401 wont crank

[AMX69PHATTY]

If the Oil Pressure Relief Plunger is too tight in the bore and sticks it will cause high oil pressure. Sounds like the relief isn't relieving for some reason. If the plunger is stuck it can be a bear to get out of the bore on the filter adapter.

[Mudrat]

AMX ... me? Wasn't a problem getting out. The problem was finding the spring on the other side of the shop.

My problem was a bad "new" sensor - took it back and got my $$ back when I bought the mech guages

Note to self ... put a rag over the cap when you unscrew the damned thing next time !!

[guffey24]

If the Oil Pressure Relief Plunger is too tight in the bore and sticks it will cause high oil pressure. Sounds like the relief isn't relieving for some reason. If the plunger is stuck it can be a bear to get out of the bore on the filter adapter.

The oil pressure relief plunger will not move at all, it is stuck

give me some ideas on how to get this thing out

I thought about taking a tap or a long easy out and trying to get it out, but that would be a stretch

any ideas

[guffey24]

alright guys got it unstuck and cleaned it up real good

the releif valve and the cavity it sits in

put everything back together and it did not change anything

I am thinking that the red HD spring might be the problem

I am also going to change to a mechanical oil pressure gauge

which will get rid of another thing that it could be

the sending unit

[jeepsr4ever]

I doubt your actually reading 100psi. If it was 100psi your filter would be bloated. Check to see if it had bloated on you. The plunger goes in nipple end first then the spring goes into the plunger and then the nut. Are you sure you installed the plunger correctly?

[guffey24]

yeah I installed it correctly both times

it is dripping oil out of the oil filter, and around the oil pump housing gasket, I havent looked at the filter to see if it is bloated

when I pulled the plug the spring came out and the plunger didnt, it was stuck

I got it out cleaned it up, and reinstalled it

put oil in it and the gauge went right back to 100 psi where the gauge ends

0-100 psi

[jeepsr4ever]

Red springs are rated at 70psi not 100psi

[AMX69PHATTY]

Sounds like the Relief Plunger is stuck again.
When I measured a new one from a Sealed Power Kit it was
.0001 to .0003 bigger O.D. than the stock one out of a '76 304.
Doesn't sound like much, but it don't take much.
The new one caused me same problem and ballooned a filter.

MC, would you happen to know the Plunger Dia. Spec & Tolerance ?

[jeepsr4ever]

Plungers should not be larger than .561. The hole it goes into is actually a precision bore that should be held pretty close to .5625 or 9/16". We ream the 626 and the 534 oiling plate holes out to .563 when they are being made here in house. I am suspecting you may be bypassing your filter. Whats the scoup on your oil filter adaptor?...is it new or used and what is the date code on it. Pre 1988 means oil filter bypass...1988-1991 means no oil filter bypass. Some 1987's had it either way. Maybe you forgot to put your bypass back in if was dis-assembled.

[guffey24]

the 401 came from a 78 Waggy

the oil pump housing still has some of the AMC factory paint, so it is used

the oil relief housing points downwards towards the oil pan

the oil filter angles back towards the frame rail, and the oil sending unit mounts right above the oil filter in the block with an adapter into the block

looks identical to the setup that came on the 304 that was stock

it has a little circle on the outside of the housing with 3 numbers in it

dont know the order, but the numbers are 2,7,4

it is pushing oil out of the oil pump gasket, and also dripping out of the screw that holds the spring and the plunger in place

any other ideas?

what should be my next step?