Turn the engine by hand

[earlybird]

Can you put a socket spanner on the crankshaft pulley retaining nut?

 

[Roberto]

How does one "turn the engine by hand", a 4cyl 4108 ? Is there a more precise way to rotate it little by little rather than short bursts of the starter motor ?




thanks

 

[JayBee]

If you are able to decompress the cylinders, you should be able to rotate the engine by pulling the alternator belt, or by putting a spanner on the pulley retaining nut.

 

[Cliveshep]

Ah, a man who is setting valve clearances!

Spanner on crank nut is the way.

For valves use rule of 9

If no. 1 valve is down - adjust 9
if no 2 valve is down - adjust 8

and so on.

If exhaust and inlet valves are different gaps, look carefully at inlet manifold to identify which is which.

 

[Roberto]

thanks for your comments


I have this second pulley fitted (for the 2nd alternator) which hides the bolt, not sure I could fit a socket there.. (Is this the crankshaft bolt ?)


Maybe take some giant crocodile pliers and try and grab the pulley itself ?

The engine has no decompressor, if I take the injectors out then would it be possible to turn it by the alternator pulley ?




Cliveshep,
the 9 rule sounds very nice, though I have some difficulties in understanding the meaning: when you say "If no. 1 valve is down - adjust 9", what does it mean, what is number 9 ? :shy:

thanks
:smile:

 

[lenseman]

. . . I have this second pulley fitted (for the 2nd alternator) which hides the bolt, not sure I could fit a socket there.. (Is this the crankshaft bolt ?)


Maybe take some giant crocodile pliers and try and grab the pulley itself ? No! you might damage or break the pulley or mark it such that it will effect the longevity of the Alternator belt.

The engine has no decompressor, if I take the injectors out then would it be possible to turn it by the alternator pulley ? . . . .

Try not to remove the injectors as they have to seat correctly and TIGHT on return and dirt and grit can get into the cylinders whilst they are removed.

In your photograph, the BIG BOLT 'inside' the lower black pulley is the one to get a socket to fit. It is probably between 28mm and 32mm and you might need a 10cm extension to allow you to get a 30mm 'T'-bar on the be able to rotate this crankshaft bolt. Do not even think about using a 13mm ring spanner on those three small bolts which hold the lower pulley onto a boss! They will snap off!!

 

[vyv_cox]

My understanding of the '9 rule' is that the total is always 9. So with 1 down adjust 8, with 5 down adjust 4, and so on.

Taking out the injectors to turn the engine over is a very drastic move. Looks much easier to take the secondary pulley off by removing the three small bolts, then put a big socket on the crankshaft bolt. I would be very surprised if you could turn the engine over using grips or pliers.

 

[Roberto]

I agree absolutely about injectors, it would be a hell of a job to do just to check valve clearances, maybe the easiest is indeed to remove the big black pulley and try with a socket on the bolt

My understanding of the '9 rule' is that the total is always 9. So with 1 down adjust 8, with 5 down adjust 4, and so on.
.

that's what I thought too, but do those numbers identify the eight valves ?
If so, is there a default numbering system ? for example are valves 1 and 2 the intake and exhaust valves of first cylinder, valves 3 and 4 respectively intake and exhaust of cylindre number 2 .... ?

or valves number 1 2 3 4 are intake and valves 5 6 7 8 are exhaust ?

sorry if it is obvious... :shy:

 

[vyv_cox]

I agree absolutely about injectors, it would be a hell of a job to do just to check valve clearances, maybe the easiest is indeed to remove the big black pulley and try with a socket on the bolt





that's what I thought too, but do those numbers identify the eight valves ?
If so, is there a default numbering system ? for example are valves 1 and 2 the intake and exhaust valves of first cylinder, valves 3 and 4 respectively intake and exhaust of cylindre number 2 .... ?

or valves number 1 2 3 4 are intake and valves 5 6 7 8 are exhaust ?

sorry if it is obvious... :shy:

The convention as I know it is that numbering starts from the water pump end, for automotive applications, and goes sequentially. So exhaust, inlet, exhaust, inlet and so on.

 

[TQA]

If you can, use a socket on the crankshaft pulley retaining nut and only turn in the direction of tightening the nut. It should be an imperial nut about 1 and 1/4 across flats NOT metric. [ It is an OLD Perkins ]

Do not remove the injectors.

An alternative method is to remove the starter motor and use a lever or large screwdriver on the ring gear to turn the engine. Takes a while but gets the job done.

On most older 4 cyl engines with siamesed inlet ports valves 1,4,5,8 are exhaust 3,4,6,7 inlet. I am about 96% sure the Perkins 4.108 folows that plan.

I am also remembering that you should have a new rocker cover gasket to hand. I think they are cork and are likely to leak if reused.

 

[lenseman]

If you can, use a socket on the crankshaft pulley retaining nut and only turn in the direction of tightening the nut. It should be an imperial nut about 1¼ inch across flats NOT metric. [ It is an OLD Perkins ] . . .

I only mentioned the size in metric as Roberto lives in France. The nearest size to 1¼" would be 32mm which would suit admirably.

 

[omega2]

Ah, a man who is setting valve clearances!

Spanner on crank nut is the way.

For valves use rule of 9

If no. 1 valve is down - adjust 9
if no 2 valve is down - adjust 8

and so on.

If exhaust and inlet valves are different gaps, look carefully at inlet manifold to identify which is which.

RULE OF NINE IS= 1do8=9
2do7=9
3do6=9
and so on. the total of the open valve and the one to adjust = NINE

 

[Roberto]

thanks

thank you all!

 

[david_bagshaw]

Can you put a socket spanner on the crankshaft pulley retaining nut?

Note the direction of running, either use a strap wrench, or you could use a spanner on the extra alternator,& turn slowly, pushing a thumb on the slack side of the belt to maintain drive, & allow the compression to leak away. (use to do this with a M Benz OM 314 4 cyl 80hp with a pulley for a pump on the front which covered the crank nut) If that bothers you I would make a plywood shape to fit inside the crank pully and bolt a square onto the wood, & put spanner there.

suprisingly little force is required to turn a healthy engine, so long as you do it slowly.

 

[Poignard]

How does one "turn the engine by hand", a 4cyl 4108 ? Is there a more precise way to rotate it little by little rather than short bursts of the starter motor ?




thanks

There is a special tool for turning engines which engages with the teeth on the flywheel

http://www.jegs.com/webapp/wcs/stor...01&partNumber=555-80530&langId=-1&showValue=1

I happen have one similar to this, new and unused, (but a different make) that I want to sell