TR6 Weber 45 MCHH conversion for TR6

[Coyote1]

I may be stepping into something but I am wondering what the feelings are about the Weber 45 MCHH conversion for a TR6. Diehards seem to think that Strombergs and SUs are the only carbs that should be used. However, this Weber kit seems to be getting fairly good reviews as a replacement option.
I have only found a few reviews but overall they are positive. One discussed them being used as part of a TR6 performance upgrade project with increased power over Strombergs based on Dyno readings and 0-60 times.
At any rate, I'm about to pull the trigger on a set of these but would appreciate your input.

Larry

 

[martx-5]

The Weber 45MCHH carb was originally designed for use on Harleys. It has migrated to other areas of use. It's sorta like a half a DCOE. My question is how many carbs are you putting on, two or three? And, how much HP does the conversion actually make? Have you seen the dyno readings?

My personal opinion is that engine work such as compression increases and cams will yield much more impressive HP figures then bolting on some expensive carbs.

If you just want want to upgrade the carbs, I would opt for a set of triple Strombergs. Just my opinion.

Edit: I see the kit has two carbs Weber 45MCHH Carbs

 

[Marvin Gruber]

I have a couple of webbers. Didn't like them. They make the car go like a bat but for around town driving they were too rich. Couldn't ever get them set right. I like SU's for the 6.

Marv

 

[martx-5]

I have a couple of webbers. Didn't like them. They make the car go like a bat but for around town driving they were too rich. Couldn't ever get them set right. I like SU's for the 6.

Marv

If you have the DGVs, they are very problematical on TR6's and I feel not worth messing with. <span style="font-weight: bold">Properly set up</span> DCOEs are fine but not worth putting on unless you have had a mess of other engine work done.

For my money, nothing beats the SUs for everything but all out racing.

 

[Coyote1]

This is a link to the project car I mentioned.


https://classicmotorsports.net/articles/six-pack/

 

[Darrell_Walker]

Good article, and if you read carefully, you will see that they admit the stock carbs needed rebuilding. They could have rebuilt them, and done the same tuning, and probably got about the same results.

But $400 for the conversion kit may be cheaper than a quality rebuild.

 

[TR3TR6]

I have two webber downdrafts on my 76 TR6 and have had no issues with them. I use a manual choke and only need it when the car has been sitting for several weeks and not started. Performance wise, it's like trying to compare apples and oranges. The webbers ready push it. You might want to do some shopping around, I picked the webbers up off of ebay slightly used for $200.

 

[Coyote1]

Well, this may all be for not. I talked to the vendor and he says they have not been able to get them over the last few months. Seems like Spain is having some financial problems which is effecting Weber. I did ask him about the carbs and he says that they have had very good reports from those who bought them. Most installed, adjusted and ran them with no problem.

 

[kodanja]

I have Webber DGV on my 69 TR6, I have not had any issues with then, I re-jetted them last year & they perform perfectly....

 

[Lonestar245]

Sorry if this has been addressed more recently, but this thread seems to be at the top of the list when searching for Weber 45 MCHH info, and happens to be for my car- a 1972 TR6.

I recently purchased this car, and it has two Weber 45 MCHH carbs. As attested here, it goes like mad when you want it to, but everyday driving is kind of miserable, not to mention fuel mileage is horrible and it is obviously tuned far too rich. My plugs are sooted up badly due to being too rich. The other evening, with the sun behind me, I could see the foggy cloud of fumes produced as I accelerated away briskly after a stop.

So my question is, is there any opportunity to re-tune these carbs, to lean them out? I confess I am totally unfamiliar with Webers, but I have read elsewhere the jets a common to the DCOE's, so maybe there is hope?

I do have a pair of Zenith Strombergs that came with the car and they are currently being rebuilt. Knowing how ZS carbs work, I can see how they might be superior for the TR6 engine under almost any circumstances except on an engine that is built and used for racing. They more or less tune themselves based on engine demand.

Photo of my engine bay attached.

 

[andrewcheesman]

Hey Lonestar - I am in a very similar situation. Have you made any headway?

My '70 TR6 has the GP3 cam and a pair of these MCHH's hanging off the side - it pulls pretty strong, but it leaves a cloud of gasoline everywhere it goes (and all over me, and whoever's riding shotgun, and passersby...). In my case, it's so bad that the engine wants to stall if you let it sit at idle long enough without blipping the gas.

Have had the carbs tuned by an LBC expert who was able to make some improvement but not completely remove the issue. PO installed some sort of pressure regulator - it's from Holley, perhaps this one, although it's unclear what pressure level it's gauged for or how it's been calibrated - so my next hypothesis to test is that the pressure coming in is just too high.

No good pics at the moment, but can post if helpful to any on the forum

 

[Madflyer]

My 73 TR6 has the Stromberg's ( 2 ) some have said SU work better. In the threads above it is how you drive and cam and such. as to pressure Web's need a pressure reg. and low even pressure. maybe even an elect fuel pump. I see you live in California and can run at any number of elevations Web's do not like that. Adding a Stromberg may be a better option for coastal driving. Keep asking questions and find your comfort zone. I am in the Reno area and a TR 6 friend has trip Webbers will go fast but not in town MF

 

[Simmo]

I have 3 DCOE 40's on my TR6 which has also had a lot of engine work done. They are very good but sure chew the Gas.

 

[Lonestar245]

Hey Lonestar - I am in a very similar situation. Have you made any headway?

My '70 TR6 has the GP3 cam and a pair of these MCHH's hanging off the side - it pulls pretty strong, but it leaves a cloud of gasoline everywhere it goes (and all over me, and whoever's riding shotgun, and passersby...). In my case, it's so bad that the engine wants to stall if you let it sit at idle long enough without blipping the gas.

Have had the carbs tuned by an LBC expert who was able to make some improvement but not completely remove the issue. PO installed some sort of pressure regulator - it's from Holley, perhaps this one, although it's unclear what pressure level it's gauged for or how it's been calibrated - so my next hypothesis to test is that the pressure coming in is just too high.

No good pics at the moment, but can post if helpful to any on the forum

I also have the Holly PR. It would not go less than 2.5 or 3psi. I found this video on how to solve that problem and I did the work and yes, I can dial it back. I have it running at 1.5psi, but it did not solve my problem.

 

[Lonestar245]

Hey Lonestar - I am in a very similar situation. Have you made any headway?

My '70 TR6 has the GP3 cam and a pair of these MCHH's hanging off the side - it pulls pretty strong, but it leaves a cloud of gasoline everywhere it goes (and all over me, and whoever's riding shotgun, and passersby...). In my case, it's so bad that the engine wants to stall if you let it sit at idle long enough without blipping the gas.

Have had the carbs tuned by an LBC expert who was able to make some improvement but not completely remove the issue. PO installed some sort of pressure regulator - it's from Holley, perhaps this one, although it's unclear what pressure level it's gauged for or how it's been calibrated - so my next hypothesis to test is that the pressure coming in is just too high.

No good pics at the moment, but can post if helpful to any on the forum

I did this, but it did not solve the problem of running rich.

 

[billspohn]

I am surprised that no one has done up a triple carb SU set up for these engines and sold them. You get a straight shot into the cylinders and increase power as well as mileage.

Given the capacity of each cylinder, you'd probably be fine with triple HS4 carbs derived from 1 1/2 MGBs

This is a manifold that I created for triple 1 3/4 SUs on an MGC - tested to 130 mph+ - worked beautifully!

A sharp eye might be able to guess the source of the basic manifold bits - TR 4A, machined and heliarced together. Part of a conversion that took the engine from probably 130 bhp (don't believe the higher factory claims) to about 175 bhp.