Sprint Chain and Tensioner - again…

[Bish]

Hello good people.

I have been investigating a noise from the top end on my Sprint engine which I thought could be one of the usual suspects; the timing chain, and or tensioner, Jack shaft bearing, valve clearances etc etc.

I had found an invoice in the cars history file for a timing chain and tensioner replacement in 2002 so thought that maybe the Rolon tensioner had given up the ghost. A bit of spannering today revealed this….






Not much to see here then! I guess I could maybe change the chain and tensioner whilst I’m in there, but it looks to be ok. Would it be foolish to leave it as it is now I’ve got this far? Maybe I could adjust the curved guide to take up a bit of slack and reset the tensioner? When did the Rolon tensioner start to have issues with the slipper pad detaching? I’m over thinking it as usual. I’m sure it’s not the source of the noise anyway!

With regard to the Jack shaft bearing play issues - I guess I need to take the chain off to check for play? Is that fore and aft or sideways play I wonder?

The valve clearances are all good. Oil is evidently getting to the top end of the engine, so no problem there.

One thing I really don’t like is that someone has used black silicon to seal gaskets on the sump, timing cover, and cam cover. I’ve dropped the sump to find a lot of goo in the bottom. Like I say oil is getting to the top of the engine but I may as well take the pump off and have a look to check it’s not full of silicon. Thing is, the car did the RBRR last year so I’m sure if there was any oil starvation it would have caused issues before now!?



Any advice appreciated

[Bish]

Thinking about it a bit further.. I still have an original tensioner and guides that came off of VYK when I did that timing chain. They’re in decent, reusable condition. That’s the reynold slipper pad pictured below. The guides are in the same lightly scored condition. So I could use them and get a new chain. Has anyone had any experience with the German made pre stretched chains that Jigsaw racing sell?



Also looking at the photo now, those teeth on the Jack shaft sprocket look like they’ve been sharpened!? Possibly an indication that the shaft has play?

Cheers, Bish.

[xvivalve]

The Rolon tensioners started giving way from around 2010 onwards, well, that's when mine failed on the way back from TDCIR, but it was fitted to the engine in early 2009. Your's may well therefore pre-date the issue.

Personally, whilst you have it apart to the extent you have, I'd replace it either with the Reynolds one you have, or for £38.50 I can send you the OE BL produced MGB style slipper pad and a Rolon body with the necessary blanking plug to release the tension with allen key rather than the press and release as standard. Either way, you'll not be left worrying.

[Bish]

Thanks for the reply, and the offer Alun.

To be honest the Rolon tensioner that’s fitted looks to be fine. I’m sure it would have given up the ghost by now if it was going to…. But that said, I think I’ll use the Reynold tensioner that I have because that has the oil way in the body and oil hole on the slipper. I’ll also use the original guides that I have in stock. But, I will invest in a pre stretched chain from jigsaw / lemans to replace the Rolon chain. That’ll give me peace of mind.

[BobM]

A noise at the top end. Just make sure the camshaft sprocket has not become loose.
Just a thought.

BobM

[Bish]

A noise at the top end. Just make sure the camshaft sprocket has not become loose.
Just a thought.

BobM

Yeah, thanks for the pointer Bob. I’ll go through everything I can get my hands on, now that the cam and timing covers are off and check all is as it should be.

[Robert 352]

I am intrigued by the comment you have made regarding the replacement of the timing chain in one which has been “pre-stretched”. Chains of the type used on the Sprint don’t in my opinion stretch as such but they do wear and in doing so become a little longer. As they do, the measurement link to link enlarges and the chain as it passes around the pulleys rides further up the teeth.

So what is this pre-stretched chain? Is it a chain which has been run momentarily to allow the links, pins and rollers, to bed in after manufacture? In which case the chain which I can see in the photos looks to be very nicely bedded in. And that is evident by the photo of the position of the Rolon tensioner.

By all means take that chain off and check its wear by checking the side to side movement which is the technique we have always used to check for chain wear. Look also at the surfaces of the crank pulley and see whether the chain is bottoming or whether it is riding a little further up the sprocket.

You have clearly satisfied yourself that it is neither the tensioner nor the faces of the guides which have worn prematurely. I would be inclined to bolt it all back together using not the black silicon sealer which was used previously but one of the more modern sealants, in a very sparing fashion.

The last time I had a top end rattle in a Sprint engine it turned out to be a broken valve spring, Something which we regard as a very rare occurrence but which can and does happen.

If you really want a “pre-stretched” chain then I am sure I could find one and donate it to the cause. It would have been fitted to an engine which ran about 200,000 miles before it was changed. I am not sure that I kept the sprockets!

Robert

[Bish]

Hi Robert thanks for the reply, and the pointers on checking the sprockets to see how the chain is running.

I’m just conscious that the Rolon branded parts are crap, and so have looked for replacements.The Reynold tensioner that I have in stock will do that job. Whilst looking for a chain I came across the German made pre stretched chains sold by lemans. Apparently long lengths of chain are stretched and then made into individual timing chains. The logic of that, to me at least, says that I can fit the chain and forget about it for a long while, because the tensioner won’t have to move very far to take up any slack. Also the Rolon chain that’s fitted is definitely slack along the straight guide. Whether that is the source of the noise I don’t know but the fact that I will have quality parts fitted will give me confidence. The chain has cost £70 so I’m happy with that as a price for peace of mind.

[sprint95m]

So what is this pre-stretched chain?

Good to see you back on here Robert.

To only partly answer your question, they (German made) pre-stretched were sold for slant four engines
in both simplex and duplex versions as an alternative to the original.

I have no experience of either pre-stretched but remember the much missed former forum contributor
John (JPB) advised against their use because they snap without warning, albeit at huge mileage,
whereas the original versions would give an audible early warning.
If I remember correctly, John informed us his first 1850 did 180K on its original chain.
To my way of thinking, what was good enough for John is definitely better than good enough for me .


Thanks
Ian

[Bish]

Basically though…. You pays your money and take your choice!

I plan on keeping this car so may be able to report back in a few years……