Thread: blower w troubles

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i have a 73 350 all set up with a 871 b&m blower when i crank on it about 5500 rpms or so i blow oil all in my engine compartment not pretty looks like im building crank pressure i have it breathing gd would it be my exhaust its only 2 1/4 o.d. tried lots of stuff anybody have any sug. thks kipster

sounds like to me your blower boost is by-passing your rings and going into the pan, and blowing the oil out of the motor. i believe your rings are shot. need to do a leak down test.

Originally Posted by lt1s10

sounds like to me your blower boost is by-passing your rings and going into the pan, and blowing the oil out of the motor. i believe your rings are shot. need to do a leak down test.

Bingo.

i did a compression check and all cyl. have 100 psi would that still show ring problems

Originally Posted by kipster40

i did a compression check and all cyl. have 100 psi would that still show ring problems

dont know much bout blower motors but i'd say that 100 psi is a problem . i'd like to build 1 someday and maybe i should read on this be4 i reply

Originally Posted by kipster40

i did a compression check and all cyl. have 100 psi would that still show ring problems

At 100 PSI compression, I would think the puffers doing a fine job of boosting the crankcase. With the compression being that consistant, I'd say it's a ring problem.

Art

Originally Posted by kipster40

i did a compression check and all cyl. have 100 psi would that still show ring problems

100 lbs is not enough, sounds like to me the motor has gotten hot one time to many and collapsed the rings.

Isn't the pressure you'll read a function of the compression ratio you're running as well as cam timing? Assuming the rings are good, what pressure would be expected on a 7:1 blower motor with a healthy cam?

Regards, Mark

Originally Posted by MAW

Isn't the pressure you'll read a function of the compression ratio you're running as well as cam timing? Assuming the rings are good, what pressure would be expected on a 7:1 blower motor with a healthy cam?

Regards, Mark

yes this was what i was thinking to he did not give us much on the build 100 psi may be a bit low but who knows what cr he hase or what cam lsa is . 100 psi may be all it hase?

Originally Posted by pat mccarthy

yes this was what i was thinking to he did not give us much on the build 100 psi may be a bit low but who knows what cr he hase or what cam lsa is . 100 psi may be all it hase?

the ? is not how much comp. the motor has, its how much comp. will the rings hold, you do a leak down test and you rings want hold 100 lbs. of air then you dont have much. he has boost getting in the pan and the only way its gonna get there is its by-passing something.

what valve covers do you have are they baffled you say it is vented good what type of breathers ? and how about the oil pan dose it have a scraper windage tray ? all this will add up to alot of oil on the top of the engine if any of this stuff is not rigth or not their and the blower will add to it i think any breather system has to be much better than you may think that is good i have see this with big engines and blower cars and the piston rings may be on up side down

ok yes but did he do a leak down test and are you sure what is he got going on this ? bad ring ok may be but? at this point oil on the top of the engine could be from many thing and yes ring s to

yep no need to do a leak down test if you can turn it over with a open end 5/8 wench with the plugs in

so whats the easiest way to find my problem leak test, pull the heads to look at the rings,this was a running motor before i put it in my 40.so sittin for a year or so cause this?were should i go to have a leak test done any sugg?

if u can see the rings when u pulled the heads u have bigger problems. my suggestion is re-ring it. and another thing i'd try after re-ringing it is evac tubes from your header collector but u need 2 baffeled tappet covers this will help pull crank case pressure.