351 ford engine

[kfx400rider03]

i have a 61 ford f100 with a 351m in it. and it has realy low oil preasure after it warms up. why would this happen? i was talking to my dad's friend who is a mechanic on the side. and he said almost every 351modidfied/cleveland/windsors he has ever dealt with had low oil preasure. he just swapped a out 351w in his 66 mustang for a 302ho because of that having low oil preasure. but my dad had a old ranchero with a 351 in it and it also had low oil preasure but never had a problem with the engine.
why do they have such low oil preasure im kinda concerned and if there is a fix i may try it deppending on how much $ needs to be spent.

[Kickstarts-suck]

Maybe he keeps getting bad 351s..

How many miles were on these engines?


What is "Low oil pressure" to him?

[CRE Performance]

Dont know about a 351W (windsor) having low oil pressure problems, these normally dont and he probably had an issue.

As far as the 351C, M, and 400M goes, they all had low oil pressure. Its a problem with the block design and the oil gallies for the lifters were too large. This doesnt cause a problem, because the lifter dont need as much oil as the crank and rods, and despite the gauge reading low, the crank and rods are getting plenty. Unless you are having lifters that are pumping down and clattering, dont worry about it.

The only real way to fix it is to tear the engine completely down, find a competent machine shop who actually KNOW about Ford small blocks and have them install an oil galley restrictor setup in it. This is the same thing that has had to be done to early Cleveland engines to make race engines out of them. But for street use, theyll live just fine.

[kfx400rider03]

kick starts suck-my 351m goes low as 5-10 when idleing and when cruising about 20 if im lucky. thats after its warmed up other wise when its cold it around 60 idleing

cre- valves and lifters do chatter at a cerian rpm when cruising down the road. it bothers me but im sure the engine will be fine its just one of those things i was hoping for a easy fix but i guess not:ermm:

[CRE Performance]

Do actually hear a lifter rattle? Like a ball peen hammer thudding on cast metal?


Or are you talking about spark knock? Such as valves rattling from low octane, lean conditions, ect??? Usually if your lifters were going to be sounding off, it would be at low RPMs when the pressure was at its lowest. If its spark knock (which is more like it) then that is an entirely different issue and can be corrected with fuel or timing.

I had a Bronco once that I drove for quite a while. It had the normal low oil pressure, and I laid another 70K miles on it before I sold it, and the new owner still has it with the same engine, no work done since I had it.

[BuB400]

I had a 1979 w/a 351M motor in it. Oil pressure was almost at 0 at all times until I put crank bearings in it. About a 8-10 hour job.

[01 250exman]

I never had low oil pressure on my 351 but it had an 8 quart oil pan and a hi output oil pump :devil:

[kfx400rider03]

cre- i do beleive it is the lifter because when im cruising down the road at low rpms is when it chatters and makes a tapping noise. but when i floor it when its doing that the tapping/chattering noise goes away untill i let off the gas again and go back to a cruising speed. the noise is just annoying when im driving sometimes.

but idk it doesnt look like i can fix it to easy so il just wait and see what happens to it :ermm: