Technical No oil pressure on fresh rebuild

First flathead. Total 8BA rebuild with professional machining, quarter over bore, all tolerances to spec. Fired right up but shut it down immediately when saw no oil pressure. Checked archives and followed suggestions; dumped oil and refilled pumping it in through the back driver side oil pressure port on block (to ensure primed). Squirted oil in cylinders then cranked 10 seconds on, 20 seconds off. Repeated a number of times. Took out plug by oil pressure port and sure enough little more than a dribble coming out when cranking. Threw in another quart and half of oil just to try it and still no more than dribble. I tried to be very meticulous with the build and at this point can't believe I missed anything (???). The oil pump was new one from Speedway. Guess its time to pull the pan and pump to see if I can find the problem. Outside of making sure it is turning and the inlet tube is in the oil, not sure what else to look for. Looking for suggestions....can it be bench tested? or??.....thanks

 

Is there a oil galley plug that has been left out causing an internal bleed off?

 

I was given a fresh 300 ford that they didn't tighten the oil pump pickup zero oil pressure.

 

This happened to me on my flathead. I did all the same things you did, what I ended up doing was removing the pump and priming it in a tub of oil by hand. Dont ask me why that worked but it did. I have also packed the gears with vaseline on other oil pumps to prime them. Also make sure yiur pick up tube is mounted correctly and is close to the bottom of the pan and does not have any cracks. Good luck

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Not saying that this is your problem but it can cause the symptoms you describe. The little threaded plug above the cam on the front of the block has been forgotten before.

 

^^^^ This one. Had to laugh, (not nice, I know) but years ago in Santa Clara, there was an older man that 'built' flatheads...He had some 'signature' things he'd do, so you could recognize his engines. (one was a triangular stamp he'd imprint the block with, next to the timing cover)

A high school friend of mine brought his newly built engine to check why it had no oil pressure. Checked a few things, removed timing cover, and Voila! Plug missing.
Installed a plug, cranked it, and had 20 PSI cranking.

Years later, a guy came to my shop with the same problem: Bought a rebuilt flattie from a Flathead Specialist in Santa Clara. No oil pressure. I asked who did it. The name he mentioned had me spinning the bolts off the distributor and timing cover... No plug!
The guy was mystified at how I knew where to look. "I've seen this before," is all I told him.

 

You might want to check the clean out plugs in the crankshaft. May have been removed to clean out oil holes in the crank and never replaced.

 

Thanks for all the suggestions, pretty sure didn't leave anything out but something is sure wrong. I'll start with the pump suggestions and go from there.

 

On second thought going to start with the front timing cover and check that plug before pull oil pan. I know on one of the junk engines I had it was frozen in place and I never could get it out. May have blocked it out of my mind on this one!

 

Let us know what you find. I'm kinda in the same boat. Did my break-in and all of a sudden no pressure. Haven't looked any further as of yet, just put it on the back burner. Mine has the pump kit from Hot Rod Supply. The full flow through a filter.

 

What kind of fuel pump? If electric is the rod and bushing still in there? Could be an internal leak at the fuel pump pushrod.

 

The first time I did an oil change with full flow system I thought It would be a good idea to fill the spin on filter with oil befor installing it. WRONG! No oil pressure could be obtained. Called Mark Kirby (designer of the full flow system) and he said never fill the filter with oil. That causes a hydraulic lock in the system. I put on a new empty filter and within seconds had normal oil pressure. Live and learn.

 

Here's a rare one that happened to me but worth checking. The gear on rear of the cam shaft, which is a press on fit, came loose and would not drive the oil pump. Worth checking. I had to pull my cam and have the gear pinned.

 

had a flatty in my shop a while back .010 cam and std. bearings

 

Have to agree with flathead4d. Make sure gear fits shaft good and is not loose. Might need shaft and gear. I run 90% full flow system on mine(8BA). Runs 60psi hot and driving and 45psi at idle

 

OK, here's my update. Crank plugs are in place, threaded lug on front above cam is in place as well. The idler gear that drives the pump shaft is turning and solid so seems to be driving the pump ok. I am using the original oil filter set-up but I took that out of the circuit first thing (plugged input and drain back to pan).

I am running electric fuel pump and may very well have not left the rod and/or bushing out, but not sure. First time I've heard that one. If aacf1 or someone could expand or validate that as good possibility that would be great as I hate to pull the intake also. I thought I was ready to rock and roll several days ago.

Right now plan is to order new cam cover and pan gaskets, pack the pump with Vaseline as suggested and put back together (pending further thought on the fuel pump possibility pointed out). By the way, anyone who has packed with Vaseline....did you pack just the pump or carry it down the pick-up tube as well. I assume best to fill the tube as well.

I will update next week end to see if the problem is solved. Thanks again.

 

So you don't have a fuel pump pushrod in place?


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If you left the fuel pump pushrod out you will not be able to get proper oil pressure. A small freeze plug driven in that hole at the rear of the block under the fuel pump stand will cure that.

 

crap, that may be it. going out to pull the intake now.
js

 

That's the problem. Missed the point of blocking the hole in the block after deciding on electric fuel pump. Thanks to aafc1 for bringing it up and sidevalve and shawnsauto confirming the issue. Thought I had read and studied about everything before the build but sure missed that. Still going to pack the pump with Vaseline but glad to have found a for sure issue as well.

 

On my 41 flattie the replacement "short" pump and pickup interfered with the bottom of the pan. A little persuasion with a wooden fence post deepened the sump enough

 

Check there isn't a set screw in the horizontal drilling of the oil ways. These are fitted if the oil system had been converted to near full flow. There will be an extra port inboard of the two existing ports, that may be plugged.

Probably not applicable in this case, but it has been known to happen.

Mart.

 

Seems you've found your problem. Another way to find where the oil is going is to blow air into an oil galley an listen for a big flow.

 

Had this happen on a fresh built 454. Pulled the pan to check the oil pump and there was a blue shop rag sucked in the pick up to the pump.

 

Nonsense. If the pushrod bushing is in place, you should get good oil pressure. There is only a small hole drilled in that bushing on an 8BA. Pressure loss is small. Remember, the pushrod is a loose fit in that bushing and does not seal in any manner. You may get some spray in the lifter gallery, but that's it.

 

So you need to drain the filter whenever you shut the engine down or does it drain itself?

 

I've got little knowledge of flatmoters but got a buddy that has. He has run and raced flats since the 50's. He was having similar oiling problems and I suggested that it might be the improper installation of the cam bearings. I visited later and he said that I was right. The holes in the cam bearings were not aligned properly. Just a thought.

 

If the holes were not aligned properly, they would restrict the flow and result in high pressure at the back of the block where the pressure is measured.

 

+++ nonsense missing pump rod on 8ba will still give you pressure. Different on a 59a

T

 

Well I disavowed knowledge of flattys and now that you say that I'm thinkin that the problem was as you have described. I just wanted to emphasize the importance of proper installation of these bearings.