Is there a difference in a 2.0L out of a bus as opposed to a 2.0L out of a 914? I was under the assumption that a bus engine had different heads. I don't know where I heard that. Maybe I just made that up.

This is true.

There are a number of differences between the two. Just a few I know of (Depends on the year of the bus vs 914):

Bus:
4 bolt intake heads with smaller valves
No windage tray
Different cam
Used L-Jet for I think all versions
78-79 came in a carb'd version that had a mechanical fuel pump
Bus engines are lower reving torque monsters compared to 914 2.0s

There are tons more differences I'm sure. That's what's off the top of my little head.

Many of the few differences you 'know" are wrong. The carbed versions were 1972-1974, all the others had L-jet. The cam was the same until 1977, AFIK, when they changed to hydraulic lifters. They'll rev the same as 2.0 914 engines, but the power is somewhat reduced by the head design, the hydraulic cam, and the L-jet EFI.

The Cap'n

Doesn't the bus engine also have lower compression? I recall seeing deep dished bus pistons before ...

yes

Frig an egg, goes to show how much I DON'T know. I have to remember to keep my mouth shut, some poor idiot might actually listen one of these days.

Bus pistons....yes in a 914. :disgust:

So, has anyone put a bus engine in their 914? Is it good? Bad? Why would you want to?

The reason I ask is I have access to one. I would like to get 120+ HP and I wanted to know what kind of mods I would have to make to a bus 2.0L.
Probably not worth it.

There is a "bus" engine in my 914.

At least, it was a bus engine at one point. It was built into a 120Hp 2056, probably similar to what you have in mind. There are a few differences from 914 cases.

1) the dipstick is different for a bus. I carefully pulled the dipstick tube out and put in a 914 tube.

2) no taco plate oil temp sender. I scavenged one off another engine I had. The location is there, but the taco plate on the bus is just flat, it does not have the sender mounting location on it.

3) you can not use the oil temp sender off the 914. There is a big hunk of case in the way. You CAN use the short modern VDO sender, but then HAVE to use the 2 1/16 inch VDO oil temp gauge, not the big one from the 914. Other option is to hog out the case for the 914 sender to clear. I did not go that route.

4) Bus engine cases tended to warp around the registers. Mine has to be surfaced in order for the cylinders to sit in the case and be flush. This can happen to all T4 cases, but bus cases are especially prone as they were pushing big assed buses instead of little sports cars.

5) there is an oil gallery at the front of a bus case that needs to be plugged. I forget what its for in a bus. mine had a simple block off plate made from scrap aluminum.

I used the bus case as the journals were std. The 2.0 914 case I had was bored out and I was having a hard time finding bearings. Also, the oil galleries on my bus case had been tapped, and the 914 case still had freeze plugs.

Zach

If the oil galley is at the bottom of the case (cooling fan end of engine, opposite side from the oil cooler) then it's possibly for an oil fill. My Vanagon has an oil filler that is accessed by a door behind the license plate. That's where the dipstick is and the cap over the oil filler.

to what Zach says plus
Totally different flywheels
Low CR 7.3 to one
Tiny 37x33 valves in the heads
78 and later came with the crappy hydro lifters and cam
usually the cases are warped and need work
Heads are shot by 100k and drop valve seats, toss em

With lots of work a bus case can work as the crank, rods are the same but you have to put that little sleeve in the end of the crank

Bus crankshafts have the pilot bearing (same part as the one used in a 914) installed in the crank because the mainshaft is longer. Bus cranks for use with an auto trans don't have the bearing. 914s have the bearing in the flywheel. The bearing in the bus crank doesn't interfere with anything in the 914 application, so it can be left in place.

The Cap'n

Since I am currently running a 2.0 bus engine...They work once modified to fit a 914 (dipstick). The hydro lifters do work, but will limit the extreme high RPM. They have torque, but fade quick over 4500. For a temporary engine, go for it. For a 100+ hp engine, forget about it. The heads would never work.

In addition to the big dish in the piston ( lower compression) the connecting rods are more robust at the large end and weigh much more than a 914.

True, but when I have had the cranks worked on they pull the bearing so "IF" you are going to use a crank without the bearing put a bearing in or that stop. Otherwise the bearing on your 914 flywheel will move around into the crank and the pilot shaft will flop around.


Nah, the rods and crank are the same, even have a 039 part number as Porsche figured out how to built the 2.0L as VW thought you could only go to 1800 with a 66mm stroke.

Another difference, the bus cases for the carb'd engines have a bronze sleeve that goes 'through' one of the oil galley holes by the flywheel end, for the mechanical fuel pump pushrod. When you plug those holes in the case, you have to leave that one alone as going through it will screw up your oil pressure.

Besides blocking up the pulley end flange for the oil fill, you have to block the flange for the fuel pump also.

The finish on a bus case isn't as nice, also, like more casting marks, burrs, not as shiny.

Some bus cases don't have the slots to put in a windage tray, even, but some do.

The hardest part I would think would be making the hole for the tube to check the oil level, as bus cases don't have that steel tube coming out the top.

The 2.0 bus heads are worth scrap $ and nothing more. Only because they have been so heat soaked and used up pushing the big box around that the aluminum casting is fatiqued.
I quit working withused bus heads ~4 years ago.

New (or even slightly used) AMC 2.0 bus heads can be worked into great heads for a 2056 (or a 2316 for that matter).

The busses have a 15cc dish in the piston, but the 2.0 bus heads have ~49cc chambers compared to the ~58cc 2.0 914 heads which also have smaller dish pistons, ~7cc's in the U.S. IIRC

That's just not true. They're EXACTLY THE SAME.

The Cap'n

Do you guys just sit around making this shit up? The needle bearing is pressed into the flywheel. If it moves, there's something wrong with the flywheel.

The Cap'n

"Do you guys just sit around making this shit up?"

No.

The 914 2.0 is made of a hypereutectic, higher midi-chlorian alloy which gives it better stability, lightness, and strength

Huh? You mean rust? Naw, they both rust equally.

All the 2.0 bus engines I've seen were injected, mine didn't have the fp mount. Capn would know for sure.

I had one come loose and slide into the crank which didn't have the stop pressed in so the pilot shaft flopped around tossing tranny fluid out the seal.
Make it up? Why would I do that as enough weird shit has happened to me over the years....since 1969 on aircooleds.

Ah yeah, I was explaining the difference between ALL bus engines. The 2.0 busses were all fuel injected so they would have had electric fuel pumps and that flange not broached.

Something else not mentioned previous, but bus 2.0 cases lost the oil control valve (I think it's called that - the one below #1 cylinder) on account of the hydraulic lifters. I think 914 cases all had it as they all used mechanical lifters.

GC cases don't have it.

I have a 2.0 bus in my 914. Engine code says it produces a whoppin' 67 horsepower. Supposedly it has Porsche heads on it - says the PO. Also has carbs. Has nice torque in 1st/2nd, but beyond that - it's a wheezer.

That's why I'm putting in a /6

I never knew that. I wonder why?

Something else, I have never seen discussed in any forum, the differences in specifications listed in the 914 Technical Specifications book and the ones in the Bentley Transporter Manual. If they're right and we're putting the same main seals in, it's no wonder I can't keep my flywheel and clutch from getting oil on it in the 914 case. (my bus case leaks there, too actually). And then main bearings...5mm is a big difference....it seems like one of the books is wrong?

look to see if the heads have 3 intake studs then you'll know if it has Porsche heads

I think the red colored rear main seal is better than the black seal which leaks...Also check to see if your flywheels have a groove in em where the oil seals rubs which yes, causes leaks.

My Triple Beam disagrees. I _had_ a set of 914 2.0 rods that weighed about 770-780 grams, very thin on the small end. The ones I got back from the shop weighed about 810 grams, much thicker at the small end. (Not going to take any re-work back there! ) Later production perhaps? If you have the good ones, make sure to get the same ones back, is all I'm saying.

Anyways, the top end just seemed diminished, compared to what I remember of the tired 2.0...