You are here

Cam Alignment

Seeking thoughts and opportunities to sound out with all, what the issue could be. Putting together another 179, does have new cam, timing gear, powerbond balancer.

Coming to adjust the rockers, at TDC cylinder 1, expect to see valves 7&9 fully open. They are not, and do not open until the timing mark has rotated 180 degrees.

At TDC Valves 1&2 are both closed as they should be

I could understand if the timing gear marks were not aligned correctly, but I am 100% certain that they are.

Welcome thoughts and experience, comments

Thanks
Tom

Model: 
Topic: 
Engine: 
Section: 

Comments

Double check that the camshaft gear and the crankshaft gear marks are alligned, bearing in mind that they will only actually line up each time after two full rotations of the crankshaft.

The timing gear for the camshaft should be numbered 44AL.
The timing gear for the crankshaft should be marked 44B.

If all is ok there, then you might just have to remove and rotate the cam gear 180 degrees and slide it back in.

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

"If all is ok there, then you might just have to remove and rotate the cam gear 180 degrees and slide it back in."
----------------
Would be a LOT easier to just rotate the entire engine one complete turn. Crank is back in same position and cam has moved 180 deg :-)

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

______________________________________________
[http://gallery.oldho...|me shed...]

At top dead centre valves 1 & 2 will be shut. While 11 & 12 will be "on the rock" as in one almost closed and the other just opening. Also...when setting valves just watch the opposite cylinder. So.....with valves for number 6 on the rock, set number 1. To set cylinder 2 watch number 5. For 3 watch 4.....and so on

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

Q-ball.

"Clay is for racing on,Tar is how you get there!!"
[http://gallery.oldho...|My Shed]
3401

Firing order 153624.

When Cyl 1 is at TDC on the firing stroke (both valves closed) ...

Cyl 4 (valve 7 Intake & valve 8 Exhaust), has just fired
Cyl 5 (valve 9 Exhaust & valve 10 Intake) is next.

Cyl 4 is on the power stroke. The crank angle is 120 deg ATDC. Both valves appear closed. The exhaust valve (8) will be in the process of opening.

Cyl 5 is on the compression stroke. The crank angle is 120 deg BTDC) so both its valves appear closed. The intake valve (10) will be in the process of closing.

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

T

My Shed

Holdenpaedia, they're the brakes Mate.

I think what tomjamo means is that when the 2 timing cogs are lined up dot to dot, it's not on no. 1 TDC firing, & its valves are not closed.

In my experience most motors for whatever reason, line up their timing marks on no. 1 TDC exhaust, which is actually no. 6 TDC firing. Go figure.

It doesn't matter really, if you rotate the motor 1 full revolution, it will go to no. 1 TDC firing, & then two no.1 valves will be fully closed. It's then the marks do not line up. So what !!

Dr Terry

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

My point was that changing the phasing between the cam and the crank by pulling the cam out and turning it half a turn and putting it back in would have the same effect as holding the cam still and rotating the crank a full turn. Nett result = zero.
-----
As for dots vs valve position, if the dots meet at number 1 TDC exhaust then the inlet would also be open. This overlap is a relatively narrow area of the cam. If you can only see the rocker arms, or the tops of the lifters with the side plate off and not the actual cam itself then at least you have narrowed the cam position down to a small area.

If the dots met with number 1 at top of compression stroke with both valves closed then the cam can rotate quite a way with no movement of the number 1 rockers and you don't know exactly where it is if you can't see the actual cam.

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

______________________________________________
[http://gallery.oldho...|me shed...]

you havent got a 12 port cam have you

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

What drugs you on tell us what a 12 port cam is?

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.

Whats wrong with Melbourne drug addicts sleeping all over the footpath trying to scab money?

  • Like0
  • no like0
  • Holdenpaedia idea0
  • Funny0
  • Wrong Category0
Please use, Holdenpaedia will get the first box on the left side. Post any suggestions.