Crankshaft pulley

#1 08-10-2003, 12:59 AM

Come across a car where the crankshaft pulley has come apart at the seams! The grooved portion has been chewing its way through the timing belt housing.

Question - is there another Subaru that uses the same pulley before? And the replacement presumably needs the timing belt removing.

Thanks guys

Tony

svx_commuter · #2 08-10-2003, 04:50 AM

The crank pulley is an item to watch, so it can be caught before it grinds into the T-belt cover. SVX crank pulley is unique to SVX. Only the ac, ps belts have to come off to change it. T-belt can stay put. Covers for T-belt need to be replaced? It is most likely warped.

Motorsport-SVX · #3 08-13-2003, 12:56 AM

Quote:

Originally posted by svx_commuter
The crank pulley is an item to watch, so it can be caught before it grinds into the T-belt cover. SVX crank pulley is unique to SVX. Only the ac, ps belts have to come off to change it. T-belt can stay put. Covers for T-belt need to be replaced? It is most likely warped.

an underdrive one pcs crank pulley for it if you want......

svx_commuter · #4 08-13-2003, 05:02 AM

With the under drive pulley the ac compressor and Alt will run at a higher rpm. Right?

Why is there a rubber ring in the standard pulley?

CigarJohnny · #5 08-13-2003, 06:21 AM

The drive pully is driven off of the crank. If the pulley is smaller, as in an underdrive, then the accessories turn at a slower speed. That is why they are supposed to increase available HP by slowing down the accessories that siphon the HP from the crank.

I believe there is rubber in the original to absorb crankshaft vibration. Some folks refuse to use an underdrive for the very reason that it will not absorb those stresses and will theoretically shorten the life of the crankshaft. Others disagree that it would.

svx_commuter · #6 08-13-2003, 10:39 AM

Yes your are correct and I should have realized that.

Small is slower.

I do remember reading a thread where the failure was thought to have been caused by the underdrive pulley.

Red Wolf · #7 08-13-2003, 09:56 PM

Depending on who you talk to, the rubber isolator in the crankshaft pulley is either there to absorb vibration or to compensate for crankshaft flex. Though I've never seen it proven, most of the other automotive sites I visit agree that one-piece crankshaft pulleys are bad news.

This is especially true in the 1st and 2nd gen. Mitsubishi Eclipse environment, where the 4g63 engine's crankwalk problem has been partially attributed to the use of one-piece underdrive pulleys.

The theory is basically that the rubber isolator compensates for the crankshaft flex caused by the #1 cylinder firing. Replacing that pulley with a one-piece unit that cannot compensate for the flex causes additional strain and wear on that main / thrust bearing, eventually leading to a crankwalk condition.

However, this is all somewhat anecdotal and I have no idea if it even vaguely applies to the EG33.

John