Researching LAT Tri-Y headers

[ojxxx]

I'm fixing to make a set of 180 degree headers for a Mk1 and I'd like to read up on them before I get started, the owner has a set of what appears to be original castings with 'Tiger' cast into them and I'd like to see how they were originally configured etc and how the piping was laid out for them.
I'd appreciate any leads to articles, original pics, history etc.
thanks, Oj

 

[ojxxx]

From what little I see, they are not 180deg but Tri Y which should simplify construction but would like to read about them.

 

[michael-king]

CAT were looking into making some downpipes for the Tri-Y LAT headers a year ago.. Do a search for that...should be some photos of them.

Do you have the modified motor mount for the pass side iirc.

 

[spmdr]

I have not seen 180 degree headers on a Tiger, but I have seen them on a Cobra.

It has been over 50 years ago, the Cobra was CSX 2137, one of the short trunk lid cars.

The primary tubes that crossed over had slip fit connections.

The car had big side pipes, going along the outside of the car.

At that time, to run in the BP class, Cobras could only run a 4 barrel carb.

Webers put the small block Cobra in AP class and transform the sound of the car at idle.

With 180 degree headers, the idle sound is unique also, similar to the sound of Webers.

 

[michael-king]

When you say 180 headers do you mean cross over headers like gt40 where they cross over the heads? Ive seen a muscle car, comaro iirc that had headers that crossed over under the sump... Not much ground clearance

 

[ojxxx]

CAT were looking into making some downpipes for the Tri-Y LAT headers a year ago.. Do a search for that...should be some photos of them.

Do you have the modified motor mount for the pass side iirc.

I am the mech/fabr shop, and, yes, he has different motor mounts as well, I haven't seen them. I wasn't inclined to do the project but when he showed the cast manifolds with the 'Tiger' in them I changed my opinion, they looked authentic as you can get. I'll do the search for the Tri-Y LAT headers, thanks for that.

 

[ojxxx]

When you say 180 headers do you mean cross over headers like gt40 where they cross over the heads? Ive seen a muscle car, comaro iirc that had headers that crossed over under the sump... Not much ground clearance

No, I thought they were but they are, in fact, Tri Y style where 2 ports go into a single tube, then the 2 tubes on each side merge into to form the collector.

 

[spmdr]

In the simplest terms, 180 degree headers connect the outside 2 cylinders of one bank

with the inside 2 cylinders of the other side bank and visa-versa.

so, 1 and 4 with 6 and 7

Then 2 and 3 with 5 and 8.


Tiger exhaust system tech has been a bit behind most other cars,

Because of the intrusive unibody X frame, so it's past time for some change...

 

[spmdr]

With the Tiger Tri-Y manifolds, I would think an X pipe would be a good start. Hmmmmm....

Or is it Gerrrrrrrrrrr ?

 

[Franchi]

Reproductions

 

[ABSunbeams]

Have one side (Passenger) only with the pipes. Currently makes a good wall hanging.

 

[Warren]

Reproductions

John is a member here, will add his username soon. If you want his number in the meantime click on my name and send a conversation.

 

[ojxxx]

The tubes look pretty easy enough to make, I wonder why they were made from so many different pieces? that lower set should be made from 2 pieces, the set with a kick would need a couple extra, it isn't like I've got a mandrel bender to use. I'll make them from stainless and post up some pics.

 

[ojxxx]

I'm almost ready to start on the project, the owner brought the castings so I can make stainless flanges and he also has a set of LAT stainless headers, he's unsure which he wants on the car but leaning to the Tri-Y. Here's the castings:

I looked for a date code, all I saw was 'S126'; 'S114' & an 'S29' adjacent to the 'Tiger' (you can see the numbers after the 'R' on that silver set), the 4th set had nothing.
Anybody know the significance of these numbers?
Thanks, Oj

 

[hottigr]

Interesting...I just got a set of tri-y's out of the attic for a friend and the numbers on the tri-y's were a different sequence.

 

[ojxxx]

I've finally gotten started on this project, I've pulled the existing exhaust, the motor mounts etc and have this block mocked up for fitting. The drivers' side looks like it'll clear but the passenger side has interference with the motor mount and a new one has to be made.

I have made a new one and its mocked up for final fit in the car, I'll get some photos of it when I pull everything back apart to do the mockup on this plastic block. I machined some .3125 thick stainless to make the flanges from and ready to order up the tubing to make the headers from.

 

[Warren]

Side by side of the difference between the hangers

 

[ojxxx]

Thanks for the photo, I could only use the 2 holes bolting the chassis mount, the header itself protruded into the boss for the 3rd bolt. Heres what the chassismount looks like, I had to do some additional clearancing on it since the photo was taken, its still in 'raw' form, I'll add gussets to it after everything is fitted.

 

[Theorangetiger]

I'm wondering if when you have the motor mount and chassis mount bolted on like that, they sit in the same position as they would in the car with the weight of the engine on them and flexing of the motor mounts. I believe the LAT chassis mount was modified more for clearance of the down-tube than clearance of the manifold itself.
Can you get a measurement from the outside of the chassis mount to the outside of the one on the other side and compare it to the dimension between the frame rails where they bolt in? I think it's possible it might be pulled in a little in your photo.

 

[ojxxx]

Here's how the tubes look, the chassis mount is bolted up to the motor mount. In the car they are different and not as tight as it looks.