sand man

here goes .
2008 LY6 motor , bought the following parts :
4" callies compstar crank
6.125 compstar I beams
wiseco 4.030 -20cc pistons

the cam is rather small ,I want a good daily driver with manners

230-234 , .609" /.612" 115+4 LSA LXL lubes

heads are going to be hand ported and 3 angle valve jobed. with stock 69.8 champer and LS9 head gaskets.

will not port the intake or TB for now .

target boost on 91 gas is 14-16 psi and 20+ with methanol/water injection

calculated compression will be right at 9.3-9.4 :1

here are my questions :

what ring gap for top and second .
the Joe Potak book says that the street power adder shold be .020 and for high(race) boost should be .025 ,

is there any down side if I went with .024 or .023
wich is in between the .020-.025

second Q is , will my 36lbs injectors work with this engine while its N/A ?
the cam according to Pat will pull untill 6800-7000rpm
I wont attempt to pull it that high with stock 36lbs , just at 6000rpm would be good for a temporary setup.

third question is .
breaking in the motor.
what oil should I use ? any oil additevs? preferd assembly lubes ? or just use the usual 5w30 oil ?

do these cranks, rotatings need to be grinded for clearnce ?

do you guys recomend me running the King bearings or shoud I buy somthing else like clevite coated ?


last , any method for priming the engine with oil befor starting it for added insurence?

sand man

no one really ?

oakley6575

iTrader: (5)

I'm running 42lb injectors on my NA 408 and the duty cycle is around 80% at 6300rpm. So the 36's might be cutting it close. I ran regular oil with comps break in additive for the first two oil changes. I'm running clevite bearings without any issues. The rotating assembly doesn't need to be clearanced like the old sbc needed to be. Also I primed the motor with the starter. Just turned the motor over a few times until it read pressure. Then cranked it and it has been perfect since. So far I have around 7k miles.

I don't know about the ring gaps. I just gapped mine to whatever wiseco specs said. Not sure about a boosted engine though

1FastBrick

iTrader: (17)

It is the holiday weekend over here so be patient.

For Boost I have would probaly run in the .024 range on the top ring. For The second ring you may want to go slightly more clearance like .028. I have always been told the same information that's posted here... Piston Ring End Gap Recommendations

I think you might need larger injectors for that size of motor even being NA.

I always use assembly lube on finally assembly. For Oil I would run what ever is cheapest. and 5/30 is fine. I usually drain and refill the oil and change the filter after start up and first heat cycle. I do this to insure that there is no contaminates in the engine and also want to make sure that the assembly lube has broken down and is not plugging up the filter. I then run my 500 miles for break in on the fresh oil and repeat.

Bearing brand is more of a preference. The coated ones are supposed to retain the lubricity and reduce friction at high RPM. Be careful with them during mock up and checking clearance's so you don't damage the coating.

As far as the crank clearance goes you will have to mock it up and check with all the parts. You will need to measure all the bearing journals as well to make sure they were ground correctly.

Lastly the sale pre lube tools. It's a pressurised vessel that forces the oil into the oil passages usually from a sensor hole. It's not absolutely needed but is recommend to prevent dry start. Usually assembly lube helps with dry start conditions. Not very many people use them. Most people crank the engine with the injectors un plugged and the plugs out so it will build oil pressure with no load before starting it up. If you do this Un plug the coil packs so they don't arc

I have always wanted to try leaving the oil pressure sensor off and pouring oil in with a funnel to try and pre fill the oil passages on a new motor.

1FastBrick

iTrader: (17)

Boosted engines require additional clearance so that they don't but the rings up and break the piston. The added Heat and cylinder pressures will make them Grow more then an NA engine.

I was also think the 42 or 44 Lbs injectors would be need for an engine that size. Thanks for confirming!

sand man

thanks guys , so I orderd this



its for less than 19$ without shipping

hope its going to help

injector wise , they are temporary , I even can tolerat shifting at 5800 rpms to 5500 rpms

just dont have the money to buy somthing bigger like 50-60lbs

for piston rings , I might just go with what Joseph Potak's book and wiseco recomended

wich is mild PA .050 and the race boost is .065 so Ill be going with .060 wich is

4.030x0.060= 0.02418 , might step it to 0.025
and the second should be
4.030x0.065= 0.026195 ,will do 0.027-0.028

what do you think ?

..

thanks

sand man

BTW any bad effect form having slightly larger ring gaps?

1FastBrick

iTrader: (17)

To answer question Maybe a little blow by but its better safe then sorry.

Your Ring size is in the neighbor hood I would run.

sand man

great great , lower cyl. pressure but safer is alright with me

1FastBrick

iTrader: (17)

I think you will be just fine running on the safe side.