Got my new roller cam installed in the block and set about setting the endplay. Well, I was going to try and use a stamped steel timing cover, but this doesn't seem to be the best idea. During the first fitting there was about 1/4" of endplay front-to-rear. Not good. Did some adjusting and got it down to about .003" or so, but any more leverage than just a touch resulted in the timing cover pooching out where the cam putton rides against it. Even after fitting the water pump with the aim of providing the timing cover a little reinforcement, there was a little too much "poochiness" for my liking. Looks like i need a cast timing cover.
Anybody have an idea or part number for a cast alum SBC timing cover that will fit under a "short" water pump without having to grind reliefs in either the cover or the water pump legs? (Also, something that doesn't cost $100 would be nice, too.)

I posted this in "Engine Mods," too.

 

I just put torrington bearing behind the cam sprocket, a roller cam thrust bearing on the front, and cranked down my stamped steel cover. It made a little bump, but I know everything's nice and tight. I tried a more "advanced" timing cover and had water pump fitment problems, so I gave up on that route.

Hope this helps. :)

-Noel

 

What kind of timing cover are you using? A stock GM cover is strong enough. Made-in-Taiwan chrome covers are not. I have a roller cam in my 71 and the stock cover worked fine.

You can also weld a piece of steel onto the front of the cover to stiffen it up.


[Modified by zwede, 1:54 PM 3/25/2002]

 

If you want to retain the stock cover reinforce it. I welded a 1/8th thick stainless slug inside the cover where the cam button pushes agains. It is like a big 1 1/2 inch washer without the hole. It is easy to mig or tig in and provides the increased stiffness for the cover and costs next to nothing.

 

Zwede, now you've got me worried. My setup has been running trouble-free for 20K miles, so I'm not THAT worried. Still...

How much strength does the cover have to have to simply locate the cam? The one I have appeared to be more than strong enough, and bear in mind I'm using a bearing thrust button (i.e., the button has bearings in it).

-Noel

 

Noel: If it's been fine for 20k miles I wouldn't worry about it. Not all Taiwan covers are weak.

 

If you don't mind the (IMHO) nasty gold finish, Miloden sells a cover with the "washer" already welded to the cover. The P/N is 65555 and Summit sells it for $32.

 

How are any of those ideas ever going to set cam end play? I guess if you don't care about your block or having fine metal shavings in your oil keep on doing your bubba ideas.

 

Excellent!

The cover I have is a leftover--a no-name Taiwan 2-piece unit from Summit. The Milodon sounds like just the ticket. Who cares how it looks?

I guess the real question is approximately how much force acts upon a roller camshaft trying to move it fore-and-aft when the engine is running? Like I said, I noticed quite a bit more resistance to levering the cam forward when the water pump is installed. "Quite a bit" being relative, I suppose. It doesn't LOOK like the rollers would slip off a lobe when the engine's running. I've never done the roller thing before and would like to get it together in such a way that I have something like stable ignition timing AND no worries about punching a hole through the timing cover or dropping a lifter off a lobe at 5,500 RPM.

Sounds like the Milodon is the way to go. Another guy suggested a Cloyes cast aluminum cover. I've tried cast covers before and, with our short water pumps, they plain don't fit--at least not without a pretty significant amount of clearancing with a grinder--because the mounting flanges are significantly thicker than a steel unit. I've even given a couple of cast covers away in the past.

Noel, I think I agree with the earlier poster. You probably have nothing to worry about if you have 20K on your installation. You done good...

 

I don't get it? end play is set the usual way: with the thrust button. Or are you saying anything but a high $$$ cast cover is bubba?

 

Some of the hi-per water pumps(GM 14011012 or Howard Stewart) have a extra lug cast in the bottom of the pump just for this problem. The lug will line up with the centerline of the cam. Drill and tap the lug for a 1/4-20 bolt. Then when the pump is installed you butt the bolt against the timing cover to keep it from flexing.




[Modified by Pete79L82, 5:16 PM 3/25/2002]

 

What I'm saying is you need an adjustable button and roller buttons are the best. You should have a torrington bearing behind the cam sprocket.

The bending in or out of a timing cover doesn't sound like the cam has been set with a dial indicator. If your cam is being forced back your grinding the coverbutton away and your upper timing gear is eating the block without a bearing installed. Or if you have a big gap the cam could move for and aft and you distributer gear suffers. I don't believe that stock stamped covers are ridged at all.

 

I am using a roller-style end button. (Crane P/N 99164). I've also asked several people who run roller camshafts about the need for a torrington bearing and the general consensus is that it's not necessarily required for a street/strip retroft application such as mine. If, however, I was building a full-boogie race engine I would certainly have that done.


[Modified by The Dude, 3:20 PM 3/25/2002]

 

The washer on the timing cover is not to set cam end play but to give a stable support for the roller cam button to be set up against. I also agree that .003 is too tight and around .008 comes to mind. This should be a slight clunk back and forth and not a bending of the cover. I also drill a small 3/32 hole behind the timming gear and into the block. There is a oil passage just behind the gear and this hole supplies pressurized oil between the block and gear.

 

Roller thrust button: Absolutely. I wouldn't run a roller cam without one. I'm not impressed with the nylon ones.

We disagree on the torrington bearing. A flat tappet cam is constantly being pushed against the block with a much greater force than a roller cam. Yet flat tappet engines run 100's of thousands of miles with no block damage.

I also disagree on the stock timing cover being to weak. I've had mine for over 2 years now driven daily to work as well as raced (road course, auto-x and drag race) and have had no problems.

I set my end play to the minimum spec by comp cams: 0.004".

 

This'll get sorted out. Reinforced timing cover is on its way. The .003" figure I tossed out earlier is not what I was considering running. It was a ballpark measurement based on preliminary, coarse hammering on the wobbly timing cover to see whether it could be brought close to spec. Remember, I had about 1/4" of fore/aft slop upon first fitting. It won't be final assembled or fired until I'm happy that the end play is in line with the cam manufacturers' recommendation.

 

I found that Milodon cover when I was looking for my roller cam. I ended upp going with a Summit cast cover and had to do a little grinding of the cover and changed out the water pump bolts. The price was comparable between the two.

How are you guys adjusting your end play with these roller bearing buttons? I bouget a couple from different manufacturors and could not get the adjustability I needed. I ended up going with a nylon button and grinding it down to what I needed.

 

I have the Cloyes aluminum cover with a roller button and Crane Cams billet timing gear and I had to machine of .050 off the face of the button to get enough adjustabillity.

The Cloyes cover works fine with the stock short water pumps. It only runs into problems when you install the high volume water pumps that use a physically wider impellar.