2.0 bus block w/ 914 heads & cylinders

[odie]

I was thinking (dangerous words)...

what about using a 2.0 bus hydralic short block (case, crank, hyd cam, lifters) with 914 1.8 heads, piston and cylinders? kinda a hybrid motor.

would the 1.8 cylinders match up to the 2.0 bus block or are they too small?

[jamcleod]

why not also go with 2.0L bus pistons and cylinders? the 80-83 air cooled vanagons are basically (i did say basically...) 2.0L L-jet type IV engines. bus p/c sets are about $285 so unless you are reusing a 1.8 set why not use 2.0 p/c's on a 2.0 block? someone will chime in to remind/point out differences in exhaust port shapes (79-83 bus heads are called "Vanagon heads" due to their square ports). i suggest researching the differences in crank throw. something tells me that 1.8 pistons don't match 2.0 crank. like, you can't put euro 2.0 pistons on a 1.8 block so vice versa shouldn't work. that is, the 1.8 has a different stroke than a 2.0, 2.0 is 71mm (???). one reason i think this is because two 96mm pistons sets are sold, one for a 2L and one for a 1.8L on EBS (engine builders supply). someone correct me if i'm wrong.

[odie]

I was thinking of using the vanagon block for the hyd camshaft (performance hyd cams are available) with my 914 1.8 heads (bigger valves than Vanagon). By staying with the 914 heads is no exhaust port issue and they should flow much better that the 2.0 vanagon.

For pistons, I would probably go with a big bore set instead of the stock vanagon or 914 ones. But I didn't know there are different piston sets for different cranks. I assumed the rod length would be matched to the crank (stock vanagon crank and rods should be fine). do the pistons have to be matched to the crank or rods?

Am I right in assuming that the 914 1.8 heads could be machined to fit whatever bore cylinders are used?

[Dave at Pelican Parts]

Using 1.8 P&Cs on a 2.0 crank/rods will either give you ~1/4 inch of deck height (i.e., way too much) or will cause the pistons to pop out of the cylinders a little at TDC. I can never remember which way that works.... Either way, it's not really something you want. The wrist pins are at a different height in the piston due to the different crank throws.

The 2.0 rods will only work on the 2.0 cranks, the rod journal diameter is different by 2.5mm.

The "register" where the cylinders seat in the 1.8 head is the same as that in the 2.0 head. No problems on that account.

--DD

[odie]

So the pistons & cylinders are specific to the cranckshaft stroke & rod length? Does that means that there are (if available) 2 different sets of P/Cs for any given bore size? one set for the 1.7/1.8 engines and a different set for the 2.0 engine because of the longer stroke?

Now what about "stroker" cranks & rods that match neither 1.8 or 2.0 specs? Does this then require additional P/C matched to those strokes specifically?

Does the 2.0 Vanagon have the same stroke and rod length as the 2.0 914 block? If so, would then P/C be interchangable between the two? Say for example...using 914 2.0 big bore pistons on a 2.0 Vanagon block?

[jamcleod]

pretty sure the vanagon and the 914 2.0L are "identical". one difference is oil filler and another is dipstick. i got into 914's because i had/have (son now has it in UT) an 81 vanagon. bought some typeIV 2.0L at a swap meet not knowing about the differences in exhaust ports planning on putting one in the vanagon for 50% more HP!! there are some minor differences between cases but i think crank, cam maybe and many parts are the same. i've made a database of parts and 85% of bus parts are same as 914 parts. so, with a 914 engine all i needed was a body to put it in, and the rest, as they say, is history........

[odie]

My first 914 dropped a valve when I was buying it so the seller put a 2.0 vanagon engine in. No more power than the 914 1.7 motor. Probably due to the single weber carb and bus heads. But I did like not having to mess with the valves.

I wonder how a vanagon motor will run with 914 heads, pistons and FI?

[Dave at Pelican Parts]

Originally posted by odie
So the pistons & cylinders are specific to the cranckshaft stroke & rod length? Does that means that there are (if available) 2 different sets of P/Cs for any given bore size? one set for the 1.7/1.8 engines and a different set for the 2.0 engine because of the longer stroke?

This is true for the 96es. I don't know if it is for any of the other aftermarket sizes.

Now what about "stroker" cranks & rods that match neither 1.8 or 2.0 specs? Does this then require additional P/C matched to those strokes specifically?

The stroker cranks do not require special pistons, necessarily. For a given stroke and piston pin location, you can choose a rod length that will let you build the motor without tons of shims or tons of flycutting. Conversely, if you have to use a particular set of rods then you may need to have special pistons made, or you may have to do lots of shimming or flycutting.


[quote]Does the 2.0 Vanagon have the same stroke and rod length as the 2.0 914 block? If so, would then P/C be interchangable between the two? Say for example...using 914 2.0 big bore pistons on a 2.0 Vanagon block? [QUOTE]

The crank and rods are the same. The cylinders are the same. The 2.0 Bus and Vanagon pistons are lower compression than even the US-spec 914 pistons. Using 96es that are intended for use with 2.0 crank and rods will work in either the 914 or the Bus. As was noted, most of the "hard parts" are either the same or swappable.

--DD