Solid chain tensioners?

cstreit · cstreit's Garage

Browsing a website and found these solid chain tensioners... Ummm... If this was all that was required, why didn't Porsche do it? Would have eliminated a number of failures...

Superman · 10-31-2002, 12:21 PM

Those things are going to be very noisy, and they will need to be adjusted very frequently.

Rot 911 · 10-31-2002, 12:59 PM

What Super said.

Bill Verburg · Bill Verburg's Garage

The solid tensioners are ok for a race car that is always warmed up to operating temp before seeing any appreciable revs and that are frequently(like prior to ea. track session) checked by a competant mechanic. The purpose of the tensioners is to take up slack in the chains caused by (among other things) delta T.

The factory did use solid ones on some of the race cars. If you can't afford pressure fed tensioners then the last version of the 930 tensioner w/ a safety collar is the way to go. The collars are important on an interference engine. They saved my bacon on my old '72. When the pressure fed mones came out in '84 they immediately went into my Carrera.

West · 10-31-2002, 03:07 PM

I've be running solid tensioners in my 2 liter since it was rebuilt 3 years ago because of a tensioner failure. I have only adjusted them 3 times, (once a year), and I've put 40k on it! Now, I don't really drive the car in stop and go, but I do drive it probably 8 months out of the year 100 miles a day to work and back on the freeway (70-80 mph). They can be a little noiser @ idle but who cares, they don't make any more noise than normal over 1200 rpm. They won't fail like later model tensioners and mine are just the original tensioner bodies drilled out with screws and lock nuts in them.

sbarrett · 10-31-2002, 03:38 PM

I just replaced my mechanically adjusted solid-type tensioners with Carrera pressure-fed. I was planning on putting on the collars until I took off the covers and saw the mechanical tensioners. I did not realize how noisy my engine used to be...it also runs better for some reason.

It is better to hear the exhaust rumble rather than the chains rattle!

West · 10-31-2002, 04:43 PM

First of all, it they we that noisy, they weren't adjusted correctly. This is my logic behind running them- hydraulic tensioners can collapse, solid's can't. The major difference between race motors and steet motor's is more power and better reliability. No one ever won a race without finishing, and the factory didn't run them without a good reason.

Oldporsche · 05:05 PM

I have solid chain tensioners in my 2.2 E. It has had solid tensioners since it was rebuilt. I really can't say that they were noiser since I have nothing to compare them with. When I installed them, I just adjusted the height to where I thought normal chain tensioners would be working. I never have adjusted them after I put them in. I made a lot of sets of them up for other owners too. I literally have large coffee cans full of early tensioners. I made the solid tensioners by gutting the things and inserting apiece of aluminum turned to fit the interior of the tensioner. This was, in turn, threaded internally and then fitted with an appropriate bolt and locking nut.

I must admit that I have never used them in a motor over 2.4L in size. I took the precaution of never reving the motor while cold. I always warmed up the motor before any auto-x runs, etc.

I do have the pressure fed tensioners in the 2.7 at the moment. I guess if I were competiting on a regular basis, I would probably use the solid tensioners. I would be expecting to be in the motor after each event anyhow.

Good luck,
David Duffield

Jim Richards · 10-31-2002, 05:03 PM

This past summer I was looking at a 73T for sale that had the solid tensioners. It made me a bit uneasy since I never had heard of any using them before that. The engine wasn't overly noisey, as far as I could tell. I wasn't thrilled with the idea of another periodic mechanical adjustment to make, especially since I really didn't know the adjustment criteria.

West · 11-01-2002, 07:06 AM

He's a few questions for you guys. If you install oil fed tensioners on a motor that wasn't designed for them, aren't you diverting oil from your valve train? Will your valve train suffer @ the expense of your tensioners? On later model motors with stock oil fed tensioner did the factory take this into account and run larger lines or a higher volume pump? Has the factory ever come out with a written recommendation that the later model tensioner should be installed on earlier motors?

Jim Richards · 11-01-2002, 07:15 AM

I could be wrong but looking at the small size of the tensioners, I can't imagine this making a significant difference.

West · 11-01-2002, 07:22 AM

I'm looking @ the oil lines, isn't the oil lines diverting 50% of the oil to the tensioner. It's just a T line with the same diameter hose isn't it.

rvanderpyl · rvanderpyl's Garage

Pressure fed tensioners are designed to have a very small, very controlled leak rate to ensure that no air ends up in the piston. They are not spewing oil out like the lubrication system. The fact that they have the same size line is probably more a convenience as far as fitting go than an indication of the amount of oil that is being used.

Mechanical Tensioners have no provision to adjust for the changes in chain length between running cold and hot, nor do they provide any shock absorbing in the case of fast changes in chain speed. The factory may have used them on SOME race cars, but they used hydraulic tensioners on most. And even for LeMans the motors were designed to last the length of the race and no more, the consideration wasn't that the chain drive would last for 100,000 miles, just that it would last the race.

This particular issue has been around as long as the 911, it was constantly being tried as a way of avoiding the tensioner collapse problem. But it introduces it own set of problems. It is still recommended that a street car use the lastest pressure fed tensioners and the updated arms, if you want a little bit of extra security put a set of collars on, although there have been some reports of these breaking and causing problems of their own.

Superman · 11-01-2002, 08:42 AM

The collars do not fit onto the hydraulic tensioners. Hydraulic tensioners have a strong spring that keeps tension on the chain, plus the pressure of the oil when the engine is running. I suppose the spring can break, though I have not heard much about this happening. But as long as they get oil pressure, they will be putting tension onto the chain. I mean, it is virtually impossible for them to stop functioning properly as long as the oil line does not get plugged. I'd say the failure rate for mechanical tensioners is probably about the same as the failure rate of the hydraulic portion of 'Carrera' tensioners. Same principle as your brake system. When was the last time you heard of someone's brake hydraulic system just failing?

Sure, someone is going to say it does happen, but my point is that sudden catastrophic failures of hydraulic systems is rare indeed. Very rare.

Early_S_Man · 11-01-2002, 09:12 AM

The mechanical tensioners are supposed to be adjusted when the engine is HOT ... meaning at normal operating temperature, AND, to do that means you have to be able to remove the muffler from the hot engine in a speedy manner without injuring yourself seriously ... or at least still have reasonably functioning extremities after first aid is administered and bandages are in place!

A relative P-I-T-A for a street car! If you don't have them properly adjusted ... major premature wear can occur on the idler, cam, and intermediate shaft sprockets, as well as the chains, too!