Pre alpha transom cut out

[79Glastron]

Does anyone have a pattern for the pre alpha transom cut out? It looks like the alpha cut out is a little bit different.
Thanks!

 

[cr2k]

Re: Pre alpha transom cut out

Not off hand but if you do a search on here you will find a few, I know they are here.

 

[79Glastron]

Re: Pre alpha transom cut out

Not off hand but if you do a search on here you will find a few, I know they are here.

I found some of the alpha cutout, but nothing for the one drive (pre alpha). I know they're a bit different.....
Thanks

 

[Bondo]

Re: Pre alpha transom cut out

I found some of the alpha cutout, but nothing for the one drive (pre alpha). I know they're a bit different.....
Thanks

Ayuh,... ALL of the keyhole cut outs are the same,....
The MC-1 just has a couple less bolt holes drilled...
Find the pattern Don has posted for the new Volvo cut out...
It'll work perfectly for what yer doin'...

 

[Don S]

Re: Pre alpha transom cut out

Since there is no such thing as a "Pre-Alpha", what drive do you have? Year and engine size may help.

 

[79Glastron]

Re: Pre alpha transom cut out

Since there is no such thing as a "Pre-Alpha", what drive do you have? Year and engine size may help.

I did use the wrong word to describe the drive in question. From the serial number tag on the bell housing plate its from 1974, 140 HP Mercruiser. What is the correct name for the drive? Also, I saw someone who had a 1967 Merc drive and was installing an alpha one drive and transom assembly. He had to slightly inlarge the cutout at the bottom and redrill the top two bolt holes, I assumed his would be the same as mine????? Please steer me in the right direction.
Thanks!!!!

 

[Don S]

Re: Pre alpha transom cut out

The only reason you would need the top 2 holes would be for a Gen II transom shield.
Depending on your transom shield SN you may or may not have to cut out the bottom any more. There are serial number breaks, not year or model breaks.

 

[79Glastron]

Re: Pre alpha transom cut out

The only reason you would need the top 2 holes would be for a Gen II transom shield.
Depending on your transom shield SN you may or may not have to cut out the bottom any more. There are serial number breaks, not year or model breaks.

Don

The guy with the `67 was using alpha gen I, the transom shield only had 6 bolts, the top two had to be moved out I believe. These are numbers I could find.
Bell housing ID plate 3771824
Transom shield 55894 That number was located on the lower left side, its below where its cast "mercruiser". Thats the only number I could find on it.

I couldn't read the number on the drive itself because the tag was painted over...... I can post pics if that would help any.
Thanks!

 

[Don S]

Re: Pre alpha transom cut out

Tell you what. Here is a link to the Volvo cutout. Get you some a piece of cheap plywood, lay it out and cut it out. Then see how your gimbal housing fits it. Adjust to fit.
The only other choice is to head to your local Mercruiser dealer and see if they will order you a paper template. Not sure they even have one for the old 1 drives anymore.

http://www.4shared.com/document/tCGrNJY4/SX_Transom_shield_cutout_templ.html?

 

[79Glastron]

Re: Pre alpha transom cut out

Thanks, I'll give that a shot and report back.

 

[fishrdan]

Re: Pre alpha transom cut out

Are you going to use the cork gasket for the M1(?) transom assembly, this will help with the bolt hole spacing, if it's different than the Volvo Template. The gasket alone won't work well since it's not rigid enough to make a good pattern, top is too thin.

I suspect the bottom 4 holes will line up with the Volvo pattern, the next 2 up will be off and you will not use the top 2 holes.

 

[79Glastron]

Re: Pre alpha transom cut out

The cork gasket is still attached to the transom assembly, I was going to get a new gasket when I install it in the boat, I guess the new gaskets are cork??? If the top two holes are off a bit, the gasket will help locate the holes somewhat. I don't know if the holes have to 100% perfect, I know they should be square to the transom. Hopfully I can get the template printed out full scale somehow and make a practice hole this weekend.

 

[fishrdan]

Re: Pre alpha transom cut out

I wonder if a Kinko's copies would be able to print the template out to the correct scale?

I'm thinking, you can align the cork gasket to the Volvo template by the 4 bottom holes, then set the transom assy on, to locate/center the upper 2 holes with the 4 studs protruding from the transom assy,, center, measure, etc, etc. The bottom 2 holes won't help line up the template, until you get it resting flat with the sealing surface.

Here's and idea, cut out a piece of tempered hardboard with the bottom 4 holes located properly, hack out a section where the top 2 holes go, then glue some small pieces with holes drilled in them, to locate the top holes properly on the template.

My thinking, getting a proper template, getting it located correctly on the transom, cutting the keyhole and drilling the stub/bolt holes dead nutz straight, is going to be key to making the engine installation easy. When I had to drill some transom assy stud holes, I glued up some MDF 1 1/2" thick, drilled a series of progressively bigger holes with a drill press to get the holes exactly straight, then clamped the MDF guide block to the transom to get the bolt holes perfectly straight. It took a bit to drill each hole (8-10 bit swaps) but the holes were perfectly straight. Probably a bit anal...................

 

[79Glastron]

Re: Pre alpha transom cut out

I went to my local staples on my lunch and had them print it to scale on 24"x36" engineering paper. I checked it with my caliper and it was dead on. I got two copies for $6. Not too bad in my opinion, I'll check it with my old cork gasket tomorrow and try to cut a test "hole" to see how well it works.

 

[79Glastron]

Re: Pre alpha transom cut out

This morning I made a test hole in a piece of plywood. The bottom four holes match up, but the top are off. The 1 drive transom had the studs just a bit closer together. The key hole could be narrowed about 1/2" on each side. Other than that its pretty close. I think I can make it work.
Thanks!

 

[79Glastron]

Re: Pre alpha transom cut out

I took a few pics of the work yesterday. Comments please.