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may have found issue on my rebuild

Sno-Surfer

Active member
Also the gas boiled in mine all the time. Sometimes I’d have to let it quit bubbling before I started it.
On the belt, I see you have an alternator. You want to make sure you have the correct backing plate that holds it to the fan shroud. There is a difference in offset between the generator ( which yours originally came with) and the alternator backing plates.
 

Cidertom

Chionophile
GOLD Site Supporter
Also the gas boiled in mine all the time. Sometimes I’d have to let it quit bubbling before I started it.
On the belt, I see you have an alternator. You want to make sure you have the correct backing plate that holds it to the fan shroud. There is a difference in offset between the generator ( which yours originally came with) and the alternator backing plates.


This was a package engine I bought to replace the trashed engine it came with., I never thought to check alignment. Both the original engine and the replacement has alternators.
 

NorCal

New member
Exactly what Sno-surfer said, there is a difference between the backing plates between generator vs. alt, make sure its lined up properly. You also need to have 10 shims in upper pulley, whatever shims you don't need in between pulley you put them on the outside. Very important or the nut will bottom out but pulley still loose. If lined up properly and tensioned you will never throw a belt.
 

Cidertom

Chionophile
GOLD Site Supporter
If lined up properly and tensioned you will never throw a belt.

Tension was checked prior to this trip. Looking at the belt remains, it looks like it came apart. found several chunks in the skid pan. what was still on the pulley was the top surface of the belt.
 

nikos

Active member
Also the gas boiled in mine all the time. Sometimes I’d have to let it quit bubbling before I started it.
On the belt, I see you have an alternator. You want to make sure you have the correct backing plate that holds it to the fan shroud. There is a difference in offset between the generator ( which yours originally came with) and the alternator backing plates.

I think Sno -Surfer is right.
Make sure you have the correct Backing plate on the alternator,..... and take a look if the belt is on parallel way on the fun and the backing plate. ok

Nikos
 

nikos

Active member
Exactly what Sno-surfer said, there is a difference between the backing plates between generator vs. alt, make sure its lined up properly. You also need to have 10 shims in upper pulley, whatever shims you don't need in between pulley you put them on the outside. Very important or the nut will bottom out but pulley still loose. If lined up properly and tensioned you will never throw a belt.

Maybe these fotos will help.

Nikos
 

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JimVT

Bronze Member
GOLD Site Supporter
at our leavenworth events i seen 2 shredded belts. both were at high rpms when they failed.
 

Cidertom

Chionophile
GOLD Site Supporter
at our leavenworth events i seen 2 shredded belts. both were at high rpms when they failed.


After much thought, I am leaning to the following scenario:
Cat sits most of 3 years with only the occasional ( like 2)low rpm run. belt is taking a set where it is wrapped for long periods of time motionless and tight. First real run this year was short and slow, mostly to check for binding and track belt tension. Then I really try to run her. Not red-line rpm, but near. Not for 5-10 minutes but for most of hour. belt separates and that's that. The cords in the belt were missing most of the rest of the belt.

Checked tonight: pulley alignment: Center line of the two pulleys off about 2 mm. With vw's method of tensioning, that has to happen as the cl of the alternator pulley shifts with the shim stack. Both the damper and alt pulley are parallel. Alt pulley tight on shaft with no movement.

I will provide pix of mounting as I pull it just to check, I couldn't get good photo tonight

When I had her running before meow#1 I found that on hard pulls, keeping the rpm's way up kept the temp well within reasonable range. That engine speed may have been my undoing. I will see what the racing crowd uses for buggies/baja. Or perhaps I just need to run her more often (that's the idea) and change the belt yearly.

Besides changing the oil, anything else I need to do/check before next run? Can the excess heat affect the valve pushrod gap to where I need to go through them?

One more item for the spares kit. it's light and easy to store and I already had the required tools on board.

Just once I would like everything to just "as easy to drive as a car" rather than the "No Learning Curve Too Steep, No Pockets Too Deep"

CT
 

redsqwrl

Bronze Member
GOLD Site Supporter
Intended as humor......

intervention (Picture a bed sheet with that painted on it and four of your snow cat minded friends looking at you):
in regards to the excess heat affect the valve pushrod gap......

"It is thoughts like that that will keep you on the couch."

These VW engines are about the single most abused engine platform on the planet. run it. if its clattering, rev it higher until the fan sound drowns out the tappet noise, when the fan tips squeal back off just a bit.
Prep:
Put a vice grip, a flat and phillips screw driver in your pocket...... throw a set of points somewhere on the dash and a spare belt (must be used) under the seat......

Stoned hippies drove 100's of thousands of miles in these things and still do today.

Therapy over, "get off the couch and back on the saddle, and what ever you do, have no fun."
 

Cidertom

Chionophile
GOLD Site Supporter
Had to order belt(s) in. No one in the gigantic metropolis of Corvallis had one for sale. Talked to two guys who have sand rails with vw power. Both had experienced the shredding under long high speed runs. "live with it, and keep a spare handy". Neither knew of any special race/high speed belt. There may be better belts though, and this summer I will spend some clock cycles on it. Several of the belt mfg's limit the belt speed to 6500/7000 FPM. My math says I'm pushing over 10000 FPM at max sustained speed. Gates has belts rated to 20000 FPM so that may be an option, providing I can get one to fit.

If they come in I will hit the snow (if any) again Sunday. I will NOT give up.
 

Cidertom

Chionophile
GOLD Site Supporter
I will end this episode of the rebuild. Achieved Silcox Hut On Mt Hood today.
 

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