Cams in 2 liter with DHLA 45's

[RC Hiatt]

My 72 spider was running great a few years back with the 45 DHLA dellortos and what were thought to be 11 mm pittatore cams with stock pistons and probably otherwise stock head. It has since been through another owner and two shops with unknown work done, and lately, it has been difficult to start and has some problems when on the pedal, so I have it in another shop, even though it has less than 10,000 mi on two rebuilds.

I'm now told the cams are shot, with a knife edge on most or all lobes. they do seem pretty sharp. Seem to have a 103.2000 number on one, which seems odd for pittatores, as I expected no part number.

So, now I'm stumped. I don't want to run stock cams with 45's, and I don't want to change the intake. Would a 105.48 euro intake and stock 105.2000exhaust work okay with 45's in otherwise stock motor? I have unknown reground cams in the parts bins that I could try, but not sure I want to experiment to that extent with outside help. . . and there is a bit of rust on those. Or I could have the "sharp" cams that use to work fine left in it and look elsewhere for the problems with starting and acceleration.

Any suggestions?

[Gordon Raymond]

You seem to have multiple problems here. I am guessing you are referring to the tip of the lobe as being knife edged? That is hard to do with any Alfa cast cam, reground, in 10,000 miles of use. What condition are the followers? If they were rough and scoured initially, they could eat up the lobes. Are clearances correct? Wearing followers, seat recession, stem stretch or valve face hammering can all cause this condition. Weak springs, or inadequate spring pressure with valve bounce can do all manner of damage to lobe profile. Finally, initial reground profile can be brutal enough to damage the entire valve train.
There are available today, cam profiles that work without pounding valve gear apart. I have collected many of the old Alfa racing cams in new condition, and sent them to WebCam for profiling. From there, Richard Jemison, Alfar7 here on the BB, has redesigned these profiles to provide better low end torque, with less overlap, and more high end HP, without the radical lobe shape that damages cams, followers valves, seats and so on. WebCam has the ability to not just regrind cams (resulting in a smaller bottom circle) but build up the lobe with material as hard or harder than the cast iron core. This is not a plating that may wear chip or pit with metal transfer, but a integral rebuild of the surface. It is not harder than new hardened followers, and does not chew up followers. The lobe profiles are computer designed, unlike the old race cams or current regrinds from most component suppliers. These cams work properly, and last. I would suggest you contact Richard, discuss your needs, and order cams from him based on his design contacts with WebCam. Most wise racers running vintage and sometimes irreplaceable Alfa engines, use these cams. Ask Richard for information on his customers!
BTW: Even ruined cams, with clearances, and reasonable compression and timing, will not cause starting issues. Performance issues, for sure, but usually not starting issues unless the overlap is so radical as to yield little starter spun compression.

[RC Hiatt]

Thanks Gordon. I have the car and extra head for parts in a decent shop to get all the details like cam timing and valve clearances done, but I will have to provide a different set of cams. Clearances were about .017 intakce and around .022 exhaust in a quick check. I've got reservations about using the stock or reground cams I have, so I went with IAP 11mm cams at half the cost of many others. Can't be any worse than the Pittatori's (which is what IAP use to sell). Wish I could afford the double cost of alternatives from Jamison or Ereminas, but the car does have a bit of rust and will be a great driver at my budget cost. My preference was Centerline, but they had only one cam in stock and I am in a hurry.

[180OUT]

Quote:

I'm now told the cams are shot, with a knife edge on most or all lobes. they do seem pretty sharp. Seem to have a 103.2000 number on one, which seems odd for pittatores, as I expected no part number.

[RC Hiatt]

Quote:

Originally Posted by 180OUT I've been puzzled about what you mean by "knife edge". The original Pittatore 11mm cams as supplied by Alfa Ricambi and other vendors years ago were pretty rough appearing when compared to Alfa OEM cams. The flat edges of the cam lobes were, indeed, quite sharp and the overall finish of the cams was not up to Alfa OEM standards. It looked like the cams were machined using old, worn out tooling. I sent the first set I purchased back because the machining looked too rough to even consider using. The second set was better, although the edge of the lobe was still sharp (knife edged?). I mention this because I ran these cams for about 20k miles without problem. What your mechanic may be describing as damage from wear may in actuality be the original construction of the cam.

[Sniady]

I would contact Richard Jemison. I did. Makes great cams. Powerful, and efficient.

[Gordon Raymond]

I probably mentioned the same advice earlier, but I'll second Sniady's recommendation.