pantera_efi

iTrader: (1)

Hi ALL, My customer, racing ONLY, brought me a LS-1 Block (late) with Billet LS-7 Main caps installed. (new looking, possible a "blem")
I found some core shift on ONE SIDE ONLY, the other side is a perfect 99mm bore centered well.
He IS a low cost guy with every penny accountable.

MY method is to Sleeve the one side ONLY, with the new sleeves to 4.125" as the cost is the same for either size.
I will KEEP the other side at 99mm.

What do you guys think of this idea ?

I WILL match the piston/pin weights for each bore size with ALL EIGHT as equal.

Lance

G Atsma

Sounds like a lop-sided engine....
Power pulses might be a little uneven as a result (non-flat crank)

Jontall

You need to sleeve all 8 cylinders... Call Steve and discuss:
Race Engine Development
Steve Demirjian
Oceanside, CA
P: 760 630 0450

Karlw

iTrader: (5)

That honestly sounds like a terrible idea. I would think that getting another block would be cheaper than sleeves.

00pooterSS

iTrader: (40)

Lance, are you drunk?

G Atsma

Lance, gotta call you out on this one. Tell the tight-*** customer to get another block. The customer is NOT always right...
There is a little saying- "Penny wise and pound foolish"....

pantera_efi

iTrader: (1)

Hi ALL, your words are kind, though I was asking for help with this customer's specification.
He came to me because of MY ECU-882C features :
#1 The ability to tune each cylinder separately, easily, for the correct Spark Advance AND fuel with offset/gain for each cylinder. (a bank/bank tune)
#2 The ability to create the best Stutter Table (abstract rotation) with Spark Retard for great Launch Control.
#3 The ability to Data Log with internal ECU memory, NOW Legal for 2018.

I DO KNOW this customer is CORRECT with his requirement as he is a Champion Racer.

I also know that a Flat Top piston is required with my Deck @ +.015" AND a .052" HG.

What are other problems I could face ?

The "lump" = NOT TRUE as I HAVE a BMW 750 IL (lost one side) and have installed my ECU's on other twelve cylinder engines using TWO ECU's tested by turning one off.

I also fitted the Carter Copter Chev V-6 "odd fire" using two of my ECU's turning one off, we still made level flight.

These engines ran SMOOTH, just less power.

Lance

00pooterSS

iTrader: (40)

Having one side of the engine larger than the other is going to create pumping differences and will result in a shaking engine

If you go for stoich (equal fuel ratios) on both sides the larger cylinder will be injected with more air and more fuel and push the crank harder than the next cyl that fires and then it will fire a big cyl then a small and that will result in push pull type dynamics on the crank that will equate to a rough running engine

I don't see how the crank won't receive imbalanced pulses when it has higher and lower powered "pushes" being applied

same as when you have a weak cylinder, it creates less push than the healthy cylinder which equates to a shake

Same as using a cam, the cam causes imbalanced firing at idle and makes the engine shake.f

To me it won't have a misfire but it'll act like it

Che70velle

iTrader: (6)

Lance, your building a bomb. .227” difference in cylinder diameter, from bank to bank. Will it run? Sure. Will it run right? Probably. I’d personally never use it in a race application...maybe as a bandaid fix for a street engine...maybe.
Concerns of mine are:
Compression balancing bank to bank.
Properly balancing intake flow from bank to bank.
Properly balancing exhaust flow from bank to bank.

It would be much cheaper to find another block, even including re-fitting the billet main caps. Seems like a lot of work to go the half-sleeved route...

G Atsma

Lance, nobody is saying it can't be done. It's just not a good idea, especially when fresh blocks are so easily AND inexpensively had. It's a very creative AND expensive way to end up with a really odd engine, and what point has been made in doing so?
And your customer, being a Champion Racer (as you state) but NOT a sensible engine man, should have far better sense than to do something as frightfully odd as this.
If YOU want to do this in the way of an engineering exercise, then OK. But don't think money will be saved over a new block. And BTW, there are no "late" LS1's. The last LS1 was made in 2004.

1FastBrick

iTrader: (16)

Lance,

How far over is the core shifted???

Why is it un-usable in its current state even if it's over bored?

pantera_efi

iTrader: (1)

Hi All, I like the reports, thanks.

I do know some of the GM LSx engines use a system called DOD.
My son's truck had a 5.3 with this system, ran smooth but then the DOD system broke.
The DOD I do not use and often block the passageways using a Taper Pin.

When I state "late" LS block, I mean NO breather hole between camshaft/mains AND equal head stud length.

I ask if this style of engine would make more power that an Even Bore 99mm LS-1 ?
How much more power ?

MY customer is a VERY smart engine man and his ONLY job is track racing !

Lance

G Atsma

Probably VERY smart, but not too practical. Sleeving 4 cyls. of a block, compared to finding a good used block, is wasting money.

Patron

Lance your a good guy ......

All the stuff stated makes Sense about why not to do just one side, add in that one side of the engine is requesting more air flow or CFM because of the bigger bore.
If dudes got enough $ to buy ECU's and all this just resleeve the block with a dry sleeve and have them installed. Jimbo found me a set for my 5.3 for under $1K and pay for installation(I started with a $100 layaway for sleeves). Side benefit is a larger engine. Or as the guy's said go find another block. Starting a engine build with 4 cylinders smaller and 4 cylinders bigger Who's Gonna Balance the bottom end with pistons that are different weights for each side. He's a racer tell him this Does Not Make Common Sense.

I ? this with a wop sided engine. Ask him how much it would cost to balance VS finding another block, and doing things correctly. Lance your still good but ? your buyer. If he does it correct the normal ECU would be fine and if he wants better get with you. Don't start a build F'ed up. Different head gasket bores,pistons ...etc.

Patron

Also ask him to consider regular sleeves like for older model SBC,BBC etc if that would even work being that you need to over bore for the sleeve then bore & hone the sleeve out to match. Old school way of fixing a bore.

00pooterSS

iTrader: (40)

DOD is one thing, pumping different volumes of air and fuel to different cylinders and their affect on the rotation of the crank is different. In DOD you go from 4 cyls to 8 and all are the same size. The 4 are still in balance because they all provide the same force on the crank with the firing of each cylinder

You can't have unequal forces on the crank and have a smooth rotation of the crank. Your large cyl small cyl design would have to be on different crank shafts or ran 4 cyls at a time never together in unison


Lance have you ( I know you have ) seen an engine with a cylinder or two that were down on compression? Those cylinders will have a lower percentage of contribution to the rotation of the crank. When you had a motor that had a weak cylinder.. what did it do? The motor shook because whether it had a misfire or not the bad cylinder had a weaker fire, lower contribution to the crank rotation and it created a shake and a "misfire"


If you could find a way to make all cylinder pulses equal, it could work, but I don't see how you could do that with varying cfm/fuel requirements and varying force applied to the crank in a semi random order.

Fang

NHRA Pro Stock has used much much stranger 'mismatched' engines since forever, and they seem to not rattle themselves apart. Essentially they have multiple different engines inside a single block - different port sizes/tuning, cam profiles, bore & stroke, so on... each is specifically optimized for one section of their very narrow power band.

pantera_efi

iTrader: (1)

Hi Fang, thanks for the help, I bet you have read the NHRA Rule Book !

Patron, yes thanks for the balance tip, my method is the Pin Wall and 99mm piston's Crown Thickness.

SS, yes I agree with your "tech" that when the Crankshaft Acceleration is SMOOTH, the engine will make more power. I have done so since my invention of the 60-2 (GM58x) in 1986. I have installed a 58x Target Wheel on the front pulley of a LS-3 and measured both TW's.
My direction is NOT to make Crankshaft Acceleration EQUAL side/side just Balance the two different Wave Forms to each other of the same bore.

SO I ASK "SS" : What is the measurement method you have used to determine when an engine is smooth/rough ?

I remember MANY of the persons I have known state "the engine is just an Air Pump".
I have an Air Compressor, one with TWO different sized pistons !

Thanks again to all, more input ?

Lance

G Atsma

On your air compressor, you will notice the large cylinder feeds the small one, in essence the large cyl. is a supercharger for the small one. Air compressors are not engines, Lance ;-).

Patron

I'm not the richest person nor the *stupidest ....yet crazy.

Just build the engine right enough said. If he's not willing he's *.......yet a racer or engine builder. Also to the guy speaking of NHRA this is no NHRA build they have no budget to get what's wanted. Think about it as I research and learn from NHRA guy's and incorporate into my own and a Wop sided engine with a .100+ bore difference is or never spoken about. If that was or is the case I'd being doing it or trying it myself.


Not hating but putting facts out. If Lance wants to it this way that only tells me about Lance. Good guy but if done ....... bottom line just about $! I don't read into BS. Like some dyno numbers yet run x.xxx with a trap speed of xxx. John B made 700 to the rear yet I read all the time now 620,630,650 and the engines seen have No where near what John has. I'm just saying. I'm not a buyer of BS. I'll ask or call anyone in the World to Learn. Not hating!