Low to NO Oil pressure 304 v8
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=24334
Printed Date: Apr/16/2024 at 3:07pm
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Topic: Low to NO Oil pressure 304 v8
Posted By: kovacjr
Subject: Low to NO Oil pressure 304 v8
Date Posted: Nov/15/2010 at 9:18am
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Well over the weekend I had been out wheeling and of course in the woods the oil pressure started to get very low. When crusing home the pressure was a max 8psi. Before I set off back home I dumped a bottle of STP oil treatment in hopes it would just help the wear.
One of the lifters also started to tick.
So now the question is do I just replace the pump gears or replace the adapter too with one of the newer designs? I was looking at the Bulltear pump kit and also the new adapter housing but they do not show stock of the housing due to a bad casting run. He also had a stainless wear plate for the gears. i do not want to change the whole timing housing as the motor just needs to get me through another year or less as I have a 360 that I need to build to put in. I also want to convery to a Muncie SM465 4sp trans and rebuilt the transfer case and was hoping that the motor can be in a year and the trans be this winter, I really didnt want to have to shell out all the cash for doing it all at once.
------------- Jason in NJ 72 CJ5 304 |
Replies:
Posted By: poormansMACHINE
Date Posted: Nov/15/2010 at 9:21am
| Before you toss a pump at it you need to determine if that is the fault. If the engine swallowed a bearing, all the pumps and STP you can toss its way won't fix it. |
Posted By: billd
Date Posted: Nov/15/2010 at 9:23am
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How do you know it's the pump? could be the relief valve is stuck open, could be a nasty bad filter, could be the pan is up against the pickup screen, could be SHOT bearings, (or just a plain worn out engine), in which case a "new pump" won't do much for you..... How many miles are on it? Have you screwed in a known good mechanical gauge to confirm the pressure (the lifter is a good indication, but not the final say) If it's the pump, indeed new gears and his wear-plate kit could be a huge help.... -------------  http://theamcpages.com" rel="nofollow - http://theamcpages.com http://antique-engines.com" rel="nofollow - http://antique-engines.com |
Posted By: kovacjr
Date Posted: Nov/15/2010 at 9:53am
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Well the ODO reads 73000. Title says actual but anyone can roll it back or replace the gauge. When I replaced the rear main seal the rear main bearing was not in great shape but as it made no noise we put it back in anyway. The sump should be ok as the pressure gradually got worse. I havent taken anything apart yet to see as I wanted some input first.
I have a AC filter in there and about 300 miles since the oil change. I think some 5-40 or 10-40 oil
So take the adapter off and check all the internal parts and gears.
As I said I dont want to dump a bunch into this motor as I do have a 360 in the garage that just needs to be taken apart and rebuilt. Though the Trans that is in there both 2 and 3rd syncros are shot as thats why I wanted to do the trans 1st upgrading to the Muncie 465 then the motor 2nd. Doing both at the same time is just going to consume too much money too fast.
Any guys in the NJ area on here? Having a local AMC guy would be nice. ------------- Jason in NJ 72 CJ5 304 |
Posted By: poormansMACHINE
Date Posted: Nov/15/2010 at 10:00am
What's on any odometer is meaningless. How it was maintained is what matters. Looking at a bearing doesn't say much for clearance and it didn't look great visually the bearing and the crank are pretty much gone then. I take it that leaves 12 other bearings you didn't see. |
kovacjr wrote:Posted By: CR CRUISER
Date Posted: Nov/15/2010 at 10:11am
| Once upon a time there was a Jeep sevice bulletin about the front axle smacking the oil pump housing. It would slightly deform the relief valve port and cause the valve to stick. It might be something as simple as that. |
Posted By: billd
Date Posted: Nov/15/2010 at 11:12am
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Thus my mention of the valve sticking..... and pmm is right - I've got two examples myself - one is Luke's and the other my 4.0. each with 100,000 miles on the clock, both look like 300,000 inside! His ended up with no pressure, but the sender stuck from the sludge and the light never came on, and pressure readings were "weird" at best. The 4.0 had the distributor drive and driven gears chewed to bits - something I've not see on a 4.0 until then. ------------- http://theamcpages.com" rel="nofollow - http://theamcpages.com http://antique-engines.com" rel="nofollow - http://antique-engines.com |
Posted By: kovacjr
Date Posted: Nov/15/2010 at 12:34pm
No we did not look at the other bearings. The motor burns no oil and ran strong. Plugs were clean and dry when I replaced them.
As for the bearings I dont know what the clearance was I was more concerned with just replacing the badly leaking oil seal. The motor before the lifter noise ran smooth at idle about 700rpm with no shaking. The lifter is causing that cylinder to run poorly so at idle with very low pressure it was very shaky but above idle runs smooth again as its pumping more oil in my opnion.
As for mileage thats why its really not important to me. I wont just assume that 73k means anything. I drained and refilled the 3sp trans when I bought it and it was nothing but sludge. The engine was maintained better by looking at the oil, plugs and compression. it is a 1972 so these are things I've expected to come up. Once Im done though I know I'll have something very road/trail worthy.
I bought this Jeep mostly due to the clean frame with some minor rusted areas and new fiberglass tub, fenders and hood. ------------- Jason in NJ 72 CJ5 304 |
Posted By: purple72Gremlin
Date Posted: Nov/15/2010 at 1:50pm
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Posted By: 17tamx
Date Posted: Nov/16/2010 at 5:51pm
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Did the tick from the lifter come before the drop in oil pressure? After? At the same time? Pull the valve cover and check for a broken rocker arm and check the pushrods and how the pushrod feels in the lifter of the one that is loose. You may have had a lifter come apart and now have an excessive internal oil leak that the pump can not keep up with. ------------- Kirk P. Fletcher 70 AMX BBG w/Shadow 390 4sp 71 SC360 Wild Plum Ram Air 4sp 67 Rogue Convert 343 4sp 66 Rogue Hardtop 290 Auto 66 440 Convert 232 Auto |
Posted By: 69 ambassador 390
Date Posted: Nov/16/2010 at 7:01pm
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Yep. And a broken valve spring could cause the same thing. The lifter gets too slack and the piston pops the little clip off and Whalahhhh. Internal oil leak. ------------- Steve Brown Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |