Oil pressure and oiling issue?

[David Eldridge]

Hang-on
My reply was before this tidbit came out. There's nothing wrong with numbers like that. The rule of thumb is 10 psi for every 1000 rpm. So cruising at 2500 say,at 65mph, would be 25 psi minimum. If you have 37 you have lots of pressure. What you probably have is lazy lifters, or a drain-back issue, both of which have already been addressed. Or maybe your engine is just too dang hot,lol.Or just maybe somebody put some Rhodes in there while you weren't around,lol
Checking the chain can be done by rocking the crank back and forth and waiting for the chain slack to be taken up in either direction, as the top sprocket meets resistance from the valve train. I have never seen a spec for this, but I will suggest that if you have more than a half an inch of rotation, maybe 5 degrees, the chain is about to blow. A quarter inch on a 340 chain is OK, but on a nylon tipped sprocket, this is already flirting with trouble.You have to practice rocking the balancer until you get the hang of it.The first few times you will likely go to far and actually turn the cam. Start over.It helps if you do this with the balancer TDC mark near the TDC index. Then you can watch the balancer bopping back and forth.

 

[David Eldridge]

Hang-on
My reply was before this tidbit came out. There's nothing wrong with numbers like that. The rule of thumb is 10 psi for every 1000 rpm. So cruising at 2500 say,at 65mph, would be 25 psi minimum. If you have 37 you have lots of pressure. What you probably have is lazy lifters, or a drain-back issue, both of which have already been addressed. Or maybe your engine is just too dang hot,lol.Or just maybe somebody put some Rhodes in there while you weren't around,lol
Checking the chain can be done by rocking the crank back and forth and waiting for the chain slack to be taken up in either direction, as the top sprocket meets resistance from the valve train. I have never seen a spec for this, but I will suggest that if you have more than a half an inch of rotation, maybe 5 degrees, the chain is about to blow. A quarter inch on a 340 chain is OK, but on a nylon tipped sprocket, this is already flirting with trouble.You have to practice rocking the balancer until you get the hang of it.The first few times you will likely go to far and actually turn the cam. Start over.It helps if you do this with the balancer TDC mark near the TDC index. Then you can watch the balancer bopping back and forth.

Very interesting. I'll definitely check that. And I didn't know that in 70 they were using plastic sprockets. Guess it wouldn't be too bad to change. The cam shouldn't have to even come out correct?

 

[AJ/FormS]

I know they used them in 71! I had to swap one out in about 76, when it jumped on my brother in law. Very low mileage too. I'm thinking it was under 90,000miles.
If testing shows you need one;
Put the 340 chain kit on there;it may be the last kit that engine ever sees.
Cam stays in,hyup.

 

[David Eldridge]

I know they used them in 71! I had to swap one out in about 76, when it jumped on my brother in law. Very low mileage too. I'm thinking it was under 90,000miles.
If testing shows you need one;
Put the 340 chain kit on there;it may be the last kit that engine ever sees.
Cam stays in,hyup.

Been looking at replacements and it looks like they're steel now

 

[rustycowll69]

if it comes to replacement, i think he''s saying go with the 340 chain & gears, which are double roller; far, far superior to steel gears with the regular, "silent" chain.

 

[fratzog lover]

I don't know when 30 grade oil became the do all be all end all grade of oil.

When people needed that extra 3 hp.

 

[nm9stheham]

Very interesting. I'll definitely check that. And I didn't know that in 70 they were using plastic sprockets. Guess it wouldn't be too bad to change. The cam shouldn't have to even come out correct?

Your oil pressure are fair and will be better with 10W40 or more. New, you would see more at running speeds. Idle should be above 6 -7 psi or so to keep the idiot light from coming on, IIRC. And, gauges are not all that accurate, so take your gauge numbers +/- as much as 15%. The oil pump is probably worn some as well as bearings worn some too.

Yes, the cam can stay in. You have to get the front cover off, and that is tough to remove and then seal up well if the pan is not also off. So think about lifting the motor some with a jack and blocks, or some sort of support across the top of the car; be careful so that it does not fall while you have your hands and arms under there! And you can clean the pan and pickup out and swap pumps if you like while under there; they are not all that expensive. You'll need a damper puller and a tool to reinstall it.

You can check the movement of the cam while you rotate (Bop? BOP?!? What is this 'bop' stuff? LOL) the crank back and forth by looking at the spark rotor on the distributor; the distributor shaft is geared directly to the cam. As far as the crank will rock back and forth without moving the spark rotor, that is the chain slack that you have. Even 3-4 degrees slack (which will retard that cam almost that much) will make the car run doggier than new, and the more slack, the poorer it will respond at low and medium speeds. So that is another bonus to putting in a new timing chain and gear set.

As said, put in some MMO (or Seafoam) in the oil to see if that will clean up the noisy lifter check valve(s). Maybe do that now before you change oil weights. Change the filter too after that, in case it loosens up some crud. (Not that there is always a minor risk of loosening up too much sludge.) If that does not do it, there are ways to look at each lifter with the intake off while rotating things around, and see which one(s) have the weak/stuck check valves. (It gets in deeper and deeper, doesn't it?)

 

[David Eldridge]

Your oil pressure are fair and will be better with 10W40 or more. New, you would see more at running speeds. Idle should be above 6 -7 psi or so to keep the idiot light from coming on, IIRC. And, gauges are not all that accurate, so take your gauge numbers +/- as much as 15%. The oil pump is probably worn some as well as bearings worn some too.

Yes, the cam can stay in. You have to get the front cover off, and that is tough to remove and then seal up well if the pan is not also off. So think about lifting the motor some with a jack and blocks, or some sort of support across the top of the car; be careful so that it does not fall while you have your hands and arms under there! And you can clean the pan and pickup out and swap pumps if you like while under there; they are not all that expensive. You'll need a damper puller and a tool to reinstall it.

You can check the movement of the cam while you rotate (Bop? BOP?!? What is this 'bop' stuff? LOL) the crank back and forth by looking at the spark rotor on the distributor; the distributor shaft is geared directly to the cam. As far as the crank will rock back and forth without moving the spark rotor, that is the chain slack that you have. Even 3-4 degrees slack (which will retard that cam almost that much) will make the car run doggier than new, and the more slack, the poorer it will respond at low and medium speeds. So that is another bonus to putting in a new timing chain and gear set.

As said, put in some MMO (or Seafoam) in the oil to see if that will clean up the noisy lifter check valve(s). Maybe do that now before you change oil weights. Change the filter too after that, in case it loosens up some crud. (Not that there is always a minor risk of loosening up too much sludge.) If that does not do it, there are ways to look at each lifter with the intake off while rotating things around, and see which one(s) have the weak/stuck check valves. (It gets in deeper and deeper, doesn't it?)

Awesome! Thanks for all the input!