i have a fully restored 76 GMC . the motor was rebuilt at the start of the restoration. The rebuilder died during the process and his son attempted to finish the job but failed miserably. New Fuel injection, headers, intake manifold, single belt accessories and painted. It is beautiful but now it is blowing oil out the exhaust pipe at about a quart every 200 miles. Did compression check and 7 cylinders are about 140 and one is about 120. i am ready to buy a first class crate motor and replace it. Money is really not an issue. i have a $150k in it now. Can anyone recommend a motor source and more importantly someone to install. I am in Dallas Texas. please help.
Need motor and installer.
- Thread starter Dale Sellers
- Start date
If you let the motor get down to the "add" mark on the dipstick, does it continue to consume? It's common for these engines to consume way more oil when they're at the full mark (or over-full, rather).
I don't recall what the nominal compression is off the top of my head, and the compression differential isn't ideal, but I've seen worse engines perform reasonably well for quite a spell.
Many people have had luck getting engines from S&J in WA--a few people have not had luck. I can't help with a Dallas recommendation, though I'm sure someone else can.
I have a Cadillac 500 in my 74 Canyonlands that S&J rebuilt, it doing great.
Check your valve covers. I have heard that pretty fancy and or car valve covers on Olds 455/403 motorhome engines will throw a lot of oil.
20 lbs between cylinder compression isn't too bad. The FAA allows 20% loss on a differential compression test. 80 lbs in and no less then 64 out on piston airplane engines.
Definitely check your valve covers. If they aren't stock with intact baffles, get some that are. This is a high performance engine run at high loads, it needs really good PCV baffles or it WILL consume oil.
And Yes, Also check your oil levels. Dipsticks are frequently very wrong and too much oil will be consumed
And Yes, Also check your oil levels. Dipsticks are frequently very wrong and too much oil will be consumed
Blowing oil out the exhaust manifold, ... how is that even possible?
Is it smoking out the tailpipe?
Or is it leaking out on the pavement?
To check your dipstick, do an oil/filter change and then put in 5.5 quarts. That should read full.
Non-stock, non-baffled valve covers can supposedly lead to oil consumption.
Is it burning it or leaking it?
I think you just need to find a good local ole-school mechanic to wrench on it and fix the oil leak, wherever it is.
Is it smoking out the tailpipe?
Or is it leaking out on the pavement?
To check your dipstick, do an oil/filter change and then put in 5.5 quarts. That should read full.
Non-stock, non-baffled valve covers can supposedly lead to oil consumption.
Is it burning it or leaking it?
I think you just need to find a good local ole-school mechanic to wrench on it and fix the oil leak, wherever it is.
Ring problems will blow oil out the tailpipe.
Have someone do a leak-down test on it. That should help clarify what is going on and whether that cylinder with the slightly lower compression has a problem.
The other way oil can get into the cylinder is through the valve guides. I'd be pretty surprised if that were the problem.
Have someone do a leak-down test on it. That should help clarify what is going on and whether that cylinder with the slightly lower compression has a problem.
The other way oil can get into the cylinder is through the valve guides. I'd be pretty surprised if that were the problem.
Hi Dale,
This is Robert, previously of the C
-
p. Besides your engine, All of them from that batch have failed! One customer had his rebuilt by his re-builder and is now happy with the performance. IDK where his re-builder is located, but I could ask for you if you wish. If all else fails we can do the motor swap here @ Alex Sirum GMC. Hope that helps!!
This is Robert, previously of the C
-p. Besides your engine, All of them from that batch have failed! One customer had his rebuilt by his re-builder and is now happy with the performance. IDK where his re-builder is located, but I could ask for you if you wish. If all else fails we can do the motor swap here @ Alex Sirum GMC. Hope that helps!!
Necro-posting, but it sounds like there is a story there....Hi Dale,
This is Robert, previously of the C
Ya think? Of course there is a story! We ALL live themNecro-posting, but it sounds like there is a story there....
.
This is my Rocket 455 that was pulled to install the COOP 455 that I bought at the COOP's end of business auction.
The new FiTech fuel injection Rocket COOP 455.
The old engine was running very well with its carb when it was pulled. It wasn't burning oil. I still have the carb and air filter.
Cliff Golby pulled this running 455 and installed the new COOP motor.
Cliff mocked up the altered March Racing system with two new Balmar alternators (12v, 160a + 48v. 60 a) and no engine driven air conditioning compressor. The new compressor is 12vdc. There is also a brand new water pump and power steering pump.
The pulled motor is in Palmetto, FL.
I need to sell it to someone who will use it and save it from the dump.
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