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1984 454bs with low compression update

nightstalker

Regular Contributor
"If you have been following my

"If you have been following my thread about the 454's with low compression, here is the final chapter. Originally, the twin 454's in the vessel I looked at had very low compression (mostly 60's and 70's with one 30, one 35 and one at 50). I walked away from the deal and got my full deposit back. The vessel's owner called me to convince me to take a sea trial at his expense with a second compression test to follow. I did that today. The boat ran good. The twin 1984, 454-370 HP motors ran well. She did 14.5 knots at 3400 RPMs and 19.7 knots at 3950 RPMs (vessel weighs 35,000 lbs). There was no smoke at startup, temperature topped out at 165 and the oil pressure was excellent. We only had her wide open for a few minutes. The mechanic met us at the dock to do the second compression test (hot). Compression improved but not up to spec. The compression was between 75 and 95 on one engine and 80 to 105 on the other. I've always been told that anything below 100 is a sign of danger. The mechanic told me that these readings showed a somewhat "tired" set of 25 year old Crusaders but felt that I should reconsider walking away and lower my offer substantially. I was surprised that the readings were still low considering that the engines performed so well on the sea trial. Also, I was surprised that the compression improved to these much higher readings across all cylinders after believing that a sea trial would not improve compression very much. Something had to "give" in order for the compression to go up that much in both engines. The mechanic said that he would have preferred that we ran the vessel at full throttle for 10 or 15 minutes rather than the 2 or 3 on the trial. He said that he has seen engines with readings like these go on running for many years but that you never know for sure. He said that the Crusaders are "bullet proof" engines and that these two could still have a lot of life left in them. The broker suggested that I offer the owner $20,000 less than my original, already "low ball" offer, but I don't know if I want to do that along with the fact that I doubt the owner would go for it. He keeps pointing out the fact that the engines ran well on today's sea trial. I think I'll end up passing on this vessel but thought some of you may be interested to hear of the compression inproving.
Gary (Nightstalker)"
 
"Personally. I wouldn't bu

"Personally. I wouldn't buy a boat that heavy with gas engines in it. You're looking at 30 to 40 gallons an hour! That's diesel territory.

That said, I'll bet those engines will run for years like that, especially if you don't run on plane all all the time. At the very least they will start burning some oil, which simply means you'd have to add some now.

Jeff"
 
"I agree. A vessel like that n

"I agree. A vessel like that needs to be run at trawler speeds to conserve fuel. I'm bacically looking for a live-a-board for the summer months, so speed isn't an issue. I wouldn't give the seller the agreed upon price with engines that have low compression.
Nightstalker"
 
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