can i do fi with my engine

[krzykrl9600]

i have a 96 rs convertible swapped out enigne at 104000 miles with a built one i got off of a guy around here
this is what is done to it:
-stock block bored 40 over
-custom made and blueprinted diamond racing forged pistons with valve reliefs
-sealed power piston rings
-diamond racing forged wrist pins
-512/520 lift comp cams
-comp cams roller lifters
-comp cams valve springs to match cam
-arp rod bolts
- ported and polished upper and lower intake
-mild head porting with 5 angle valve job
-msd coils
-stock lt1 fuel injectors
-ceramic coated pacesetter headers with y pipe and high flo cat
-new oil pump and timing chain
-ngk spark plugs i think he said one degree colder
-8.8mm 300+ race wires
-cryo treates crank/pushrods/connecting rods/pistons
-duralast gold alternator & starter
-fel pro gaskets
i thought he said it was 9.1 compression but i could be wrong is there anyway to tell by looking at all the paperwork for the parts?

so would this engine be good for fi as is or would i have to do some more modifications, any input would be appreciated

thanks
karl p

[grayman]

Re: can i do fi with my engine

looks like a nice score you made with that engine.

the pistons might be a concern, however...
"custom made and blueprinted diamond racing forged pistons with valve reliefs"

I don't think a 512/520 lift cam requires valve reliefs to be ground into the pistons at near stock compression. I would be suprised if they are 9/1 ratio. stock is 9.4. It seems to be built for NA...or just plain built to be sturdy as well.... YOu do need to find out the compression for sure.
What kind of gas did he tell you to use? Premium? Have you tried lower grade fuels vs higher grade fuels? does th engine ping with low grade fuel? You might have 10.5 or even 11/1 ratio pistons in their.

the paperwork should mention info on pistons somewhere....

Has the block been sleeved?

Good luck with the project. It seems like a good powerplant.

are we talking about an LT1 motor or an L36?

[Camaro Dom]

Re: can i do fi with my engine

hey! i'm from troy too! :wavey: welcome to the board!

[Camaro Dom]

Re: can i do fi with my engine

hey... wait a second... are you perchance married to a Melodie?

[slow6]

Re: can i do fi with my engine

"bored 40 over on a v6 with diamond pistons"? sorry, but im Very skeptical
it would be cool though

[97rs4life]

Re: can i do fi with my engine

bored 40 over is too much. 30 over is like the limit for our blocks with water jacketing or whatever it is called

[krzykrl9600]

Re: can i do fi with my engine

he still tells me its bored 40 over???

yes i am engaged to melody.

the enigne is a 3.8l

i don't see any compression nmbers on the sheets, so how would i find out for sure?

he said he used premium and sometimes mixed with race, but i only use premium.

not sure if the block has been sleeved

i thought he had mentioned something abut the valve releifs to lower compression but i could have heard wrong or forgotten, sine i got this engine about a year ago and just got it put in this summer.

thanks again
karl p

[krzykrl9600]

Re: can i do fi with my engine

oh yeah on the diamond custom spec sheet it says bore 3.840 and compressioin height 1.102
thanks

[grayman]

Re: can i do fi with my engine

ok not that I know anything...
I have read many times but never visited a machine shop that knows the L36 that 40 over is too much for the L36.

as far as compression....if he was using premium becuase he had too...(high compression) vs just using premium because he thinks it is better and also that your spec says '1.102' it might mean that those pistons are approximatly 1.1 ratio taller...or 10.5 compression pistons vs 9.4 (stock) compression pistons.
(i cant seem to bring up your reply while I am making mine...) so check the stock bore of the L36 and compare it to that number you quoted. that might show the difference and thus how much 'over' bored the pistons are.

valve reliefs do reduce compression but pretty much only becuase they are small divots ground into the top of the piston to allow for tall valve lift. since it is a divot they do figure into compression ratio...but valve reliefs pretty much go hand in hand with high compression. you don't often see valve reliefs on low compression pistions, in other words.

are you driving this thing? is it pretty darn fast? a lot faster than a stock 3.8? you might just have to settle for a turn key naturaly aspirated ride. :naughty:

[krzykrl9600]

Re: can i do fi with my engine

i called him and he said it is 9.7 to 1 compression.
how is that?

it is faster than it was before, i think, but i also have a failing auto trans and i think the one pice driveshaft balace weight near the tailshaft is hitting the trans mount setup.

[Turbo V6 Camaro]

Re: can i do fi with my engine

i called him and he said it is 9.7 to 1 compression.
how is that?

it is faster than it was before, i think, but i also have a failing auto trans and i think the one pice driveshaft balace weight near the tailshaft is hitting the trans mount setup.

stock is 9.4:1

[grayman]

Re: can i do fi with my engine

stock is 9.4:1

it could be aftermarket head gastkets or he may have had the heads milled slightly. there are a few ways to pick up a bit of compression like '0.3'

if the engine really is 9.7 then you can still boost it. you most likely wont want to go higher than 6 or 7 psi...especialy at first. you could be opening up a whole bunch of problems if you try for substantial boost.

6psi is still 50+ hp to the wheels...you will know it.

[slow6]

Re: can i do fi with my engine

stupid question: its an N/A engine, why couldnt they let it be a high CR engine??

[UDLOSE98]

Re: can i do fi with my engine

6 psi under high compression may be more hp

[Turbo V6 Camaro]

Re: can i do fi with my engine

9.7 is not that much of a change you can do 12psi easy (with fuel tuning upgrade's)

HOW EVER if the motor really is .040 over i would NOT boost it