Valve-Piston distance

-
B

bjopau

Member
Joined
Oct 17, 2009
Messages
17
Reaction score
0
Just got my SB heads back from the shop.
new valves all over. increased to 2.02 intake valves.
planed 1mm (about 0.40")
my camshaft:
Summit Racing Part Number CCA-CL20-225-4

Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,300-6,500
Intake Duration at 050 inch Lift 240
Exhaust Duration at 050 inch Lift 246
Duration at 050 inch Lift 240 int./246 exh.
Advertised Intake Duration 284
Advertised Exhaust Duration 296
Advertised Duration 284 int./296 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.507 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.510 in.
Valve Lift with Factory Rocker Arm Ratio 0.507 int./0.510 exh. lift
Lobe Separation (degrees) 110

I have mopar performace dish pistons. Deck hight about 3mm, dish about
1,2mm.
You can`t see it at the pictures, but the intake valve is actually a little bit closer to the piston than the planed surfaces.

Anyone who has excperience with similar setups?
Will I have a problem with too small distance between valves and pistons?

Bilde0168.jpg


Bilde0170.jpg
 
These are things you will just have to check upon assembly.
Put a piece of clay on the piston and see what happens.

that's not a very big lift at all on the grand scale, so you may very well be fine. You won't know until you check it.
 
and now much duration either...

just remember it is not the max lift that causes problem..

but during the overlap period of the camshaft where the exhaust is closing and the intake is opening that the Valve to piston clearance is critial...

that is why advancing or retaring a cam with out checking clearance can bite you in the butt...
 
70aarcuda said:
and now much duration either...

just remember it is not the max lift that causes problem..

but during the overlap period of the camshaft where the exhaust is closing and the intake is opening that the Valve to piston clearance is critial...

that is why advancing or retaring a cam with out checking clearance can bite you in the butt...
Click to expand...

I saw a kid on another message board that I know destroy a really nice brand new engine by not checking this and/or not using a degree wheel. I felt so bad for him because he's one of those kids that never has any money...there he was all proud of his new motor with all of the good parts he saved up for....gone.

So good point! BJ, if you need help with any of this, please post pictures and questions man, by all means.
 
I'm not familure with how the degree wheel works... can someone explain? I know that the crankshaft lines up with the dot on the camshaft gear and all that but does this allow you to change this in some way or just tell you when your valves start to open with a different cam?
 
POS Dakota said:
I saw a kid on another message board that I know destroy a really nice brand new engine by not checking this and/or not using a degree wheel. I felt so bad for him because he's one of those kids that never has any money...there he was all proud of his new motor with all of the good parts he saved up for....gone.

So good point! BJ, if you need help with any of this, please post pictures and questions man, by all means.
Click to expand...

Thanks for all good answers.
The Engine had a prette new camshaft and timing gears/chain when I bought it, so I will just replace the camshaft without changing the timing. will just remove the gears and chain carefully, and put it back on again.
But I will definately try to mount it together and turn it by hand to see if the valves touches the pistons.
I will also have to check the pushrod length. I am changing the rockerarms to sealed power SLP-R-861 and SLP-R-862. they look like some of the ones I had. (It was two different types before)
And I will definately ask before I do something stupid, thanks
 
POS Dakota said:
hehe yeah lol. Like I said, I saw what happened after the fact.
And this is on a board where there isnt much useful advice.
Just a bunch of peanut gallery a-holes with yards full of broken cars.
Click to expand...


Prolly was realoldspower.com ... bunch of jak offs.
 
You must log in or register to reply here.
-

Back
Top