I recently rebuilt my 455 and when I started it up, I found I was getting zero oil pressure. Shut it down to investigate, but not sure why. Priming the oil pump sends oil through the filter but not getting anything up higher. I had the crank turned and new bearings installed at a machine shop. Any thoughts before I pull it back out? Thanks.

 

There's a pipe plug at the back of one of the oil galleries (I want to say RH side, but I don't remember for sure at the moment). This plug is down in a hole and is covered by another pipe plug at the bellhousing face of the block. The internal plug has a small hole that provides an oil drip to lube the distributor gear. If you forget to install this inner plug, all the oil from the pump just dumps on the distributor gear and runs back into the pan.

 

I checked the 1966 service manual, and got this text:And there is a picture (attached).

Note that this is applicable to the 425ci engine, so the normal 425 vs. 455 caveats apply.

 

Thanks guys, that makes a lot of sense. My first rebuild and I guess I just missed it. Never saw anything about it in the books I had. Unfortunately it sounds like I still have to pull the motor again, but at least now I have an idea of where to focus. Thanks again!

 

Memory is the second thing to go, and I can't remember the first...

Thanks for the correction.

 

There are also 2 plugs behind timing chain cover. One with a pinhole for timing chain oiling and the other just a plug. If these were left out you would not necessarily have to pull the engine only the timing chain....with the rear one I think you could do the job by removing the trans.

 

If the engine has been run without oil pressure, it's coming out.

 

Yeah, it's coming out. I want to check my mains. I am hoping that because I had oil to the filter, that the mains were getting oil. I will check the rear plugs first and then check behind the timing chain cover if needed. Got everything disconected this morning and will hopefully have it out tomorrow. Will let ya'll know what I find. Thanks again!

 

Yes the engine should come out and all apart to be sure...I had a similar situation with a 394 that was supposed to be rebuilt but never started. It was in the 59 I bought...I started it and had no oil to the top of the engine. Ran like crap for a few minutes. Checked oil pressure and had about 4psi...just enough to keep the dash light off. Found the front 2 oil galley plugs missing...the rear one was there....Am not pulling it though as all seems well now....will take my chances and when/if it starts knocking it will be time to pull it....

 

When priming an engine it shows oil pressure on the gauge. Is there a reason it wouldn't have pressure after starting but does when priming?

Allan

 

Hey guys, I wanted to say thanks for the advice and for the tech tips. I found the culprit, or culprits as it were. The two galley plugs in the front did not get put back in when it came back from the machine shop. Since I didn't pull them, it didn't even dawn on me that there was something missing when I put the cam, timing chain and cover on. Rookie mistake. Good news is that I checked the bearings and they were good, I put the plugs in and put the motor back in and it's running fine now with good oil pressure. A few more pieces parts to hook up and it should be back on the street. Thanks again!

 

great thanks for that info--pulled the freeze pug-like cup yesterday and couldn`t see anything --guess a torch should solve this

 

What I normal due after a rebuild, is while primimg the motor I hook up a spare oil pressure gauge so I can keep an eye on it while primimg. I also look down the dist hole to make sure the dist oiler is squirting. I do this on the stand before I install it. Been there done that. JKaz

 

You need to prime it until oil comes out of all the pushrods.

And, rotate the crank 90 degrees every 30 seconds of priming.

DO NOT start the engine until this happens.

 

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