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Discussion Starter #1
Hello,

We are building a 496 chevy engine. We have order a cam from Ultra Dyne and did some measurement.

The chart of the cam says the following:

Ultra Dyne racing camsgrind no. CHB 311/321-12Rpart no. 502000 SN S60816intake exhaustDuration at 0,050280299lobe lift0,45440,4544open(BTDC)/close(ABDC)open(BBDC)/close(ATDC)timing events30° / 70°83,5° / 35,5°Duration at 0,020311°321°Cross valve lift 0,7720,772lobe sparration112°intake lobe center110°

We did 3 measurement (we double check it), at 0 degrees , 2 degrees advance and 2 degrees retard. look bellow for the results:

0° advanceintake exhaustopen(BTDC)/close(ABDC)open(BBDC)/close(ATDC)timing events28° / 70°79° / 29°Duration at 0,020312°318°intake lobe center108,5°2° advanceintake exhaustopen(BTDC)/close(ABDC)open(BBDC)/close(ATDC)timing events30° / 68°81° / 27°Duration at 0,020312°318°intake lobe center106,5°2° retardintake exhaustopen(BTDC)/close(ABDC)open(BBDC)/close(ATDC)timing events26° / 72°77° / 31°Duration at 0,020312°318°intake lobe center110,5°



What's the best way to go? We want to use 300hp nitrous!
We thought that the lobe center line of the intake should be at 110 degrees when timing at zero. But it's on 108,5 degrees and if we retard it 2 degrees it will be closer what the chart suggest.

regards

Freek & Alex (europe, Holland)


 

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Discussion Starter #3
This is better to read!!


Cam chart

Ultra Dybe racing cams
Grind no. CHB 311/321-12R
Part no. 502000 SN S60816

intake exhaust
Duration at 0.050 280 299
lobe lift 0.4544 0.4544

timing events open 30 open 83.5
close 70 close 35.5

Duration at 0.020 311 321
Cross valve lift 0.772 0.772
lobe separation 112
intake lobe center 110





0 advance

timing events open 28 open 79
close 70 close 29

Duration at 0.020 312 318
intake lobe center 108,5


2 advance

timing events open 30 open 81
close 68 close 27

Duration at 0.020 312 318
intake lobe center 106,5


2 retard

timing events open 26 open 77
close 72 close 31

Duration at 0.020 312 318
intake lobe center 110,5
 

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Discussion Starter #4
This is better to read!!


Cam chart

Ultra Dybe racing cams
Grind no. CHB 311/321-12R
Part no. 502000 SN S60816

intake exhaust
Duration at 0.050 intake 280 exhaust 299
lobe lift 0.4544 0.4544

timing events
intake open 30 exhaust open 83.5
intake close 70 exhaust close 35.5

Duration at 0.020 intake 311 exhaust 321
Cross valve lift 0.772 0.772
lobe separation 112
intake lobe center 110





0 advance

timing events
intake open 28 exhaust open 79
intake close 70 exhaust close 29

Duration at 0.020 intake 312 exhaust 318
intake lobe center 108,5


2 advance

timing events
intake open 30 exhaust open 81
intake open 68 exhaust close 27

Duration at 0.020 312 318
intake lobe center 106,5


2 retard

timing events
intake open 26 exhaust open 77
inake close 72 exhaust close 31

Duration at 0.020 intake 312 exhaust 318
intake lobe center 110,5
 

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Lets try again :p...................

280 int/299ex @ .050"
112 lobe sep/112 intake centre line (installed straight up)

IO 28
IC 72
EO 81.5
EC 37.5
............................................................................................

Installed 2 degrees advanced (110 intake centreline)

IO 30
IC 70
EO 83.5
EC 35.5

................................................................................................

Installed 2 degrees retarded (114 intake centreline)

IO 26
IC 74
EO 79.5
EC 39.5

Flip a coin as to where this cam will run best on you're combo.

FWIW i would install as per card (2 degrees advanced)
 

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Discussion Starter #6
Hello,

If you look at the chart you see that the lobe separation is 112 and lobe intake center 110. I alway's tought that if you put the timming gear at zero that the lobe intake center will be on 110. In other words, the cam has a built-in 2 degree advance. I'am i wrong???

If you look at measurements they are all a few dergees off. Is this normal?? ( doubele check all the measurements)

regards,

Freek & Alex
 

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If you take a look @ the valve events you've posted it will seem you've lost 2 degrees off the intake lobe @ .050" , installing that cam straight up will have intake cetreline @ 112 degrees , the card is calling for you to install 2 degrees advanced (110 icl) , in a perfect world '0' on that crank gear would have the cam sitting straight up (112 icl) , we don't live in a perfect world which is why we always use a degree wheel to set our cams.
 

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Is this the cam they recommended for you? I would want the exhaust to open a lot sooner for that much nitrous. The one Mark spec'd for me from Bullet Cams opens at 74* but its for a 565 and a 500 shot. Dont know if that matters or not but I would call and ask Mark about it.
 

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:confused:..................seems the cam in question opens 9.5 degrees sooner than you're Bullet stick (@.050")

:p
Talking about the exhaust lobe...his opens later. We are not the experts anyway, point being, He should call Mark at Bullet Cams (UltraDyne) and ask him instead of people on the net
 

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Talking about the exhaust lobe...his opens later. We are not the experts anyway, point being, He should call Mark at Bullet Cams (UltraDyne) and ask him instead of people on the net
Take another stab @ it , you might get it right next time.:p...................................got nothing against bullet cams , the ultadyne in question is a Harold Brookshire design no? , was'nt Harold Brookshire involved with Bullet @ some point?

Take a look @ those EXHAUST valve events again.;)

I've said nothing regards how this cam will perform in the OPs engine , only helped regard valve event timing , you mentioned a problem with this cam on this engine no one else , you may need some schooling on camshaft technlogy.
 

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Hello,

If you look at the chart you see that the lobe separation is 112 and lobe intake center 110. I alway's tought that if you put the timming gear at zero that the lobe intake center will be on 110. In other words, the cam has a built-in 2 degree advance. I'am i wrong???

If you look at measurements they are all a few dergees off. Is this normal?? ( doubele check all the measurements)

regards,

Freek & Alex
its good you checked everything, but don't give your self too much brain damage over the numbers. Remember if you look at the pointer to your wheel 2 different ways that will be .5 degree's change and how ever you did your piston stop will change it slightly. so just worry about what center line you choose to install it at. Like stroker says flip a coin . but the 110 Cl should be a good place to start. the 2 events that will have the most influence on how it runs will be IN close and EX close numbers. so start with what feels good to you and make changes later, the motor will tell you what it wants at the track. but really there is very little change on the motor on the dyno in just moving a cam around. big gains require a whole new shaft. cam company's grind them as close to what they are on paper as the can. Some company's give you a card printed from an actual measurement of the actual shaft, some give you a card that represents what it is in theory . I think thats what you are asking?

hope that helps a little, Paul
 
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