Need a new Camshaft

Hello,
Its been a long time. My engine has been away for a while ie new main bearing bushes(bronze), crank balance, Combat oil/breather modifications and cam bushes. But the engine builder doesn't like the look of the cam for a number of reasons the key slot looks buggered and there is a nasty knock on one of the cam lobes. The engine is a combat so I suspect it has had an explosion at some time or other.
My delema is what cam do i get. Im leaning to the standard cam or Mega Cycle 560-N-R as Im not really into top end performance. As well, I noticed that Norvil voids warranty if you dont buy new cam followers. My engine builder says I dont need to buy new cam followers as they are in good condition and they have a flat profile anyway. Im inclined to believe him as he quite experienced in building race engines for classic bikes. As well who should I buy the cam from as I have read that quality of cams can differ.

Oh and incidentally has anyone put carrilo rods in their engine, the Builder notice that there is a bit of play b/w the rod and the piston pin on my new rods. He has noticed this on other carillo rods and suspects it may be normal and possibly this would occur with the standard alloy rods through expansion. Does this sound correct or do I have problems. The Pistons are a new set of italian GPM(or something like that)

Regards Bryan

Hey Bryan, I am having a Combat motor built too, Odd but that is the cam I am using. Also had the modification done to the crankcases and am going to use the Yamaha PCV one way valve, I have heard you want to have the lifters resurfaced, If they are in good shape. They don't need to have the radius cut for that cam I am told. But be sure they resurface the lifters if you don't use new ones. Good luck and ride safe, Chuck.

Bryan,
I have Carillo rods in my 750 motor with a 4S cam and gas-flowed and skimmed head with 32mm carbs. I can't say that I remember any unusual play in the rods, although mine came without the small diameter oil spray holes, which I drilled myself, starting from the inside and using the old top shell with the oil hole for a starting guide. I have had no problems with thee bike and it goes very well indeed. I generally have my lifters surface ground if I am using a new cam or even a different used-cam from the one that came out of the engine. I also note that there are various companies that will repair and regrind an existing cam to any spec you like, quite a bit cheaper than buying a new one.

Hey guys,
thanks. I spoke to the engine builder and he was going to resurface the cam followers. I also sent a question to Carillo regarding the play on the little end and piston pins. Though speaking to the engine builder again he just done a triumph motor with Carrillo rod and it was the same thing. So it now comes to which camshaft. Though I am pretty certain I will go for the stock Camshaft. Is Andover Norton Cams O.K? I think my engine builder will nitride it anyway for a little more hardness ( I think he said an increase of 5).

Regards Bryan

Hey Bryan, The reason I used the Mega-cycle cam was the guy building this motor said he thought they were better cams than the stock ones from Norton? I really don't know for sure but the 850 motor I had built a year and a half ago by a different guy wanted to use the Norton cam, So that is what is in that bike. It runs great and have never had any problems, And the 850 tows me and the warden around all the time, In fact this weekend we put over 225 miles on that bike in 90+ heat at speeds up to 70 and that was coming back from San Diego, So the bike was at that speed for over an hour and a half. I also know if you ask 10 mechanics their opinion you will get at least 11 answers. So my thinking is they are great cams and I bet the Mega-cycle ones are too, So did I confuse you? Sorry, Have a great day and keep the greasy side down, Ride safe, Chuck.

The story is that recentish Andover cams are cold-chilled cast iron and they're supposed to be OK. I haven't seen any debris on my magnetic plug this time...yet ! They also now provide a special lubricant for assembly.

If you decide to use the old followers, you should at least have them surface ground, ensuring that this is square to the bore.

Original followers were sand cast and had the flat stellite pad simply brazed on. They were known to often still contain casting sand - have a good poke inside and also the pads can become detached (although the worst may have been pattern parts made in the late 1970s). I bought a motor where this had occurred - it was not a pretty sight. More recent Andover followers are lost-wax cast and the stellite is spigotted.

To be honest, I would replace the followers and as Norvil have indicated, they and Andover are unlikely to consider future guarantee or goodwill claims where they haven't been replaced as a set.

If you decide to nitride, it would pay to find out what the original surface treatment was. Nortons once blamed a spate of failures on two processes not interacting well.

Bryan
I built a new engine 5-1/2 yrs ago and used Norvil's std cam. I used the red lube before firing and also Crane Cam's cam lube left over from my American car days. That was plastered all over the lobes and tappets/lifters and not disturbed until fire-up. Since then I've used synthetic oil and have no wear issues so seems they got the HT and material right. At 12,000 I stripped the engine cos I needed bare cases to do a frame alignment (another story) and the cam had little wear. It's on 16,000 now. I did of course get the tappets ground.

Hello All,
thanks for the advice. Ive decided to go for the standard cam and I purchased it from Andover a couple of minutes ago. I will also put loads of cam lube when I put it together.
I also got a response from Carrillo on the little end and I have attached it below. So I will get Russell who doing the engine work to check this out.
Cant believe the engine will be back, it's been 5 months( I know Im pateint but he is cheap and has a good reputation).
Getting close to having something that looks like a bike only have to build the electrics, seat and wheels which I will do my self ( got a wheel stand) get the fiberglass parts painted. Incidentally has anyone got a recommendation for a tank sealer for fiberglass tanks?

Regards Bryan

Bryan,
Carrillo sizes the small end hone on our Commando rods to .6885" I.D.
This is for .001" clearance over the stock wrist pin diameter of .6875"
(11/16"). Anything above this and the rods may need to be re-bushed.

Sincerely,
CARRILLO INDUSTRIES

Caswell on the tank sealer.