Im a little new....head/piston ?

TylerTx13 · #1 (**permalink**) 07-21-2010, 08:38 PM

New to th site, but i have experience in engine building, just not this extensive. ive got a 351w, .060 over, slowly buying parts to build th engine, have some alum heads with 2.02 intakes, not trick flows, and a .500+ lift roller cam, havent bought pistons, keepin stock stroke. whats about th smallest piston dish i can go to keep clearance good for a weekend hotrod? (me n th shade tree dad dont have many special tools, just alot of common sense) any help is much appreciated, as 5k is alot to spend just to screw up on start up.

Z-linkCobra · #2 (**permalink**) 07-22-2010, 08:56 AM

You need to know how big the combustion chambers are. If they are big chambered heads and you havent decked the block (cutting the surface where the head bolts to the block) then you can probably run flat tops. Also need to know how far in the hole the pistions are. If the pistons are down in the hole 20 thou and you have big chambered heads you can probably run a little pop up piston with no clearance issues at all.

Hope that helped.

Gene

Three Peaks · #3 (**permalink**) 07-22-2010, 10:52 AM

Talk to Mike Forte, I'm sure he can help you out. He is a forum vendor, so try to throw some business his way when helps you out. His service is second to none and he is extremely knowledgable about anything engine related.

www.fortesparts.com

blykins · #4 (**permalink**) 07-22-2010, 11:09 AM

Tyler,

Exactly what heads are they?

Give me a call....502.759.1431. I'll help you through choosing the correct one.

TylerTx13 · #5 (**permalink**) 07-22-2010, 11:53 AM

Their 60cc chambers, I'm going to have to deck the block anyways to get it true, right now I have a head gasket leak with fresh service cast heads, and the pistons will only be in the hole 10-15 thousandths after decking hopefully. Ill definitely hit up the last 2 posts after work. Thanks yall

blykins · #6 (**permalink**) 07-22-2010, 11:59 AM

With a 60cc chamber, you'll need a good-sized dish to be in the correct compression ratio range with pump gas.

With around a 16cc dish and the pistons about .010" in the hole, you'll be at around 9.5:1 SCR. With a .040" gasket and the pistons .010" in the hole, you'll have a .050" quench distance. That should be just fine, but if you're already having the block decked, you can have them square deck the block a little more and get the pistons optimally closer to zero deck.

I can offer some Keith Black hypereutectic pistons that would work great for a mild street engine like this, or for just a little more, Probe's FPS forged would be a nice piston that would allow some expansion later on if you choose.

TylerTx13 · #7 (**permalink**) 07-22-2010, 06:48 PM

i cant recall what size dish my current pistons are, i think whatever stock is. ive read and heard with large valves that are not twisted wedge design clearance is a problem with anything close to flat. is 16cc just valve reliefs or a full dish? the kieth blacks sound good, as i dont really plan on goin turbo/sc or nos at all. im bit old school, all motor, and seein as th parts list i have is long, its gunna be bout a year before i have it complete, if not longer.

btw th heads i beleive are pro comp, came from a head shop in WV, they did a nice job, but figure since their not high dollar ill have my machinist check th surface while he has th block n crank

puppster · #8 (**permalink**) 07-22-2010, 07:11 PM

I would be afraid of the block being bored to .060, only because I have heard stories of heating problems when going over .030
I guess if they sell pistons that large, then they are being used somewhere. Perhaps a knowlegable person can speak up on that subject. It's something I'd like to know more about since my 289 has been bored to .030 already.

blykins · #9 (**permalink**) 07-22-2010, 07:38 PM

The 16cc pistons are full dish. You shouldn't have any issues with a .500" lift cam. Of course, always check piston/valve clearance.

As for boring blocks, it's better to sonic test before boring to see how far they'll go. I wouldn't take a 289 or 302 to .060", but I've had some 351W's that went to .060" safely.

TylerTx13 · #10 (**permalink**) 07-22-2010, 08:19 PM

just read my cam card, .513 lift int and exh both. dish will work for me, i was looking to get 9 or 9.5:1 CR so it would be great. and this block has been bored .060 since i was 13, im currently almost 22, and with the stock radiator so long as it stays above 40mph the temp stays ok (210). but i plan on getting a bigger rad with this build anyways. the 351w is pretty well known for being fairly stout compared to the smaller blocks, they make great boss/clevor/427w builds. but going more than .060 even i wouldnt suggest.

Caprimaniac · #11 (**permalink**) 07-30-2010, 04:43 PM

Have no experience with 351- blocks, but I'm planning a V6 build that will need to be bored 7mm (0.27") diametrical and might have to involve the sleeves...

Brent or someone; If I invest in one of those hand- held sonic testers- will it be useful in a way or another, or is more "professional" equipment needed?

What kind of data will such a tester give? Can thickness be read? Density?

(I'm sorry, none of the books on my shelf says something about this, there's just a photo of the handheld unit....)

Basically, I'm wondering if such an instrument can tell me if it's safe to bore the block this amount. (Or do I have to test & see. My mate did on his V6 and it ended up in disaster; of course. That was a German V6 bored to 3 litres (alà Weslake, if you happen to know), whereas this one is the English V6 going to 3,4 or 3,5 litres (alà Cosworth GAA,...... if you happen to know!)).

Run

blykins · #12 (**permalink**) 07-30-2010, 07:15 PM

The hand-held sonic testers will work fine, but if you're going to try that, I would suggest trying it on some known thicknesses. Another thing that tends to throw results off is that cylinder walls are curved and most of the sonic tester transducers are flat. They really need to be shaped so that they sit flush up against the cylinder wall.

When you test, take a reading all around the wall, but concentrate on the thrust side of the cylinder where most of the load is under the power stroke.