Urgent help needed for AMC 401 Motor

[Bouncy]

In the barn now.

Motor fires up. Its a new rebuild. New timing chain cover, new oil pump gears.

NO OIL PRESSURE.

We have tried priming the motor for about 15 minutes using the starter...Can't get oil pressure.

Finally we fired up the motor for 10 seconds. There was assembly lube on the bearings. Otherwise I wouldn't have tried it.

Still no pressure at all.

ANY IDEAS on getting this primed??

Thanks.

 

[Root Moose]

Is this helpful?

http://www.pirate4x4.com/forum/showthread.php?t=272152

 

[5-90]

In the barn now.

Motor fires up. Its a new rebuild. New timing chain cover, new oil pump gears.

NO OIL PRESSURE.

We have tried priming the motor for about 15 minutes using the starter...Can't get oil pressure.

Finally we fired up the motor for 10 seconds. There was assembly lube on the bearings. Otherwise I wouldn't have tried it.

Still no pressure at all.

ANY IDEAS on getting this primed??

Thanks.

Remove oil pump.

Remove oil pump cover.

Pack area thus revealed with light chassis grease or petroleum jelly (Vaseline.)

Replace oil pump cover.

Replace oil pump.

Remove distributor.

Remove oil pressure sensor, attach mechanical oil pressure gage.

Using a "priming rod" and a drill motor, run the oil pump until you develop oil pressure. Maintain for one full minute after you develop pressure.

Remove mechanical pressure gage, replace sensor, replace distributor.

Fire up engine.

That's how I've always done it. I don't recall what priming rod you should use for the AMC401, so you'll have to find it on your own. However, most oil pumps are driven by a flatted tang on the bottom of the distributor shaft, and that would be answered with a priming rod for a small block Chevvy - which you can get pretty much anywhere. I've seen engines that would also take a 5/16" or a 3/8" hex - but I think they were Fords. Expect to pay about ten bucks for a priming rod.

(Note for other readers - I've got a SBChevvy priming rod that I use for AMC242 - which makes it easier to find. Probably work for the AMC V8 as well.)

 

[cjben]

I am sure the 360 is the same as the 401. this is what I did for my 360. I took a 1/2 long shaft wood drill and ground the pointed tip off of it so it was flat,then take a 1/2 deepwell 3/8 drive socket and put it over the end of the drill that goes into the electric/air drill. the socket keeps the wood drill from slding off the oil pump drive. worked like a champ for my 360 amc engine,in a few seconds i had oil coming out of the head oil passages.

 

[KarlVP]

I just got done on a rebuild for a 401. Pull your oil filter housing assembly off and check to make sure the bypass valve isn't stuck open. (That tube on there with the bolt at the top) it holds a (4 inch or so) spring in places that keeps the oil pressure relief valve closed.

Hope this helps.

 

[KarlVP]

Also, you have to sign up for a free account, but this is a link to the troubles I had when working on the same problem with an AMC 401.

http://www.nw-wheelers.com/forum/showthread.php?t=15726

Our relief valve was stuck open. After we got that figured out, we packed the pump full of vaseline, primed it with a drill motor, and it was good to go.

 

[VAwheeler]

I noticed on Pirate the guys kept talking about taking the gasket off. Should this be done? I am planning on getting the rest of my motor back together tomorrow and would like your input BEFORE i get the motor back in the jeep. I didn't understand the purpose of the gasket in the first place but was going to use it since it came with it. Should I put some type of sealer on the gasket? (i.e. RTV, Indian Head, High Tack) I noticed when I pulled the old pump off the PO had put some type of red RTV or silicone on it.

Thanks for the help!

 

[Bouncy]

I packed the oil pump twice with vaseoline and nothing. So I had a spare distributor, cut off the shaft, ground down the dist gear and made an oil priming shaft. Stuck that in there with a drill motor and worked like a charm.

40psi at idle and 90 at 3krpm.

thanks for all the help guys.

 

[cheapjeep]

As a reference, you can also take a large cheap screwdriver, hammer the handle off of it, take a piece of copper tubing and use pliers to squeeze it so it won't fall off.

Cheap universal oil priming tool.

 

[Bouncy]

Thanks for the idea...thats not too bad.

 

[Slo-Sho]

40psi at idle and 90 at 3krpm.

That's off the scale! My H.V. Melling doesn't even go that high.:confused1

 

[Bouncy]

That's off the scale! My H.V. Melling doesn't even go that high.:confused1

It is a NEW tight motor with new bearings etc.

Pump is new gears in a new timing chain cover/housing. So all tolerances are tight.

10w30 oil in it.

After breakin, it should step down a bit.