Okay, I have posted this before, but wanted to start a new thread since I now have more details. Here is the issue, when I drive around town and travel no faster than 50mph, everything seems OK. When I travel on the highway and do more than that, or above 55, I hear sporadic banging under the valve cover. When I remove the valve cover cap, the inside appears dry. I think the banging is from unlubricated valves. I add Marvin mystery oil and let it sit, then the banging goes away and it seems okay. it is only when I drive at high speeds. I know, I can just drive around town, and that really isn't a problem, but I would like to have this issue resolved.

Another thought: It could be a broken spring. If the motor sat for awhile, one of the springs could have picked up a spot of rust which becomes the perfect place for a spring to break & could cause random noises.

--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.

Its pretty hard to pinpoint noises while driving at 55mph.I would not discount fibre timing gear kicking up a fuss around those revs. I would use stethescope or long screwdriver on timing case and tappet cover to locate noise. Are you sure lash is adjusted on base circle of cam lobes, are followers and camshaft ok?. Pull rocker shaft completely, remove plugs, locate oil feed gallery in head and turn engine over with key. Its hard to imagine gallery is blocked unless there is damage to other parts and metal is plugging it. Chewed front cam brg can ad to gear noise. Its a case of elimination, dont stress.

Ok, what is the purpose of removing the plugs and why turn over the engine when the plugs and rocker shaft has been removed? Or better, what is it I am looking for when I do remove the plugs and turn the engine over?

Removing the plugs will allow the the motor to spin over faster. Removing the rocker arm assembly will allow you to observe the source (oil port in cylinder head) of the oil for the top end while cranking the motor over (disconnect the + side of the coil and remove the fuse for the fuel pump first). If you can't get any oil to come out the top you may have to work from the top down using solvent (carb cleaner or some such) and compressed air. I'm not sure but I think the path of oil galley goes to the oil filter area--so it may pay to remove the filter--give the crude a place to go. If you have luck with this you'll need to do an oil change or two to flush out the blockage.
It's very important that the upper end get lubricated--not only for the sake of the rocker arms but also the lifters and camshaft. As has already been stated in another's post--the oil drains back to the pan through the holes for the pushrods (which are solid-like the lifters) and drips onto the camshaft.
As for the knocking noise--another poster mentioned the timing gear--and I think that's a distinct possibility. When the fibre gear starts separating from the steel shank it can make a knock that is very loud. I see yours as multiple problems with perhaps a common cause--clogged oil passage to the rockers? -- how about clogged passage to the timing gear squirter? On the B18/20 the squirter gets oil from the same galley as the oil pressure switch. -- Dave

Ok, I have verified there is oil gushes from the oil sending unit spot. Which means, there is a serious blockage between the sending unit and on top. I have tried carb cleaner, Marven mystery oil and used a vacuum hose to try and reverse blow the blockage. Still no oil from the top.

Does anyone have any ideas on a air pressure unit where I can use higher pressure air? The only thing I can think of is to go down to some rental place and see what they have that might fit the bill. Thanks.

Hello,

It would be very unusual for anything to get in there from the oil galley side as the oil that goes to the rocker shaft has to flow between a very small opening between the camshaft bearing journal and the camshaft bearing to get to the passage that goes up to the cylinder head.

So I think that unfortunately you may have a spun camshaft bearing and if I am correct that will block off the oil coming from the oil galley to the rocker shaft.

--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Eric, so a spun camshaft bearing means what?

Hello,

If there is insufficient oil pressure to lubricate the camshaft journal for long enough, the friction can move the camshaft bearing pressed into the block and when the camshaft bearing moves enough, the hole that allows oil to pass through to the rocker shaft will become blocked.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

If the cam bearing has moved round that means major work I'm afraid. Low tech check, comments welcome, might be to remove the rocker gear to expose the oil hole and run some VERY thin oil into it. If it stays there it could be blocked off but if it continuously disappears, it's probably OK.
Do this after you've spun the motor over to see if oil is pumped up. No oil, check as above.

Hello,

Pull the valve cover with a warm engine.

Make sure the engine can not run.

Crank the engine with the starter motor, preferably with a remote starter button and look for oil oozing out from the rockers.

If there is no oil you may have a blockage in the oil passage leading into the cylinder head.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Yes, I cannot see any oil coming from the bottom. I pulled the rocker off and did not see any oil passages. I guess the oil is supposed to come from the push rods. Do you know how oil gets on top?

No.. it drains through the push rods. It gets up there through one of rocker arm supports (the ones with through which the 1/2" head bolts go). I don't remember which one, but if someone had it apart and didn't put that rocker support in the right place or orientation..

Oh hell, I forget how it can be messed up, but I'm certain it can be.

Or you might have low oil pressure, which is more common in B30s than it is in B20s... (losing all the volume through the rod or main bearings)

Were it me, do what Planetman suggested. Then look into the rocker assembly if you confirm there's no oil up there.



--
-Matt I ♥ my ♂

Brother, just so you know, I had the rocker shaft off and the only holes were the bolt holes which held the rocker shaft in place. I looked left and right for some hole for oil to come through. Here check this video out for more details:

http://www.flickr.com/photos/88748529@N08/8604941998/in/photostream

Look at the video name 1975 Volvo 164 no oil on top. If you can download it and play in window media player you will see lots of detail.

The hole you are looking for is one of the rocker stand mounting holes in the head.
The video shows the rocker stand in place - you will have to take the whole rocker
shaft with stands off. Then you will see one of the mounting holes near the center
has a 45° chamfer and about a 3/32" hole coming into the chamfer. That is the oil
passage.
I'd recommend cranking with that hole exposed and seeing if any oil shows up.
THEN I would put a real pressure gauge on the fitting where the oil pressure switch
goes and see if any pressure shows at that point.
--
George Downs Bartlesville, Oklahoma

Hello,

I took a picture of a B20 cylinder head to show you what you should see.

Notice the different shape of the casting in the head for the rocker stand location.

Can you see the oil hole coming in from the side of the bolt hole?

I am pretty sure the oil hole is under the next to last rocker stand and you should be able to see the odd shaped casting under that rocker stand.


--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Hello, you are exactly right. It was the second from the last rocker stand. I used thin cable to pry anything out. I was only able to go about 3 inches or so and then I hit the back wall before the oil passage enters from lower part of the engine. I was not able to clear anything else out beyond that point. I then used some vacuum hose and pressed one end very hard to create a seal over the stand and oil passage, and then blew into the other end of the hose. I don't know how clear it should be, but I thought I was able to blow with stiff resistance into it, which made me think I had cleared it. However, after reassembly, still nothing comes from the top.

Does anyone have any ideas on how to clear the oil passage?

And for further clarification...

Should that rocker stand not have a hole in it that goes up to the rocker pivot assembly? Or is the bolt at that stand machined? It's been a long time since I've been in there, and I don't remember how it goes..

--
-Matt I ♥ my ♂

Hello,

All the rocker stands are the same and all the rocker stand bolts are the same.

The oil flows past the rocker stand bolt up through the rocker stand and into the rocker shaft.

--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Thank you for the photograph. I will give it another look over tomorrow.