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Thu Jul 19, 2012 9:39 am

Heyooo!! So I inherited a frankenstein engine with the 78 bay window I bought a few months ago... I looked up the engine code to discover it's a 1974 412 that's 1800cc... but it has 94mm pistons in it. One of the cylinders has some pretty bad scoring on the inside and could be honed, but then I'm looking at some blowback and a really sweet smoke cloud coming out the back as I'm rolling down the road from all the oil I'll be burning. I've been told that I should have 92mm pistons in there not 94s, but I have 94s... So it's been modified. One vendor suggested that I go bigger with 96s because any 94s won't fit the stroke correctly.

Anybody have any idea what is goin on here? Suggestions for a rookie?

Thanks!

--Jason

Thu Jul 19, 2012 11:11 am

Standard bore for 1800 is 93mm. Oversizes were 93.5 and 94mm.

2L is 94mm standard.

Thu Jul 19, 2012 1:09 pm

Yeah. I guess i kinda' figured they went oversize. Now I'm trying to figure out if they changed the stroke or anything else I didn't know about so I make sure to get the correct parts to fit it. Thanks for replying!

Thu Jul 19, 2012 1:26 pm

How to Rebuild Your Volkswagen Air-Cooled Engine by Tom Wilson is essential reading! :wink:

Fri Jul 20, 2012 5:27 am

10-4! Ordered the book, should get it today. Thanks for the tip!

Fri Jul 20, 2012 12:28 pm

The 2.0 liter Type 2/4 air cooled engine is the most powerful air cooled VW engine. I'm going back to buy one I found sitting with an automatic transmission on it for an investment! :twisted:

Fri Jul 20, 2012 4:02 pm

Mike Fisher wrote: The 2.0 liter Type 2/4 air cooled engine is the most powerful air cooled VW engine. I'm going back to buy one I found sitting with an automatic transmission on it for an investment! :twisted:

Actually...its only the most powerful in the 2.0L 914 format...not the bus format. The 1.7L with D-jet has more hp than the 2.0 bus I believe. Ray

Sat Jul 21, 2012 12:25 pm

corninyourpoo wrote: 10-4! Ordered the book, should get it today. Thanks for the tip!

Hey!!! Akron? Cool, my old stamping grounds! I guess Sgt. Hack's on Exchange and the Little Bug Shop on S. Arlington are both long gone, bummer. There's Elmar way out in Streetsboro, and if Semco on Copley Circle is still around, they used to carry Beck- Arnley ACVW stuff.

Is your car a local Akron car?

Sat Jul 21, 2012 12:26 pm

raygreenwood wrote: Mike Fisher wrote: The 2.0 liter Type 2/4 air cooled engine is the most powerful air cooled VW engine. I'm going back to buy one I found sitting with an automatic transmission on it for an investment! :twisted:

Actually...its only the most powerful in the 2.0L 914 format...not the bus format. The 1.7L with D-jet has more hp than the 2.0 bus I believe. Ray

Hey Gruenwald, wasn't the Bus engine just basically de- tuned for emissions with cylinder spacers, though?

Sun Jul 22, 2012 1:51 am

Mr. Tram wrote: "Hey Gruenwald, wasn't the Bus engine just basically de- tuned for emissions with cylinder spacers, though?"

Compared to 2L 914, bus 2L differs by having low compression pistons, different camshaft, different cylinder heads, and different fuel/ inlet system and exhaust.

Bus 2L had 70 hp, (un-smogged "rest of the world" models). In comparison, 412/914 had 80 hp in 1700 version.

Sun Jul 22, 2012 5:19 am

Tram wrote: raygreenwood wrote: Mike Fisher wrote: The 2.0 liter Type 2/4 air cooled engine is the most powerful air cooled VW engine. I'm going back to buy one I found sitting with an automatic transmission on it for an investment! :twisted:

Actually...its only the most powerful in the 2.0L 914 format...not the bus format. The 1.7L with D-jet has more hp than the 2.0 bus I believe. Ray

Hey Gruenwald, wasn't the Bus engine just basically de- tuned for emissions with cylinder spacers, though?

Yep...compression was the major part of it...but it was done with a combination of shim and dished pistons....along with a few small details like a different advance curve. It "might" have had a different cam as well.

I have never been too clear on bus cams but I do know there was a different part # cam for bus.
If an engine was 1.7L 411/412/914 or 1.8L 412/914 or US version of 2.0L 914....they all had the same cam. Ray

Mon Jul 23, 2012 1:15 am

Bus manual 1700 had different cam than 1700 automatic.

Basic 411/412 1700 (not available in USA) had twin 34PDSIT carbs, it's own cam, (timing different from D-jet cam), and 7.8:1 compression and made 68 hp.

Bus 1700 manual retained this cam but compression dropped to 7.3:1, and power from 68 to 66 hp at 4800 rpm's. (High revving, 5.375 diff).

For automatic 1700 bus a short duration low lift cam was introduced. This killed top end to 62 hp at 4200 rpm's. One reason presumably to reduce possibility of hunting between gears of 3 speed automatic.

All 1800 and solid lifter 2L bus engines (manual and auto), got this "automatic" cam, and max power also now at 4200 rpm's . Maybe to limit power for reliability reasons, as this was also a commercial application. (Company drivers).

Vanagon hydraulic cam had even shorter duration. Main difference is earlier closing exhaust valve/ less overlap. Not sure if 79 hydraulic bay had similar timing. Result was slight loss in torque compared to 2L solid lifter engine.

This info referring to "rest of the word" bus engines, where nearly all retained 34 PDSIT carbs /26mm venturies and 72-74 style heat exchangers (later ones with square exh ports), until the last aircooled vanagon made around 82.

I do have timing details relating to the various bus cams. But i am getting off topic, do not want to pollute original poster's thread.

Mon Jul 23, 2012 6:48 am

I have to say that how to rebuild book was immensely informative... Turns out I do in fact have a 1974 type 4 1800cc that's been converted to a 2.0. The previous owner changed the rods, etc... All the vendors were saying I should go with 96mm for the pistons because the 94s wouldn't fit an 1800... Unless I have 71mm rods. The good thing is, I know what I have now.

Mon Jul 23, 2012 4:07 pm

dawie wrote: Bus manual 1700 had different cam than 1700 automatic.

Basic 411/412 1700 (not available in USA) had twin 34PDSIT carbs, it's own cam, (timing different from D-jet cam), and 7.8:1 compression and made 68 hp.

Bus 1700 manual retained this cam but compression dropped to 7.3:1, and power from 68 to 66 hp at 4800 rpm's. (High revving, 5.375 diff).

For automatic 1700 bus a short duration low lift cam was introduced. This killed top end to 62 hp at 4200 rpm's. One reason presumably to reduce possibility of hunting between gears of 3 speed automatic.

All 1800 and solid lifter 2L bus engines (manual and auto), got this "automatic" cam, and max power also now at 4200 rpm's . Maybe to limit power for reliability reasons, as this was also a commercial application. (Company drivers).

Vanagon hydraulic cam had even shorter duration. Main difference is earlier closing exhaust valve/ less overlap. Not sure if 79 hydraulic bay had similar timing. Result was slight loss in torque compared to 2L solid lifter engine.

This info referring to "rest of the word" bus engines, where nearly all retained 34 PDSIT carbs /26mm venturies and 72-74 style heat exchangers (later ones with square exh ports), until the last aircooled vanagon made around 82.

I do have timing details relating to the various bus cams. But i am getting off topic, do not want to pollute original poster's thread.

Thats the best overall info I have seen on bus cams. To add to that....the early 411's carb only cam (noted as Z grind) is the same basic cam timing that Web cam uses for their #73 for fuel injection. It allows the addition of a little more lift and durationwhile keeping the overall usable intake valve timing needed by D-jet. Ray

Mon Jul 23, 2012 6:18 pm

Consider it polluted. Oh well. For those who made helpful suggestions--thanks. To all the thread terrorists--you are speaking another language... Buuuut good luck with your thingamajiggers anyway.

Tue Jul 24, 2012 1:26 pm

Tram wrote: corninyourpoo wrote: 10-4! Ordered the book, should get it today. Thanks for the tip!

Hey!!! Akron? Cool, my old stamping grounds! I guess Sgt. Hack's on Exchange and the Little Bug Shop on S. Arlington are both long gone, bummer. There's Elmar way out in Streetsboro, and if Semco on Copley Circle is still around, they used to carry Beck- Arnley ACVW stuff.

Is your car a local Akron car?

aww man... somehow I missed this! I've been to Elmar a few times to trade out parts... There's some guy down in Suffield on 224 that I need to chat with one of these days.

Not a local bus... Not sure where it originated... The engine and bus were in columbus with parts in boxes... The interior was in toledo. That was a lot of fun getting that all together... It's been a saga, but man it's fun!

Tue Jul 24, 2012 6:21 pm

corninyourpoo wrote: Tram wrote: corninyourpoo wrote: 10-4! Ordered the book, should get it today. Thanks for the tip!

Hey!!! Akron? Cool, my old stamping grounds! I guess Sgt. Hack's on Exchange and the Little Bug Shop on S. Arlington are both long gone, bummer. There's Elmar way out in Streetsboro, and if Semco on Copley Circle is still around, they used to carry Beck- Arnley ACVW stuff.

Is your car a local Akron car?

aww man... somehow I missed this! I've been to Elmar a few times to trade out parts... There's some guy down in Suffield on 224 that I need to chat with one of these days.

Not a local bus... Not sure where it originated... The engine and bus were in columbus with parts in boxes... The interior was in toledo. That was a lot of fun getting that all together... It's been a saga, but man it's fun!

Ahhh, I thought this was a Type 4. Never were a lot of those around Akron, and I knew most of 'em.

The guy in Suffield is ringing a very vague bell. Maybe he's been around a long time? I think there was a shop in Kent too, but can't remember any more.

I apprenticed at what's now Dave Walter, but it was Henry Motors, Inc. then. My first "lot lizard" job was at R.B. Harmon in Canton. *Almost* went to work for both Burley VW (later Datsun), and Dale Haggarty in Caucasian Falls. :lol: I think Haggarty's long gone, too!

Wed Jul 25, 2012 5:20 am

Ha! Well, the engine is a type 4 that came from a 412--at least that's what the engine code says... Came with the bus we bought--not in it.. just beside it... Givin' it new life and new skin! Those 412s are pretty rad though... I grew up in San Diego and my buddy's pops had one. Of course as a kid, I didn't know how sweet it was.