FINDInG TDC IN an M42

[fiftytakedowns]

Hey,

I have a JB racing flywheel so I dont have the TDC pin to hold it in place. how can I double check that the cams are EXACTLY in line with TDC of engine? I just used a probe to measure the top of the combustion stroke and set it to that.

Is there a certain notch on the pulley or soemthign, because there is no mark on the front timing case.

I am not 100% sure I got the EXACT location of the piston correctly, as you can find teh top of the stroke for the piston,bt you can move the wrench on the crank bolt a little bit before it starts moving back down (thats what the cyl probe shows at least. the reason I am concerned is because of the misfiring issue I am having from 2k-3k rpm that happens sort of randomly or sometimes when up or downshifting into that RPM range. I am trying to rule out cam synchronizing with the cam position sensor as a possibility.

[Dj Buttchug]

dont forget theres an arrow on the oil filter housing that shows the exact point of TDC. Line the arrow up with the notch on the crank pully.

As for the cams. You can double check by both arrows pointing straight up on the cam gears.

Also triple check your cam position buy looking at the lobes on cyl #1. The lobes should be pointing in a 45 degree angle towards each other. ill see if i can find you a pic

[Dj Buttchug]

stand by while i create a cam lobe pic

[Dj Buttchug]

This engine is not on TDC but its the best pic i could find. I wish i had a better one

[fiftytakedowns]

Does that little arrow point towards the missing tooth on the crank pulley?

[Dj Buttchug]

yes. match the arrow up with the notch in the pulley and your crank is set

[fiftytakedowns]

Legit I'll have to check that out

[Dj Buttchug]

if you have the crank set and the cam gear arrows pointing upwards its hard to have the timing off.

You can also check the back of the cams. they are square and they must line up horizontally with the head.

The only way you could really make a mistake is if you remove the cam gears from the actual cams. Then you couldnt rely on the cam gear arrows or the square cam ends for reassurance.

[fiftytakedowns]

I think I got it really close cause the car runs smoothly, but like I said I wanna make sure the cam sensor isn't causing a misfire due to poor placement.

[KenC]

If it's off a tiny bit, it won't cause a misfire. The cams are adjustable 6deg forward and backward.

[fiftytakedowns]

If it's off a tiny bit, it won't cause a misfire. The cams are adjustable 6deg forward and backward.

Good to know, I'll mark it off the list. Of possibilities.

[rjcaptsean]

Ok.. I might have screwed up big time. Geez.. it wouldn't be the first time today of course.

I did not have the Oil filter housing mounted but I used the "screwdriver in the hole" method of finding top dead center for Number 1 cyl. This ended up with the woodruff key on the crank being relatively at the 12 o'clock position. I see on the above pic that the small pin on the crankshaft pulley being at 3 o'clock and mine is at the 9 o'clock position. Could I have it 180 degs off? (The black square is the woodruff key)


As for the "missing tooth" on the crank gear... I don't see one.

[Dj Buttchug]

^ nope your good.

[vpilarrt]

The "missing tooth" is on the harmonic balancer and is the tooth for the crank position sensor - its more of a bump than a tooth.

[fiftytakedowns]

Still confused.. the arrow points to the missing tooth? or a notch in the crank pulley?