• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Timing chain tensioner question

Share this page

John Loftus

John Loftus

Darth Vader
Offline
Where the original BJ7 tensioner bolts to the block there is a dowel pin looking part (fitted into the block) that has a small oil hole. The tensioner part has an open bore that corresponds with the pin. Pretty obvious that the oil comes through the small hole and provides pressure to tension the chain.

Problem is, the new tensioner does not have the open bore. Instead it only has a small hole and it does not line up exactly with the small hole on the dowel pin.

Do I need to modify the new tensioner by milling a step bore or open bore? Or is the solution to pull the 'dowel pin' in the block?

Cheers,
John
 
Hi John, Never had that problem. However, I would open up the bore restoring the interfaces as originally designed.---Keoke--?
 
Hi Keoke, /bcforum/images/%%GRAEMLIN_URL%%/savewave.gif

Yes, it's strange. The new part has no bore but a small slightly offset hole. I may need to take it up with the vendor.

Cheers,
John
 
Hi John, /bcforum/images/%%GRAEMLIN_URL%%/iagree.gif I would "take it out" on somebody no sense in having to rebuild the part to make it work!---Keoke- /bcforum/images/%%GRAEMLIN_URL%%/sick.gif
 
And, if you use any gasket sealant, use it very sparingly so as to not seal the hole(s).
 
Thanks for the reminder Randy. Along with the gasket there is a thicker shim used between the tensioner and the block. The 'dowel pin' stands proud just a bit from the shim and appears to seal and locate with the bore. The small hole on 'dowel pin' appears to have been smeared a bit from attempts to remove it by the engine guy. If anyone know what the hole size should be that would be useful info. Otherwise will clean up with the same size hole that is on the new tensioner.

o.k. finally found a program that would let me get the photos of my phone camera so here are a few that show the parts.

block.jpg


tensioner.jpg
 
The tensioner body on the right looks like the latest issue for XK engines. See if it was manufactured in France. The original tensioner for a 3000 engine has a dowel with a very small oil pressure hole. I find MGA/B style tensioners in big Healey engines on occasion and they are usually prematurely worn. (MGA/B tensioners have a much larger oil pressure hole)
It looks as if the dowel of your original tensioner is stuck in the front plate.
I think the XK style tensioner would work better than an MGB tensioner but I would try to find the correct part if possible. Maybe use the Healey dowel in an MGB tensioner if there is no other choice.

Alan T
 
Hi Alan,

The tensioner was bought from Moss several years ago, supposedly for a 3000 motor.

If the dowel is removed from the front plate then the tensioner body on the right should work, correct?
 
John,
I would use it. Jaguar XK engines now use the one without the dowel and those engines have a lot more timing chain than the 3000 engine.
Alan T
 
Alan,

Sounds good. The engine guy has or can get a dowel pin puller. I'm heading out of the country today and didn't want him to push this motor to the side waiting for a decision. Thanks for your quick help! /bcforum/images/%%GRAEMLIN_URL%%/cheers.gif

Cheers,
John
 
FYI. I received this info from Doug Reid:

The new cheapo reproduction tensioners lack the drilled dowel,
but a real one still has it. Insist on Rolon or Renold brand. I got one from Healey Surgeons this spring. They are also used on Rovers and MGBs, so a Land Rover dealership could probably supply one, too.
regards,
Doug Reid, 18G Motorworks

He followed up to say he thinks the dowel type is stronger so he always uses that type.

He also made the suggestion of removing the front plate if necessary to tap out the broken off dowel. But in our case, even though the dowel is quite stuck I think we can get it out with a bit more effort. /bcforum/images/%%GRAEMLIN_URL%%/hammer.gif

Cheers,
John (greetings from Shanghai)
 
I do not agree with the above. I now have NOS tensioners in British Leyland boxes in front of me. The correct part # for the Healey is 37H7330. It does have the dowel and small oil pressure hole (about 1/32"). The MGB tensioner 12H3292 is identical except it has a 1/8" oil pressure hole. The latest issue from Jaguar is part # EAC3629 and has no dowel and small oil pressure hole. Moss lists this part # for the 3000 engine. (Their # 011-139) If this Jaguar tensioner can stand up to 182 links of chain,two cams,five gears,and four guides , it surely can handle the 3000 timing gears. I do not know about the 'el cheapo' tensioner. I buy mine ten at a time from the Jaguar dealer and all have been Reynolds (France)tensioners.............so far.

Alan T
 
Alan,

Thanks for the additional info .. really appreciate it. This new tensioner is the 011-139 and I just checked the Moss site. They list this same part number for the AH100-3000, Jaguar E-Type, Jag XJ6,12, Jag XK and MGB-C which bears out with what you are saying. I'm going ahead with having this new one installed. It seems to be about the same quality as the original and renold sounds a lot like the reynolds brand that Doug mentioned. Maybe there is another type floating around out there that is el-cheapo or 'cheap-cheap' as they say over here in China (as in 'copy watch .. cheap-cheap' BTW, not the best sales presentation to get me interested. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

Cheers,
John
 
Back
Top