Megacycle Cam 564-390

[ericpritchard]

Does anyone have any experience or information on how to set up a Megacycle 564-390 cam for a widecase 350 race engine? The cam is based upon a Norris grind and no longer made by Megacycle. The spec sheet from Megacycle is not consistent with the cam, so any help would be appreciated.
Eric Pritchard

[Eldert]

Hi Eric

Megacycle had the 564 390 for a while that was a Norris profile with .390 lift
this megacycle cam has the lobecentres way off . something around 95
if i remember correctly given timing was 51 / 77 , duration 308 and L.C. 103

Eldert

[ericpritchard]

Thanks for the info. The spec sheet states IN 51/77 EX 77/51 (open/close) with lobe centres IN 103 and EX 103 at 0.020" checking clearance.
The best I've managed so far is IN 61/46 EX 65/56 with lobe centres IN 83 EX 95 at 0.020" checking clearance.
There seems to be some doubt (at Megacyle, that is) as to exactly what the checking clearance should be...0.040", 0.020", 0.006"/0.012" or zero!
Also the spec sheet states valve lift at 0.416", but it measures 0.361" (at the valve tip).
Any thoughts, ideas welcomed!
Eric Pritchard

[Eldert]

Hi Eric

i found my old timing notes
i took the readings at 1 mm lift with zero lash
intake opens 49 closes 52 duration 281 degrees L.C. 91.5 degrees
exhaust opens 47 closes 54 durations 281 degrees L.C. 86.5 degrees

my combined lobecentres are 178 degrees and so are yours

Eldert

[ericpritchard]

Many thanks for the info, Eldert. Very much appreciated.
Back to the shop...and I'll give it a try!!
Regards
Eric