I have a 390 with a new standard Melling pump. The heads are stock and with all new parts and built by a pro. I have a Ford Racing oil pressure guage and have tried two sending units with the same results--very low pressure at hot idle. Now I have a squeal coming from the front of the motor--with all belts off--at hot idle. Sounds like a dry bearing to my untrained ear. Could someone please give me a list of things to try? HV pump or 6 quarts of oil or bigger oil pan or??? I am not too technical and have little available help where I live (in the mountains of Colorado0 so I sure would appreciate any help you can offer. Thanks.

 

Is it a newly rebuilt motor or old used one?
What weight oil are you running?
What is your oil pressure hot at 2000rpm?

If old used motor:
How many miles?
Any other knocks, rattles?
Does it run ok otherwise?

If newly rebuilt:
Did you break in the cam properly?
What were your bearing clearances?
Did you use oil restrictors in the head oil passage up to the rocker shafts?

I'm just full of questions. It's the only way to accurately determine a problem over the internet.

 

You might have sucked a piece of debris into the pump/pickup possibly.
The new pump might have metal debris inside it blocking flow or causing it to bind.
Check pickup to pan depth.
The pump or pickup might have come loose (bolts) don't laugh this happened to me once.
What were the issues before the new pump was installed??
As rusty asked new or old build??? etc....???

G.

 

Oil pressur spec is minimum of 35 psi at 2000 RPM, with engine at operating temp for at least 5 minutes. Idle pressure is not covered and as long as you have some you are good to go if you meet the 35 number.

 

Well, since my first post is not here...I'll try to condense it.

First I would check to see if the rocker shafts are oriented properly. The oil holes need to be AWAY from valve stem. If they are the wrong location(on the clock), it will not oil properly and make the rockers squeak. I had this issue once on a FE I bought. Took a while to figure it out.

This could also leave the oil pressure low since it's letting the oil blow by so easily. Maybe not the main cause, but could be an issue.

Pull a rocker assy off and see where the oil hole are. That would be my first check.

 

i have heard distributers make that horrible whinning sound before it is form lack of lubrication to the shaft. i think you need to use a real mechanical gauge not a electric one. use 15w40 oil and make sure the oil filter is not bad. i have seen a few on cold start up that collapse and block flow mostly fram but still cheack it out.

 

Wow! Thanks to all of you for the help. I will answer your questions as best I can.

It is a new rebuild--the crank and the 428CJ pistons and rings were not replaced as they measured OK. The heads were done by a pro shop and a new Edelbrock cam and lifters were installed. I worked with a pro so I assume the cam was installed correctly. I don't know what is meant by 'breaking in the cam correctly'--sorry.

The motor ran good before the work--(I restored the 55 F-100 it is in.)

I am using Motrocraft 10w40 oil and FL1-A filter.

There are no other sounds (knocks, squeaks or rattles) and several guys have commented how good it sounds--Sanderson headers, 3 inch exhaust with Flowmasters. It runs very good and strong.

At 2000 rpm crusing the oil pressure is 30-40. It is 50 on cold start. It just goes to almost zero at hot idle. I have used a Snap-On mechanical guage and it held better idle pressure and about the same as noted above for higher rpms.. But I still have this 'dry bearing squeak' at hot idle.

I don't know what the bearing clearances were but the guy helping me said they were fine--he has lots of experience. Neither do I know about the oil restrictors in the heads. Sorry.

Thanks for the help and I would certainly appreciate any guidance you can give me based on my answers and the additional info---and I am sorry I don't know all the answers.

 

Well, then you need to go have a talk with your "pro".

With a flat tappet cam, you need to run the motor at 1500 to 3000rpm's, slowly varying, AS SOON AS THE MOTOR FIRES for the first time. This speed needs to be maintained for 20 to 30 minutes. The lifters need to wear in to their cam lobe correctly, and to do this, they need plenty of oil. The increased speed is to splash plenty of oil up to the cam to keep the cam and lifters cooled down while the initial wear in takes place.

Your "pro" withheld some crucial, need-to-know information. I wonder if the "squeak" isn't your cam going flat. I hate to sound dramatic, but bad things can happen if the cam isn't broken in properly. When a cam goes flat, there is a LOT of metal shavings floating around...

Go have a talk with your engine builder.

 

If that's a bearing (either main or rod) squeeking, it's going to last about 2 minutes before spinning - if that. So, I don't think that's an engine bearing making that noise

The cam rounding itself out, I've done it myself, and it didn't squeek when it failed ...

What did the Snap-On gauge show for idle?

 

there is definatly an issue, you should have near 50 hot at 2500 you should have near 80 when cold, it being a bran new fresh motor and all. My new motor has 90 cold at idle, and 20 hot idle. I was running kendall 20-50, now im running mobil 1 15-50, no change in pressure. I would start by checking the rockers and valve adjustment.

 

look into the distributer as i mentioned. i had the same dry squeek on mine pulled the dizzy and rotated it with a power drill form the bottom and there was the noise again i soaked it in oil up to the manifold seal over night and it has been perfect ever since.

 

Thanks again for all of the help. Next week I have the shop owner that rebuilt the heads coming over to help figure this out. We will try what you all have suggested until we find the problem. He was very aware of the necessity to 'break in' the cam but was not around when we fired it up. As I recall we did run it at high rpm for some time--but probably not 30 minutes so that may be the problem.

I will report back what we find. Thanks again.

 

Here are the results of tonights work with my engine builder helping me--he owns the machine shop here and builds all the engines in the county--(but he is a Chevy guy!.)

I used a Mac Tools mechanical oil pressure guage and here are the results--at idle-- 50 lbs at cold ,40 lbs at 150 degrees, 30 lbs at 175, 20 lbs at 180 and 7 lbs at 210 degrees. At 2000-2500 rpms--45 lbs at 170 degrees, 40 lbs at 210 degrees. So we do not think it is an oil pressure problem.

We pulled the distributor (new Mallory) and spun it with a drill---no squeak.

We pulled the valve cover from the squeaking side (right) and everything looked fine, well oiled and clean--we ran the motor with the cover off--good oiling and no squeak coming from the rockers. The guides did not permit the valve stems to move side to side--good fit according to my builder who put the heads together.

Took off all belts and still had the hot idle squeak--so not the belts or water pump, or alternator or AC compressor.

It does not sound like a bearing wearing (to the engine builder) and as one of you mentioned, if it was a bearing--it would have spun by now--we ran the motor at least 90 minutes tonight. (It sounds more like a belt squeak than anything else--but that is not it.)

We sprayed WD-40 on the seal that the crank goes through on the front and that did not stop the squeal. (I thought it was worth a try.)

The squeal is most noticable at over 180 degrees at idle when the oil pressure is 8-30 lbs.--again it sounds like a belt.

We did not disconnect the fuel pump yet--but the sound does not seem to be coming from that side--nor from the fuel pump from the "long screwdriver listening diagnosis".

The sound is the strongest from the front right corner of the intake manifold--from the 'long screwdriver listening diagnosis'. (That is the side we removed the valve cover from and it looks fine.)

I really appreciate your help. Could you offer any other suggestions?

 

what weight oil are you using?

 

Is a pushrod rubbing on one of the holes drilled thru the intake manifold? With the engine running and valve covers off, spray some WD-40 on all the pushrods where they pass thru the intake manifold, see if the sound changes or goes away. Oil flow thru the engine goes from the oil pump to #1 main bearing, then to the cam bearings. Did you install new cam bearings? Did the shop hand fit the cam bearings to the cam so the cam rotates a little on the snug side when turned by hand with no timing chain installed?