I apologize ahead of time for asking such trivial/fundamental questions, but still playing catch-up on a lot of mechanical basics.



Since I assume excessive banging on the crank nose is likely discouraged, after the key slot has been thoroughly cleaned out and de-burred/filed, how do you decide where to draw the line on filing down/fitting the woodruff key? While popping it in the freezer beforehand would likely allow some installation latitude, I don't want it to jam halfway in using a brass mallet, and then have to drag out a sledgehammer to seat it fully (or pry it out and start all over, for that matter). If it's TOO easy a press-fit, even though it's captured, would it then be more likely to break/fail or widen/damage the keyway?



Also, still wondering if anyone has ever come across a substitute for the OEM reinforced rubber valvecover-stud/valleypan-bolt seal that shreds debris when removed?

6 VOLTS/POS. GRD. NW INDIANA

Daniel, theres not too much science in it, just put key in crank, replace if sloppy, i place light smear of oil on snout and draw crank pulley onto crank using long bolt, and remove with a puller! its definitly not advisable to drive on with mallet as i have had a pulley break through the 3 arms through the shockwave. The keyway fit to key is realistically about 002"-004" clearance, due to general wear etc. .000" would be good in a spaceship but not these engines, dont forget the pulley is about a size for size fit on crank. This is only my view and sure others can add to it one way or another. Regards bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Dan, it should take some effort to drive the woodruff key into the crank snout. It should not be loose. Support the under side of the snout for a little "feel good".

The damper should be an interference fit on the snout. We shoot for -.0006" if we have control. Anything over -.001" will be a bear to get on and off the crankshaft.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Thanks John,



Good info. As I will be using a rebuilt NOS damper that was never installed, I should likely polish the bore and check it with a hole gauge until it's ID is .0006" under the crank OD?

While it would be simpler to polish the crank nose, the next damper MIGHT be larger. I noticed my original engine's crank/damper fit was not all that tight, so either the crank nose was polished in the past, of the fit became looser just from mileage/wear?

6 VOLTS/POS. GRD. NW INDIANA

Dan, anything machined has a tolerance. Nothing is perfect. I have check Y-Block crank snouts @ anywhere from 1.2505" to 1.2515". The bore of the crank damper will have a tolerance also. So, some combinations might have as little as .0002" interferance fit while another factory combination might have as much as .0020". There will be a hugh difference in the amount of force needed to install or remove the damper.

I have noticed that the steel replacement dampers for the T-Birds have very little interferance, not enough IMO. Some will slide on by hand. This can be very hard on the woodruff key unless the damper bolt is kept very tight.

We have settled on the snout being .0006" larger than the bore of the damper as being a good balance.

I always apply anti-sieze to the snout when installing the damper. I also put anti-sieze on the threads of the puller and installer to save the threads. Good tools will last a lifetime if you take care of them.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

John,

Can anything simple be done to improve a loose damper fit (knurling, Loctite, etc.), without making it near impossible to remove safely?




6 VOLTS/POS. GRD. NW INDIANA

Dan, I suppose the crank could be knurled with a hand knurler. Look at the inside of the damper. It only contacts the snout over a short area. No point knurling where it doesn't hit.

Is the damper an NOS Ford piece or one of the replacements? What kind of fit do you have? Some interference or does it slide on?

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Permatex makes a product specifically ‘for relaxed’ hub clearances.  Part #68040.  I suspect Loctite makes a similar product.

Lorena, Texas (South of Waco)

John,



NOS damper, over-honed (tale of woe follows), now slides on and even wobbles a bit (without key).



Originally measured ID with snap gauge and same ratchet micrometer used to measure crank snout. Since machine shop was nearly an hour away (thus periodic trial fitting didn't seem practical), and their dial inside mic. reading didn't agree with my snap gauge spec., I stood by while honing was done and made frequent checks using my tools, assuming relative measurement/technique would eliminate micrometer variation/error. BAD IDEA! Didn't consider heat expansion due to honing procedure, or whether I should have used the max., not min. ID as my guide.

6 VOLTS/POS. GRD. NW INDIANA

It's official. I AM an idiot. Thorough examination of cheap chinese snap gauge reveals manufacturer forgot to grind a radius on one side. You'd think the measurement discrepancy would have inspired a closer examination. I obviously need a keeper.

Also, another example of the false economy of bargain tools. Remeasure with another gauge indicates I now have nearly .002" clearance.

6 VOLTS/POS. GRD. NW INDIANA