Updated: Help needed with cam timing-Ford 312 RR

Ford Interceptor 312 Y-block reverse rotation.  This setup substitutes 2 constant-mesh gears for the timing chain. There is a particular way to set the marks on the gears, and I'm hoping someone knows...thanks.

The 292 timing chain set up is odd.  the sprocket marks both face the Left side of the engine on set up and the chain has 2 marks on it for alignment with the two sprockets.   The Gear Drive your unit uses may have an odd set up like the chain drive.  (left side in engine talk is always determined when you are standing behind the flywheel looking forward towards the front of the car.   So looking at the engine from the actual front the Left side would be on the RIGHT, looking from the front.

IF you happen to have the cam card for the cam in your engine you should be able to rotate the engine with the heads off but cam connected and use a micrometer to measure the actual cam lift in relation to the camshaft and work backwards to the proper timing set up.   Kind of like Dialing in the cam in reverse.  But you need the specs on the cam.  Any New Cam for a 292 or 312 should come with a cam card as a starting point.   Then of course you would need to know the reverse rotation firing order.  

There is a Ford Y Block Forum, Y Blocks Forever,  Maybe one of those members will have the information needed?   Best of luck.

Mark

Bakground-engine went together great. Lined up "0" mark on cam gear with TDC punch mark on crank gear. 

As I began installing pushrods and rockers, and setting lash, it became increasingly difficult to rotate. Had rockers on/off about 5 times. It was very hard to do a compression test, and with 8 park plugs in it wouldn't turn over at all....so....

Off cam the heads, touched up by machine shop, reinstalled, same result.

That's when I went hunting for 312 RR cam timing info with no luck. Made a couple phone calls (thanks again Keno) and got some tips, but still no definitive answers. So...

Still without a 'cam card', I gathered my dial indicator and degree wheel and ended up retarding the cam by one tooth. Reassembled, it cranks over now even with plugs in. It should run. Will double-check the valve timing events before I button it up and try to start. 

But we're moving the ball down the field.....

As of July 6:

But I still need some 215 hp Interceptor cam data. Either rotation will work.

Frustrating, and have the Tahoe Concourse in 4 weeks. 

Picture 

MourningWood wrote: Yeah, well so far what I DO know is that when I line up the crank gear 'dot' with the "0" mark on the cam gear it does not turn over. So I have to dismiss the marks and try my degree wheel. But I still need some 215 hp Interceptor cam data. Either rotation will work. Frustrating, and have the Tahoe Concourse in 4 weeks.

They could/should be able to give you something for cam data from their timing cards.

It looks like they'll (Melling) still grind 312 cams, so they must have all the valve timing info stashed away somewhere 

Whether you'll be able to get info for your particular cam....who knows, but probably worth a phone call.

PS I'd say to check with Bosboy302, but I think you'd be talking to yourself 

You're right about that

But at least we're all trying  

The automotive normal rotation with it's 12 links between timing marks procedure also has #6 at TDC in firing position. Some other later much more popular engines have #6 in that position too when installing the cam/timing chain/gears.

None of us know as much as we probably think we do  

As you said earlier, moving the ball downfield..................... first and 10 on the opponents 30 yard line. 

Gotta score, a field goal won't do it.

Got it all buttoned up, painted, even futzed with the carbs (YH Carters) because, well, they always need some futzin'. 

Put the hose to it, fired right up, runs and idles great!!  Ran about 10 min. No leaks. 

Pop it back in tomorrow. Tahoe here we go....

Now, if I can figure photos I'll get some up here...

Thanks again for all the support.

 

"Now Biff..."

"Sorry Mr. McFly. I mean just starting the second coat"