Oil pressure too high and now it is zero

[CJ7JEEP1979]

Good evening and Happy Holidays everyone!

I recently had my Jeep worked on at a top notch shop only because of the weather where I am at being too cold to work on my Jeep as I do not have access to work on it inside. It is a 1979 CJ7 with a AMC 304 and t18a 4 speed. It needed valve cover gaskets, oil pump gasket, rear main seal, steering shaft, water pump and oil pan gasket. All work was done and they put it together, drove it and it was fine. They called me to come pick it up. I tried starting it and it would not start in their parking lot. Once it started I had to keep my foot on the gas for about 10 seconds and was about to let off at which point the owner of the shop happened to be outside and he motioned for me to kill the ignition immediately.

It was shooting oil everywhere underneath and as it turned out the entire engine bay was covered in oil and it was running over the fenders. The oil filter, brand new, had blown apart from what turns out to be too much oil pressure. It was reading 130 with their gauges. They got another filter, cleaned it up, and the second filter did the same thing immediately. They took it back apart and put it back together and now there is zero oil pressure. Any ideas as to what caused this? The pump rebuild kit was from crown automotive and should have known something was up when they supplied gasket that came with it did not fit in any way shape or form. The parts fit in the kit but they had to get a different gasket. I have been waiting almost 5 days now and the new oil pump rebuild kit from a different company will be in sometime tomorrow (Monday) and we hope this will fix the issue otherwise if not they want me to order a whole new timing cover and oil pump etc etc.

The Jeep was fine before going into the shop other than the water pump had a bad loud bearing in it and was on its last leg and it leaked oil from various places. The oil gauge worked and now this whole mess is going on. Could a oil pump rebuild kit have caused this entire mess? The spring appears to be the correct length, nothing seems to be sticking, nor has any debris been found. The engine was rebuilt in the last couple of years by a previous owner who had the work done and it was bored .30 over, heads done, bigger cam put in and new oil pump put in along with a 4 bbl holley slapped on it. It runs like a scalded dog even with all of the leaks and now I am thinking about having it taken to a different shop because this one can not seem to figure something out that they have had more than enough time to do so. Any suggestions as to what could have caused this extreme high pressure to no pressure scenario?

 

[Project86]

Sounds like the hi pressure relief was did not function for some reason. Do a quick google search for AMC V8 oil filter by pass issues. This might a be a good place to start looking.

 

[CJ7JEEP1979]

Thanks for the lead, it turns out that now while waiting on the parts to arrive the oil pressure has bounced back up to over 200 as read with a mechanical gauge. They even tried cutting the spring back since it was going to be replaced again and that helped for awhile, but then it went to zero pressure and now back up to over 200. Something else, they keep having to make a gasket themselves for the oil pump cover as so far there are not any gaskets that fit it. Hopefully the new rebuild kit will have a gasket that fits otherwise we are stuck. I have read that this is the one area where you must use an actual gasket and not make your own as this can effect pressure but it makes no sense that gaskets do not fit this thing. They knew about packing it with Vaseline and priming it so they know what they are doing but this thing is just a mystery so far and it is looking like it will be well after Christmas before I have an answer and to find out what other expense I am going to incur to get this thing running right. I am going to start looking into a 350 transplant as these amc motors have too many weird things that I have never seen happen with other engines.

 

[TnCJ]

Sorry about your problems.
But I have to ask why[other than cost] you went rebuilt instead of new? Seems new would eliminate a lot of chances of something going wrong and I would think a new pump would come with a new gasket.
Hopefully you will get it straightened out asap.

 

[CJ7JEEP1979]

I went with rebuild with a kit because the oil pump is part of the timing cover and that is hundreds of dollars and there is nothing wrong with mine. Good point though. Also The problem is now fixed. Crown automotive sells horrible rebuild kits that do not work for the AMC 304 . The shop ordered a different kit from another company and that works great, no more issues and the oil pressure is fixed. The parts from Crown also blew my oil sending unit to my gauge and that had to be replaced. Everything is working now. The last two things I need to sort out now are replacing the wiper linkage, wiring the new wiper switch, and getting the fuel gauge to read more than a quarter tank when full. Thank you to everyone that responded. Even if others have had great luck with Crown parts I would stay away from them. Even though they won't pay I am still sending them the bill for the replacement parts because Crown needs to be held responsible.

 

[TnCJ]

Sounds great, glad you got it sorted out!!
And yes, most on here know the lack of quality on anything Crown, or Omix. Unfortunately sometimes they are the easiest and only source for hard to find parts for our old Jeeps.

 

[Patrick]

Great info. Posting the final outcome of the issues helps us all.