4.0 SOHC ?'s

[dlw1146]

Are both cams the same or are they different? If different, how can one tell the difference?

When timing, is the slot in the non-gear end of the cam suppose to be above center, or below.
Watching videos on Youtube, I've seen both ways.

When # 1 piston is TDC, is #5 TDC also? If not, which piston is?
#5 is easier to get to.

Any help appreciated.
dlw

 

[boominXplorer]

The easiest way to tell difference in cams is on the passenger side cam the gear bolts on reverse thread. When setting the timing the crank is set at #1 tdc and the cam slots at the end will be parallel to the head with the big part of the circle towards the top.

If you use the otc timing kit it will set the crank right at tdc for you. If your trying to time it without it good luck!

 

[dlw1146]

Thank you for replying.

The engine is already rebuilt and installed. There is a loud 'click, tap one might say' at #3. Had to remove passenger side cam to try and find out what the problem was. I need to find TDC by getting #1 to TDC. #5 would be easier is all if it is the correct piston. When #1 is TDC, my understanding is #5 is also. I'm just trying to find out for sure.

dlw

 

[boominXplorer]

Check the top oil tube to cam lobe clearance. You'll have to spin the motor over and check for contact or if its very close. It should have at least 3/16 clearance off the lobe. You can "bend" it up for clearance.

Did it run good other than the noise? There is a tdc pointer on the crank pos sensor and a mark for tdc on balancer

 

[dlw1146]

Did not run well. Fixed exhaust lead. Seems like it is 'out of time'.
I'm trying to find out if the cams are installed with the slot toward the bottom.
Need engine at TDC to find out.

Balancer is internal.
Will check out crank pos sensor tomorrow early.

Until then,
dlw

 

[dlw1146]

In the photo, top line is at 10. Should I turn the engine around to TDC or is it OK to leave it as is. How to know if it is on intake or exhaust stroke other than pulling #1 spark plug.

 

[2000StreetRod]

The numbers are not the timing marks. The notches are the timing marks.

When cylinder 1 is at TDC on the compression stroke the camshaft position sensor "nub" on the driver side camshaft will be above the centerline of the camshaft.

The correct position of the camshafts when cylinder 1 is at TDC on the compression stroke is the timing slot is parallel to the head surface that mates with the valve cover and below the centerline of the camshaft.

 

[dlw1146]

You are an oasis in the desert. Thank you so much for your replies and your, 'My Helpful Threads.'
They are bookmarked.

The cams were upside down. Now, figuring out if it can be corrected while still installed.

 

[2000StreetRod]

The cams were upside down. Now, figuring out if it can be corrected while still installed.

The camshafts only rotate 180 degrees when the crankshaft rotates 360 degrees. If both camshafts were upside down when the crankshaft is at TDC then rotate the crankshaft 360 degrees and check the camshafts again.

 

[dlw1146]

Crankshaft is at TDC.
Both camshaft slots are on bottom and parallel to surface of heads.

When turning engine over manually, crankshaft freezes about 20 degrees before TDC.

Any ideas why?

 

[2000StreetRod]

Have the spark plugs been removed? If so, check for an extended valve that might be stuck or bent.