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It's been a long time coming, But I was finally ready to break in my first time building an air-cooled type 1. I really took my time with this one, measured and checked everything probably a dozen or more times, and did all of the port matching and parts balancing myself.

It started right up, did my 20 min 2200 rpm cam break in, and dropped the oil. The oil looked exactly as it should, with good head temps and oil pressure perfect. The video doesn't show the audible tone very well, but it was definitely LOUD, and sounded mean. I will be doing a final carb tune and drive test this weekend.

Here are my engine build specs:

*2332, 9.8-1 static compression, 7.8 Dynamic compression

*Aluminum case tapped for full flow

*DPR German Forged crank, with full balanced rotating assembly

*Mahle Forged pistons w/graphite coating and H-beam forged rods. All balanced to 1/10 of a gram.

*Dual Weber 48's with port matched manifolds

*Empi L6 stage 3 , 44 x 37.5 ported heads

*Engle FK8 cam with CB Performance Straight Cut gears

*A-1 Performance 1 5/8 sidewinder the "race muffler" shotgun tips

*CB Mega spark ignition

*Rancho Pro Street FF transaxle, with Lightened flywheel and Kennedy stage 2 plate.

I'm hoping she will scoot....

I couldn't figure out how to post a video.

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That is awesome!

Forgive me if you've answered all these questions before, but I'm curious about a few things because I am doing some top end work now:

1. Are the pistons the Mahle Motorsports ones?

2. Did you have a machinist hollow out the heads?

3. I assume you used 1:1 rockers because you have a performance cam?

4. Any expectation of HP and Torque?

5. Are you using the Sidewinder "wide open," or are you reducing sound somehow?

6. Did you consider a Stage 1 clutch?  My engine will be strong too, and a stock clutch slips.  I am planning on a Stage 1 at Pat Downs' suggestion, but I haven't bought it yet.  I could still go to Stage 2.

For reference I have:

Pat Downs built 2332 - stock Vintage Motorcars, except as noted below.

Unknown compression, but I am replacing pistons and going with Mahle Motorsports

Dellorto DLRA 45s with the Panchito manifolds

I will use custom Pat Downs heads -- AA base, VW650 dual springs

1.25:1 rockers - the Vintage Motorcars 2332 has a verrrrrry mild cam, so Pat recommended 1.25 rockers

Same A-1 1 5/8 Sidewinder with dual peashooters

Everything else pretty standard

(I suspect you don't read this, Pat, but, if you do, thanks for all the help!)

Hey @Teammccalla Thank you for reaching out. Disclaimer.I'm by no means a specialist with a vast amount of experience. But I did take a lot of time researching, calculating, and i ultimately wanted an engine that was built to handle far more power than what I'm asking from it. I will plan on a dyno test once its broken in properly. But i'm guessing its probably somewhere around 185-190 hp

1. Are the pistons the Mahle Motorsports ones?Mahle Forged graphite coated pistons/Barrels rings.

2. Did you have a machinist hollow out the heads? The empi gtv-2  L6 heads had alot of machine work done already. I was considering getting them flycut to alter the chamber size a bit to hit my dynamic compression where i wanted to  go with (8-1) with 91 0ctane. But decided that it wasnt worth the hassle for the minimal power gain, since i was close at 7.8-1 Dynamic compression.

3. I assume you used 1:1 rockers because you have a performance cam? The Engle Fk8 is a moderate cam with s lift spec of .534 with the 1.4 ratio rockers. I actually measured a tad more, at .541. The power range is 3000-6500 which should be fun for passing on the freeway.

4. Any expectation of HP and Torque? 185ish. maybe more if i flycut my heads

5. Are you using the Sidewinder "wide open," or are you reducing sound somehow? Im using Tigers "race style" muffler. He does offer a baffle that will decrease the volume a few decibels. But I will see how it goes. At 2000 rpm in my driveway I couldn't yell a conversation with anyone, and a radio inside would be totally worthless. It was rowdy and healthy sounding, and I cant imagine what 6500 will sound like. ha

6. Did you consider a Stage 1 clutch?  My engine will be strong too, and a stock clutch slips.  I am planning on a Stage 1 at Pat Downs' suggestion, but I haven't bought it yet.  I could still go to Stage 2. I did.  I know that a stage one.paired with a copper disc would have more than enough holding power for my motor, and would have a lighter engagement. But, i really like the firm feel of a clutch pedal. I grew up with 60-s muscle cars and manual transmissions. I miss that engagement and solid engagement.

I have a page that I am documenting my build on Instagram. I try to update as much as possible. https://www.instagram.com/diy_356/?hl=en

Let me know if you need anything else.

@Teammccalla posted:


I assume you used 1:1 rockers because you have a performance cam?





Most cams are designed to be used with a specific range of rocker ratio. Some are designed for 1.0 or 1.1/1 and can be spiced up with 1.25 ratio. Some are designed for 1.4/1.5 ratio.

Pat is a VERY smart man, and I'd love to know more about his head program. You know: intake runner volume, flow rate, chamber size and shape, etc. I'll bet Pat has more knowledge of aircooled type1 engines than anyone else these days.

The compression, displacement, rod ratio, cam, rockers, compression ratio, basically everything from the velocity stacks to the exhaust outlet all matters to work together.

Eric, you might want to look at the venturi size in your Weber 48s.  If they are the typical 40mm, they might not be satisfactory for you.  The 40mm vents are typical in 48s because those carbs are intended for much bigger engines.  A 2332 doesn't have the lung capacity to pull enough vacuum to get the 48s with 40mm vents working, unless generally wide-open throttle drag racing at maximum rpm.

In effect, with carbs too big, you can adjust idle (on the idle jets), then gag around miserably until about 5000 when there starts to be enough air acceleration through the vents to functionally pull in the main jets.  Then the engine comes alive.  Really comes alive!

But you don't drive at constant 5000+.  And even just getting to 5000 is miserable.  You have to kind of nurse it up there.  You can't just mash the pedal, or it will fall flat on its face.  Air speed through the vent is too slow to pull fuel, you just get air.

You can get away with the 48s, if you make them act sort of like smaller carbs by dropping in 36mm vents.  You'll visually notice right away that the inside of 40mm vent is flat, and the inside of the 36mm vents are, well, venturi shaped.  2332 (or more specifically each 583 cylinder) pulling through a smaller hole, with developed venturi shape, will accelerate the air faster, and lower in the rpm range.  Normal driving (2000-4000) will be much more enjoyable and can be much "sportier".  You won't notice any meaningful difference at the top end, unless you are drag racing.

Living with 48s is a commitment.  Tuning is touchy.  Tiny adjustments move really big butterflies which make big changes.  You'll probably find idle is best at 1100-1200, again because the butterflies are so big they let in relatively more air volume than smaller carbs when barely cracked open a few thousandths for idle.   More air volume = more air/fuel mixture = more rpm.

Last edited by RS-60 mark
@RS-60 mark posted:

Eric, you might want to look at the venturi size in your Weber 48s.  If they are the typical 40mm, they might not be satisfactory for you.  The 40mm vents are typical in 48s because those carbs are intended for much bigger engines.  A 2332 doesn't have the lung capacity to pull enough vacuum to get the 48s with 40mm vents working, unless generally wide-open throttle drag racing at maximum rpm.

In effect, with carbs too big, you can adjust idle (on the idle jets), then gag around miserably until about 5000 when there starts to be enough air acceleration through the vents to functionally pull in the main jets.  Then the engine comes alive.  Really comes alive!

But you don't drive at constant 5000+.  And even just getting to 5000 is miserable.  You have to kind of nurse it up there.  You can't just mash the pedal, or it will fall flat on its face.  Air speed through the vent is too slow to pull fuel, you just get air.

You can get away with the 48s, if you make them act sort of like smaller carbs by dropping in 36mm vents.  You'll visually notice right away that the inside of 40mm vent is flat, and the inside of the 36mm vents are, well, venturi shaped.  2332 (or more specifically each 583 cylinder) pulling through a smaller hole, with developed venturi shape, will accelerate the air faster, and lower in the rpm range.  Normal driving (2000-4000) will be much more enjoyable and can be much "sportier".  You won't notice any meaningful difference at the top end, unless you are drag racing.

Living with 48s is a commitment.  Tuning is touchy.  Tiny adjustments move really big butterflies which make big changes.  You'll probably find idle is best at 1100-1200, again because the butterflies are so big they let in relatively more air volume than smaller carbs when barely cracked open a few thousandths for idle.   More air volume = more air/fuel mixture = more rpm.

Thank you so much for taking the time and sharing this great information. This was my very first motor build, and I pretty much copied a lot of the parts offered, by some of the popular builder kits. I do know that these carburetors weren’t probably going to be a set it and forget it part of the engine, but knowing this definitely puts me in the right direction when I start to tune it. And what you’re saying totally makes sense. I will look into getting the smaller Venturi’s and start messing with it.

Last edited by Eric N

You've already driven farther on your first engine build than I did on mine.

You won't need to constantly "tune" on the carburetors, as long as you have NO slop in the linkage between them.  Once you get them set, they stay set.  If you have any slop in the linkage, you have no hope of getting them set.

The "trickiness" you probably already found out.  You have to loosen the downlink to make balance adjustments, and then when you tighten it up again the balance isn't quite right. So, you have to do it again, and even though you barely touched it, when you tighten it back up you find you've overshot, under shot, or its worse than before.  That's because the butterflies are so big, even a .001 change in opening will make a big change at idle rpm.  Essentially you are trying to make micrometer-fine adjustments with loosie-goosey threaded downlinks.  When you tighten the locknuts, the slop in the threads tightens up, and maybe 'this time' it lands perfect. 

But once you get it, it will stay there, for 10,000 - 20,000 miles or more, unless you do something to change it.

It can work with the 48s, just choke them down to act more like 44s.  Driving will be much more fun, and at cars-and-coffee you'll win the open-kimono envy:  "Yep, those are 48s".

PS:  I love your dashboard.  Patent it.

@RS-60 mark posted:

You've already driven farther on your first engine build than I did on mine.

You won't need to constantly "tune" on the carburetors, as long as you have NO slop in the linkage between them.  Once you get them set, they stay set.  If you have any slop in the linkage, you have no hope of getting them set.

The "trickiness" you probably already found out.  You have to loosen the downlink to make balance adjustments, and then when you tighten it up again the balance isn't quite right. So, you have to do it again, and even though you barely touched it, when you tighten it back up you find you've overshot, under shot, or its worse than before.  That's because the butterflies are so big, even a .001 change in opening will make a big change at idle rpm.  Essentially you are trying to make micrometer-fine adjustments with loosie-goosey threaded downlinks.  When you tighten the locknuts, the slop in the threads tightens up, and maybe 'this time' it lands perfect.

But once you get it, it will stay there, for 10,000 - 20,000 miles or more, unless you do something to change it.

It can work with the 48s, just choke them down to act more like 44s.  Driving will be much more fun, and at cars-and-coffee you'll win the open-kimono envy:  "Yep, those are 48s".

PS:  I love your dashboard.  Patent it.

Yes. The slop in the linkage arms was driving me nuts! I got a sunburn sitting in the driveway, fiddling around with the loosie, goosy down rods. It would have been better off with a set screw drilled into the end link and do away with those dang lock nuts.  I may look into doing that. If I could do it over again I would have ordered a different fuel pump block off and went with the CSP Linkage. I still may do that later, I'm just focused on getting this done, otherwise ill forever change stuff and never see completion. I did manage to get all of the carbs metered and synced with the snail.

I do have 42 intakes and reading up on the subject, I could definitely go down a size on my venturi's. My cam makes power to 6500, so I will be ordering probably 36/38's, and start from there on my tuning. Do you have any source recommendations for finding these? CB doesn't offer 48idf. venturi's

C n C is my driving force and the only reason I'm building this!

No Doug Fir was harmed during the building process of my dash!

@Eric N posted:

Yes. The slop in the linkage arms was driving me nuts! I got a sunburn sitting in the driveway, fiddling around with the loosie, goosy down rods. It would have been better off with a set screw drilled into the end link and do away with those dang lock nuts.  I may look into doing that. If I could do it over again I would have ordered a different fuel pump block off and went with the CSP Linkage. I still may do that later, I'm just focused on getting this done, otherwise ill forever change stuff and never see completion. I did manage to get all of the carbs metered and synced with the snail.

I do have 42 intakes and reading up on the subject, I could definitely go down a size on my venturi's. My cam makes power to 6500, so I will be ordering probably 36/38's, and start from there on my tuning. Do you have any source recommendations for finding these? CB doesn't offer 48idf. venturi's

C n C is my driving force and the only reason I'm building this!

No Doug Fir was harmed during the building process of my dash!

Gene Berg carburetor linkages are also great quality and possibly the only one you will need to buy.

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