5,0L Gilmer Drive.

[Mando]

Hi Guys,

Could any one running Gilmer Drive on their 5.0L let me know if the pulley on the crank is the same size as the one on the water pump? I bought mine quite a while ago and have been noticing on some cars on this site, the crank pulley is smaller than the water pump pulley. Should they be differant sizes?

Regards.

[EVLCOB]

Hi Mando
Our Vic Pres; should be able to help you on that.

[Tony Cram]

Mando,

I have a Gilmer drive on my 5.0L Cleveland. Crank is largest of three, Water pump is a little smaller and the Alternator is quite a lot smaller. Sizes will vary on how you want to set up cooling system and charging system at different revs.

Things you need to watch out for.....

1. You dont want to have the Water pump pulley too big as you may cavitate cooling water through your system particularly at high revs. Bigger pulley however, gives higher water flow.

2. If the alternator pulley is too small may not get enough charge to your battery if you have a lot of current draw on your system. If it's too big your alternator will be overworked at high revs. Easy check with volt meter when at idle with lots of electronics switched on.

If you want me to measure my pulley's let me know and I will post a further reply. Hope this helps.

TC

[REPTYL]

Tony's point 2, should be the other way round.
The smaller the pulley the faster it will spin and the harder the alt will work.
It's not so much the size of the pulleys but the ratio between them.
The crank will always run at the same speed, so if your crank pulley is smaller the other pulleys will need to be in proportion.

[simon clemens]

just a thought....

If a crank pully was twice the size of an alternator pully, which one of the pullys would be spinning at twice the RPM???

Answer... the Alternator pully!

Is cavertation caused by an under driven water pump pully at high RPM, or an over driven ratio???

Answer... cavertation is the formation of caverties in a fast moving fluid as a result of a pressure drop. Just like the downstreem of propeller blades!

Hmmmm...

[BMK]

Now is that " e = mc2 " or 'For every action there is an equal reaction' aaah both.



Bernie

[Tony Cram]

Mando,

Jason's right I have mixed up the the sizes for both (Must stop drinking that wine!!). Smaller pulleys give you higher speeds. Your water pump should have an optimum pump curve and that may not be at higher speeds.

The Alternator (my apologies) will struggle to charge if you put a pulley too large on it. ie does not spin fast enough.

Sorry for the confusion I should write these replies late at night.

TC

[jasonnichols]

there is a variety of pulleys out there most are of decent design and quality. some have smaller (overall diametre) some same as OEM. I went for the same as OEM and upgraded the water pump at the same time . The Eldelbrock water pump empeller has been designed to stop that cavitation.( plus looks cooler ) and yes its the ratios that determine what speed it all runs at. Interesting point is the pulleys on the water pump and crank are aluminium while the alternator is anodized steel with rubber insert. The guy who designed these says that the alternator is the one that wears out

[Mando]

I think Im on the right track now. It sounds like what Ive got will be OK. Ill find out when its all bolted up. Thanks for the advice.

Regards.

[Ross Newman]

Hi Guys,
Just a question, do you have problems with alternator bearings or water pump seals running Glimmer Drives?

Regards
Ross N

[Aussie Mike]

In theory they should last longer with a gilmer drive. It's the belt tension that kills the bearings. With a toothed belt you shouldn't need to run as much belt tension as you would with a v belt or serpentine setup. The teeth provide the grip rather than the friction of the belt against the sides of the grooves.

Cheers

[Ross Newman]

Thanks Mike

Regards