Indigo Crankcase Ventilation Kit

[Bob.Griffin]

I already sent an inquiry to Indigo but thought I'd also check with the A4 community experts as well.
I purchased the Indigo kit and installed it last weekend, and it seems to work, although I havn’t tested it on a long engine run yet. However, there was one problem encountered during the installation. The spacer plate did not properly match up with either the carburetor flange or the inlet manifold. I tried to use the 2 replacement studs supplied with the kit but couldn’t get them both to fit due to an alignment problem of about a 1/16 inch difference between the carb, spacer plate and manifold (spacer plate is slightly smaller). When I ordered the kit I did indicate that I have an early model carburetor (cast iron with the ‘Zenith’ name running vertically down the main barrel, plus adjustable main jet) that someone before me installed on a late model engine (oil filler above the flywheel casing and on the manifold side). They also went to the trouble of installing the scavenge tube on this carb which runs from the bottom of the carb on the flame arrestor side, up to the inlet manifold. I’m wondering if there was a slight difference between flanges on both early and late carbs. Anyway, I temporarily fixed by using a smaller diameter nut and bolt instead of one of the supplied studs. I would obviously like to fix this by using both proper studs, any thoughts from anyone?

[Bob.Griffin]

Don, I'm hoping you can comment on this anomoly. I just got a response from Tom at Indigo who can't understand why the spacer plate doesn't fit since it's the same for both early and late model carbs. Either the plate isn't to spec or I somehow have a hybrid carb and inlet manifold, both are unlikely. Tom suggested I use 2 x 1/4 inch nuts/bolts, which I probably will, but it's still a mystery.

[Don Moyer]

Bob,

Sorry, but I can't solve the mystery. We've installed many Indigo Electronics crankcase ventilation kits on both early and late model engines, and we're not aware of any difference in the dimensions of the carburetor to manifold flanges. For what it's worth, I measure a nominal 2.25" center to center on the carburetor/manifold flange bolt spacing.

Don Moyer

[Bob.Griffin]

Tom also indicated it was 2.25 inches between centres. I will check this coming weekend.

[tenders]

"Centres?" What are you...Canadian or something?

(Not that there's anything wrong with that. I'm 1/4 Quebecois myself.)

Maybe you have a Stevedore rather than an Atomic Four? Seems to me I recall reading somewhere the difference is some sort of a restriction in the carb limiting the engine to 25 HP to avoid triggering a Canadian import tax or prohibition.....?

[msmith10]

Not a Stevedore problem

I don't know about Bob Griffin's problem, but I do know that it's not a Stevedore problem. The Stevedore used the same carb. There was a steel ring which was pressed inside the intake manifold which narrowed the diameter of the intake above the carburetor. The carb itself was the same as a regular A4.

[Bob.Griffin]

Canadian and proud of it!

Definitely an A4, late model (1970) but previous owners did make several changes such as installing an early model carb and replumbing the oil pressure switch to combine with the oil pressure sender unit. I plan to check the centers (!) this weekend. All I do know is that when I screw the 2 studs (provided in the crankcase vent kit) into the carb flange, the spacer will not fit over the studs, but the new gaskets do.

[luvmyi36]

[QUOTE=tenders;5939]"Centres?" What are you...Canadian or something?

Now that's funny!!!! About fell out of my chair laughing!

[MikeB.330]

how about using a file to egg out the holes a little bit.
As long as the gasket seals against the manifold is should be fine. In a pinch one time I repaired a broken carb flange with JB weld. I still have that carb as a spare.

[Bob.Griffin]

Don, I was at the boat on the weekend and measured both the spacer plate and carb flange, spacer plate was 2.25 inches between centers (note spelling!!) and the carb flange was 2.375 inches between centers, an 1/8 inch difference. I also confirmed the carb is a Zenith early model but no indication why it does not have the standard 2.25 inches between centers, the mystery remains. I drilled out the spacer plate holes until it fit over the studs and is now working as it should. Thanks for suggestions everyone.