what to do w/ the engine at the rebuilder

[lemurfart]

im taknig my 340 to a shop this weekend to get a full run through, apparently the reason my engine wasent running was because a rod had welded itself to the crankshaft. fun....

i was just trying to get some good ideas of what to tell this guy to do.

i want forged pistons new lifter and vavles and such
of course rods and crankshaft, camshaft

i dont know to much about engines, or anything for that matter and wanted to see what you guys think

at some point i want a BDS on this thing and i hope to get the highest HP possible with it still being "somewhat" streetable.  its my 3rd car so i can still have fun

[Chryco Psycho]

Use Speed Pro forged pistons L2316 is close to a stock piston & very strong unless you are really serious about going to a supercharged engine , in that case the pistons will need to be in the 7:1 range & the engine will not make a lot of power until the blower is installed & totally different cams grinds are needed for both applications 
 just get good machine work done amking sure the crank & rods are sized correctly & the block is squared , new rod bolts ETC 

[lemurfart]

alright sweet, so just amek this thing run nice as hell then when i get the blower get a new cam and such and tune it then

sounds like a plan.  thanks

[71383bee]

alright sweet, so just amek this thing run nice as hell then when i get the blower get a new cam and such and tune it then

sounds like a plan.  thanks

I don't think you understand here.  A blower requires very low compression compared to a normally aspirated motor.  If you build that 340 with 7:1 compression you will have to tune the hell out of it to get it to run well.  I think what Chryco is trying to tell you is that you can either build the motor for a blower now, or later.  It's not like a carb swap.

Besides 340's love compression which is part of the reason why they were so potent, a 7:1 compression 340 will be a dog IMO.   

I would specify a minimum of 9.5:1 compression and get a cam in the 230 ish range @ 0.050 with an LD340 intake and a decent mighty demon carb.  Or just use the factory intake and a good TQ because they were pretty darn good from the get go. 

[lemurfart]

ok im in learning mode now

when you ay 9.5:1 that is more compression than 7:1 right?

which means that your engine needs to be stonger to handle the greater pressure, thus the forged pistons and such

i just want more knowledge about this whole thing because as far as im conserned im getting throw through a loop with this whole car thing.    i KNOW i overpaid for my car and im willing to deal with that but i just want thing to get the nicest engine set-up it can with a 340 that i can drive on the street.  then in a small amount of years pull it all out and do the body.  im in college and im freakin out at the moment also because my jeep daily driver is giving a rashen of crap .  either donating or blowing it up and getting a nissan titan is my plan. 

my main problem is i have this feeling in my head that when i get this engine done, its not going to be done right so ill have to do the whoel 3000 dollar thing over again when i get the blower.

i dont know im just having an issue with the whole thing at the moment and everytime i think about it i verge on nervous breakdown. 

:end of rant:

[71383bee]

Well sort of....stronger pistons does not mean lower compression.  Compression is determined by the quench volume in the cylinder.  Bassically you have a choice.  Either build the motor for a blower now with low compression pistons or you build it to run without power adders with high compression pistons. 

Since you are new I would suggest a basic rebuild on your 340 and you can upgrade it as your learn more and aquire more sending flexibility.  A super charged 340 is quite a challenge for even a novice to handle.  You really need to know what you have. 

The 340 is one hell of an engine.  It's nickname is the mini hemi.  With the exception of the hemi's they were the only engine built specifically as a high performance engine. 

That's why there is no such thing as a 2Bbl 340 unless it's got 3 of them!   

I apologize if you posted this earlier but i was wondering what happened with your car?   

[Oldschool]

Lemurrip,
    You are correct in making sure you get what you want BEFORE you begin this endeavor.  IF you want a blower motor, then you need to build it as such, knowing that will run pretty weak until you add the blower later.  The problem is that the engine needs to have low compression in order for you to use the blower "boost".  Low compression combined with boost is what gives your engine the power. The blower "stuffs" more air/fuel in the cylinders than would be inducted in a normally aspirated engine..  If you had high compression AND a blower, your compression would be too high and it would struggle to run on even racing gas. Or you could reduce the blower ratio, but if you must reduce it, then why even have it?  Make sense?
   Bottom line---you can't build a 9 or 10 to 1 compression motor now, and add a blower later.  That won't work very well.  If you want it to perform as soon as you install it, either build a blower motor complete with blower, or a higher compression, normally aspirated motor.  Since you are relatively new to this whole high-po engine thing, I vote for a 10:0 normally aspirated motor.  Open her up and let her breath, and it will run great.  Clean up the ports, cam it, good intake/carb set-up, ignition, and headers will make that 340 a very stout piece indeed.  Just my 0.02        ...Oldschool
   

[MEK-Dangerfield]

Lemurrip,
    You are correct in making sure you get what you want BEFORE you begin this endeavor.  IF you want a blower motor, then you need to build it as such, knowing that will run pretty weak until you add the blower later.  The problem is that the engine needs to have low compression in order for you to use the blower "boost".  Low compression combined with boost is what gives your engine the power. The blower "stuffs" more air/fuel in the cylinders than would be inducted in a normally aspirated engine..  If you had high compression AND a blower, your compression would be too high and it would struggle to run on even racing gas. Or you could reduce the blower ratio, but if you must reduce it, then why even have it?  Make sense?
   Bottom line---you can't build a 9 or 10 to 1 compression motor now, and add a blower later.  That won't work very well.  If you want it to perform as soon as you install it, either build a blower motor complete with blower, or a higher compression, normally aspirated motor.  Since you are relatively new to this whole high-po engine thing, I vote for a 10:0 normally aspirated motor.  Open her up and let her breath, and it will run great.  Clean up the ports, cam it, good intake/carb set-up, ignition, and headers will make that 340 a very stout piece indeed.  Just my 0.02        ...Oldschool
   

     

  I agree totally OS.  Since he is new to this stuff, I think he should forget the blower thing for now. A higher compression 340, with a decent cam and carb. can do wonders. A set of headers, and a decent exhaust system, I think he will be just fine. My 2 pennies worth. 

  Mike

[lemurfart]

you guys have to realize this is the best website ever.  ill have to tool it around in my head for a while but OS's idea sounds nice and then if im really fealing the need for some bling bling and power ill get the blower later down the line

im putting tti header and x pipes and whatever the loudest mufflers that are allowed on the street are.


oh my engines story.  the bastard that had the car before me worked the thing over, put some real money into it.  it has race parts on it, then attached NOS nitrous to it and blew a rod and ended up getting the rod bearing weld to things and such.  yes never pretty, actually the first thing im checking during the rebuild is if the block has any cracks or anything.  if it does i dont know what im going to do

[nivvy]

Or you can just do what im gonna do....run 10 to 1 compression......save up the money and buy a Procharger with the water inection kit and not have to worry about compression..the f3 procharger will take me to 1000 Hp...lol

8 Pack

[70RTdroptop]

I had my 440 motor rebuilt last September, and had the following done to it :
checked engine block and heads for any cracks
bored .030 over
Speed -Pro forged pistons
.444 lift cam
block align-bored and decked
3-angle valve job
dual valve springs
Melling oil pump

Anything that looked questionable was replaced. Might as well do it once, and do it right. If I were you, I'd build a higher compression 340, better cam, etc. as has already been suggested, and have a sweet running engine to enjoy.