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I had the coolant temp at 220 ,, I would say its at least 200 on the oil ,, also this is just break in on the chassis ,,, I cant road test it ,, that's with joe gibbs 5/30 break in oil ,,
OK - that is interesting - I was running 10/30, thermostat housing temp was 205 F and the oil was 220 F.
Pan off is as Far as I got tonight - The oil pick up is right on the bottom of the pan, where I expected it to be, that is the first thing to fix. Also - 4 quarts fills the pan to the baffle which is about 3/4" under the counter weight and corresponds to almost full on the dip stick.
You stopped at a good point because the engine will drip for quite a while after removing the pan.
It is possible to change the bearings with the engine in the car if you need to.
The rods are easy. Changing the Main bearings is more of a challenge. You can roll the bearings around and out. They used to sell a T shaped tool for this. They were designed to fit in the Oil hole in the crank journal. As you rotated the crank the T tool would spin the bearing out and you could roll in a replacement.
I hope your engine is salvageable as is with little damage but as others have warned it is a crap shoot now.
Good to know - so you are sitting at 20 hot idle, any idea how hot the oil is?
In the race car the oil usually runs hotter than the water. It does a significant amount of heat transfer and cooling for the engine so seeing oil a little high temp than water is normal from my perspective.
Gauge is a VDO 270 degree readout that I verified with my compressor on a 1/8" new steel braided - essentially a brake line. This is connected directly to the oil passage back/top of the block, same as the original gauge. Wish that had been it
So far I have check rod bearings 3,4,7,8 and mains 1,2,3 and 4. To the best of my ability to tell, all are perfect - .0018 to .002 on the rods and .002 on all the mains - this is with plastigauge so +/- 10%. The surfaces on the crank are all mirrors. The bearings are all smooth and show some polishing. I'm expecting to find the same with the last 5 bearings but one doesn't know till they look, - and I'm hoping that I can re-establish the seal of the rear main after I open it up. So I'm starting to look at other places for this 12psi hot idle pressure. I'm not sure how to check the pump - as stated above the pickup was on the bottom of the pan. Someone else mentioned debris in oil pump bypass - I had a debris problem before this rebuild, so maybe I need to look there. So far I pleased with what I did not find, but still stumped as to what the issue is.
Last edited by C4toC2; 04-07-2016 at 11:02 AM.
Reason: typo
If you have a starvation Oil issue the bearings farthest from the pump are the first to fail.
Rod and Mains at the #1 location.
Pull your oil pump and look at the pressure relief valve. There is a roll pin that holds it in place. You can tap out the roll pin and pull it apart. Usually air pressure will blow the piston out for you. If the piston is stuck down the relief is wide open and you won't have hot oil pressure. The piston must slide smoothly up and down in the bore for it to work properly. Look for any scratches or marks that may have hung up your pressure relief piston.
Will do, thanks - also is the high pressure oil pump just a stronger spring in the relief valve? and then the high volume pump would actually be a bigger pump with same spring as stock?
I finally go all the rod bearings check and the only main I did not check is number 5 where the oil pump is mounted. (worried about breaking the rear main seal). Every bearing I checked is between .0017 and .002 inches. All the bearing surfaces I looked are like mirrors - and the bearing inserts all look fine. I pulled the oil pump apart, it looks OK not that I really know what to look for, and the piston moves freely in the bypass, the spring looks like it had yellow on it at one time - picture coming tomorrow. With the pin removed, the spring for the oil bypass does not extend much beyond the casing. Do I have a week spring? So nothing yet as to what would cause the low oil pressure (12 psi 10/30 weight at 220 degrees F oil temp.) So how much truth is there really to this 10 psi for 1000 RPM. People in this forum have the opinion a new engine with tight clearances should have 20 psi hot idle? What am I missing? Do most people actually run an M55HV? I believe that the oil galleys that run through the center of the engine are somewhere around 3/8 inch in dam. Based on the oil passage to the filter being not much larger than that, I would think if one of those oil galley plugs blew out behind the cam gear, the oil pressure would be worse than 12 psi (hot 220 degree oil temp idle is 850 rpm - cam is similar to L79). So I'm kinda stumped at this point and about to slap the pan back on with the pick up 3/8" higher and see what happens. Anyone out there have any other thoughts? From underneath with the pan off, the cam looks great. I was careful about the break-in and I don't think I messed anything up?
reading your post from the start,,, the 12 psi at idle when hot isn't so much an issue ,its the bouncing down to 25 when you have it at 4000,, the engine I built for my customer had a factory 8 quart pan with the trap door(fuelie motor) if you holding up @ 4000 for a period of time it could be pull all the oil out and not draining back quick enough (I have had it happen in my stocker)your pan is a 5 quart?,, as mentioned above the end play and gear side wall clearance on your pump could be out causing cavitation in the pump when the oil is hot ,,,the last thing that could be causing that is the cam bearing(but that would have to be real bad ),,end play on the pump should be .002
I'm going to take the advice and by a new pump, and a new pickup. From Summit, the pickup is $15, and I will have the old pump to practice "the welding of the pickup". I have not
tried the mig on cast iron.
I have a feeling that the spring in the bypass may be the issue, it is kind of a wimpy spring. If I use compressed air, I can cause the piston to move against the spring with 20 psi of air. I don't think 20 psi moves it far enough to uncover the bypass hole, but it does move.
I would really like to see a constant 45 lbs at 3500 rpm continuous with hot 10/40 oil. I thought the stock pump would do that. I'm going to go back and see if I can figure out what I had in my 67 camaro (that was in the '70s) - I think I put in the HV pump, I typically ran 50 psi with castor 20/50.
The pan I have is a 4 quart. 4 quarts fills it right up to the horizontal baffle which sits about 1/2 inch below the counter weight. I understand that 340 hp and 365 hp engine had the 5 quart. I have power steering which from what I have heard, will interfere with a 5 quart oil pan.
You are correct on high pressure and high volume.
One thing you can do to search for the leak it to attach an oil pig to the engine. It is just a tank with two hoses, one feeds oil to the engine and the other attaches to an air line to supply pressure. With the pan off you hook up the pig with 5 quarts of oil in and pressurize. It will pus the 5 quarts of oil into your engine at whatever pressure you choose, 35 psi is plenty. The 5 quarts will go into your engine very quick so once you apply air you need to be ready to see where your oil is dripping from. Bearings should have a steady drip. You should see no oil Pouring out. If you see a stream of oil you have a major leak and you can find the source. It very well may be a loose cam bearing or a missing oil gallery plug but this method will isolate your leak.
If your mains are rods look that good I would not pull the rear main either.
Large rebuilders used to do a sim test prior to sending the engines down the line for final assembly. It did exactly this test. Pressurize the system to look for any leaks prior to closing it up.
I would STRONGLY suggest you BRAZE the pickup to the pump body. Just take out the relief spring first so you don't remove the spring temper.
You can also buy a pickup retainer that attaches to the pump assembly bolts thru the usual sources
Doug
Good advice. I was just ready to type the same message, but you saved me a few keystrokes.
Larry
EDIT: Another good thing to remember is to prime the oil pump before installing, OR coat the gears with Vaseline so that the pump will self-prime. I learned this hard lesson at the age of 17 on my old FORD 332 engine. You only "forget" to do this once in a lifetime.
Last edited by Powershift; 04-08-2016 at 12:38 PM.
I purchased a Melling M55, but when I opened the box I found this warning pictured below. I returned it and got a Melling #10553. It is a standard volume, high pressure pump.
Manufactured with pink spring installed.To change pump to lower pressure install the supplied yellow spring. Includes intermediate shaft with steel guide. Housing and cover are CNC machined and phosphate coated.
EDIT: Another good thing to remember is to prime the oil pump before installing, OR coat the gears with Vaseline so that the pump will self-prime. I learned this hard lesson at the age of 17 on my old FORD 332 engine. You only "forget" to do this once in a lifetime.
Maybe applies to Ford, but the oil level in the pan on a Chev covers the pump gears with motor off, so it doesn't need priming.
You are correct on high pressure and high volume.
One thing you can do to search for the leak it to attach an oil pig to the engine. It is just a tank with two hoses, one feeds oil to the engine and the other attaches to an air line to supply pressure. With the pan off you hook up the pig with 5 quarts of oil in and pressurize. It will pus the 5 quarts of oil into your engine at whatever pressure you choose, 35 psi is plenty. The 5 quarts will go into your engine very quick so once you apply air you need to be ready to see where your oil is dripping from. Bearings should have a steady drip. You should see no oil Pouring out. If you see a stream of oil you have a major leak and you can find the source. It very well may be a loose cam bearing or a missing oil gallery plug but this method will isolate your leak.
If your mains are rods look that good I would not pull the rear main either.
Large rebuilders used to do a sim test prior to sending the engines down the line for final assembly. It did exactly this test. Pressurize the system to look for any leaks prior to closing it up.
That is an awesome idea!! That pretty much will tell the answer.
04-04-2016, 08:55 PM
