A20 vs BXX crank pulley inner diameter.

[bobafett]

Does anybody know the diameter of the crank pulley where it slides onto the end of the crank?

I am needing to fit a crank trigger wheel onto my car and hoping that something like this: http://www.directignition.com/trigge...220-72410.html will fit.

If anybody has that information it would be really helpful. I can probably take off my crank pulley to measure, but it won't do any good if I don't know the diameter of the B16/B18/B20 crank pulley.

Thanks guys... if I manage to find anything out I will post it here...

[carotman]

I'll measure the A20A1 pulley I have here later today. I'll come back with the answer

[bobafett]

Thanks,

Something to note, that may be relevant -

When building my motor I made the unfortunate discovery that not all crank pulley bolts (and possibly - crank pullies) are the same.

Here is the story, my machine shop LOST my crank pulley, bolt, washer, crank timing gear etc. After looking for weeks and them not finding it I just said screw it and bought a new setup from the dealership.

The bolt from honda was too small to thread into the end of my crank, so I could not use the bolt. However I cannot recall if the crank pullies themselves were identical, but I want to say that they were different somehow...

The motor I have built is supposedly a low miles jdm a20, but I don't know that for sure. I bought it off another member, and cannot verify its origin.

If I end up pulling my crank pulley to measure the diameter I will also verify the size and pitch of the bolt threading into my crank.

I will try to contact electromotive/unorthadox and see if they can give me any useful information about their pulley.

[bobafett]

Not an exciting update, but I have two contacts to try to get ahold of now.

Uwe (sp) @ Electromotive - 703.331.0100 x208
The guy I got ahold of claims that they have redone their B-series crank trigger kit, and he is unsure of what was changed, and whether or not the new version is ready etc. I am supposed to get ahold of uba/uva and he should be able to get me more info.

The guy that I spoke to also suggested that getting a universal trigger wheel and having it modded to fit my pulley would be an easy solution. But honestly I would love a small light one belt wheel, and I am not sure where to find something like that. I'm pretty sure ours are basic undamped metal, so I see no reason why a sweet aluminum unit couldnt be fabbed up.

Joe @ Unorthadox Racing - 631.586.9525 x12
Joe is the technical guy and will be back on Wednesday, but the guy I spoke to said he is not sure if Joe will be willing to give out measurements, but I will hope for the best.

Thats all I know for now.
Chris

[2oodoor]

Im loving this project, I needed to do some homework myself but have not had time.

Electo has been making their CK trigger ign a long time, I am surprized they dont have a BS, ETxx,ES2 kit that would fit an A20 already. The BXX crank end diameter is not the same I am pretty sure, but I dont know why you couldnt just adapt the wheel and hardware to a stock crank pulley, or is the billet pulley they use cut down to make the wheel fit inside so the magnet can be mounted inside the T cover... if that is the case then why cant you mill the stock pulley to accomdate that, if it is made of a material that wouldnt shatter if any bulk is cut away...

[bobafett]

I need to get ahold of my machine shop and see what they can do for me. I just want a single belt pulley and it will need to be modded up a bit to get trigger wheel on there.

I do not know how to handle the magnet mounting etc... whether the wheel can be on the inside, or if it will have to be on the outside etc...

I will do some more digging later on. I wonder how difficult it would be to get a custom pulley made by a company like unorthodox, hmmmmm....

[2oodoor]

It looks like it mounts outside the cover, but that picture on the link is not an A20. the idea is to have the reader magnet line up with the trigger wheel no matter where the wheel is. That established, the wheel could be made to fit the stock pulley in theory. Removing the AC and hardware clears out a space to fab up a mounting config.. for the magnet. It has to be a stable mount because the air gap has to be maintained.

[bobafett]

Right, thats another reason that lobbing off the other two belt tracks would be a good idea. gaining another inch or so of room to mount the pickup would be great.

But you are correct, the link shows a B-series DOHC single belt pulley from unorthodox racing, modified to fit a electromotive crank trigger wheel. electromotive just mods the unorthodox wheel.

[bobafett]

Ok, my machine shop says it shouldn't run any more than $100 to get the pulley chopped down to a 1 belt pulley, and the trigger wheel mounted on there and balance it all up when they are done.

But I have a lot of work to do before hand finding out what size outer diameter wheel will be used, and where/how to mount the pickup sensor. And the orientation of the pickup tooth compared to the pulley as well.

Any suggestions for pickup mounting?

Once I have a crank trigger setup I have opened up a lot of options for standalone ems and ignition systems.

SDS EFI, electromotive tec3 or tecGT (new), etc etc...

[carotman]

I measured the pulley hole and it's 25mm

[bobafett]

awesome. hopefully wednesday I can get ahold of joe at unorthodox racing and have him give me the size of the pulley on a B-series.

[2ndGenGuy]

Any suggestions for pickup mounting?

Could you weld a long, slotted tab onto the block? That way you can loosen and tighten the sensor to give it adjustment so that you can set it where it picks up the best...

[bobafett]

Ok, the B-Series inner diameter is 28mm. Also I'm pretty sure the offset is WAY off.

We can do a group buy on pullies, but would have to choose between single belt or stock belt configuration. We would need a minimum of 30 units, and cost would be around $180-$190.

A one off custom pulley will be $500-$600. If anybody has an extra pulley they will be willing to send to Unorthodox they can take measurements and see if anything they have is compatible or could be easily modified to fit. I don't have an extra pulley or I would already have one on the way.

So who would be up for an $190 single belt group buy? I doubt we have enough people that have AC and PS removed, but it sure would be nice. On the other hand I think there is a chance we could get 30 triple belt orders, but it would probably take a while.

[MessyHonda]

Ok, the B-Series inner diameter is 28mm. Also I'm pretty sure the offset is WAY off.

We can do a group buy on pullies, but would have to choose between single belt or stock belt configuration. We would need a minimum of 30 units, and cost would be around $180-$190.

A one off custom pulley will be $500-$600. If anybody has an extra pulley they will be willing to send to Unorthodox they can take measurements and see if anything they have is compatible or could be easily modified to fit. I don't have an extra pulley or I would already have one on the way.

So who would be up for an $190 single belt group buy? I doubt we have enough people that have AC and PS removed, but it sure would be nice. On the other hand I think there is a chance we could get 30 triple belt orders, but it would probably take a while.

most of our A/C does not work so i guess the AC part could be taken off. i would be down for a pully.....from my understanding there are two types....underdrive and a lighten pully....or we could use both. i would take off PS...but mine works just fine.

[2oodoor]

Is this fab pulley already outfitted with sensor ring?
How are they going to know where we want it unless they have one?
We are still talking about a universal wheel ring that could be used with a homemade stand alone ign.? or some others for like an Escort for example?

(dam Im not being an askhole am I? ..)

[bobafett]

https://www.3geez.com/forum/showthread.php?t=60784

Yes there are 2 basic types of pulleys, stock diameter, and underdriven pulleys, which i believe are larger than stock diameter and turn the accessories at a slower rate which produces less parasitic drag. Both versions would be made from aluminum and be significantly lighter than the stock pulley. Beyond that you can get a pulley that doesnt have the bulk of being able to accept belts for the pesky AC and PS that we have already disabled.

And no, this pulley would not be modded for a trigger wheel, its just an off the shelf boring crank pulley. However, electromotive sold a kit for B motors where they took an unorthodox pulley, modded it to accept their trigger wheel goodies, and sold it as a standalone part. It is my assumption that we would have to do that work ourselves, or have machine shop do it. From what I have gathered from my machine shop, its pretty easy, and not all that expensive, the tricky part is making sure the gap in the teeth is oriented in the right place, and making sure the trigger wheel is mounted in a place where you will be able to get a sensor near it. I think the outer part of the pulley is our only chance, because we have the lower timing cover to contend with on the inside edge.

[carotman]

Since the diameter on the B series pulley is bigger, you could have a bushing pressed in to reduce the size to 25mm. Just a thought here. I'm sure you won't find more than 5 people willing to buy underdrive pulleys here...

[bobafett]

Yeah, we need to send them a stock pulley to see if the offset is anywhere close though. I guess its time to look through all my old parts. Don't think I have one though. Somebody might have an extra they can spare for a little while though, hint hint wink wink! jk

[2ndGenGuy]

Doesn't the crank pulley double as a harmonic balancer? So if you take that weight away, won't you potentially destroy the bearings in an unbalanced engine? I mean, if you do this mod, wouldn't you want to make sure your bottom end was balanced first? I know the crank pulley on my ES2 has been balanced, it looks like, and I'm guessing it counter-balances the crank...

Also, isn't an underdriven pulley smaller at the crank? Less belt movement around the crank = less belt movement = slower accessory, no? I think if you underdrive the accessory itself, and leave the crank pulley stock size, then the bigger pulley goes on the accessory itself.

[bobafett]

You are right, I was thinking backwards. The accessory pulley would be bigger to be underdriven, but the crank pulley itself would be smaller.

As for the Harmonic Balacing properties of an a20 crank pulley, I am not sure. Jason (accord epicenter) just brought that up in the group buy thread too.

I honestly never thought they were, but if its a non-issue with a balanced motor I am not concerned lol. My setup is very very carefully balanced, also the JDM pulley certainly doesn't look like it would have any harmonic balancing properties.

It will be interesting to see what comes of this discussion.

[cygnus x-1]

A20 pulleys are all steel (or maybe cast iron?) so they would have no damping characteristics other than added mass. And even that is insignificant compared to the weight of the flywheel.

I have another idea. Take a stock A20 3-belt pulley, cut off the AC pulley, then notch the PS pulley so that it can act as the trigger ring. Or even better, cut off the AC and PS pulleys and cut slots in the middle of the alt. pulley for the sensor to trigger from.

C|

[bobafett]

I think the diameter of the trigger wheel need to be larger than that. the larger it is, the more teeth you can have, which means a finer resolution. my machinist who is a big time racer guy says 8 inches should be good if we can fit something that sized down there. otherwise go as big as you can.

[88Accord-DX]

I was just curious, where you going to bolt this sensor to read the toothed pulley?

[cygnus x-1]

I think the diameter of the trigger wheel need to be larger than that. the larger it is, the more teeth you can have, which means a finer resolution. my machinist who is a big time racer guy says 8 inches should be good if we can fit something that sized down there. otherwise go as big as you can.

That big? How much resolution is needed? How about just reading from the teeth on the flywheel?

C|

[bobafett]

don't think you would be able to get a pickup sensor close enough, plus there is no missing tooth on the flywheel.