I have a 127,000 miles on my truck and the oil pressure starts to sink after about 20 minutes of run time the oil pressure sinks and will only stay up if the rpms are up. I put a mechanical pump on and it did the same thing. I figure my cam bearings have worn out causing low oil pressure.
What I plan to do is dear the motor down to the bare block and have new cam bearings installed and the cylinders bored .010 over if necessary. Any other machine work I should have done? I plan to use the comp cams 31-255-5 with new comp lifters, chrome molly push rods, timing chain set, and roller lifters with new springs as well. I'm also ordering the master engine rebuild kit from summit by sealed power with the 10.13-1 compression pistons. I plan to also replace coil,cap/rotor/wires with MSD components, and also use a set of flow tech long tube headers and the K&N intake kit. Anyone have any idea how much power I could expect to make? Also wandering if anyone has any suggestions they would like to add?
Thanks,
Capt. J

 

Cam bearings seldom wear out…

If you have that engine down that far have it bored and honed (likely will need more than .010 oversize… buy the pistons AFTER the block has been bored). Ditch the 'moly' pushrods… overkill and no need for them.

The crank should be polished. Rebuild the rods… you only need stock bolts...

10.1-1 will mean you'll have to run 93 octane minimum… keep it to 9.5.

The K&N kit will look cool but do nothing.

Talk to a few different cam grinders… tell them you want a FORD grind not a generic cam as most are ground for Chevys. Comp would be my last choice.

MSD isn't needed but if that $$$ is burning a hole in your pocket go for it.

 

Take your engine to a machine shop and have them tell you what it needs to return to spec.. then buy the appropriate parts.

10:1 compression is too high for a truck motor keep it closer to 9:1.

You can't use roller lifters with a flat tappet cam, you should be able to use the factory roller cam assembly in your block however and then install an aftermarket roller cam if you like, but it's got to have 114LSA and no more than 210deg duration at 0.050" lift. The comp 35-512-8 is one that will work.

This combo should make 260hp or so and upwards of 350 torque, or in other words it'll be a lot more potent than stock.

 

UPDATE!!!!
So I talked to the machine shop in Joplin MO today and they said i could get new cam bearings, cylinder hone, and valve jobs for $175 which is a hell of a good deal. I will bore it over .030 if I have to. I really want to go with 10.25:1 instead of stock compression because i want to get all that i can out of the motor. My 90 was not a roller cam motor so I'm going to stick to the flat tappet. I now I'll have to run higher octane fuel but the truck isn't a dialer driver so it shouldn't be to much of a problem. The cam i"m getting as mentioned in the original post is a comp cams computer controlled cam. Talked to the rep on the phone and he said thats the most aggressive i could go without messing up the computer. Should the factory computer be okay? How noticeable will the performance of the motor be compared to stock BTW(its a 5spd). I am going to run it with straight long tubes, hope it will sound good lol

 

My '90 302 block was roller cam ready. You cam get the spider and dog bones and steer away from the flat tappet cam, unless your dead set on flat tappet.

 

I kind of am I guess. I know I still have to put the special additives in the oil. Will my 5spd be able to handle the new power?

 

If I had to do all over again, I would have gone roller, and not looked back. Given no break-in needed and no need to run expensive ZDDP additive or $5-6 quart if oil, I wouldn't look back....not to mention, freeing up a few more ponies since you won't have the added friction of flat metal lifter pressing against a flat metal lobe.....but..............

 

how is this thing going to sound with open headers? I do realize ill have to weld in an o2 sensor bung.

 

is the EGR worth keeping?

 

Where was this? I'm in Carthage. Maybe we should meet up someday.

 

I'm in Pittsburg I go to pitt state

 

Keep it in the 9's even if it's the high 9's it'll be less detonation prone.

Your 90' block is roller ready so the factory spider from a Mustang for example is a bolt-in, have a look around to see if you can buy an assembly from a mustang guy that is upgrading, you might even score the whole works with the stock HO cam which is also an SD friendly grind and a healthy upgrade from your stock truck cam.


VERY noticable.

It'll be loud! Are you gonna put any kind of muffler on it?

 

quick update!! I have kept the old motor in the truck for the time being. I recently purchased a long block out of a 90 mustang that was a factory roller. And I also recently picked up a set of gt40 heads out of a 93 cobra. They have the crane 1.7 roller rockers and double springs with a mild port job. After I take the motor to the machine shop and get it back into spec what should i expect out of the motor. New 10.13 speed pro forged pistons stock rods polished crank. Comp 35-512-8 Cam on SD with new roller lifters rods etc. All factory ignition components replaced with MSD. Do I need to get the stock f150 intake port matched to the new gt40 heads since they were ported. Also I understand i need to change the firing order any suggestion on that? Is all of this a good combination for my motor?

 

Have you considered going to a 351 instead of using the 302?

 

I already bought the 302 roller motor and the gt40 heads. Its kind of a challenge for me to see how much I can squeeze out of the old 302.