mech. tensioners

hotrod351 · 01-14-2003, 12:38 PM

i bought a 73t with 140,000 miles on it. the man i purschased it from was the second owner. after he bought it his mach. put mech. tensioners on the motor, that was 20 years ago, so i guessing hes put about 80 or 90,000 ,iles on it with these tensioners without any problems. my question is, how do you set the tension on them. they seem pretty tight now and no noise, but if i rebuild the top end ill have to remove them and would like to reuse them. the only way i can think of adjusting them is to set them fairley tight and see if they make a noise, if they do than i would take up some of the slack but i know i dont want to over set them to tight. im guessing it must be a feel that one aquires to adjust them.

cstreit · cstreit's Garage

I would relace them with that many miles... If you are going to re-use them (NOT recommended) at least get the collars that prevent collapseing

hotrod351 · 01-14-2003, 02:02 PM

i dont think i explained the type of tensioners that i have that good. there are a solid bolt with a lock nut on them, they take the place of the hydl. center that was in the original ones. there isnt any way i can see them failing, they would have to break in half. im just concerned, when i rebuild the top end of the motor, on how to adjust the tension with them/ how tight is to tight. how loose is to loose. ive checked them and they seem pretty tight.

Wayne 962 · Wayne 962's Garage

Jerry Woods does not recommend using these at all. Remove them and replace with hydraulic ones...

Mechancial tensioners should only be used in racing applications, and even then, they are not really a good application...

-Wayne

hotrod351 · 01-14-2003, 04:08 PM

well i never that there not recommended, except from people trying to sell upgrades. ive been told that i could run the stoc one with the case savers attached to them, which is what i my have to do. only because i dont know how to adjust them, which is my original question. id never run the oil feed ones because what happens if the oil pressure drops. i would say that having tensioners with a little spring to them might be better but then these have been on this engine for who knows how long, at least 80,000 miles and maybe a lot more, and without any problems at all. just thought someone might know how to adjust them. one other thing, ive never heard of anyone having them fail.

cstreit · cstreit's Garage

THe solid ones are definitely more for racing and not really appropriate for street cars because of how often they must be adjusted.

hotrod351 · 01-14-2003, 06:04 PM

were getting close. thats my question
, how to adjust them. from your answere, im guessing when they start clicking. as of yet there silent. i didnt bother to ask the previous owner how often he adjusted them and he didnt mention it. i guess ill just have to wait and see. the car only gets driven in the winter, our summers get to 125 degrees, about 300 miles a week. if i do replace them it will be with the stock ones and the savers. i want to thanks everyone who as given an answered to my post. its all food for thought.

Wayne 962 · Wayne 962's Garage

The mechanical tensioners are not advised for any use because of a number of factors:

- They are solid, and typically place too much static tension on the chain
- When the engine heats up, the entire engine expands. Having a constant displacement (instead of a constant force) means that your chain will be stretched and word out quickly. I wouldn't be surprised if your chain is flapping around right now.

You are not making a smart, informed decision with respect to the chain tensioners. The hydraulic ones are much, much more reliable than either the mechanical or spring-loaded ones. The hydraulic tensioners are *not* hydraulically driven, but are instead hydraulically dampened. You can also setup a collar for use on the hydraulic tensioners if you are so worried about it. If the oil pressure drops, then the tensioners will still hold because there is an internal spring to them.

If the oil pressure drops enough for the chain tensioners to stop working, then you have more important problems, like main bearing starvation to worry about.

Your info is suspect here - no one I know recommends using mechanical chain tensioners. If they were so great, then Porsche would have used them in all their cars, and we wouldn't be having this conversation. As for the hydraulic tensioners, it is Porsche's answer to the faulty and dangerous spring-loaded chain tensioners that were responsible for many, many destroyed engines. And the safety devices you are referring to are called 'chain guards' or collars - not 'case savers.'

-Wayne

hotrod351 · 01-15-2003, 09:38 AM

thanks again for the replys. ill be going with the spring loaded tensioners and chain guards when i do a overhall, and no the chains are tight, no noise.

Wayne 962 · Wayne 962's Garage

Just don't use the mechanical chain tensioners...

-Wayne

ersatz · 01-18-2003, 10:13 AM

Replace the chains while you are in there. Those chains have to be suspect from that many miles and from the abuse of the mechanical tensioners. New ones are only about forty bucks each. Good insurance. You'll feel safer with new chains and new tensioners. You'll hate yourself if a chain fails.

Marshall