FYI For some odd motor sounds

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Smkozma69
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Joined: Thu Feb 07, 2019 1:11 pm

FYI For some odd motor sounds

Post by Smkozma69 »

Hi guys, I just wanted to pass along some information that may be helpful to someone some day. I’ve had an odd motor sound coming out of my 1980 360. I’ve been around motors most of my life and I have never heard anything like this before. It was a high pitched clangy knocking sound. It was very predominate at the oil filler tube. I pulled the motor and took it to my local speed shop. They called me today to let me know that it was something wrong with the fuel pump arm! The pump is new and it took a year to happen. They are not sure as to why this happened but they said it’s wearing very odd on the internal part that drives the pump. Just another thing to check out! It was a good thing I pulled it out though because the previous owner claimed he rebuilt the motor, which my machinist said they did but they never reconditioned any of the rods. We will be reconditioning them or replacing them along with ARP studs to give me a better piece of mind.
1980 J20 with Modified 360-60over, comp cam, roller rockers, roller chain, HEI distributor-T18, 4inch lift 37” copper stt pro’s on 20” ballistic wheels
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Stuka
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Re: FYI For some odd motor sounds

Post by Stuka »

I have seen a fuel pump make weird noises.

When they say it was wearing strange inside, do they mean the cam lobe? If that was the case, it almost makes me think the arm of the pump was made of hardened steel. Typically the arm should be softer than the cam, so the arm wears and not the cam.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
Smkozma69
Posts: 17
Joined: Thu Feb 07, 2019 1:11 pm

Re: FYI For some odd motor sounds

Post by Smkozma69 »

Apparently that was just the beginning of the motor issues... I just got a call from the speed shop, they said I need a new block. The previous owner had at one point severely over heated it. Two of the cylinder walls are shot and to top it off it’s already at 60 over. Can someone please give me an idea of the years of motors that will work with my 80 j20? And will a 401 work with my set up? Thank you in advance.
1980 J20 with Modified 360-60over, comp cam, roller rockers, roller chain, HEI distributor-T18, 4inch lift 37” copper stt pro’s on 20” ballistic wheels

KJ Ryu
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Re: FYI For some odd motor sounds

Post by KJ Ryu »

AFAIK, any AMC V8 will drop in.
Ron

2005 KJ, Hit-n-Run, 2am 6-17-2012, Totaled. :mad:
1977 SJ J10, 4v360, T18, D20, 37x14s, SOA & SF on tons, still ugly.
1978 SJ Wagoneer, 4v360, QT, 33x12.5s, lift by Sawzall :-bd NOT Running :(
1977 SJ J10, SniperEFI 401, QT, D44s, 31X10.5s :fsj:
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Stuka
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Re: FYI For some odd motor sounds

Post by Stuka »

KJ Ryu wrote:AFAIK, any AMC V8 will drop in.
Well, almost. There are AMC "short deck" (66-70) and AMC "tall deck"(71-91) blocks.
Smkozma69 wrote:Apparently that was just the beginning of the motor issues... I just got a call from the speed shop, they said I need a new block. The previous owner had at one point severely over heated it. Two of the cylinder walls are shot and to top it off it’s already at 60 over. Can someone please give me an idea of the years of motors that will work with my 80 j20? And will a 401 work with my set up? Thank you in advance.
Technically any "3rd gen" tall deck AMC block will "bolt in", this covers the 304, 360, and 401. But I think accessory drive mounts changed at some point. But you should be safe with any mid 70's and up engine. The starter setup changed in the late 80's, but I don't think the block changed for this.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
Smkozma69
Posts: 17
Joined: Thu Feb 07, 2019 1:11 pm

Re: FYI For some odd motor sounds

Post by Smkozma69 »

Thank you for the info. The hunt begins
1980 J20 with Modified 360-60over, comp cam, roller rockers, roller chain, HEI distributor-T18, 4inch lift 37” copper stt pro’s on 20” ballistic wheels
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