Sorry Ed, just remembered a post where some numbers appeared to be incorrect.
Olaf
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| I Believe Erson Screwed Up My Cam, Sent The Wrong One Or???? https://www.slantsix.org/forum/viewtopic.php?t=43343 |
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| Author: | olafla [ Sat Jan 22, 2011 6:26 pm ] |
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Sorry Ed, just remembered a post where some numbers appeared to be incorrect. Olaf |
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| Author: | emsvitil [ Sat Jan 22, 2011 6:35 pm ] |
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Quote: Sorry Ed, just remembered a post where some numbers appeared to be incorrect.
Olaf No problem. Without that link I wouldn't have know there was a special designation for the exhaust lobe........... 
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| Author: | Dart270 [ Sun Jan 23, 2011 5:01 am ] |
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Depending on how this was measured by them and you (with lash, w/o lash, what lash), duration numbers could easily be off by 5-10 deg. Just a thought... Lou |
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| Author: | speedy [ Mon Jan 24, 2011 6:59 pm ] |
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Well, I've finally gotten some answers and, ahem, clarification on a few things. To start with, for some reason I was figuring my intake opening figure of 2 degrees as being after TDC (which would be shown as -2), but soon realized it is in fact 2 degrees before TDC. Not sure why I was thinking it was after TDC as I figured the exhaust correctly (short duration cams intake opening and exhaust closings are shown with a minus sign)Needless to say, that in fact makes my intake duration @.050" 214 degrees. All other figures are the same: intake open =2 btdc close =32 abdc exhaust open =42 bbdc close =-9 btdc (9 after tdc) intake duration @.050" =214 degrees exhaust duration @.050" =213 degrees I talked to Eric today at Erson and gave him the low down. He agreed that the cam was off, being advanced when I specified straight up. He checked their info on the order, and confirmed that they used the RV15M intake lobe and the 212/295 Chrysler lobe with a 110 LSA. But as to how things were off he was perplexed, and not happy. He gave me the option of regrinding another one for me (he first wants to investigate as to why it came out like it did either way) or gave me advice on how I could set it up and run it which was as follows: Retard it 4 degrees. That would give me: Intake open= 2 ATDC (or -2) close = 36 ABDC Exhaust open= 38 BBDC close= 5 BTDC (or -5) And then to set the intake lash to .018" instead of the cam card specified .022" to get back some of the duration. I of course could tighten up the intake lash a bit more if I wanted? Say .015" or ?? This seems to put it in between an RV10 and an RV15...... How does this sound??? 
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| Author: | Jester [ Mon Jan 24, 2011 9:23 pm ] |
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hmm... Tell him to send you a new one, and you can send me your old one 
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| Author: | Doc [ Tue Jan 25, 2011 8:53 am ] |
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The Erson numbers listed above will get you a 8.2 DCR with 9 to 1 static compression ratio. You will also get a smooth idle with just a little "burble", no lash noise, tons of off-idle throttle response and mid range power. With this cam and set-up, (plus 2 additional degrees of cam retard) my Dacuda "Zing" engine pulls 21 inches of vacuum at 800 RPMs... 18 inches in gear at 600 RPM. DD |
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| Author: | speedy [ Tue Jan 25, 2011 5:50 pm ] |
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Quote: The Erson numbers listed above will get you a 8.2 DCR with 9 to 1 static compression ratio. You will also get a smooth idle with just a little "burble", no lash noise, tons of off-idle throttle response and mid range power.
Well, again, those characteristics are what I wanted and why I ordered an RV15/295, and being it's messed up and not one, I'll be yanking it out tomorrow and sending it back, I have no idea what it is, or how it would perform, and don't want to be a guinea pig to find out! I just hope they can regrind me a correct one and get it to me quickly. Thanks
With this cam and set-up, (plus 2 additional degrees of cam retard) my Dacuda "Zing" engine pulls 21 inches of vacuum at 800 RPMs... 18 inches in gear at 600 RPM. DD |
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| Author: | emsvitil [ Tue Jan 25, 2011 5:54 pm ] |
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Erson better be paying shipping........ |
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| Author: | emsvitil [ Tue Jan 25, 2011 5:55 pm ] |
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Just curious, but where is Erson located? |
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| Author: | emsvitil [ Tue Jan 25, 2011 6:06 pm ] |
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I think I figured it out. goto page 95 http://www.mrgasket.com/ftp/pdf/erson.pdf The RV15 Hydraulic version has a duration of 214 @ .050 and lift of .288 (which is very close to your .290) If this is the case, it's an unusable cam with both hydraulic and solid lobes |
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| Author: | sandy in BC [ Tue Jan 25, 2011 6:23 pm ] |
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I seem to remember Carson City NV........ |
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| Author: | speedy [ Tue Jan 25, 2011 7:58 pm ] |
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Quote: I think I figured it out.
I saw that in the catalog I have and mentioned it to them, they said that was'nt the case. Who knows. Right now, I'm about fed up with the whole thing. I've got everything ready to go, was supposed to have the engine assembled this past weekend and be putting it in the van this weekend and button it all up. I waited 3 weeks for the cam, and it ain't right. Severely ticked off. I should just have gone with the Comp Cam or the Isky off the shelf and been done with it. Would have been just fine, and a heck of alot better than what I had. I got no business with this numbers crunching custom grind stuff...too much splitting the atom for me. It's one thing to do this all at a leisurely pace, but in the winter, in a shed with motorcycles and gravel drive and it's your daily driver and yadda yadda yadda....I need a break!! goto page 95 http://www.mrgasket.com/ftp/pdf/erson.pdf The RV15 Hydraulic version has a duration of 214 @ .050 and lift of .288 (which is very close to your .290) If this is the case, it's an unusable cam with both hydraulic and solid lobes  ....Oh well, I knew better 
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| Author: | emsvitil [ Tue Jan 25, 2011 8:50 pm ] |
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Ok, new theory. Now I think it's a RV10 intake. Same lift as RV15 @ .290 The exhaust lobe was made for the .904 mopar lifters, so the duration specs would agree with what you measured. The RV10 and RV15 lobes were designed for the smaller .842 chevy lifters. My theory is that you will get more duration if you're using the .904 mopar lifters........ So I did some searching...... Quote: did this to a GM 289 casting block . The cost near me was $ 400.00 for the lifter bore Bronze bushings and block machining. The Comp Cams .904 lifter price was only about $ 125.00 more when I did this. This .904 lifter is on a standard cam core and like UDHarold stated, I did see 2 to 3 degrees more valve timing.
from here:http://www.speedtalk.com/forum/viewtopi ... =1&t=12774 Lift won't increase because of the lifter diameter, so it would stay at .290". I don't see a 4 degrees increase being out of the realm of possibilities........ Look at the picture at the top of this page: http://clubs.hemmings.com/clubsites/MTF ... _stock.htm And I think you can see that a larger diameter lifter will rise sooner and faster with the same lobe. |
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| Author: | Joshie225 [ Tue Jan 25, 2011 9:29 pm ] |
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If the lobe is for a Chevy lifter a larger diameter flat lifter will not change the duration. Ignoring the lifter crown, the .842" lifter already appears as a flat plane to the cam and a larger flat plane changes nothing. A larger diameter lifter allows changes to the cam lobe which gives a greater rate of lift without the cam-to-lifter contact point running off edge of the lifter. This is why mushroom lifter cams were popular. This is a one-way relationship. Changing the lifter allows a change to the cam. |
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| Author: | emsvitil [ Wed Feb 02, 2011 12:14 pm ] |
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Did Erson figure out what they did wrong? |
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