TheSamba.com :: View topic

Wed Apr 23, 2008 1:28 pm

hello, i have a 1973 bus and i think i have a 411 or 412 engine installed. because the oil dip stick is on the top of the motor. is this a good motor.here is the number on the case. cb073163

Wed Apr 23, 2008 3:19 pm

I believe for 73 the US engines for Type 2's and Type 4's were almost identical inside. You shouldn't have any problems running an engine out of a 411 or 412 in your van. Whether it is a good motor will depend on it condition.

Wed Apr 23, 2008 6:02 pm

thanks for the help.

Mon Apr 28, 2008 6:31 am

Type 4 car engines have a higher compression ratio than the type 4 bus engine. The car engines have domed pistons and the bus engines have dished piston engines. The theory is that the lower compression will last longer in the heavier, less areodynamic busses. I have rebuilt both engines, and can speak from experience. Hope this helps, and good luck with your project.

Mon Apr 28, 2008 7:06 am

The 411/412 motor will tend to run a little hotter in a Bus (Due to the higher compression as discussed above) but other than that, it should do ok.

Mon Apr 28, 2008 8:50 am

Later 411/412 engines used the same pistons as a bus. Don't know when the change was made, but I think it was for the 72 model year.

Tue Apr 29, 2008 9:44 am

I'm a little confused by the information presented here, I don't know about the Buses, but from discussions on another forum, the Type 4 car 1700 engines were high compression throughout production '69-'74 (available in '74 only in the 2 door 412 sedan). IIRC, there were also some special California 1700 Type 4 car engines with slightly less compression for at least '73, no? ('74 412 2 door sedan not available in CA). I'm not sure how the 1800 Type 4 car engine's pistons ('74 4 door type 4 sedan and wagon only) compare to the 1800 Bus motor pistons, as the car engine's compression was lowered from what it was previously in the 1700. If they had the same pistons at any time, '74 seems like it would have been the overlap year.

Tue Apr 29, 2008 9:59 am

yes,,huber ,,i have see that me too in the type 2 forum,,the piston for the type 2 ,,, 1,7 is différent ,,,but,thy are the same for the 914,,1,7,, bb412

Tue Apr 29, 2008 12:44 pm

According to my Haynes manual there were (at least) three different pistons use in 1700 411/412's. There was an 8.2 CR piston, a 7.8 CR piston, and a 7.3 CR dished piston which was used in Calf.. My 411/412 parts book shows that piston changes occurred in Aug 71 and Aug 72 and that there were piston differences between engines FI and carbs in the same year. The parts book lists a total of 8 different pistons in use including the dished Calf piston and earlier pistons with 23mm pins.

Haynes is of course a British publication so there may be differences here in the states, while my parts book is an August 1972 so won't show later changes.

It is easy to see why this is confusing.

Tue Apr 29, 2008 5:28 pm

412 engines run hotter in Buses.