Can someone tell me if there is a difference between the FWD crank pulley and the RWD crank pulley. I understand that our 2.8's are externally balanced, but I also understand that the flywheel/flexplate is where the balancing takes place. I am trying to convert my stock 2.8 to DIS and several of the other mods associated with the 7730 ecm swap. I want to get this all working fine while I build my (3.4, 3400,3500...decisions, decisions). The only crank trigger I have found for a reasonable price only works on the FWD crank pulleys. Can they be interchanged? Am I up the proverbial creek without a paddle? Should I sign myself in to the place with the rubber-walled rooms? HELP

The harmonic balancers are all neutrally balanced. However, some of them have a 3-bolt pattern for the crank pulley and others 4-bolt.. so you may not be able to get a properly spaced pulley for the one you get. I wish I could help you further than that..

If it wasn't raining cats and dogs I'd go look. I have both RWD and FWD 2.8L engines.

Correct me if I'm wrong but isn't the Fiero engine the same layout as the FWD engines? The starter is on the FWD side, etc.

[This message has been edited by Hudini (edited 01-29-2008).]

That's what I thought. I don't understand what the difference could be (the crank trigger attaches using the center pulley bolt) unless it is an offset issue.

How is the trigger indexed? The front wheel drive and rear wheel drive cranks are indexed the same but the dampener has the timing mark groove on the other side because in front wheel drive cars the mark is viewed from what would be the passenger compartment of the Fiero. It seems that the indexing is most important than how you get there.

JazzMan

It is hard to tell that from this site:

http://www.tcemotorsports.com/

I will have to ask these people. It appears that there is one set of "notches" that is doubled as apposed to the other single "notches". I will also try asking on the 60* V6 site because I believe there are people that have used these.

Anyone else with more information?

are you doing this with an old 2.8 crank & block?

the DIS module expects a 7 pulse trigger - 6 being 60* apart, and 1 being 10* off of TDC #1
I dunno what the FWD crank trigger is setup as - but I think it has many more triggers. this is usualy the high resolution trigger, and is used for SPFI, not the DIS.

and, next - I dont see why the pulley matters - I expect you can use either one.

but - what you are looking for is: a metal ring/collar, which has 7 holes in it, 6 equally spaced, and 1 spaced real close to another one. this ring will fit on the crank pulley, held aligned by the key on the crank, so that the 2 close together holes line up, so they are lined up with the pickup @ TDC #1 & 10 degrees BTDC

Yes, I am planning (in the beginning anyway) to use my original 2.8 to get everything up and running with my 7730 ecm swap. This will give me time to really "build" my 3.4 the way I want (like the road-course small blocks I used to build for our local racers). Did you look at the link I posted above? The trigger they sell looks exactly like you described, but appears to mount in front of the damper (what they are calling a pulley) and behind the crank pulley. I am hoping for a rely from them soon, this might help out others that want to convert their 2.8's to DIS and the 7730 ecm.

The only thing I can see from the site is that the damper / serp. crank pulley is all together and we have an extra pulley (V-belt) on the front to drive the A/C? Gosh, I can't remember if we do or not....I just had a brain fart!

[This message has been edited by rjblaze (edited 02-04-2008).]

yeah - that looks like it will work just fine.

ideally, you'd want it "keyed" on the crank - but - this pushes everything else forward, and un-aligns your belts.
probably the easiest thing would be to mount it last - like that first pic on that site. the most important part is to align the pickup at TDC#1.

it also looks like they use a dowel/dummy shaft to carry the key forward - maybe they can make one to a custom length for you, with an extra long crank bolt.

The guy sent me pics comparing the FWD / RWD pulley setup. It appears that since our crank pulley bolts to the front of the damper and the FWD crank pulley / damper are one unit (serp belt rides on damper), that we cannot use this current arrangement.

Do you think a FWD damper (steps inn) could be swapped onto our 2.8's and this trigger be sandwiched between our pulley and the damper? Our damper appears to stick out too far (steps out) to allow this in our normal arrangement.

Does anyone have good pics of our lower pulley (or entire front drive) arrangement?

[This message has been edited by rjblaze (edited 02-05-2008).]

not sure. I expect either dampner is neutrally balanced, so that wont matter.
you wont need timing marks anymore, so that wont matter.
sounds like a "yes". just keep your belt pulleys aligned.

maybe, just go stock, sandwhich it, and then add a spacer on the waterpump pulley & alt pulley of the same thickness.

or have the thickness of the reluctor ring machined off the dampner

I thought about that too. I believe the difference in the face of the two dampers is that the three "spokes" that have the pulley mounting holes "sticks out" on our damper and are "recessed" on the FWD damper/pulley. I still have not found a good pic of our damper by itself to be sure. You just might have hit the nail on the head!.

in order for the crank trigger to work, the ring must protrude from the dampner enough, so the pickup senses the holes.

anyways - it does look like that ring & pickup can be made to work - one way or another.

Does this help?





JazzMan

[This message has been edited by JazzMan (edited 02-06-2008).]

Jazz....you are da' Man! Thanks a bunch! Those pics definitely help a bunch. Now hopefully the trigger wheel is large enough in diameter! You wouldn't happen to know the actually diameter of our damper, would you?

Not a clue, but if I can find on in my spares tonight I can measure one for you. Will post back tomorrow.

JazzMan

thx

Any luck Jazz?

bump ^^^^^^^^

Both HB from the 3.4 RWD and 2.8 are the same diameter. both belt pulleys are the same diameter, where they differ is configuration for belt type. they don't appear to interchangeable.

[This message has been edited by mswenson289 (edited 02-17-2008).]

I am trying to compare the 2.8 / 3.4 RWD type damper and pulley we use on the Fiero to a 2.8 / 3.1 / 3400 FWD combo damper/pulley arrangement. Thanks for the input.

I just measured the HB at 6 3/8" and the Fiero pulley at 6 9/16" (outside edge to outside edge). Used a tape measure so it's not perfect.

[This message has been edited by Hudini (edited 02-17-2008).]

Thanks Hudini. The HB you measured was the one we have for the Fiero, right? Now all I need is to get a measurement for is the HB for a FWD 60* V6. I guess another trip to the pick'n'pull. I really want to get this crank trigger / sensor to work for the DIS conversion!

Sorry, I missed this thread and forgot to post back. I couldn't find one in my spares to measure. Thanks, Hudini, for getting that info!

JazzMan

If the reluctor wheel needs to be modified or a new one made, I could do it. Just need some info on what needs to be done. I'm also trying to get DIS on my stock 2.8. Or if spacers for the pulleys need to be made.

Anyone have some more incite on this?