My wife and I took a long drive down to look at a pair of ‘02 8.1’s HO’s with Hurth 2:1 straight drive, 8 degree down-angle transmissions. The boat is being parted out and sat for a couple of years. I was able to hear a cold start from when it was last winterized. The tank was removed so it was running off a gas can. They definitely have some deferred maintenance but started and ran well. I let them idle for about ten minutes and then did a compression test. I was going to do a leakdown but wasn’t sure that I would have power to run my compressor which turned out to be the case.
Results were:
Port - 175,170,175,165,165,175,150
Stb - 160,170,170,175,166,172,170,180
I think the #’s would be a little higher if it was fully warmed up and run under load. Obviously the 150 stands out on the port engine. I did that one twice, back to back with the same results. Maybe a little carbon build up on the valves on that cylinder? Once I get them home I can do a compression and leak down test under better conditions.
What do you guys think of those numbers overall and especially the 150? Also, both flex-plates were rattling but there were no shafts connected so not even a little bit of a load. Both engines seemed to idle great so it’s not clear yet if the rattling is actually the flexplates or rough/low idle.
My plan is to get them home in the next two weeks and get them setup and running in my garage and go through then top to bottom, replacing all of the consumable parts. So a bit of a project but these 8.1’s are impossible to find in really any condition.
One immediate question, I’m not quite clear on the cooling setup. One engine had both exhaust manifolds replaced. The setup on this boat was elbows bolted directly to exhaust manifolds, no riser in between (which I see as an option in the parts manual). Unlike the 454’s, are the 8.1’s raw water which is why they were replaced? I thought Crusader exhaust manifolds on all models were sealed glycol cooled. I know that some other 8.1’s, non Crusader do have RWC exhaust manifolds.
thanks
Bob
Results were:
Port - 175,170,175,165,165,175,150
Stb - 160,170,170,175,166,172,170,180
I think the #’s would be a little higher if it was fully warmed up and run under load. Obviously the 150 stands out on the port engine. I did that one twice, back to back with the same results. Maybe a little carbon build up on the valves on that cylinder? Once I get them home I can do a compression and leak down test under better conditions.
What do you guys think of those numbers overall and especially the 150? Also, both flex-plates were rattling but there were no shafts connected so not even a little bit of a load. Both engines seemed to idle great so it’s not clear yet if the rattling is actually the flexplates or rough/low idle.
My plan is to get them home in the next two weeks and get them setup and running in my garage and go through then top to bottom, replacing all of the consumable parts. So a bit of a project but these 8.1’s are impossible to find in really any condition.
One immediate question, I’m not quite clear on the cooling setup. One engine had both exhaust manifolds replaced. The setup on this boat was elbows bolted directly to exhaust manifolds, no riser in between (which I see as an option in the parts manual). Unlike the 454’s, are the 8.1’s raw water which is why they were replaced? I thought Crusader exhaust manifolds on all models were sealed glycol cooled. I know that some other 8.1’s, non Crusader do have RWC exhaust manifolds.
thanks
Bob
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