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Wed Nov 05, 2025 10:06 am

Bit of an odd question, maybe.

I have dual EMPI HPMX 40's on my bug engine, 1835 cc.
It's running well, I had a lot of learning to do, on how to set them up and tune them, but am happy with them now.

So, recently I scored a pair of Weber IDF 40's for a good price.
They will need a good cleanup, and should then be good to go.

Question is, is it worth the work to replace the HPMX's and install the Webers on my engine ?
Can I expect an improvement of any kind ?

Or do I just keep the Webers for a future engine build ?

Would appreciate any input.

Wed Nov 05, 2025 10:31 am

Your HPMXs are already installed and tuned. Stay with the devil you know.

You might go through the headache and expense of installing and tuning your genuine Webers only to find out some hidden reason why you got them at a good price.

I'd go through them carefully, and put them on the shelf for your next build, or sell them on if you can make it worth your while.

For whatever that might be worth...

Wed Nov 05, 2025 11:35 am

I've had zero mechanical or any other casting problems with my HPMX40. I'm sure there are casting differences compared to real weber carbs. The parts in your "good deal" Webers may not actually be genuine parts anymore. The shafts could be worn out, bearings corroded, loose plates, etc. There's a reason they were a good deal, you just haven't figure out why yet.
You already have the HPMX's tuned and working good, I see no reason to swap them out.
As stated above, I'd clean them up and inspect them real good. Reassemble using fresh seals and gaskets. Then re-sell them for profit. For what its worth. Redline sells complete genuine Weber master over haul kits, that include bearings, plates, shafts, etc. You may get more money for them if they're completely rebuilt using quality parts. Or whoever buys them may not care either way.
Unless you're planning on selling your complete engine for another or selling the car for another. Your current HPMX's will likely be transferred over to the next engine build.
I have a small garage, with little space for parts to sit for years waiting to be used again. I'd rather have the cash personally. That's just me though.

Wed Nov 05, 2025 11:55 am

There is an old saying "if it aint broke dont fix it".....

Besides the HPMX's are probably a improvement over the old IDF's....

Wed Nov 05, 2025 12:13 pm

Quote: Besides the HPMX's are probably a improvement over the old IDF's....

Well when you read through multiple threads here on the samba, you come to think that everything EMPI is junk, and Webers are the solution to all kinds of problems.....

Anyways, I will follow the advice here, keep my HPMX's where they are.
And inspect & clean the Webers, replace whatever parts are necessary, and them keep them for a future engine build.

Wed Nov 05, 2025 1:09 pm

MTT3107 wrote: Quote: Besides the HPMX's are probably a improvement over the old IDF's....

Well when you read through multiple threads here on the samba, you come to think that everything EMPI is junk, and Webers are the solution to all kinds of problems.....

Anyways, I will follow the advice here, keep my HPMX's where they are.
And inspect & clean the Webers, replace whatever parts are necessary, and them keep them for a future engine build.
Funny thing about EMPI parts, some are better than most others.
The HPMX carbs are good, from what I have read.

I bought a set of Gen 1 EMPI 45 D series carbs 8 years ago and they absolutely suck! I will never touch a set of those carbs again in the years I have left in my life.
Sheet metal parts are complete crap as well IMO.

Now if, you want to make an improvement over the HPMX or Weber carbs.
I highly recommend Dellorto carbs of the appropriate size for the engine you have.
I feel Dells are much more refined and better quality all around than the Weber and HPMX carbs ever were designed to be.

Wed Nov 05, 2025 1:10 pm

Since genuine weber parts work on the HPMX carbs. For quality assurance and accuracy I swapped all the internal parts on my HPMX for Weber parts. I'm not sure it made any difference, other than in my own head.

Thu Nov 06, 2025 7:40 pm

IMO, genuine (old) italian webers are good, but will generally need professional help to live up to their full potential--which is no better than the current HPMXs.

spanish webers are hit and miss. they never were as well made as the italian ones. the ones sold through redline in california are not worth metal they are cast from.

this is a hard fact to accept, but HPMXs are better carbs all around. they have addressed some of the pitfalls of webers and eliminated some of the finicky bits--which weber has never done....because they don't need to....because people buy them based on the name cast on the side.[/img]

Thu Nov 06, 2025 9:18 pm

So much depends on the model of Weber you have that it’s impossible to make that blanket statement you are looking for.

Fri Nov 07, 2025 11:59 am

New genuine Redline Webers. 2 sets, 3 seats did this as soon as I tightened the idle screws.......

Sat Nov 08, 2025 6:32 am

Mine are italian.

I have taken them apart, cleaned everything as well as I could with ultrasonic cleaner and carb cleaner. They were DIRTY !

Everything looks ok so far, no play in the throttle shafts, and they move smoothly.

Right now waiting for the carb kit from CB Performance to come in, so I can put them back together.
And will report back then.

Sat Nov 08, 2025 9:02 am

The Spanish Weber certainly a hit and miss as mentioned here, I deal with a lot of them, the old Italian Weber's are much better, I see a lot of those also but they need attention sometimes to make him back to as they were new, the Spanish Weber casting suck, as mentioned here the fuel mixture screw seat breaks through the wall I've seen that enough times, I'm working on repairing one at the moment, hpmx carburetors are kind of Hit and Miss, I have not seen any casting issues so much as the Spain Weber's.
But my preference are the dellorto's, made very well, the casting was never flawed, very solid, I've only ever seen one throttle shaft for worn out and I'm sure it was abused, and that's after seeing I'm sure more than a thousand dellortos.
The Spain Weber's and the hpmx carbs I don't think you're going to see 30 years out of them, but the dellorto's you could probably see a hundred years use of them and still not worn out.

Sat Nov 08, 2025 11:08 am

mcdragracer wrote:
But my preference are the dellorto's, made very well, the casting was never flawed, very solid, I've only ever seen one throttle shaft for worn out and I'm sure it was abused, and that's after seeing I'm sure more than a thousand dellortos.
The Spain Weber's and the hpmx carbs I don't think you're going to see 30 years out of them, but the dellorto's you could probably see a hundred years use of them and still not worn out.

Nice refab there Rick.

I see that carb is a 48 Dell. Would this be the Tri Jet version?
I ask because, I was wondering what those brass tubes are above the carb top(s).

Sat Nov 08, 2025 1:31 pm

[quote="67rustavenger"] mcdragracer wrote:
But my preference are the dellorto's, made very well, the casting was never flawed, very solid, I've only ever seen one throttle shaft for worn out and I'm sure it was abused, and that's after seeing I'm sure more than a thousand dellortos.
The Spain Weber's and the hpmx carbs I don't think you're going to see 30 years out of them, but the dellorto's you could probably see a hundred years use of them and still not worn out.

Nice refab there Rick.

I see that carb is a 48 Dell. Would this be the Tri Jet version?
I ask because, I was wondering what those brass tubes are above the carb top(s).[/quot

Thanks bud!

Yes these are tri jet models, that tube is for the third enrichment circuit, these are probably the rarest of all the Dells, I'm lucky enough to have nine sets of them I've collected amongst others, these ones in particular we're going on to a custom built T4 Jake Raby engine.

I just really prefer the Dells over the other models, they are truly more solid and they just don't wear out anywhere I've dealt with the Weber's and the dellortos for almost 40,
the empi Dell's I have dealt with a few pairs, disassembled completely and dissected them pretty thoroughly and unfortunately I wasn't impressed, I could only tune one of the sets that I worked on probably only about 80% at best, that's probably why you don't see a lot of them out there on engines, although I've heard of some people that have had great luck and I have seen a few sets on engines that seem to run pretty good but they need to work a lot of bugs out on them, not sure if they're going to spend the time to do that.