Recently switched to using a gates blue timing belt and ran into an unusual problem. Maybe its a one off problem but my gut feeling is no there is an issue here.

I have done many timing belts and like to set the tensioner up as close to closed as possible with out being too tight. This way if tensioner fails the belt will have minimum play and not be in threat of timing jump. Over the years I have set a couple too tight, noticed on first test spin. This is immediately noticeable as the belt will have a very distinct whine. This of course is very hard on cams and oil pump. And if left too tight you will loose an oil pump for sure. I always readjust immediately after test run. I have never lost a pump.

I have seen some local shops here loose oil pumps. On one occasion a shop car lost three oil pumps in a row. The first admittedly was due to the belt possibly being set too tight. The following two however were set correctly but the pumps again failed. I bring this car into the picture because he was using a supposedly stronger/better blue gates timing belt.

Now back to my car. After installing the blue belt I noticed when I got on it hard the belt would whine. The whine was very loud. Just like when a belt is set too tight. driving the car at a gentle cruise the whine would go away. I came to the conclusion for some strange reason the belt gets too tight after a fast rev. It wouldnt do it bad after a pull in 4th , but a quick pull in 2nd left a horrible whine. I have never had this problem before and I have never installed a blue belt before. I always felt they were just a waste of money. Now I have a different opinion. if you use or are using one of these listen carefully for this condition. the car received a factory black belt today and the whine is gone. I can only conclude the belt was causing this "too tight after fast rev" condition.

I have few theories on what is happening. The best being that both a kevlar belt and a standard belt during normal operation get tighter during a fast or high rev. This is expected as slack will be created on the tensioner side of the belts path. The tensioners job is of course is to remove this slack. problem is with the blue belt it doesnt stretch as much as a black belt. So when the belt is in a normal over tight state its a problem for the blue kevlar belt because it does not stretch. But not a problem for a black belt which has some stretch to it.

 

more people need to acknowledge and know this. I do a lot of auto services and have never been fond of the the "blue" or kevlar type belts.

I've yet to hear of a properly installed factory belt messing up.

 

up

 

Intresting.. I used stock and hks, and I was planning on getting a gates for my personal car.. HKS kevlar had none of these issues.. I am thinking to just stick with stock now. Thanks for the heads up.

 

Mine doesn't whine... Thats odd. I will keep listening for it though if it does whine. many 8 and 9 sec cars use gates belts though.

 

btw i dont know what you mean by closing the tensioner, but it specifically states in the mitsubishi manual to make sure you can slide the grenade pin in and out of the hydraulic tensioner .... if you cant get the grenade pin through the tensioner you did your timing job wrong. I to have done around 15 belt jobs.

- Add: It sounds to me you overtightened the balance shaft belt, because those are the symptons of a overly tightened BS belt. It will make the car feel like **** and whine.
The BS belt should have major deflection on it.

 

I had gates kevlar belts on my car and had no issues with it.

Sounds more like an issue with your belt tensioner procedures. As tight as you can get it without whining is not real precise. The factory spec is to have 5-10mm of deflection.

I have heard of a few people having issues with Kevlar belts while running stub shafts on the oil pump but, you are opening a whole other can issues there.

 

Who the hell is losing oil pumps by overtightening the belt? Sounds like another issue.

 

The stub shaft will cause the failure.

 

It has happened to dsms in the past.

 

The stub shafts will absolutly not cause the failure. Most often than not the pump is not assembled and lubed properly. Mitsubishi had to back that stub shaft with a warranty when they were putting them in Mirages. The only stub shaft that will cause failure is the TopLine shaft which has no oil feed passage or groove.

 

If you load the shaft axially enough with say oh i don't know maybe improper belt tension it can fail. If properly tensioned it shouldn't but, we are talking about improperly tensioned belts here.

 

glad i went with gates black belt

 

http://www.amsperformance.com/cart/A...mance.com.html


Per AMS website:

In our experience, replacing the front balance shaft with a stub shaft will increase the chances of oil pump failures. This is likely caused by eliminating the support provided by the rear bearing journal.

 

Very good to know. About to do a timing belt on the RS, I will go with the OEM belt. Thanks for the heads up.

bren