Timing Mark is Off- See Pic
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
Timing Mark is Off- See Pic
I am putting this engine together and have installed the new Pioneer harmonic balancer. I don't understand why the line on the harmonic balancer is not lined up with the timing marks on the timing chain cover. My #1 piston is all the way up- see pic. --newbie here though. 
http://www.photohost.org/gallery/sho...cat/500/page/1
http://www.photohost.org/gallery/sho...cat/500/page/1
Racer
Joined: May 2004
Posts: 301
Likes: 2
From: Boca Raton Fl
Have you confirmed the TDC #1 is correct by using the manual method?
Put a feeler in #1 plug hole
Turn clockwise and mark when it hits (gently)
Turn counter clockwise and mark when it hits (gently)
Split the difference should be TDC
Put a feeler in #1 plug hole
Turn clockwise and mark when it hits (gently)
Turn counter clockwise and mark when it hits (gently)
Split the difference should be TDC
Racer
Joined: Jan 2004
Posts: 377
Likes: 1
From: Anchorage Alaska
Originally Posted by 79vetter
My #1 piston is all the way up- see pic. --newbie here though.
http://www.photohost.org/gallery/sho...cat/500/page/1
http://www.photohost.org/gallery/sho...cat/500/page/1
Also, to those trying to help, notice the heads are off.
Last edited by 73 Vet; Sep 16, 2005 at 09:04 PM.
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
Originally Posted by 79vetter
Dumb question: What is a feeler?
Where on the balancer do you mark these 2 positions?
thanks
Where on the balancer do you mark these 2 positions?
thanks
As you slowly rotate crank by hand clockwise you are feeling for the piston as it rises in the cylinder. (Number One Cylinder) When it no longer moves up STOP and put a pencil mark on the balancer in line with, ah say the timing tab. Next slowly rotate crank in opposite direction until you feel the piston start to move. STOP and put another pencil mark on the balancer. Half way between these marks is TDC.
Obviously this is much easier with the head off and you can just watch the piston. You can also watch the valve action and tell which is the firing stroke and check distributer too.
I once made a sparkplug hole/dial indicator adapter to use as a probe when I messed with motorcycles. Made magneto/point setting a snap.
Good luck
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
Just feel of the #1 piston as she comes up while rotating crank clockwise (same direction engine runs) . When she stops moving up put a mark on the harmonic balancer using the timing tab as a pencil guide.
Slowly rotate backwards and when piston just moves put another mark on balancer using the same tab as a guide. TDC is halfway between these two marks..... the piston needs to be on the firing stroke when doing this, not the exhaust stroke, if you are checking dist. too.
If the factory mark on balancer is somewhere other than zero degrees it should be indicated so in some way... I think....check with your supplier.
Also, do you know for sure you put timing chain on in correct relation to crank and cam? If not now is a good time to correct it.
Slowly rotate backwards and when piston just moves put another mark on balancer using the same tab as a guide. TDC is halfway between these two marks..... the piston needs to be on the firing stroke when doing this, not the exhaust stroke, if you are checking dist. too.
If the factory mark on balancer is somewhere other than zero degrees it should be indicated so in some way... I think....check with your supplier.
Also, do you know for sure you put timing chain on in correct relation to crank and cam? If not now is a good time to correct it.
Last edited by David Ey; Sep 16, 2005 at 10:29 PM.
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Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Originally Posted by 79vetter
My heads are off so would this same theory apply?
Do you mark the 2 places on both ends on the gauge on the balancer so that directly between the 2 is the 0 degree mark?
Do you mark the 2 places on both ends on the gauge on the balancer so that directly between the 2 is the 0 degree mark?
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
I think that the stock timing tabs on the late 70's engines were different.
I see that yours is welded onto the timing chain cover.
My crate motor came with two "bolt on" tabs for the different diameter dampers.
Do you still have your old damper for a comparison?
And yes TDC is TDC.
I see that yours is welded onto the timing chain cover.
My crate motor came with two "bolt on" tabs for the different diameter dampers.
Do you still have your old damper for a comparison?
And yes TDC is TDC.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
wrong damper
It is quite likely your new damper is made for an 86-91 sbc ... their TDC mark is about 40° to left of keyway centerline ... their timing tab(actually sight-tube-affair) is also about 40° to left ... right about where your TDC mark is in your pic.
69-85 dampers' TDC mark is 10° to left of keyway centerline.
Pre-69 dampers' TDC mark is 2° to left of keyway centerline.
Again, I'd say you got a damper for a late model (86-91).
69-85 dampers' TDC mark is 10° to left of keyway centerline.
Pre-69 dampers' TDC mark is 2° to left of keyway centerline.
Again, I'd say you got a damper for a late model (86-91).
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
Did I do this right?
I did what was suggested above by marking 2 places on the balancer using the same point of reference on the side (end) of the timing tab. I placed a line exactly halfway between these 2 marks- which should be TDC. Then I moved the new line in between the other 2 to the same point of reference on the side of the timing tab. Since the factory line on my balancer is not at the 0 degree point I marked another line at the 0 degree mark on the balancer. Is this my correct TDC now? 