Photobucket
Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Crank damper timing mark issue. Help?


A Poncho Legend!

Status: Offline
Posts: 44428
Date:
Crank damper timing mark issue. Help?


That sure seems like a lot to have slipped.

The cylinder heads are on the engine?



-- Edited by Carl Stevenson on Friday 4th of May 2012 10:22:59 PM



-- Edited by Carl Stevenson on Friday 4th of May 2012 10:23:16 PM

__________________

1966 Strato Chief 2 door, 427 4 speed, 44,000 original miles "FAKE_66"



Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

Setting up my initial valve lash tonight, and it appears that the outer ring on my crank damper may have slipped. If I rotate the engine to get #1 to TDC, visually the piston is well on its way down by the time my pointer ends up on TDC on timing tape. I applied the tape using the original TDC line on the damper. I do realize that my pointer is non stock, and will not likely register in the same spot as a stock pointer, but this seems wildly out. Should the damper TDC mark be at near 12 o'clock when #1 is at TDC? It is a used damper of unknown history and the rubber actually looks pretty poor.

The pointer in the picture is at about where #1 TDC is falling (without using a piston stop) Am I missing somthing here? Is a failed damper common?

 

DSCF3985.JPG



__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


A Poncho Legend!

Status: Offline
Posts: 44428
Date:

I am thinking you must have a damper for a different style of cover/pointer.

__________________

1966 Strato Chief 2 door, 427 4 speed, 44,000 original miles "FAKE_66"



A Poncho Legend!

Status: Offline
Posts: 44428
Date:

I seldom/never do any stuff with the later small blocks but didn't some of them have the timing mark in a different spot, about that far off what we would call normal?

__________________

1966 Strato Chief 2 door, 427 4 speed, 44,000 original miles "FAKE_66"



Poncho Master!

Status: Offline
Posts: 1708
Date:

Is this a  SBC engine and could the dampner maybe from a '80's 305 or 350? Those engines had the timing marks at 12:00. In that case you need an older style dampner.



__________________

'68 Parisienne 2+2 Convertible Matador Red (Resale Red but not for sale).



Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

So they did have dampers set to read at 12 o'clock, interesting Jc, thanks, I only ever knew of two different types and they were only ever different by about 10 degrees or so. The heads are on Carl. So I'll need a piston stop to find true TDC. Ever use one?

I'll probably just order a new Damper, a piston stop and a new timing tape and we'll go from there. Should I also grab a damper installation tool?

Cheers, Mark



__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


A Poncho Legend!

Status: Offline
Posts: 44428
Date:

I have never used a piston stop, no, so I'm not much good to you there!

When I needed to put my damper on the 327 I looked in the factory manual just for kicks. It says to use a hammer and a block of wood or something like that!

I did that with a twist. I shimmed the back of the crankshaft real hard against the engine stand so that when I was hammering on the balancer (with a wood block of course) I hopefully was not doing any main bearing damage. I have always heard that is why not to just hammer on the balancer.

__________________

1966 Strato Chief 2 door, 427 4 speed, 44,000 original miles "FAKE_66"



A Poncho Legend!

Status: Offline
Posts: 44428
Date:

I happened to see this on the Nova site just now. Wouldn't this be about the difference you have there?

cover.jpg



__________________

1966 Strato Chief 2 door, 427 4 speed, 44,000 original miles "FAKE_66"



Canadian Poncho Superstar!

Status: Offline
Posts: 4738
Date:

Nailhead wrote:

....just looking at the pic I'd say the pointer is about right for #1 TDC and the number ring has slipped about 30 degrees. Is that outer number ring tight ? If you got a old damper just compare from where the key way is to the line marked for TDC.


on my 427, 454 and older 350. the keyway on the crank points straight up for number one to be at TDC



__________________

sTevE

55 GMC, 70 Pontiac 2+2 rag



Uber Guru

Status: Offline
Posts: 3438
Date:

 Yes, the keyway will point just past the 12 o'clock position!



__________________

Vincent Jr.



Poncho Master!

Status: Offline
Posts: 2909
Date:

I have the same problem with the 350 in my blue SD rag. It's out ruffly 30 degrees also. It isn't a fluke and doesn't hurt the motor. I just dialed my timing light to make that my base line TDC. The motor runs great. I might fix it when I have more time but I'm having too much fun driving it to work on it. Paul.

__________________


Canadian Poncho Superstar!

Status: Offline
Posts: 6410
Date:

I know 67rag396's original damper on his 396 had slipped, and at the POCI shows there is usually a guy selling 1 piece dampers as the Pontiac ones were known to slip.    



__________________
70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 



Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

I tried all I could to get the damper ring to move, It won't move even one iota. Even side to side...nothing, no play, nada. So I decided to try to pull the timing tape off and perhaps reset it back on to what I've found to be my best guess at TDC. So when I pull it off and ruin it, I see some faint marks on the damper...right where my pointer was positioned. Looks like somone else faced the same situation with this damper and struck new marks. So, I think I may just stick with this one, buy a piston stop, find TDC and apply a new tape. I think this damper is setup for timing marks at around 12 o'clock, likely from an engine with the timing cover like on the left in Carls post...or the maks indicate the slippage over time.

And could a damper have actually moved this far?

Cheers, Mark

DSCF3989.JPG



__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


Canadian Poncho Superstar!

Status: Offline
Posts: 6410
Date:

why don't you just put on a new damper? 



__________________
70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 



Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

I probably will do just that Clint. No worries about being out of balance. Just trying to figure it out the mystery.



__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


Addicted!

Status: Offline
Posts: 454
Date:

First thing you should do is find tdc #1. Use a piston stop, if you don't have one make one from a spark plug. Once you have tdc established you can go from there



__________________


Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

All is well now. The damper that was on the engine was one that timed TDC around 12 o'clock. Replaced it with a Summit damper. Used a piston stop to determine TDC. It was actually slightly off the mark on the new damper. The crank keyway sits at around 1 o'clock for TDC.

New damper and tape, correct TDC position...

DSCF3992.JPG

Old and new comparing keyways at 12 o'clock to TDC marks (green tape)..

DSCF3991.JPG

 Thanks for the help.

Cheers, Mark



Attachments
__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


Canadian Poncho Superstar!

Status: Offline
Posts: 6410
Date:

keep in mind when using a piston stop, you need to check it both ways (crank going clockwise and counter-clockwise).  That's because as the crank rolls over the top with the piston at max height, there is a few degrees where the piston doesn't go up and down.  Mark it going clockwise, then couter-clockwise, and TDC is between the two marks.

 



__________________
70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 



Canadian Poncho Superstar!

Status: Offline
Posts: 8387
Date:

Yes, I did it both ways, thanks. Mind you, the only way to EXACTLY find TDC would be with the head off and a dial gauge. Cheers.



__________________
65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 


Canadian Poncho Superstar!

Status: Offline
Posts: 6410
Date:

cdnpont wrote:

Yes, I did it both ways, thanks. Mind you, the only way to EXACTLY find TDC would be with the head off and a dial gauge. Cheers.


Great, you know your stuff.   I would have never thought about when the crank rolls over the top, but I saw it on a show one day.



__________________
70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 



Poncho Master!

Status: Offline
Posts: 1637
Date:

a cam degree wheel is very helpful when finding TDC. handy at build to degree in the cam too.....

__________________

cutting a roof off a four door is NOT a convertible.....

65 Parisienne convertible.one of 49 built for RHD export market,402BBC, T400, 2500 stally, posi rear, upgraded brakes with front discs, FUEL FAST efi custom built by me.



Poncho Master!

Status: Offline
Posts: 2249
Date:

cdnpont wrote:

Mind you, the only way to EXACTLY find TDC would be with the head off and a dial gauge.


Yep, that is how I did it - back and forth .010" deflection and determine dead center - thankfully the pointer on my Moroso unit (looks similar to the one you have on your motor, Mark) was adjustable to get it juuuuuuuuuuust right.

Dave



__________________

56Pontiac  1956 Pontiac Pathfinder 2dr sedan, 496 - dyno'd 545 hp, stick shift, 4.11 posi - Hot Rod

  1964 Acadian Beaumont SD convert, 283 - factory 195 hp, Powerglide, 3.08 10-bolt - Cruiser

  2012 US-built crew cab truck - Daily Driver and Boat Trailering



Poncho Master!

Status: Offline
Posts: 1277
Date:

[edit]The three most common locations for the timing mark on the damper

The exact years of the type of damper timing marks overlap one another, depending on the exact application.

  1. The pre-1969 damper has the TDC line on the outer ring at the 2:30 oclock position- or 2º before the keyway centerline- i.e. the line is to the LEFT of the keyway, looking at the front of the damper or engine. The keyway is seen in the ID of the damper nose. 
  2. The damper used from 1969 to about 1984 has the TDC line at the 2 oclock position- or 10º before the keyway. You'll find that aftermarket dampers are the 10º type, as are the bolt-on tabs sold by the aftermarket, unless they're adjustable. 
    Warning Note: This includes the SBC 400, although the 400 damper is counterweighted because the engine is externally balanced, and the 1985-present 4.3L V6 with its respective 6.75" damper (raised outer lip) that has both a 2 o'clock and a 4 o'clock position (for some vans eg. G-series, Express, and Astro/Safari). Do not mix and match internal and external balanced dampers! 
  3. A third timing mark was used from (some) 1978 to about 1995, and nearly all 1984-1995 (exc for 1985-present 4.3L V6 and van applications). It is at the 12 oclock position- or 40º before the keyway. This damper uses a timing cover that has the tab welded on at about the 12 o'clock position - the timing covers with this setup had either the 6.75" (305 and pre-1985 90 degree V6) or 8" (350/5.7 only). Professional Products lists the years for this type damper line as being 1984-1995 and is a 6-3/4 diameter damper.


__________________

pontiax- (canadian pontiac X frame)1964 Parisienne 2dr. hdtop lagoon aqua metallic (Q)

 

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us
.
Support Canadian Poncho!
Select Amount:
<
.
.
.