Cam chain stretched and need changing?

Smousley1995 · Post by **Smousley1995** » Sun Jan 04, 2015 10:41 am

Hi, I'm pretty sure I know the answer but just wanted to check.
My cam chain tensioner seems to be at the end of its stroke and that would mean its time to change the cam chain right?
Also theres no need to change the tensioner is there if it still works?
Heres a few photos of the tensioner plunger

JamieNeve · Post by **JamieNeve** » Sun Jan 04, 2015 3:17 pm

It does look like your tensioner has reached the end of it's extension period!

Yes this does mean it's time for a new cam chain, and no you don't necessarily need to replace the tensioner. Some people do it for peace of mind, but if you try and push down the plunger, without moving the ratchet and it stays put, it is fine to be reused!

Jamie

Smousley1995 · Post by **Smousley1995** » Sun Jan 04, 2015 4:04 pm

cheers, at least I'm not missing any sun while I'm in the garage then

Post by **banner001** » Sun Jan 04, 2015 4:43 pm

yup that chain needs to go, read Randall guide, it's pretty comprehensive.

Also, you will need to do your valve clearances after changing the cam chain.

Watch out when you put the cam cap covers back on, make sure the oil feed is located on the exhaust side, it's common for people to not locate it and when they tighten the bolts down it breaks...and it's an expensive mistake!

Smousley1995 · Post by **Smousley1995** » Sun Jan 04, 2015 10:07 pm

I was looking at that guide earlier actually.

banner001 wrote: Watch out when you put the cam cap covers back on, make sure the oil feed is located on the exhaust side, it's common for people to not locate it and when they tighten the bolts down it breaks...and it's an expensive mistake!

Haha I made this mistake the first time I ever had the caps off, already done that

banner001 wrote: Also, you will need to do your valve clearances after changing the cam chain.

Just curious as to why I'd need to do re-do the valve clearances?
I understand as the chain stretches, it can advance or retard the timing slightly but I would have thought the valve clearances would remain constant?

Post by **banner001** » Mon Jan 05, 2015 9:56 am

either way, its a 5 minute job, and everything is already exposed anyways, makes sense to check it in my book.

ManxMan · Post by **ManxMan** » Mon Jan 05, 2015 10:51 am

I'm completely confused by this. Can someone explain to me how a worn camchain makes the valve gap clearance smaller. Surely if the timing marks are aligned when measureing the gap is the same regardless of camchain wear.
I underrstand it's a good idea to check gaps when the cover is off annyway to fit new chain but the logic that the gap is reduced by chainwaer is weird

Post by **banner001** » Mon Jan 05, 2015 12:32 pm

ManxMan wrote:I'm completely confused by this. Can someone explain to me how a worn camchain makes the valve gap clearance smaller. Surely if the timing marks are aligned when measureing the gap is the same regardless of camchain wear.
I underrstand it's a good idea to check gaps when the cover is off annyway to fit new chain but the logic that the gap is reduced by chainwaer is weird

yeah i think that was my morning-brain not working fine (first day back at work), even with a stretched chain the valve should be under the base-circle of the cam, and not touching the lobe so the clearance will be the same, i suppose if it was massively off there would be a possibility that your exhaust gap would get smaller as it would be advanced too far (there are 31 pins between timing mark to timing mark, as the chain stretches this distance becomes larger and advances the exhaust, i.e. if the 31 pins=200mm before then after its stretched its now 205mm).

still, its a good idea to check them all.

www.zxrworld.co.uk