409/409

There is a noise in my 1961 394 that I associate with lifter or valve train noise. The idle is very smooth and runs great, so I think (hope) the cam is good. Is the noise typically lifters, rocker arms or something else. I've tried 2 oil and filter changes with Lucas additives to no avail. How hard is it to put new lifters with factory air?
Thanks

redoldsman

Installing lifters is not too bad but I have no idea with the factory air. I am guessing the right side is going to be a bear. If you don't have a factory service manual, get one. It is one of the first things somebody with an old car should buy. It probably is the lifter but inspect the rockers and pushrods closely for wear.

Oldskeeper

Before you pull the engine apart I would go to a GM dealer and get a can of EOS engine oil supplement and try it. I have several 394s and one of them has a lifter noise and after I replaced the lifters I still had a noise, used EOS and the noise went away. This product was designed for the 371 and 394 engines to quiet the noise.I add a can every time I change the oil.
Steve

redoldsman

Thanks Oldskeeper. I am guessing EOS stand for Engine Oil Supplement, Do you remember the cost.

oldcutlass

Actually GM EOS was designed for engine break in. For sticking lifters I like to add a qt of Rislone (not the ZDDP supplement) or Marvel Mystery oil to my oil and run for 500 miles.

Oldskeeper

Hi Redoldsman, yes EOS is engine oil supplement, there are several types of EOS but the one I'm talking about is for 4/6 or 8 cylinder engines and added when the lifter starts to make a noise. The cost up here is around 10.00 bucks a bottle (my oldest daughter works for GM in the parts department so I just ask her to bring home a case when I'm low). I brought a few bottles to the nationals last year for the 61/64 guys.
If you can't get it where you are see if the dealer will import it from Canada.
I'll post a picture later tonight.
Steve

Oldskeeper

OK the product I use is a AC Delco EOS for 6/8 cylinder engines in a 500 ml container, part number 1 # 992869 now this might be a Canadian number that you will need to cross reference at your dealer.
ACDelco ENGINE OIL SUPPLEMENT is a multi-purpose additive concentrate designed to help eliminate lifter sticking, reduce valve train noise, reduce camshaft lobe scuffing and break in wear. (right off the back label.)
Steve

drjr56

My tap turned out to be an exhaust leak..I used a hose to listen and the valve train sounded normal.With the tap my car also runs great,but thought the noise was something under the valve covers.Turned out to be a header gasket.

rocketraider

The 394 uses rocker shafts instead of ball pivots like Chevy and 65-later Olds engines. If these shafts run dry or get sludged up they'll wear and make all sorts of clacking. Make sure your pushrods are clear so oil can get up there.

67 Cutlass Freak

This information is not correct. The 394 push rods are solid. Oil is fed to the rockers up through passages in the head, then down through the rocker shaft and spits out of the rocker itself.
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redoldsman

You are correct sir. The original pushrods are solid and the replacement ones you get from Fusick are hollow but not open on the ends. The oil comes through the second rocker shaft pedestal from the left or in other words the second from the front on the drivers side of the engine and the second from the back on the passenger side.

rocketraider

I stand corrected, and I knew better.

409/409, CutlassFreak's pictures show you how the 394 valve mechanism works and what may be causing your noise.