #6-220, #8-230 could it be rings or head problem

[hink]

ok compression check #1-190, #3-135,#5-0, #7-230, #2-220, #4-225, #6-220, #8-230 could it be rings or head problem

You really need to do a leak down test!!!!!!!!

[cepx111]

Take the head off on the drivers side, the problem should be quite evident since you have "ZERO" compression on number 5 cylinder.
My money has it that you have a hole in the top of your piston.
Goodluck, Charles

[hink]

ok compression check #1-190, #3-135,#5-0, #7-230, #2-220, #4-225, #6-220, #8-230 could it be rings or head problem

You maybe looking at a bent valve!!!!!!

[suicidebomb]

I once forgot to install the #5 piston, but I knew right off, somthing was amiss, rod made a terrible clatter.

[Tod74]

I once forgot to install the #5 piston, but I knew right off, somthing was amiss, rod made a terrible clatter.


:?

[bjuice]

I once forgot to install the #5 piston, but I knew right off, somthing was amiss, rod made a terrible clatter.

i hear ya.. 8) and i forgot to install my crank on my last build also..LOL...Good one ! :D

[Tod74]

you guys need to leave the beer in the fridge until the heads are on. :shock:

:P

[zipper06]

I once forgot to install the #5 piston, but I knew right off, somthing was amiss, rod made a terrible clatter.

i hear ya.. 8) and i forgot to install my crank on my last build also..LOL...Good one ! :D

Damn what did you hook the fly wheel to? the harmonic balancer, bet that sucker was hard to start

:P

[bjuice]

very low tension...LOL