help please. gilmer drives

[340i]

hi. im keen to further bling my engine, and the alternator is the only accessory i have. i was thinking of going to a gilmer drive setup for the looks, the whine, and the ease of running a gilmer driven vortech in the future.
but then i read a thread about replacing the crank pulley, and the engine destroying itself, but i have seen this done on roots supercharged engines, so now im confused and not sure what to do.
advice, opinions, etc, greatly appreciated.
thanks.

 

[jibby]

I checked your profile, and wow you have a lexus motor in a BMW, wild!!!! I would love to see a picture of that. In regards to your post I am confused too, anyone?

 

[Zuffen]

The harmonic balancer is designed specifically for the 1UZ to stop the crankshaft flexing between the crank pulley and no1 cylinder. All engines have this problem so it isn't a unique 1UZ thing.

The only way you could do it that I see is to run a "bowl" pulley.

What you would do is manufacture a pulley that could be mounted inside the existing crank pulley then curl up over the ribbed section the serpentine belt runs on. Does that make sense?

This would put the gilmer teeth just above the outside edge of the standard pulley (it couldn't be allowed to touch the outer ring of the standard pulley) and increase the outer pulleys diameter.

Clearance is tight around the crank pulley.

Doing this you would loose the timing marks on the crank as they would be hidden by the gilmer drive.

Another problem is all the ancilliaries would then be overdriven so you may need to make their pulleys larger.

You can't just mount the gilmer drive out the front of the crank pulley like you see Eatons do as the ancilliary pullies wouldn't line up.

 

[340i]

jibby,
see the general discussion page for recent shots of my car.

zuffen,
thanks, i will have to research this more. from looking at the pulley it just looks normal to me, so lucky for people like you stopping me from wrecking my motor.

also, is there a trick to taking the crank pulley off?

 

[jibby]

340i - Sorry I am off the subject but that is a crazy conversion you are trying. First off I am suprised the V8 motor will fit so cleanly under the hood. It looks like a great fit. You must be doing some major welding on this baby? I would guess you welded in the lex motor mount brackets to the BMW sub frame. What about the drive train? More welding I would guess. Did you pull the ECU with the motor, or are you using a programmable? Man, cool project I would love to see the final result, and also what do you expect to accompish in the way of performance? Awesome!!!!! I use to drive a BMW, almost as good and reliable as the Lexus.

 

[Zuffen]

340,

To get the crank pulley off you need to undo the crank bolt. There's a thread on it in the last month or so with some very sound advice. Have look and it's there.

You may need a three legged puller to get the pulley off.

Don't let my post stop you thinking about the idea.

We need people like you to "push the envelope" to make advances happen. Sleep on it.

 

[340i]

jibby,
the engine fits 'ok' but is a mission to get in and out. the tunnel didnt need any work, but the steering column had to be shifted over, and the panels at the front of the engine bay had to be modified. yes i have had alot of welding done. alot... and most the parts in my car have the prefix 'custom-' or 'customised' before them.
im using a link computer, to allow ease of tune, manual conversion, no airflow sensor, no cold start injector or sensor, no emmissions rubbish, etc. basically better performance, and simpler setup. compare my engine bay to the other e21 bmw on the forum and you'll see what i mean.
as for performance, im hoping for high 12's down the quarter, with good drivability and driftability.
back to the subject, if i add a gilmer drive over the crank pulley, will the extra weight unbalance the motor, or should it be sweet?

 

[jibby]

340I- 12's down the quarter, nice, I presume you are going to modify that engine from stock to achieve that time, unless the BMW is really light in weight? Yeah ,I figured you would have to do alot of welding on a conversion like that. What about the drive train and rear end, what are you using, I would guess a lexus/soarer or supra drive train. I don't think you can tie in the bmw drive train to that lexus motor? What about the cooling system, keeping the stock bmw radiator and fan ? No emissions that makes things alot easier and faster, I would think you will make custom headers to fit?. Sounds like it's going to be a one of a kind car, awesome. Keep me posted, I will love to see the finished product.

 

[Cobber]

Gilmer drive has been done to drive the alternator on a cobra replica being built in Perth. I will try to get some better photos next time I am at the workshop. The belt is tensioned by adjusting the altenator. The Gilmer drive pully was machined to fit inside the original pully.

I have positioned my alternator to use the original belt.

 

[340i]

thanks. i might do a gilmer like that.

jibby,
12's is just a guess. iv seen a 1uz on bags do 12's (standard engine) so figure my stripped out bimma would be lighter and similarly paced.
for the drivetrain, the supra box goes to a custom one piece driveshaft, nissan skyline gts25t diff (4.3:1, LSD), and then through custom axles to 17x8 wheels and 235 series tyres.
the radiator is skyline, with a 14" electric fan, switched by the ecu.
the exhaust manifolds are standard ones, modified to clear the steering column and firewall, then heatwrapped.
in the photo you can see how little room there is for the exhaust. it the column has been moved and it still has very little clearance.

in the second photo is how the alternator was, but i had a thicker alloy plate bracket made up to adjust the tension. this setup works ok but the reason i want to go gilmer drive is i need to have the alternator closer to the motor (its too close to the chassis) and cant find a shorter 5 or 6 rib belt, and id like to under drive it a little.

anyone know how much slower i can run the alternator safely?
there is minimum electrics in the car, and i dont intend on running a huge sound system (one amplifier max).

 

[jibby]

Wow, tight fit it looks like, and alot of custom work as well. I guess with the lighter weight 12's is possible. I thought you would definetely need a few mods to achieve a 12 second quarter. Maybe I should start stripping down my sc400, remove the doors, hood, trunk, etc.. then I should really be flying, but I would sure feel a draft up my arss. Anyway, it looks and sounds like you are almost finished. Keep plugging away you will get there.

Wondering, what made you think of doing this conversion with a BMW?

 

[340i]

i wanted a cheap light rear wheel drive, and that normally means something like an old toyota corolla, but i opted for the bimma for something different and it has independant rear end, and my model (323i) came with factory 4 wheel disk brakes (but then i ended up doing all new brakes anyway. lol) and they are quite ugly standard so no-one mods them, but look nice once modified.
i hope to have the only car that is anything like mine in the whole world. i think that is what alot of us on this forum strive to.