Hello all...

Massacre, my 86 trans am, just got a goot 350 transplant + trans...oil pressure was great then it dropped. Long story short, i took out the distributor and put a magnet down the hole. Out came the oil pump shaft. Im replacing the whole pump + shaft with hi volume pump and shaft with metal sleeve. What are the odds this will solve my problem? should the shaft just come out like that from the top of the motor??? im really praying this is the problem...any ideas???

 

It's perfectly normal to be able to remove the oil pump shaft just using a magnet. After all, it just drops onto the stub of a shaft that sticks up from the top of the oil pump. I kinda doubt it's the reason you suddenly lost oil pressure. One of the first things I would check is the 3 oil galley plugs in the front of the engine block just above the camshaft/behind timing chain. The front galley plugs are just pressed in like freeze plugs, then staked to keep them in place. It's fairly common for one to pop out. I had this happen to me on a newly rebuilt motor years ago. When that happens you'll still get some oil to the crank/rod bearings, but instead of going through the cam bearings and lifters it'll run out the hole where the plug used to be and just return to the oil pan. So if you have an oil pressure gauge hooked up back by the distributor it'll register 0. On the most recent motor I put together I tapped the 3 front galley holes and used threaded plugs, just like the factory did at the rear of the block. This may not even be your problem, but it's a good place to check if you've lost oil pressure but haven't developed a rod knock.

 

Hmm..interesting..Ill look into it and thanks for the advice...I was pretty sure there was supposed to be a sleeve that holds the chaft up to the oil pump. According to my research, If that sleeve isnt there the pump can fail. Any ideas?

 

Yeah, the stock oil pump shafts have that chintzy nylon sleeve, and they split in half and fall off quite often once the nylon gets old and brittle. 9 times outta 10 though the shaft will stay in place without the sleeve. There's really not enough room for the shaft to fall off the top of the oil pump since it goes through a machined hole in the rear main cap right where it connects to the pump. Upgrading to an ARP oil pump shaft with the pinned metal sleeve is always a better choice than the stock shaft though. I still kinda doubt that's your problem, but it's good insurance to put the upgraded shaft in there anyways.

 

Since you did not break the oil pump drive shaft I doubt the drop in oil pressure has anything to do with the pump. As previously said the three plugs at the front of the block can come loose causing major pressure loss. The other option on a recent rebuild is debris in the pan clogging the pickup.