Camshaft

[Cees de Bunje]

Hi Guys, i finally got my engine back from the machineshop. Everything replaced. cost me a lot. however, i have noticed that they have turned the camshaft a 180 degrees. would that damage pistons and/or valves. i noticed a difference between the old and the new camshaft. the cam for the fuel pump is on different place. on the new it is opposite to the old one. i think that shouldnt matter because it drives the fuel pump and it only has to pump and it doesnt matter at what moment. am i correct ?? please let me know so i can tackle it with the machineshop. cees.

[David Thomas]

Look at your harmonic balancer keyway, compare the crank key position and verify the crank and #1 piston are in TDC position on the compression stroke. The cam sprocket and crank sprocket dots should be aligned. Look at the cam lobes for #1 cylinder, the high part of both lobes should be away from the lifter. Rotate the crank clockwise, this will pull the piston down as in the power stroke. After the piston hits BDC it will start up on the exhaust stroke, the exhaust cam lobe will start moving into position to push the lifter up to open the exhaust valve. After going through TDC continue rotating the crank and the intake stroke starts, the piston will move down, the exhaust lobe will move away from the lifter and the intake lobe will start pushing the lifter up to open the intake valve. After the piston hits BDC and starts moving up, the intake lobe will move away from the lifter to close the intake valve and you start the compression stroke, both valves should be closed with the lobes away from the lifters. When #1 hits TDC the cam sprocket and crank sprocket marks should be aligned, the #1 cylinder is in compression ready for spark, and both cam lobes are away from the lifters.

HTH, David

[Jason Edge]

If dots align you are fine. Both camshaft gear and crank gear are slotted and there is only one way they will install. If the alignment marks are next to each other you are done.  Compression stroke will come into play when you install distributor and set up ignition...that's when the real fun sometimes starts.

[Cees de Bunje]

Had a talk with the machineshop and they said they had put the #1 piston in compression position. I turned the crankshaft a full turn and now the dots align. But how can i be sure that the camshaft and the pistons are in the right position ??

[Jason Edge]

Pop the cam gear and chain off, install gear without chain, rotate the cam around until timing marks align , and reinstall gear and chain. It's a 5 minute fix.

[Cees de Bunje]

You are both right. that is why i noticed the 180 degrees difference. What my biggest concern is.......what will it do with pistons and valves. I think ignition timing will also be wrong if you try to align it with TDC #1 piston.

[Jason Edge]

It looks like from picture your timing marks ( dots that Russ is referring to) are out of sync. I see both cam gear and crank gears dots at very top of each gear. The top cam gear alignment mark should be facing straight down toward the crank gear alignment mark.