Hydraulic tensioner question

[Scargo2]

While working on setting cam timing, I dislodged a part on the hydraulic tensioner.
There what looks to be a check valve on top.
There is a ball bearing, a spring and a metal piece that is supposed to hold them in. I’m guessing it is used to bleed air out of the system. It appears I lost one spring. I found a similar one in a small engine carb that look like it will fit, but I don’t know how critical the tension is. Anybody have any experience in this area?

[Lyndon302]

I would be more worried where the spring went .
Lyndon

[Flat6pac]

Too much riding on the part.
Find a replacement for it.
Bruce

[Scargo2]

Our host does not have a tensioner rebuild kit for the oil fed tensioners, nor does anybody else.

[Walt Fricke]

The problem is not so much the spring but the "hat" which holds the spring in place. I gather you retrieved that? It is pressed in place, and chances are it has lost some of its sideways spring force, which is what holds it in place.

I used a very small Dremel diamond coated bit to cut a circular channel in the tensioner body - in the hole. This allowed the hat's several feet to expand into this groove. Worked fine, though I had the original spring.

The ball and spring are a pressure relief valve, since the oil pressure is only used to keep the space below the piston filled with oil. A little comes out each time the piston is compressed, and when it rises back up oil needs to come into that chamber to keep it full so the tensioner can serve its shock absorber function.

I'd not be worried about the spring being down in the oil in the sump. It won't fit though the oil pump screen, and it is out of the way of other moving parts.

[Scargo2]

Thanks. I hadn’t thought of cutting a groove. I have had some success of spreading the feet of the hat to make it fairly tight. I was thinking maybe a tacking in with some JB weld, but don’t know if it will last in that hot oily environment.

[Walt Fricke]

Some contributor to this forum measured the opening pressure of this relief valve! I forget what it was (a diligent search in the fulsome chain tensioner discussions should find it), but having oil pressure of, say, 60-75 psi, on occasion isn't unusual. If the valve opens a 30 psi, does that mean another 30 psi is pushing on it? Me, I am amazed that the production method of jamming that "hat" in there works - engineers are always looking for more efficient production methods.

It is occasionally ham handed owners like me, and I guess you, who cause this problem. If new "hats" were available, all sharp edged and spread out, with some kind of insertion tool, repair might just be straight forward.

Adhesives can do amazing things. Body panels bonded on? I am dubious about epoxies working in this application, though - very little surface area for bonding. Some mechanical fix would seem better. Maybe there is a clever way to construct a collar (which would still let the oil out) to clamp or be riveted or bolted to the sides of the tensioner).

Can you buy new ones as singletons? My experience was with the kit to convert to this style.

[Trackrash]

Originally Posted by Scargo2

Thanks. I hadn’t thought of cutting a groove. I have had some success of spreading the feet of the hat to make it fairly tight. I was thinking maybe a tacking in with some JB weld, but don’t know if it will last in that hot oily environment.

Get a new tensioner. AHIK Trust me you are wasting your time trying to fix it.

Yes you can buy just the tensioner. At least I did a couple of years ago. Do a web search. BTW, make sure you get an OE tensioner.

[Scargo2]

Originally Posted by Scargo2

Thanks. I hadn’t thought of cutting a groove. I have had some success of spreading the feet of the hat to make it fairly tight. I was thinking maybe a tacking in with some JB weld, but don’t know if it will last in that hot oily environment.

I tried to cut a groove, but either I had the wrong bit or couldn’t get the angle right. Once I got a groove, I tried to get the hat to hold, unsuccessful. I am making a part to replace the hat and ordered a variety of springs to try to repair. I will post results successful or not.

[Trackrash]

It may work for a while. Here was my try. read all about it. Carrera tensioner questions

For $350, it is not worth taking the risk.

[Walt Fricke]

Here is what Gordon did. Looks like a worthwhile and permanent solution to me, but one could devise a number of more complicated, but perhaps stronger, ways of holding the "hat" piece in.

When you look at Gordon't amended tensioner diagram, you realize how small the inlet restricter is, and coupled with the low cracking pressure of the relief valve, the force acting on the hat - holding the 4 psi or so spring force - can't be that great. Yes, it can be enough to spit out the assembly if you have somehow knocked it out and just pushed it back in and crossed your fingers.

But it doesn't seem that these relief valves spontaneously spit out. They just need some retention help if you try to reinstall them. I have it in mind to drill and use a piece of stiff wire before I reinstall the one I fixed. Why not a belt and suspenders after blundering?

[Scargo2]

I saw the stiff wire holding the hat in, but as I mentioned above I broke off one of the legs of the hat. So I made a solid steel hat out of 24 gauge (.239”). I only had hand tools- cordless drill, 4” grinder. Top small hole matches top of hat. Counter bored bottom hole to approximate depth of hat (about .150). Then I used 1/16” tension pins to hold them in. The other problems was the lost springs. I found a company that specialized in small compression springs. With a minimum order of 5 springs of each size, and $25 minimum. I ordered 5 different springs with specs close to what I measured on the factory spring. There wasn’t a perfect match, but I choose to go a notch stronger than stock (.001” thicker wire). I installed in both tensioners so they would be the same. So here’s hoping it will work normally. I’ll update when engine is running and if works give spring part number.

[Walt Fricke]

Looks good.

A tension pin is a thin steel pin just a bit larger in diameter than the holes you drilled for them in the tensioner? Fits into slightly larger holes or recesses in the large round piece when tapped into place, and can be seen sticking out a bit in the photos? Could be removed with pliers or vice grips if needed?

I knew there would be a variety of ways of dealing with this issue.

If the standard understanding of tensioner functioning is correct - that the function of the oil pressure is simply to keep the reservoir full - small differences in spring/cracking pressure ought not to matter much.

Congratulations for being able to make a pretty good circle with a grinder.

What, just for grins, spec did you measure for the stock spring you took out of the good tensioner?

[Scargo2]

Tension pins or spring pins, yes, 1/16” drill, the pin is about .003” larger and pinches together as driven in. I tried to cut them off long enough that I could get them out if I needed to, with pliers.
I got the circle shaped by drilling the center hole first, then cut a square, nipped the corners off, then clamped the drill bit in a vise, put the crude octagon steel disk on the drill bit and touched the grinder on it to spin it. A make shift lathe.
The original spring measured, .145” diameter, .393” length, made of .007” wire, 15 coils, closed ends.
No perfect replacement was found of the 5 sizes I bought, two looked the best. They rate them by lbs./in. The two that looked best were rated at .2 and .3. I went with the .3 which used .008” wire. The .2 rated spring used .007” wire, but was a little smaller in diameter. I figured a little higher pressure release was better than lower. It is still very light pressure with your finger.
Anyway thanks for your feedback.