New guy, Newish Boat

One thing, as far as putting a lot or torque on the crank bolt...

I made that suggestion a while back in another thread, I'll see if I can find it.

Anyway, I was told that's not the best way to break free a stuck engine. The logic being, that if you break that bolt, then you've got some problems on your hands.

I'll see if I can find the thread because it had some better suggestions, but in the mean time, just go about it carefully.

Ah ha... Last thing I want to do is make this thing worse and the leverage on a single bolt makes sense.

Pulled the battery out of my tahoe in stuck it in the boat.

Horn Works, Got Two Green Lights on the key pad, Bilge light on the key pad lights up but the bilge doesn't run. Still nothing on the accessory pad. Is there somewhen that can test those?



Annnnnnd...



2 of the pistons have some gouges in them. And the rear most port side piston picture is beat to a pulp. So two starboard side pistons with dings and then the port side pictured. Cylinder wall might be salvageable. The head is also beat to crap and one of the valve seats is out and wedged against the valve itself. (I didn't get a picture).

I'll pull in the next week or two and take it to a machine shop to see if the block can be salvaged.

At least I had good help.

IAughtNaut wrote: Treybizttu wrote: Also finally crawled back under since I didn't Remember seeing a paddle wheel for the updated speedo but sure enough there is one about mid way down the keel dead center. It's behind the plug and the farthest forward water intlet. It's in front of the back water inlet but offset from it somewhat. would be curious to see a picture, if its offset you shouldn't have an issue with prohibiting water to the intake, but if its on the center of the keel I would assume they had to grind it down to fit the flat housing and that might have left it recessed behind the ridge of the keel. I wonder if that would cause a bubble and make your speedos read funny.

I'll snap a picture one the driveway dries out from the rain... Hoooray rain.

81nautique wrote: That dropped valve seat screams overheat so make sure you check the cooling system before running the new motor. Also how do the spark plugs look, are the electrodes disintigrated or intact? Another cause of extreme damaging heat is low fuel pressure and the FCC being missing points to a problem there. High rpms (full throttle) and low fuel pressure can melt a GT40 pretty quickly. Sounds like you probably won't reuse the heads but just for forensic measures put a straight edge across the valve stems(rocker end) and see if they are all the same height. Extreme heat will get those valves so hot they will Tulip into the head, you'll think the valves are all different lengths.

Well, the spark plugs were MIA so I can't check those sadly. As far as the cooling system I'm going to replace pretty much everything as I don't want to put together a motor and skimp on keeping it cool. From the way this boat appears i would guess it has a ton of hours. The gauge decided to work last night and showed 536 hours but, they were replaced at some point. So, pretty much anything that could be considered a wear item will be replaced.   As far as the heads I'd like to reuse them if possible but rebuilt. I need to get them to a machine shop to see if they are salvageable.

81nautique wrote: Just a heads up, Your machine shop is probably well aware of this but overheated small block Ford heads are known to crack between the valves. Might be hard to see in this photo but it's there.

I'm sure they are but won't hurt to mention. I hope the heads and block can be re-used.

PS,   I love that your son is into the fixing :)    mine has about a 15 min attention span for mechanical things... I keep trying, but so far, it's a long process

After searching and unless I'm missing something if this head is salvageable I would certainly save $$$ rebuilding these verse buying a reconditioned set from somewhere. I found a post on here that has a few different vendors for the "p" heads that run around 500-600 for a set plus shipping.

A long block with GT40 or GT40p heads gets to be pricey typically so it might be cheaper to get your block fixed up and put a set of gt40ps on it or get a small block and put a set of gt40ps on it. Don't pay the money for gt40s new or rebuilt as they are no better than the 40ps and are more expensive, don't buy a stock long block unless you are really tight on the budget you will miss the 45 ish hp on that new of a boat and it will effect resale if you cant get it to one foot speeds

Joe, your thoughts this. Say you needed another block for a lefty, would it be worth while to source s late model 351 out of a truck so to take advantage of the roller block?

If the block # above starter is F47TE it will accept roller lifters.

First off, I'd be very careful about changing too much on the induction side (heads, cam) on a gt40 as the ECM is not capable of making tune variation based on different (better performing) components. P heads are a proven deg upgrade over gt40 heads but i probably wouldn't push it much beyond that in terms of flow or cr improvements.

That said, I am now with joe on the roller cam bandwagon- they're awesome. They improve both peak power and widen the powerband, and improve reliability (no chance of wiping a lobe). Tune issues as denoted above notwithstanding, the only downside is cost, which is primarily a concern on RH engines as the blanks are custom. LH roller stuff is readily available and relatively inexpensive. You can always run tie bar lifters in a non-roller block and skip the retainer entirely- this is a nice, albeit expensive ($400-500) upgrade. Or you can have a non roller block machined to accept the retainer. Either way, I'd go roller on anything I wanted to improve performance on if it can be squeezed into the budget. HIGHLY recommended, even for moderate builds. Roller rockers would be much lower down on my list of wants and are much easier to add later. Of course, this is coming from a guy who has wiped a flat tappet cam and has seen the performance difference a roller delivers. FWIW.

Eddie, is your 383 roller? I can't remember.

TRBenj wrote: First off, I'd be very careful about changing too much on the induction side (heads, cam) on a gt40 as the ECM is not capable of making tune variation based on different (better performing) components.

Tim, just curious, but are their any third party companies that make some sort of ECM that could be used that is re-programmable or let you set up a custom map. Undoubtedly the effort to build up the map for a marine application from scratch would be monumental, the obvious preference would be to start with a known good map from PCM and modify from there. Again, realizing I could get off my butt and do the research myself, but I just wondered if anybody has ever looked into it.

It's interesting, for mod-ing out my snowmobile, There are a couple of devices that go between the ECM and fuel injectors, that let you modify the map to fine tune your performance. We do all the same things on that side, bigger intake, bigger pistons, higher compression heads, better flowing exhaust. Obviously with every modification, you need to adjust the fuel map. The same technology exists for outboards. Just seems like there would be similar products/solutions for auto/marine application

The reason I ask about a roller engine is simple. Someday my Shamrock will need a re power. Late model 302's should still be a dime a dozen and even 351 rollers were used in trucks. Why bother finding and using a flat tappet motor might as well up grade. They use a lefty which makes it easy too. Might just start looking soon.

That guy that built his own EFI 351s for his Bayliner here used megasquirt. Apparently the PCM stuff is all locked up. You can't even see the programming let alone modify it. jbear and Orlando76 will take it from here.