View Full Version : Timing Chain and Degreeing your Engine

08-31-2009, 02:57 PM
Y-Blocks were the lifeblood of the Little Birds. They made THE engine sound, that all the others tried to imitate, but never could.

The soul of all engines comes not from piston size or stroke, but from the cam, and cam timing. In other words, if you want to unleash those hidden ponies from your engine, the very first place to look is at your cam timing.

Cam timing depends on a GOOD timing chain. Did you ever give 'er gas, and feel that hesitation, especially in an older engine? 'Caused by a sloppy timing chain. They aren't all created equal and OEM chains stretch miserably after about 50k miles. True roller chain sets are the best replacement:
They look like doubled bicycle chain, and last > three times longer than conventional chains.

Cam timing determines your torque curve. Racers retard their timing for better 'high rpm' torque, because most of their driving involves 4-5,000 rpm. A stretched chain can retard cam timing by about 2*. The distributor is driven from the end of your cam, so a sloppy chain further aggravates starts from a light, and causes erratic valve and spark timing.

If you have an older engine and want to bring back that new engine feel, change your timing chain. Another opportunity is if you are already changing your water pump. Your timing chain is right behind the water pump. Most guys need a few hours, $150, and their driveway (on a nice day) or garage.

When installing a new chain, ALWAYS degree the engine timing. It's free and takes about an hour or less. Why degree? I mentioned cam timing and slop, but did you know some engines are DE-tuned from the factory by retarding the cam? Yep! That's why the 460 was such a dog.

Manufacturing tolerances stack up if you consider the keyway broached in the crank, the crank sprocket, the cam sprocket, and the cam. Four strikes before you install a new timing set.

We can adjust cam timing by using an offset cam key. Mr. Gasket sells them in 2*, 4*, and 6* increments. A better deal is to buy a timing set with seven slots broached in the crank sprocket, sold by many companies including Ford Racing. You just slide the sprocket on using the keyway you choose; -6*, -4*, -2*, zero, +2*, +4*, +6*.

Click HERE to learn how to degree your engine. (http://home.comcast.net/~simplyconnected/projects/CamAndTiming/Cam_Degreeing.pdf) This is a PDF file for you to print, so Acrobat Reader is required. If you don't have it, go to adobe.com and download it for free. - Dave Dare

Dan Leavens
08-31-2009, 05:52 PM
Dave excellent stuff, good read and printed for my technical file for future reference. Thanks for the thread and I would suggest others print as well.

08-31-2009, 06:49 PM
Dave excellent stuff, good read and printed for my technical file for future reference. Thanks for the thread and I would suggest others print as well.
Thank You, Dano. I hope everyone with a mid-life to older engine follows these instructions. The education from doing this job is VERY rewarding, the cost is inexpensive, and the outcome is truly remarkable and well worth the investment. Your engine response will feel new again.

BTW, this applies to ALL V-8's, regardless of brand or displacement. - Dave