Author Topic: Timing chain question ???  (Read 544 times)

Offline JAG56Cad

Timing chain question ???
« on: August 10, 2019, 10:58:08 AM »
So I had to replace my timing chain it was a bit stretched, hand cranking the engine the distributor did not moved until I rotated the crank about .    :(

Left the engine at #1 TDC and timing mark at the harmonic balance at A. Got a new chain and a spare crank and cam sprockets.
Aligned the crank sprocket per the manual with the woodruff key as shown, timing mark pointing up.
Aligned the cam sprocket with the guide pin toward the left (same as show on the Service Manual) and timing mark aligned with the crank.
Timing for #1 remained at TDC and mark with A, #1 valves were closed (as far as Im able to see with the inspection camera).

Question is;

The manual is not detailed if the #1 would need to be at TDC with the mark at A it just indicates to align both cam and crank marks.   ::)
Only reference I was able to get was from the 1956 National Service Data which shows setting the engine to firing position on #6.
Well I did check # 6 and it also shows to be at TDC which both valves closed.  ???

Before I bottom up the cover and everything else just want to validate with other folks if the way I place my timing chain is correct. Hate to take it all apart to make correction.  :P
Jose Gomez
CLC Member #23082

Offline Lexi

Re: Timing chain question ???
« Reply #1 on: August 10, 2019, 03:59:20 PM »
Jose I have both the Chilton as well as the Motors manuals for 1956 and can dig them out and look in there for you, (unless you checked those as well). I will have a look for these for you. Clay/Lexi

Offline Lexi

Re: Timing chain question ???
« Reply #2 on: August 10, 2019, 04:18:39 PM »
Jose I dug those period manuals out and scanned the pages for you. The Chiltons has more info and is spread over 2 pages, (see 2 scans). Motors manual scan fit on one page, (see scan). Tough size of book to scan on my equipment, (one image a little cut off at right margin), can take a photo if you prefer. Hope there is something here that clarifies matters for you. Clay
« Last Edit: August 10, 2019, 04:23:46 PM by Lexi »

Offline JAG56Cad

Re: Timing chain question ???
« Reply #3 on: August 12, 2019, 08:20:34 AM »

Thanks for the info, I had no time yesterday to re-check since I got held up working on my daughters Nissan A/C clutch replacement.   >:(

The strange thing is setting both cam and crank sprockets to the same position as shown on the manual both #1 and #6 pistons are at the top with the timing mark at A.   ???

I need to re-check my settings again not sure if Im set correctly now or not. When I removed the old timing chain/sprockets I had the timing set to #1 TDC and mark at A and distributor at #1.

So now Im a bit confuse if the picture on the manual is just for illustration or if it is the actual setting with #6 at top and distributor pointing at #6.   :o

Jose Gomez
CLC Member #23082

Offline South_paw

Re: Timing chain question ???
« Reply #4 on: August 12, 2019, 08:04:18 PM »

Take the driver side valve cover off and watch the movement of the valves on #1 as you spin the crank by hand. You'll know when the compression stroke is reaching TDC because it will be right after the intake valve closes.

1956 Eldorado Biarritz
CLC Member since 2001 (Unlisted in Directory)

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Offline PHIL WHYTE CLC 14192

Re: Timing chain question ???
« Reply #5 on: August 13, 2019, 01:31:40 AM »
All I know Jose is when I put the distributor in my newly rebuilt engine I managed to put it in 180 degrees out. Believe it or not it ran! As for the timing chain I just lined up the Mark's on the sprockets as shown in the manual. However look at the problems Lou had with the new camshaft on his car, you're right to double check it all.

Offline JAG56Cad

Re: Timing chain question ???
« Reply #6 on: August 18, 2019, 08:30:53 AM »
Sorry folks did not forget about this threat, just got busy with other things.

Had a chance yesterday to do some more testing and found some interesting stuff.

Now for general info my camshaft is the original so mounting the cam sprocket as shown on the manual(s) with the mark at the bottom both #1 and #6 valves are closed.

Placing the crank sprocket as shown with the mark up both #1 and #6 piston are at the top, compression is good and holds at around 65psi and timing mark at A on the balancer.

Moving the crank a full rotation 360 places the #1 and #6 back to top. Moving the camshaft to a full 360 again places both #1 and #6 valves to full close. Both timing marks all lined up

Moving the distributor to #6 manually when all the marks are set per the manual, moving the crank until the distributor points to #1 the marks are now; crank on the bottom and cam is on the top.

So this would be at 180 rotation on both sprockets, so both #1 and #6 pistons are now all the way down with the balancer A mark on the opposite end.   ???

Rotating the crank another 180 places everything back mark on both sprockets lined up and #6 on the distributor and A on the balancer.

So Im clear that both marks on the sprockets would need to lined up, Im also clear that the picture on the Service Manual and other repair manuals the balancer would be at the correct position A since the woodruff key guide placement with this lineup for the balancer.   ;)

What is not clear on my mind is why they are describing the #6 would be at the firing position with this line up contradicting with the timing setup for #1 to be at TDC with timing mark at A.   :o

@ Lou my inspection camera allows me to see inside the cylinder and when both valves are fully closed during the piston movement. Great tool..!   ;)

@ Phill Ill place everything back as per the manual and place the distributor at #1 if my alignment is 180 off it should easy to move the distributor 180.   ;)

Thanks everyone

Jose Gomez
CLC Member #23082

Offline JAG56Cad

Re: Timing chain question ???
« Reply #7 on: September 15, 2019, 04:21:52 PM »
Folks all back together note place on the Service Manual page for anyone reference, enjoy it.
« Last Edit: September 16, 2019, 06:54:16 AM by JAG56Cad »
Jose Gomez
CLC Member #23082

Offline RobertM

Re: Timing chain question ???
« Reply #8 on: September 25, 2019, 08:23:05 PM »
It's threads like this that make me really respect those of you who can make sense of it.  I spent too much time on the baseball field as a kid, and didn't know just how much this stuff would interest me :)  I've learned alot the past few years, but you guys have a lifetime of knowledge. Impressive stuff. 
« Last Edit: September 25, 2019, 08:27:13 PM by RobertM »
Bob Melms
'54 60S
'95 Sedan Deville
'99 Eldorado (RIP 2018)

Offline cadman56

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Re: Timing chain question ???
« Reply #9 on: October 08, 2019, 07:08:59 PM »
Okay, I  will get lots of grief over this but I think you might be over thinking this.
Why not just install the chain with the dots on the chain sprockets pointing to each other like the 56 Service manual shows.  Button it up, plug the spark plugs and hand rotate the crank until you feel pressure pushing up against your finger in #1 plug hole?
Then set the timing marks on the harmonic balancer where you want them?  Then set the distributoe rin with the rotor pointing to the #1 cylinder plug wire hole.
there is another way to check to see if you have the engine in the compression stroketoo.
Good luck

Larry Blanchard CLC#5820
1956 Cadillac Coupe deVille (sold)
1956 Cadillac convertible (sold)
1956 Cadillac Eldorado Seville
1967 Cadillac Eldorado (sold)
1968 Cadillac convertible
1991 Cadillac Fleetwood Brougham dElegance