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I'm having trouble timing my 451 engine. I have the AllData, Mitchell and Mercedes instructions so it should be easy, but it isn't. Here are the problems I'm having.

1) First there are several marks on the cams and crank. There is a quarter inch long line on the gear and a dot on the exhaust cam gear tooth. There is a notch and a dot on the exhaust cam gear tooth. And last, there are three marks on the crank, a notch, a dot on the timing chain gear and a third dot between the gear and the crank.

2) If I time it the way AllData describe, with the crank notch at the triangle pointer in the crankcase, and the intake cam notch inline with the quarter-inch line on the exhaust cam, I get interference. I have gotten interference a number of ways, using different marks, but I can't remember them all.

3) The Mercedes manual says, as I understand it, to line the triangle pointer on the harmonic balancer with the 10 degree BTDC mark on the timing cover. Mercedes then says the line on the exhaust cam should line up with the notch on the intake cam. I'm inclined to believe Mercedes, but the problem is at that mark the no 1 cylinder is not near TDC, nor are any of the other cylinders. Top TDC for the number one cylinder, the one closest to the crank end, is when the marker is approximately 90 degrees past the BTDC indicator on the timing cover, where there are no marks at all on the balancer.

4) Last, there is a note in the Mitchell data, from a third-party tech, that says the book is wrong and the timing should be set so that the dot on the crank between the gear teeth and the shaft lines with the triangle marker on the crankcase and the line on the exhaust cam gear should line up with the dot on the exhaust cam gear tooth. The engine spins when I do this and I get compression, but I have no idea if this is actually correct.

Please help, Has anyone out there successfully timed this engine?
 

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valve timing

For what it's worth, here is some information on valve timing from my own personal experience. When I pulled my blown 08 smart engine, I made some notes regarding the relation of the various parts to each other. The following is what I observed before removing the timing chain. With the #1 piston at TDC and the small v-nick on the harmonic balancer set at the center (TDC) of the three marks on the timing scale and chain tensioned as in operating condition, the small dot on the left (exhaust) cam sprocket was slightly left (counterclockise )of 12 oclock position and the dot on the right (intake) sprocket was slightly to the right (clockwise) of 12 oclock. With an outside link plate of the timing chain centered over the both sprocket marks and no slack in the chain , there should be ten outside chain plates from sprocket to sprocket, number one centered over the left sprocket dot and number ten over the right sprocket dot. The long 1/4 in. mark on the exhaust sprocket will be directly in line (horizontally) with a small notch on the intake valve timing drum , and center TDC mark aligned with the little v notch on the crank It's been several years since I did this and I have to rely more on my notes than my memory, but this should be correct.
 
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