Unbelievable.... 304 rebuild starts

[nivensid]

I have an older thread on replacing the AMC 258 i6 / 4.2l 6 cylinder in my CJ7 with a good running AMC 304 V8 out of my rusted CJ5 .
I pulled the motor last week and started inspecting it hoping to just clean it up and install back in the CJ7 .
Well here is what I found when I took off a valve cover and the intake. I was astonished to say the least. The motor ran good with out any usual knocking or ticking that would be a bad sign. No smoke at start up or any other time. The oil pressure was low but from what I have read this is a common problem with the oil pump and I never verified the oil pressure with a mechanical pump.
I will take it apart and let the machine shop inspect everything and hope I can just re ring it and put it back together. I know.....that's a long shot.
The plugs looked good so I am hoping that is a good sign.
I want to keep the AMC 304 and have no desire for a 360, I'm too old to care about more power, this is just a weekend street toy.
Check this out...

 

[Torxhead]

Best of luck with your rebuild, the AMC 304 is a great CJ engine. That one really appears to be poorly maintained.

 

[gert]

Wow such a shame, if you rebuild it please share with us.


Sent from my iPhone using Tapatalk

 

[mstar]

We call that " Sludge" not really that unusual .Hot tank it and rebuild. Could be a crankcase ventilation problem. Plugs look good !

 

[Lumpy Grits]

Holly !
Wonder what the oil pan looks like?
What oil was be'n run?

LG

 

[nivensid]

Holly !
Wonder what the oil pan looks like?
What oil was be'n run?

LG

Lumpy, the oil pan didn't look bad at all, not sure what oil the PO used.

 

[nivensid]

We call that " Sludge" not really that unusual .Hot tank it and rebuild. Could be a crankcase ventilation problem. Plugs look good !

I felt better when I viewed the plugs for sure, plan on pulling the heads tomorrow for a closed look at the cylinders. Hope to keep it simple but will have to wait and see after everything is cleaned up.

 

[tarry99]

I felt better when I viewed the plugs for sure, plan on pulling the heads tomorrow for a closed look at the cylinders. Hope to keep it simple but will have to wait and see after everything is cleaned up.

Nothings simple.........It's apart now .........rebuild it.

 

[Hedgehog]

I'd say no matter what oil he used he used it for a VERY long time. Sludge like that indicated that he rarely changed his oil. I bet a good cleaning and a new set of rings along with honing the cylinders will restore the engine to top condition.

 

[Lumpy Grits]

Not only had that oil been in for a long-long time.
That is also an indication of a lot of very short trips and/or a 'cold' engine.
I would be curious to know what's the t'stat temperature rating is.
LG

 

[nivensid]

Pulled the heads today, didn't see any scaring on the walls. The top of the bores had a very slight lip, couldn't be more than .002 - .003 but that was by feel.
Need the more experienced friends here to let me know if they see any bad issues in the pics before I go to the machine shop after Christmas.

 

[Lumpy Grits]

Doesn't look all that bad.
Hot tank and do a penetrate test on the heads.
Fair amount of rust in the water jacket....
LG

 

[mtnwhlr]

Unless you have the money for a rebuild I would just clean it all up and put it back together. It looks to be in good shape just not maintained.

 

[nivensid]

Unless you have the money for a rebuild I would just clean it all up and put it back together. It looks to be in good shape just not maintained.

What all do you mean when you say " just clean it up"?

 

[Lumpy Grits]

Hot tank-pressure wash block and heads etc. Get some 'plasti-gage'(sp) to check bearing clearances.
LG

 

[mtnwhlr]

What all do you mean when you say " just clean it up"?

I meant clean all the gunk out of it. If it ran good the plugs look good and it wasn't using oil. If it was me I would't rebuild it just because it was full of gunk. I would clean it out good and put it back together and run it. But then I'm a cheap .

 

[007]

I gotta agree with mtnwhlr...

Gunk is just that. You're in pretty good shape everywhere else it seems. Clean it good, flush it good and seal it back up and go...

My 2cts.

 

[mstar]

At least you would have a clean worn out old AMC 304 .

 

[mtnwhlr]

At least you would have a clean worn out old AMC 304 .

So why do you think it's worn out?

 

[Lumpy Grits]

At least you would have a clean worn out old AMC 304 .

Look again at the pictures of the spark plugs the OP posted. That engine ain't 'worn-out'.

LG