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Beau Dirt
Beau Dirt
Minneapolis, MN
(35 posts)

Registered:
05/02/2012 03:23AM

Main British Car:
1973 Morris Mini, 1930 ford Model T, 1926 Model T 1 liter Suzuki and Four 215's

Olds 215 compression numbers, low oil pressure and blowby.
Posted by: Beau Dirt
Date: April 16, 2016 11:20AM

So I'm trying to track down blow by and low oil pressure problems on my 215.

I did a compression check today. I checked it cold, and dry. 1- 110 psi, 3- 115 psi, 5- 115 psi, 7-115 psi, 2- 115 psi, 4- 120 psi, 6- 105 psi, 8- 115 psi. I can't confirm that my old compression gauge is accurate, and I was only able to get it as tight as I could by hand since I could sneak a wrench in to tighten it up tight.

These numbers seem low.

I'm currently running Offy valve covers with a breather in each cover, no PCV or draft tube. I have good pressure when the engine is cold, and it slowly drops to around 15 psi, and to 0 after it's ran a while. I'm also getting oil out of the dipstick tube.

The engine was said to be "rebuilt" by the past owner, but after he reinstalled it he said it had no oil pressure at all. I figured he just didn't prime the system. He mentioned that he had filled the crankcase with gas due to a faulty carb.

Are my rings toast? Are the main bearing more than likely loose?



Edited 1 time(s). Last edit at 04/16/2016 11:23AM by Beau Dirt.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5759 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: BlownMGB-V8
Date: April 16, 2016 11:27AM

If it isn't smoking and/or smells like oil I wouldn't worry too much. Those numbers are about right for a low compression engine. Proper PCV plumbing will handle your blowby. For the low oil pressure you could tighten up the clearances in your oil pump, install a stiffer bypass spring and even enlarge the pump inlet passages. Or you could run 50 wt oil.

Jim


Beau Dirt
Beau Dirt
Minneapolis, MN
(35 posts)

Registered:
05/02/2012 03:23AM

Main British Car:
1973 Morris Mini, 1930 ford Model T, 1926 Model T 1 liter Suzuki and Four 215's

Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: Beau Dirt
Date: April 16, 2016 01:05PM

This is the 185hp 4-barrel engine.

No smoking or oil burning. I see a little oil dripping from the flywheel cover but I'm wondering if that is just the crankcase pressure trying to release.

When I put the front cover back on the engine I installed the steel thrust plate thing between the pump and front cover. I'm not real sure where to measure the clearance though, so I installed it with a gasket on each side of the steel plate. I'm running Castrol GTX 20w-50 oil.The engine will have 60-80 psi at start up. It used to drop to about 15-20 after being warm and now I have nothing after a while of running and I hear lifter noise. Having some sort of oil pressure makes me think the pump is working but I don't know. I do sheet metal and not engine stuff.

My idea was to run the breather I have on the passenger side, and punch a hole in the drivers side breather and install a PCV valve. I have searched this forum a bunch on PCV info and have read many of your replies. I just need to track down a proper PCV valve now.

EDIT- I pulled the spring out you were talking about and stretched it out a little to see if it helped. After warm up the gauge reads about 5 psi now, instead of nothing. I think I might have to pull the oil pump and and do a rebuild. I have a half dozen pumps around so I hope to have one good one.



Edited 4 time(s). Last edit at 04/16/2016 01:49PM by Beau Dirt.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5759 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: BlownMGB-V8
Date: April 16, 2016 04:16PM

You should assemble the pump so that it has minimal end clearance on the gears. I like to have the gears just drag a tiny bit after assembly with new parts but with parts that have been run in, just shy of that. Shooting for less than .001" end clearance. The clearance opens up as it gets warm. You can port the booster plate and pump inlet, search "oiling mods".

The engine may not have been rebuilt with 4bbl Buick pistons. They were not available for a long time and still may not be. Lots of rebuilds were done with the 2bbl pistons.

Jim


88v8
Ivor Duarte
Gloucestershire UK
(629 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: 88v8
Date: April 17, 2016 04:57AM

The oil pump, the end float between gears and cover is critical. If the gasket is too thick that makes a big difference.
At one time, Landrover over here were selllng overly thick gaskets.

Having said that, I can't actually say what the thickness should be.
But these chaps could.
[www.v8wizard.com]

Ivor


tr8todd
Todd Kishbach

(351 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: tr8todd
Date: April 17, 2016 06:58AM

If the cylinders got washed down with fuel and were run that way, the hash marks on the cylinder walls may have worn flat and vertical score marks may have formed. These hash marks are there to hold a little bit of oil and aid in sealing the piston rings. I've seen several engines with cams that were too aggressive and had a propensity to dump excess fuel at lower rpms do this. Most of these engines were stroker engines where the owners wanted an all out street engine. These engines had way too much excess crankcase pressure at relatively low miles. Were talking blow the gaskets out, blow the dipstick out kind of pressure. If you have access to a boroscope, stick it in there and have a look at the cylinder walls. Secondly on the low oil pressure issue. Take a look inside the cover where the oil pump gears sit. The steel gears will often wear deep circles in bothe pump cover and the pump housing cast into the front cover. At lower rpms, the gears move slower and the oil squeezes by these grooves instead of circulating around the engine. If they are bad enough, you should replace the front cover.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5759 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: BlownMGB-V8
Date: April 17, 2016 11:41AM

TAPerformance sells a pump gasket shim kit which is very useful in setting up the oil pump. The inlet oil passage in the block can be drilled out to 5/8" and a 5/8" pickup installed. Corners should be radiused. This can be done with the engine in the car. Also, try straight 50 wt racing oil.

Jim



Edited 1 time(s). Last edit at 04/17/2016 11:42AM by BlownMGB-V8.



roverman
Art Gertz
Winchester, CA.
(2974 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: roverman
Date: April 20, 2016 10:57AM

Beau, To be better informed, I suggest a "wet" compression test. Squirt a "little" oil , in each cylinder and test. If rings aren't sealing properly, compression will test higher, (oil make a temp. ring seal). You can check oil pump gear, end clearance with "plastigage". Good Luck, roverman.


Beau Dirt
Beau Dirt
Minneapolis, MN
(35 posts)

Registered:
05/02/2012 03:23AM

Main British Car:
1973 Morris Mini, 1930 ford Model T, 1926 Model T 1 liter Suzuki and Four 215's

Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: Beau Dirt
Date: May 02, 2016 11:52PM

So a few things. I have a pcv hooked up now. The engine doesn't appear to blue oil out of the dipstick now. I was getting a lot of lifter noise out of the drivers side rockers. I pulled both covers. All of the intake rocker arms ate dry and not pumping oil. The exhaust side was fine though. Passenger side if working as it should. I put 30 weight oil in as recommended by a friend. Didn't make a difference. I tried a different gauge and also nothing different. It is at about 5 psi at idle when the engine is at idle and at about 180 warm. I have been too lazy to pull the oil pump or wet test the compression. I will try and do that this weekend. Any thoughts on the lack of oil in the itake rockers?


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5759 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: BlownMGB-V8
Date: May 03, 2016 10:11AM

You could pull the rocker shafts and inspect them. If oil is getting to some of the rockers but not others that just about has to be where the trouble is. Depending on what sort of rebuild was done by the PO it may have the original rockers and shafts. They wear on the bottom and can give erratic oiling as a result. I've seen a good 1mm of shaft wear under the rockers before, and that can also cause lifter tap.

Jim


Beau Dirt
Beau Dirt
Minneapolis, MN
(35 posts)

Registered:
05/02/2012 03:23AM

Main British Car:
1973 Morris Mini, 1930 ford Model T, 1926 Model T 1 liter Suzuki and Four 215's

Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: Beau Dirt
Date: May 03, 2016 08:47PM

Jim, thank you very much.

I traded all my spare engines an parts for another 185hp engine this past week. If I can't get this figured out hopefully the spare engine will get me through the season while I do a quality rebuild. The PO of this engine was a cheap ass and I doubt he did anything more than what he thought he had to. The worn timing chain/gears and channel lock marks on the cam shaft made me wonder right away. :(


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5759 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Olds 215 compression numbers, low oil pressure and blowby.
Posted by: BlownMGB-V8
Date: May 04, 2016 01:47AM

It's really more about quality of workmanship then money, though a bit spent in the right places can make a big difference. With these engines, oil control is very important. Tight clearances really pay off, if you build a tight engine and pay attention to the oiling system, oil pressure should never be a problem.

Jim


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