Looking for a short block

[Denison636]

Well got my 340 done and tuned in and the worse thing is happening. Oil pressure after a drive is at 16 psi at idle. Thinking of just buying a short block if I can find one.
Who makes a 340 short block that is cheap and well I can get at least a year out of it.

[burdar]

What's wrong with 16psi at hot idle?  The factory idiot light(warning light) doesn't turn on until 8psi.  Is the engine making bad noises?

[Denison636]

Motor sounds good. It runs great I am just scared of that kind of oil pressure. What is normal for a 340 with a high volume pump and spring changed out for higher pressure. And I got 50 w oil in it to.

[burdar]

That's pretty heavy oil.  More experienced engine guys need to give their    Are you running a standard or HD oil pump drive?  I think there are HD oil pump drives that have the gear pinned to the shaft.  I've read posts where the gear can spin on the shaft.  I've also seen pictures of oil pump drives that have the hex twisted off.  I think a heavy weight oil/high pressure pump, might require the beefed up shaft.

Don't just assume that you need a new short block.  Let the guys here give you some things to check out first.

[Denison636]

I got the beefed up shaft from Mopar performance.

[Denison636]

I also double checked to make sure all oil gallery plugs were in. That was fun. I dropped the oil pan and rear main off and checked that one and then the one by the distributor hole. They are there.

[jimynick]

Perhaps more to the point- what's the pressure @ 2500 rpm? While having 16psi at idle with 50 weight in it doesn't sound good, it's more about what it's got going down the road- oh and, I'd get a second gauge on it to confirm before I yanked it out. Start there and see. good luck

[burdar]

Good point. Put a known good mechanical gauge on it to verify the pressure.

[Denison636]

I got rid of my old oil gauge and put an auto meter on. At 2000 rpm I have aprox 30 psi. Maybe more. It keeps going up with rpm and is well above the 10 psi for 1000 of rpm. I am just nervous due to this is my first mopar and I don't know much about them.
I know the lt1 cameros use to only show 15 psi at idle but that was ok. Guess I am use to seeing about 30. That is what I was going for if I got a different motor. I was them going to use my heads and everything that's on it.
So truth what is good oil pressure on a 340 at idle.

[Denison636]

And it's mechanical gauge to with copper line.

[Chryco Psycho]

I would expect it to be higher also especially with 50w oil .
 the engine will live ok on what you have , possibly a different brand of oil would help , I have seen the bypass jam & drop pressure so the problem could also be a bad oil pump .

[Denison636]

Chryco I wish it was true on the oil pump. When I took the oil pan off and pulled the rear main to see if the freeze plug was in the oil gallery. It was to. I put a new mulling high volume pump and also change the spring to a high pressure one from mopar performance.
Motor at start up has 110 psi. Then after about half hour goes to 16 psi at 1400 rpm or idle.

[Denison636]

I am going to go and look at a 340 next week for sale. What is a good oil pressure at idle on these motor after oil is good and warm.

[Denison636]

And it is a 340 that is 40 over with a tranny. Can here run. This is for 2000. What you think of that price. I don't want the tranny. All I will be getting this set up for is the short block. I have to much in my heads not to use them

[Chryco Psycho]

I guess it depends on how new & the parts used to build it , I would want forged pistons , steel crank , balanced , low milage since build .
I have seen rebuildable 340s for $1000 or more & you can sell most of the parts you do not use .