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-   -   How to trun engine for valve adjustment (http://forums.pelicanparts.com/porsche-911-technical-forum/318334-how-trun-engine-valve-adjustment.html)

npresley 12-03-2006 02:08 PM

How to trun engine for valve adjustment
 
My question is how do I turn the engine over? My fan belt slips on the fan pulley, thus not allowing me to turn the engine crank. Should the belt be replaced and tightened to be able to turn the crankshaft?
Thanks in advance,
Nathan

GrantG 12-03-2006 02:12 PM

Yes, either tighten the belt (remove shim(s)) and try again or you can turn it from the nut on the crank pulley (below the fan pulley)

sand_man 12-03-2006 02:46 PM

Try squeezing the belt around the pulley with one hand, while turning the fan bolt with the other. This should take up enough slack to make the belt grab and turn the crank pulley. Watch your fingers! Obviously make sure the tranny is in neutral.

dentist90 12-03-2006 03:44 PM

If you have removed all the shims and the belt still slips it is time for a new belt anyway. You'll lose cooling and charging (alternator) efficiency if it's too loose.

I'm also told to only turn the crank in it's normal rotation, never opposite as it can damage the timing chain tensioners? Can anyone explain why this is so?

MAS956 12-03-2006 03:51 PM

Also, if you haven't yet moved the plugs, do so now. That will allow the engine to turn much more freely.

sand_man 12-03-2006 03:51 PM

The tension on my belt is perfect and whenever I do a valve adjustment, it (the belt) usually will slip around the crank pulley during a compression stroke as I turn the nut on the fan pulley...unless of course I apply some tension to the belt with my free hand - then it (the engine) turns just fine.

sand_man 12-03-2006 03:53 PM

I think it's a bad idea to remove the plugs for a valve adjustment. It's not necessary to help the engine turn and removal can actually disloge carbon which could throw off your adjustment.

Zef 12-03-2006 04:23 PM

+ 1 on the Sand_Man advice...turn the fan pulley nut with some tension on the belt and it will turn the engine as well.

john walker's workshop 12-03-2006 07:28 PM

turn wih a ratchet in the left hand and push in on the right side of the belt with your right. and leave the plugs in.

KFC911 12-04-2006 05:46 AM

Quote:

Originally posted by john walker's workshop
turn wih a ratchet in the left hand and push in on the right side of the belt with your right. and leave the plugs in.
I hold the ratchet in my right hand pushing down, and reach across underneath with my left hand to apply tension to the right side of the belt. This is the ONLY time that I will disagree with John Walker, but I'm left-handed, and that works better for me :)

npresley 12-04-2006 06:25 AM

Thanks everyone; I appreciate it. I don't know why I don't think of this stuff. I guess it has something to do with being in the moment when it is cold in the garage.

T77911S 12-04-2006 08:47 AM

i just timed mine. pull all the plugs and squeze the belt.

Nitrometano 12-04-2006 09:00 PM

damn!!! I hate that. My next modification would be to drill an hole into the engine mount brace, in the area of the underdrive pulley to place an 19mm long socket to turn the engine when I need it.

911pcars 12-04-2006 10:31 PM

Attach remote starter switch to solenoid. Bump engine to correct adjustment position. Avoid moving one inch from your laid out position until 3 valves are adjusted, then roll over 360º to repeat on the other bank.

Sherwood

sand_man 12-05-2006 04:55 AM

I always do my valves one side at a time, too. I jack up one side of the car to let any excess oil in the lower cover run back into the case and then I just turn the engine 240 degrees each time I need to move to a different cylinder on the same side (instead of the 120 called for to move from bank to bank). When one side is done, I repeat the process by jacking up the other side.

I have NEVER had an issue turning over my engine by applying pressure to one side of the V-belt and then turning the fan nut. Never had to remove the spark plugs. Granted my engine's CR is 7.3:1.

David 12-05-2006 05:56 AM

Quote:

Originally posted by Nitrometano
damn!!! I hate that. My next modification would be to drill an hole into the engine mount brace, in the area of the underdrive pulley to place an 19mm long socket to turn the engine when I need it.
That's what I did when I rebuilt my engine. I just got finished with my post break in valve adjustment and it was a piece of cake.

Ken911 12-05-2006 04:47 PM

I do the squeeze the belt thing on my carrera it's 10.3 to 1 row motor works just fine

1982911SCTarga 12-05-2006 05:00 PM

+1

My SC is 9.3:1 and it easily rolls over by squeezing the belt. There's no magic or mystery to it. One other thing, only turn your engine over big amounts by going clockwise.

Brian


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