I have one of the Erson 280/270 RDP cam in my 225. I was wondering if anyone could tell me what the valve lash is supposed to be set at, these are .013 intake and .015 exhaust?

As I remember my Erson RDP cam like to be quite a bit looser. Since I can't remember the lash settings, I'll leave it at that. It was looser than Erson's spec.

I used Doc's method to find lash, it worked very well. Loosen until it gets loud on you, record the lash, tighten until it starts to miss, record the lash. Adjust it to the middle based on what you want. Do it hot.

CJ

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Part of Tyrde-Browne Racing

Hello Montana,

I have this cam running well in a 9.6:1 aluminum 225 engine in my 66 Valiant with a drool tube head. Runs great. I installed it at 104 deg intake centerline and optimized the lash. I am on a trip now and did not write down the lash numbers in my cam notes - oops. I write them on the car or valve cover once I find them and will look at that when I get home. If I forget, ping me next Th-Sat so I can make sure to look. IIRC, it was around 0.018" intake and 0.024" exhaust. It will idle better and make better low end power than with whatever lash specs Erson said, and you will not sacrifice any meaningful upper end power.

FYI, except for Mopar Perf cams, I have not found a cam company that delivered good lash specs on their sheet.

Lou

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Home of Slant6-powered fun machines since 1988

Thanks to CJ and Lou both for your help.

The cam was installed +4. Any suggestion on what timing should be set at to start with?

Do you mean ignition timing? If you have it installed at 104 CL, then you have already set the cam timing. I am assuming you measured that will degree wheel, dial indicator, etc?

As for lash, if you are wanting to set it to run, I would start with 0.018" int and 0.024" and that will be pretty close.

Best, Lou

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Home of Slant6-powered fun machines since 1988