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Author Topic: Let's talk about cams.  (Read 14798 times)

Jon

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Re: Let's talk about cams.
« Reply #75 on: March 19, 2009, 11:59:57 PM »
The final roadgoing Bullets built by the old uk RE ( not the Crusader based unit Bullet)
had modified cams,possibly the S type used in the scrambles engine, ran a compression ratio of 7.75:1 and had a claimed power output of 21bhp for
the 350, a contemporary road test showed a one way best of 88mph and
an average top whack of 81mph for the 350.Claimed figures for the 500 big head
were 27bhp and 92mph.
The contempoary Velocette Viper/Venom were a fair bit quicker so it might be
worth studying the velo M17/7 AND M17/8 cam profiles.
If anyone has an older copy of tuning for speed there are some interesting suggestions for making your own steel conrods using welded fabrication
I believe this was done on the GMS specials built in the 1950's.
When I tuned my 350 I fitted an R profile exhaust cam obtained from Keith
Burton and on his advice kept the stock intake,the piston used was an
original RE item and I think was about 7:1 throwing away the head gasket
and lapping the joint brought it up to just abou 8:1.Top whack improved
from just over 70 to just about 80.
Love all the suggestions for improving the engine you might just re-invent the
Continental GT with that sort stroke engine.

jonapplegate

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Re: Let's talk about cams.
« Reply #76 on: March 20, 2009, 03:18:35 AM »
You know at this point might it be beneficial to explore what can be done to reduce parasitic power losses and try to maximize the power transferred to the rear wheels.
 Does anyone have data on power at the engine as to power at the rear wheels? What can be done to minimize the loss?

Ice

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Re: Let's talk about cams.
« Reply #77 on: March 20, 2009, 07:34:57 PM »
 Full roller valve trains are also of interest to me not only because they reduce frictional losses but mostly because the tend to last a lot longer when properly designed and maintained.
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

ace.cafe

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Re: Let's talk about cams.
« Reply #78 on: March 20, 2009, 08:22:51 PM »
Full roller valve trains are also of interest to me not only because they reduce frictional losses but mostly because the tend to last a lot longer when properly designed and maintained.


If I can figure out a way to make them work with the .012" expansion ratio in our tappet clearances, they are definitely on the table.

However, if they cannot be used for whatever reason, our existing tappets are mushroom tappets, which if worked correctly can give lift rates very near to rollers, without the disastrous failure prospects of rollers.
So, I'm looking at both options.

There is a DLC coating available which may give the solution, if used on the mushroom tappet faces and cams. Looking at all the options right now.
I would love to get rollers in there if I can.
I'll see what Mondello has to say about it.

There will definitely be new tappets supplied with the cams, and I'm going to use whatever I can to get those cam flanks up as high as I can, as early as I can.
« Last Edit: March 20, 2009, 08:27:03 PM by ace.cafe »
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
http://groups.yahoo.com/neo/groups/AcePerformanceBullets/info

Ice

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Re: Let's talk about cams.
« Reply #79 on: March 21, 2009, 04:31:50 PM »
I wonder if its theoretically possible to make UCE hydraulic roller lifters work.
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

ace.cafe

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Re: Let's talk about cams.
« Reply #80 on: March 21, 2009, 04:51:29 PM »
I wonder if its theoretically possible to make UCE hydraulic roller lifters work.


No, we have no oil pressure feed to the tappet guides. And even if we could route some special lines to them, our oil pressure is too low to work them  properly.

However, there are some solid roller tappets which might be able to work, and I'm doing further investigation about them

Our current tappets are solids that look almost exactly like a valve. Narrow shaft and a big round head. Pretty large face mushroom tappets. And mushroom tappets can get very close to the performance of rollers, in terms of aggressive lift potential. And with our limited lift situation, we may be served just as well by the mushroom solid lifters like we have.
But, there is at least  room for improvement on the friction on the faces, which could be improved by a suitable roller tappet, or by using a modern ultra-hard friction-reducing coating such as a "Diamond-Like Coating"(DLC). And there are some other ceramic type coatings with can do similar purpose.

Basically, if we can get a good roller in there, I'll do it. If we are forced to use our existing style mushroom tappets, we aren't far off the performance of a roller tappet with those, and we can get them coated to do the friction reduction. And that may be the lesser cost option, with as much gain as we need to get.
The mushroom tappet is the next best thing, aside from a roller so it's a good performance system if you make a cam that utilizes the mushroom head diameter capacity to the fullest.
And our mushroom heads are much larger than the racing solid mushroom tappets that are still used by modern racers today. Bigger than the racing mushroom tappets sold for GM, Ford, Mopar, or even AMC. And the larger the head, the more like a roller it is, and the more you can get from it..
Our tappets really aren't bad. They just need optimization.
I'll use make them as optimally as possible, and grind the cams to make the most of them, if a roller isn't viable.
« Last Edit: March 21, 2009, 04:57:08 PM by ace.cafe »
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
http://groups.yahoo.com/neo/groups/AcePerformanceBullets/info

Ice

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Re: Let's talk about cams.
« Reply #81 on: March 21, 2009, 06:58:06 PM »
Thanks Ace. I do believe the friction reduction will be of real interest and value to all.
Weather building for permanence or longevity the benefits should outweigh the cost.
« Last Edit: March 21, 2009, 07:03:16 PM by Ice »
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

Chuck D

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Re: Let's talk about cams.
« Reply #82 on: February 18, 2013, 12:33:17 AM »
One more.
2006 Bullet Sixty-5 w/ Ace "Fireball 535" Kit (#10)
Ace "GP" head in the works.

'76 Honda CB550Four K(sold)


"What's so funny 'bout peace, love, and understandin'?"