90 Sport cruiser

[Windy Bay]

I got this 1990 sportcruiser 2 years ago. I drove down from Oregon to Newport Beach to pick it up. I sold my 1981 24 open last year, so I am having to get this done so I can fish this year. So far I have built a new engine (383 stroker 430HP 420 ft lb of torque, replaced the lower on my outdrive, took off the 1.95 and replaced it with a 1.78 gear ratio. This is the lower they use on the 454's. Purchased all new Simrad electronics nss evo3s auto pilot radar and 12 inch screen new VHF radio and nema 2000 back bone.. Installed a new thru hull transducer, and removed all the crap that was hanging off the stern. I have about 35 different screw holes that I am having to patch and re coat after patching. I've had to re plumb the water tank for the galley, new side panels, new wash down pump, new bilge pump, new fish hold pump, hydraulic steering, and things I can't think of right now. My holes in the stern are pictured. I have drilled out all the holes to 1/4 inch then used a counter sink bit to enlarge the top of the hole then sanded around the holes. My plan is to use 1/4 inch dowling coated with resign inserted into holes, leaving room for some peanut butter consistency resign, sand and gel coat, with top coat. I have watched hours of youtube videos and I think this should be an ok way to do this. I also had 2 1 inch holes that I am going to use the same method. I have also ordered all new striping.

 

[tbev]

Looking good, I can see how much work you've done already. First thing I recommend, especially if it's a new motor you want to run a closed loop cooling system. It looks like you have a heat exchanger but I can't really tell. You defiantly want to run clean water in the motor.
Second is that your method sounds pretty good for patching holes but you absolutely need to put a piece or two of glass matt over the hole not just peanut butter. I've patched many holes that way and the dowel and the resin shrink over a year or two and will come loose if there is no glass mat over the top. after you dish it and plug it cut a couple progressively larger round pieces of mat to level off the hole, prolly three or four, then fair and gelcoat. If you don't the worse thing is they will fall out the best case is you'll get halos around the patch where the shrinkage is creating a void.

My trim tab screws, the ones along the tab leaked and rotted a lot of the transom behind the tabs. You may want to pull those screws out and reapply 5200, just a suggestion.

Can you give me some details on your AP setup? I can see your running a standard GM styled Power steering pump, are you running an electronic hydraulic pump for the AP as well or are you using that for your AP as well?

 

[Windy Bay]

First thing I recommend, especially if it's a new motor you want to run a closed loop cooling system

I have a half system, one of the things I am concerned will it have a large enough capacity.

Second is that your method sounds pretty good for patching holes but you absolutely need to put a piece or two of glass matt over the hole

I have considered this, but will have to sand a larger area around each hole. I was thinking of using glass cloth.

Can you give me some details on your AP setup? I can see your running a standard GM styled Power steering pump, are you running an electronic hydraulic pump for the AP as well or are you using that for your AP as well?

Everything is simrad. I left the standard power assist in place, I considered removing it, but decided to see how I like it with the power assist.

 

[tbev]

I have a half system, one of the things I am concerned will it have a large enough capacity.

I have considered this, but will have to sand a larger area around each hole. I was thinking of using glass cloth.

Everything is simrad. I left the standard power assist in place, I considered removing it, but decided to see how I like it with the power assist.

What do you mean by a half system? The way I set mine up is like this..
Seawater runs through the "dirty" side of the system and coolant circulates in the "clean" side, it's pumped by the water pump on the motor but never exits the system.
Coolant circulates thru the motor, water pump on motor, heat exchanger (s) and that's it, I I use a restrictor plate in the thermostat housing to regulate operating temp. I have a very small hole because I have two exchangers for coolant so my motor runs too cold otherwise. I think you'd probably be fine with one exchanger my size, I ran a 350 on one that was pretty stock I just added a second in case when I built a new slightly bigger more power motor but it's not that much bigger than yours.
I have two exchangers for coolant, one for power steering which is my hydraulic steering system and one for motor oil which is probably unnecessary. Coolant circulates in one direction thru all these components.

Seawater comes in from the drive, sucked in by bravo pump which is a belt driven water pump and goes thru the "dirty" sides of all those exchangers and enters each exhaust manifold where it fills and exits into the exhaust and exits the boat thru the transom. (thru transom exhaust is great as well but it's loud, may not be your thing but it's free hp and mileage.)

I recommend sanding back/tapering a little bigger area, like a 2in round area and adding glass cloth for sure.

 

[Windy Bay]

So the difference between a half system and a full system. A half system only cools block and heads. A full system cools block, heads, and exhaust manifolds. On my system seawater enters thru the leg, goes thru a power steering cooler (only cools fluid in the power assist) then up to the sea water pump, which is driven directly from the crank shaft, thru the heat exchanger and exhausts thru the exhaust manifolds. On a full system the exhaust manifolds are included in the coolant portion of the system, and the raw water exhausts thru the riser. This makes it so you don't have to replace manifolds every few years, you only need to replace the risers. this is the best diagram I know of: https://www.cpperformance.com/t-marine-closed-cooling-systems.aspx

 

[Windy Bay]

"You could also back tape and fill with a resin, chopped glass and microballoon mix and you’d have zero wood involved. But that’ll work either way."

Most of the holes do not go all the way thru. Thus I had to either fill with epoxy, or fill with dowels. I opted for the dowels because I could make sure that I filled most of the hole.

 

[Windy Bay]

Major progress on patching holes and gel coat. got the gel coat from shur fab in Ontario, and they did an awesome job with the color match. It is hard to tell in these pictures, because the pva is still covering the new gel coat. Just sprayed yesterday. Waiting for it to cure! A total of 43 holes and other assorted chips and scrapes.

 

[TheWesNMads]

How did you blend the new gel coat into the old? Did you feather edge sand around your repairs and give the gun a little wrist action to mist it on the edges?

 

[Windy Bay]

The stern was really easy. There is a ridge on the stern, and I just taped off at the ridge, and sprayed most of the transom. The smaller portions were just taped off. when the gel coat cures I will wet sand. The new gel coat is a VERY close match to the color of the boat, and I think it will blend in once it is wet sanded. I highly recommend shurfab color matching service. I believe that is why the color is so close. I'll get more pics when the gel coat is cured and sanded.

 

[brianv20]

You get it wet and please report back to us on the idle quality of that new power plant.
I would love to push more out of my 383, just don't want to run 91 and don't want it to be too sloppy at idle.
I always had a soft spot for the sport cruiser, would be a lot better for my overnights.

 

[Windy Bay]

I am super excited. wet sanding new gel coat and the match is near perfect. before and after pics

 

[Windy Bay]

Getting my electronics installed, and found I needed a new switch panel. I found my horn wires just loose in the overhead, and no where to connect them, and I wanted an auto pilot switch. So I removed the 3 switch in the overhead and replaced it with a 4 switch