Mike Gayner

Howdy folks, just wondering a couple of things about my dissasembled motor. First, are these the standard pistons, or aftermarket? I can't find any numbers on them so it looks like I have a standard bore block :D




I want to re-use these pistons so does anyone have any tips to get all the carbon off the top of them? I was thinking of just soaking them in petrol for a couple of days.

Next question, these are open chamber heads, right?



I'm a bit miffed about having OC heads because I was hoping for decent compression but I'm on a budget so I'll have to stick with them.

I was also hoping not to have to grind the crank but it's pretty badly scratched up, have a look...

Tones Teo

Hey Mike, whats with the picture of the Chevy on the wall?

Nod

They look like standard pistons and OC heads. If this is a 351 those heads are probably a good choice for a standard rebuild as you wont have any compression problems.
The crank doesnt look too bad from what I can see. Try linishing it with a bit of fine sand paper to remove or smooth over any minor burs or ridges, and it might come up fine.
You can clean the piston tops with oven cleaner and a bit of fine steel wool or a Brillo pad, But dont scour the sides of the piston with these.

Mike Gayner

Haha, it may be a chevy but it's no slug!

Nod - It's a 302 - what sort of compression can I expect with this? thanks for the advice, will have a go at cleaning up the pistons and crank this week. I might take the crank to the local machine shop and see wht they think, because when I run a finger nail across the journals there are noticable high and low spots.

mach1mike

Mike, are you sure its a 302? If its a 302 there will be "302" cast into one of the crank counter weights, the 302 has a 3 inch stroke against the 351's 3.5 inch stroke. Those open chamber heads will make the engine pretty lame as the way the 302 offset its shorter crank throw was to reduce the head chamber size to build the compression back up.

Mike

Mike Gayner

Yup it's definately a 302. Maybe I should try to pick up some closed chamber heads cheap on trademe. Bugger, always more money to spend.

Mr FORD

You should get the bores and the pistons measured properly and also get the ring lands check , some times they are not worth re-ringing , to much wear in the bore , pistons srunk on the skirts , ring lands flogged out , the 302 has a longer rod to get the compression back because of the shorter stroke , what model 302 is it because the early 302s had closed chamber heads or is it a XC onwards pollution engine .

Mike Gayner

I honestly don't know what model 302 it is, but I'm 99% sure my falcon was originally a 6. I guess it's a polution engine because of the OC heads. Anyone know how I can find out? I will need to find out eventually anyway because I need a new dizzy and I'm told the early blocks have a different diameter bushing to the late blocks.

xdclevo

If it has a points dizzy, it is most likely the old type block. Also, a 302 never came out with OC heads, so these have been fitted later, but who knows why! If standard OC heads/block, it would have about 7.8:1 comp.
Maybe if you can source a 351 crank/rods cheap, you could kill 2 birds with one stone

__________________
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408 Cube Cleveland.

Mike Gayner

Arg I really didn't want to spend any more money than necessary on this! Well I suppose you're right, I'm better off spending the cash on the crank and rods than buying heads to suit the 302. Arg more months watching my poor XA rot on the driveway waiting for an engine :(