Moparts

Help - 318 Oil Pump Exploded!

Posted By: etek

Help - 318 Oil Pump Exploded! - 08/03/09 02:31 AM

Anyone ever seen this before?
I rebuilt my Challenger's 318, following precisely the "Rebuild Your Small Block Mopar" book. Unfortunately, when the distributor/oil pump drive gear went in it went in a little tight (the brass race that gets inserted in the block). When I couldn't get it back out, but it turned with engine turning, I left it in and didn't (I know I know!) prime the engine with a drill. As I had bench tested the oil pump (checked clearances and wound it by hand, seeing oil pump) I was confident it would work.
Upon start up, it would fired and all, but would BARK back through the carb. Also, no oil pressure....shut it down and tore it down and got the cam\oil pump gear out with a little work. Went to run the pump with a drill, but at was really tight as well and chunking. Pulled the pan and pump off and found the pump TRASHED!! (see Pics) Where the pump gear engages oil pump it is shredded, as though the gear wobbled and ripped the housing out. But there's NO WAY it could have wobbled.... Any ideas??


Posted By: stumpy

Re: Help - 318 Oil Pump Exploded! - 08/03/09 03:23 AM

That looks like a classic example of not having the rod in the pump correctly and then tightening the pump down.
Posted By: MoparforLife

Re: Help - 318 Oil Pump Exploded! - 08/03/09 10:16 AM

Quote:

That looks like a classic example of not having the rod in the pump correctly and then tightening the pump down.


Posted By: NITROUSN

Re: Help - 318 Oil Pump Exploded! - 08/03/09 10:56 AM

x2
Posted By: scratchnfotraction

Re: Help - 318 Oil Pump Exploded! - 08/03/09 12:16 PM



mis-alinement on the pump

if you had the cover off the pump...did you put it back on with the right side to the pump gears?

I allways like to install the cam,iterm.shaft,with oil pan and pump off first

then after the cam is * to specs,install the oil pump,and pan

I also mark which way the rotor points on top of the inter shaft gear for a referance
Posted By: therocks

Re: Help - 318 Oil Pump Exploded! - 08/03/09 04:19 PM

Saw one just like that.Kid at work put te pump in and didnt have it seated right.Ran the bolts in with an impact and the shaft wouldnt seat after that.Installed a new pump that was seated all properly and all was well.Rocky
Posted By: etek

Re: Help - 318 Oil Pump Exploded! - 08/04/09 12:53 AM

You guys know your stuff!!
When I bought the new pump, it came with EXPLICIT instructions to make sure the drive socket is properly seated into the main cap. As you said: "Classic example" - Obviously this has happened enough to put a LARGE caution in the package inserts!!
It was easy (for me anyways ) to miss - as I recall checking the mating surfaces and seeing they where together. Although I'm not a total novice, I will sure learn from that mistake !!! Luckily it was only $80.00 ....and 8 hours re&re time. Oh well, practice makes perfect.
Thanks guys.
Posted By: CJK440

Re: Help - 318 Oil Pump Exploded! - 08/04/09 12:55 PM

You also want to check to see if one of the points of the nearby main cap bolt is not interfering with the pump socket tower, preventing it from seating properly. I've seen it more than once and rounding the offending point of the bolt head fixed it right quick.

I notice a big gouge on the flat side of the pump.

Double check that.
Posted By: etek

Re: Help - 318 Oil Pump Exploded! - 08/07/09 04:06 AM

Got a little more done on the engine today. Had to go all over town to find: a)the last oil pump drive shaft in Canada and b) an engine break in additive. Finally found the additive, made by CompCams at a specialty parts store. YES - it says $17bucks!! No one at a couple different parts stores even knew of what I wanted! Modern oils have had the Zinc removed, which is needed to protect flat tappet/non roller-rocker cam, which is all older engines. Newer engines have roller rockers, which greatly reduces this metal on metal wear. The Zinc stays put under heat and pressure and prevents cam lobe scuffing and flat spotting. Some guys are using deisel oil in their classic cars, which still has zinc and some are adding zinc. It's especially important on break in of a new or rebuilt flat tappet engine.



Before running up the pump though, I decided to repaint the intake manifold - from silver to blue, to match the engine and retain more of a stock look. So I removed the carb and other ancillary items, masked off the rest and gave 'er a few coats of Chrysler blue, plus some clear to make it show-car shiny!



Then, with a tool I made to mimick the oil pump shaft end, I ran up the pump to circulate the oil and check the pressure. I also re-reamed the pump drive shaft bushing and checked it. Now the new shaft slides in real easy like - just like a shaft should! :evil4:









Within seconds it developed nearly 80lbs, then settled down to around 60 for 30 seconds.



What a relief! Tomorrow I'll get the mill back into it's hole and get it all ready for a fire up on Saturday. What a difference a week makes. Just makes me wish I could go back to the test stand where I failed to get it running for very long. Again, a great learning experience. Soon I can say I'm just a little more like OCG - as soon as I post a video of it running!! Thanks for looking.
Posted By: moper

Re: Help - 318 Oil Pump Exploded! - 08/07/09 10:10 AM

What I dont see mentioned here is the drive bushing... that bronze/oil-lite one that sits in the block under the oil pump drive... Those are supposed to be burnushed to the correct finish size. It looks to my like the bushing may not be in square to the block, and if you had to ream it, it wasn't. the down side is, that is responsible for your ignition timing... So if you find the timing mark jumps around... now you know why.
Posted By: DaytonaTurbo

Re: Help - 318 Oil Pump Exploded! - 08/07/09 01:54 PM

Have someone hold your drill there giving it oil pressure while you rotate the crank. This helps get oil around the entire bearings and up to the rockers.
Posted By: etek

Re: Help - 318 Oil Pump Exploded! - 08/07/09 02:59 PM

Quote:

What I dont see mentioned here is the drive bushing... that bronze/oil-lite one that sits in the block under the oil pump drive... Those are supposed to be burnushed to the correct finish size. It looks to my like the bushing may not be in square to the block, and if you had to ream it, it wasn't. the down side is, that is responsible for your ignition timing... So if you find the timing mark jumps around... now you know why.




The knowledge on MOPARTS is second to none!
I guess when I said "reamed" I meant burnished. I bought the tool from e-bay. When I first got it, I didn't do it correctly and it was still a little tight, which was part of my original problem (amateur!). But since you mention it, maybe I should run it through a few more times just to be sure! Thanks.
Posted By: etek

Re: Help - 318 Oil Pump Exploded! - 08/07/09 03:00 PM

Quote:

Have someone hold your drill there giving it oil pressure while you rotate the crank. This helps get oil around the entire bearings and up to the rockers.




I will certainly do that. Thanks for the tip!!!
© 2024 Moparts Forums