Alright i found some pistons while looking around on ebay. I was wondering if i would be able to use them in an lt1. http://cgi.ebay.com/ebaymotors/Small...item4a9efdfd33 Isn't there a formula to figure out if they will fit the deck height?

EDIT: Also is there a certain compression distance have to use or is it based on it the deck needs work?

I will be building a .030 over 355 with a 6.0" rod looking for about 11.5 cr. going to probably end up with le2 setup so it will use 54cc heads. Also if the deck doesn't have to be messed with and using the setup mentioned, with a stock style thickness headgasket what cc piston would i need for that cr?

 

The piston with the x is scaring bidders. The "x" may be designating the fact that a machinist lightened one in balancing the engine. Rod length will not be a problem since the seller states they are for a 3.48" stroke which stock LT1's have. You can use your stock rods which are strong from the factory. The pistons are forged and light weight= two good things.
The piston tops are a-semetric with only two valve reliefs on top the vs. four on stock engine. This will raise the compression a little more like the LT4. With a 4.030 bore raising it also, your finished compression ratio with a thin head gasket will be around 11/1. The scarey part is the expense of correcting an engine after it proves flawed. Most likely these will work, but why are they for sale?

 

are you high? for one lt4's still have 4 valve reliefs. two you cant use the stock rods and crank to get 11:1. it clearly states you need a 6 inch rod on a 3.48 or a 3.5 crank. (3.48/2)+6+1.25= 8.99 inches. (3.5/2)+6+1.25= 9 inches

with that said you would want your block decked and i would probably pass on these because after its all said and done you are probably going to be into them the cost of new pistons

 

You are aware that the stock crank is 3.48" stroke, right?

 

If i were you id go to summit racing online and pick a set of pistons from them especially if your unsure because each item you buy on summit will tell you what its compatible with and what else to buy with it and all kinds of other information with it. And yes the stock crank is 3.48 so your really have to be precise on what pistons and connecting rod assemblies you get so that you know exactly where you are. You can however stay with the 3.48 crank and stock pistons and still bump up compression a little with different kinds of pistons.

 

Thats what i wanted to know. lol. i was doing some research on them and came across some post where people didn't think they would work because of the compression height. I couldn't remember the formula red94chicken used. Thanks guys, i am probably going to use new pistons because all this math hurts my brain, I can go to summit and select exactly what i need. lol

 

Alright found a ross racing piston on summit, part number 90003. When plugged into the calculator on eaglerod.com I get

Deck height- 9.025
Bore - 4.03
Stroke- 3.48
Rod length- 6.0
Chamber volume- 54cc
Gasket Thickness- .04 (used this as just a general size)
Piston Dome- +4.0cc
Pin Height- 1.245 (this would be compression distance right?)

Which gave me:
Deck Clearance- 0.04
Compression Ratio- 11.91:1
Engine size- 355.1
Rod Ratio- 1.72:
Max Rod angle- 16.86deg

So this wouldn't be a problem unless the deck had to be milled down for some reason right? if i wanted a little less cr i could use a thicker gasket?

 

yes smart guy.. read his post.. he states you can use the stock rods which is wrong. reading comprehension is your friend

 

No need for the attitude chief. I was talking specifically to you. From your first post, you said "you cant use the stock rods and crank to get 11:1. it clearly states you need a 6 inch rod on a 3.48 or a 3.5 crank." Besides that being a completely vague statement, to me, that sounds like you don't know what the stroke of a stock crank is.

If you meant otherwise, writing comprehension is your friend.

 

no you are right.. i hopped into this thread with no idea wtf i am talking about. nor the stroke of an lt1.. you caught me. no one here has the brain power and wisdom that you possess. oh mighty lt1 know it all.

 

I'm trying to clarify some things here for anyone else who might come across this thread...not trying to start a pissing match.

You said "you cant use the stock rods and crank to get 11:1. it clearly states you need a 6 inch rod on a 3.48 or a 3.5 crank."

Which if reworded reads, "You need a 6" rod with a 3.48" stroke crank, so you can't use the stock rods and crank." Which isn't true.

People come to the forums looking for advice and information. If it's wrong, other members sometimes feel obligated to correct. If you want to get all fussy instead of just admitting you had your facts wrong, then that's your prerogative.

 

its not wrong.. i was saying that in regards to the the pistons he linked in the first post.. [EDIT]. READ THE ENTIRE POST AND YOU WILL SEE WHERE I WAS GOING. hence the forumlas that relate to the pistons in the link.. add something useful to the goddamn thread.

 

amazing that you got what i was saying but someone who i wasn't giving info to can't. with those pistons a stock crank and rods you wouldn't get you even close to 11-11.5:1. with those pistons, a 6 inch rod and a stock crank it would be in the 12:1 area depending on gasket and head chamber volume

 

OK... its getting out of hand. Knock it off.

Do not override the language filter.

Last warning.