New cylinder install on an ms310

[palmer78]

I just joined this site and have some questions about installing an aftermarket cylinder on a Stihl ms310.  The bolt holes on the new cylinder are not threaded.  I thought the manufacturer forgot to tap the threads, but a local shop said I have to screw the bolts right into the unthreaded holes, basically self tapping as I go.  I am a little reluctant to do this since I have never heard of this before, so I wanted to get some opinions from guys who have done this before, and maybe some other pointers about putting this saw back together.  Thanks in advance for your help.

[T Welsh]

 palmer78, I would look at the old cylinder and see how they tapped the hole,s in it, they probably tapped them from the bottom. I do not know what type of aftermarket cyl. you bought but I would investigate this further and find out if the OEM cylinders come this way,if they do then I would say go for it and self tap the holes. One thing that would tell me to do it is are the screws themselves self tappers? If they are not I would tap the hole by hand and make sure the halves are well sealed and that the seals are in good shape! here is an IPL to help you.http://www.smaf-touseau.com/planche/?id_document=30. Hope this helps. Tim

[Slab Slicer]

Accoding to the link posted, the bolts are self tapping. Never would have tought so. I would still prefer to tap them myself. Never rebuilt a saw motor though. Alot of dirt bike and quad motors, but never a saw.

[T Welsh]

Slab Slicer, Your right! I just looked at the bolt description and they are self tapping,(Wifey called me for super) So the next step is to find the proper torque setting and follow it to a tee. If some one doesn't come up with a setting you can tap them in yourself until they seat the cylinder,then gently walk them in at a cross pattern until you feel they are good and solid. I would find out the torque setting at your local shop if I where doing it! Its critical. and if you strip the cylinder you are out the cost of it. Hopefully some one will chime in with the setting. Tim

[palmer78]

OK, thanks for the replies.  I'll try to find a torque spec.  Hopefully it goes together easier than I'm thinking.  I'm imagining trying to thread these bolts in  while making a mess with the gasket maker that seals it instead of an actual gasket. 

[JohnG28]

Maybe thread them in a little each to start them, then carefully back them out and apply the gasket material. Start them back again and torque them down to spec.

[joe_indi]

The tightening torque is 11 Nm.

The screws are self threading, so you dont need to tap them.
However, being a clam-shell,  to avoid problems of the engine pan seating properly here is what I would do.
With the engine pan in place, but without the crank shaft or such, tighten down the screws uniformly. Turn in half turn back out half turn, turn in a full turn back out half a turn,
Or: Half in-Half out-One in-Half out....... repeat this sequence till you have all the screws down to their seats.
Next, unscrew the 4 screws and this time fit the cylinder and pan in the engine housing, with those 4 metal sleeves in place.Check if there is any movement of the cylinder after you have tightened the 4 screws.
If there is any movement, you can file off a wee bit from the ends of the metal sleeves to ensure the cylinder and pan are tight.
Remember to use some thread lock when you finally do it with the crankshaft in place.

Joe