Motor trash?

jdtower23

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May 12, 2007
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I'm the "Adjusting Rockers 4.3" guy if anyone doesn't know....while trying to start the thing it froze up again on me....when I got it to move last time it still had a tight spot at a certain point in the rotation.....it was spun over several times but even sounded with the starter like there was a certain point where it slowed down....

I didn't see anything abnormal with the heads off except a water spot on affected cylinder wall (head gasket)

Anything else I can try before giving up?

Thanks
 

MikDee

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Jun 6, 2007
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4,745
Re: Motor trash?

I do find it hard to believe, but maybe a piston is binding at one spot in one of the bores (bulge in the wall?) for some reason? Or, maybe one of the connectig rod, or main, bearings is binding up at one point? shoot, if the cam, timing chain, & gears, plus the oil pump are all in the motor, maybe one of them is binding, what else is there? nothing else to check?
 

Bondo

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Re: Motor trash?

If it binds Every time Around,............ I'd suspect the Bearings,... Mains, or Rods......
 

jdtower23

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Re: Motor trash?

It was pumping about 38PSI oil pressure according to the gauge while cranking so oil pump was working....

The bores all looked pretty good.....like I said there was the one water spot...you could feel it with your finger....I used some steel wool and smoothed it out....

You think the timing chain is a possibility? Last time I moved it a little I did hear a slight metallic pop....

I am going to post a pic of cylinder where gasket was blown....

Thanks
 

jdtower23

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Re: Motor trash?

boat002.jpg


This is before any clean up work, tapping the head bolts, etc....
 

Bondo

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Re: Motor trash?

Is the motor still in the boat,..?...

And reduce the size of your picture alittle bit......
 

jdtower23

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Re: Motor trash?

Sorry about that.....yes, still in the boat....
 

wire2

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Jun 25, 2007
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Re: Motor trash?

You can narrow it down considerably by pulling the timing chain off temporarily & turning the crank.
 

jdtower23

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Re: Motor trash?

Sprayed some Deep Creep in the plug holes, and it helped.....it "feels" like one piston is tight....it's getting looser though.....I guess I'm going to keep working it to free it up....before I tore it down every cylinder but the affected one was right around 160 PSI compression...tested completely cold....difference of only 9 PSI between lowest and highest....I didn't get a reading on cylinder where gasket blew because of water.....maybe that spot where the water was leaking in is causing this.....
 

mkpj1

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Jul 11, 2006
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108
Re: Motor trash?

I guess I missed something in the other posts. What was the compression of the affected cylinder? It really doesn't matter what the others are if you have one low one. What is your compression now? Let me get this straight, Your turning it over with the starter and it just binds to a stop? Then your able to get it turning "with barely one hand" again. Pull your starter and bench test it and make sure it's releasing. Otherwise, I'm with bondo, sounds like a bearing may have slipped. Pressure sounds good though. I agree that you need to remove your timng chain to isolate but this is getting to the point that you need to take this to a professional that can touch your motor and diagnose it properly.

Good Luck
 

jdtower23

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May 12, 2007
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Re: Motor trash?

I never got a reading on the affected cylinder because water was still spitting out.....I think I will retest all of them tomorrow....

There is a spot while turning where it's slightly harder to turn...it seems like spraying some sea foam in the plugs helped and it's not as hard....after doing this I was able to crank it again and it spun freely....I think I must have a rust spot somewhere.....I'm going to keep trying to work it back and forth and see if that helps....

I will post compression tomorrow if I can stand to do it....was 106 here today :)
 

mkpj1

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Re: Motor trash?

Ahhh, water in the cylinder from....blown head gasket? Ahh Haa, see i never saw any of that. Look if it ran with water in that cylinder it could have bent something underneath, a rod, tweaked a bearing, shoot I've seen rods just break. Crank can be tweaked? See, water don't compress. Whatever is tweaked is pushing the piston at an odd angle into the cylinder now creating a "water spot" as you say. If your starter can't push the motor at times, thats not good.

did you pull the pan and look up at the mains and rod of that cylinder?

Here's what i would do and I am no expert but have been into a an engine or two. Before you button it up for compression, get an inside micormeter and see if that cylinder is out of round especially at this "water spot" you speak of. Out greater than .003, rut rho shaggy! Stop and proceed to a machinist to discuss your options. those tolerances may be different for you motor but will be close. If okay, get compression, see what it is, 20PSI difference, proceed to machinist and discuss your options. If it isn't, crank it with the starter and check your oil pressure. if it's within specs, and the MOTOR DOESN"T BIND AGAIN!! Friggin crank it already. If it binds at all, Take it to a machinist.

Now this is what I would do! You already took the chance on your own that you could get this done and it's looking like it is too much. Your safest route is to take it to a honest professional and get it done right. there is nothing wrong with throwing in the towel. I've been there! You have a solid understanding and should be able to explain what's going on enough to get this thing fixed right. The chance you take with all this is that you frag the block when a rod breaks or spin a bearing. You have to ask yourself is the education worth it? I mean, maybe it is just rust? But we can't tell at this point through the computer. Get someone to touch it.

Good Luck JD
 

bomar76

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Jun 27, 2002
Messages
1,963
Re: Motor trash?

Sure looks like rust in the lifter valley in those pics....think there is a lot more going on w/ that hunk of cast iron than has been reported.
 
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