Another rebuild ?
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Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=33379
Printed Date: April-29-2024 at 11:10am
Topic: Another rebuild ?
Posted By: malibud
Subject: Another rebuild ?
Date Posted: April-19-2014 at 10:09am
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Sorry about all the post but long story short I bought a cheap boat with a cracked block(97 sport w/ gt40) found a used excalibur w/ 2000hrs. and it got damaged in shipping So I am now back to where I started from. I think it is best to stick with the GT40 and have it rebuilt Locally or order a new long block Heres the question There is a very reputable race engine builder/machine shop who said he would do it no problem. I would like to go here but he has done boats but not that many. Or do I order a Long Block and if so where ? 1800 runsnew got good reviews but said their heads were the same as GT40s but did not have any markings on the outside ? they said the insides were all the same Any suggestions thanks |
Replies:
Posted By: gun-driver
Date Posted: April-19-2014 at 10:17am
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If just the blocks cracked get a block from a salvage yard and use everything else from the original motor. Unless you plan on putting a roller cam in its just a 351 block. Don't know how many hrs were on the original so you may want to replace some things while your in there. |
Posted By: malibud
Date Posted: April-19-2014 at 10:20am
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625hrs . But if I get a junkyard motor that means I will have bore it. Nwe pistons. So If I have the heads magnafluxed and they check out ok should I have new valves put in and rebuilt? thanks |
Posted By: gun-driver
Date Posted: April-19-2014 at 10:48am
Not necessarily if the cylinders are in specs a hone and rings would do it. Most salvage yards have running motors for less than $500 strip the block sell or junk the rest. How did it crack overheat or freeze. If it was an overheat I would check the heads for warp/cracks if it was a freeze I would think the heads are fine no need to change valves with that low of hours. |
malibud wrote:Posted By: Waterdog
Date Posted: April-19-2014 at 12:08pm
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Dan, How about a 351w stroker short block ? Have your heads serviced, bolt them on. All your stuff will bolt on. Just the cracked short block lift over. Reid P is in Mooresville @ Race City Marine and knows the best shops close to you to get one. (or a standard short block) ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: Donald80SN
Date Posted: April-19-2014 at 12:22pm
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Also, you may want to consider going to Clear Water Cylinder Head in Florida to get reconditioned GT-P heads. They are better than the stock GT heads and MAYBE less expensive then going through and reconditioning what you have. Also, Paul Carpenter in Albermarle, NC has a 79 351 motor for sale with trans for sale. Also selling a bare hull. I believe it is on this site or maybe e-bay. FYI, Donald |
Posted By: malibud
Date Posted: April-19-2014 at 12:41pm
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Well... I just got off the phone with race city marine and they told me to get the excalibur Gm engine rebuilt. More horse power and readily available parts (plus i have new manifolds for it) Any others want to chime in ? |
Posted By: gun-driver
Date Posted: April-19-2014 at 3:43pm
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I didn't know the Excalibur was still in the picture. I would think a block on a 625hr motor would be cheaper than a complete rebuild on a 2,000 hr motor. What are you going to do with the old motor then? |
Posted By: malibud
Date Posted: April-19-2014 at 3:57pm
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Well I have 2 motors ford and Excalibur Gm . The ford has a crack block from freezing. I think cost would be about the same . I have new manifolds on the excalibur, and the ford would need them but the pigtail and new mounts for the Gm make it a wash. I was told on separate occasions to beware that the ford computer would not work if the block has been bored more than 30 over . So getting a factory rebuild from say Jasper I would not know how much it was bored. So either way one needs a rebuild and put it in Just which one? kind of leaning toward the GM going from what Race City has said about it being a more modern engine and part availability. |
Posted By: malibud
Date Posted: April-19-2014 at 3:58pm
| The excalibur will need a new oil pan and oil pump/pick up since it was dropped on the oil pan |
Posted By: Gary S
Date Posted: April-19-2014 at 4:03pm
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As long as you know the Chevy's block is ok and just needs a rebuild I think I'd go with the Chevy. But I don't see why an overboard block would change running with the computer. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: malibud
Date Posted: April-19-2014 at 4:19pm
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chevy block was running with 2000 hours. the compression was a little iffy high was 190 and low was 145 GM service manual says Low needs to be 70% of high. The chevy block looks better ford may have seen a bit of salty air. The race city Marine mechanic said he was told by PCM that it had been a problem with ford's FI system and going over 30 it would not run. Does not make sense to me but I would think Stroking it would definitely lead to problems... Never heard of anyone having a stroked GT40 |
Posted By: gun-driver
Date Posted: April-19-2014 at 5:02pm
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I just can't see spending the money to completely rebuild a 2k hr motor that you have to change wiring harness, motor mounts and probably some other thing once you get into it. When all you need is a block for a motor that is ready to drop in. I would doubt you could add a stroker block without being able to remap the computer. But you could throw a roller cam and a little better heads in it if you wanted.  70% would be a stretch if you ask me. I've always been under the understanding that you want to be within 10% of the best cylinder. Edit: I would like to add that if you decide to go with the Excalibur I would be interested in some parts off the old motor, if you would need some extra cash. 
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Posted By: TX Foilhead
Date Posted: April-19-2014 at 5:14pm
| The GT40 computer has the ability to learn a little, this keeps it running as things wear just like a car. What it doesn't have is the ability to adjust to much increased air flow because it has no sensor that can tell that is happening. Basically if you do something that causes more airflow then you end up with the motor running too lean because it can't add enough fuel to compensate because it doesn't have a Mass Air Flow or O2 sensor to tell it to adjust. |
Posted By: malibud
Date Posted: April-19-2014 at 6:26pm
| Good point gun driver... If I am lucky I could reuse those heads from the ford. Can buy a new block and use my old pistons ? Are 351w blocks still made? Think I'm going with the ford. Oya nice explanation foil head very informative |
Posted By: gun-driver
Date Posted: April-20-2014 at 3:34pm
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Start calling junk yards you should be able to find if not a block a running 5.8 This is all assuming the heads and everything else is good. You never said how the block cracked that may have a lot of bearing on which motor to go with. |
Posted By: malibud
Date Posted: April-20-2014 at 4:27pm
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Going with the ford gt . It has a cracked block I think. The PO brought up here from Florida and did not winterize it . So it got close to 0 degrees here and cracked the block . The manifolds don't look good either. I hope bring to the engine builder soon. Is there a list anywhere that I can give that is marine specific ? I have the pcm manual with torque specs but did not know if I needed marine specific pistons or anything because I assume I will have bore anyt block I find. Thanks Dan |
Posted By: Hussler
Date Posted: April-20-2014 at 5:16pm
| I would probably buy a reconditioned block, I think Ford racing still sells them. Then throw all your crap into that block. By the time you break down a junkyard block and hone, cam bearings, freeze plugs, clean ect youll be a bunch of time down/money for the same thing |
Posted By: Waterdog
Date Posted: April-20-2014 at 5:41pm
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The machine shop should know what to do. It's recommended to bore the block +.001 on a marine block (not everyone does) Marine head gaskets are the big difference in the gasket set. Marine cams are also a special grind. Most guys here use Cam Research cams. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: Hussler
Date Posted: April-21-2014 at 4:43pm
I have never heard this before, so if you have a 4" bore it should be 4.001? Doesn't sound right to me as the piston ring would no longer be a perfect circle |
Posted By: Dreaming
Date Posted: April-21-2014 at 4:48pm
The ring end gap measurement tolerance is greater than .001, so I would guess that the extra bore would still not put the ring gap out of tolerance |
Posted By: Waterdog
Date Posted: April-21-2014 at 5:16pm
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Excluding standard / reverse rotation the piston clearance is different in marine / auto engine machining because marine engines always have a load on them. Some guys say it really dosen't matter. Thats why its important the machine shop should be familiar with marine applications. In reverse rotation engines and stock pistons with piston pin off set the pistons are installed backwards and the crank shaft seals are also made to run reverse. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |