oddballmotorsports

Ok so plotting out yet another "gee whiz" build option. destroker lq4 with small turbo(s) at this point it might be out of my budget, but still running it up the flag pole.. really just want my math checked, and can I mill the block .020-.035 if my math is correct? and yes, I know the shpiel, the answer is "because I like this idea, thats why"

03 lq4 block
4.000" bore 9.23 - 9.24 deck height

06 lr4 4.8

3.267 stroke 6.275 rod length

dss 4.005 forged pistons with a 1.305 compression distance(yes I think I'm making the plunge, readers from another thread..)

so math time 1.6335 + 6.275 + 1.305 = 9.2135

9.230 ~ 9.240 - 9.2135 = .0165 ~ .0265 in the hole.

to achieve .008 sticking out I would need to mill the block .0245ish

I know there's other ways to do this, but trying to stick with the floating pin (hopefully) 4.8 rods, and off the shelf pistons. because I think a decking and better rod bolts is cheaper than custom pistons and aftermarket rods.

can that be done on these? I'm slightly worried about that much off the top, are there any issues with head gaskets when that much meat is removed? is there something I'm missing possibly with piston choice? or should I just put my helmet back on and get back on the short bus?

A.R. Shale Targa

iTrader: (2)

If you're fortunate to have a quality crank grinder in the area;(usually a 60-70 yr old dude) have him turn the rod journals .030" under and kick the stroke out to 3.296" and run some H bearings. Gain a couple cubes; which even 2" is 5 horse on a boosted app and the crank pin will now be .014" higher @ TDC. skim cut the deck .007"-.010" and run a good head gasket.
This won't weaken the crank at all since that much rod journal material removed will allow him to enhance the fillet radius and you'll also reduce some parasitic frictional losses by virtue of less bearing speed
#WINNING

oddballmotorsports

I thought of an offset grind as a way to get the pin closer, the speed knowledge around here is dated to say the least, so I just might be able to find someone.. trying to keep the price tag as low as possible and still build a snarly ground ponder that holds together.. I have to say since the idea of this engine is high rpm, less bearing speed along with less piston speed sounds like a reliable combo.

Since I work under the Federal Mogul umbrella, trying to use as much speed pro parts as possible (employee discount baby!) any thoughts on the tri-metal speed pro race bearings?

pantera_efi

iTrader: (1)

Hi OddBall, I understand the want to spend money.
I believe that is just a waste of your hard earned cash.

I provide RaceTech Forged Pistons with a Bore/CD CHOICE at NO EXTRA COST over a shelf part.

I fit King Bearings with 1/2 the cost of FM AND a better bearing.

Yes, use your Brain Bucket and ask for my help ?

Lance

oddballmotorsports

I will.. but first I must share my engine nerd project this morning. It ocured to me, why not just throw away the notion that it has to be a gen4 piston, I reaproached it with a brand blind eye, searching for a 4" bore, compression distance, and pin diameter, heres what I got.. I also thought lets see what we get with the LQ rods and I think I have something that works.. it also forced me to make a spreadsheet that calculates everything, so now I can just input figures from off the shelf pistons. a couple things that bother me, the first working design, encorperates gen1 pistons! with .067 stick out, but with an .096 cometec headgasket, puts it at .036 quench distance with a 9.23 deck height hopefully factor in .008 for expansion, the optimum range. also they have a smaller pin, but if I were to bush the lq rods for floating pins of the same dia, get me what I need there too.. one snag, I haven't calculated, does that put the top ring too close to the top of the bore? ok enough babbling, heres the cliff notes.

IC9913KTM030 icon forged 414.97 from summit with rings designed for no clue..

1.565 compression distance

1.565+6.098+1.634 = 9.297

9.297-9.23 = .067+!

with a +cc of 6.4 and calculated from specs of all the parts puts my CR at 9.4 a little high for boost, but since I'm aiming for 7psi I think it could be doable.. I also plan on factoring in efective compression ratio with boost, I haven't got those numbers yet, but I will..

Ok so now the questions on other parts. how much for a set of pistons with rings, made for a 4.005 bore, with 1.3215 +/- some undetermined amount? (original idea with LR4 rods) the first design is with 4.030 over pistons, so there's still machine work needed, plus getting the deck to an actual 9.23. I'm down for any and all options, but cheap is the name of the game...

Che70velle

iTrader: (6)

I’m sure your aware of gen 3/4 pistons being offset pin pistons, which gives you a performance advantage, and the gen 1 pistons are not. My opinion, which is meaningless...since your only gonna play with 7 lbs. of boost, and your obviously looking to do this as “cheap” (your words) as possible, I’d elect to run a hypereutectic piston. There are coated flat top sets with rings out there for very little money.

oddballmotorsports

Ok time to put my helmet back on.. I think my original math surrounding the longer rods was wrong, I replugged everything into my neat spreadsheet and I think I have something that works with everything for a gen4 and flattops to boot. once again..

4.005b
3.267s

1.6335throw +6.275 rod + 1.33 compression distance=9.239
9.239-9.230 = .009 up

with a .051 hg, 5cc pistons and 68cc heads puts static comp @ 9.21 and 9.019 with 70cc heads so, I hope this 2nd equation is right and the first is wrong, as this would work perfectly.. someone confirm this.. or once again point out something I'm missing.. not new to plotting this out, but yes, still a newb when it comes to the subtle differences to gen 3 v8's trying to learn what i need to before I start building...

pantera_efi

iTrader: (1)

Hi OB, thanks for the PM, though I found many mistakes in your first sheet, to many to correct.
The 2nd is much better with MY choice of a HG, a FelPro of .041" thick. (.032" Squish)

I see why you what to use "shelf parts" as they cost more when you ADD the machining costs.

Lance

oddballmotorsports

pantera, I sent you a new sheet with full spec.. tell me whatcha think.. I would like to know whats wrong with the first one, to help me learn

pantera_efi

iTrader: (1)

Hi OB, yes still very poor.

Would you add the Weights and Costs to machine ?

You could provide your contact phone ?


Lance

greasess

iTrader: (1)

You say your goals are 7 psi and as cheap as possible. Why not get a junk yard 5.3 or 4.8 with gen 4 rods and pistons? In my area engines like that go for $400 if you pull it yourself. Are you aware of what people like Matt Happel have done with engines like this?

oddballmotorsports

yes that is an option I'm thinking about too. multiple paths I could take, trying to evaluate which ones best for me... ive got the LQ4 right now, just sitting waiting for me to make up my damn mind lol... interesting to note, some tuners push the lsa to 18psi!!

JakeFusion

iTrader: (7)

Lance, can you share anything about the RaceTecs you offer? Their shelf pistons are all 4" crank deals.

What options do the provide?