Hello All--another new "clue-less" VW owner HELP !

[BajaBarbie1]

Hello fellow VW folks decided to take up off-roading because my daughter loves it--but I'm having some odd problems I can't solve--there's no VW mechanics where I live. Thought it was time to join a forum and get some advice form the experts. I know enough about the superbeetle 1600 engine to get myself into deep trouble...NADA

We found an old "pink" buggy built around the very early 70's for the Mexican 1000--out in Arizona . We call her "Baja Barbie" My daughter loves it. You can still see some of the old painted logo's coming through layers of paint--Anyone out there remember "MOON" racing logo's? It's actually built very tough--the frame and running gear/clutch transmission R great, old bilsteins--has a bus tranny, and a 1915 engine, new 044 heads.

But I have Engine problems--Spits and cracks a bit at idle--when accelerating immediately hesitates coughs/cracks. #2 and #4 run very lean--no deposits at all on plugs. (Gap at .028 I blieve) #1 and #3 are running rich. Single carb dual intake,--44 EMPI HPMX. I've jetted/rejetted rich/lean until the cows come home. Has heating tubes. Spark is good, valves adjusted. the kid I bought it from tried to get a turbo set up on the 1915--he could never get it to run right--he was trying to blow through an old webber 44--and then it was left to sit for about 5 years. Wondering if engine was so heavily modified for turbo it won't run "normally" I went through it--"uncobbled" all the messes, doing all the basics--cleaning tank, installing a new unmolested single EMPI 44 HPMX carb, low flow fuel pump/reg, fuel filters, I jetted according to EMPI's charts--special attention to high altitude--I'm at 7K feet. Compression is low per cylinder but consistent-90lbs. Maybe I need to start with a fresh rebuild? I have not taken apart the engine...yet. Oil pressure great--22 lbs idle, 60 lbs at 4K RPM. Here's where I'm baffled: since #1 and #2 Share th same intake and 3,4 the same, why the heck is 1,3 rich and 2,4 lean? First thought--I have a vac leak on intake manifold position for #2 and #4 where it bolts to the head. Did the carb cleaner trick spraying where intake meets head (new 044"s--I didn't install them) while engine running--no change/increase in idle. Thought I would remove air intake manifolds and use liberal amounts of gasket sealer and see if that helps.

Thoughts? possibly cam shaft is worn not allowing full opening of #2 and #4 intake valves? Do #2 #4 share the same intake cam lobe? I've thought about measuring the dispalcement of a 'rich" valve closing (the rocker) compared to a lean one--if a lean valve isn't moving enough to open fully--that must be it ?

Ok--I know alot of info--any advice is greatly appreciated !

[Marc]

Your suspicion of the cam as a potential problem is warranted - there are only 4 lobes on an ACVW cam, so opposite cylinders share both intake and exhaust bumps. And a flattened lobe can still have enough lift to function at idle, and not affect the compression test results. Since the carb cleaner trick showed no results, I wouldn't bother with gooping the intakes - make checking out the valve lift your first order of business.

If the previous owner went so far as to build the engine with a low compression ratio for the turbo installation, that (and the altitude) could make the compression test numbers low even if the rings & valves are sealing well...but even so it's going to be hard to tune. He may have simply added some copper-ring head gaskets (there are no gaskets in stock form, the cast-iron cylinders seal directly against the aluminum heads) which could be removed, or replaced with a thinner version, to raise the C.R.
If your tests confirm a flat cam the whole engine has to come apart to change it (no pulling it out the end like in a conventional engine) so you'll have ample opportunity to dial in the appropriate C.R. in the process. Don't be surprised if you need to buy another set of (shorter) pushrods to get the correct rockerarm geometry upon reassembly since odds are you'll be making the engine narrower than it is now, if there's no shop nearby to lend assistance that could set the project back a week or more.

Although it sounds like your symptom is far worse than can be attributed solely to it, another thing to consider is that there is a mixture discrepancy between the cylinders due to the engine's firing order. #2 (or #4) has to initiate the airflow in the manifold, so it's already established when #1 (or #3) takes its turn - then there's a long pause while the other side of the engine fires before the process repeats. Since fuel and air are of different densities, at low speeds this effect can account for some difference in plug readings. Not likely to be the villain in your case, I just bring it up so you'll know to never expect perfectly-matched plug readings with a centermount carb.

[BajaBarbie1]

Thanks Marc for the advice. Much appreciated. Since bringing this thing home I've spent many a weekend "uncobbling" alot of other problems--now its down to getting the engine sorted out. I did the "teaspoon of oil" trick in each cylinder to check for valve leak or ring issues--compression came up to 150 lbs consistent each cylinder. So probably rings/cylinders ? My motorsport background is primarily British cars and bikes of the '50's and 60's. I've always been able to read plugs and tune accordingly--but I was floored when after replacing with new plugs and running Barbie around the block a few times #2 and #4 were completely clean-- and #1 ,#3 were sooty. VW's are a completely new animal to me at this point. I have a feeling this engine will need to be stripped and rebuilt.

I'm looking for a VW mechanic/engine builder in the Flagstaff Arizona area--if anyone out there knows of one let me know

[Marc]

Yeah, if the "wet" test jumped up that much it's safe to assume that the rings are done (or worse). Claims that they are "thick-walled" to the contrary, 94s are actually pretty thin and don't take kindly to overheating...they're only .006" thicker than slip-in 87s which don't have a good reputation when it comes to distortion from heat-cycling. If the pistons aren't scuffed and the cylinders aren't tinged blue you can probably get enough more miles out of them in a play-toy to justify the doing a clean/hone/rering, but if you decide that they need replacement you should be aware of another option that recently came upon the scene - AA (in China - sounds worse than it is, their stuff's not too bad) is now making 92s with the same external dimensions as 94s, so by giving up ~4% displacement you can gain about double the life expectancy.

[Piledriver]

Welcome to the STF!

First rule: Pictures or it didn't happen
(800x600 125kb max, jpeg or png format usually)

...so by giving up ~4% displacement you can gain about double the life expectancy.

You may double the ring seal life expectancy again my changing to real air filters, the common "high performance" gauze air filters pass fine silt (silica AKA glass) like they aren't there. This is the stuff that kills rings and bores. (aside from getting out of round)

Oiled foam filters like Uni Filters are very effective at both airflow and as actual air filters.
IIRC they make a version that wraps around a std gauze air filter and basically uses it as a support frame.
(like outerwears but much thicker)

As Marc noted, the center mount Webers suffer from the "idles on two" issue just like Kadrons (dual singles at the heads)...
Doesn't hurt anything under power, but the Kadrons will have better performance off idle as they don't need manifold heat like the long tube setup. (fuel falls out and pools up in the long, cold tube, working heat risers would help if present)

[BajaBarbie1]

Thanks again gentlemen--this is where you realize what I don't know about VW-
"94's"-- assuming these are 94mm dia cylinders ? (Ok--I can hear everybody laughing out there ) Are the 94's typical for the 1915L capacity ?

Single carb woes--I actually did my research and decided on dual carbs--but duals won't fit inside the frame !

Pistons, rings and cylinders--I'll go for a good quality forged set--any suggestions? At this point I'll have someone that is experienced do the rebuild--If the PO did some odd mod or cobble with specs on the engine--I may not catch it and wind up spending more in the long run.
I have the "Bug Me videos"--rebuilds seem pretty easy--but I don't have the time--

Pics-- will post when I have time--

[Piledriver]

Is there a T1 equivalent to Tunas old T4 intro web page?
(Gave a short basic primer with links to tech tidbits by subject)

Davids stickies at the top of the T1 forum would probably provide many ...weeks of reading material.

[Marc]

Forged pistons aren't required (or desired, for that matter - their requisite looser clearances make a racket until at full operating temp) at the kind of specific HP numbers you'll attain with all but the most radical of conventionally-aspirated Type I motors..."cast" slugs will get the job done just fine for your application - I promise

94mm is the bore required to turn a stock-stroke (85.5x69=>1585) motor into a 1915. 92s bring you to 1835cc with a stock stroke.

I have dual-carb fitment issues on my trike, too - unless I whack up some manifolds to place the carbs further outboard or do major surgery on the frame tubes, I'm stuck with a center-mount carb. Fortunately, the lighter the vehicle the less objectionable the inevitable off-idle hesitation becomes - at 1200 pounds I don't really even need manifold heat. In an off-road car that's probably not being driven too much when it's cold & damp out, a 2-bbl (with preheat) shouldn't be too hard to live with - when you know what to expect from it, you can anticipate and adapt somewhat. A bigger/sooner accelerator pump shot (by increasing the stroke and/or the size of the nozzle) is often all that's needed, but it wastes fuel and can end up diluting the oil so don't go hog-wild, just fudge it up enough to be tolerable.

[Ol'fogasaurus]

Lee

[Piledriver]

Note the the engine is currently a 1915 with worn out 94s at the moment, so the thickwall 92s are the only other current option.
(Thickwall 92s are drop-in replacements for std 94s)

[Ol'fogasaurus]

"... the kid I bought it from tried to get a turbo set up on the 1915"... "

Sorry, I read this post over several times before I posted then several times again after 'pile's post before I saw this and other obvious notations.

Lee

[BajaBarbie1]

Thanks for all the info--much appreciated. Will check out as much info on this site as i have time for--right now I'm just trying to triage the engine and decide on a rebuild.

It's got 044 heads--really nice ones-German made, so I'm thinking the last build was probably a decent one.

Anyone heard of "Air cooleds Only" in Prescott Arizona ? Are they good? I'm going to have them do the rebuild--

[Jim Ed]

This site has nearly a whole aircooled vw manual:
http://vw-resource.com/

[aussiebug]

This site has nearly a whole aircooled vw manual:
http://vw-resource.com/

But hardly anything on "big bore" stuff Jim - Dave and I like stock or almost stock, so most of the info is on that.

Marc, Piledriver and others have much more experience with large capacity/higher power than we do.

[Fiatdude]

Anyone heard of "Air cooleds Only" in Prescott Arizona ? Are they good? I'm going to have them do the rebuild--

thesamba.com is another forum that has ton's of feed back threads -- but it generally ran by stock Nazi's LOL

http://www.thesamba.com/vw/forum/viewto ... ir+cooleds