So What's the First to Go?

I've been reading the two main aircooled forums and from what I can glean the big problem with 'big' motors is low quality parts. I don't see any reason why a big motor shouldn't last a long, as in 50,000 miles, time. Seems there are a lot of junky parts out there that are causing the premature demise of air cooled motors.
Ron

I was yacking it up with a mechanical type at the lunch counter today and he was pretty convinced that Type1 VW engines built at 2110 to 2275 cc's "don't last"

I know we've been down this road in the my kind versus his kind of engine before, but aside from driver stupidity or engine builder error, etc, "What is the big wear 'em out factor" people seem so sure of?

I see contributors to this forum with larger engines, are you rebuilding them every winter?

Why the bad rap?

Medicine Man

(Message Edited 1/17/2003 10:12:56 AM)

Quality parts definitely make a difference along with keeping up with maintenance. The main thing to keep an eye on with larger engines, from what my builder tells me, are the cylinders and pistons. Their expected lifespan, as least for 94s (I have a 2176), is about 50k miles.

Type 1's have been around so long that it is surprising that the "junky" parts suppliers aren't weeded out. I guess there are enough "have I got a deal for you" types to snag the bargain bound "fish on the line" types.
Just MHO.
John H.
processed by jph spell checker. ha.

(Message Edited 1/17/2003 11:27:31 AM)

Lots of builders strongly suggest two additional gauges to the compliment: oil temp and cylinder head temp gauge. As can be imagined both are vital to the health of a air cooled engine.

COLTON: I thought your builder's idea of ducting cool air to the carb area was terrific. I will likely copy it. I know I asked you earlier, but where does the duct originate; I am a little fuzzy about that.

Extra guages are a great idea and I found some nice VDO ones with mounting cups that are tucked up under the dash. According to an infrared temperature gun, they are very accurate as well. Tip on that... install the sender where the oil exits the engine so you get the hottest reading, not the coolest.

Erik, as far as the system in the engine bay I have for cooling, it is "three-fold" and, in my opinion, listed in order of importance:

First, the bottom of the engine compartment is sealed with some engine tin and the gaps are taken care of with rubber hose... used like a gasket... like that stuff you seal your front door with to stop drafts. This is to try and prevent heat from rising off of the exhaust into the engine compartment which is apparently pretty bad with our Speedsters.

Second, the ducts... holes were drilled between the engine compartment (right by the carbs) and the wheel wells and then sections of hose with filter ends/tips (filters in the wheel wells) were inserted and then sealed. The filters keep road grime out, but with sticking out kind of help direct cool air into the compartment. They are only visible if you really stick your head up in there.

Third, a couple of nuts where used on the deck lid hinges to lift it up a little (barely noticeable) and allow air in that way as well. Some people might not like that, but since I am an "outlaw guy" with a flared VS and more performance oriented, I'd rather do what I can to keep everything cool.

I did have pictures of all the modifications, but they were lost when the files disappeared. I will try to re-post them this weekend. Hope that helps.

Paul:
Engines of the 2110, 2165, 2275 size have a 94mm bore. The large bore tends to make cylinder sealing difficult. Also, thermal distortion increases when cylinder bore does.

Longer stroke engines that use too short rods also have increased side loading in the cylinders. The use of a short rod ratio increases low end torque, but decreases cylinder wall longevity. If you buy a stroker crank, you also need to make sure that you get the right length rods to maintain some sort of decent ratio. An experienced engine builder should know the score here. If not, you have a guy with miles of experience at a depth of .0001mm.

As has been mentioned, quality parts last longer. Cheaper parts are less expensive to replace once; on the other hand you get to replace them more often. "You can pay me now or pay me later."

One other item I would mention that I am sure will start a firestorm. Thermal expansion is more of a problem in an air-cooled engine than in a liquid cooled engine. I find it useful to always warm up my 2007cc (90.5 by 78) air-cooled for at least a minute before I try to drive it.

COLTON: I agree wholeheartedly with your three ideas: a sealed engine compartment is a must, your retro carb ducting sounds cool and during the hottest weather providing extra air for the engine compartment.

I had JPS retro-fit Carrera louvers to my engine lid so I believe that will do the same thing as raising the lid slightly. If during hot, summer highway driving the oil/head temp gauges say I am running hot-ish I understand some bug guys cut a hole behind their license tag to allow more air into the compartment.

Back to your carb ducting -- I checked the photos of your car on your profile page and didn't see the ductwork, but then it dawned on me the hole is via the wheelwheel and not cut through the firewall, duh, right? What diameter hole and what type of filter were you talking about for the feed-side?

Erik, I posted photos in a folder under my main folder (Coltons 58 Speedster) called "cooling". I hope you find them useful. You are right about the wheel well... I took a photo of one of the wheel wells and you can see it. The hole is 2 inches in diameter and the filter is the hose and filter from a JAZ breather. Your louver does basically the same thing as raising my deck lid.

Alan, wouldn't you say that while there are some minor sealing issues with the 94s, a breather box handles that? And, as far as thermal distortion, aren't the cylinder walls of 94s actually the same thickness as the 90.5s while 92s are thinned out and thus more susceptible to distortion?

A breather box, at least the ones I am familiar with, vents the valve cover, not the head sealing surface.

The cylinder walls are nominally the same for 90.5mm or 94mm bores. However, the 94mm bores have about 4% more circumfrence. It would appear, from actual experience, that the 4% does cause a significant amount more distortion. I drive a 2007cc equipped Baja Bug. My (bought used) engine is a Pauter Machine built unit with almost no stock parts in it. Clearly Pauter could have just as easily used a 94mm bore to get extra displacement. They did not. The reason is that the smaller bore was considered to give longer engine life.

The 92mm bores should, IMHO, be avoided. The 92mm bore cylinder walls are much thinner than either the 90.5mm or 94mm cylinder walls. The thinner walls are noted for flexing and short engine life. The 92mm bore is associated with 1835cc displacement. Please note: I have never owned/used an 1835cc, I am just telling you what several engine builders, both pro and anmateur have told me.

Well, my 2,110 was 82mm stroke by 90.5mm bore on a new full-flowed VW engine case. Counterweighted crankshaft, 12.5 lb. flywheel, and rods are forged chrome-moly. Late doghouse shround modified for type 4 oil cooler, 30mm oil pump, and 1 1/2 quart bolt-on sump. All rotating/reciprocating parts balanced. It will probably go 60,000 to 70,000 miles before it needs a ring and valve job unless the new owner flogs it mercilessly. Many 2 liter engines make it to 100,000 miles.

Cylinder bore issues aside, it is all the more reason to monitor the temperature of your heads and engine oil, especially if you live in a hot climate, do performance driving or take long highway trips during the summer. On the other hand if you mainly do around town driving and seldom cruise at 70 m.p.h. for hours at a time don't sweat it, enjoy your car.

George, I think your car is in for major abuse! ;-) Just kidding, I think Karl will take great care of it. Alan, I am sure you are right about the 4% making a difference. For me, it is something I am willing to accept. And yes, avoid the 92s at all costs!

On the subject of what goes first or longevity of a healthy Type 1 motor, here

For most engines a blueprinted oil pump with 26mm gears is fine (Gene Berg said that, too). Some Carreras had holes behind the license plate for additional cooling air input.

An oil pressure gauge is a good idea but cylinder head temp gauges are usually not necessary on most engines.

An air/fuel meter is not necessary except for initial carb jetting and tuning; after that it is superfluous. There are a lot of cheap-o A/F meters on the market; if yours is not a more expensive broad-band unit (just the 4-wire O2 sensor is $150) then it won't give very accurate readings.

Greg used a term in his response that I was going to ask about and now I think I see it more clearly...."WELDED" as it relates to the engine case.

This is where a little more beef is added on the notoriously thin third cylinder wall, n'est pas?

For the longest time I thought the unimaginable when I would read ad copy using the term welded case... I figured whatever components were in there, were never getting out :-(

So a 2275cc long block, welded, with good-quality sounding internals, flow through plumbing for a larger oil sump, etc, etc, etc is likely a good value at $1800. for those of us not inclined to build our own?
MM

(Message Edited 1/20/2003 12:28:22 PM)

Welded cases for high performance engines were only "necessary" on the 40 bhp and older cases, and many performance engine engine builders did not weld those because it usually warped the case. The new stock cases now available should not require any strengthening at the flywheel side.

Buying a used performance engine is like buying anything else - caveat emptor.

(Message Edited 1/20/2003 12:51:57 PM)

George,

Am surprised you are cavalier about head and oil temp gauges.

I have heard many professional builders express the opinion that if you run your car hard both are a good idea for air-cooled engines, besides that, they are inexpensive. You can have normal oil pressure range but your heads may be cooking. Of course as was stated earlier if someone is going to putt-putt around town and seldom/never take long summer highway runs then standard gauge combo is fine.

Erik, what's cavalier? If my engine is jetted and tuned properly and I test it under heavy load on a 95 F day and check head temperatures with a laser thermometer and know they're safe, why should I install a cylinder head temp gauge? My new engine will be running oil pressure and oil temperature gauges and be double checked for head operating temperatures so I don't feel a cylinder head temp gauge is worth the trouble, and some of the automotive aftermarket gauges are not that accurate.

If you want to use one, I would suggest an aircraft quality gauge ($) with a sender on each head and a selector switch.

George,
I agree with your comment on warped cases from welding.
I think that newer cases have more material behind #3. I don't know if the aftermarket Aluminum cases are thicker in that area. I would hope they took care of that problem.
When I first started building big engines, I saw my share of cracked cases behind #3 (even stockers crack there). At the time I did the machine work on this engine I was working at a Auto parts & off road shop with complete fabrication and testing facilites. We beefed up VW cases by welding plates behind #3 before any machine work was done on our big cylinder motors.


We welded VW cases all the time. The trick to avoid warpage was to bring a prepared case up to temp before welding; then control the temp as it cooled. Then let the case stabilize for a week or so, then do the rest of the machine work and align bore.

Greg B.

I agree with your comments George, but not everyone has your mechanical experience or maintain their car as well or even have the quality tools at their disposal as you.

I wonder how many Vw's dropped valve seats or cracked heads due to the owner being clueless, that was my point. I have VDO gauges picked out, maybe not the best but fit my budget. Frankly I would rather have a big idiot light and swap the oil pressure reading for oil temp function.

I wasn't saying you were wrong but what is right for you may not be enough for everyone else.

No big deal Erik; one of the problems with cyl head temp gauges is the senders. Most fit under a spark plug - they are hard to install without damage (initially and during spark plug changes) which can give a bad or no reading. Some tubo engine performance guys install senders under an upper cyl head nut/washer during engine assembly which eliminates the spark plug hassle.

Oh-OH, just when I thought it was Ok to get my wallet out...
So, even if a block has been welded, it may not have been welded well or properly?!?!?
SHIT.

Caviar Empty
MM

How ya doin' MM I will go with PORSCHE eny day. I love VW's but the diffrence is in the 10,000-100,000th. Can't make a race car out of a peoples car. Talk to me about them BUCS, and send me some pics of your SPEEDY. Doug MM

I here ya Doug, Porsche is still top on the mountain (although coming down a little with their new SUV---even Porsche sold out to the normal smow driver) . I just wonder just how much a 356 engine differs to a VW dual port. I also got in a little race with a guy that had a 356 coupe with all the stickers and go fast looking stuff (kinda like those rice burners with the wings and mufflers) and what do ya know----smoked him! The guy was very sad looking as I blew past him in my fiberglass dream machine. Oh well, sucks to have a real one and can't beat a replica!

J-P

Actually, a VW type 1 engine built carefully with premium aftermarket parts is probably stronger and more reliable than a Porsche 356SC or 912 engine.

they all have their applications.

I see tons of 356 and 912 engines at the SCCA events, but never any TI powered cars...odd.

And I see a whopping number of TIV powered production classed cars run a complete season on a 17-1800cc engine that makes 150+Bhp, and lives at 7K for 45 minute sessions as much as 8 times per weekend..

They are all tougher in different respects!! a 356 is the most expensive stock engine that can be built. I won't look at a stocker for less than 8K bucks, parts are insane.

Jake, Porsches at SCCA events without T1 engines is not odd at all; technically that would change the class they ran in, and 356 Porsches are vintage racers anyway.

Figures I would be asking questions and would find answers to them under a topic by Paul MM. Tryin' to find info on the 2000 cc porsche engine, and I found it. Thanks Paul DougMM

By the way paul why you using my handle, I'm med, your MORT

Jean-paul I stoped by Reeve's Porsche in Tampa, and after a typical goround with a young German mec who never even saw a 356 I got to talk to a young mec with some respect for an 'old timer' he said more or less the same thing about the after market VW parts.

Not to go to far back but........the 94 pc thing has got me thinking.
If you can get 50K out of an engine then have to pull the heads to refresh them why wouldn't you also change out the cylinders and pistons? A set of new pc's are 200 dollars so who cares, throw new ones in for good measure! Just seems like a lost oportunity for power. I do understand the heat thing though, I live in Southern CA and it gets hot out here.

J-P

j-p I work with engines that get a million miles. And I agree with you that when you have one down that's the time to fix what ever. I'm not sure how to get this across, but I'm looking for an engine that won't break. Some engines are desined and built to go only a 1/4 mile, but thay don't break in that time.

Doug, a Berg or Scat forged chrome-moly crankshaft, 4130 forged chome-moly rods, LN Engineering biral cyclinders (mine have cryo'd liners) with forged pistons, Schubeck composite lifters on a Web Cam camshaft, "blueprinted" Schadek 30mm oil pump, full-flow case with spin-on oil filter, Berg 3.5 quart bolt-on sump, correct engine build (tolerances, parts quality, rods not bent/twisted, etc.), adequate cooling, and proper maintenance should make for a 60,000 to 70,000 mile engine if you keep your foot out of it.

(Message Edited 3/28/2003 2:32:59 PM)

Thanks george, your cool doug And were is Mort Man???