After timing belt broke - need diagnosis help

#1

So, the timing belt broke at Road Atlanta just before the enduro ended.

Today I pulled the head. Not shockingly, 5 of the 6 exhaust rockers were broken. When the head came off, you can see that the piston hit the exhaust valve on all 6 cylinders, but the piston does not appear to be cracked or even badly mangled. Where the relief is in the piston, there is a little sharpeness from the metal from where the contact was. Is this something I can take some gritty sandpaper and just sand down to get the sharpness off and be good with? I took some pictures but do not have the cable here to take them off the camera. Thoughts?

#2

It’ll be fine to just de-bur the pistons and pop a new head on, I would junk the old head not repair it. 5 out of 6 exhaust valves would make me think the head could be cracked around the rocker shaft.

How old was the timing belt??

Greg

#3

I’m not repairing the head, I’m going to buy Ranger’s rebuilt head. I have no idea how old the timing belt was, I didn’t change it. Shame on me. Is there any particular brand I should buy, and do I need to change the tensioner?

#4

Buy the Continental kit and it comes with a tensioner.

#5

The preferred brand of belt is a Continental/ Conti tech and yes replace the tensioner!! Almost all parts vendors sell it as a kit and it comes with the tensioner. If the tensioner pin & spring are missing make sure you order those as well. Lots of times a previous owner of crappy shop will to a dirty water pump replacement and leave those parts out. So make sure you change the water pump while your in there also. The list of while your in there can be endless while doing this job!!

I’m actually pulling mine apart tomorrow to replace a 4 year old timing belt.

#6

I found out at Road Atlanta that the water pump is best done during timing belt swap.

#7

My water pump is new so that will be OK. And I misspoke, it broke one exhaust rocker and 4 intake rockers. The intake side of the pistons look fine.

Now I guess I get to set lash…is that done just spinning the engine over by hand or does it have to be running? My old dirt bike had to be running, and that was a mess to do.

#8

Turn it by hand. It’s a pretty simple job that takes a wrench for the crank bolt (22mm), a 10mm box end wrench, feeler gauges (angled are nice), and something to stick in the eccentric hole. There is a factory tool, I’ve always used a small allen key. Engine should be stone cold.

#9

BigKeyserSoze wrote:

[quote]I’m not repairing the head, I’m going to buy Ranger’s rebuilt head. [/quote]This is news to Ranger, who’s out of town until 31Jul.

#10

oops. I sent you an e-mail and PM, assumed you got it. I guess maybe not? Let me know if the head is still available.