7R02K motor

getlive65_old · August 12, 2008 at 10:29 AM

Hello everyone! I've been stuck on the vmf forum and haven't posted on here in quite some time. My car is finally running and driving so I'll include pictures and a video, but it's not doing so well.

My car has had blowby since i first got it running. At higher rpm's/freeway speeds it comes out of the dipstick AND driver side breather, enough to spray out of my teardrop hood vent and onto my window.

My pcv valve is working, it sucks like it should.

Compression test results: (right after driving, all plugs out, 5 cycles each cyl)

cyl 1) 135

cyl 2) 135

cyl 3) 110

cyl 4) 116

cyl 5) 140

cyl 6) 116

cyl 7) 122

cyl 114

The car pulls very strong and feels great. BUT, this blowby is killing me...it's slowly making a mess in my engine compartment as well. The heads have a fresh build, timing chain, and the rest of the top end is new. The cam, and everything below the heads is unknown, besides the fact that it's a .40 over 7R02K.

This is how much blowby i'm getting.

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It feels and sounds great, but is this engine on it's last leg? Any ideas?

I still have the water pump, timing chain and cover, cobra intake, valve covers and other various parts I have replaced on the engine, but I'm starting to consider getting rid of it (the engine).

here's the car...

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CharlesTurner · August 12, 2008 at 10:42 AM

Are you running a stock oil pump?

getlive65_old · August 12, 2008 at 10:55 AM

I'm not sure what oil pump this is. I haven't changed it, but maybe somebody else did?

[Blocked Image: http://i37.photobucket.com/albums/e73/shitentenemusu/IMG_3783.jpg]

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CharlesTurner · August 12, 2008 at 11:58 AM

Hard to tell from the pics.

If you have a stock oil pump, can compare insides.

Donsk65_old · August 12, 2008 at 1:09 PM

Looks like bearing wear on the oil screen ??

boss1_old · August 12, 2008 at 2:08 PM

Most likely weak ring seal from an older engine.

Additionally...just because the heads were done, does not mean they were done right. In fact, I would guess the valves are not seating properly. It is extremely difficult to find competent engine builders these days.

135-140 PSI sounds good, but three of your cylinders are weak.

oscart_old · August 12, 2008 at 2:42 PM

Try running a good set of vented valve cover breathers and make sure you PCV system is working and routed correctly. This will help with releave some of the crank case pressure.

getlive65_old · August 12, 2008 at 3:49 PM

I don't have a stock pump to compare it to, but would that be a cause of blowby?

The engine didn't run for at least couple of years before I got it. This picture was taken during at that time also, so maybe that is why it looks a little funny.

The heads were built by a reputable shop, but as you mentioned, it's still hard to get a good job done. I'm leaning toward (not happily) ring seal wear, but is there a way I can test to see if it's the piston rings or the valves not seating properly? Am I contradicting myself?? I'm not an expert with engines by any means.

I have a driver side breather and my pcv system is working.

KPHartley_old · August 12, 2008 at 7:11 PM

If the engine sat for a few years, I would look towards a stuck ring or two in the weak compression cylinders. When an engine sits like that the steel rings and the aluminum pistons corrode/rust due to moisture and electrolisis between the two dissimlar metals. Your rings just due not float in the bore (Stuck in the piston) which allows the compression (BlowBy) into the top of the head and out the breather.

Ken

63Kcode_old · August 12, 2008 at 7:49 PM

The one piston skirt that I can see looks very worn. I would say it's time to rebuild the bottom end.

Larry

C6ZZKGT · August 13, 2008 at 9:06 AM Official Post

Whenever you do a valve job on an older short block, this will accent any weaknesses in the rings. I agree with Ken that you probably have some stuck rings and as Larry says, it is time to rebuild the bottom end.

-Fred-

getlive65_old · August 13, 2008 at 10:28 AM

Thank you guys. I appreciate all of the input. The heads have a fresh rebuild, so it makes sense the bottom end flaws will show.

but with a .40 over 289 block, is it worth rebuilding? I've heard of sleeving the cylinders... but I don't know much about it.

C6ZZKGT · August 13, 2008 at 11:56 AM Official Post

You will need to check the taper and out of round conditions of the cylinders. If they are within specs, a rering will work out fine.

-Fred-

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