old distributor onto newer A4?

[Marty Levenson]

Hello,

I recently bought a newer, rebuilt A4. It came with the Delco distributor with points. All the parts look pretty new.

A few years ago I upgraded our old A4's Prestolite distributor to electronic ignition. Can I swap my old Presolite into the new A4? The tie down clamp is different, and the holes don't appear to line up and are different sizes. How can I modify the tie down system?

I am a bit ambivalent about swapping - see the value of fixable points over the black box of electronic - but I know our old distributor is reliable, and the Indigo electronic system has been perfect since day one. The Delco is an unknown. Also, I have all the old "guts" and spare points for our Prestolite, so I could revert to points as a fix if needed when cruising.

Thanks,
Marty 1967 Tartan 27 Poseidon

[jpian0923]

The prestolite distributor does offer better alternator belt clearance. My understanding is that you can swap the two out but the hold down clamp is different.

If you look at this page http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=OVAD&keywords=all&template=Templates/B000_storebuilder.html you can see the difference between late and early accessory drives. Looks like early accessory drive has a screw hole for smaller prestolite distributor hold down clamp and the late drive doesn't. To me it looks like you can drill and tap for the proper screw to fit the early prestolite. Or, you can swap out accessory drives.

[Dave Neptune]

Marty, there are advantages to the Delco which have been stated above. You have the Indigo so why not dust off the Delco and install the Indigo. The attaching parts are basically the same and you could get an instalation kit from Indigo. I'm pretty sure Tom sells them with his parts available for the ignition.
Modifying the hold down is no biggie and you may find one at MMI, Indigo or even on this forum.

Dave Neptune:cool:

[edwardc]

The prestolite distributor does offer better alternator belt clearance. My understanding is that you can swap the two out but the hold down clamp is different.

If you look at this page http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=OVAD&keywords=all&template=Templates/B000_storebuilder.html you can see the difference between late and early accessory drives. Looks like early accessory drive has a screw hole for smaller prestolite distributor hold down clamp and the late drive doesn't. To me it looks like you can drill and tap for the proper screw to fit the early prestolite. Or, you can swap out accessory drives.

Based on my experiences, the early model engines had the tapped distributor hold-down hole in the accessory drive housing, while the late model engines have it in the accessory drive flange that is part of the block casting. I know this because at one point, I had an early model block that had been built up as a short block with all late model parts, including the accessory drive. When I went to mount the distributor, there was NO hold-down hole!

I ended up drilling and tapping the block's accessory drive flange myself. Hardest part was to get the tap started cleanly. Once started, it cut easily. A rag carefully stuffed on the inside of the flange caught all the drill and tap shavings.

[Marty Levenson]

Hey All,

Thanks for your replies.

I think I'll change plans for now, and use the Delco distributor that came with the engine.

We have 2 A4's at the moment. My long term plan is to (hopefully) rebuild our 1967 A4 next winter, and I'll just have the reverse problem fitting the Delco onto it then if I switch.

Our original 1967 A4 was running fine before the water jacket inspection plate sprung a leak. When I pulled the starter and generator to have a look at the problem I was shocked by the amount of rust. Chipped away a bit and .25 inch thick pieces popped off. That, combined with 44 years of RWC (though the water passages look good) and significant blow-by (well masked by the Indigo scavenger, but still....?) and a rat's nest of wiring added up to my decision to pull the engine. We cruise a lot in The Gulf Islands and Desolation Sound, which means lots of motoring...so I want reliability as much as possible.

When this rebuilt late model A4 popped up on Craigslist I decided to get her and repaint (as it was a mediocre job done in 2009) and use the new A4 in our Tartan 27. I hope to rebuild and sell the 1967 A4 if the block is workable.

Thanks,
Marty