Any Pontiac guys on here? Need insight.

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Bewy said:
Post #42. Pic of the oil pump drive shaft. Rough end is quite normal. If you look closely, the last 3/16" of the shaft is smooth...& slightly larger in OD compared to the rough area. The body of the Pontiac dist is a tight fit in the hole, to a depth of about 2.5"; no way it can move around to rub on anything. The gear on the dist shaft is recessed so that the smooth end of the pump drive is a tight fit inside the gear to locate & centre the drive shaft.
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I ran the oil pump this morning and it is not screaming so, that's out as a possibility. There is really no oil to speak of getting up the rockers. Pulled 2 lifters and push rods out and it will shoot a 3ft gieser of oil out of the lifter bores so, it's getting plenty of oil to the lifters. Checked the pushrods and they are clear so, we took a lifter apart. First thing we noticed is, the lifter would not collapse at all to be able to remove the clip from the top. Once we finally got it apart it has a solid disk behind the cup of the lifter so, now correct me if I'm wrong but, on an engine that oil through the pushrods this disk should have holes in it to allow oil out of the cup and up through the pushrods??

Here is a picture of the disk behind the cup.

20240217_122724.jpg
 
Should have hole in top of lifters where push rods seats into them. And oil should push through hole up through push rods to rockers

Its also a good idea to turn engine by hand running oil pump with drill make sure lifters ride at correct height in lifter bores. I had to get a cam with smaller base circle to get my hydraulic lifters to stop hemorrhaging oil out at full lift. Some times base circle too small will hemorrhage out the bottom. So need to run oil pump get someone to turn engine by hand to verify oil not gushing out between lifter and lifter bore and oil is getting to rockers.
 
340sFastback said:
Should have hole in top of lifters where push rods seats into them. And oil should push through hole up through push rods to rockers

Its also a good idea to turn engine by hand running oil pump with drill make sure lifters ride at correct height in lifter bores. I had to get a cam with smaller base circle to get my hydraulic lifters to stop hemorrhaging oil out at full lift. Some times base circle too small will hemorrhage out the bottom. So need to run oil pump get someone to turn engine by hand to verify oil not gushing out between lifter and lifter bore and oil is getting to rockers.
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I know the oil should come out the hole in the top of the lifter but, there is that disk right behind the top that seems to me to be blocking oil from coming out the top of the lifter. I feel that disk should have holes in it to allow oil out of the lifter and through the push rods. We ran the oil pump with the engine at different rotations and even turned it over with me running the drill and didn't make any difference. Still no oil getting up through the pushrods.
 
That disc acts as a flow restrictor... Oil can get around it... Top end doesn't need to be flooded with oil, it needs to be lubricated...
 
About the only thing you haven't checked is the fuel eccentric. Unless I missed that. Or you have an electric fuel pump.
 
The disc is a one way valve, let's oil in/out to shut up the lifter .
This isn't a valve or lifter issue .
 
Last edited:
1WildRT said:
That disc acts as a flow restrictor... Oil can get around it... Top end doesn't need to be flooded with oil, it needs to be lubricated...
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I do understand the purpose of the disk is to meter the amount of oil getting to the top end but, with it assembled there is no oil getting out of it which makes me think it should have hole/holes in it to meter the amount of oil allowed out of the inner chamber of the lifter as seen in the picture below. This disk has 4 small holes in it.

View attachment 1716208365

Screenshot_20240217_151730_Gallery.jpg
 
The noise you refer to, just so we agree, is the noise that starts after the engine is running, after a pause, then I hear a "scraping" sound start.
Is that it?
The delay is curious, as if vacuum, wind, or centrifugal force moves something onto a moving object/disc.
I'm thinking some creature got into the converter cover, and built a nest up in the starter drive area, jamming the starter drive in, hence gear noise. Second, dragged **** in there and ????
Converter and crank pulley are only things moving if belts off .
The other thought about the delay is vacuum to the booster, check all hoses, it's like it builds vac, then sucks,
I don't have the best speakers .
Good hunting,
 
Open

the

timing

chain

cover

and

inspect.

A worn nylon top gear on the cam will create slack in the chain that causes it to pile up on the opposite side resulting in a sound exactly like this. The bottom gear is steel so it maintains pull on one side while tension is slack on the other side due to the worn top gear.

It will also explain the delay in the sound appearing after start up as it takes a second or two for the chain to pile up once running. The piled up chain may also rub on other parts to make more sound.

It’s a simple thing to check, it’s your choice whether or not to do it.
 
Ddaddy said:
Open

the

timing

chain

cover

and

inspect.

A worn nylon top gear on the cam will create slack in the chain that causes it to pile up on the opposite side resulting in a sound exactly like this. The bottom gear is steel so it maintains pull on one side while tension is slack on the other side due to the worn top gear.

It will also explain the delay in the sound appearing after start up as it takes a second or two for the chain to pile up once running. The piled up chain may also rub on other parts to make more sound.

It’s a simple thing to check, it’s your choice whether or not to do it.
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Once I get it oiling the top end I will worry about taking off the timing cover.
 
There is no problem with the lifters...or oil supply to the top end. A tiny bit of oil is metered by the lifter [ different brands use different results, but result is the same ] with each cam rotation. Eventually it fills up the prod...bit by bit....to lube the top end.

If there was no restriction by way of the metering valve, you would have 16 oil geysers....& no oil pressure at the bearings.
 
Bewy said:
There is no problem with the lifters...or oil supply to the top end. A tiny bit of oil is metered by the lifter [ different brands use different results, but result is the same ] with each cam rotation. Eventually it fills up the prod...bit by bit....to lube the top end.

If there was no restriction by way of the metering valve, you would have 16 oil geysers....& no oil pressure at the bearings.
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I understand the metering part but it gets zero oil up there.
 
So, after doing some research and speaking with Butler's Performance it seems the lifters are probably the oiling issue. Butler's gave me a couple things to look at to confirm this. The little disk inside the lifter that I was questioning may just be the culprit. These disks are supposed to be able to allow oil past them to go up the pushrod and oil the valve train not completely block it off. They can have holes in them to accomplish this but, the ones with out holes should be stamped with a small arc to them or, have small area that is notched or, bent up to allow oil out of the inner chamber. If the valves were set too tight, over time it can flatten out the disk there for completely blocking the flow of oil out of the chamber. I have a couple more things to look at to confirm this but, I feel like this is forward progress on getting to the bottom of this.
 
Should see oil going up to rockers when running oil pump with drill. So definitely something to resolve.

Does anyone really think a rebuilt engine actually has a plastic timing chain gear? Really? All this the timing chain gear is plastic on a rebuilt engine I doubt thats the case.
 
Seams like with all the stuff that has been done to it by different folks maybe someone put a gear drive in it with the cam change. just a thought
 
roger buetow said:
Seams like with all the stuff that has been done to it by different folks maybe someone put a gear drive in it with the cam change. just a thought
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Uncle was the one who built the engine and, he says no gear drive
 
I have heard an (installed dry) front crank seal, sound like a blower drive, not a gear drive .
Re lifter, the disc opens a space when the cam lobe disappears, on the downstroke, creating the "vent".
 
First.
Post #107 is incorrect. The disc meters oil through the p'rod to the top end. What 'shuts' up the lifter is the valve at the base of the inner piston. not the disc.

Second.
The flat disc with 4 holes in it in post # 108 is used to meter oil through the prod. But how can get through the holes to get the hole in the prod socket when oil pressure is forcing the disc against the prod socket??? I am 99% sure this is how it works. With a hyd lifter, the lifter bleeds down slightly as the lifter rides over the cam lobe; this creates a gap under the prod socket & oil gets pumped through the 4 holes, into the prod socket, & into the prod.
Sol lifter, it has the lash clearance, works the same way.
 
If my explanation of oil metering is correct, & I believe it is, it would explain why no oil is getting to the top end without the engine running.
If these lifters were solids, you would get oil to the top end.
 
Bewy said:
First.
Post #107 is incorrect. The disc meters oil through the p'rod to the top end. What 'shuts' up the lifter is the valve at the base of the inner piston. not the disc.

Second.
The flat disc with 4 holes in it in post # 108 is used to meter oil through the prod. But how can get through the holes to get the hole in the prod socket when oil pressure is forcing the disc against the prod socket??? I am 99% sure this is how it works. With a hyd lifter, the lifter bleeds down slightly as the lifter rides over the cam lobe; this creates a gap under the prod socket & oil gets pumped through the 4 holes, into the prod socket, & into the prod.
Sol lifter, it has the lash clearance, works the same way.
Click to expand...
The bottom of the pushrod socket or cup or plunger( whatever you want to call it) has a raised surface on it that goes around the outside of that disk but the center has a pocket that allows the oil to get out of the inner chamber and up the push rod for the ones with the holes in it. The ones with a solid disk, the disk either can have like a notch kind of shape in the corner or the disk has like an arc to allow oil to escape out of the inner chamber of the lifter and travel up the pushrod. The size of the notch or arc of the disk meters the amount of oil that gets out. I will be messing with it soon so I will take a picture of this. This is a picture of one with a solid disk in it, it's hard to see but, if you notice the shading on the disk, it's because it has an arch in it.

Screenshot_20240217_151344_Gallery.jpg
 
Bewy said:
First.
Post #107 is incorrect. The disc meters oil through the p'rod to the top end. What 'shuts' up the lifter is the valve at the base of the inner piston. not the disc.
Click to expand...

I disagree, the same type of disc is used in many master cylinders to allow flow one way to fill the chambers , and create pedal pressure.
Regardless .
 
inertia said:
I disagree, the same type of disc is used in many master cylinders to allow flow one way to fill the chambers , and create pedal pressure.
Regardless .
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That is a completely different application. These lifters should oil all the time, the only reason for the disk is to control the amount of oil is allowed to escape the inner chamber. I believe the purpose in a master cylinder would be to act like a check valve. A lifter should never act like a check valve it has a constant flow of oil moving in one direction where as a master cylinders flow goes 2 direction which would be the proper need for a check valve type set up.
 
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