Failing Timing belt tensioners vs upgraded valve springs.

[Streamln1]

Doing a tear down and clean up of my engine right now, and after removing the timing belt covers, I noticed that the timing belt tensioner was pushed all the way in, and of course had the typical slack between the front and rear heads, but I did a full rotation manually and the tensioner while moving, never did get back to the 'preset' position when you set it initially.

Heres the deal, I have Ferrea dual springs in my heads, so that puts greater tension on the cams, and I also am running a Gates Kevlar belt. Is anyone on board with me with the opinion that perhaps this added stress is too much for a stock tensioner? I have maybe 10k miles on it, I am of course going to replace it, even though it may not be blown, I believe its getting weak. I can't afford a skipped timing belt.

That being said, I did consider running a solid tensioner, but I do worry about not having the automatic compensation the hydraulic unit does.

Any opinions?

[jake stealth]

I have Brian Crower springs and 272 cams and had a similar experience. The engine lost a little power and found the front intake cam had somehow advanced itself two teeth. Like you, I had a loose timing belt and my thought was along the same lines as yours - the tensioner couldn't handle the extra load as imposed by the stronger springs. My thought is the front cam advanced itself after the engine stopped as the cam "nested" into a place where there was reduced valve spring tension - all because of insufficient spring tension as provided by the auto adjuster.

I then adjusted the tensioner so it is fully compressed - it's now functioning like a solid tensioner. Perhaps a little too tight since there was a little timing belt noise that was not present beforehand, but that noise has been slowly deminishing with miles until it's no longer noticeable.

Have driven the car for over 7,000 miles like this with no problems and this includes top speed runs on the Bonnevile Salt Flats.

I would like to have a damped tensioner with perhaps 2-3 times the normal spring pressure - think it would work better with heavier springs.

Just my thoughts and what I did -

Jake

[Beau_Jester]

"I then adjusted the tensioner so it is fully compressed"

Wouldn't fully compressed be the loosest set point where fully extended applies the most tension to the belt or am I missing something in the translation of your post?

[Jimvr4]

Check how the tensioner pulley is setup. When you put more tension on the belt, the bracket of the tensioner pulley pushes the pin further into the hydraulic tensioner.

[Beau_Jester]

When you adjust the tension pulley with the adjusting tool there are three forces at work: your exertion of force onto the tool, the opposing force of the hydarulic tensioner and the opposing force of the belt. So when you are making the adjustment you are applying pressure onto the belt and the hydraulic tensioner.

After you adjust the position of the tensioner pulley and tighten the bolt, only two opposing forces remain, that of the hydraulic tensioner and the belt.

Now the hydraulic tensioner applies the pressure onto the tensioner pulley which applies pressure onto the belt. As the belt becomes stretched over time, the tension piston extends out of the tensioner to take up the slack. If you push the pin in all the way, it tends not to come out again so you can get belt slack later.

You would be better off just getting a solid adjuster designed for that application.

[keo92stealth]

My car bent valves because of it .. Had bc valve springs and 280 cams .. I went with a solid tensioner after that .. Ask ray p about it . He will tell u all about it..

[donniekak]

The tensioner only takes up the slack in the belt. The only part of the belt that sees more tension based on springs/cams is the section moving clockwise from the front head, waterpump, rear head, and ending at the crankshaft.

[green-lantern]

Glad I read this, if I go with stiffer springs and cams I'll go with a solid tentioner.

[familyMAN]

I haven't seen an issue with DR springs and street cams. Upgraded to some bigger cams and decided to do the washer trick on tensioner just in case and added a little more tension than usual. I would do a solid tensioner and kevlar belt but I have a habit over torquing everything I touch so concerned I would snug it up too tight and do some sort of damage...

[Streamln1]

So is the consensus solid tensioner with Kevlar belt? I do have the gates Kevlar belt that isn't supposed to stretch.

I had no skipped teeth BTW, I expected a little slack between the front and rear heads because that always happens but I don't think the tensioner should be getting fully compressed in either.