Packard Forum Index » V-8 (1955-56)

Quote:

The revised cam thrust plate actually does the opposite. In the original design oil was able to squirt in a more or less continuous stream into the timing chain area to lube the chain and gears. That caused a pressure drop in the lifter gallery and was identified as another cause of occasionally noisy lifters. In the revised plate the oil was restricted to one squirt at a specific point per cam revolution. In my opinion if you have new bearings and the Olds high volume oil pump that is providing an adequate increased pressure and volume there is not a lot of reason to change the plate.

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It might be a good idea to pick up a set of oil galley cleaning brushes. Both Amazon and Autozone have them listed for around $50 for the complete set. That will allow you to make sure every oil passage is clean and clear of the paper towel fibers. I'd also check for wristpin knock or lifter issues while you have everything down.
Fingers crossed that you find nothing serious causing the knock.
John

I was gone all week and getting back into it. Pulled the passenger side head this morning. Took the rocker arm assembly apart and it all looks brand new. Oil passages are clear. Only thing I noticed that the mounting bolt at cylinder 8 just had a little oil on the shaft whereas the other 3 seemed to have a lot more.

Just like the spark plug picture in a previous post, lots of carbon on the domes of the head for cylinders 2 and 4. 6 & 8 a lot cleaner (as were the plugs) although #8 exhaust valve face show some rainbow effects of too much heat (I would guess). Wonder if that correlates with my perception of less oil on the corresponding rocker arm shaft attach bolt.

Piston faces are similar with 2 and 4 having oily residue on them. Comes off with finger and is very black. Very slight evidence of piston skirt slap too.

After I first ran the engine for a while with break in oil, I did pull plug 4 and it looked fine. Toward the end of my time running the engine, I was playing with carb mixture ratio trying to get it to run well so I'm not surprised I don't have optimal yet. I can see that contributing to carbon on plugs and dome, but why would this only occur on 2 & 4 while 6 & 8 are clean? (unless there is oil getting past rings on 2 & 4 but didn't see any bluish smoke in the exhaust, not oil consumption.

Another question: why do the head gasket holes not mirror the holes in the head and block? The head gaskets I used are the metallic ones from Max and matched the old one in it. I just bought new ones from Max with the same hole pattern. (except there are raised areas around the coolant passages for better sealing.) The current head gasket I used is shown in these photos along with the new (looks like NOS) one. The copper color on the head is Copper Coat residue.

Question Summary:
1. Why would cylinders 2 & 4 be black whereas 6 & 8 look clean with no evidence of burning oil or smoky exhaust?
2. Does #8 exhaust valve rainbow provide evidence of getting too hot?
2. Are these the right head gaskets and if so, what is the logic of the holes not matching exactly to passages in head/block?

Next steps:
1. I'm going to remove valves from this head and see what's going on there
2. Pull piston #2 and see if any evidence of problems and get a better feel for any piston slap.
3. Pull oil pump and start making sure oil path is clean throughout. (new pump inlet screen purchased)


thanks for reading and as always, I appreciate any advice you may have.

-Bob

(note: this thread started with my trying to find the source of hollow metal noise that corresponds to camshaft rotation speed. It's not the"diesel-like' noise I would attribute to piston slap, plus that would be at crank speed. Since the finding of a paper towel in my oil pan, I'm more focused now on getting the engine cleaned out and seeing if any damage was done with the reduced oil flow that must have resulted. I still had good oil pressure and noticeable oiling of rocker arm areas during all of this. )

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From what I see the gasket your holding is upside down

Raised side up.. Stamped top

Haven't heard much feedback lately so I continue to plow into this.

Riki: 'Top' is facing the head in this picture. Still don't get why the gaskets don't match the holes in the head/block. Like the big round one in the middle. Seems like that coolant should go through there and not have the gasket stop it.

Took out all the lifters and the camshaft. Seems like oil everywhere but 4 (#1 Intake, #1 Exhaust,#4 Ex, #7 In) of them show wear signs that they are not rotating. They seem to rotate easily by hand when installed. Example picture below.

Pulled the camshaft while I was at it. Some wear evident but also all surfaces coated in a light film of oil. Here are pics of the front cam bearing and the corresponding camshaft journal. The bright lights from the camera seem to make it look worse than they do by eye.

Took my heads to the shop that redid them. They looked them over and said all looked good to them. Suggested that I look for a vacuum leak esp where the intake manifold meets the heads to maybe explain why the front 4 cylinders appear to be running rich while the back 4 are not. They didnt think the standard, thin metal gasket would cover much in the way of non-uniformities across the mating surfaces. So suggested I make my own out of thicker gasket material or use Ultra Gray (instead of the Copper Coat I used).

More to come. Any thoughts would be helpful.
thx

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I would stay with metal gasket..

There is a plug in where dist goes .. Pull that.

Then you can take a long brush and clean the gallery oil supply . just remember to put another plug back in...I forgot..

I would also take the plate off the Melling pump..and make sure no paper is in gears.

And I still would pull piston..and main caps. And pull the crank.. And clean those oil holes too.

Make sure the rods are in the right direction.

Oil hole on rod facing cam.

Pulled pistons 1 & 2. Photos below. Certainly signs of wear esp since total time on the engine is probably just over an hour. But oil everywhere, maybe just not enough. I did pull brass plug adjacent to where oil pressure sensor goes and cleaned with a brush down to oil pump (and vice versa). I haven't seen anything besides oil. Ditto with the Melling pump. Took the cover off and it is very clean in there. Bought a new Melling inlet tube & screen.

While there is wear on the pistons, I am thinking it is not significant enough to do anything about it and time to put all this back together.

Maybe my noise is attributed to low oil on some part and an unclogged pump screen will address that. I am still stumped as to why the front 4 cylinders were carbon coated and the back 4 are still shiny metal.
My plan now is:
-Clean lifter bores really good (4 not rotating)
-Reinstall the 2 pistons I removed, as is.
-Reinstall heads.
-Check lifter pre-load from pusher rod
-Double the middle exhaust manifold to head gasket (both sides show leaks: wet black streaks on engine just below)
-See what changes with full oil flow.

I added a .zip file here with the audio of this pesky noise. Please let me know if you recognize it (it is at camshaft frequency)

thx

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WOW! Were the pistons new? If so that's some pretty serious and ominous scuffing.

yes, brand new Egge with 1-1.5hrs of run time. The flash from the camera really makes the wear look dramatic. Maybe that's the best way to look at it, but doesnt' look that bad with the naked eye. I took piston 1 & 2 to the machine shop today. They said it was more than expected for that run time, but not so much wear to concern them to do anything about it. Mic'd the pistons and skirts and they were right on. Said they were more worried about the fact that both the lifters for piston #1 were not rotating and to concentrate on figuring out if it was issues with the cam lobes, lifter pre-load, push rods etc causing that.

He also cautioned about drawing too many conclusions on these symptoms with the limited run time so I should fix the lifter issue, get it running and drive it to get more time/miles on it; then reassess.

I have seen zero evidence of any paper towel bits wherever I clean so I think I'm going to start putting this thing back together after I convince myself I've got clean lifter bores, good pre-load etc.

Was anyone able to open the zip file with the audio file of 'the noise'? Curious as to what others think it sounds like (metallic impingement, squeaking, etc)

thanks for reading
Bob