Inlet manifold

[twice]

Hi does anyone know where I can buy a triple su inlet manifold ? Just like the look and fancy one .

Don't need carbs got plenty of them .

thanks Terry

[Ragtag]

The only supplier I am aware of is Good Parts in USA.

 

http://www.goodparts.com/shop/index.php?categoryID=2

 

There may be a UK importer but they don't come up on Google!

[RogerH]

Hi Terry,

there is an interesting thread on the Club TRiumph forum suggesting that triple SU manifold is a no no.

The front and rear carb work as expected but the centre carb is almost impossible to set up correctly.

 

They suggest as the 6 cylinder can be looked at as a pair of three cylinders then two SU's work the best.

 

Roger

[Andy Moltu]

It's something to do with the firing order, the triple SU has a certain curiosity factor, it isn't as well balanced as the twin set up.

Tripple Weber/Dellortos effectively have 3 pairs of inlets so 1 choke per cylinder like the PI.

 

I think this issue is also the explanation as to why some of the tubular manifolds don't work as well as they ought.

 

The solution is to fit the modified crank with the correct firing order, but these are quite hard to find.

[DRD]

Hi does anyone know where I can buy a triple su inlet manifold ? Just like the look and fancy one .

Don't need carbs got plenty of them .

thanks Terry

 

Someone's selling one on ebay, although they seem to think its an exhaust manifiold.

 

https://www.ebay.co.uk/itm/Triumph-Tr6-Exhaust-Manifold/332638424322?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

[Ragtag]

 

Someone's selling one on ebay, although they seem to think its an exhaust manifiold.

 

https://www.ebay.co.uk/itm/Triumph-Tr6-Exhaust-Manifold/332638424322?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

 

If buying off ebay you would need to know which engine it came from as there are two versions to cope with the different port spacing.

[stuart]

 

If buying off ebay you would need to know which engine it came from as there are two versions to cope with the different port spacing.

As that one on Ebay has separate paired runners it probably wouldnt matter just adjust link pipes and throttle links to suit.

Stuart.

[TriumphV8]

Friend of mine had the triple with SU HIF44

until I infected him with Megasquirt.

 

In my opinion this warning against these manifolds

is simply from GT who did not know what he was doing.

Being theoretically always prepared to tell anybody its nonsense

he simply did not bring these things together.

He did a lot of grinding and welding in some former pictures what

seems to be the real problem because the manifolds are not bad.

 

The three manifold set runs wonderfull, performance between PI and SU

what means it was noticeable better than the twin SU and the Strombergs

which had to go much earlier. This is a report from somebody who really

did see and feel that swap. That makes a real difference!

 

So its more a question how to do that to bring it to work

instead if it is possible that there is a performance increase.

 

With no doubt there is an uneven process of suction from cylinder

3 and 4 while the others perform symmetric. In practice that had

no bad effect to be felt.

 

Austin did so on some Healeys and you can be sure, they tested

before they made some of the big Heleay with three carbs.

 

So its me who could see such a car perform quite well

and Austin Healey who did that with success.

 

That should answer the question about problems with that set.

 

Richard Good offers two sets of the manifolds for both inlet spacings.

That is a special chance for those who suffer from that narrow head manifold

that is really bad and robs power on a mildly tuned engine.

[Ragtag]

As that one on Ebay has separate paired runners it probably wouldnt matter just adjust link pipes and throttle links to suit.

Stuart.

 

You may be right, Stuart. I have no personal experience, just going on the basis that Goodparts supply two versions due to the different port spacing/dimensions.

[MJF]

I thought the TR250 and early carb TR6 heads had narrower spaced inlet ports, so you really want an inlet manifold to match the head?

[YankeeTR5]

Yes, you need to. A mismatch between an early North American head and later intake manifold (or vice versa) will result in the ports of the manifold offset from the head by about 1/2 inch - something that cannot be easily made up for. Your performance will be dismal especially the higher you rev. Bought a TR250 about 10 years ago from a fellow who had the car in the UK (his dad was foreign service and the family had brought it to the UK when they were stationed there) and had a TR5 head installed. He could never figure why couldn't "get it to run right". Swapped out intakes and the car ran great.

[Andy Moltu]

It's one of the truly bizarre things Triumph did in having some heads with different port spacings with no apparent sound reason for it as not all USA spec cars had this head so can't have been an essential modification over the UK spec heads (in terms of port spacing rather than CR)

[stuart]

It's one of the truly bizarre things Triumph did in having some heads with different port spacings with no apparent sound reason for it as not all USA spec cars had this head so can't have been an essential modification over the UK spec heads (in terms of port spacing rather than CR)

Originally done to prevent fitment of PI which wouldnt pass emissions in most US states.

Stuart.

[Andy Moltu]

Thanks for that snippet Stuart.

 

Would have thought it an expensive way of stopping someone fitting PI in the States!

 

No wonder BL went down the pan.