1951 Chevy 235 No oil going to the rocker assembly

Hey all. Ok, I have scowered the forums and not been able to find the info I am looking for. I have a 235 that I pulled and completely went through last winter. The motor was all original. Reconditioned everything, cleaned all components, replaced what was needed and reasembled. The car was running great. I was driving her to work one day and I started hearing some valve train noise, turned around and took her home. After looking into it I found that there is no oil getting to the rocker arm ***embly and I suspect there is no oil getting to the hydraulic lifters. Since it ran flawlessly for a while I do not suspect the "mystery" head bolt. The rockers are fed by a steel line that goes up through the side behind the cover where the lifters are and then up through a hole and then connects to the rail. I started it up and checked oil pressure. I have great oil pressure. 20 psi at 2000 rpm. I have removed the rockers and checked all the p***ages on the rail, all clean. I cranked the engine and there is NO oil flowing up through this tube. ANY suggestions on what to possibly look for would be extremely helpful before I lose the rest of the hair that I have. Thanks in advance.

 

Dumb question, but are you sure your dizzy is in all the way? The dizzy shaft drives the oil pump. It's easy to not get it fully down if you've taken it out or replaced it and have zero oil flow from the shaft not engaging the oil pump.

 

What he said. Pull the distributor and identify the slot at the bottom of the hole and manually spin it and watch for oil up top. An old pushrod with the socket end cut off and the other end ground flat like a screwdriver blade in a power drill will let you test the oiling system.

 

Yes. I have pulled the distributor and checked the pump/pressure with the long screwdriver and a drill. I am getting good oil pressure throughout the motor, just not to the rocker feed tube or the lifter bores.

 

Oil flow is divided by a valve on the side of the block just above the pan rail on the manifold side. Dis***emble that valve and be sure it is together right, gasket in the right way, etc., and I think you'll find the problem.

 

What R Pope said too, and have a look at that line where it turns a corner to go through the block in case the line is kinked.

 

Alright, I will have a look at that tonight after I get out of work. I will keep my fingers crossed. Thanks.

 

Be sure to post up what you find. And good luck!

 

Did you fix the pressure prob. I have the same problem in a 55 Belaire

 

I know this is a really old post, but I still have not found the issue. Life became an issue and I have not had time to look at it until recently. I am out of ideas. I think my issue is larger since I am not getting pressure to the hydraulic lifters either. Need to take the head off, pull the pan, and flush the whole oiling system...Thats the only idea I have. GRRR!!!

 

Your "mystery bolt" has a very small oil p***age in it. I'd pull it and make sure it not plugged up. It would take 5 minutes to check. Might be worth a look.

 

yup, the line might be kinked. That was happening on mine too. It also had a little crack in the line too.. I had to braze it

 

If the line is not new, theres a very good chance it is blocked internally. Verify 100% there is no blockage. If its original, consider replacing.

 

yup mine was blocked on my 57

 

When I was younger and these cars were just old used cars. The simple fix was an external oil line from a tapped hole near the bottom of the block up to another plug in the side of the head. 1/4 inch copper tubing and flare fittings to the pipe threads. A lot of old Chevy's had that band-aid.

 

I ran an external line on mine and a high volume oil pump.

 

external line is a real common fix and took me a long time to figure out this wasn't factory. took the advice of somebody i figured was GM experienced and removed the external line (it was leaking) on a 235 i had and if i hadn't been changing the valve cover gasket i would have been changing the entire motor.

 

Well...I got down and dirty on the engine this weekend. I have no mystery bolt. I have checked and double checked this out. Each hole for the head bolts are solid, there is no oil galley going through any of the head bolt holes. I would run an external line to the rockers and remedy that way, but I also have no oil going to the lifters. This last weekend I pulled the pan, the rocker ***y, and the lifters. I also pulled the junky "oil filter" off of the drivers side of the block. Me and a friend started to trace the oil paths. This is what we came up with. The oil goes from the pump, into a galley on the block. From there it goes to all of the main bearings. Once through the mains, it then goes into each corresponding cam bearings. From the rear cam bearing the oil pressurizes all of the lifters and then from a br*** fitting and a steel line, goes up to the rocker ***y. So now that we know this, we pulled out the ol' compressor and started to put some air in some holes to see what happens. What we found is that all the p***ages are clear, all look great, and all had good air flowing through them, but the issue is that we are getting a very faint "breeze" coming out of the hole of the lifters and the rocker feed. The majority of the air is escaping from what looks like a machined hole in the block where the rear cam bearing is pressed in. This hole makes absolutely no sense to me. I will supply a few pictures I took and see what you guys think. Am I just being dumb or would just welding that hole up give me straight pressure to the lifters and rockers?? Thanks in advance everyone!

 

Sorry, let me break down each picture for you guys....

The first is a picture of where the br*** fitting threads into the block, this is where the steel line attaches and goes up to the rockers, also from this same place is where the pressure should be feeding the lifters

Second picture is the oil distributor and where I had the oil filter hooked up...Not too sure on how the distributor works so if someone has some insight on that, it would be greatly appreciated

Third is that damn machined hole. This is the hole where a majority of our air pressure was dumping out of... when looking through the hole you can barely see the back side of the cam and then just a useless pocket. Oh yeah, and while I had this apart we rolled the motor over, neither the cam bearing or the rear main bearing are spinning, both are still solid and look to be performing properly.

And last is a picture of the lifter holes....not really sure why I attached that, must be just PURE FRUSTRATION!!!

 

It's been a long time since i've been inside a 235. I think the hole in the first picture should have a fitting in it and an INTERNAL oil line from there to the center of the valve lifter cavity at the the top to feed the oil up to the center of the rocker shaft.

This was the line that would get plugged up and the simple fix was the external line.

This would retain oil pressure to the lifter gallery, too. Cause now you just got a big hole there to bleed off all the oil.

The bottom hole I guess should be there.
Edit. I think that bleeds off what gets thru the bearing. without that it would build pressure behind the cam and pop out the cover plug. Maybe?

 

Yeah. There was a fitting there, and that is where the steel line hooked up to send oil to the rockers. I just had it all removed to inspect everything. That would make sense about the hole on the bottom in the cam bearing. It just baffles me why most of my pressure is getting through to this hole.

 

You might want to ask this question over on the stovebolt website, there are a lot of Chevy 6 experts over there. Is that hole threaded? Maybe a plug is supposed to be in there?

 

Are you sure you are dealing with a 235? The second photo shows an oil distribution plate that I have only seen on 216 motors. I have been wrong before (many, many times) but even the shot that shows a bit of the head it looks more like a 216 head. I will admit I have not had much expience with early 235s 40-53 but I am a little su****ious you may be dealing with a different motor than you think.

 

The early 235s looked like 216s and were also splash oilers,they came in cars that were ordered with powerglides and big trucks too. In 53 or 54 they became pressurized.

 

It's a 50-52 (only) 235 based on this picture ID page:
http://pugetsoundvintagechevrolet.org/Programs/6 cylinder engines with photos.pdf

 

I'm very curious to see the cause of this problem

 

Thanks for the correction/info re early 235s, I was thrown off by the reference to hydraulic lifters? I thought they came out in 53 in cars with automatic trans which would be the later block without the plate, right? I am also very interested in the outcome or solution to this one.

 

Hydraulic lifters came out in 1950 in the Powerglide 235. I don't know all the answers but I do know you can create this problem by using valve lifters intended for later models. Just a guess.

 

Well fellas, still havent found anything that throws a red flag. I guess I am just going to double check all of the ports and galleys and pump and slowly re***emble. While re***embling I am going to eliminate the ****py "oil filter" and also take out the head bolt that goes in the mystery position and drill it out, although I know that is not the problem, I am going to eliminate that option. As far as that oil distributor goes, can anyone give me a run down on how that works, the manual doesnt really give a whole lot of description. Thanks again guys, I will keep ya posted.

 

Alright. I will definitely look into the lifters in this thing. It probably wouldnt hurt to throw some new ones in it anyway. Thanks!