timing chain repiacement By bigrustysr (Read 2,326 times)

[bigrustysr]

do i need to split case to replace timing chain--if so how to

[Guitarman]

What engine are we talking about?

[Bashan]

Look on the engine board in the Library. There's a post by Alley called the "sneaky chain replacement". That may help but Andy is right, knowing your specific engine would help.

[bigrustysr]

what a dummy i am forgot the most important part---gy6 150--- looked at alleys sneaky chain replacement only works on the 250-- from what i can find out looks like have to split case sure am dreading that

[Bashan]

Never fear! Take a look at the GY6 project. It's not that bad at all. I'm not so sure you couldn't work the chain through the case just like they did on the 250, that's why I posted it. The concept is the same. However, if we have to split the case getting the kickstart gear off is probably the biggest hurdle. Other than that it's not really that bad. Rich

[Deleted]

Since your opening the engine and replacing the chain. while you have the case open its a good idea to replace items such a chain guides, oil pump chain, Valve seals, oil seals, Piston rings. these things are small little items that get worn over the years and benefit from replacing.

[jct842]

I don't remember where I read it but there was a guy who broke the old chain and the new one and fashioned a master link on a gy6. I think it was because of an odd length chain that was not available for an after market head. It was 6 or 7 years ago that I was reading about it. I would be a little careful doing that though.

I don't know why you are replacing the chain but usually by the time it is worn enough to be a problem there are other things that should be changed as some one suggested.

[Guitarman]

If the chain is broken for some reason, the you need to do a lot more than just change it. Lots of things are likely damaged by a loose chain whacking around in there...

[jct842]

I don't know that he "broke" the chain, but when some one cuts or shortens a chain you normally use a chain breaker. They sell them for bicycle chains, saw chains and go cart chains and have a feature on some that can put a chain back together with the same tool. At the hardware store saw shop they take bulk chain and break it and re-rivit it back so you have an endless chain to install on your saw. I wonder why that method could not be used on a cam chain. There certainly is a lot of stress on a saw chain and I have never seen one actually break and come apart.

[Alleyoop]

Yes they do break the chain and then tack on the new one and pull it through, but then they put the new link in and tack weld the pins. That chain is moving quite fast in there and you sure don't want just a push on holder on the new link pins.
Alleyoop

[bigrustysr]

Thanks a bunch guys---it just keeps jumpimg time--tensioner is at max (new tensioner) chain still lose--Stretched chain?? =already did top end rebuild (cylinder--head with big valves--piston and rings)hope chain cures timing jumping--will see

[bigrustysr]

also checked head and cylinder to be sure they they whe same height as old one -they were identical

[jct842]

I think it to be mandatory to check height when swapping out the head. If the height be even 1/4" higher it is going to take a chain that is 1/2" more. You did good there.

[bigrustysr]

Thanks jct842 when a get a chance to tear it down i can see if timing gear on crank is ok-all ready have new timing chain just need to get busy i guess

[Bashan]

It jumps time? What exactly happens? Rich