THE ANGLE of the rocker arms lever arm is the issue - while the math tells you one thing the actual mechanics and the changing of the math ratio this to that becomes the thing that makes it not work -

the formulas for seeing the differences was not - this will work if you do that - the dynamics of camshaft grind technology is far more complicated than just a math calculus - size diameter of the roller and the short angle of the rocker arm you get into contact with the upper retainer - reason the 1.5 was used for the conversion it allows the large shovel top retainer not to make contact as the evo top retainer is 30 percent smaller maybe - i like lienweber cams they really work and the shovel Les is a solid cam so it has limits in the use but

years ago sifton cams was the deal was the 109 - its a great piece keep original springs and it has a ton of duration - the logic today is short duration to trap static compression < when the valve closes in relationship to piston location in motion - but because of the low lift near stock lift it worked - i still buy them in original boxes at times - you would not really know the bike has a cam as they say in it - steer your self to the comp cam read and pick based on what your looking for

 

It just came to me that the 1.43 rocker ratio gives a lower number than the 1.65 EVO ratio at the valve but at the push rod end the EVO cam would be like a high lift shovel cam at the push rod. When looking at these kits I did not notice any mention of rocker ratio or cam choice needed for this to work properly. With the shovel rocker box being enclosed one would need a box that has been cut open to check clearances. With V8 engines I have seen where guys have gone with too much lift with out other mods and dropped valves because of spring bind and retainer clearance issues.

I will have to call them and see if I can use a shovel cam with these kits.

If I can use the shovel cam with the EVO lifter would the larger roller be an issue?

 

Looks like the roller diameter effects the cam timing.

I talked to Dave at BMO products that are involved in the Velva kits and a EVO cam must be used. When it come to the rockers I can use the 1.43, 1.5, or even a modified evo 1.63 rocker.
Using the comp cam EVL 3010 using the 1.43 rocker I would get .446 lift at the valve.
He said that the Andrews EV27 was popular to use with this kit.

 

So if cam that is designed for 1.65 rocker ratio is run with a 1.43 ratio not only do I get less lift but I would also get a different opening and closing points and a change in duration too? So I think what you are saying to me if I want a bump up to choose a cam for a shovel and forget the conversion?

 

While i have installed the conversion the over all difference is in the cost last one it was 1500 for the stuff - and a shovel cam 450 lift needs finesse not a bolt in like they say < the bolt in is with no valve seals and mid lift upper retainers but your seat pressures are lower then a stock cam i like to run at least 95 to 105 on the seat what you find on the spring rimac - the open pressures are valve lift changes and coil bind on the spring set how close at full lift - and the pressures go 250 even 300 open with out special springs - hyd lifters are not impressed - a good shop should have the correct tooling to do the job - AMF was the reason we got the evo engine and the reliability - and common sense in the up grading part of the performance replacements - the original stuff was built for and like a farm tractor engine - yes it can be done and we do this all the time but lots of time and money goes into the making it right - in the end i found the andrews A2 while its not a bolt in like they say - it is an unleaded version of the early stuff we used and its no idle note very stock type idle and a mid range that fells like you spent the right money on the right stuff in just a better power curv all around no mid kick some want

you want .050 bottom of the top retainer to the top of the seal - you want .075 after full lift to coil bind - if performance springs are used pressures must be checked as the lifters are not todays - most times you do not have the spring heights making contact with the rocker box wall both sides should be checked with any cam over .450 because your travel distance is increased that makes the valve stem height much longer < this becomes an issue with top retainer to rocker box contact

the J is a bolt in just a tad bit difference in performance but its something - sifton approached this different then every one else lots of duration only .400 lift making it a real bolt in the longer duration make it soggy low then it spins up good mid to hi RPMs - it was what we had but not dressers we had light weight stripped down choppers with a bendix carb a mag if you had the money for one and we bought real gas at the pump < only thing better is the chicks were all available for crazy stuff

today they are grandmas hahaahahahahaahahhah

 

What cam and rocker ratio do you use on the on the conversions to the evo lifters?

 

Never did that most on the internet are way full of it and will say anything to make them selves sound important - care full what you read and think will work

evo lifters have a larger lifter roller then the 45 - all the flatheads - knuckle - pan and shovel shorter ratio can and does speed the roller on the cams how much IDk
but i have seen many shattered engine with ideas that did not work

its not one piece with get me what i want its a complete kit or shovel stuff no blending will work in the end

 

John, I thank you for taking the time on the topics I have been talking about. I think in the end I am going to keep it original or maybe use the "j" cam. I won't be highway riding, but my biggest concern is getting good lifter blocks and lifters which is one reason I had interest in the EVO kit. Those .003" over size sure are pricey and then I need to find someone to hone the blocks. (I know how to run the Sunnen hone machine but do not have access to one anymore.) But... I did see a Crane cam for the shovel that had longer duration on the exhaust, kind of like a stock cam but with .450 lift. I read that the stock cam had a longer duration on the exhaust to help cool the rear cylinder. Does it help, I do not know. This is my last project and do not need to make it complicated or more costly than it already is.

I wonder how good the quality of the Crane stuff is?

 

Chuck in an Andrews A2 and thrash the bejeezus out of it. Thing is, there is no perfect solution for any of this and overthinking and reading too much info will tie you in knots. ANY cam will make a Shovel faster, a HP here or there will make no difference to how it feels to your butt.
Crane stuff is fine as far as my experience with it can tell. I run an A2 (with solid lifters), 8.5:1 compression, worked heads and a TM40 Mikuni with waaay tall gearing, it gets off the lights nicely and cruises at 120-130km/h all day. Somebody somewhere will tell me how to do it better, that is for sure, but it does what I need it too and it didn't cost a shitload to get there.

 

@Spanners39 Well put, and Note...I bought a Shovelhead, Because I wanted a Shovelhead...Bought an Evo for the same reason.. No Twinkies tho!!!