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914World.com _ 914World Garage _ fan belt problems
Posted by: jat914 Dec 15 2019, 02:20 PM
I had to replace the fan belt on my race built 2065 motor. The replacement belt is made in China and at high rpms it kept flying off! Has anyone had this problem and is there a solution?
Posted by: rgalla9146 Dec 15 2019, 07:13 PM
It is less likely a counry of origin issue and more likely a hardware problem.
There is a recent thread here concerning belt / alignment / brackets
Posted by: porschetub Dec 17 2019, 02:19 PM
It is less likely a counry of origin issue and more likely a hardware problem.
There is a recent thread here concerning belt / alignment / brackets
I only use Contitech belts because they are very durable and fit well same as I only use OEM oil filters but that's just me.
Make sure your altenator pulley isn't worn and polished up (slippage) ,make sure you check the mounting brackets (as mentioned) ,try to do a basic alignment before tensioning the belt.
Posted by: brant Dec 17 2019, 03:03 PM
Gates makes a belt with ribs on the exterior
It’s is superior to most other belts
There is a trick for high rpm belt slip and racing... but not good for the street and charging. So a better belt is the 1st step
Then check the pulleys or replace would be next
Posted by: sixnotfour Dec 17 2019, 03:38 PM
the new continental/ ContiTech are made in .......white letters since 2014
Posted by: 914Sixer Dec 17 2019, 04:06 PM
Make sure you are using the correct size belt. 9.5 x 965 mm or 021.903.137A
Posted by: jcd914 Dec 17 2019, 04:27 PM
This was a fairly common issue for track use or auto-x drivers since quick RPM changes were common. Even with all the brackets and pulleys in good shape and properly aligned the high RPM could throw the belt just from normal stretch.
On track cars or Auto-x only cars we used to run a narrower belt that fit deeper in the pulley and was less likely to come off at high RPM.
It was a domestic sized belt that I think was 7/16 wide or about 8mm but I am not sure.
These did not have lifespan a belt should have for a street car but they stayed on track/auto-x cars.
I still have an old one but I don't think it has numbers on it anymore.
Jim
Posted by: porschetub Dec 17 2019, 08:18 PM
Make sure you are using the correct size belt. 9.5 x 965 mm or 021.903.137A
9.5 mm are you sure ? I thought it was 10 x 965 ?,2 of my engines have that size belt...not saying you are wrong but TBH have never checked.
Posted by: 914Sixer Dec 18 2019, 06:59 AM
Belt
Attached image(s)
Posted by: cuddy_k Dec 18 2019, 10:18 PM
It is less likely a counry of origin issue and more likely a hardware problem.
There is a recent thread here concerning belt / alignment / brackets
I had a repetitive belt slipping issue. Turned out the alternator pulley was cracked.
Posted by: rhodyguy Dec 19 2019, 11:12 AM
The mount bracket for the alt. My car made a chirping sound when running and I could never get the belt to remain tight.
Posted by: jat914 Dec 19 2019, 02:50 PM
This was a fairly common issue for track use or auto-x drivers since quick RPM changes were common. Even with all the brackets and pulleys in good shape and properly aligned the high RPM could throw the belt just from normal stretch.
On track cars or Auto-x only cars we used to run a narrower belt that fit deeper in the pulley and was less likely to come off at high RPM.
It was a domestic sized belt that I think was 7/16 wide or about 8mm but I am not sure.
These did not have lifespan a belt should have for a street car but they stayed on track/auto-x cars.
I still have an old one but I don't think it has numbers on it anymore.
Jim
I will try a thiner belt (8mm) since the alignment was fine before I started having this problem. Thanks for all of the input.
Posted by: porschetub Dec 20 2019, 02:22 PM
This was a fairly common issue for track use or auto-x drivers since quick RPM changes were common. Even with all the brackets and pulleys in good shape and properly aligned the high RPM could throw the belt just from normal stretch.
On track cars or Auto-x only cars we used to run a narrower belt that fit deeper in the pulley and was less likely to come off at high RPM.
It was a domestic sized belt that I think was 7/16 wide or about 8mm but I am not sure.
These did not have lifespan a belt should have for a street car but they stayed on track/auto-x cars.
I still have an old one but I don't think it has numbers on it anymore.
Jim
I will try a thiner belt (8mm) since the alignment was fine before I started having this problem. Thanks for all of the input.
After Marks comment about belt size I checked my supply and also found an 8 X 965mm,tryed it on my spare T4 motor (next build) and as Jim mentioned it fitted better in the grooves ,and was level with the top of both pulleys,even being a bit worn the adjustment was about centre on my altenator top bracket
Considering any part of the belt not fully contacting the pulley vee's is lost drive ,perhaps the narrower belt is the way to go.
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