1985 burning oil
Team Owner
Joined: Sep 2001
Posts: 62,142
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Oil Producer
Joined: Apr 2014
Posts: 9,367
Likes: 2,735
i have a SUPER HOT oil issue. it gets to 255F / 124C
i think its because the car doesnt have an oil cooler installed.
my coolant temp is perfectly normal.
when the oil is HOT like that and i come to an idle, like at a red light, oil pressure can drop to as low as 25.
i think its because the car doesnt have an oil cooler installed.
my coolant temp is perfectly normal.
when the oil is HOT like that and i come to an idle, like at a red light, oil pressure can drop to as low as 25.
Thread Starter
Drifting
Joined: Mar 2017
Posts: 1,897
Likes: 164
From: Nashville TN
2017 C4 of Year Finalist
Ok thanks guys. Just doing a sanity check. Is it true that as long as oil pressure is good, then you have enough oil in the system? My goal isn’t to run with the least oil possible, but to monitor oil pressure and if it starts to drop, then to check oil level. Or do I just need to pull the dipstick every couple days? I don’t just blindly trust anything to work on this car.
Thread Starter
Drifting
Joined: Mar 2017
Posts: 1,897
Likes: 164
From: Nashville TN
2017 C4 of Year Finalist
because the next time I will have a whole day I can devote to my car may be months away. Make no mistake-I will get this done. It's just a question of how long from now that will be. I don't want to not be able to drive my car for a few months, if all I have to do is monitor the oil level!
Burning Brakes
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Sorry, I forgot to mention that the engine should to be at least warm. Typically forged piston may have higher cylinder bore to piston skirt clearance. If there loose you can hear pistons scuffing. My service manual says cast pistons in a 85 vette. I have a 85 engine on my garage fl
I've done them the compression test cold and warm, it makes a different.
How much blow-by are you getting out the valve cover PCV breather
The rods are forged steel.
I've done them the compression test cold and warm, it makes a different.
How much blow-by are you getting out the valve cover PCV breather
The rods are forged steel.
Last edited by Mike Holmen; Jan 29, 2018 at 05:50 PM.
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Race Director
Joined: Apr 2003
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From: moraga ca
A lot of people are mentioning valve seals. The common reason oil leaks past seals is because of valveguide wear. This is something that can't be repaired in your garage. I might have missed it, but how many miles does your motor have? You might head your heads freshened up.
Racer
Joined: Jul 2017
Posts: 422
Likes: 53
From: PA
so I got some time with my car today, fixed a few issues that had been bugging me, and checked the oil. It’s at “add” after about 1k miles. I checked it with the engine cold-dumb question but that’s the right time to check oil level, right?
I swapped per spark plugs when I did the oil last. They were a little black and gunked up. Now I’m thinking that may have been oil on them.
Ive not had any issues with the car driving-the engine pulls hard and performs just like I’d expect. I get some light colored smoke from the tailpipe when I cold start her, but she starts right up without issues and doesn’t smoke after warming up a little. There’s never any black smoke and no smells that concern me. Oil pressure is 50-60 psi usually while driving (usually around 51-52).
Coolant shows no signs of oil in it.
Thoughts? What should I check/do about this?
I swapped per spark plugs when I did the oil last. They were a little black and gunked up. Now I’m thinking that may have been oil on them.
Ive not had any issues with the car driving-the engine pulls hard and performs just like I’d expect. I get some light colored smoke from the tailpipe when I cold start her, but she starts right up without issues and doesn’t smoke after warming up a little. There’s never any black smoke and no smells that concern me. Oil pressure is 50-60 psi usually while driving (usually around 51-52).
Coolant shows no signs of oil in it.
Thoughts? What should I check/do about this?
EDIT to say that the oil is pretty dark for 1k miles. It was pretty dark before the oil change though too, so it could be leftover impurities being cleaned out of the system. Just thought it worth mentioning. Definitely still looks like driveable oil, just darker than I’d expect.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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I've never researched the subject, nor have I had an 84 or 85 Corvette engine opened up, but I would be VERY surprised to find forged pistons in a 205 0r 230 HP 9.5:1 engine.
These engines have EST, pressed pins, 2 bolt mains, and are installed in 3,200 lb vehicles with no towing capacity that can't load the engine very highly for any real duration. There's no valid engineering reason to spend the money to install "forged" pistons in these engines. So I highly doubt they did.
These engines have EST, pressed pins, 2 bolt mains, and are installed in 3,200 lb vehicles with no towing capacity that can't load the engine very highly for any real duration. There's no valid engineering reason to spend the money to install "forged" pistons in these engines. So I highly doubt they did.
Factory manuals are incorrect on this subject for 84 and 85.
Thread Starter
Drifting
Joined: Mar 2017
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From: Nashville TN
2017 C4 of Year Finalist
A lot of people are mentioning valve seals. The common reason oil leaks past seals is because of valveguide wear. This is something that can't be repaired in your garage. I might have missed it, but how many miles does your motor have? You might head your heads freshened up.
Safety Car
Joined: Sep 2004
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From: Mission Viejo CA
Race Director
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From: moraga ca
Drifting
Joined: Mar 2015
Posts: 1,275
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From: Utah
Also might not hurt to install a catch can between the pcv valve and the intake.
Might see more of the missing oil vs wondering.
Valve seals are likely toast tho, my 84 sent out little smoke signals at startup @103k.
Valve seals are easy, just need an air compressor and a hose like you would use for a leak down test to keep the valves in place.
Might see more of the missing oil vs wondering.
Valve seals are likely toast tho, my 84 sent out little smoke signals at startup @103k.
Valve seals are easy, just need an air compressor and a hose like you would use for a leak down test to keep the valves in place.
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 275
From: Melbourne, Victoria, Australia
I've never researched the subject, nor have I had an 84 or 85 Corvette engine opened up, but I would be VERY surprised to find forged pistons in a 205 0r 230 HP 9.5:1 engine.
These engines have EST, pressed pins, 2 bolt mains, and are installed in 3,200 lb vehicles with no towing capacity that can't load the engine very highly for any real duration. There's no valid engineering reason to spend the money to install "forged" pistons in these engines. So I highly doubt they did.
These engines have EST, pressed pins, 2 bolt mains, and are installed in 3,200 lb vehicles with no towing capacity that can't load the engine very highly for any real duration. There's no valid engineering reason to spend the money to install "forged" pistons in these engines. So I highly doubt they did.
Went to a four bolt block scat forged 383 stroker crank and scat forged rods and forged pistons, still have the old engine in pieces.
Thread Starter
Drifting
Joined: Mar 2017
Posts: 1,897
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From: Nashville TN
2017 C4 of Year Finalist
I'm guessing here but I'm betting the EQUIPMENT was leftover, not the parts. So it was easier to keep making them the way they were already making them than to design a new process.