Warm engine knock '88 302
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Mountain Pass
Joined: Jun 2016
Posts: 207
Likes: 21
From: West Tennessee
Warm engine knock '88 302
I recently picked up a 1988 f-150 4x4, 5 speed, 302 shows 122k . In the past PO has taken off the injection and replaced it with a Jegs manifold and Holly 4bl carb. Said it leaked oil badly and probably needs a rebuild.
So I want To check it out because I don't take the word of a seller as gospel.
Got it running after an oil change that I drained a FULL 3 GALLONS of oil from the crankcase and cleaned up the plugs, cap, rotor and wires. Runs Great But ...
After it gets to full operating temperature a knocking can be heard that does increase with RPMs. I hear nothing at startup and running cold. If I had a bad rod bearing shouldn't I hear it more at startup than warm ?
I'm thinking put a can of STP in and see what that does. If it is a rod bearing I need a regrind now and if I run it with the STP and determine it's a rod bearing ... I'll still need a regrind.
Thoughts and input appreciated
Another option is buy a flywheel and clutch for my 300 4.9 and put that in 🤔
So I want To check it out because I don't take the word of a seller as gospel.
Got it running after an oil change that I drained a FULL 3 GALLONS of oil from the crankcase and cleaned up the plugs, cap, rotor and wires. Runs Great But ...
After it gets to full operating temperature a knocking can be heard that does increase with RPMs. I hear nothing at startup and running cold. If I had a bad rod bearing shouldn't I hear it more at startup than warm ?
I'm thinking put a can of STP in and see what that does. If it is a rod bearing I need a regrind now and if I run it with the STP and determine it's a rod bearing ... I'll still need a regrind.
Thoughts and input appreciated
Another option is buy a flywheel and clutch for my 300 4.9 and put that in 🤔
Lead Driver
Joined: Feb 2002
Posts: 7,959
Likes: 592
From: Greater Austin, Texas
If I had a bad rod bearing shouldn't I hear it more at startup than warm ?
No because your oil pressure is higher and oil thicker when cold. Do you know what your warm oil pressure is?
Hotshot
Joined: Jul 2020
Posts: 10,411
Likes: 2,612
From: Near Salt Lake City
Pull the oil pan, pump and pickup screen tube
Then you can pull a few main caps and rod caps
I think you will find you have spun a bearing and need a rebuild like the guy said
He put 12 quarts of oil in it so it wouldn't blow up while trying to sell it IMO
Then you can pull a few main caps and rod caps
I think you will find you have spun a bearing and need a rebuild like the guy said
He put 12 quarts of oil in it so it wouldn't blow up while trying to sell it IMO
Thread Starter
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Mountain Pass
Joined: Jun 2016
Posts: 207
Likes: 21
From: West Tennessee
Decision Made
I have decided ... after a warmup tonight and removing the belt still the noise. With a really bright flashlight I checked the oil leaks, front main seal, rear main seal, valve covers.
I'm going to pull the engine and plan on doing a rebuild. I will do updates as they come.
Thanks for all your input 🙂
I'm going to pull the engine and plan on doing a rebuild. I will do updates as they come.
Thanks for all your input 🙂
Thread Starter
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Mountain Pass
Joined: Jun 2016
Posts: 207
Likes: 21
From: West Tennessee
[QUOTE=manicmechanic007;209
He put 12 quarts of oil in it so it wouldn't blow up while trying to sell it IMO[/QUOTE]
He was quite upfront about the rebuild and it wasn't sold as a runner. I'm the kind to double check ... That's why I was asking for input. Thanks for your help
He put 12 quarts of oil in it so it wouldn't blow up while trying to sell it IMO[/QUOTE]
He was quite upfront about the rebuild and it wasn't sold as a runner. I'm the kind to double check ... That's why I was asking for input. Thanks for your help
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