[GM man]

The bores are supposed to be .842
Not one of them is more than that

 

[GM man]

Isnt it supposed to pass some oil between the bore and lifter?

Ain't nothin wrong with them bores

 

[shovelrick]

Back to the rear cam bearing holes or groove not lining up with the cam is the only other thing it could be then correct? But like 68 said about cam and bearing both having the groove and should only be 1 or the other? Are you sure the lifters are good?

 

[MW69Chevelle]

Are the lifters new?

 

[GM man]

Back to the rear cam bearing holes or groove not lining up with the cam is the only other thing it could be then correct? But like 68 said about cam and bearing both having the groove and should only be 1 or the other? Are you sure the lifters are good?

The rear bearing has the 3 holes and the groove and the holes are aligned with the holes in the block.
They lifters look good man.
Every one of em .

 

[GM man]

Are the lifters new?

Yeah they're new. Jones was sayin he only uses 2 different brands for flat tappet. I forget what they were . Not a good thing to forget lol

 

[David Bates]

I've got a machinist/builder telling me I may have to edge-orifice the lifters. What's anyone think about that?

Edge orifice lifters will restrict oil flow up to the rockers & springs. They meter oil flow to the top end based on the lifter to bore clearance

I'm not sure what the allowed tolerances would be..I'm sure it should only be a few thousandths larger then the lifters themselves....I could see the oil leaking past the lifters on my old motor when it was running by looking through the small openings in the heads by the pushrod slots..

Actually, less than two thousandths and optimally 0.0012" minimum per Mike Lewis (aka wolfplace).

 

[David Bates]

The bores are supposed to be .842
Not one of them is more than that

And you know this based on measuring them with a dial bore gage, yes? Here are my Dart Aluminum BBC 31264644 block/Isky 3975HYRT lifter measurements - Both new.

 

[GM man]

And you know this based on measuring them with a dial bore gage, yes? Here are my Dart Aluminum BBC 31264644 block/Isky 3975HYRT lifter measurements - Both new.

Nope not dial bore calipers. Just dial calipers
Ok Lewis is sayin he likes within .0012 but does that mean anything with more slop than that is gonna equal not enough oil gettin to the top or does that mean master machinist/builder likes to see that?
I'm using these. I'm sure its not as accurate as 2 points touching the inner walls of the bore but I don't think they're gonna show me a reading that's smaller than what it is .
I don't think but idk

 

[Busted Knuckles]

As many rebuilds as I have been part of, we've never had problems with worn lifter bores, at least not enough to cause oil pressure issues. They stay bathed in oil and have little side pressure, even big blocks.
I'd double check for restrictors. If everything else is correctly aligned and the passages are clean, plenty of oil to the bottom end...pull lifter gallery plugs and make sure the oil bands on the lifters are where they should be...saw this as a problem once on a late model block with a cam that lifted the oil band completely out of the gallery. I know it's a longshot, but what the hey...

 

[David Bates]

Nope not dial bore calipers. Just dial calipers
Ok Lewis is sayin he likes within .0012" Minimum but does that mean anything with more slop than that is gonna equal not enough oil gettin to the top or does that mean master machinist/builder likes to see that?
I'm using these. I'm sure its not as accurate as 2 points touching the inner walls of the bore but I don't think they're gonna show me a reading that's smaller than what it is .
I don't think but idk

 

[shovelrick]

Have you checked to see if the oil gallery end plugs are in to deep causing a restriction?

 

[cherokeepeople]

i would also think restrictors.

 

[GM man]

Have you checked to see if the oil gallery end plugs are in to deep causing a restriction?

No but I will

 

[BillK]

Do you have a picture of the back of the block ? I am also wondering if you have restrictors. Waaay back before Moroso came out with the screw in restrictors for the back of the block guys would tap the small oil galleys that go from the cam bearing up and put a small set screw with a hole drilled in it as a restrictor. Not sure how you would figure that out without taking the whole thing apart. I don't think the oil galley plugs could go in deep enough to cause a restriction.

One thing you can do it take one of the rear lifters out and run your pre-oiler tool and see how much oil is coming into that lifter bore. Should be gushing out pretty good.

I know you are saying that you are not getting enough oil but that is somewhat subjective. I have heard some roller tip rockers that were simply noisy too.

Just thinking out loud

 

[LevonH]

Is it worth posting a good video with audio??

 

[LevonH]

5/16" pushrods with 3/8" guide plates??

 

[shovelrick]

I've only read about this from another post in this thread

 

[BillK]

I've only read about this from another post in this thread

Thats why I asked him if he had a pic of the back of the block. From looking at a few blocks I have here I think they would really have to be in there pretty far to be a problem.

 

[GM man]

Do you have a picture of the back of the block ? I am also wondering if you have restrictors. Waaay back before Moroso came out with the screw in restrictors for the back of the block guys would tap the small oil galleys that go from the cam bearing up and put a small set screw with a hole drilled in it as a restrictor. Not sure how you would figure that out without taking the whole thing apart. I don't think the oil galley plugs could go in deep enough to cause a restriction.

One thing you can do it take one of the rear lifters out and run your pre-oiler tool and see how much oil is coming into that lifter bore. Should be gushing out pretty good.

I know you are saying that you are not getting enough oil but that is somewhat subjective. I have heard some roller tip rockers that were simply noisy too.

Just thinking out loud

There's oil gettin up there . It's not makin a mess all over the inner fenders with Rocker covers off and engine running though. Sure doesn't seem like enough .
It does have roller tips. Maybe these ones are the noise makers. Idk . I've ran roller tips before with hyd. Never heard this symphony before.
It's an aftermarket Chinese pos distributor and I've got 5 old gm distributors right here.
Dimmensions are all over the map.
Maybe I just get an oem style points distributor for this motor and put a pertronix on it .