[MTDave]

Hello everyone. I'm running a 1971 Lincoln 460 block, And its having some Oiling Issues. Before I get to that, I'll explain about my rig, and what happened in the first place.

My rig:
F-450 Frame
Jeep Body
460-c6-205
Rockwell Axles (front steer, solid rear) on 47" LTB's

What happened:

Over time, wheeling with the rig, Lots of jumps, bumps, and general thrills while mudding. The problem that i didnt notice, Was the raise center Chunk of my Rockwell front axle has a top plate cover, which one of the bolt heads had been tapping my oil pan. one day while wheeling, I hit a bump hard enough that it punctured through the oil pan, shooting all my oil out. With full Hydro steering, I had to leave it running, but in neutral, ans my buddy quickly (2 minutes) pulled me to his shop.

Upon inspection, Piston walls were still perfect, Head components were fine. The Main+Rod bearings had gone to the copper layer (mid of the 3), however the crank+rod surfaces were still perfect. So i went ahead and changed all rod+crank bearings back to 10 over. Swapped in a High Volume Pump, and a new timing set while i was there.

When i reassembled all of it, Fired right up, ant at 75-80 PSI.

But heres my problem: At about 5 minutes of running, even at idle, It drops to 60 PSI. 10 minutes, 40 PSI, and so on. It still hasnt dropped below 5 PSI. When i hit the gas to about 2000 RPM it always perks up 20-40PSI. WHile i've been told that 5-10PSI is ok to run, Its seriously bothering me, as the Chiltons book says the block should run 60-80 PSI at 2000rpm, and around 40 for Idle.

What could be wrong that it starts at 80psi, and drops? Only possible ideas i've heard were cam bearings. Fresh Oil, break in lubes for all the new bearings, flushed everything out, kept it all clean and immaculate. So i honestly cant figure it out, and would GREATLY appreciate any advice!

 

[460Skywalker]

Sounds like you could use some 20/50 or straight 30 oil. I have only seen about a dozen 429-460 but i didnt notice the cam bearings problem like the 302s falling apart. A oil cooler might do the trick, if it come up with rpm, i dont think i worry too much, it doesnt take as much pressure as most people think if rpms are not real high.

 

[MTDave]

As of right now, its normal 10w30 Oil, full Synthetic. Oil cooler, Probably a good idea anyway. The thing is, it regularly sees 4-5k rpm, its a dedicated mudder, and i race it often. The fact that oil pressure drops over time scares me, because during races, i have to keep it moving. the Turn-off, turn-back-on solution doesn't help. So it does seem to be somewhat heat related. Perhaps the change of oil type is an excellent idea! Sorry, thinking-out-typing.

 

[Mark Miller]

When it runs for 10 minutes and drops to 40 psi at idle what is the water temperature at?

Later Mark.

 

[MTDave]

Uhm... The water temp does seem to rise a bit. If i remember correctly, when it drops to 40, its around 170, fan kicks on. 10-20 psi is about 200 degrees, and even if it holds temp it will continue to drop. Though last time round i just had to move it a bit, and the radiator sounded low on fluid.

 

[crittersf1]

Cam bearings

 

[MTDave]

Cam bearings seems to be the general concensus. While i've been told that it should be fine if it stays at 10psi or higher at idle, is there anything i can do in the meantime? thicker oil? If so what would you recommend? It does see high RPM's fairly often, and for good duration, as i race it, and sometimes get stuck/pull out stuck people. Just dont want to burn anything, or spin bearings.

 

[crittersf1]

I'd be running at least 20W50 if not straight 50W

 

[MTDave]

Well, I got to it, and took everything apart. It was indeed Cam Bearings!

So I've been doing some research and it seems the best fix is to go with Wider Cam Bearings - Anyone have an Idea where to pick up a set of these?

I was also thinking of stepping up the cam a bit while I'm at it. Which would also benefit from replacing the stock carb.

I realize im going to need to change the springs on the head for the new cam as well, I'm checking to find my Head ID code, and find the stock spring rate to see if i can find a cam within those limits, but thats doubtful.

Anyone have and suggestions for cam and Carb? And anything else i missed? Thanks

 

[bigblocktim]

I have a 71 Lincoln 460 in my truck as well, and I used the c6 from the Lincoln also. Mines an everyday driver though. I dint rebuild the engine but i took it apart to see what kind of shape it was in, and while putting it back together, I replaced the oil pump, put it all back together, and in my truck and all, I cranked it up, it sounded a lot rougher then it did before i took it apart, come to find out the oil pump shaft, had fallen out of the distributor, but I must of ran it for 5 minutes or more before I realized what was going on.
I don't know how bad I hurt the engine (not much I don't think) but my oil pressure isn't very good at all. Running 10w30, when cold maybe 50 or 60, when hot and in park maybe 5, in gear with the brake on, like at a red light or something of the sort, the gauge says 0, going down the road at 2200 RPM maybe 15 or so. I'm not sure if its harming the engine. I imagine it is, I would like to open it up and replace my bearings and what not, but as an everyday driver, there's more going then there is stopping, and fixing. I've thought of using 20w50 just haven't made it up to the parts store yet.

what all is original on your engine? and how much hp do you have?

 

[MTDave]

Ouch. I feel your pain on that!

With the exception of an Eddlebrock Performer Intake and the standalone TBI fuel system, Everything is stock - Minus teh crank being 0.010 under. Stock rating for the 71 was 365 horse, Definitley FEELS like it. Never had it tested or dyno'd

 

[bigblocktim]

yeah, it was an accident, but its part of learning.

I do believe mine is pretty much all stock, but I'm only assuming this, due to the (what looks to be) stock intake, and valve covers, although I can't say the same for the valves the valve springs and rocker arms, for some reason they look newer then they should, even though the heads look as old as the engine but the gaskets, that were around the intake, and valve covers looked new before I replaced them. I'm wanting to tear the engine down again though, this time with more time and money to work with. I would like to replace the bearings, and possibly, clean the #7 wall up if it needs it (last time it looked a little scratched, but did not have the time or money to address them all as needed) I'm hoping I will not have to replace very much at all, just bearing, maybe piston rings, timing chain. possibly valves.
not sure really, just hoping to keep parts and all pretty cheap, don't want to put more money in mine then I should. just would like it to run good, and for a long time. With hopefully not changing my gas bill, I get 16 to the gallon on a good stretch of road. I'm not sure what my hp is, I'm guessing a little more then 300, give or take. I'm running an Edelbrock peformance series carb. on it though 750 cfm, except now I'm having problems with it cranking like it suppose to. so I'm trying to figure it out right now.

oh yeah, did a compression test before I put it in my truck, most of the cylinders were around 100 to 125 I believe except for #7 it was the worse, around 75 if I remember right, I had wrote them down but, they got put in with my buddy's stuff and I haven't seen them since, but when I took the compression test, it was when I first got the engine, and the engine had not been ran for a very long time to my understanding. I only ran it for a minute or two before I did the test, and haven't ran the test since then, but before I tare it down, I will run it again. I'm curious to see how they are.