I just recieved my NOS (early 60's model) Isky roller cam for my MEL 430. Man is it purty and shiny and stuff . This cam was ground for 1.5:1 ratio rockers which Isky used to make about two million years ago. The lobe lift is 338 and with 1.5 rockers the valve lift is 505. The question is this, since there are no 1.5 rockers left on planet earth for this engine (or an FE which will work), can I use my FE adjustable 1.76 rockers? This would give me a 595 lift at the valve. FE rockers by-the-way, are interchangeable with MEL engines. Now, I know that I will need to check the valve to piston clearance and may have to cut eyebrows into the pistons, but will this new rocker ratio change anything else like valve timing, overlap or something else that would likely desinigrate my presious MEL upon start up ? Beep
By-the-way, I contacted the ISky service desk via their e-mail and got zilch as a response. I called them and got the cold shoulder by some ***hole who said "Ford never built a 430, you have a 429". At that I hung up. God I hate people who aren't even old enough to be working for a speed shop, much less be talking with the public. Grrrrrrrrrrrrrr, but maybe I'm just gettin old Beep
Should add just a little bit of duration too, but as long as you check ALL the clearances and make sure the springs are adequate it shouldn't hurt anything. Although it may wear out the cam and lifters sooner than it would with the lower ratio.
You may have already thought about it, but you might check on the push rod clearances going up & down through the head.If the push rod holes are slotted, it may get close. worth the double check.
A spring's pressure increases as it's compressed--with the bigger ratio, you'll be compressing the springs more, which will create more pressure. Too much open seat pressure can wipe the lobes and/or bend pushrods. You also stand a good chance of running into coil bind on the springs. Going from 1.5 to 1.75 is a really big jump. Excellent point on the pushrods also possibly having clearance issues in their p***age through the head. Increasing the ratio effectively moves the pushrod closer to the rocker arm's pivot. You absolutely need to blueprint your rocker arm ratio, pushrod length and valve springs if you're making that big a jump in ratio. "Close enough" or "That should do it" isn't good enough. Gauges, micrometers and valve spring testers are required. -Brad
Damn someone just had to go and mention Isky,didn't they.Time for a short rant. The young Iskenderian Ie Ed's kid is a **** in the first degree. I called Isky a few years ago when converting a 318 poly to hydraulic cam and got the oh yeah,no sweat done it a million times thing,got a cam kit just for you . Got the kit and it had chevy locks and stock length pushrods and 440 lifters. Called 'em up and said hey the locks pushrods and lifters are wrong and Ed's kid told me well too bad and acted like multi grove locks were from another planet and told me that the pushrods had to work because they matched the lifters yada yada yada. Doohhh. Same ****, I had to hang up and handle it on my own. Got locks from Sealed Power and lifters from Neilson and had the pushrods made to spec. The lifters I got from Neilson were in Clevite boxes with the #'s peeled off but came to find out later (quite by accident) the lifters were 354 Hemis(the ones with a real wide oil galley groove). No more calls to Isky from me. It ****s to be all on your own on those deals.Check with Mr.Mac he might have some info or rockers for ya.He was a pretty hard core FE guy.Or maybe Uncle Scooby,he had some MEL stuff a while back. T.OUT
Thanks to everyone for their responses. It's too bad about "the young Isky" being an ***hole because his dad was a true gentleman and a diamond in the rough. He helped us out many a time back in the early days when the MEL's were brand new and few aftermatket parts were available. His prices were not cheap , but his help and service was excellent . With the new kids at***ude, no wonder people don't use Isky much anymore . Beep
i think you have to subtract the valve lash clearance before figuring total lift ie 338 - 030 = 308 308 x 1.75 = 539 actual lift or 308 x 1.5 = 462 actual lift using advertised specs i had the same problem with calling isky cams for old info you'd think they'd give a darn i have some cams with out id cards and asked isky to look up specs in old cataloges was told we don't have any old cataloges anymore if you mesure the real cam lift you'll get a better pict [i used a dail caliper its close but not perfect high point 1.695 low [side point] 1,385 so actually CAM lift is 310 - 030 =280 280 x 1.75 = 490 there was alot of bs back then about advertising lift dur etc to keep other grinders from coping their specs [sucessfully that is] my OPION is just stick it in don't worry john hope this helps
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