EMPI reproduction 30PICT-1 Carburetor - An in-depth review

[glutamodo]

Review: EMPI 30PICT-1 reproduction carburetor.

Short version– The currently produced EMPI 30PICT-1 reproduction carburetor is manufactured with an error that allows too much vacuum to the distributor for proper timing when using it with vacuum-only distributors. After many tests, comparisons and observations I learned the cause was, they put the advance drilling that is down by the throttle plate just slightly too low in the carb body (compared to the butterfly.) “Ovalling” that hole so it presents more surface area above the butterfly, plus slightly enlarging the bore of the upper advance fitting will fix this – or at least it did so on the two carbs I was lent to test on.

(thanks Charlie - Jody '71 and Keith - keifernet for loaning me their EMPI carbs to test and experiment with, and to Brian Vrba -VRBA's Parts in Fort Collins, CO for the German 30PICT-1)

Hopefully this is of some use for someone. I put that "abstract" summary in because you really don't need all this info, but I had compiled it, taken the pictures, etc. So here it is for those who are interested in it.

I'm posting this in the Beetle Forum. When I did that in-depth test review/comparison post about the H30/31PICT carb a couple of years ago that went into the Late/Model Super Forum, as that was a clone of early 70s carbs. This one is of a clone of the 1967-only 30PICT-1 carburetor.

Introduction:

When I first heard about this carburetor, I thought, and posted here more than once, how could they mess this up? Today’s EMPI company has an unfortunately well-earned reputation for making and/or distributing some the worst quality VW parts around. Their parts are usually cheap, but you get what you pay for. In this case, the carb was not cheap, but comparable to other brands of new carbs. But, the 30PICT-1 (and, outside the US, the 28PICT-2) were the last Solex carbs produced before VW started to tweak the carburetor for emissions. So it is a very simple design – and the question remains, how hard would this be to mess up? At 170 dollars or more, you’d think it had better be good! I’ve mentioned here a few times in the past that was I needing a new carb, I’d go with this EMPI 30PICT-1 over a Brosol H30/31 or the other carbs out there right now. (well, I’d actually try to find a good used or rebuilt Mexican or German 30PICT-1 before buying anything new though)

Well, reports of poor running with the EMPI carb started to show up. Since I’ve done previous testing and comparisons between different Solex carbs – mostly to determine just how the Brosol H30/31 carb was setup compared to other Solexes – I offered to check out some of these EMPI units. Well, I’ve done so now and here are my results.

Overview of the EMPI 30PICT-1 carb:

The fit and finish of the EMPI carb appeared to be good. It does have kind of an odd shine to its metal though. The throttle shaft bushings are nice and tight. The only poor thing I saw was the threads for the idle speed adjustment screw on the throttle arm – the threads are poorly drilled and are inferior to German and Bocar versions of this carb – it’s like they used a worn out tap to make the threads.. But that wouldn’t affect the running problems I was looking for. Examining the carb in and out, it appears to be nearly identical to the Mexican Bocar Solex 30PICT-1 and the German Solex PICT-1 carbs.

One thing, this carb has "EMPI" stamped all over it. I don't mean that it's cheesy all around , but they actually went and stamped or etched the EMPI name and logo everywhere on this thing!

The China stamp - no surprise there.

The 1385cc “40HP” engine on my 1962 ragtop was to be the testbed for this.. It's got 1965 heads, 1.1:1 rockers, everything else is pretty much stock, including the "fat boy" 40HP distributor.

For comparison testing, I gathered together some other carbs. A 28PICT-2, which is NOT a variant of the 30PICT-2, rather it is a 28PICT-1 that has a later style throttle return spring. It was introduced in other countries after late 1966 when VW changed the pedal cluster and throttle cable setup, and it not seen in the US very often. I scored a quite decent used one at a swap meet earlier last year. Which I equipped with the jets out of my “spare” 28PICT carb (145y air correction, 120main, 55pilot) I also got a good used 1967 (105-1 base flange number) 30PICT-1 to test. Also the used Mexican Bocar 30PICT-1 currently on this engine, plus an NOS BOCAR 30PICT-1 that I got off eBay a couple years ago - (it was/is NOS but had some water damage to it when I got it, so some of the pics might not look as pristine as you might expect) Plus, of course, the new EMPI 30PICT-1, from "Jodi '71".

Thanks to keifernet, several weeks later I got a 2nd slightly used EMPI carb for further tests and comparisons.

Here are pictures of the candidates for my initial comparisons:

NEW EMPI 30PICT-1:

NOS BOCAR 30PICT-1:

Good Used BOCAR 30PICT-1

Good Used German 28PICT-2:

Good Used German 30PICT-1 (1967 version):

Before I stop talking about fit and finish, one thing I noticed in examining them, is that EMPI is using a solid metal pin for the fast idle cam travel limiter. That was what Solex used on the original. However Bocar used a roll pin - a small one, but personally I think the roll pin is a better idea. Solex went to roll pins on the 34PICT carbs, a larger roll pin than this admittedly, but they did use it. Since those pins are a known weak spot on the 28 and 30 PICT carbs, I think having a roll pin that is exerting some internal pressure on the hole that it is pressed into is a better setup and would be more reliable. Maybe not, but I've never seen one fail on a BOCAR carb.

At the time, I also took comparison pictures of the lower advance drilling of the various carbs. I made a mistake though, I should have removed the throttle arm screw to completely close the butterfly - the problem would have been much more apparant had I done so. In the pictures they don't look that far off, really. But, as you'll see further down, they are! ( http://members.trainorders.com/android/VW08/EMPIreview/5-ThrottlePlateCompare.jpg )

Okay, onto Testing:

I've done tests of carbs before, using just a general purpose fuel pressure and vacuum gauge.

It works, but such cheap gauges don't usually read anything below about 40mmHg vacuum. It's OK for SVDA and DVDA carbs which have larger vacuum pulls, but I decided it was not suitable for the tests I wanted to make. Consequently, I looked on eBay and got a much nicer (and much larger!) vacuum test gauge.

I tried running the first EMPI carb as I got it. Which had with a 125 main jet (they come with 120, the owner of the carb had changed it) , 55 pilot jet, and an air correction jet stamped with 115. 115?? That is tiny, smaller than any such a/c jet I’ve seen on a 30PICT carb. And I don't think it really is 115. Look at this comparison picture - that "115" looks to me like it's bigger than the 125y.

The carb seemed to run pretty rich, black smoke at idle. Not surprising, as I’ve found that at my ~ 4850 foot elevation you need it running leaner for the thin air. So I went down to a 120 main jet, and it ran quite a bit better and was more of a match for the 1385cc engine. The pilot jets were stamped the same size. However the specific jetting is not the focus of this investigation, the vacuum advance signal is. All I cared was to get it so it would run OK enough to test the vacuum signal. Which I did.

I checked all of these carbs on the engine in my 62. All of them ran OK as they were, except the EMPI. I did the aforementioned jet swapping, and eventually got it to sort of idle OK, but the idle mixture screw wasn’t acting that great. But I got it to go after a bit. I logged the RPMs per every 10mmHG vacuum pull with my vacuum gauge T'd in the line going to the distributor.

Results:

On this chart are plotted the RPMS that the vacuum pull in mmHg would be attained. This is with the 40HP ZV/PAU4R5 distributor connected.
Idle speed for me is approximately 900RPM. I did the tests for this over several months - I had to wait a while beore I got my 2nd test carb from keifernet. Then the winter weather hit, plus the holidays, which delayed me from making and testing various modifications. The last two columns represent the final results after all of the modifications were done. (I did start to log some "in progess" results but thought was really too much information, so I just stuck with the final results)

Now, what does this mean?

The 30PICT-1 was factory matched to the “205K” distributor. That particular distributor is at total advance at approx 65mmHg. Thus, on the chart the RPM given at 70mmHg would be at which engine speed the distributor was totally advanced. (Now, 40HP distributors get to total advance at lower vacuum pulls, more like 45-50mmHg.) On all three used carbs, That 205K spec of 70mmHg was seen between 2700-3400RPM, which would be a pretty good place for it. On the NOS Bocar this happens much sooner, at 1900 RPM. That is a bit too quick, but still usable. And that will change as the carb wears and gets some play in the throttle shaft bushings - requiring higher RPMs for to achieve that RPM. However on the new EMPI, this occurs in the 900-1100 RPM range, which is not usable at all. When the advance comes in that fast, the RPMs shoot up accordingly, so a decent idle speed is going to be about impossible to set, trying to balance that advancement against the idle speed adjustment. And with full advance at all times, there is not going to be any kind of proper throttle response. Unless, of course, if you have the idle speed set around 550 RPM, which is too slow (regardless of what the VW owner’s manuals used to say in the early 60s), and any variation that brings up the idle speed will make it advance, and the advance will bring up the idle speed – making it about impossible to set an idle speed. So as this carb was set up, it was not usable. The 2nd EMPI carb I got from keifernet and tested later on, it had better numbers, 1400-1600 RPM for get to up to vacuum pull for full advance, better, but still too low.

Why do both of these new carbs have so much vacuum pull at low RPMs? One reason is tight throttle shaft bushings. All of the
used carbs tested had moderately, but not excessively, worn throttle shaft bushings. So, in evaluating the EMPIs, the best comparison probably comes between the NOS Bocar and the two new EMPIs. (and to see the difference between tight and not-so-tight throttle bushings is to compare the two Bocars - My used one has at least 5 years of use by myself and it was used when I got it, so it’s worn, but it still runs good. )

However, the big question is - Why does the new EMPI vary so much from the NOS Bocar unit? One possibility would be that the upper advance fitting into the venturi was blocked off or restricted. I pulled the vacuum fitting out of the carb and checked this, and it was open. It did look a little smaller than other carbs were though.

The way these vacuum-only-advance carbs work, is the vacuum advance signal is a balance of two vacuum sources in the venturi – a fitting high in the venturi across from the port where you hook the advance hose up to. (pre-PICT-1 carbs only had a drilling there, no fitting), And then there is a drilling that leads down to the base flange, goes through the base flange and is sealed off by the base gasket, and goes to a drilling that is partially blocked off by a closed throttle butterfly. (Later SVDA and DVDA carbs do not even have an upper fitting, they are designed for an entirely different vacuum curve and response, based on a much stronger vacuum signal that falls off under lighter loads at higher RPMS.)

Those are the initial tested and visual comparisons.

Further Tests, Observations and Modifications:

The EMPI carb was, as is, unusable if mated to a vacuum-only distributor. The reason(s) for this, and possible solutions to the problem of the excessive vacuum issue came down to these:

1. Give the throttle shaft bushings some wear. Hah! Well that’s the reason you buy or rebuild a carb, so that’s not an option.

2. Alter the lower advance drilling.

3. Alter the upper advance fitting.

Upon inspection, It looked to me like the upper advance fitting was just slightly smaller on the EMPI than on the other units. So, I enlarged it on the first EMPI carb I had. It did help “a little” but not enough. I enlarged it further – to around 11/128”, but there was still way too much vacuum at too low of RPM. (That size is probably a bit too big, I think if I did it again I'd go 5/64ths.)

So the next step was to check into the lower drillings as well. Here are pictures of what I found:

AHA! As you can see, the NOS BOCAR carb and the other used ones all had that lower drilling almost completely blocked off by the butterfly. But the EMPI one, it's got like almost half of the drilling exposed! This is what I should have seen earlier on.

So how to deal with it? I wasn't going to try to fill in the hole and redrill it, that's beyond my capabilies. However one thing I could do is alter that hole a bit. To do this I got out the same Dremel tool and some micro drill bits that I'd used to enlarge the upper advance fitting. I then proceeded to reshape the opening of the lower drilling as best I could without dismantling the carb entirely. I dug into it slightly, and aimed it so there was more surface area above butterfly exposed to it when it was almost shut. I didn't take a picture of the first carb I modded, but here's how it looked on the 2nd one. Keep in mind, the picture shown just above here of this carb was taken after this modification. You can't even see my mod with the butterfly completely shut, I left the lower half of that hole alone, just reworking the upper half:

The results of the two mods worked. If you look at the chart above, you'll the first carb’s numbers got much better – and it drove a lot better as well. Since the second carb wasn’t as bad, I tried not to make the modifications as severe as the first carb. However the results showed I might have gone too far. The vacuum pull dropped further than I intended, similar to the numbers on my used test carbs. I will say this though, it drove just fine though, I think I liked how it ran slightly better than the first one did, but that could also be a result of different ambient conditions.

One last thing remained for me to do in this – an extended test drive more than just bopping around town. Since it’s the middle of winter and I live in the middle of Wyoming, I was waiting for weather conditions to be decent for such a drive. They haven’t been. This final step has delayed me posting this report until now. However the last couple of days I decided to brave the winter drive it a few hundred miles. I put 600 miles on this modded carb and it drove just like my normal BOCAR 30PICT-1.

( I then tried that 28PICT-2 out.......but that's a different PITA story entirely. )

Andy T.

[weinerbug]

Wow! Awesome writeup and explanations.

I have never thought about carbs to this degree. I am just happy when they work. Now if something isn't working on my 30 PICT 1, I'll understand what to look at.

Thanks

[johnanddes]

Great job Andy. Really in depth and now I know not to buy a EMPI 30 PICT-1 (unless I need parts for my German rebuilt(thanks Keifernet))
_________________
John

1969 documented numbers matching bug
1968 F250


Keepin the ISS from colliding with space junk

[glutamodo]

I don't know if I'd recommend not to buy it. With those relatively simple modifications, the carb runs very well. Also, if you use it with a centrifugal-only distributor you don't even have to worry about any of this stuff. ( I know that CIP1's writeup of the carb has their normal "don't use it with an 009" disclaimer - but that's just them covering their butts. Heck I should have dug up my old German 009 and tried it with this carb, I'm sure it would be just fine on my single-port 40HP. It's the dual ports that mostly have 009 problems. ) I'd just as soon left that modded one on my bug if keifernet didn't want his back! It's not a bad carb. If I was keeping it I'd probably play with the jetting some more though.

One last word, if I had to buy a new carb. And had to choose between a new Brosol H30/31 PICT, and the EMPI 30PICT-1, I'd definately pick the EMPI and make the mods to it.

[johnanddes]

Can you give specific instructions on how to modify the carb? Like drill or dremel speed, technique, etc.
_________________
John

1969 documented numbers matching bug
1968 F250


Keepin the ISS from colliding with space junk

[glutamodo]

[visibleink]

Great write up and work. Luckily my original carb cleaned up nice and is running great after a rebuild.
_________________
Been on the samba so long I remember petting that dog to see VWs, WYHI, and green bug girl.

<-- Helga, she slammed her dub in '53 and adjusted valves with her teeth

[Jody '71]

Great Work Andy!!!!!!!!
_________________
'66 Beetle
2011 Hyundai Elantra Touring

[Glenn]

I'm sure glad Keith is rebuilding the good old German ones.
_________________
Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

Member #1009

#BlueSquare

[jonnypink]

Very enlightening!! Just what I was looking for!!

Thank you.

[glutamodo]

I thought I'd add another note or two... I got a PM from someone who said he just put a restriction in the hose from the carb to the distributor to reduce the vacuum. That's something that might work to some extent, however, the vacuum will continue to "trickle" through that restriction and still build up at the distributor. I don't really consider that a reliable solution.

In doing the tests above, there were a lot of other things I did that I didn't talk about - the report was long enough as it was. One thing I did try was tapping the fitting where the vacuum hose connects way into the carb - to almost block off the vacuum drilling that comes up from the bottom of the carb. That sort of worked, but I found the running was erratic - it seemed to change a bit as the engine temperature changed. I didn't consider that a viable fix either.

[jonnypink]

This carb works great with an 009 mechanical advance. You do need the elctromagnetic cut off to keep it from desiling.

[glutamodo]

[Russ Wolfe]

[Russ Wolfe]

[Russ Wolfe]

Just ran across this while rebuilding a 30 PICT-1. 113 129 023S
Vacumm drilling is completely covered when the throttle is closed.
Base numbers are, VW 75-1, and B 6 157.
This carb does NOT have a power jet.

_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

[ALL-IN]

I know I'm way late on this topic, and I'd like to show my appreciation for the information on this forum...

Quick question on the topic of Carbs, currently running a 12OOCC 40HP 6V engine in my 62 bug, I received a consult from a mechanic who suggested I get a new carb instead of trying to rebuit my current one (not sure why), anyway, I've been trying to reasearch a replacement for the current Solex 28 PICT-1. Any suggestions and or website links???

Thanks.

[keifernet]

[snj]

[glutamodo]

The 28PICT-1 is better though, it's got the bigger choke that can later be upgraded to 12V and the better choke pulloff diaphram setup. Of course, you can just put that carb's top on an earlier body. I ran one that way for well over 10 years.