View Full Version : TR4/4A Any Webbers or Dellorto out there on a TR4 ?

08-06-2004, 11:52 AM
hi there, people again i do need lots of help. i finally installed the J-TYPE overdrive on my TR4A (I intend to share pics) and now im dealing with the installation of my dellorto carbs on my TR4A. i paid more then $350.00 for my intake manifolds cannon and the linkage sys ... and now the surprise that the linkage does not fit to the accelerator pedal, and its originally for a 1500 tr and mgb.

does anyone out there have pics of a set of webber carbs installed on a TR4 or TR6 please let me know.


Paul Vernon - Guatemala, Central America /ubbthreads/images/graemlins/driving.gif

08-06-2004, 02:39 PM
I have a diagram of Weber installation on a TR4 from TWM induction. It shows the top of the installation. I can photo the top and underside of my setup also. The installation uses the lever assembly mounted on the firewall. However the bellcrank to actuate the carbs mounts on the rear intake manifold with the the linkage going between the carbs. You may find air cleaner clearance a bit tight. I used an ITG filter I had in my shop and cut a new aluminum plate for it. I removed the Webers last year; they were not flexible enough for the type of driving I do. I live at 3400' drive to about 10,000. and am taking the car through Yellowstone park and to the midwest later this summer. I loved the concept of an accelerator pump; lots of fun off the line and out of the corners at autocrosses.

08-07-2004, 11:58 AM
you dont know how much i appreciate your help, the pictures you sent have been so helpfull, so you always keep a set of extra carbs cause the handle better the changes in altitudes ??

greetings and i again i thank you ...

paul vernon

Mark Beiser
08-07-2004, 12:32 PM
Just out of curiosity, what are you planning on doing with the car?

If you have a stock, or mild performance engine, you are better off with SU carbs.
With Webber carbs, even correctly set up by an experienced tuner, you loose a good bit of your low and mid range torque. You need your power and torque in the low and mid RPM ranges for normal street driving, and autocross driving.

Even with a very high performance built engine, a set of larger modified SU carbs will come close to matching the top end performance of the webber carbs, but still maintain some drivability at lower RPMs.

Now if your building a race car, all that goes out the window. Properly set up webbers will give you more top end power, and definatly look the part. /ubbthreads/images/graemlins/wink.gif

08-09-2004, 11:52 AM
For the most part I have to agree with Mark Beiser's assesment. I do not remember loosing the low and midrange torque he mentions. This could be because my engine is "heated" up a bit or the amount of money I spent on the installation obscured honest appraisal. Part of my problem was the lack of a local expert and the cost of the parts necessary to do the job correctly. I inherited the local box of Weber parts, however, sometimes to save money a previous user had bored out the jets without obscuring the number, more fun. With info received on this forum after posting my problems with the webers, I removed them and spend more time driving the car then messing with it. The Roger Williams book "How to Improve Triumph TR2-4A" has chapter devoted to SU vs Weber. Also check this site https://www.cruzers.com/~twakeman/TR/index.html for an excellent discussion on tuning Webers for a TR.

08-10-2004, 01:38 PM
well ... i upgrated the engine with 87mm pistons - 2200 cc?, a mild street camshaft, oversize valves that mossmotors sells, heathers and a double exhaust systems, to improve performance, i actually posted a topic on this forum called webber vrs. dellorto, and because dellorto was preffered by people here, i bought them in italy. i already overhauled the carbs, and bought the manual, for them.

well see how i do, the good think is that i have people here that i think can help me,but please, any help will be very much appreciated.

thank you ... paul.

Mark Beiser
08-10-2004, 11:04 PM
Well, sure sounds like you have an engine that actually needs those carbs! LBC's with engines like that are always fun, just its a pain in stop and go trafic if you have a cam that has a power band starting at >3000 RPM. /ubbthreads/images/graemlins/cool.gif

Simon TR4a
08-12-2004, 10:55 AM
Hi Paul, I have a modified TR4a with 1.75 inch SUs and am very happy with its performance up to 5500rpm, though I expect a pair of 40 dcoe would help the bottom end.
I also have recently bought a 79 Spitfire which has a single 40 dcoe but no other mods, I am aware of-this does not seem a good match.
With the webers I think it is important to get the correct size venturi, main jets and air correction jets because there is litle or no adjustment on the carb. Being used to the SUs I find the range of adjustments useful and the carbvery good for road and track use.
My cars specs:
86mm pistons (stock size)
9.75:1 compression
Larger valves, intake and exhaust, head mods to reduce shrouding.
Bigger ports, header, free-flow 2.5 inch exhaust.
Kent Supersprint cam, lightweight lifters, chrome moly pushrods. (This cam is the "Sprint 88" cam in Triumphtune.)
Electric fuel pump, Holley pressure regulator, oil cooler etc. Simon.