Transom Assembly/Replacement

[Will Fish]

So just when I thought my boat was running to a tee.....BANG!!!! and my connecting rod lets loose off from the bearing and blows threw the side of the block. Not to mention only had 324 hours on her. In any event I need to replace the motor, so if anyone knows of either 250 or 292 inline 6 around NY let me know.

Since the motor is out I want to replace my transom plate, gimbal housing bell housing etc. I'm having trouble identifying what I actually have. The boat is a 1974 21' Scatcraft (only made 3 years before selling the design to Formula so I am told.) I have an alpha 1 gen 1 outdrive, and assuming I have a pre-alpha housing setup. In researching new parts, the only parts I can find is Gen I or Gen II.

A few questions, hopefully some of you may know:

Is there any differences between the pre-alpha and the alpha 1 housings?
Will my lower exhaust tube fit the newer transom plate?
Is there any difference in the hole cut-out on my stern?
Any modifications I need to make? I do not have trim limiters on my existing housing.

 

[Bondo]

Re: Transom Assembly/Replacement

Ayuh,.... Welcome Aboard,....

Is there any differences between the pre-alpha and the alpha 1 housings?

Ya, Lot'sa little 1s.... Newer is better...

Will my lower exhaust tube fit the newer transom plate?

Probably not, but 1 for a 3.0l should be an easy fix....

Is there any difference in the hole cut-out on my stern?

Ya, the Gen.II needs 2 more stud holes at the top of the keyhole...

Any modifications I need to make?

Ya, of course,... There's always little things in refits...

The other Gotcha I can think of is,...
You'll need a newer Chevy patterned flywheel cover for yer rear motor mount spacin'...
They're closer on the newer drives...

 

[etracer68]

Re: Transom Assembly/Replacement

Those inline 6's are work horses, I find it hard to belive a rod bolt (Just) let go. If the motor was running great, with good oil pressure. So did you figure out why it failed?

 

[Will Fish]

Re: Transom Assembly/Replacement

Ayuh,.... Welcome Aboard,....

Ya, Lot'sa little 1s.... Newer is better...

Probably not, but 1 for a 3.0l should be an easy fix....

Ya, the Gen.II needs 2 more stud holes at the top of the keyhole...

Ya, of course,... There's always little things in refits...

The other Gotcha I can think of is,...
You'll need a newer Chevy patterned flywheel cover for yer rear motor mount spacin'...
They're closer on the newer drives...

I guess my question is there a difference in the exhaust pipes? I have seen where they are oval shaped, as well as like an upside down "U".

Also is there a difference in the Pre-Alpha vs. Alpha Gen 1 transom assemblies? I assume I will have to replace the entire setup; inner transom plate, gimbal housing, ring bell, etc, but do not want to have to modify my stern, and obviously, do not want it to leak.

 

[Will Fish]

Re: Transom Assembly/Replacement

Those inline 6's are work horses, I find it hard to belive a rod bolt (Just) let go. If the motor was running great, with good oil pressure. So did you figure out why it failed?

When I took the pan off, the main bearing was in pieces and the connecting rod snapped in half, which went through the side of the block, and the oil pan (which took me forever to find a 'new' oil pan for a 292). It was completely wierd, the motor was running great, good oil pressure, no water in the oil, and not over heating. I was running at 3200 rpms (cruising speed) for about 30 min, so I wasn't pushing her. I had an issue with overheating earlier this year, which ended up being a bad gasket in the drive, under the water pump base which was letting air get into the system and not allowing for perfect water flow. But even though she was running hot, I never let her get past 195 max. I guess it's what I get for taking a friend fishing who says as we are leaving the dock "wow motor sounds great".

 

[Bondo]

Re: Transom Assembly/Replacement

Also is there a difference in the Pre-Alpha vs. Alpha Gen 1 transom assemblies? I assume I will have to replace the entire setup;

Ayuh,.... Yes there are Differences,... I explained some of 'em in my 1st post....
Yes, on the exhaust downpipes...
Yes, on the rear motor mount spacin'...
Yes, an Alpha 1 will fit yer cut-out in the transom...
An Alpha 1, Gen.II will need 2 more holes drilled, up top...

If yer gonna do it,...
Lay 'em side by side, 'n look....

It'd probably easier to rework the motorbox, 'n drop in a 4.3l, complete with it's newer drive....

 

[Will Fish]

Re: Transom Assembly/Replacement

Is the spacing on the flywheel cover different on the pre-alpha to gen 1, or just between pre/gen1 and gen 2? I'm looking to replace what I have with the Gen 1, so I can utilize my existing outdrive as it has completely been redone with less than 10 hours on her, and I have a brand new spare as well. And if I change to the Gen 1, I assume I will have to change the exhaust pipe to match.

I agree a new motor and outdrive package would be much easier, but unfortunately, I do not have the extra cash flow to do such. Therefore, I'm going to keep my antique together with spit and glue for as long as I can. Also, my motor box cannot be widened much, as I have stringers flush to the sidewalls of the bilge. So I am basically forced to keep an inline 6 in her.

I appologize for my ignorance, as I have not bought a replacement housing yet, and want to make sure I know everything I need before I start to purchase parts.

 

[Bondo]

Re: Transom Assembly/Replacement

And if I change to the Gen 1, I assume I will have to change the exhaust pipe to match.

Ayuh,.... That, 'n the Flywheel cover....

They changed with the R, or MR..... still Pre-, but newer than yer's....

Ya need to find a downpipe, 'n the flywheel cover for a 3.0l Alpha 1, of about the same vintage as the parts you have now....

You may also have an alignment issue with the riser to downpipe connection...
There's the straight back version, 'n the off-set version...