Crank confusion

[Timas]

Hello all.
I tried doing a search with no results ( could be the verbage)
Are all cranks the same lengths regardless of what they came out of?
I've mentioned this before in my initial newbie intro.
When I swapped my short block, I was given a block from a early bay.
I need to gain way more torque at lower rpms. Lots of long hill climbs in my area.


What we're working with.
1977 type2B bus
Vw "x" case
90.5mm pistons?!
L jet F/I

Thanks to all in advance.

[AdminSteve]

If you are referring to stroke length then No they can be different depending on the engine type and displacement. Your year would have been a 2.0 liter with a 71mm stroke and 94mm bore Earlier was 69mm stroke and 90mm bore

AdminSteve

[Timas]

Thanks Steve.
What I had meant was actual length. What category of motor am I to search for?
Will a type 4 crank fit or does it need to be directly for a 2.0?
I have no machine shop around so I think I need to stick with the 90.5mm I have or maybe some 93mm whittled down to fit the 90.5 case?
I would like to upgrade to maybe 74 or 78.4 sized crank.
I don't think the clearancing would be that much nor hard to do.

[AdminSteve]

You are looking for a Type 4 engine
All Type 4 cranks have the same dimensions, so a 1.7l and 1.8l is the same as a 2.0l (only difference is the stroke length)
It might be easier to just find a 2.0l donor engine, the amount of work to build the stroker type 4 might be more than its worth.

AdminSteve

[Timas]

Appreciate the clarification.
I was hoping to try and build something in the 2.0 range while building low end torque.

[Bruce.m]

The rods on a 2.0 crank are also different.
If you remove a piston pin and example the small end of a rod you can tell which (big lump on the end of the 1.7/1.8 rod).

The 2.0l crank is 71mm stroke. The 1.7/1.8 is 66mm.

[Timas]

Much appreciated.
I apologize Bruce, I am not understanding how I am to tell the difference. I am to measure the I/D of the small end of the rod?
Rod length 1.7/1.8 vs 2.0?

[Bruce.m]

Nope. The ID is 24mm on both.
The 1.7/1.8 rods have a square lump on the end. Quite distinctive & odd looking.

Example here.

https://www.heritagepartscentre.com/uk ... built.html

[Timas]

Ahh.
That is a very unique feature.
Funny, every time I get an answer it leads to another question.
So, how am I able to run 2.0 rods with 90.5 pistons?
That has to have an effect on something right?

Or, is it irrelevant?
the only effect being the amount of compression due to diameter of piston head.

[Piledriver]

Most of the following is just for info, you have a 2L unless some shennanigans went on---but I have seen it.

A 2.0 T4 is 94mm bore 71mm stroke with a 131mm long rod, 50mm rod journal and rods you could effectively use to kill zombies.
It shares nothing with a T1 other than layout and the distributors can swap, but the advance curve differs.

The 90.5 pistons you speak of are probably for a t1, so 22mm pins. Strangely the deck height is almost the same as T1 "A" pin height.
(90.5/91mm oversizej P&L for 1700s once existed, but I digress)
2.0 rods are 131mm long c/c 1.7/1.8 are 127mm. All use 24mm pins from the factory.

If you are into calculating stuff a t4s stock deck height is 202mm for 1.7/1.8 and 202.5mm for the 2L versions.

If you are starting with a 1.8 or 2.0, I'd stick with it.
If you are starting with a 1.7, you have a few choices to make, only the heads differ, and they can be opened up to 105mm as the 1.8/2.0 are.
(cylinder register size) Opening up 1.7 heads for the 3 or 4mm larger bore is not the huge win you might think it is...

Any of them built properly can put out decent power, even a 1.7, latter may end up more reliable, has better cooling (more meat in the heads and block) and the heads flow better than the 2L bus heads, almost as good as the 1.8s heads, but with smaller valves. Port velocity is a very good thing.

[Timas]

As usual ,the responses for my questions are very informative. I am going to begin having motor build questions soon. Piledriver, do I need to ask engine build questions in another sub forum?

Last question….for now.
Of the information given to this point, I believe that I can build at least a 1905 and perhaps up to a 2110?

For a vehicle weighing roughly 3,200lbs and needing to be able to have enough torque at low RPMs to get up and down hills without having white knuckles from rage; what size crank would I start with? 74 or perhaps 78.

[Piledriver]

The longer the stroke the more interesting the build gets.
The bigger the bore the more likely you will have head sealing issues.

78mm is getting involved as far as clearancing for the cam and case, as well as fabricating cooling tin add-ons due to it being wider...although there are choices for h-beams these days with the 2l rod journal...

The further you diverge from stock, the costs go up in an almost exponential fashion, particularly if you are getting heads built (count on it)..., an you are also looking at a stand-alone EMS as LJet simply won't cut it on a much larger engine. (LJet has very limited tuning ability, but the intake itself s a quite good design for the application on a ~stockish or a bit bigger engine)

A set of Webers look and sound awesome but will not make power where you want it in a Bus.

You can get a bit more out of a stockish engine and keep stock reliability and better drivability with a decent stand alone EMS, most of the real drivability magic is in the ignition map, the fuel side you simply have to give it what it wants.

Also note you are not going to make any significant gains with the factory heat exchangers hanging on the engine, an under floor diesel heater will probably be a Very Good Idea along with an A1 exhaust.

[Timas]

I am not sure if I can alter my fuel system. I need to pass smog in California and I think tunes are a no no.
Unless my smog guy doesn’t give a s@&t; fairly sure he won’t.

So going with a 74mm crank would provide minimal gains?
Or stock 71mm crank and maybe a cam upgrade.

The long hill climbs really need to be addressed.
People are complete A holes and it makes driving more dangerous.

[Piledriver]

If you keep the stock exhaust you are pretty stuck with stock everything, power level wise... mild cam with a bit of extra ex timing to compensate for the horrible exhaust is probably the best you can to, but ljet has no computer connection, if the intake looked stock you could easily run cleaner than the ljet with a stand alone ems. Most modern ecus these days will easily fit in an ljet ecu can....

Doesnt stuff go exempt after 25 years anymore?

[Ol'fogasaurus]

https://www.bing.com/search?q=what+ae+h ... dd&pc=LCTS

For what it is worth: this talks about high lift, short duration cam shafts and what you can get out of them.

I run them when on the sand for climbing the dunes but not over revving the engine. At one time the reground high lift short duration "re-grinds" (cam shafts) were used a lot on "junkers' running on short duration oval clay race tracks.

Again, this is info just for what you might learn about them.

Lee

More discussion on the subject: https://www.bing.com/search?q=high+lift ... 02&pc=LCTS