Timing cover questions

[AJs72K5]

For anyone not familiar, I have a BBC with a solid roller cam and a long water pump. Timing covers have been a challenge recently

With a Comp Cams roller button, the Milodon stamped cover that I first put on flexed, leaked, and ultimately the double roller timing chain was making contact. End play was within specs at a little less than .010".

Then I put on a Cloyes Quick Button timing cover and set it up to zero lash like the instructions said. However, the button was extended almost to the limit to set zero lash initially and I'm assuming that the button actually did make contact with the cam snout. Again, timing chain made contact with the cover.

With a long waterpump, can I run any cover? Are the outside clearance issues only with a short pump?

I ordered an Edelbrock aluminum cover. Are there any other good options? The Comp and CVR covers are three times as expensive. Opinions on whether they're worth it?

@folkenheath

 

[folkenheath]

AJ, I'm not sure what to say, I've always run the stamped ones and I've never had an issue. But you do always have to check for clearance. I usually put it on without a gasket or cam button and spin it over by hand and check endplay. If the timing cover was going to hit I have dented them in one spot before to clear. Then put the gasket in and the cam button without any silicone and check endplay. One endplay is set then I put a thin film of ultra RTV on, then the gasket, then another thin film of RTV, then bolt it down. And recheck endplay when you are all done too. I do put more RTV in the corners when I bolt the oil pan down later of course, and I like the one piece oil pan gaskets by moroso or felpro.

You also have to make sure you have the correct cam button, there are two or three different lengths of cam button, and depending on the style of cover determines which length you need. Some covers have a larger inside clearance by the cam button with ribs that need a longer one. Some are all recessed in the upper sprocket portion and need a short cam button, etc. The cam button needs to be the point of contact, always.

Many times I also run loctite and one of those cam bolt lock plates where you bend the tabs up, just for extra insurance.

 

[AJs72K5]

Weird, huh? Cam button was the "standard" 0.945 BBC button. I did almost everything you mentioned. I'll let you know on the new cover.

 

[6872xtc]

I am curious how this works out since I used the stock timing cover on my big block when I installed the roller cam. I even used a stock cover on my small block which is roller with a short water pump.
Both had the end-play work out fine, and as far as I know and hear, both have been fine.

 

[folkenheath]

I'm starting to think that any part that has the word "cam" in it, you just have to swap it for new on occasion.

I guess I never really answered your exact questions.

With a long waterpump, can I run any cover? Are the outside clearance issues only with a short pump?

I ordered an Edelbrock aluminum cover. Are there any other good options? The Comp and CVR covers are three times as expensive. Opinions on whether they're worth it?

@folkenheath

Yes you should be able to run any timing cover with the long water pump, the short pump is the one that has clearance issues as its almost touching the timing cover.

As for the more expensive ones, you usually get what you pay for, however, a timing cover is just a "cover", so as long as it doesn't leak and doesn't rub and doesn't flex too much, it does the job. With a roller cam the lobes are flat and not curved so you do need the cam button to control the endplay and therefore the timing when not using a crank trigger. However, the forces of the cam gear and the resistance of the oil pump should normally cause the cam to thrust into the block, so I've not had an issue using a stamped steel timing cover as it doesn't flex enough to matter. Although I wouldn't use a cheap thin stamped chinese cover. The milodon cover you had first is the same one I have on my 632. I've used the Proform chrome Chevy Bowtie covers with good success too, they are quite thick steel, and of course just stock GM covers.

Now, if you want to swap cams easily as you like to do then one of those two piece covers might make sense. Personally I like the 1 piece because it's less places to leak and I think some of the two piece covers are only for adjusting an adjustable timing sprocket (the kind you don't have to reclock the crank sprocket to change timing). Considering I always use that kind (I don't want my cam timing moving on me), I've never used a two piece cam cover, I'd use a jesel belt drive if I was that serious, but I likely wouldn't use one of those on a street car(you don't want a pebble in your timing belt), and I don't own any track only cars.

 

[AJs72K5]

Technically, I didn’t swap cams this time.

The one thing I didn’t check was clearance of the chain to the cover. I assumed the button wouldn’t let that happen. I’ll post up pics of the two victim covers tonight.

 

[AJs72K5]

Victim #1

Victim #2

 

[folkenheath]

Does the center piece for the aluminum one have the same mark from the cam button that's in the middle of the steel one?

The steel one has quite a recess in the middle. Depending on the shape of the aluminum center, it may need a longer cam button?

You can check the endplay with and without the cam button to determine your clearance.

 

[AJs72K5]

Does the center piece for the aluminum one have the same mark from the cam button that's in the middle of the steel one?

The steel one has quite a recess in the middle. Depending on the shape of the aluminum center, it may need a longer cam button?

You can check the endplay with and without the cam button to determine your clearance.

No, the Cloyes cover has the button integrated into the 2nd piece of the cover. It's effectively on a threaded stud that lets you set the endplay distance. There is a small circle on the cam snout where it looks like the button made contact.

 

[folkenheath]

Do you have some pictures of the timing chain in the block, and behind it?

 

[AJs72K5]

This is an older picture.

Here's the only decent pic I have of it sitting in this block. Same kind of timing set, but new for this build.

Comp adjustable timing set. Has a roller bearing built into the back.

 

[folkenheath]

Did the different covers require the different cam buttons, it appears one picture has the long and one has the short.

Also, are the sprockets lined up depth wise? Meaning if you put a straight edge on the cam sprocket face (without the chain) is it aligned with the crank sprocket or further out?

The engine is installed right? So the intake is on? Oil Pan?

 

[jaros44sr]

AJ, what if you get rid of the double row chain, seems like that is what hits on both examples

 

[6872xtc]

So do you believe that the problem is due to the thrust bearing design? Maybe that has moved the sprocket center out some?
They would just make the crank sprocket match.
I can not remember what brand of timing set I put in mine, but I would think that there isn't a large difference in the widths of double roller chains.

Would it be possible to press the outer part of the steel timing cover for extra clearance?
I saw a tip years ago about welding a large flat washer on the outside in order to reinforce the center for a cam button. Maybe that would help hold position after doing some creative work with a press.
I imagine that you are creative enough to understand what I am insinuating. I can describe more, but I don't know if this idea is acceptable to you, for this engine.
Some may see it as too redneck. You should still have plenty of room behind a long water pump, as Heath said, for this idea.

 

[AJs72K5]

Did the different covers require the different cam buttons, it appears one picture has the long and one has the short.

Also, are the sprockets lined up depth wise? Meaning if you put a straight edge on the cam sprocket face (without the chain) is it aligned with the crank sprocket or further out?

The engine is installed right? So the intake is on? Oil Pan?

Engine is still installed. Intake is on. Oil pan is on the floor. Cam and crank sprockets are pretty damn close to aligned

Good observation Heath.. figured out today with the new Edelbrock cover that it needs the short button. 0.945" was way too long. So, I went back to figuring out what happened with the Cloyes cover. My machinist and I came up with a couple of things.

1. The built-in button is too short. The threaded end was extended to the last thread to make contact with the cam (I'd already figured that much out)
2. Zero endplay, per the Cloyes instructions, is too tight. The cam bound up on the button. The end of the threaded shaft (what little was actually threaded) was cracked causing the chain and sprocket to walk around
3. I didn't measure precisely, but there's 1/8" - 1/4" of clearance between the chain and the cover on the inside

@6872xtc

So, here's the plan.... I took apart an old Comp button and swapped out the ends. Now it's too long by about 0.060" (if I measured right), but I can work with that. I'll take it back apart and have it machined. Reinstall the Cloyes cover with closer to .010" endplay

AJ, what if you get rid of the double row chain, seems like that is what hits on both examples

Engine is gonna make way too much torque for a single chain Jim.

 

[6872xtc]

Progress!! Good deal!

 

[folkenheath]

Are you getting rid of the weird cracked threaded design? Is there a hole you have to plug?

The reason I was asking is can you check endplay right now safely through the bottom? Can you get a straight screwdriver or something to gently pry the cam back and forth to check clearance without a cam button? The problem is measuring it would be difficult, you could measure the clearance easily with the center out of your cover I guess, but setting the actual endplay may be difficult to measure with the intake on.

I always run these double rollers...

Avon Progear BBC

They are very high quality, are a true double roller(not just a double chain), and they don't stretch out and wear so easily like most other brands do basically. They also have billet gears on both ends and a torrington bearing in the back. There is no way they can move on you either, there are several keyways for different timing adjustments, but you have to remove the crank sprocket to do it, so once its done, its locked down. I get them through my engine machinist.

 

[AJs72K5]

No. The button pictured is a replacement Cloyes button I picked up. I didn't get a pic of the cracked one. I guess that would have helped explain. The other one cracked/broke at the depth where the screwdriver slot ends, which is one thread deep. That was all the engagement I had in the threaded hole in the cover. Didn't realize it because I didn't pull it apart to check after I set depth initially.

At this point, I'm gonna run the Cloyes cover, but with the modified button threaded much deeper (almost completely) into the cover. There's three full turns of extension of the button in the cover. If I measured correctly, I should only be about 1/2 turn extended

 

[4X4HIGH]

For anyone not familiar, I have a BBC with a solid roller cam and a long water pump. Timing covers have been a challenge recently

With a Comp Cams roller button, the Milodon stamped cover that I first put on flexed, leaked, and ultimately the double roller timing chain was making contact. End play was within specs at a little less than .010".

Then I put on a Cloyes Quick Button timing cover and set it up to zero lash like the instructions said. However, the button was extended almost to the limit to set zero lash initially and I'm assuming that the button actually did make contact with the cam snout. Again, timing chain made contact with the cover.

With a long waterpump, can I run any cover? Are the outside clearance issues only with a short pump?

I ordered an Edelbrock aluminum cover. Are there any other good options? The Comp and CVR covers are three times as expensive. Opinions on whether they're worth it?

@folkenheath

That is your problem right there. You need to run a short pump OR weld a washer to the front of the timing cover to make it more rigid to keep the cover from flexing when the cam walks otherwise you end up with the issue you're having.