Stripped Water Pump Bolt

[Gary Lewis]

Strange!

I went to Rock Auto and see a Melling timing set for the M but it doesn't say whether it takes a single or two-piece eccentric. I think I'd call Melling.

I called them.

Survey says?

Single piece eccentric.

So it is safe to assume that for EVERY roller set, for the 351M, there needs to be a corresponding single piece eccentric for it to work.

BUT, find me that piece that works with the 351M/C?

I stumped all the techs today. Back to square 1. May just have to survive for the time being with the stock chain setup. BUT, I really want to install a roller, if not now, someday.

I just left Tim Meyer a message about this. If anyone knows it is Tim, of TMeyer. I see several timing sets on his site, but none say what eccentric they take. So we'll see what he says, and I'm sure he'll get back w/me.

[mat in tn]

I just left Tim Meyer a message about this. If anyone knows it is Tim, of TMeyer. I see several timing sets on his site, but none say what eccentric they take. So we'll see what he says, and I'm sure he'll get back w/me.

I did not use a roller chain assembly on mine figuring that with the amount of expected use it will see and the fact that by the time the std Cloyes wears out it will be time for a total overhaul. I don't know the reason for the difference in eccentrics, but my guess would be that the one piece is thinner allowing room for more chain assembly. I don't know whether my engine is in its second hundreds or possibly thirds at this time.

[Gary Lewis]

I just left Tim Meyer a message about this. If anyone knows it is Tim, of TMeyer. I see several timing sets on his site, but none say what eccentric they take. So we'll see what he says, and I'm sure he'll get back w/me.

Tim called back and we had a good conversation about this. He's never used a 1-piece eccentric on any of the C or M engines he's built, regardless of the timing set he's used.

And looking at the Edelbrock catalog he sees that the Windsor timing sets (7811, 7814, & 7820) discuss 1 or 2-piece eccentrics. But their 7821, which is for the M-block engines, doesn't. So he's pretty sure it is for a 2-piece. (And, he's pretty sure from looking at the part number that the Eddy is actually a Cloyes.)

But the proof is in the sprocket. Here's a pic he sent me of one of the timing sets he has on the shelf and you can see that it is for a 2-piece eccentric because of the raised area in the center. That's what the inner piece of the eccentric bolts up against, and the outer piece then fits between the inner piece and the sprocket itself.

So, what does your Eddy sprocket look like?

[AmericanSavage]

Tim called back and we had a good conversation about this. He's never used a 1-piece eccentric on any of the C or M engines he's built, regardless of the timing set he's used.

And looking at the Edelbrock catalog he sees that the Windsor timing sets (7811, 7814, & 7820) discuss 1 or 2-piece eccentrics. But their 7821, which is for the M-block engines, doesn't. So he's pretty sure it is for a 2-piece. (And, he's pretty sure from looking at the part number that the Eddy is actually a Cloyes.)

But the proof is in the sprocket. Here's a pic he sent me of one of the timing sets he has on the shelf and you can see that it is for a 2-piece eccentric because of the raised area in the center. That's what the inner piece of the eccentric bolts up against, and the outer piece then fits between the inner piece and the sprocket itself.

So, what does your Eddy sprocket look like?

Hey Gary,

I have the 7821--the instruction sheet is for the 7800 series. The only exception in the instructions to the 1 piece eccentric is the 7811--which can accept the 2 piece construction. But the 7811 does not work with the 351M.

When I called Edelbrock (and Cloyes, and Melling), they said all that the one piece is required for my fitment--with the obsolete part number I noted.

I would be interested in knowing if the 2 piece can be fabbed for the 7821. I assume the width is the issue because the sprocket is wider (thicker) than the stock sprocket (It looks). IF it works despite the official information from the manufactures we have been discussing, I may just keep it for a later replacement (running out of precious time right now and need to get it all back together). I would like an answer though because I am seriously curious and want to make it work.

Here are two pics of the 7821. It is different from your pic:

[Gary Lewis]

Hey Gary,

I have the 7821--the instruction sheet is for the 7800 series. The only exception in the instructions to the 1 piece eccentric is the 7811--which can accept the 2 piece construction. But the 7811 does not work with the 351M.

When I called Edelbrock (and Cloyes, and Melling), they said all that the one piece is required for my fitment--with the obsolete part number I noted.

I would be interested in knowing if the 2 piece can be fabbed for the 7821. I assume the width is the issue because the sprocket is wider (thicker) than the stock sprocket (It looks). IF it works despite the official information from the manufactures we have been discussing, I may just keep it for a later replacement (running out of precious time right now and need to get it all back together). I would like an answer though because I am seriously curious and want to make it work.

Here are two pics of the 7821. It is different from your pic:

I disagree. I think the two are the same. Yours, on the right, has the same raised land as the one from Tim, on the left, as pointed out by the red arrow.

So the easy way to answer the question is to bolt the new upper sprocket on with the stock 2-piece eccentric. If the outer part of the eccentric spins then the sprocket was made for a 2-piece eccentric.

According to Tim a sprocket for a 1-piece eccentric doesn't have the raised land, without which the outer part of a 2-piece will be captured and cannot spin.

[AmericanSavage]

I disagree. I think the two are the same. Yours, on the right, has the same raised land as the one from Tim, on the left, as pointed out by the red arrow.

So the easy way to answer the question is to bolt the new upper sprocket on with the stock 2-piece eccentric. If the outer part of the eccentric spins then the sprocket was made for a 2-piece eccentric.

According to Tim a sprocket for a 1-piece eccentric doesn't have the raised land, without which the outer part of a 2-piece will be captured and cannot spin.

https://forum.garysgaragemahal.com/file/n130191/Upper_Sproket_For_2-Piece_Eccentric.jpghttps://forum.garysgaragemahal.com/file/n130191/Upper_Sprocket_with_Arrow.jpg

I want to believe they are the same.

However, the side you cropped--isn't that the BACK of the sprocket? There is no DOT to line up on that side. If you look at my other pic, that is the side I think that faces outward because it has the aligning dot.

Am I making sense?

[AmericanSavage]

I disagree. I think the two are the same. Yours, on the right, has the same raised land as the one from Tim, on the left, as pointed out by the red arrow.

So the easy way to answer the question is to bolt the new upper sprocket on with the stock 2-piece eccentric. If the outer part of the eccentric spins then the sprocket was made for a 2-piece eccentric.

According to Tim a sprocket for a 1-piece eccentric doesn't have the raised land, without which the outer part of a 2-piece will be captured and cannot spin.

https://forum.garysgaragemahal.com/file/n130191/Upper_Sproket_For_2-Piece_Eccentric.jpghttps://forum.garysgaragemahal.com/file/n130191/Upper_Sprocket_with_Arrow.jpg

I want to believe they are the same.

However, the side you cropped--isn't that the BACK of the sprocket? There is no DOT to line up on that side. If you look at my other pic, that is the side I think that faces outward because it has the aligning dot.

Am I making sense?

Here is the side I think the way it goes on, with both upper and lower dots aligned--there are no dots on the other side of either sprocket.

I add: I like your idea--the only to know is to actually do it and see if it works. I may keep the setup just to see in the future.

BTW, a person can find loads of two piece eccentrics all over ebay for the 351M/400. CHEAP!

[Gary Lewis]

Here is the side I think the way it goes on, with both upper and lower dots aligned--there are no dots on the other side of either sprocket.

I add: I like your idea--the only to know is to actually do it and see if it works. I may keep the setup just to see in the future.

BTW, a person can find loads of two piece eccentrics all over ebay for the 351M/400. CHEAP!

I think you are right, I got the wrong side. But the other side has the raised land as well. So I really think it is for a 2-piece eccentric.

But you need to get another opinion. Perhaps find pics online?

[mat in tn]

I think you are right, I got the wrong side. But the other side has the raised land as well. So I really think it is for a 2-piece eccentric.

But you need to get another opinion. Perhaps find pics online?

the last photo shows a raised area offset for the eccentric. if it were mine, I would test fit it together and see how well it clears the cover and whether it rolls freely as it is supposed to. Possibly even mock install the pump in place and look for interference.

[Gary Lewis]

the last photo shows a raised area offset for the eccentric. if it were mine, I would test fit it together and see how well it clears the cover and whether it rolls freely as it is supposed to. Possibly even mock install the pump in place and look for interference.

Thanks, Mat. We are in agreement. But I wanted someone else to chime in.