Increasing compression in a (1)F engine.

[MtnClimber]

Hey guys...
I read some info on the (1)F engine and found out that this engine runs with, in my opinion, a very low compression ratio (6.8:1). Is there a piston kit to raise the compression for the F? Perhaps Chevy pistons? I would like 9.5-10:1. I know that the raise in compression would require more fuel, possibly a higher octane, and different timing.
I only ask because key words like compression, raise compression, higher compression, compression pistons etc aren't coming up with what I'm looking for in search.

 

[FF LC FREAK]

My F engine FSM states that the compression is 7.8:1. Still not extremely high, but higher than what you quoted. You have to remember that these rigs were sold around the world and fuel supplies weren't always as predictable and stable as it was here in the US. The low compression allowed use of much lower octane fuel.

Sorry, I'm not much help on your question of different pistons, though. I do believe the 2F engines had higher compression. Is there a reason you want the higher compression with the F engine? Why not switch to a 2F?

 

[MtnClimber]

Availability I guess. I read the 6.8 off of Wikipedia so it's not guaranteed to be correct. Not a whole lot of used parts available in this state and I'm kinda keeping the budget low on this rig. I'm sure I could just bump up the compression by milling the head and having a custom head gasket made. No biggie really. I'm just looking for a little more power. It drives fine, but really looses a lot of grunt going up hills.

 

[IDave]

Read about decking the head.

 

[Ziffdaddy]

Yeah, I second shaving the head. I did that when I pulled my head and it made a noticsbke difference....along with a vac adv dist. and a very thorough rebuild of the carb. Wish I'd shaved more...I think I had .050 taken off? .030 was just to level it. Make sure your machine guy knows if it's been milled before....good luck!

 

[maximum destruction]

Read about decking the head.

x2 decking the head or milling the block to 0 deck height will raise it. just be sure to check piston to valve clearance upon reassembly. go ahead & laugh, but i use children's playdoh. bolt the head on with a few bolts & spin it slowly. take head back off & measure the flattened area in the playdoh.

 

[MtnClimber]

go ahead & laugh, but i use children's playdoh. bolt the head on with a few bolts & spin it slowly. take head back off & measure the flattened area in the playdoh.

Actually, I do the same thing. Old trick my dad taught me.

 

[maximum destruction]

it's the only putty i've found that will squeeze completely out if u're a little on the tight side. i'm not sure of the equation for a cruiser 6 but for a sbc, every 0.15 u shaved is supposed to take out 1 cc from the combustion chamber.

 

[76FJ40]

IIRC, Mark Watley says you can share 0.10" from the head. I took 0.080" off the head of my 2F and even my wife could tell the difference.

 

[splitshot]

Locate a 2F, and spend the funds on it. Just my .02..

 

[maximum destruction]

if he shaves the head, he needs to deck the block as well. engine temp. cycling is what causes the distrtion. if the head is out, the block has to be out as well or it would spit out the head gasket. it's kinda futile to put a machined head on an out of square block surface. although a quick couple passes with a flat file over the top of the block will tell. there should be more than a few spots not touched by the file.

 

[Ziffdaddy]

....and my block wasn't out, and it did spit out the head gasket.....besides, my machinist said the head will warp much easier than the block on these things.

Edit: the head gasket blew between cylinders, which was why I had the head off in the first place. Thank God the block wasn't damaged...