just tore apart a 383

[rt green]

just tore apart a 383. it had high dome pistons. 30 over. part number L2293. looks like an older rebuild. anyone know what these piston are?

[A383Wing]

L2293F are forged & are advertised as 11:1 comp pistons with 88cc heads & composition gasket

did a search and found that quote above

[BSB67]

L2293F are forged & are advertised as 11:1 comp pistons with 88cc heads & composition gasket

did a search and found that quote above

I believe this is correct.  But measure the dome height and get back to us to make sure.

[c00nhunterjoe]

Those are OLD trw forged pistons. If memory serves, they sit about .020 in the hole
Measure to be sure but running them with the std .020 steel gasket was the trick and got you a healthy 12.5:1 on 915s and 11:1 on 906s. They were heavy, but if balanced and with the 509 cam and opens or 557 cam and closed heads, you could run run 93, spin to 8000 and be king of the street. If you dont use them and they are in good shape, im interested.

[rt green]

this is going to be a street car. got any flat tops for trade?  the TRWs are 30 over

[BSB67]

this is going to be a street car. got any flat tops for trade?  the TRWs are 30 over

Again, measure the domes.

I would not be able to answer the question from here, but there is a chance that you could make that piston work.

[c00nhunterjoe]

Indeed, i wouldnt hesitate putting them in a street car. Choose a cam that is appropriate for the MEASURED AND CALCULATED static compression to give you the desired dynamic compression and you can have a nasty street car. 

[rt green]

i'll measure.

[c00nhunterjoe]

I am extremely curious and borderline excited on this build.What was this engine in? Why did you tear it down? Are the pistons still in the block? What cam is in it?

[rt green]

1970 barracuda. 4 speed . just got it. engine not sealed up very well, but not rusty. no piston ridge. cam looks worn. 30 over. didnt have a socket at home to take off the dampner. can feel a little slop in the chain.  tore into it to see what i have.

[c00nhunterjoe]

Measure the piston height before you tear it down further. That will help immensly with choices. Behind a stick, this could be a nasty street car.

[John_Kunkel]

Pin height on the 2293 is 1.195".

[BSB67]

Pin height on the 2293 is 1.195".

That would put it between 0.020" to 0.025" below an uncut deck, as I think someone already mentioned.

[c00nhunterjoe]

I was going by memory, and i had to really think on it for a while... But at least john's number confirms my memory, PHEW! Lol.

They are a good old school piston in my opinion. If you had to buy new, there are plenty better options nowadays, but these are the right price...

[rt green]

scavenged a few of the measuring tools today. should have what i need for tomorrow nite. 

[c00nhunterjoe]

 

[rt green]

only had time last nite to do part of the measuring. life got in the way. side of the head on the lower pad measures a full inch, so they havent been plained. crushed head gasket thickness was .039. i have to pull out the cherry picker to help lift the engine on the stand to get it level to cc the piston in the block. it just got to late to do that. did clean up a piston top and noticed two flat plaining marks on the upper dome. maybe they took alittle of the top. i was suprised to find no piston ridge at all in the cylinder.

[rt green]

12cc domes 020 down piston height. 906 90 cc

[firefighter3931]

12cc domes 020 down piston height. 906 90 cc

I come up with 9.63:1 using a .040 composition head gasket.

Good candidate for a set of 84cc closed chamber aluminum heads....using the same head gasket the static number is a pump gas friendly 10.23:1 


Ron

[rt green]

thanks guys. cam?

[c00nhunterjoe]

Depending on what cam and what heads you wish to run would dictate what static compression i would suggest aiming for. Are you reusing the stock irons or going aluminum? What headers or manifolds? Whats the total goal for the car before you pick anymore parts. "Street car" is VERY vague in todays world. Keeping the 4 speed? Lots of variables to consider here.

[rt green]

worried about quench with 906 heads. street car. but would like some punch. back and forth to work, fun ect. headers. keep the 4 speed. if i could afford a a set of kb400 pistons,[i think thats the number]  or build one of my 440s right now, i would scratch the trw pistons.     

[rt green]

the only cam i have besides a new stock replacement one is an engle k58/60.   

[BSB67]

worried about quench with 906 heads. street car. but would like some punch. back and forth to work, fun ect. headers. keep the 4 speed. if i could afford a a set of kb400 pistons,[i think thats the number]  or build one of my 440s right now, i would scratch the trw pistons.     

The pistons you have now are as good as anything that KB has to offer, IMO.  There is only one reasonable piston for a 383, and it is not offered by KB.  If your number are correct, you have options.  You cannot get quench, but you still have something to work with.  I would suggest that you double or even triple check your work and results, as a couple of cc's will make a difference on a 383.  Once you've done that, and picking the cam you want, you should be able to hit your desired CR with available head gasket choices.

If your numbers are right, use the 0.040" gasket and a cam like the Crower 271. 

[c00nhunterjoe]

  that will make quite the fun ride at 9.5:1.

Another option if it were mine and you are running 3.91s or 4.10s would be up the compression and go with more cam since its a stick car. The steel shim gasket can get you the needed compression on the 383 to run a steeper cam like the crower 282 or equivalent cam in the low 500 lift and 240's @ .050. If you have 3.55s or less, then go with the 1st cam suggested, even with the 4 speed.

***edit**** seeing the post about having the engle cam on hand- that cam should work well in this engine. I would say no less then a 3.55 gear.

[rt green]

 so to tell me that i have something [engle cam] in my part stash that'll work?  man, i'd never thought i'd see the day that'd happen. sure that cam is not to much? FWIW i tore this thing down and it had a nylon upper timing gear. not much wear.  blast from the past.

[rt green]

that will make quite the fun ride at 9.5:1.

Another option if it were mine and you are running 3.91s or 4.10s would be up the compression and go with more cam since its a stick car. The steel shim gasket can get you the needed compression on the 383 to run a steeper cam like the crower 282 or equivalent cam in the low 500 lift and 240's @ .050. If you have 3.55s or less, then go with the 1st cam suggested, even with the 4 speed.

***edit**** seeing the post about having the engle cam on hand- that cam should work well in this engine. I would say no less then a 3.55 gear.

you talking steath heads or 906?

[c00nhunterjoe]

Your 906s. You should sit down and plug all of your figures into a dynamic compression ratio calculator. That is the main problem that comes into play when people overcam an engine. Experiment with cam choices and you will see the effects they have on your dynamic compression and why cam choice vs static compression is so critical. My goal on iron open chamber heads like yours is a dynamic of 8.0 to 8.5:1 to run 93 octane.
  Here is a basic and simple one that will give you the idea. The intake closing should be on your cam card. I dont knkw what it is on the engle cam.
http://www.wallaceracing.com/dynamic-cr.php

[Challenger340]

The L2293 Pistons for the 383 Engines were somewhere around 10 CC's "NET" if memory serves me ? NOT the mentioned 12 CC's !
in other words....
the 18CC Dome was designed to compensate for the .020" Deck Clrc(4.6 CC) and the 4 Cc "trough" valve relief, and STILL provide -10CC Dome Compression increase.

The 12 CC dome volume number was the L2295 offering for the 440 Engines, intended to act like a zero deck Flat-Top in a 440(9.7 to 10.2 static C.R. depending upon open chamber casting volume)
Nonetheless,
the L2293 383 Dome Piston was considerably higher Dome than the L2295 440 piston, and good for over 10:1 static C.R in a 383 with 88 CC heads.

[rt green]

at Challenger340's insistance, i measured dome with a ring compressor. i leveled it, put the piston down .500.  it took 101.5cc of antifreeze. i figured 11 cc dome.   using summit's compression calculator came up with 9.24 to one.

using the Wallace Racing dynamic calculator  i came up with
dynamic 8.10 to 1                                                                   intake opens  8   closes42
static 9.24 to 1                                                                       exhaust opens 52 closes 6
volume pressure index 170
effective stroke 3.04in
dynamic cranking pressure 161.56 psi                               
Engle k 58/60
valve lift       running duration  valve lash        gross cam lift           duration at .050     lobe centers
in 515           276                     hyd                in 343                        230                     110
ex 536          285                     hyd                ex 357                        238

[BSB67]

at Challenger340's insistance, i measured dome with a ring compressor. i leveled it, put the piston down .500.  it took 101.5cc of antifreeze. i figured 11 cc dome.   using summit's compression calculator came up with 9.24 to one.

using the Wallace Racing dynamic calculator  i came up with
dynamic 8.10 to 1                                                                   intake opens  8   closes42
static 9.24 to 1                                                                       exhaust opens 52 closes 6
volume pressure index 170
effective stroke 3.04in
dynamic cranking pressure 161.56 psi                               
Engle k 58/60
valve lift       running duration  valve lash        gross cam lift           duration at .050     lobe centers
in 515           276                     hyd                in 343                        230                     110
ex 536          285                     hyd                ex 357                        238

Hmmm.

How did you measure the 0.050" down, and how did you measure the volume.. Precision matters.

[rt green]

im sorry, it  was .500 down. old style band type ring compressor with piston and rod in vise.  took a hunk of plastic and measured .500 long and cut. was a bitch to get level. did the proper grease seal on rings and plexi glass.  saw no leakage past rings. came up with 101.5cc. 4.80 x .50=118   118[rounded off]  - 101.5 =16.5.   hmmmm. maybe i should ck my math.   i'm trying

[rt green]

looks like .075 head gaskets, or take 5cc off of domes

[c00nhunterjoe]

I checked my old notes. I had measured the 2293s at 1.911 compression distance. In a stock 383 block that should set them about .020 in the hole. The dome and valve relief measurements i have near what challaneger340 posted earlier. That said, based on your 90cc head measurement, i reccomend Running a blue felpro gasket at .041 netting a decent quench distance even though the open chamber lacks it, and a cam with 74-78° intake closing (think purple 509 size). Will run on 93 and be a rocket with the 4 speed and 3.91s.

[rt green]

thank you. i thought they quit making the 509.

[c00nhunterjoe]

They still make it, and lots of others with similar grinds. To use those pistons and pump gas the ivc is critcal and a bigger cam is the key to get the dynamic compression to pump gas levels.

[rt green]

i think maybe you should own these pistons. pm me if interested

[BSB67]

If you told us what your goal and budget is, I've forgotten.  If you like working on your car and if you don't mind a possible partial redo, you are in a pretty good place for achieving some really good performance, but with some risk of having to get back into it.  I get it though, everyone is different.  Today, folks don't seem to mind spending 10 hr/week talking about their cars and motors and performance, but the thought of actually working on the car for 10 hours (i.e. cam or head swap) is distasteful.

If your budget already allows for new pistons, the budget for new heads will not be more than new pistons, all said and done.  So consider this.  Slightly modify the piston dome on the spark plug side to pull that corner back away from the plug/head.  Consult someone you trust to show/tell you how to do this.  It will do two things, 1) reduce slightly the dome volume, and 2) provide clearance if you go to an an aluminum head.  Put a 0.050" to 0.055" head gasket on, and use a medium sized cam with a wider LSA.  The cost to do this is nothing.

So you put it back together, and it pings.  If it is not too bad there are about a half dozen items you can do to help that, especially in a stick car.  If these don't work, buy the 88 cc Eddy heads and put them on.  This will solve that problem.  

Worst case, you will spend no more on the motor (heads verses pistons), and it will probably run a lot stronger.  

[rt green]

my plans for this car is just street cruise with a little punch. drive to work, enjoy the car. i'm not out to murder imports or anything, but would like to have some fun. i took this thing apart and found the high tops. everything else bearings, ring ridge, rockers, pushrods ect, look Very nice shape, and the inside is spotless. i just got the car, so i'm still jacked about getting it going. my budget right now is lower that anyone elses that has even clicked on this site, but i have to have a plan.  last time i didnt have a plan and it just snowballed. i was buying stuff, changing my mind, buying other stuff, no theres something better, buying more stuff ect.      next thing i know, its 10 yrs later, and still looking at a car that isnt together.  i'm just trying to work with what i have. if i cant, i'll have to sit back and save cash. i do have a stock MP replacement cam brand new, but i thought those pistons would be too much for that.   

[BSB67]

Okay.  Maybe a bigger picture question.  Was the car running when you bought it, and if not, besides getting the motor together, what needs to be done to get the car driving?

[rt green]

it needs everything. its blown apart. why did i start on the engine you ask? i tore into it to see what i had. everything is bagged and tagged.  no, did not run when i got it. but i figured the engine had to be done up anyways. then i could plan rear gears, exhaust and everything else.

[BSB67]

If you want to get this thing on the road and money is tight, maybe start assembling the rest of the car first.  Who know what $$$ black hole you could stumble into.  This kind of a situation (car apart) can nickel and dime you to death.

Put the motor aside, but keep thinking about what you want in the car, and when you get close to the point to where your ready for the motor, then you'll know what you want (at that time) and a sense of the $$ you have available.

Almost every time a guy starts with the motor first, if considerable time passes, it is not the motor he wants when it is time to put it into the car.   

[rt green]

i think i'll take that advice. thanks to all of you who were trying to help.

[c00nhunterjoe]

Thats really good advice! I will add, build your car on paper. Almost like writing a report. Start with an outline, title- goal, then each category, engine, suspension, brakes. Then list all the parts you think you want to use. Now you can look at the whole picture and see what will work together or not, then adjust your goal or parts without wasting money.

[rt green]

thanks to all who were trying to help me with my 383. before i  slid it under the bench, i put the head back on with the old gasket. got the spark plug hole straight up and level. [top dead center with a dial indicator, little vasoline to seal before]   cc'd it. 73cc's.    =11.9 to one   FWIW     thanks again,   bruce   

[c00nhunterjoe]

Slap a monster cam in it and a set of gears and have a nasty old school street/strip car. Excellent score. I am jealous.