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#210459 - 08/17/08 11:40 am Trouble with Megacycle Cams  
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Due to crankshaft wiping out the original cams when it let go I had to install new cams in my T120 engine. Bearing in mind possiblity of moving into the Classic 650's class next year I decided to upgrade with Megacycle 520-X2's that have 0.375" lift.

I now find, with crankase assembled and barrel temporarily installed, that the cams foul the cam followers mad mad mad

Terry Perna of TP Classic Restoration says the way out of this problem is to machine the tappet blocks deeper to permit the cam followers to lift further and thus clear the cam lobes. I think this is an excellent solution, however, that the problem should never have ocurred in the first place and wondered if anyone else experienced this kind of issue with Megacycle cams? I know that I won't get any satisfaction from Megacycle Cams based upon past experience. mad

help

#210460 - 08/17/08 1:52 pm Re: Trouble with Megacycle Cams  
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John Healy Offline
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Boston, Massachusetts
Certainly not a problem with Megacycle cams and the checking and work has just begun.

This cam has the same base circle as the stock cam .812" but the tappet guide block was designed for .325" (plus a few thousandths for running clearance) so with .050" more lift (plus some additional .030" - .040" in case the tappet floats) you could certainly have a problem.

You should have also read in the Megacycle literature that you have to check the lobe to flywheel clearance. This needs to be at least .080" (or more if you plan a lot of high speed stuff like Daytona) as the flywheel flexes at least that much.

But your checking doesn't stop with the tappet guide block and flywheel. You have to check the valve travel in the guide to be sure the top collar has clearance on the top of the guide, valve spring stack height so the valve springs don't coil bind, valve to piston clearance, valve to piston's valve pocket clearance, and depending on the size of the valves you are using, valve to valve clearance on overlap.

This is not a "drop in" camshaft! It has many features of the Kenny Harmon #18 with about .020" more lift.

Not all tappets are the same. It is possible to find ones that are not as tall, or have been refaced thus giving a little more clearance. But I think Terry is right, you should find the tappets that give you the most clearance and remove any additional material from the block itself.

Be sure to have your tappets refaced before using them and use a proper camshaft lube on the lobes even during your "dry-fitting."


#210461 - 08/17/08 3:48 pm Re: Trouble with Megacycle Cams  
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Thanks for your response John and the advice given. However, most of what you have advised had been covered by Terry Perna who provides me with excellent help/advice. For example Terry warned me about possible cam lobe tappet block interference (Megacycle's instructions don't meantion this for the X-2 cam profile). Upon checking for this before assembling the crankcases, I did indeed, find that the tappet blocks needed trimming to clear. Also, Terry has advised me about the need to check for coil bind and clearance between the valve collar and top of guide (actually I was already aware of this one).

As far as trimming the stock flywheel is concerned, I am also aware of this requirement as it is in Megacycle's instructions for teh X2 cams and have done this on another engine. However, in this case, I am using MAP's after market crankshaft that does not have this issue.

The cause of my problem which I did not anticipate, arises from my suspicion that the X-2 Megacycle cams actually have a smaller base circle than stock if the 510 cams that came out of my blown-up engine are anything to go by. This, in combination with a cam follower that is taller than the others, has resulted in the fouling between cam and follower. I found this out by comparing followers and leaving out the tallest one as an experiment. Sure enough, after emoval of the offending cam follower I could turn the cam.

I do agree with you about all the checks that have to be done when retro-fitting after market cams especially with higher lift, but wanted to warn others of what I regard as a this serious deficiency with Megacycle cams IMHO - at least with the X-2s (510's do not has sufficient lift to be a problem).

Maybe Megacycle have just recently started making cams with a smaller base circle than stock and that is why it hasn't as big an issue in the past. I maintain that it is irresponsible for Megacycle to do this as it will almost certainly ensure that there will be an interferance between cam and follower as in my case. The very least they could do is to cover this possibility in their instuctions as you are on your own otherwise (count on zero help over the phone).

Still mad

#210462 - 08/17/08 4:29 pm Re: Trouble with Megacycle Cams  
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Jeff Covert Offline
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Jeff Covert  Offline
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Benton, AR USA
Jim Dour is an Innovator and a good guy, Why try to find fault with HIM?
When you build a Race engine the responsibility is on the Builder to know what he is doing and make all the appropriate modifications to the engine to make the Aftermarket Performance parts work together.
If you don't like his stuff Tell Him and or don't buy it. But don't knock a guy like that in a public Forum for simply supplying quality parts.


Jeff


Jeff Covert

#210463 - 08/17/08 4:30 pm Re: Trouble with Megacycle Cams  
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John Healy Offline
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Malcom: The base circle of this cam is the same as stock- .812"!

While Megacycle does mention that the 510-75 cams with .400" cam lift does require the modification of the tappet guide block your right they do not mention this for the x2. But with variations of the stock parts used (like your tall tappet) one could easily have one tappet or more hit the tappet guide block with a cam that has 60 odd thousandths lift more than stock.

So someone made a "tall" tappet and Megacycle is to blame?

With all due respect, tappets today are made in several countries, by several companies, not all having the original drawing! Variations, although certainly not acceptable in a perfect world, are inevitable.

This is why ALL of this stuff MUST be checked and re-checked!

I don't think the message is the people at Megacycle are incompetent (a bit aloof maybe), but it takes a lot of patience and practice to learn how to do use these bits and be successful. This includes making sure you have the correct tappets to start with. If your tappets were all the proper height we wouldn't be having this conversation. Megacycle would then be a hero!
j


#210464 - 08/17/08 11:08 pm Re: Trouble with Megacycle Cams  
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Malcolm, old pal, do NOT try to blame Megacycle for any of your problems. You were warned over the phone to check ALL of the above mentioned clearances; you made a comment that suggested that you didn't think you'd have a problem!!!!

Every clearance you reference is a standard checking point for a performance engine.

Jimmy and Barbara provide sufficient warnings for all your inadequate clearances!! :rolleyes:

#210465 - 08/17/08 11:55 pm Re: Trouble with Megacycle Cams  
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RHall-HCV Offline
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Charlotte NC
MALCOLM, HOW MUCH CLEARANCE DO YOU NEED? YOU COULD SEND THEM SOME OLD FOLLOWERS AND HAVE THEM REGROUND TO REMOVE SOME MATERIAL. WOULD BE GOOD TO HAVE FRESH FOLLOWERS ON NEW CAMS ANYWAY.


ROB HALL
HCV MOTORSPORTS
#210466 - 08/18/08 1:33 am Re: Trouble with Megacycle Cams  
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Houston Texas
Looks like I'm out of my league here.

Apolgies to all.

beerchug

P.S. Rob I am using reground followers - thanks for asking anyway

#210467 - 08/18/08 2:19 am Re: Trouble with Megacycle Cams  
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NO PROBLEM, ANYTHING TO HELP ANOTHER GOOD RACER


ROB HALL
HCV MOTORSPORTS
#210468 - 08/18/08 3:16 am Re: Trouble with Megacycle Cams  
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Jeff Covert Offline
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Benton, AR USA
Bodger,

I have built plenty of stuff and had it grenade on me but it wasn't the parts suppliers fault , It was mine for not having my duck's all in a row when I started.
Jim Dour, Tom Sifton ( I know Tom has Passed On), Alloy Tech, Johnson Cams and many others have been doing this stuff for 40 Plus years, (Longer than I have Been Alive) and they make parts that work and have been Race Proven Over the years.
I learned the Hard Way by building it and Breaking it, when what I did didn't work I asked, I didn't blame parts suppliers.
If it wasn't for Ted Hubbard and Mike Akatiff I would still be Scratching my Rear, But I was lucky to find the right guy's and learn what to look for early on If they weren't forthcoming with what they had learned the hardway I would have spent way more money and had alot more heartache over the years.
In short, I am no genius, I am a good Listener, sometimes BlindFaith can lead you in the right direction.

Jeff


Jeff Covert

#210469 - 08/18/08 11:16 am Re: Trouble with Megacycle Cams  
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Houston Texas
Quote:
NO PROBLEM, ANYTHING TO HELP ANOTHER GOOD RACER
Coming from a young fast guy that means a lot laugh

Hope to see you in action at Barber.

beerchug

#210470 - 08/18/08 12:21 pm Re: Trouble with Megacycle Cams  
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phantom309 Offline
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spfld vt
Sometimes it is the radius on the tappet that does not match the radius on the block.Free play should have been checked when you checked for clearence of the block guides and a simple file has worked fine for me for years to gain what I needed. Now I have a mill but the file does the same thing. bigt


Tim Joyce
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#210471 - 08/18/08 1:13 pm Re: Trouble with Megacycle Cams  
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Alex Offline
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I agree that with aftermarket stuff like this, it would place an undue burden on the manufacturer to imagine every possible scenario in which their product could be supplied. The megacycle cam I am running on my BEARS bike, for example, needed the case and the tappet guides machined, though I hardly had to remove any material from one case half and probably more than .040" from the other. When the original design didn't require a tight tolerance, there wasn't one, but with aftermarket parts, you may encounter this as a problem, which is what it looks like happened here.

I know it's aggravating, Malcom, I've been there, but all you can do is take your lumps and try to learn from it.


A smattering:
'53 Gold Flash
'67 Royal Star
'71 Rickman Metisse
'40 Silver Star
'37 Rudge Special
sixtyseventy Lightboltrocket road racer...and many more.
#210472 - 08/18/08 2:07 pm Re: Trouble with Megacycle Cams  
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Kent UK
Hey Bb,

Don't you apologise man, you are only guilty of expecting information on useage to be included in the box. There was a problem over on the Triump forum with the excellent Tri Spark ignition that could have been avoided with inclusion of full and clear instructions in the box. It isn't a new problem and it isn't rare. A standard sheet listing all possibilities included with every Triumph cam would have avoided the problem.

Tom and Jeff were a bit smart off the line in jumping on you like that IMHO.

Blapper redwine

#210473 - 08/18/08 2:32 pm Re: Trouble with Megacycle Cams  
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Jeff Covert Offline
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Jeff Covert  Offline
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Benton, AR USA
I respect your opinion Blapper, Didn't mean to come off smart, just realistic.
As Alex stated above, my current cases had to be machined out so the cam would rotate. I have had the same cam in a different set of cases and had to do nothing to it.
The British Go/No Go Gauge at the factory had a broad range on it.

Jeff


Jeff Covert

#210474 - 08/18/08 3:06 pm Re: Trouble with Megacycle Cams  
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Jeff Covert Offline
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Jeff Covert  Offline
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Benton, AR USA
Let's Lighten this up!

If any of you live close enough, come out to the Magic Mile at DuQuoin, IL next Saturday Night.

It's opening night of the Illinois State Fair and we will be racing on the Mile (hopefully with a packed grandstand). The Modern 450 Prosport class is Paying $10,000.00 and the Vintage Twins is Paying $2,500.00.
The Vintage Twins class is an Invitational only and will have the best riders and Fastest machines in the country. (All of them will be full of them Go Fast Parts we've been talking about).

A few of the guy's on the List are:

Mark Gibson with his 8 Valve Nourish Weslake Triumph, Mike Caves on his Harley XR 750, Frank Hardman on his 750 Yamaha, David Atherton on his 750 Norton, My brother Paul will be on my 750 BSA.
That's just a partial list, but if you know anything about Vintage Flattrack those are the names you pay attention to.

It's gonna be Fun!

Jeff


Jeff Covert

#210475 - 08/18/08 4:18 pm Re: Trouble with Megacycle Cams  
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Houston Texas
Blapper,

I had decided to take my lumps especially as all of the resident gurus seemed to be in complete agreement on this issue and to let it rest at that. However, since you have so kindly come to my defense, thought would add some points:

1. Megacycle instructions are excellent and very specific to the application. For this very reason I had thought that I had covered all the bases after rigorously reading the instructions, with the additional precaution (as advised by Terry Perna ) to trim the tappet blocks.
2. Based upon the reasoning that the 510 X1 cam has 0.401 lift, I had assumed that 0.375” lift wouldn’t pose any major issues other than stated in Megacycle’s instructions (wrong assumption I know now).
3. Technical assistance is not available from Megacycle to small customers like me based upon a previous negative experience with the lady who answers the phone at Megacycle.
4. I do feel that after market suppliers shouldn’t be immune from exposure on boards like this if they are unwilling to provide technical assistance for their products.
5. On the positive side maybe others will learn from a discussion such as this.

Thanks for coming to my defense Blapper bigt .

Regards,

Malcolm

#210476 - 08/18/08 4:26 pm Re: Trouble with Megacycle Cams  
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Blapper Offline
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Hey Jeff,

My mouth's watering - wish I could be there

Blapper redwine

#210477 - 08/18/08 5:11 pm Re: Trouble with Megacycle Cams  
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Jeff Covert Offline
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Jeff Covert  Offline
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Benton, AR USA
Hey Bodger,

I will give you that one, Barb is the lady that answers the phone and she will cut you off before you even start talking sometimes, she's hurt my feelings more than once.

Jeff


Jeff Covert

#210478 - 08/18/08 5:38 pm Re: Trouble with Megacycle Cams  
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phantom309 Offline
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spfld vt
The two cams are what I run. x-1 in. x2 ex. The x 2 has more clearence problem then the x1 because of the base circle even with less lift.Its a race motor and if I told you some of the things I have done to make it work ,you would sh-t. Fell free to call any time bodger.I was at the races this weekend but would have called back.Never assume check it. bigt Tim


Tim Joyce
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#210479 - 08/18/08 5:55 pm Re: Trouble with Megacycle Cams  
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Houston Texas
Quote:
The two cams are what I run. x-1 in. x2 ex. The x 2 has more clearence problem then the x1 because of the base circle even with less lift.Its a race motor and if I told you some of the things I have done to make it work ,you would sh-t. Fell free to call any time bodger.I was at the races this weekend but would have called back.Never assume check it. Tim
Thanks very much for the helpfull response Tim bigt . Interesting about the x2 having a smaller base circle than the x1 if I understand you correctly. That explains a lot!

Read on the other board that the Manx cases broke frown Bad enough but hopefully the rest of the engine is OK.

How did the Triumph do?

Thanks for the offer of helping me over the telephone. You have helped me before and I'm very gratefull for it.

beerchug

P.S. Made correction (had it bassakards shocked )

#210480 - 08/18/08 6:06 pm Re: Trouble with Megacycle Cams  
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T. Sharp Offline
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That's what you get for 'assuming'. The X-1 does have .401 lift--AT THE VALVE. The X-2 has .375 lift--AT THE CAM. Multiply by 1.12 and you get a valve lift of .420. The X-1 cam only has a cam lift of .355 to .358. eek

#210481 - 08/18/08 7:28 pm Re: Trouble with Megacycle Cams  
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T. Sharp Offline
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T. Sharp  Offline
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Nashville, Tn.
Malcolm, got your message, you're correct, the X-1 does have .401 at the cam. I still tend to think in terms of the old numbering system. The (now) X-1 was the 1046 with .460 lift at the valve. I can't really come to appreciate the new numbering system!
To my knowledge (unless you're holding out on everyone!), you were running the old 1060, now 510-65 or the very similar JOMO/Kenny Harman 15, now the 510-15. Both of which had around .355 lift at the cam and around .400 lift at the valve.
The X-2 was originally a modified 1060 with .020 extra lift, released in Jan.'98.
Either way, if you were running the #15 or the Johnson equivalent, by going to the X-2, you add .020 lift at the cam.
I've actually had to fly cut the flywheel to give adequate lobe clearance on some engines that were running the old 1060/#15 grind cams.
If you were running the X-1, you really were cheating in the Proddy class. laugh
Still, you have to check all the clearances when you make changes.

#210482 - 08/18/08 8:03 pm Re: Trouble with Megacycle Cams  
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Houston Texas
Quote:
If you were running the X-1, you really were cheating in the Proddy class.
Just to set the record straight - No I wasn't. I was running the 510-15's - a very modest streetable cam not that much different to the stock T140 inlet cam :rolleyes: . Well that's my story and I'm sticking to it laugh .

Now as to the future I is not letting on :p Although may have provided some clues already eek . But that's for Classice 650's next year since I can't run HW Proddy anymore :
(

Hope I clarified things confused

beerchug

#210483 - 08/18/08 9:58 pm Re: Trouble with Megacycle Cams  
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RHall-HCV Offline
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Charlotte NC
So its going to be classic 60 650? Sounds good, we will get to race together.


ROB HALL
HCV MOTORSPORTS
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