Cam and crank gear marks
October 4th, 2017, 01:11 PM
#1
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Join Date: Mar 2015
Location: Denmark
Posts: 241
Cam and crank gear marks
Hi everybody
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
October 4th, 2017, 09:35 PM
#2
Hi everybody
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
The book shows and says quite clearly that the Crank Gear mark is at Twelve O'clock and the Camshaft Gear is at 6 O'clock. Hope you're going down the right path.
October 5th, 2017, 01:18 PM
#5
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Join Date: Oct 2009
Location: Poteau, Ok
Posts: 40,551
This will be easier to understand:
The cam gear rotates exactly once for each two times the crank rotates, the cam gear lines up at the 12 o'clock crank and 6 o'clock cam gear orientation when the #6 cylinders on the compression stroke, rotate the engine one complete revolution and the cranks again at 12 o'clock but the cam gears index mark is now at 12 o'clock, indicating the #1 cylinders at the compression stroke, you use the 12/6 index to install cams simply because its easier to align correctly ,visually, but you need to rotate the engine to the 12/12 orientation before dropping the distributor back in, the distributor won't fully seat unless the oil pump drive shaft seats up into the distributor gear, as you remove the distributor the helical gear interface tends to turn the pump drive shaft slightly, you can use a long 1/4 drive extension and a 5/16 socket taped to it to turn that back to the correct location.
The cam gear rotates exactly once for each two times the crank rotates, the cam gear lines up at the 12 o'clock crank and 6 o'clock cam gear orientation when the #6 cylinders on the compression stroke, rotate the engine one complete revolution and the cranks again at 12 o'clock but the cam gears index mark is now at 12 o'clock, indicating the #1 cylinders at the compression stroke, you use the 12/6 index to install cams simply because its easier to align correctly ,visually, but you need to rotate the engine to the 12/12 orientation before dropping the distributor back in, the distributor won't fully seat unless the oil pump drive shaft seats up into the distributor gear, as you remove the distributor the helical gear interface tends to turn the pump drive shaft slightly, you can use a long 1/4 drive extension and a 5/16 socket taped to it to turn that back to the correct location.
October 6th, 2017, 12:56 AM
#6
Registered User
Join Date: May 2009
Location: S.E. Louisiana, so far still in U.S.A.
Posts: 1,613
Hi everybody
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
I am putting my 394 cui together with new cam and so. I am trying to understand what I might do wrong or maybe not. I fitted the new cam and cam chain set a few days ago, and dont want to fit the cover before I have my little problem solved. This is where I need you, please.
Cylinder no. 1 is at tdc and the crank gear "0" mark is at 12 o'clock, and the inlet and exhaust valve on no. 1 are closed (inlet have just closed ), so this must be compression stroke on no. 1, correct??? and the cam gear mark is at 12 o'clock too.
When I an trying to confirm this reading here and there, everybody writes about crank gear "0" should be at 12 o'clock and cam gear at 6 o'clock, and then I recall I read somewhere that Oldsmobile are different, and will have compression on cyl. 1 with BOTH gear marks at 12 o'clock.
Am I in the right track??
October 8th, 2017, 03:52 AM
#8
Registered User
Thread Starter
Join Date: Mar 2015
Location: Denmark
Posts: 241
This will be easier to understand:
The cam gear rotates exactly once for each two times the crank rotates, the cam gear lines up at the 12 o'clock crank and 6 o'clock cam gear orientation when the #6 cylinders on the compression stroke, rotate the engine one complete revolution and the cranks again at 12 o'clock but the cam gears index mark is now at 12 o'clock, indicating the #1 cylinders at the compression stroke, you use the 12/6 index to install cams simply because its easier to align correctly ,visually, but you need to rotate the engine to the 12/12 orientation before dropping the distributor back in, the distributor won't fully seat unless the oil pump drive shaft seats up into the distributor gear, as you remove the distributor the helical gear interface tends to turn the pump drive shaft slightly, you can use a long 1/4 drive extension and a 5/16 socket taped to it to turn that back to the correct location.
The cam gear rotates exactly once for each two times the crank rotates, the cam gear lines up at the 12 o'clock crank and 6 o'clock cam gear orientation when the #6 cylinders on the compression stroke, rotate the engine one complete revolution and the cranks again at 12 o'clock but the cam gears index mark is now at 12 o'clock, indicating the #1 cylinders at the compression stroke, you use the 12/6 index to install cams simply because its easier to align correctly ,visually, but you need to rotate the engine to the 12/12 orientation before dropping the distributor back in, the distributor won't fully seat unless the oil pump drive shaft seats up into the distributor gear, as you remove the distributor the helical gear interface tends to turn the pump drive shaft slightly, you can use a long 1/4 drive extension and a 5/16 socket taped to it to turn that back to the correct location.
The describsion you made above is very understandable for me, and that is exactly how I made it when I put it together and how it is now. 12/12 o'clock o the gears and compr on cyl one.
As I see it I cant even put it together the way around. Which made it even worse for me.
Thank you Eric, thanks to everybody
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