Jump to content
Sign in to follow this  
oldtuckunder

One for Peter Cobbold, Sharks Teeth now Hammer Head Shark

Recommended Posts

Here's a picture that Peter might like, I'd previously posted a picture of Sharks Teeth inlet diffusers I'd found in a UK TR8 inlet manifold of obscure origins, when low an behold this weekend I received a box of TR8 bits from the States that contained the following inlet diffusers. Sure looks like the factory were playing with a few designs to aid fuel atomisation on the TR8's.

@PeterC 

Alan

5ad3d7ee5cc30_ebay04008(Large).thumb.jpg.5a2dde789db0debb8b83ac0acebd5576.jpg

Share this post


Link to post
Share on other sites

Are those so that an injector jet hits the plate in the inlet?   Easier to implement  than higher pressure, but inelegant!

JOhn

Share this post


Link to post
Share on other sites

Hi John

No these are for Carbs, they fit between the carb and the manifold past the throttle plate, and are supposed to help break the air fuel mixture into smaller droplets and help prevent wall wetting and pooling.

Below is a Sharks Tooth variant that I found on what may have been a UK development TR8 manifold.

Alan

5ad46ed680893_sharkstooth4(Custom).thumb.jpg.e41137efbc81c8beff6330320143305c.jpg 

Share this post


Link to post
Share on other sites

Ah!  Now I see why "Shark's Tooth"!

I would have thought those were more for dealing with wall wetting, by launching pooled fuel into the air stream.  No idea why the angled plate, unless that was supposed to direct the flow at the lower side of the duct to drive fuel into the flow.

But they are awfully like the many snake-oil "Fuel economy" devices that charlatans sell, like "vortex geneartors", along with pellets in the fuel or magnets or "fuel ionizers"!     Were all production TR8s carburettor driven?    And all sold to the USA, which by that time was getting emissions regulations?     Did Triumph fit these, or are they aftermarket devices , like the charlatans' products?

fuel economy vortex generator.jpg

Here's a really good example of such a product, the FuelShark -showing how totally useless it is!

AND, a video of a charlatan selling them!

John

Edited by JohnD

Share this post


Link to post
Share on other sites

'Fuel deflector rings' are mentioned in H P Lenz's book,on Mixture Formation in SI Engiens, with a diagram very similar to those sharks teeth.

He also reports streams of liquid fuel wetting the wall downstream of the butterfly spindle. So the hammerhead device might be designed to pick those up and fling it into the gas flow.

Defectors often used below twin choke downdraught carbs to try y ensure equal mixtures between cylinders.

Peter

Share this post


Link to post
Share on other sites

American TR8's (we will ignore the approx 30 genuine plus some unknown number of development hack UK ones) were a mix of EFI "Flapper" and Carb versions, all carb versions were Stromberg equipped rather than SU's found on Rover SD1's etc in the UK.

The V8 inlet manifold does a very steep 45 downward bend just after its entry, the spade shaped one above may have been a design to help deflect the airflow down,  what I do now know is that they were standard fitment on the carb'd TR8 part number ERC2741, however that as a part seems to have disappeared off the face of the earth as far as Google is concerned. 

What I suspect is that an amount of factory experimentation was done to try and eradicate some of the problems. Its known that large carbs at low air velocity don't work well, its why fitting 1.75 carbs on a 2 ltr six pot normally causes issues that need some resolving, the 1.75's on a 2ltr really only come into there own at approaching 6K and above rpm, below that the 1.5's have some advantages.

Alan

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×