I freshen at least 10-12 engines per year for circle track guys on GEN I SBCs
that typically use 1/16" or 1.5 mm rings and I've had great luck with the flex
hone you were considering. A good dozen or so up/down strokes with a drill
set on fast speed and using a thicker motor oil 15/w/40. I wipe that out with
a shop towel, then wipe the bores first with a paper towel soaked in ATF,
then re-wipe them several times with dry paper towels. You'll see each time
having less dirt on the towel. When they're clean and dry then use the Total
Seal quick seat powder which is gray/silver. Dab your finger in it then wipe
the bores in the top 3.5". As others have stated they will turn a greenish hue
if they were properly cleaned. Put the new rings on and install dry. The dry-
film powder will begin seating the rings during assembly. To my understanding
all LS engines consume some oil during normal operation due to the thin/low
tension rings and the PCV style of crankcase ventilation. Obviously you don't
want a smoke machine, but there are so many contributing factors that can
cause an oil burner. Sometimes 2 coarse/rough a hone is used and wears the
moly coating off the sides of the rings. I've seen rings installed upside down
which can smoke badly. Also if the two oil ring gaps aren't staggered can lead
to oil use. Rings can also flutter(reducing seal) a bit more in forged piston
applications where the piston to wall clearances are often .0045"-.0055"
as opposed to .0012"-.002" of a cast or hypereutectic piston. The decision
is yours based on budget but if you change pistons/rods you will need to have
the crank rebalanced.

 

Here is a nickels worth of free advice. If you buy new pistons get a piston for a 3.905 bore and get the block professionally honed with a torque plate. This is assuming the bores will clean up at that bore size. I am a competent machinist who does engine machine work on the side with a friend who has an engine machine shop. We bolted a torque plate on my block and honed it. After checking the bores they were .0002" to .0003" taper and .0001" to .0002" OOR which is well within spec. When we removed the torque plate the bores distorted .002" OOR at the tops and hourglassed .0015" in the middle of the bore. A block honed without a torque plate will live for many miles but you will have a small amount of blowby. Blowby= lower combustion pressure which = lost horsepower. For the best possible do this and you won't regret it. People spend all this money on H/C set-ups and all the others then put them on a half-assed bottom end. The bottom end is the foundation of your motor.

 

Yeah I read in a couple of my LS books that the rings had to be staggered when installed & with the dot facing up, etc or there could be some oil getting by. Ill probably go forged and have the crank,rods,pistons all balanced together. probably cost me out the *** since the local machine shop charges out the ***. they are good & do good work but expensive. Ill give you an example..I didnt have a harmonic balancer puller at the time so I took it to them to pull it off real quick for me.. they said it would cost $75 for them to pull it off for me. I walked off.. It wouldve took them 5 mins max to take it off..

Thats kinda why I want to go forged vs staying stock, got all this money in cnc ported heads, cam, etc & kinda scared to put it on the stock bottom end & worry about it giving up when I rev it to 6500+rpm.. The crank is strong I know that much so itll stay stock. But the pistons & rods Im worried about. My buddy who had the car with this engine in it, ran it hard & there are valve marks,etc on the pistons..not sure if this makes them weaker but some of them are pretty deep.

 

Nothing wrong with using forged pistons on stock rods. Just make sure everything gets balanced.

 

So it doesnt put any extra wear/strain/pressure on the stock rods with using a heavier forged piston? I read that somewhere(cant remember where though).

 

Yea the heavier forged piston will put more stress/forces on the rod but nothing that they can't handle if prepped properly, but you should consider the price of reworking them compared to new rods if you plan on rebalancing anyway...

 

true..do you think the cost of them being reworked/prepped would be close to what it'd cost for a new set of rods?(eagle rods $450) and another question. If the stock rods are 6.098 & the forged rods are 6.125 will that make the forged pistons stick up further in the bore when at tdc? or is the forged piston or wrist pin, etc shorter?

 

Most aftermarket forged pistons are lighter. My Mahle stock replacements were 65 grams lighter than stock.

 

wow, no ****? I would think they would be heavier.. guess I could call or search to see how much the 347 Mahle pistons are compared to stock. Im sure their 347 pistons wouldnt be much different from the stock replacements you got from them though.