Low Oil pressure problem on rebuilt 350 - Team Camaro Tech
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post #1 of 13 (permalink) Old Mar 11th, 01, 02:50 PM Thread Starter
 
Join Date: Mar 2001
Location: Cypress, California
Posts: 8
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Hi all,
I just recently joined this group in hopes that someone might be able
to help me out with a big problem I am having.

I own a 1976 Camaro RS, 350 with a 4-barrel Quad. I recently had the
engine rebuilt, only has start time and less than 50 miles on it from
puttering up and down my street with it. Just yesterday I noticed
that at idle with the engine fully warmed up my oil pressure light on
the dash was flickering. I immediately shut it down and went down to
the auto parts store and bought a mechanical oil pressure gauge.

With the mechanical gauge installed, pressure on startup (cold)
looked OK at around 55-60 psi. Once she started to warm up though it
really started to drop. Fully warmed up, the gauge registered about
8psi in neutral or park, and about 5psi idling in gear. Needless to
say, I am very concerned about this.

One thing I did notice, the line going to my mechanical oil pressure
gauge (semi-transparent white color) has oil in it as it should, but
there also seems to be air in the line, as I can see gaps of white in
the otherwise black line. Air in the oil?

I have checked the oil level, and it is fine. I have not yet pulled
the oil pan and checked the pump or it's screen.. I have a feeling
that will be next though. I'm praying that this doesn't end up being
a case of the engine rebuilder throwing an undersize cam in with
standard bearings or something of that nature. Any suggestions or
advice is greatly appreciated! Thanks in advance ---

Chris May
Cypress, CA
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post #2 of 13 (permalink) Old Mar 11th, 01, 02:58 PM
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Join Date: Jun 2000
Location: Houston, Texas
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What weight of oil are you using? You could try going to thicker oil but I would have to agree with the excessive clearance idea you already have. Could be the pickup has fallen off the oil pump but you don't have many miles on the motor yet for that to happen.
Stephen

------------------
67 RS/SS 350 700R4
69 SS clone unfinished
72 454 Weekend Racer

[This message has been edited by squarles (edited 03-11-2001).]
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post #3 of 13 (permalink) Old Mar 11th, 01, 03:05 PM Thread Starter
 
Join Date: Mar 2001
Location: Cypress, California
Posts: 8
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Sorry, forgot to mention that, I am running straight 30 in it right now to break it in.

Chris May
Cypress, CA
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post #4 of 13 (permalink) Old Mar 11th, 01, 04:45 PM
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Location: West Richland, Wa. USA
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Did you check the bearing clearances, replace the the plastic coupler between the distributor and the oil pump shafts, prime it before starting, replace all the oil galley plugs, and last but not least why straight 30 weight?

Air in the oil gage line is normal, hopefully you did not buy a cheap gage.
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post #5 of 13 (permalink) Old Mar 11th, 01, 05:54 PM Thread Starter
 
Join Date: Mar 2001
Location: Cypress, California
Posts: 8
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The gauge I am using is a Sunpro, I bought it at Pep-boys... It's no Autometer but it seems to be working OK. The engine was rebuilt by a company that does engine remanufacturing on a massive scale (which leads me to suspect that attention to detail may suffer). They recommended I use the straight 30 to break the motor in. I picked up the long block from them after it was rebuilt and did the final install myself (intake, exhaust, accesories, etc). I installed the oil pump also, the plastic coupler is in there and engaged. The oil pump that came in a box with the motor was new, so I didn't bother with measuring internal clearances on it (although I may have to now). I have considered installing a high-volume racing pump, but I suspect that is only going to be a temporary band-aid in regards to whatever the real problem is?
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post #6 of 13 (permalink) Old Mar 12th, 01, 05:06 AM
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Join Date: Aug 1999
Location: Ontario, Canada
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ARRRGH !!!!!!
is this not posted on the General tech also??????
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post #7 of 13 (permalink) Old Mar 12th, 01, 01:46 PM
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Location: Concord Cal. USA
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You have something really wrong. Don,t drive it untill you check it out. I think your cam idea or something about as bad it probably what is wrong. If has good oil pressure when cold and drops to almost nothing when hot there is a massive internal oil pressure bleedoff somewhere bearings galley plugs or? I once had a BB with loose lifter bores that acted like yours but not as bad. Good luck
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post #8 of 13 (permalink) Old Mar 12th, 01, 04:28 PM
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I agree with Oger, you have got a problem if it doesnt carry any more pressure than that with staight 30.I would pull it out and take it back to the builder. Did you pull a valve cover to see how well the top end was oiling?
Mike
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post #9 of 13 (permalink) Old Mar 13th, 01, 09:57 AM Thread Starter
 
Join Date: Mar 2001
Location: Cypress, California
Posts: 8
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Thank you guys so much for all the suggestions. I'm going to get underneath and pull the pan off the motor this weeked. Maybe I'll get lucky and find the sump screen and tube laying in the bottom of the pan. I'm also going to check the oil pump housing and gears for proper assembly clearances, as well as Plastigauge the main and rod bearing that I can get to. I have been told that there is no way to reach up in the block with a feeler gauge and check the cam bearing clearances. Makes sense but I just want to check with you all first and make sure that it can't be done this way? Also, is there any way I can use an oil pump priming tool with an electric drill and a pressure gauge to measure oil pressure with the engine on the stand? If I end up pulling the motor and taking it apart I would really like to make sure it has proper oil pressure before I drop it back in the car. Thanks in advance again guys!
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post #10 of 13 (permalink) Old Mar 13th, 01, 03:31 PM
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Eric
 
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Location: Kentwood, MI
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You can hook up your gauge and use a priming tool with the motor on the stand BUT the pressure will probably be lower turning the pump with a drill motor than with the engine running. I just did this with my motor on the stand just to make sure I was getting a good prime and could only get about 20 psi with my drill. Upon start up pressure was 60 psi at 1000 RPM with the engine cold. Idles at 30 psi hot with 10W30. I'm using a Melling high volume pump.

Something to look for when you've got it apart . . . check the oil galley plugs behind the timing cover. also check the spring in the oil pump to make sure the relief valve isn't sticking open. Good luck.
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post #11 of 13 (permalink) Old Mar 13th, 01, 03:47 PM
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Mark
 
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What kind of oil pump are you using? My car is very similar to yours, 50 to 60 psi at 1000 RPMs when cold. Never seems to go above 60 psi no matter what RPMS do. As the car heats up it drops down to maybe 10 to 15 psi at idle. I'm running a high volume pump in mine. High volume pumps typically have very low oil pressure at idle.

I have the stock console mounted GM mechanical gauge.

The pressure used to be lower at idle but the last time I took the console out I had to disconnect the oil line, and I found the brass ferule that crimps the plastic line into the gauge had slipped and crimped off most of the flow in and out of the gauge. As soon as I fixed that I got a 5 psi oil pressure increase at idle.

My car has been running this way since 1983. If you really have 5 psi I would probably worry but 10 psi at idle is OK. Chevys like 10 psi of oil pressure per 1000 RPM. Anything more than that is wasted HP turning the oil pump.


------------------
Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
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post #12 of 13 (permalink) Old Mar 13th, 01, 05:13 PM
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Bill
 
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Location: Waldorf Md. USA
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Chris,
before you start fooling with anything, you should call the engine manufacturer and get permission from them. Most rebuilders have a warranty, and you will certainly void it if you start pulling rod caps etc. Personally, I dont know why you even want to fool with it ??? You paid good money for the engine, call them and tell them it has low oil pressure and what are THEY going to do about it ? I know thats what my customers would be doing !

------------------
Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73
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post #13 of 13 (permalink) Old Mar 13th, 01, 05:37 PM Thread Starter
 
Join Date: Mar 2001
Location: Cypress, California
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Bill,
Unfortunately the warranty on the motor was only 6 months (thats what I get for trying to save a few bucks), and it's been about 8 months since I bought it (weekend project). So I am pretty much on my own. I did call them about it and explained my problem to them, including that I had less than 50 miles on the motor but they would have nothing to do with it unless I paid them to pull it back apart and diagnose it. I pretty much lost it with the guy at that point (which takes a lot for me!)and told him what I thought of their company. I don't think I'll be getting any assistance from them any time in the next... um.... millenium or so
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