Sudden loss of oil pressure

[unklpat]

I recently acquired a 68 2000, rough suspension and steering components, 10 foot paint job, smog distributor. After spending far too much time acquiring the distributor parts from multiple vendors, we installed the correct cam, vacuum advance, springs, Pertronix unit, timed it after lowering the idle below 800 rpm. All good, go inside and wait for rain to stop, come back out and start it to what must be the "death rattle". No oil pressure at any rpm. I doubt the oil pump would fail, and have not heard that noise prior. Could there be debris plugging the pickup? Idle pressure used to read 0, cruise was above halfway on guage, fresh 5-40 200 miles ago. Any thoughts? Thanks Pat

[jrusso07]

The oil pump pick up is pretty big and has a metal mesh/screen around it - about 3” in diameter. I assume oil level is good.

Might be a blockage in the oil feed to the oil pressure meter. If you are hearing the death rattle all the time, would suspect the oil pump or blockage to the upper tensioner. It’s a very small inlet hole.

Did you find a lot crud in the oil you changed out?

You should check the evil L (upper chain guide) for chain cutting out the bottom. You can shim the upper tensioner to take up slack in the upper chain - that’s not going to fix a low oil pressure problem

[Gregs672000]

Remove the distributor mount and spin the oil pump using a drill and large, cut off flat head screw driver or the like, check for oil to the cam with the valve cover off. I DO NOT RECALL OFF THE TOP OF MY HEAD IF YOU SPIN THE PUMP CLOCKWISE OR COUNTER... I THINK COUNTER. You will need to catch the oil that will pump out of the distributor mount oil line. Oil should make it all the way to the front tensioner.

[unklpat]

Thanks, I should mention the copius amounts of red rtv on every gasket surface visible externally, seems that the same could be inside. I will take valve cover off first, and check upper tensioner shoe, and maybe put a guage on the block, but something is keeping the tensioner from getting oil. Pat

[unklpat]

Is there a way to blow out the passages to the tensioner? I am new to these engines, and there is not the internet support on "how to's". I've ordered all the appropriate gaskets, and tensioner shoes, but think it is probably simple. Hopefully. Pat

[nismou20]

Also, the stock oil pressure gauge is not that reliable at idle on these cars.

[jrusso07]

Is there a way to blow out the passages to the tensioner? I am new to these engines, and there is not the internet support on "how to's". I've ordered all the appropriate gaskets, and tensioner shoes, but think it is probably simple. Hopefully. Pat

Remove the cam cover and front inspection plate. Remove the upper tensioner by ty-wrapping the foot to the body as the foot is spring loaded and unbolting it from the head. Not sure if you can blow it out but you can check the passage. Careful not to drop parts down behind timing cover. They could really do damage. You can shim the tesioner foot out to have better contact with the chain as oil pressure builds up af start up. You may need a new paper tensioner gasket. See page 25 of U20 service manual. Get the manual from the tech wiki "manuals" on the 311s site.

Read about shimming tensioner here http://www.311s.org/pmwiki-311/pmwiki.p ... .EngineU20


If you have a lot of red rtv sealant you could have globs of it in one or more oil passages. There is a diagram of oil flow in the manual on page 43.

[unklpat]

Thanks all, I've got a tensioner shoe kit, oil pan gasket, cam cover gasket, inspection cover gasket and manifold gasket coming. Thanks Don at Rising Sun, for responding so quickly! I will let you all know in a few days what happened. Pat

[Gregs672000]

You may have to progressively work your way back to where any possible blockage exists. It may be helpful to see if someone can post the image of the oil system passages so you understand and visualize the system. I would strongly suggest you thoroughly check oil flow without the engine running as I described above. Though it is a bit of hassle, it's a lot less expensive than damaging the engine. Alternatively, you could cover the engine area with large rags and spin the motor with the starter but the ignition off so she doesn't start to see if the oil is traveling through all the cam lobes and to the tensioner foot. It may throw some oil around thus the need for the rags. Joe did a great job of describing the tensioner inspection etc. I usually stuff a rag down the front of the engine just in case I drop a nut or washer.

[C.Costine]

I was going to put my 1600 back together without getting it cleaned at the machine shop until I found a little piece of wax in the gallery behind the chain tensioner. Another forum that I visit frequently has a story now and then about damage caused by excessive use of RTV silicone.

[fj20spl311]

Is it possible he seared the pin in the bottom of the distributor that attaches the oil pump drive?

[unklpat]

Okay, valve cover off start motor briefly, oil pours out both ends of cam, with little amounts at cam lobes. tensioner spring is fine, very little wear on sprocket holder 1/16 or less. no brass plug to be found in area, what did the prior mechanic use that let go? Does anyone know the actual size of the plug in rear of cam? does the screw need to be in the front of cam? I'm sure the rest is fine, head looks great inside valve cover, other than the amount of RTV. I am trying to source one locally, seems to be 8mm or so? Thanks Pat

[david premo]

PM sent

[unklpat]

All is good now, after an interesting day following other peoples poor work. After speaking with Dave Premo, I picked up 2 1/8" npt socket head brass plugs, a letter "R" hss drill bit, a hss 1/8" npt tap, and went to work. Remove cam @ tdc, using the handy gear holder(evil L?), drill and tap both ends of cam, using grease on bit and tap, clean with brake cleaner and air, install plugs with locktite. install cam, cam gear, cam cover, and start.

[unklpat]

So we have initial startup,after plugging the cam ends. Rattle was less, but still there, no oil pressure on guage, but oil flinging all over valvetrain, surely. Bummer. What is going on? Time to check pan and pump. Drain and filter oil, nothing there. Pull pan, looks clean, wait what's that shiny round thing in the bottom of pan? It's the 1/4" plug directly above the pickup tube. Locktite back in, new gasket, 20/50 Amsoil, All good. 50 PSI cold idle, 15 PSI hot idle. I have no idea what just happened, but I was very lucky. I was driving with no cam plugs the whole time, with no loss of tensioner function. The oil pump plug happened to fall out while idling in my friend's shop. This is not as fun as driving the car. I have pictures of everything, if you guys are interested. Thanks for the ideas and help. Pat