Sprint timing chain / tensioner help please

[Bish]

Hello good people

I’m tracing top end noises and have whipped the cam cover off today to investigate the chain tension and valve clearances. First thing I notice is the the chain seems slack?

First photo shows the chain lying on the guide. Second shows me able to lift the chain up off the guide by around 5 to 10 mm with a screwdriver! I guess that’s not right!?





You can actually lift the chain up off of the top sprocket a couple of mm, so I’m sure I’m in need of a new chain and tensioner?

All advice gratefully received.

So my next questions are; who sells the Jag, or similar tensioner, and decent quality chain / guides. I’m aware to avoid the Rolon tensioners. I do have a Rolon chain in stock though. Would that be ok to use?

All the best, Bish.

[Mad Mart]

Rolon chain will be fine. Robsport have the rest.

[Bish]

Thanks Mart.

I’ve taken all the valve clearances too which are all in the .3 to .4 range in mm. I guess that’s a bit slack and another contributor to the noises, so therefore needs addressing. But, I’m pondering on whether the valve shims can be changed with the head on? I have seen a couple of threads that suggest it’s possible. But it looks to be a right faff, with no guarantee of not ruining a head gasket. So I may leave that alone as there looks to be no undue wear etc on valve / rocker gear. Unless anyones experience tells me different and that’s something I cant leave as it is?

Cheers, Bish.

[mahony]

I'm no expert but i'm pretty sure you can change valve shims without removing the head ( last time i did it was in the early nineties with head intact ),did you check the workshop manual ? http://www.dollysprint.com/Docs/SPRINT.PDF

[Bish]

Thanks.

I have checked the manual but couldn’t see where it instructs on valve shim replacement with the head in situ. I’ll take another look.

I’ve found this thread https://forum.triumphdolomite.co.uk/vie ... hp?t=14815 which suggests it can be done. Due to the fact that it’s not a good idea to leave the head untorqued for long, I guess I will need a bucket of various shims at the ready if I’m going to attempt this! Trouble is I won’t know exactly what I will need until I get the little fellas out and measure them! Would anyone be able to help me out with a selection of shims on a sale or return basis please?

[Mad Mart]

You can only change the exhaust valve shims with the head in situ. If I loosened the head bolts to be able to do the inlets then I would have to replace the head gasket, but that's just me.

Trouble is I won’t know exactly what I will need until I get the little fellas out and measure them!

Exactly. There are a few of us on here that have a couple of bucket loads of shims and are willing to send you whatever you need (if we have them). Just post in the wanted section.

[xvivalve]

I have a couple of the Jag spec tensioners

[Matt Cotton]

Thanks for posting this Bish. I have exactly the same activity to undertake on SWU next. It too is very rattly.

I've purchased a kit from Robsport and they do state it is an upgraded tensioner in the kit due to known failures.

I will follow with interest and I'd be grateful for any advice.
Best wishes MC.

[Bish]

Hi Alun, sent you a PM.

Hi Matt

The guinea pig eh!?

I’ve stripped out the rad and fan etc from the car. I’m now waiting on a 1 n 1/2 inch socket arriving and I can get the crank pulley off, then the timing cover, to see exactly what’s going on with the chain side of things.

I’m still unsure whether to take the gamble of doing the shims, as best I can, with the head on. I will have a remeasure at some point this week, this time in imperial, to see how loose the valves are, and whether it’s worth the risk / effort.

I’ll report back.

[xvivalve]

The next issue is the chain guides; the rubber coating on the aftermarket now available seems to be too soft and wears rapidly. If your existing ones are not too badly scored, I'd consider re-use...

[Bish]

The next issue is the chain guides; the rubber coating on the aftermarket now available seems to be too soft and wears rapidly. If your existing ones are not too badly scored, I'd consider re-use...

Ok Alun thanks for that. I was about to order guides and gaskets but I’ll leave it until I’ve looked at what’s in situ.

[Bish]

Ok so the socket arrived. Thanks to the forum tip of chocking a breaker bar up under the front chassis leg and blipping the starter to loosen the bolt. Worked a treat!



Once the timing cover was off the full extent of the horror I was expecting became apparent. Er well no .......... not really



Doesn’t look too bad to me? Anyway I stripped it out as there was deffo slack in the chain so I’m convinced it needs replacing. It’s a Renold tensioner so probably an original? The guides look pretty scored so I’ll replace all as a matter of course.

h



I’m hoping to get the parts here and on the car pronto so that I can get a trip to https://thelatebrakeshow.com/kent this Saturday afternoon.

[xvivalve]

Replace if it gives you comfort, but I wouldn't throw those away!

[Bish]

Thanks for the advice Alun. I’ve ordered the guides from Robsport. I’ll check the quality against the originals, then decide which to go with.

[Mad Mart]

It certainly looks like the chain has stretched...quite a bit. If you look at the tensioner it looks like there is about 5-6mm. gap (maybe more). Initially it would have only been about 1-2mm.