gtogreen1969 wrote:
GR wrote:
850 man
David please don't make silly statements like you have just made, you know nothing about cam design so why would you say that the cam is to aggressive.
Maybe you can tell the people on this forum about this cam rate of lift velocity, acceleration, lift per deg and so on, if this cam is to aggressive how come
race cams live which are way more aggressive than this cam.
Phosphate coating is not necessary on steel camshafts if the Rockwell hardness is there Clive at Clive cams treats his cams, Clive being a good friend of mine, have talked about coatings on cams and if the hardness of the cams and follower are right not a problem.
May be you should ask the man what oil he used and what he told me this morning was he used a cheap oil to run it in.
The reason the followers have gone like that is poor quality oil or followers to soft or not ground correctly.
I with out a doubt grind more mini cams than any one in Australia at the moment I have 25 cams waiting to be ground and they just keep coming in so I must be doing something right.
As for oil I recommend GULF WESTERN I have been through the factory to see how they blend their oils and there motto is if there is a better oil on the market they will match it or better it,we run the oil to 130deg F to 9500 RPM in a rotary mazda way beyond the limits of a mineral oil and the bearings were like new when the motor was pulled down.(AND IT'S AUSTRALIAN OWNED)
The cams that BMC made varied as production went on the MK 1 S being the best as in steel used and heat treatment used from then on they went down hill as in MK 2 S and then the 1100S, but the A+ cam is an excellent cam to grind it is flame hardened and measures close to 60RC and the hardness is very deep.
One thing that you should not do is to wind your motor over and over to try and get oil pressure up, prime the pump and oil ways and fire it up that is the fastest way to get oil to the cam as the cam relies on splash to oil the lobes.
Winding the motor over and over rubs all the lube off the lobes, not good.
If a good assembly lube is used on the bearings during assembly a motor will run for 5 minutes or more with no oil pressure at low RPM.
Graham Russell
The only time David contributes to this forum is to try and put down other businesses especially yours.
The only time I contribute on this forum is when through hard evidence, engineering knowlage and experience over and over again, seeing the same outcome, I know that I can answer the question asked.
I have replaced 5 camshafts in engines this year that I have never seen before, that have been brought to my workshop for repair. Every time they are pulled apart I see the same results, and all have a common cam profile.
Removing the failed item, replacing with a different cam, a new set of lifters, radis ground correctly, lubricated with a generic assembly lube and all the other necessary cleaning & parts required fixes the problem.
Hi GR. Thanks for mentioning me.
I cannot see how you could comment regarding what qualifications I have regarding camshaft profiles considering we have never met. My previous employment history is unknown to you, my qualifications and the people I associate with also unknown. I don't know why you have decided to single me out, I never mentioned your name or business.
The camshaft and lifters in question has failed and the owner has asked for advice. I have given my thoughts. That is all.
As for oil recommendations, we use quality Penrite oil in our engines, its also Australian made and a known to be reliable, without causing catastrophic damage to camshafts.
& can you please explain how oil quality has any significance to camshafts in Mazda rotary engines?
