Manifold Fitting

[rickandlee]

I've searched here for several hours and have not found the answer so I'll ask the question. A new to me, supposedly rebuilt, engine in my project boat is missing a fitting. It appears to need a flange (2 bolt) fitting with 1/2 pipe threads to connect thermostat to manifold hose. All of the pictures I find show the barb to NPT fitting screwing right into the manifold. Is this fitting available or do I need to fabricate one or thread the hole? My first A4 since the internet started and there is a wealth of info here. Thanks in advance.

[sastanley]

R&L, welcome to the forum!

I am wondering if maybe that is an early model manifold? The older ones had a metal crossover tube to get cooling water from the head to the manifold..the late model has a 3/8" NPT coming out of the t-stat fitting, and to another 3/8" NPT fitting into the manifold. Do you have a t-stat housing just out of the field of view on the other side of the head & the spark plugs?

On late model manifolds, the flat flange area is still there, but no threads for a fitting..the barb/etc, screws right in the 3/8" NPT hole.

I have only seen early model engines in pictures, so I am guessing..someone with more experience with both will be along to help. Feel free to take some more wider angle pics too..it helps us see more parts and layouts and stuff.

Additionally, the block looks to be late model (sheetmetal flywheel cover), and I think the edges are more rounded in general on early model cast parts as compared to late model parts.

[joe_db]

Moyer sells the piece you need:

You might ask nice and see if they will sell you just one, you don't need both.

[rickandlee]

R&L, welcome to the forum!

I am wondering if maybe that is an early model manifold? The older ones had a metal crossover tube to get cooling water from the head to the manifold..the late model has a 3/8" NPT coming out of the t-stat fitting, and to another 3/8" NPT fitting into the manifold. Do you have a t-stat housing just out of the field of view on the other side of the head & the spark plugs?

On late model manifolds, the flat flange area is still there, but no threads for a fitting..the barb/etc, screws right in the 3/8" NPT hole.

I have only seen early model engines in pictures, so I am guessing..someone with more experience with both will be along to help. Feel free to take some more wider angle pics too..it helps us see more parts and layouts and stuff.

Additionally, the block looks to be late model (sheetmetal flywheel cover), and I think the edges are more rounded in general on early model cast parts as compared to late model parts.

The block has all indications of being late model. The manifold is possibly early model (all new to me). Here are a couple more pictures showing the T-stat housing. If I could get one of those end fittings joe_db has pictured I would probably be good to go.

[joe_db]

You can - the host of this very site sells them

[rickandlee]

You can - the host of this very site sells them

Thanks Joe. I'll give them a call. $72 for the whole thing and use only a piece is a little spendy for me. I have everything in my shop to make one and I'm retired so I should just get off my lazy a## and do it.

[sastanley]

R&L, when you call the parts line and talk to Ken, he'll hook you up. I agree with Joe you only need the one part to get a hose on the front end of what I think is an early model manifold on an otherwise late model motor (& head).

Ken knows his stuff...give him a call and explain the situation...In your case you need to link the t-stat housing exit with the manifold, and then the other end of the manifold heads off to an anti-siphon loop on its way to the muffler.

[romantic comedy]

why not thread the hole?

[JOHN COOKSON]

Why Didn't Think Of This Before?

why not thread the hole?

I just saw some pictures posted by TIM in another thread.
This is a perfect time to do the THATCH modification on your engine to feed the cooling water into the manifold at it's low end.
Run a tube from the thermostat housing to the lower barb already on the manifold. Thread the upper hole, put a barb in it and run a hose to the exhaust system. Easy peasie

TRUE GRIT

Edit: S\B Why didn't I think of this before. Note to self: Engage brain before typing.

[rickandlee]

why not thread the hole?

I'm going to give Ken a call tomorrow to check on the fitting. If the price is reasonable I'll go that route. If not I'll try threading the hole. The biggest problem is the hole is almost 1/16" too large for a 1/2" pipe thread so the threads won't be very deep. I don't want to up size to 3/4" because of restrictions around the hole. I'm considering epoxying a close nipple into the hole if the threads are suspect or won't hold tight. If this engine runs I will probably change to an indigo thermostat because my current T-stat housing and T-stat are pretty trashed. I just want to know if the engine will run at this point before I start putting money into "this" engine.

I will make the plumbing changes to the Thatch idea also.

Thanks, Rick

[ndutton]

You may want to assess the condition of the manifold. If there is a concern over it's remaining life you may choose to pull the trigger now and replace it with new that has the threaded hole already.

[rickandlee]

You may want to assess the condition of the manifold. If there is a concern over it's remaining life you may choose to pull the trigger now and replace it with new that has the threaded hole already.

Thanks Neil. My wife, Lee, wants to here this engine run before she will give me the credit card. It's in our 1975 $1000 S2 26 Mid (8.0 C) project boat.

[ndutton]

My wife, Lee, wants to here this engine run before she will give me the credit card

Can't argue with that logic.

[joe_db]

Buy brass bar stock. Drill the two mounting holes and one NPT hole. That should get you through the test

[sastanley]

At this stage of life of A4's, most of the boats are project boats! Our wives will help bring Lee around (and there are plenty of ladies that own A-4 powered boats on this forum too!)