Jaykeane

Hi all.. New member.. Long post.. Long story.
I'm a marine tech, and recently had the pleasure to meet a customer with a nice, well maintained Rampage sport fishing boat equipped with a right hand rotation small block 360 Chrysler engine. By the accessories on the engine i estimate it to be from the late 1980's. Here's the story..
Last season, he noticed a lack of oil pressure while underway, his gauge was falling to near zero and the buzzer alarm was sounding and he was hearing 'clacking' up top.. His mechanic suggested an oil pump replacement.. so they hauled the boat and yanked the engine with a crane, flipped in a new pump and popped it all back together.. Same result.. low oil at idle, less under way warm.. valve train noise.. The mechanic then condemned the engine believing the main line was trash and tolerances loose... (good logic i think, but why didn't he spot check a main bearing or two while the pan was off?) The mechanic again yanked the engine and tried to sell the customer a VERY expensive fuel injected engine and new transmission to boot, to the tune of over 20K. The customer looks for another option and contacts my shop, we offer remanufactured marine engines. Since the engine is already out of the boat, the customer delivers the engine to my shop and buys the 'Reman'.. and I swap the components from the core to the reman..
Everything is in nice shape.. When I swap the main studs for the windage tray (marine engines are pretty neat!) I get a look at the main bearings.. They look new.. and are standard size.. the crank journals are gorgeous..
Anyhow.. i press on with assembly.. and prime the engine with a pressure primer (oil can under air pressure connected to the oil gallery) until oil comes out of the pushrods.. Light the engine, get the timing close and run in the camshaft at approx. 2,000 rpm on the run stand.. None of my test gauges work because the engine is equipped with SW sending units, and my test stand uses the industry standard GM values.. so i use one of those infa red guns and intend to connect the oil pressure to a mechanical gauge once I get things sorted.. The engine runs perfectly, no valve noise, good temp, the oil filter gets warm and i can see oil upstairs from under the oil cap.
I connect the mechanical gauge.. and to my horror get 15-20 psi @ idle, with a fluctuating needle and to my surprise, the pressure DROPS when i rev it.. and hear the tappets..
My first thought.. oil pump.. I have one on the shelf.. Sucks..
My second thought.. SLOW DOWN.. Look for Common Denominators.. Same complaint as before, and an oil pump didn't fix it.. The engine is equipped with a 90^ oil filter adapter that i transferred from the core to the remanufactured engine, and is the only part of the oiling system (other than the pan) that was transferred to the replacement engine.. I happen to have another one of these adapters on an old core and decide to look for a valve or something inside.. Looking inside the nipple i see some sort of valve.. and on a whim, I flip the oil filter off the engine and swap nipples, replace the same oil filter and refire the engine... 50PSI hot @ idle and bumps to 65-70 with a quick stab of the throttle ... Perfect..
I've scoured the interweb looking for information on these nipples and have come up dry.. Looking at the nipple that i removed, i see some foreign material in there that i was able to pluck out.. hard plastic.. could the plastic be part of the valve in the nipple?
Have any of you guys ever heard of this sort of thing? Is it a one in a million shot or is this common in small block mopars?

Jaykeane

Here's a shot of the filter nipple and the plastic that i yanked out of it

Coronet 500

Not common to auto oiling, threaded nipple only without extra piece of tube. The 90* adapter has a long hollow bolt drilled through sides to pass oil, and bolts it to block. Could it be some sort of a check valve to hold oil in filter if adapter turned up. Usually turned down or forward to gain header clearance in cars.

Do you know what the debris is, possibly nylon timing sprocket tooth?

Jaykeane

Nope, not a gear tooth.. Just looked at the core.. all metal, double row style, no nylon..
The filter is installed up. So normal automotive style nipples do not have a valve of any sort inside of them?
Here's a pic of the filter orientation..

Jaykeane

Damn.. just pulled that tube thingy out of the nipple and along with a simple check valve, i got LOTS more plastic debris.. The tube should be where the filtered oil re-enters the engine's oiling system.. and the chunks are way to big to get by a filter, so the pieces must have originated from either within the filter.. I got the check valve put back together and it seems to work as it should.. it would seem that the valve would keep oil in the gallery and out of the filter on shut down or during a filter change..

Coronet 500

I like the way you think, good job. I hope someone noticed, your time or $20,000.

scotts74birds

Are you familiar with the way the oiling works on Mopar SB rocker shafts? The alignment of the shafts? Just thowing it out there. I've done contracting work, and I feel your pain when a job gets away from you! Good luck buddy!