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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		 Page 3 of 3
Author:  Charrlie_S [ Mon Feb 07, 2011 11:05 am ]
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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.
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
Doc, what do you have the lobe centerline at? I just got this cam, RV15M F212/295. My cam sheet says 106 intake centerline, but "dot to dot" comes out at 99 degrees. All the intake/exhaust, open/close numbers are in the correct relationship (everything advanced about 7 degrees, from the cam sheet).
Author:  Doc [ Mon Feb 07, 2011 11:20 am ]
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I get better over-all performance by retarding this cam grind a bit, doing that helps to even-up the overlap event and delays exhaust 'blow-down' event... it also delays intake close so you can run a bit more static compression and spin the engine a little higher.

Installed intake CL at 104 - 106 is about right. Check the overlap event at lash to see if it's a little advanced. (2-4 degrees more degrees on the intake opening vs ex. closing, in relation to TDC)
DD
Author:  speedy [ Mon Feb 07, 2011 6:24 pm ]
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I ended up checking the timing events @.020 lift (my cam card does'nt show them...or mention at what lift to check them) and while they were'nt the same as Doc's cam card link, they were close enough and after some debate, I ended up sticking it in, retarding it 2 degrees and calling it done. I could'nt wait any further really, and with what I'm doing with the van, I seriously doubt I'd notice any difference. :roll:
They ground it with 4 degrees advance to begin with, I figure my request was overlooked. No biggie. And I just accepted the fact that the numbers were slightly off due to Ersons tolerances and that the tolerances considering my tools etc was most likely the reason it showed being off. Anyway, the engine is in and running, currently at about 100 miles, in the middle of dialing it in. Vacuum is around 13-14 with initial timing at 0. I was getting ping/detonation at 10 btcd (vacuum reading was 15)....backed it down to 5 btdc, still a little ping...and now set at zero and seems fine. Have'nt gotten around to checking total and with vacuum advance yet. Will be checking that tommorow. Was hoping for better vacuum readings.....
Author:  Doctor Dodge [ Mon Feb 07, 2011 7:22 pm ]
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Try loosing-up the lash, try .020 In / .022 Ex.
It also sounds like the distributor need a recurve
DD
Author:  speedy [ Mon Feb 07, 2011 8:27 pm ]
Post subject: 
Quote:
Try loosing-up the lash, try .020 In / .022 Ex.
It also sounds like the distributor need a recurve
DD
I'll try .020 on the intakes as I set them at .015 initially. The exhaust is at .022 already. No telling what I've got for total and vac advance, will find out tomorrow
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