Cams doubt

[Jan Pedersen]

T_AE86 Wrote:Thanks, i'm learning many things, two options are nice, in general i see it:

16v:

? With a "custom 16v", one of my fears is the reliability (i don't want 200hp) i think about 150 would be good...i don't know if the engine will break in 20.000km.

+ my stock?: I have in the garage one bigport 7 rib and one bigport 3 rib, as I have learned here i would take the 3 rib

+ i don't have to homologate this engine customize

20v

+ Will be a stock engine, it give me more trust with reliability

- I don't have parts of 20 in my garage

- I'll have to homologate this engine


Other option?? ....Is so difficult to made an 7AGE?? (i didn't think it)
I think is not so easy like "mount one stock 4a head in a stock 7afe block" and runs a lot...to make it runs must do more than cams (usable at med rpm too) and HC pistons??

Sorry for this headache mates!!

I would build a hybrid with 7 rib block with small port head and early internals from the 3 rib block. Throw in the large port cams and you will be close to 140 hp. This would be bullit proof and have a nice response. Even better if you lighten the flywheel You should check out Beans and Dans builds!

Next step: Head work, raised CR, cams, ECU, Exhaust...

[T_AE86]

It turns to 16v I usually observe other's projects to learn something

I always thought, all pieces in a customized engine should have a harmony and not all pieces can be "mixed". For example, X pistons with Y cams and Z flywheel could be a "bad working engine"...but with other combinations could be a powerful engine (i don't know if i'm explained)...this is true??

if I have to improvise an 16 now:

I'll take my 3 rib (oil consumed) furbished
high comp forged pistons ??
furbished and polished head with larger valves and springs (worked)
Cams and pulleys (with power midle rpm, not only in hight rpm)
Light flywheel ??
ECU

should i change something?....and i don't know what of those parts are better to get a powerful and usable engine.

[Bean]

T_AE86 Wrote:It turns to 16v I usually observe other's projects to learn something

I always thought, all pieces in a customized engine should have a harmony and not all pieces can be "mixed". For example, X pistons with Y cams and Z flywheel could be a "bad working engine"...but with other combinations could be a powerful engine (i don't know if i'm explained)...this is true??

if I have to improvise an 16 now:

I'll take my 3 rib (oil consumed) furbished
high comp forged pistons ??
furbished and polished head with larger valves and springs (worked)
Cams and pulleys (with power midle rpm, not only in hight rpm)
Light flywheel ??
ECU

should i change something?....and i don't know what of those parts are better to get a powerful and usable engine.

change yes: skip the bigger valves - they aren't necessary until very close to 200hp and will loose torque below that power figure.
before you decide on pistons you need to decide on cams as they are interlinked. For your goals you most probably can get away with the OEM 10:1 pistons and a slightly thinner headgasket.

do both your block have internals? if yes measure them and compare the results with the manual to see if they are still in spec.

mixing parts in the 4AGE world works very well when done right, so you could take the 7rib block and 3rib internals (crank, rods, pistons) as long as all the clearances work out. Best case scenario is new rings, bearings and a light hone. But as said start with checking what you have and see what can be reused and what can't.

[T_AE86]

Bean Bandit Wrote:change yes: skip the bigger valves - they aren't necessary until very close to 200hp and will loose torque below that power figure.
before you decide on pistons you need to decide on cams as they are interlinked. For your goals you most probably can get away with the OEM 10:1 pistons and a slightly thinner headgasket.

do both your block have internals? if yes measure them and compare the results with the manual to see if they are still in spec.

mixing parts in the 4AGE world works very well when done right, so you could take the 7rib block and 3rib internals (crank, rods, pistons) as long as all the clearances work out. Best case scenario is new rings, bearings and a light hone. But as said start with checking what you have and see what can be reused and what can't.

I'm noting it and learning a lot Thank you very much mates
I think will be better including to machine (hone?) the block and take new oversized pistons and i'll forget engine problems for a long time (...and more expensive)...not?
My 3rib was removed because it consumed oil, and my 7rib has a broken bearing...i think your advice is feasible
Like you and Oldsekewltoy said, increases compression with headgasket and machining head (i noted Oldsekewltoy's advice ".8mm TRD gasket, machine head surface .5mm")
I'm "lost" with the cam-pistons conbination... looking not to lose too much power in low rpm (an usable engine)

[Bean]

as said measure first - if the pistons out of the 3rib are in good shape and are within tolerances of the 7rib block - change the internals over with new rings and a hone and it will be as reliable as ever. This is if it can be done within spec as a fresh hone will widen the cylinder diameter.

when we are talking compression there's two things to differentiate.
static compression: the value depending on piston type, headgasket, how much block/head have been skimmed and stroke.
dynamic compression: add the type of cams to the above parameters

basically it boils down to long duration cams need higher static compression than short duration to reach the same dynamic compression because the intake valves close later and the piston is already further up the cylinder.

this is one of the more accurate calculators I found on the net, unfortunately it's in imperial measurements: http://www.projectpontiac.com/ppsite15/c...calculator
a simpler calculator for static compression (can be switched to metric): http://www.csgnetwork.com/compcalc.html

here some more into detail explanations:
http://cochise.uia.net/pkelley2/DynamicCR.html

have fun

[T_AE86]

Thanks ...studing it,

Your post "4AGE block differences" (http://www.aeu86.org/viewtopic/4age-bloc...29/t/13262)also helped me to understand some things

[Bean]

came across this page today with a metric dynamic compression calculator.
http://www.dairally.net/daihard/chas/Com...Stroke.htm
for some reason I can't access it from home but at work it well worked
for reference some intake valve closing figures: bigbort 51°; smallport 44° according to Bill Sherwood. Higher degree figure = less stroke left = wilder cams