Hello List,

This a repost of my dilema in replacing the head and timing it correctly.

Any input would be welcome.

thanks

Gavinbr


Join Date: Nov 2004
Posts: 93

m103~300e 1991 expert help needed

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Hello.

Have just replaced my head gasket on the above engine.

However, I now have the valves hitting the pistons, no damage!

Have followed the instructions for mecanical timing, that is TDC on the harmonic balancer, and the dot on the cam shaft in line with the marker, and both valves on#1 closed. The cam sprocket in the pin hole for that purpose.

Question for the experts, it appears that when the piston on #1 is on top dead center [ noted visually] the harmonic balancer shows it in line with the magnet for the ignition timing? Suggesting that is TDC and not O/T?

Question, what should you use as the TDC mark on the harmonic balancer?
Tha manual say's use O/T, reference Engine job 05-2230 mech., timing

Thanks

Brian


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#2 06-13-2008, 07:16 AM
M.B.DOC
Moderator Join Date: Mar 1999
Location: Tucker, Ga USA
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When the balancer is at the O/T mark the #1 piston also has to be at the top.

The magnet ONLY serves as a reference for dynamic timing with a scope.

The timing mark on the camshaft must align with the mark on the cam bearing when the piston is a TDC.
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#3 06-13-2008, 08:37 AM
t walgamuth
dieselarchitect Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 14,724

I hope you haven't bent any of the valves.

Tom W
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#4 06-13-2008, 02:34 PM
gavinbr
Registered User Join Date: Nov 2004
Posts: 93

m103~300e 1991 expert help needed mech timing

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Guys,

Thanks for your response.

Didn't damage the valves turning by hand.

Here's the weird part, with the head off and observing the piston on #1 and the timing balancer position at O/T mark it does not put the piston at TDC, rather a bit lower.

However if we move it to where the magnet is located, the piston is now exactly flush with the top of the block?

There's something I'm are not getting, the manual is very clear on the positioning for mechanical timing?

At the O/T position it taps the pistons? At the magnet position its clear of the pistons.

Whats going on.

The 103 engine is typically not difficult to time, assuming that your front crank damper is on correctly. Start by visually inspecting the 6 bolts that connect it to the crankshaft hub. I'm 99% sure that the bolts are offset and all 6 won't fit if it is installed in the wrong position. If all 6 bolts are in then it is most likely that the damper isn't the problem.

Next verify that you are using the right part of the pointer to set the engine at TDC. The bracket on the timing cover has a small tab pointing to the exhaust side of the engine that terminates in a short 90 degree bend. This small bent portion of the tab is what should line up at 0T with the engine at TDC.

With the engine confirmed to be at TDC you want to confirm that the camshaft is at the TDC position. If your marks are lined up correctly the cam lobes on the #6 cylinder should be pointing up so that they form a "V" with the followers both inside this "V" but not lifing either valve. The #1 cylinder cam lobes should be opposite of #6 and pointing equidistant downward.

With the engine at TDC and the cam aligned as described you should be able to make 2 revolutions of the crank with no interference.