Oil Pump ?

[cudacarl]

I have a 340 mild build up. Need to change the oil pump. What is the easiest way to get the oil pan off? The engine is still in the car and it is a 'cuda. The last time i was in there was 10 years ago and the engine was out of the car so it was easy. Also i'm thinking of going with a high volume pump from sealed power or melling. The cylinders are .060 over but the rods & mains are stock. I know that High Volume pumps are for racing apps & if you cut the crank which is not my case. Would it hurt anything to use a higher volume pump or would it help? Also any rear main seal changing tips would be appreciated.

[pishta]

I was able to replace my oil pump with the motor still in the car, but just barely. Jack up the front with stands. I removed the motor mount nuts and blocked the pan with a large piece of wood. Remove the distributor cap and jack up the motor a few inches, make sure the fan clears the radiator. Wedge a 9/16 socket between each motor mount stud and the slot it goes in the K member. that should give you about an inch more room. Pull the pitman arm off and the idler off the K. Turn the wheels out and that will drop the center link down far enough to get the pan off. Drop the pan and remove the front rubber seal, slide the pan back under the trans and it should just clear. R/R the pump with fresh oil in the cavity, installation of pan is reverse of removal. Youll have to install the front seal while the pan is sitting on the K, there is not alot of room to do this. Spool mounts would be different.

[Jims451]

I did an oil pump R&R several years ago on a Challenger, and I think we were able to do it by just jacking the engine up a few inches. I don't remember if we had to lower the suspension link.
I alaways use High Volume (not to be confused with High Pressure) oil pumps. It is a matter of the clearances in the engine. On a new tight engine the High volume oil pump will be bypassing alot of oil back to the oil pan, but as the engine gets more miles on it and clearances get larger, the High volume oil pump can still meet the oil demand for the extra oil, so oil pressure is maintained.
With a stock pump it will have good pressure on a tight new engine, but then it starts getting worn, oil pressure will drop as the pump can not keep up with the extra volume demand for oil.

I don't buy the idea that a High volume oil pump will pump the oil pan dry, or pumps more oil to the heads. If the oil pressure is the same between the stock pump and a High volume pump, then the same amount of oil is being pumped "through" the engine passages. The extra oil the High volume pump is pumping is just being bypassed. The high volume pump will probbly have more suction force on the oil pickup, and if the pickup is too close the the floor of the oil pan it may cause a problem, but the stock oil pump pickup had the cover on it that should prevent the pickup from being sucked to the oil pan. If the top end of the engine is getting too much oil and the pan is running dry, you probbly have a problem with the oil drainback. I had a set of 360 heads that had so much casting flash in the oil return area that I could not get a 1/4" drill bit through it. I know, because I used a drill to open the return so I could get the die grinder in there and clean it up.

[cudacarl]

I'm not having an oiling problem right now. I had a problem flattening a cam lobe. I was thinking about dropping the pan and cleaning as much metal out as possible and then installing a new oil pump. Before this oil pressure was fine but i was thinking like you being if i'm gonna change it i might as well put a stronger one in and not have to worry about putting a bigger one in later.
I just wanted to make sure a higher volume wouldn't cause problems because i know bigger is't always better.

[dsfdelta]

CudaCarl,

I put Mopar's high-volume pump in my 360 (4286589), supposedly with 25% more volume than stock. No problems, and none of the worries about too much oil in the heads that people tried to scare me with. Just note, though, that I had to clearance-grind the pump for my stock 360 pan. Don't know if that would be the case with a 340.

[6pakman]

i just replaced all the main and rod bearings in my 340 challenger and did not have to jack up the motor. all i did was drop the centerlink and pull the pan. i also replaced the pump with a high volume pump with no problems. got great pressure[75 cold- 30 hot at 800 rpms idle]. but know im tryin to find a noise that iv had for awhile. its a hollow rapping sound. i can't quite pin point it. i only here it after i go for a ride . it doesn't do it if i start the car cold then let it warm up or just sit and idle. possible clutch chatter? its a funny noise. comes and goes after a drive, then let it idle. any comments?

[PRO]

One last tip is to never use the oil pump mounting bolts to mate the main cap and pump surfaces,always get it flush by hand or gently use a deadblow,if you use the bolts to seat it it can crack the oil pump housing and ruin the pump.As far as replacing the rear main use a piece of welding rod to drive out the top half,1st be sure you have the sealing lip installed right,think of it like this,if you have positive pressure in the crankcase it will push the seal against the crankshaft when you have it right,when reinstalling the new top half you may want to turn the crank if theres much resistance this will help roll it in.Always offset the seal halves mating surface from the main caps by 10* and dab it their mating surfaces with some "Right Stuff"sealant(NAPA) not silicone.Oh yeah be sure to lube the seals lip with oil too.If your going in that far look at some rod brgs to be sure they dont have metallic debris embedded in them,changing them now could save the whole motor. 6pkman,you may want to check your lifter preload (.010-.030)or if thats difficult add some .010 rockershaft shims(between the shaft and pedestal) and see if it quiets down,hope this helps............PRO......