Replace head gasket, rebuild, or repower?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=36910
Printed Date: October-07-2024 at 4:25pm
Topic: Replace head gasket, rebuild, or repower?
Posted By: tjdarland
Subject: Replace head gasket, rebuild, or repower?
Date Posted: July-31-2015 at 3:30pm
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Hey everyone, I have a 1980 Ski Nautique, stock 351, with 900 hours. We've had the boat for 4 seasons and love it. Last weekend I checked the oil and it was thick and foamy. Pretty sure I've got a blown head gasket. I'm 99% sure it was not caused by an overheat situation, but probably due to age. It's at N3 Boatworks, the Nautique dealer in Indianapolis. I'm having them do a quick structural check before we decide our next move. I'm leaning toward a repower with a stock 351 from Jasper. A couple of questions: Pros/cons of just replacing the headgasket, rebuilding, or repowering? If we decide to repower, are there other engines I should consider aside from the 351? They are getting harder to find and therefore more expensive. The remanufactured engine will run around $2800 from Jasper, and I estimate around $1000 to have someone drop it in if I decide not to do it myself. Lastly, I plan on rebuilding the carb and changing from points to electronic ignition. Any advice on the overall project would be greatly appreciated! Todd 1980 Ski Nautique ------------- tjd |
Replies:
Posted By: JPASS
Date Posted: July-31-2015 at 3:40pm
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I'd see how good/bad the engine is before I spent the money on a repower with the same engine size. 900 hours isn't much at all. Hell, our '92 has 1810 hours on her and is still running strong. I'm pretty certain replacing the head gasket will be considerably cheaper than a repower. ------------- '92 Correctcraft Ski Nautique |
Posted By: GottaSki
Date Posted: July-31-2015 at 3:46pm
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I concure, 3800 dollars just to get back where you were doesn't sound very cost effective. 900 hours isn't much for hours. My friends 351 didn't frag unto 2800 hours. I say throw some gaskets at it.and go boating. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Hollywood
Date Posted: July-31-2015 at 3:48pm
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If the head gasket is the problem fix it and put it back together. Like they ^ said, 900 is not worth a complete tear down. When is the last time you checked the oil and it was good? ------------- |
Posted By: Orlando76
Date Posted: July-31-2015 at 3:49pm
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With what John said. If you do decide to do a repiwer, I highly recommend ATK from Summit. My experience is they did a better job than Jasper and are a wee less plus free shipping but Jasper may be free too idk. I wouldn't think twice about 900 hours, he11 just replace the head gaskets if it checks out ok since you know the engine and what to expect. ------------- Please support The Cystic Fibrosis Foundation 1976 Ski Nautique 351 Escort 1993 Ski Nautique purple and black 351 HO PCM |
Posted By: Orlando76
Date Posted: July-31-2015 at 3:52pm
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And I'll bet you're looking at $4500. I'm in the middle of a repower now.... It grows because of "while I'm at it" ------------- Please support The Cystic Fibrosis Foundation 1976 Ski Nautique 351 Escort 1993 Ski Nautique purple and black 351 HO PCM |
Posted By: TRBenj
Date Posted: July-31-2015 at 4:45pm
| Agreed there are better options than a long block but you first need to find out what's wrong. Chances are good it's not a head gasket problem. It would be a shame to find out it was a cracked intake or exhaust manifold after you bolt the offending part back onto a fresh block. |
Posted By: KellyfromVA
Date Posted: August-16-2015 at 2:06pm
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Before doing anything too extreme, consider pulling your exhaust manifolds and check for rusting right where the exhaust manifold meets the head (where the exhaust would be). I ran into the exact same assumption when my thermostat stuck closed and the temp got a little too high. Next time out, I have milkshake where oil alone should have been. After pulling the heads and seeing no blown areas in the head gaskets nor the intake manifold gasket, I could pretty clearly see which cylinders were getting water. The corresponding exhaust ports has rust near the bottom and so did the exhaust ports of the same side exhaust manifold. Once I swapped out the bad manifold with a new one (and put it all back together), everything seems to be fine now. ------------- 1980 Ski Tique |
Posted By: Jonny Quest
Date Posted: August-16-2015 at 2:28pm
Listen to TRBenj. I also doubt that you have a bad head gasket. Possible, but less likely than cracked exhaust or intake manifold. As long as you didn't run too long on milkshake oil, you could reasonably get away with MUCH less than a re-power. The 351W is a good engine. No reason to give up on it yet. N3 should have a good marine mechanic, you'll know very soon what you're looking at. Now if you want more "ponies" then a re-power might be the way to go. You can easily get 300+ HP with the right re-power. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
TRBenj wrote:Posted By: tjdarland
Date Posted: August-23-2015 at 6:38pm
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Thanks for all the advice, everyone. Here's what we've done so far: 1. Compression test...good 2. Changed the oil and ran it off the water for a while to look for a crack in the intake manifold, etc...good 3. Ran it for about 3 hours yesterday on the water...good. It ran well and the oil is clear. I'll check the exhaust manifold next weekend. Right now it's still a mystery, but at least we're back on the water. Todd ------------- tjd |