Falls flat in 4th

[rbucklin]

New engine, 1600DP, new 34 pict-3, all new bits (distributor, wires, coil) engine starts, idles great, has good acceleration in 1st-3rd but falls flat in 4th. Does not stumble sputter or cough, just nothing there. Carb is clean, accel pump works great. Timing set idle 7.5 before tdc, full advance at 30 before tdc.

Thoughts?

[Jimbug57]

Try a larger main jet. If you live around sea level you probably want a 120 or a 125 or meby even a 130 - don't know, buy one of each. You could pull it out of the float bowl check the size. If it's a 115 that is probably the issue. It's working on the 2 jets on the other side of the carb until around 3000 rpm, so sounds like you have those dialed in.


Also check for vacuum leaks. Better yet, go to Harbor Freight and get a $14 vacuum guage.


Those are my first couple ideas anyway - Jim
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[rbucklin]

Thanks Jim, just went through the vacuum leak gremlins and resealed everything. Doing the carb cleaner method. No engine fire so far. Just went through everything again, timing set to 7.5/32 and advances smoothly. Also went through tuning air/fuel and bypass again, got idling better and seems happier. Test drive next then will check main jet size. Thanks for advice.

[vwracerdave]

Let me guess..."Freeway Flyer"
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[oprn]

More like a freeway butt dragger don't you think?

My Buggy came with the late model higher final drive and yes the 1600DP was sluggish in high gear but it would still hit 85 mph with some patience. "Nothing there" is a little bit vague. Do you mean you have to shift back into 3rd gear to drive it or is it just slower in 4th?

[rbucklin]

Actually not sure about the trans. It was in the car when I bought it. I doubt it's a flyer though, it started life as a rail for off road then the FG body was added later.

What I mean is, it will gain speed in first three gears, fourth it will maintain some speed (60 or less) on level ground, gain speed slowly on a downslope and lose speed on any upslope.

[gt1953]

What distributor are using with the new 34 pict-3.
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[Bama Dave]

Was the rear tire size mentioned? If not, is it stock?
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David Richerson

1970 Beetle
1971 Super
1972 Baja

[rbucklin]

Distributor is a new, Kuhltech 034 electronic w vacuum advance. Rear tires a 27 in tal, a bit above stock. I have the same tire height and wheels on my other one and they're not a problem. I do sort of suspect the distributor as the problem but I'm not going to start buying and swapping distributors in and out. My dune runner has the 34 pict-3 with Kuhltech 010 centrifugal and it's running pretty good.

[vwracerdave]

If you car runs fine in 1-2-3 and falls on it's face in 4th it is not a distributor problem.


Your little 1600 does not have enough horsepower to pull the taller tires and probably what I'm guessing is a "Freeway Flyer" transaxle. I would barrow a smaller set of rear tires from somebody and take a drive.

Another problem you might be having is the accelerator cable is not adjusted correctly and the carb butterfly is not opening all the way to a wide open throttle position.
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2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[dawie]

Rbucklin wrote:
"It started life as a rail for off road then the FG body was added later."
What type of fibreglass body does it have, (square edged un-aerodynamic, maybe?)

[oprn]

It would have to be a fiberglass clone of a Bus to have that much wind resistance!

It does sound like your engine is down on power. That's about what I would expect out of a 1200 40 hp engine with the taller late model gears. The tires are not helping either.

Time to dig in and give it a full blown tune up starting with valve lash adjustment and compression test.

My Buggy did better than that in 4th with a 1600DP but it did have dual Kadrons (maybe 4 hp more?) and 24" rear tires. If you came out of 3rd at 3000 rpm and into 4th it would struggle to gain but if you held on to 3rd to 4000 rpm then it was ok. And yes it pulled down on the hills. That's with what racerdave calls the freeway flyer gears. A term I understand that was given to the late model stock transaxle gearing by some enterprising company to enhance sales.

Hope that helps.

[[email protected]]

The 2 prime suspects are

fuel restriction (clogged filter, tank outlet, bad fuel pump)
or
too much ignition timing

Those are the first item to cross off the list.
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[rbucklin]

Body:

I really don't believe it to be a freeway flyer trans, though I have no way to know for certain. Given the low level of work that had been done on the car to start with, I just don't see the previous owner spending the money.

Yes, tires are a little taller than stock, but not enough, I think, for this much effect on a new engine's performance, based on my previous experiences with VW. Throttle cable adjustment is something I hadn't thought to double check. I'm pretty certain that when I installed it it was opening fully.

Yesterday I had the car trailered down to the shop that built the engine. They're looking at it today so we'll see what they come up with.

[rbucklin]

Well crap. Just talked to the shop. They say it has a flyer trans. I can't believe someone would put one of those in a rail built for offroad. It just makes no sense whatsoever to me. Although, given the idiotic way the thing was originally built I guess I shouldn't be surprised. My apologies to all you who came up with that right away. The good side of this I guess is, I appear to be getting pretty good at setting up and tuning engines. Time to start shopping for a good trans. Anyone here in Phoenix?

[Max Welton]

Arizona Transaxle comes to mind.

Max
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[mcmscott]

Just change 4th gear, you dont need another trans.
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[oprn]

Yes! That was what I was going to do after I upgraded to a 1911cc engine. Now I don't need to as the new engine has no problem with the higher gearing.

[Bama Dave]

...or run shorter rear tires....
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David Richerson

1970 Beetle
1971 Super
1972 Baja

[rbucklin]

Well, engine is fully sorted Believe it or don't, put in a 009 and all problems disappeared. No flat spot, quick, and pulls in fourth even with the tall 4th gear. Still bought a new trans. $600 for a fully rebuilt from Don's BusBox here in Peoria AZ.

In the end, I just don't trust the old box internals so at $600 and a couple hours work it's just worth it to remove the concern. Next, steering...

Thanks Y'all.