The following words and pictures have been extracted from the above thread:

1. I have a Jaguar one (Renold). This one has a small hole on the body and no hole on the slipper pad.

2. The one fitted to my car and removed was a Renold with no locating dowel and no visible hole on the slipper pad. It must have done some mileage before I stripped the engine down with no issues.

3. I also purchased another Renold one a year or so ago, again a Jaguar one. This one has a locating dowel and the slipper pad also has a small hole in it.

4. Have a look at the side of the piston under the slipper pad head. On the ones without the hole in the slipper pad, you should find a very small hole. I suspect this has two purposes. It provides an bleed for the oil feed preventing air locks and also an oil supply to the chain.

5 ..Just out of curiosity I ordered the EAC3629 one from BritshParts and this is what came, they show the part number as superseded (to C37717LG). Its flat on the back with no dowel. Doesn't look too bad though and its says Made in France on the box:

6. Update: Leacy Classics 12H3292 just arrived:

7. Here you go, this is an original 12H3292 it has a dowel and hole in the slipper pad:

8. The other crucial thing with these is how does the ratchet and spring bit work. e.g. if the internal peg breaks off on the ratchet bit then the tensioner will go loose with no oil pressure..... Surely not ...............its not hydraulic, is it? The conclusion was that it was partially hydraulic I think, or should be....and the ratchet stops it rewinding as you your good self pointed out....and convinced us.

9. I purchased a genuine Jaguar tensioner, EAC3629 (Land Rover box, made in France) from SNG, strangely the manufacturer data looks like it's been machined off. Like others that have posted, I found it had no dowel and a large oil feed hole at the back, I was worried this could starve the head of oil so I pulled it apart to look at it's guts. I was very disappointed to find a very small pin hole oil bypass in the shaft, just like the later Renold ones. The 'lube' hole that goes through the rubber pad does not go all the way through the metal at the back. I'm glad I checked this as I'm sure many people buy these tensioners in the hope that their chains would get a direct oil feed, instead it just dumps the oil to the sump. Why on earth would they manufacture it like this, makes no sense to me. I did email SNG but they didn't bother replying. As if I wasn't in a bad enough mood after loosing a valve shim somewhere down my new engine:

10 Thanks. I looked at my options today and bench tested with the front cover off, it's surprising how much oil comes out of that tiny hole in the tensioner shaft. I'm going to use my old Renold tr7 tensioner body (with dowel) and fit the pad from my Renold sprint tensioner. I think the oil will squirt on the chain when it stretches a bit and the slipper moves out, so a hole in the pad isn't essential. At least I have confidence in the Renolds unlike the thing SNG sent me. At least the missing shim didn't make an appearance and cause damage, I'll worry about that later.

11 The hole in the shaft will lube the chain before it makes contact with the slipper, this will happen more and more as the slipper moves out over time as the hole is just behind the slipper pad. Not sure if drilling an extra hole would mean less oil getting to the head, I'll have to work that one out. Having tested by spinning the pump with a drill and seeing a large amount of oil squirting out of the tiny pin hole I would say that the standard Renold setup should be fine.

12 My point about the genuine Jaguar ones was that it's very easy for most of us to see a hole in the pad and just assume that it goes all the way through, how many actually pulled it apart to check before fitting it? However, it does have a pin hole behind the pad just like the Renold one, so if I had fitted one I wouldn't worry, it's probably no better or worse than any of the others available. I wouldn't chance drilling a second hole in the pad though, there's plenty oil there as it is and the head needs it more.

13 Nice. Same as mine but no hole on my pad although mine has the back-plate with limit stopper, which I like for obvious reasons. :) And yes it should splash the chain before it hits the pad, when the chain stretches there will be a kink in it as the tensioner pushes it out, so an oil coating is unavoidable. When I bench tested the engine there was oil spewing out of it just turning over with a battery, so with the engine running the chain must be getting a right soaking.