#21814, "If you know 420a heads, please read this and help me!!!! Fast420a also read"
okay i know this may be getting a little old for some people but please bear with me as your help may be able to answer some future questions.
I have stock cams that have been mildly re-ground. No material was added just a little ground off to give a bit more lift and duration. I upgraded the stock lash adjusters and followers with the PT Cruiser ones. the cams were done by a very reputable Co. in the area who is not known for turning out crap cams. They siad they have never had any issues with them on other 420a engines, so...
What i need to know from you head guys is what is the lash supposed to be on stock cams, or advice on what it should be with MILD regrinds. I have heard about 15 different stories on how they're supposed to be. I have virtualy no clearance on the intake side without shims and a shit load of clearnace on the exhaust side with each adjuster shimmed .060" and still having clearance (read ticking), some as much as .012".
How much clearance OR preload should i have between each roller and the cam base on each side?????
I am told that there should be between .020"-.030" PRELOAD on both sides, but then im told a little clearance is good to let the valves close all the way, so i have no clue at his point.
PLEASE HELP ME WITH THIS!! If no one knows for sure the info i need can someone give me a good shop/number who knows (works on) our motor in a performance way.
Fast420a - i got the crane shims you mentioned and they turned out to be .020" and .040", not .030" and .060". just thought you'd like to know....
USED TO HAVE...Everything you wish you had, and then some...
You are somebody special Tim, you matter! - from the admins (but nobody likes you, because your username is just like that other guy's, and you whine a lot)
#21815, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 0
Hmm. . .they must have changed the shims, I measured them out to .030 and .060 and the box says you can shim .030, .060 or .090 with them. Yours must be .020, .040 and .060, weird.
#21817, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 2
Im no cam expert as recent post will reviel, but from what i understand, they shave some off the bottom (increasing lift?) and take a bit off the sides near the top to make it more "rounded" off and not so pointy so the valve stays open just a bit longer(duration?). Does that make sense? Stock cams are 169@.050" intake and 204@.050" exhaust. Mine are 185@.050"I, and 223@.050"E. So not a lot of grind, but enough. They should give me about 10% more HP, so roughly 15hp. not bad considering they cost less than an UDP to have done.
USED TO HAVE...Everything you wish you had, and then some...
You are somebody special Tim, you matter! - from the admins (but nobody likes you, because your username is just like that other guy's, and you whine a lot)
#21818, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 3
anybody?
USED TO HAVE...Everything you wish you had, and then some...
You are somebody special Tim, you matter! - from the admins (but nobody likes you, because your username is just like that other guy's, and you whine a lot)
#21819, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 4
You should not have any play in between the rocker and the lash adjuster. It really doesn't make any sense if you think about it. All that can do is jack your rocker against the adjuster to beat hell OR the cam will hit the roller mid-air. The situation is exascerbated by the fact that you have power all the way to the rev limiter - so you can smack em around at 7300 RPM. All "play between the lash and rocker" will do is wear the cam and break lash adjusters and rocker arms...eventually.
I recently put in a set of Gude cams. The intake side sucked right up to the adjusters. On the exhaust side I noticed the same problem as you. The car is working fine, and it may have been that the adjusters just needed to pump up(I haven't pulled the VC after the cam job yet). It doesn't tick any more than it used to. As a matter of fact, it has the same exact tick as it used to with the original cams(I think I have a bad lash adjuster). I plan to replace the adjusters, and shim them if need be - eventually. And when I do, I'm going to make sure that there is no play. Thats what I sugggest you do.
My regrinds are are from Gude - I bought them used from Vinnie(thanks dude). Here's an observation that I made while recamming. I took a measurement of the longest part of the lobes and found that the new cams were approximately .2 inches shorter then the stock ones. Ok, now those numbers don't mean crap for reshimming. I didn't take the short side measurement, but it should give you a clue as to what to make up for stock distance. You already ground yours up - so here are the measurements of my stockers sitting on my lap. Intake and exhaust 1.175 inches. So here's what you do. Mic the shortest section on your regrinds, calculate the difference from stock, and divide that difference by 2. It's basically the change in cam radius during closed valve angle. That will give you the amount of shim to mimick the original lash seat height. It should give a good starting point anyway.
Good luck.
95 Eclipse RS : 5 speed Gude cams : Test pipe : CAI : Dual air horns : Kenwood KDC 5000 incomming - lower strut bars
#21820, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 5
ok.. nobody has answered my question.. how can you make a longer duration (longer lobe) and higher lift (taller lobe) without adding material? from my knowledge of cams (which isn't much) that's completely backwards.. and all it will do is decrease duration and lift. Unless cams in OHC engines are backwards from pushrod engines.. and the lobes are what make the valves close, not open. someone want to enlignten me here? I can understand most technical jibberish.
Now, after looking at this site, you should be able to understand how the regrinds work. When you remove material on the bottom of the lobe the closed position is different on the cam and this will change the whole cam specs. At this point you need the shims to make up the difference of the missing material and you still have the different specs from the regrind. The one thing is, you will never be able to make a regrind cam as good as a full billet cam. There will always be better performance from billets but regrinds will ALWAYS be a LOT cheaper.
#21822, "RE: If you know 420a heads, please read this and help me!!!! Fast420a also read" In response to Reply # 7
that explains everything.. If you had said taking the material off of the bottom (non-lobe) part of the cam it woulda all made sense to me.. hehe. cause I do understand that if you do that and reshim the rockers or whatever then it will make it seem like the cam has a larger/better profile and what not. thanks very much for the clarification.
btw. didn't need to look at the site, your explination was more then enough.
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Intake and exhaust 1.175 inches. So here's what you do. Mic the shortest section on your regrinds, calculate the difference from stock, and divide that difference by 2. It's basically the change in cam radius during closed valve angle. That will give you the amount of shim to mimick the original lash seat height. It should give a good starting point anyway.
