I'm having problems with my timing gears

[lesingepsycho]

2 Problems
1st problem: The woodruff key in my 1275 crankshaft seems to be cocked. It has a big front to back taper that is stoping the crank sprocket from seating all the way back to the block. My question: Is the woodruff key removable? If so, how? I couldn't get it to budge and I figured the crankshaft was not a good place for "bigger hammer" tactics. :hammer:

2nd problem: The camshaft sprocket seemed to bind against the new cam retainer when I torqued it down. Is the cam sprocket supposed to bottom out against the camshaft? Is there supposed to be a spacer or something that I forgot? Or perhaps the new retainer's hole is just to small for the shoulder of the cam sprocket to pass through? If the hole in the retainer is too small should I enlarge the hole or narrow down the shoulder on the cam sprocket?

Thanks,
JACK

 

[histerical]

The woodruff key is round on the bottom and will rock back in its slot . You can take a small hammer or drift and tap the back down so it is parallel to the shaft. The trick is to slide the sprocket on so it doesn't hit the front of the key and rock it back.
Bill

 

[jlaird]

And yes the cam gear goes all the way in and seats against the cam.

Do not hesitate to tap the key out with a small hammer and a punch. It then can be cleaned and sanded a bit on the sides to make it fit correctly.

 

[Hap Waldrop]

Against the cam thrust plate.

 

[lesingepsycho]

Thanks for the responses. I'll give it a go tonight. Since I'm using a new cam, new crank, new cam retainer, and all new sprockets, I was hoping to put them on and straight edge them as the manual(s) suggest so I can do any shimming needed before they go back on for good with the chain.


JACK

 

[jlaird]

Yes thrust plate of course Hap. Sorry about that. With the crank gear in place and the chain on, the cam gear will only go one place, held in proper alignment but the chain.

And of course the crank gear installs flat against the crank with a very large bolt holding it there. Keys on both gears of course.

 

[lesingepsycho]

OK. My apologies but I have to clarify because I'm not sure what is being called the "Thrust Plate". In my lexicon, there is a camshaft, front engine plate, camshaft retainer, and camshaft timing sprocket. Are we calling the camshaft retainer the "thrust plate"? Let me add a picture and see if that helps...

JACK

 

[lesingepsycho]

When I did the final assembly, I added assembly lube between these two surfaces and then the cam moves freely.

 

[jlaird]

Looks like you got it. Hope those dots on the two gears line up. Check that with a straight edge about three times. It is so easy to be a tooth off.

 

[Dadandson]

IMHO, I think you should use a timing wheel and set the cam to crank exactly correct to the cam manufacturers spec. You can get cam shaft keys that are offset, Winners Circle, to get it just right. Sometimes the dots are off!

 

[jlaird]

Hmm, never saw the dots off. But I sure have gotten em on wrong.

 

[Hap Waldrop]

Yep, I agree with Tim, I put a degree wheel on everything, but then again, I'm often sending a engines halfway across the country, so no room for uncertainty.

 

[Guest]

And yes the cam gear goes all the way in and seats against the cam.

Do not hesitate to tap the key out with a small hammer and a punch. It then can be cleaned and sanded a bit on the sides to make it fit correctly.

Not to step on anyone's toes, but I'm strongly against any sanding of keys or their coresponding keyways. Woodruff keys fit snugly for a reason. Too much clearance and the crank will become junk shortly as the balancer is allowed to work back and forth wallowing out the keyway (I've seen this happen before).

Not to mention it makes it easier for the key to move out of place when installing the balancer.

You don't have to tap it out, just use a hammer to tap it flat and you'll be good to go. Brass is best; hardwood next, but if one is carefull, you can apply direct blows w/ a regular hammer.

If you have to "sand" a key to fit, then you have the wrong key.

 

[jlaird]

You obviously have not see some of the keys I have.

All nasty rusty and burs where some DPO has banged on them hard.

 

[BuggerAll]

If you are taking the trouble to build a performance engine, it makes no sense not to control the cam timing. Best solution is the vernier sprocket, in terms of compromise between price and ease of adjustment. The procedure is easy - read it in Vizard or any engine building book. ALl you need is a dial indicator and a degree wheel. But without dialing in the cam, you can be off 12 degrees either way. Plus, a lot of performance cams work best when installed with a couple degrees advance over manufacturer's recommended figure - like no. 1 full open @ 104 ATDC, rather than 106 or 108 -

 

[lesingepsycho]

Well I did go to the expense of buying a camshaft that is turbo specific so my assumption is that they have already ground this cam up to run optimally on a zero offset cam key. Am I mistaken? And if I am mistaken, how does one know what the best cam timing is? Guess and check?

Vizard does go on to say that unless you are going for the ultimate race performance, so long as you are "within about 2 degrees you are unlikely to feel the difference although a stop watch might". But 12 degrees off? Is that really possible? Do they even make/sell a 12 degree offset woodruff key?

So to me, the $300 camshaft should negate the need to spend another $300-$500 on an adjustable cam gear but please correct me if I'm wrong. I would much rather go through the trouble now than once the engine is in the car!

JACK

 

[dklawson]

I've never seen a cam out by +/- 12 degrees but I have seen them off by 4 degrees and acquaintances of mine in the U.K. have told me it's not uncommon to be off by 6 degrees using dot-to-dot.

I used an offset key when I put my cam in. It meant using the degree wheel and then ordering what I needed... so it wasn't fast. However, it was much less expensive than a set of vernier gears.

One thing I would have done differently is I would have selected a key that gave me 2 degrees more advance. Apparently this is a common practice by some in the U.K. The additional 2 degrees isn't for performance but to compensate for chain stretch as the components "break in".

 

[lesingepsycho]

Yeah, in fact, Vizard suggests that you go with extra advance to make up for chain stretch. Well, I guess, after listening to the input here and looking over Vizard some more, I'll be off to get a degree wheel tomorrow. I saw them at the local parts store and I need to pick up some other things there as well anyways.

JACK

 

[dklawson]

If you don't think you'll need the degree wheel often enough to justify buying one, download my PDF. Print out the wheel, glue to cardboard, cut it out and use once or twice as needed.

https://home.mindspring.com/~purlawson/files/DegreeWheel2.pdf

 

[lesingepsycho]

Don't fret everybody. I went ahead and timed the cam and it looks to be dead on.

JACK