I was going to check/adjust my valves for the first time but I was wondering, a previous owner installed a racing cam.  Does that mean that I need to use a different setting for the intake and exhaust valves?

280 engine with lots of PO modifications installed in the 1980's

Round-top SU's 

Mallory electronic ignition

Sometimes the lash spec is different from stock.

For now just measure what you have on all 12 cold  and note max/min.

 

 

 The definitive answer is maybe. If you received any paperwork with the car, look through it and try to find the cam tag. It has the cam specs and valve clearances on it. Or, try to get the info from the P.O. or engine builder. Or, Take a look at the cam and try to find some identifying marks on it. Usually, these are found on the timing gear end of the cam. Using those marks it's possible that someone can identify the supplier and go from there.

 While you've got the valve cover off measure the current valve clearances and see where they're set and how close they are to the others. Maybe, just maybe, you'll find the clearances all over the scale and might come up with a reason for the poor test results.

I haven’t checked my clearance yet; however, I pulled the valve cover and went through the stack of receipts, letters, and post-it notes that were given to me with the car and here’s what I have:

1) receipt from Z Center of Clifton N.J.  to PO RS (I'm using the PO's initials) for swapping a cam, valves, etc. dated 5/1986.

2) list of vehicle modifications that indicates the installation within the past year of a High Midrange CAM with anti-float HIPO springs RPM Range 4200-7200 dated 7/1986.

3) receipt from Z Center for installing a customer supplied cam and set geometry dated 5/1988.

4) letter from Motorsport Industries of Orange, CA recommending in response to PO TV (yes, a new owner) inquire to install either a 10-2002 or at the far extreme a 10-2003 camshaft dated 2/1993.

5) Undated specification card and receipt (no purchaser listed) for a Chambers Cam arse 339i with cold clearances of 0.010 and 0.012 for the intake and exhaust.

I've attached an annotated photograph showing the camshaft a a closeup of the Chambers Cams card.

Can anyone identify this camshaft? Also, why would the "Chambers Cams" carb only list old clearances?

I tried looking up Chambers Cam arse 339I but the first and only interesting hit was about Tiffany Chambers's arse. Apparently a porn star. 

Lash on card is Cold lash. This means you can measure and adjust on your engine at room temperature. 

Stock Cold is:

Intake 0.008"

Exhaust 0.010"

Yours is a bit larger.

4 hours ago, Jeff Berk said:

I tried looking up Chambers Cam arse 339I but the first and only interesting hit was about Tiffany Chambers's arse. Apparently a porn star. 

Hi Jeff,

I did a google search for "chambers cams" Alexandria VA as well. Google is only as good as the info you give it. Very limited results as well. Sorry.

I also searched the Virginia State Corporation Commission  for Chambers Cams but didn't find anything. Doesn't mean that Chambers Cams wasn't a d/b/a (doing business as) and the parent entity was under another name.

As a side note, the font style of the card from Chambers Cams appears to be circa 1960-1970, so perhaps it was a mom & pop shop that were in business, but have since retired and closed the business, sorry for that news to you.

Wayne

 

 Googled R.C.Automotive (left side of tag). The EPA has them currently listed in the same address as the tag. Google maps, it looks like the office is located in a nice looking business plaza. Might be worth exploring that avenue.

I just picked up a feeler gauge and I could stuff the 0.008 under perhaps 3 of the cams. The rest were too tight to squeeze any of feelers in. I suspect that I'm either doing something really wrong or the engine was far out of adjustment.

I'm going to do a criss cross directory search on Chambers Cams on Monday when I can reach a library with a set of Hays chris cross directories.

thanks

Jeff

 Describe how you're doing it and we'll let you know if it's right or wrong. 

Each cam lobe has to be close to straight up to measure the lash. Look at the picture below.

An easy way to do this is to put the transmission out of gear and short the starter solenoid blade connector with the +12V starter terminal using a big flat screwdriver. (MAKE SURE IT IS NOT IN GEAR AND KEY IS NOT IN IGNITION).

Watch the cam rotate and stop when the desired lobe is up.  Oil will pump out of the head and eventually fill the head and drain out the rear right side of head so be prepared to wipe it.

If you remove the plugs, there will be less battery drain.

 

Edited November 23, 20186 yr by 240260280

I think I got this now.  I watched a video that was very helpful:

 

I found that using a socket wrench to rotate the engine (thanks to the video) seemed to work great after I realized I needed to take the car out of gear ; )

Thanks for the help guys. 

After you finish, double check every "mouse trap" spring to ensure it is clipped correctly. Wrenches can bump them off.