[Healeys] Timing Chain Tensioners

Mon Feb 22 14:27:53 MST 2021

When rebuilding the MGA 1622 engine in my former Elva Courier race car I
used an "upgraded" tensioner sourced from Jaguar--apparently same or
similar to the unit of which several folks have spoken.
I did so because it was "cheap insurance" for a part that is difficult to
inspect, the failure of which can have dire results.
I don't know if I made the correct decision because while the new tensioner
worked just fine so too did the "standard" one it replaced.

Best--Michael Oritt

On Mon, Feb 22, 2021 at 3:09 PM m.g.sharp--- via Healeys <
healeys at autox.team.net> wrote:

> The DW tensioner is significantly different from either of the two  that
> Michael is referring to, and substantial more expensive than either.  I did
> some "research" on the web (as a scientist I struggle calling that
> research) when investigating tensioners for my current rebuild and from
> what I can figure out there are at least three tensioners on the market
> that will work.  This same tensioner fits MGBs, Jaguar XK engines and Land
> Rovers, and the majority of chatter on the web is from Jag and MGB owners.
>
> 1.      This is the “base” model which is readily available and is a copy
> of the original part.   The web revealed a number of reports of the rubber
> pad un-bonding or the whole piston popping out.  I suspect the latter must
> be due to a stretched chain allowing the piston to come out too far.  Many
> of the failures of the rubber un-bonding are from racing applications but
> there are a lot from road cars as well.  One English builder who races MGBs
> says that all his failures were on race engines and he thinks failures on
> road cars are very rare, but he is talking of MGBs.   Many reports name the
> manufacturer as “Rolon”, although there could be more than one source of
> this base model.  This is the “base” one that MOSS supplies and you can see
> “Rolon” stamped into the casting in their illustration.  It is $13 USD
> 2.      A French company called Renolds makes an upgraded tensioner that
> is visually similar to the original but apparently has better pad material
> this is the one Mike has illustrated on his post.  I could only find one
> report of the bonding failing on this tensioner.  Reports vary, but it
> seems this part is the OEM Jag replacement available from dealers as part #
> EAC3629.  Some people had reported getting the Rolon part supplied from Jag
> dealers, and one report said both were available as OEM and “upgraded” OEM
> from his Jag dealer.  This is the tensioner sold by MOSS as their “premium”
> tensioner.  It appears available from other sources including Jaguar
> dealerships.  It is $90 USD.
> 3.      The third one is described as a “hydraulic” tensioner.  This is
> the one sold by DW for 130 GBP.  I think that A-H spares sells the same one
> for 90 GBP, but the difference may be the VAT.  The one from DW has “DWR”
> stamped into it, but they may be adding that themselves.  This has a nylon
> slipper and it is narrower than the chain, whereas the other two have
> rubber pads slightly wider than the chain.  I cannot find any reports of
> this type failing, but I did find a report of it being a poor fit.  Oddly,
> the chat lines that had extensive discussion “Rolon” vs “Renolds”, do not
> mention this tensioner at all, so no information on reliability, which
> really means no failures (who takes the front end apart to check the
> tensioner is OK?).  However, I am sure that relatively speaking, very few
> of these have been fitted relative to all the Jag rebuilds using the
> Renolds unit and there are probably 1000s of the Rolon units running in
> MGBs.
>
> Regarding them all being hydraulic, there is a bit of confusion, but
> several sources say that the oil feed is just to lubricate the pad and the
> tension is all provided by the spring.  However the DW one is said to be
> truly hydraulic.  Whether oil pressures assists with tension on the first
> two, or dampens the piston movement caused by oscillations of the chain,
> has been raised as a question, but no definitive answer.
>
> That is the sum total of what I know about timing chain tensioners.  For
> the record, I opted for Moss' "Premium" tensioner (#2 above).
>
> Cheers, Mirek
> '59 BT7
>
>
> -----Original Message-----
> From: Healeys <healeys-bounces at autox.team.net> On Behalf Of Bob Spidell
> Sent: February 22, 2021 12:22 PM
> To: healeys at autox.team.net
> Subject: Re: [Healeys] Timing Chain Tensioners
>
> I can't answer your question definitively, but can say--in hindsight--that
> I wish I'd installed DWM's upgraded tensioner on my BJ8's last overhaul.
> Expensive (relatively), sure, but failure of this part would be
> near-catastrophic, and I've heard anecdotally that aftermarket versions
> have failed (and I have an inherent distrust of any aftermarket part with
> rubber). How much is (relative) peace of mind worth?
>
> I installed DWM's flexible oil pump pipe in my BN2 on DWM's 'advice' and
> I'm glad I did. I know of at least one failure of the original, metal pipe
> (from someone on this list).
>
>
> On 2/22/2021 9:10 AM, Michael Salter via Healeys wrote:
> > I note that the usual suspects all now seem to be selling 2 grades of
> > 6 cylinder timing chain tensioners.
> > As far as I know the more expensive variety, which are 5 times the
> > cost of the less expensive type, are relatively new on the market.
> > They are apparently made in France and come in a Jaguar/ Land Rover
> > package.
> > These are slightly different from the originals in that there is a
> > lubrication hole in the rubber pad that I don't recall seeing on any
> > others that I have used.
> > In my experience until very recently the rubber slippers were not a
> > problem on these tensioners but wear of the piston was pretty common
> > on higher milage ones.
> > My question is are these "Premium " grade tensioners significantly
> > better and are they worth the extra cost?
> >
>
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