camo31_10.50

ok..so i might be able to get my new attarco head shaved a little...i was thinking 1 or 1 1/2 thousandths of an inch..MAYBE 2...how much performance increase would i be seeing???..is it worth the $60 or so to get it done???...is it gonna give be worse gas mileage..thanks for the info!

rusche

If you mill the head you're gonna want LCs adjustable cam gear, your cam timing will be off.

camo31_10.50

really???..the guy at the shop never said anything about that...hmm...i've never heard of anybody having to buy anything extra after they milled their head...but it does sounds correct..lol

abecedarian

decrease the distance between the camshaft and the crankshaft, and the cam timing will become 'retarded' because the slack in the chain has to go somewhere, right?. simple geometry will help you figure that out.
No one tells you that because retarding the cam will shift your power-band higher in the RPM's.

JonnyBoy

Hmm...my experience messing with old Ford v8's is that retarded timing is good for low end torque, advancing timing is for higher end horsepower. Is it somehow opposite for Toy engines?

camo31_10.50

i guess there is no way around my truck being such a dog around town is there..lol....i need more low end grunt..and i also need more high end power also..like for the interstate..i have a top speed of about 70mph..and thats REALLY pushin it..well..actually..it'll be more with the new head..because my 3rd cylinder was DEAD..exhaust valve was NEVER opening..lol..i thought shaving the head a little bit would give it a little bit more power all across the RPM range..guess i'll check out a adjustable timing gear or whatever..lol..then decide.

even with the price of the milling.. and the price of the new gear..would it be worth it..would the power gain be worth it..

what kind of actual numbers would i be looking at...cylinder PSI was already at about 180 or so...and i think if i shaved it..it would be pushin somewhere around 200 with 1 1/2 thousandths..and maybe around 210 or 215 with 2 thousandths..should be a pretty nice gain right?

abecedarian

my bad.
I mis-spoke. retarding the cam causes those events to happen 'later' which to a certain point, will boost low rpm performance.

I was wrong, and have been corrected.
(I blame the bottle of rum on my right hand side for the fault. )

rusche

I think you'd notice a gain.
I run about 190 psi in mine, but I got a new cam, bigger valves, port matched the head, LC header, and a number of other goodies all at once...

jason191918

Calculate the difference in compression ratio and then use that to calculate the new efficiencies.

Matt16

Or you could gear it. Guaranteed results, boosts economy, no reliability issues.

scuba

I know where your sitting !!!

a4runnerfreak

Take another vic, Scuba......

JonnyBoy

If your machinist is good with ohc engines, ask him if it'll really be a big enough difference to need an adjustable cam gear. Not to totally dispute abe, but when I got a custom cam for my 390 in my Ford, I could retard the cam by 2 or 4 degrees, iirc, and that was a preset number in the cam sprocket. I could also advance 2 or 4, but that's beside the point. The cam could be set 4 degrees off where Ford designed it to be for torque or hp, and it wasn't detrimental, aka piston meeting valves. That's anouther thing to think about, is this an interference engine?
If this isn't something that would make valves meet pistons, then I think it would help with both low end and high end. Cam retarded by a degree, don't think it'd be much more, and higher compression and efficiency at higher rpm's...ask your machinist.

Matt16

I think your engine would have ceased to run if the valve timing were so far off as to put the valves in the way of the pistons.

abecedarian

22re's are interference engines.
the stock cam gear offers no provision for adjusting the cam timing, hence the need for an adjustable gear. also it's been noted elsewhere on other fora that the 22re produces noticibly more power with the cam advanced about 3 degrees over stock.

newbie93pickup

in my experience with timing advances is that it dont really give you bigger numbers par say what it does it triggers ignition sooner so that you get a more complete burn during the power stroke which in turn makes the high RPM power available in the lower RPMs. i found this out by advancing the timing on my bike 5*. brought the power out in the lower end of of the RPM range. still peaked at 11k but instead of being a steady climb from 0 to 11 like a slope on a hill it brought the curve out more so the power rose sharply in the beggining at about 3k and then was a gentler slope on its way to 11k.

so i ended up with 55hp at 4500 rpms instead of 30 at 4500 and then it climbed more gently on its way up to 78 at 11k great for wheelies

oh yeah it also caused my bike to over heat in stop and go traffic because the engine was burning fuel more completely which made it hotter.

JonnyBoy

There's also a difference in ignition timing and cam timing. Sounds like Abe has looked into this, go with his advice Camo. Btw Matt, yeah the engine would cease to run, but I meant upon reassembly after the shave job. It'd suck to have it all together thinking,"what's the worst that could happen?" then try to fire it and have a valve strike a piston.

camo31_10.50

ok..so what have you guys found to be the "magic" number on setting the timing...iirc..mines advanced like 8*...i think...cant remember...so what have yall found to be the best..and if i was to retard it a little..like say..2*-4* i'd get better low end hp/tq...and advancing the timing..shifts the power band high in the RPM range...correct me if im wrong..lol..dont think i'll shave the head..(dad wont let me..)..but i am throwin a header on it..