Mechanical Chain Tensioner, Necessary?
 

Guys,

Is a mechanical chain tensioner really necessary when setting the cam timing on the right side of the engine?

The service manual shows the timing being set with the hydraulic/Carrera, tensioner's installed on both sides of the engine.

Do i really need to purchase two mechanical chain tensioner's?

Should I even bother with the use of vice grips on the left?

Maybe I could even use the old style tensioners I have lying around?

Any input would be appreciated.

Thanks,

Mike.

The cam chains run snug in operation, not tight.
Trying to keep the chains tight during timing is not necessary.
I look for just early of center of the specs when setting cam timing and repeatability.
As the engine runs the chains wear/stretch.
Setting slightly early allows the cam timing to wear into the center of the spec.
I also match both sides, sometimes it may require jumping a chain to get both sides as close as possible.

Mike - when setting timing it is convenient to use something other than the regular tensioner to put tension on the chain while you are measuring things with your dial indicator. Because you will want to release tension when adjusting things.

How you put that tension on is not important. Mechanical tensioners, if you have one lying around, are convenient because you can easily unscrew them back to loose.

But there are dozens of other ways to do this: vice grips, welding clamps, the purpose made screw extenders you can purchase. I used to wedge a short piece of aluminum angle stock, cut to length with some grooving in one end, in to a suitable place in the chain housing to force the idler arm tight.

A small hardware store turnbuckle could easily be modified for this purpose. It is made to pull tension, but will act as a screw jack nicely.

Another way put the bolt in and tighten with the nut pushing against the housing.

http://forums.pelicanparts.com/uploa...1266985026.jpg

Thanks guys,

Once again you exceeded my expectations with your knowledge.

With that being said, I will not pursue the purchase of a mechanical tensioner, marking it on the list of another good tool, but not absolutely necessary for the proper job.

I am in the process of waiting, for my repaired cam (major pitting) and rebuilt rocker arms to arrive, before I start the timing process. (approximately two weeks)

Probably will need more input when that time comes.

Thanks again,

Mike.

I was fortunate to borrow a set of solid tensioners similar to what JB racing sells...

JB Racing - Porsche Engine Componentshttp://forums.pelicanparts.com/uploa...1267030205.jpg

Those are pretty cool HelmetHead, never seen those before.

gotta admit though, I would probably end up putting to much tension, or not enough, because of my lac of experience.
I would probably stretch, my new no link chains. Maybe not.

Thanks,

Mike.

It would be really difficult to stretch the timing chain with too much tension. Chain "stretch" is caused by the parts of the chain wearing over time and creating larger tolerances in the pins and rollers. I just did the cam timing thing and it's not nearly as big of a deal as you might think. I replaced the 930 tensioners with new hydraulic tensioners and simply "unpinned" them while adjusting the cam sprockets. Without oil pressure in them there was not that much tension on the chain and therefore the cams would move without any problems.

Lindy

Lindy,

Since you put it that way. that makes real good sense.
I'm sure once I hurdle this aspect of the project
I will find that it was easier then I had anticipated.
Kinda like the the removal process of the... flywheel bolts, head-studs, you know
Probably nothing to get to worried about. Thanks to this site.

Mike.

You'll be fine. If you need any first hand help let me know. I'm just about to put the motor back in the car this weekend. Still have a couple of weeks before I fire it off waiting on my twin plug dizzy and a few other bits and pieces. Have fun!

Lindy