Checkmate007

Anyone know what we are looking at here?



I dont deal much with the LS1 however I have been told that the LS1 does not have a steel sleve. What I was wondering is what sort of coating they use on the cylinder walls? Do they coat the piston with anything?

Thanks guys

LS1MCSS

iTrader: (18)

You were told incorrectly. The LS1 does have a steel sleeve.

Checkmate007

Really I thought it was just the LS7 and LS6, are you SURE?

Does the bottom end of an LS1 resimble the photo above?

Trying to figure out some things and I figured you guys might be able to help.

A few more questions, about how many horsepower does it take to start busting the mains on these aluminum engines? Are the head bolt holes some form of time-sert (sp?) or are the threads aluminum?

Finally, are the pistons pressed or bushed?

Thanks in advance

SOMbitch

iTrader: (8)

Not sure what year it started but some later LS based engines did get coated pistons as an effort to reduce piston slap. I know it was done on 5.3 truck motors starting in 01 or 02 I think.

nine-eight

iTrader: (7)

This may be more than you wanted, but you wanted to learn a bit so here we go. I dont know how familliar you are with engines so some of it is dumbed down a bit. also, some things i dont understand well enough to explain them in perfect terminology. so dont take it that I dont think youll understand, its also because some of it I dont fully understand

first thing first, the head bolt holes are aluminum threaded. it is an aluminum alloy so it is stronger than pure aluminum by quite a bit, but you can strip them out. they are also all blind holes, unlike a traditional small block.

the pistons dowels are press-fit and are .927", slightly smaller than a traditional small block chevy.

* i refer to the ls-1 as 3rd gen chevy motor and ls-1. sorry for any confusion

bust the mains on the block?
A lot. much more than you will push through an aluminum block. anything serious, like 800+ horsepower heavily sprayed, super-or turbocharged engines will be built from a 6.0 liter truck steel block for strength. its not neccesarily the mains, but the fact that high power levels will distort the block itself, along with other destructive forces wreaking havoc on the less rigid aluminum structure. the cylinders are sleeved with a high density, centrifugally cast steel sleeve and are cast into place at the foundry. they are very strong for a sleeved block, but not strong enough to deal with those kind of forces mentioned above. imho, you should consider a steel block at power levels above 650 hp for a race motor, and you could push it to maybe 800 hp for a street car. dont quote me on that, thats a rough guesstimate on my part.

High RPM levels will also cause a block to distort. stress on the rotating components and also the cylinder walls do not follow a linear curve. the amount of stress on rotating components roughly doubles from 8 to 9 grand inside of a motor. it is exponential, not linear. a common problem with 400 small block chevy's of old had to do with this; a high rpm and high hp 400 would distort and the pistons would actually skew to the side a bit, which caused drag/ wear, lost horsepower, and reliability over long term issues. they were commonly sleeved to alleviate this issue as the cylindrical sleeve added some rigidity to the block.

also, as a side note, it is never the power level the will destroy your mains, transmission, driveline, u-joints, rear ends, things like that. the shock you place on the drivetrain of a car will dictate that. as an example, if you place wrinkle wall drag slicks on a completely stock, manual transmission camaro with an ls1 motor, and take it to a well prepped track with good traction, and sidestep the clutch, you can easily destroy the rear end(which is the weakest link in the chain on camaro/firebird ls-1 equipped car.)

At the same time, I have seen people run a 500 horsepower motor( over the ls-1's factory 350) with street tires and an automatic transmission all day long for years. the automatic is easier on the rear end, and the street tires break loose before the rear end will go off like a bomb. you can run a 7000 RPM, 450 horsepower circle track motor on a two bolt main block and have it be a reliable race motor since you do not have to launch the car in circle track racing. when you go to a dragstrip and launch a car hard, it literally tries to force the crankshaft out of the bottom of the motor and into the pavement. launching, hard gear changes, or anything else that creates a spike in the resistance presented to the motor are what makes use of a stronger main cap setup such as the ls1's 6 bolt setup. a spike in resistance like mentioned above is what will do the most damage to anything downstream of the motor. the ls1 uses a 6 bolt setup primarily for rigidity in the aluminum block. the skirt on a 3rd gen chevy motor is extended down to the point where when the main caps are installed and torqued down, they sit flush with the bottom of the block. by bolting the sides of the block skirt into the cap sides, it helps add some rigidity to the entire block. the oil pan is also a stressed member, meaning it is a rigid cast piece that is designed to add even more rigidity to the block. being that the 3rd gen chevy was designed from the ground up as an aluminum block configuration, the engineers designed all kinds of things like this to create a more rigid foundation for the motor. there is more meat on the block in many places; if you look at one from the outside you will find stiffening ribs cast into the outside of the cylinder banks that run paralell to the cylinder walls.

the heads are also a marvel. the typical valve angle for a standard small block chevy is 23 degrees. the smaller the angle, the less of a curve air has to follow to go from the intake ports to the combustion chamber on the head. therefore, more velocity is maintained and more power can be made. also, a shallower valve angle allows for a better placement of the valves inside of the cylinder so that the cylinder walls do not impede the flow of air into the motor. deshrouding the valve if you are familliar with the term. a trick thing to do with a standard small block chevy is to outfit it with an 18 degree nascar head. this of course is expensive, as you have to also have a custom sheetmetal intake fitted to your motor. big dollars, but the valve angle change is physically a huge advantage. the 3rd gen chevy uses a 15 degree valve angle from the factory, and trick flow manufactures an aftermarket head the drops down to 13.5 degrees.

the intake on the 3rd gen chevy does not carry any coolant like the previous small block chevy's. this is great because the coolant does not heat up the intake charge, and cooler air has more oxygen so more power. because of this, it is also made out of a polymer type plastic called zytel I think.... i may have the plastic name wrong. anywho, the plastic further lightens the motor and helps keep the intake temperatures down since the motor cant transfer heat to the intake as easily as if it was aluminum.

the ls-1 also utilizes an out-of-the hole piston design, meaning the piston pops slighly into the combustion chamber in the head. this is so that all of the air/fuel mixture is forced into the head's combustion chamber before ignition. this makes the motor more efficient since the expanding gasses that power the motor are, for the most part, directed down onto the piston top rather than pushing against the cylinder walls as they would on a typical small block chevy setup where some of the cylinder wall is exposed upon ignition. i beleive the amount that the piston pops "out of the hole" is .05"... I think... again i could be wrong.

another key point is the fuel injection system. many past fuel injection systems on small block chevy's utilized a "bank-fire" setup where an entire bank of fuel injectors would fire at one time, and the fuel mixture would just sit for a fraction of a second and then get sucked into the chamber when the cylinder was ready for it. a bank, if you dont know, is the cylinders in line on one side of the motor, so a bank would be four cylinders on one side and the other bank would be the other four cylinders. this system has a sequential fire system so that the injector fires precisely when the cylinder is going to need it, which helps since the atomized mixture doesnt sit still at all (for the most part). when the mixture has to hover, such as in a bank fire setup, the mixture has a chance to re-solidify and/ or drop onto the runners and you lose some atomization. the more atomized the mixture is, the better the burn in the cylinder. the fuel injectors are pointed directly at the backside of the intake valve. this is slightly debated, as some say its better when it has to travel with the air intake charge through the runner to better atomize the mixture, and other say the direct injection like the 3rd gen's is better. i dont have a clue which is true.

thats all i can come up with at the moment. please, if anyone sees a mistake correct me.

Nine-Eight

Checkmate007

Sounds good to me.

The photo I shown of the engine above is out of a 1991 Mercedes-Benz 560 SEL and is a 5.6 liter all aluminum V8 produced from the early 80's on thru the early 90's.

I am working on a project "RACE CAR" which is not produced by GM. My plans was to build and LT1 and hose the hell out of it to the tune of 500-800 total horsepower. This would be strictly a race car only mind you.

My main questions were answered and your information is much appreciated. I am building a few of the engines shown above and I wanted to ask you guys what you thought about very high horsepower and aluminum blocks. Your response was along the same lines I was thinking in that the use of high amounts of nitrous would prove to be more of a pain than going with a cast iron block.

I still wish to rebuild a few of the aluminum MB blocks but nothing crazy like I have planned for the race car. The blocks that I am building have aluminum cylinder walls, 6 bolt mains and a choice between SOHC and DOHC heads. The head bolt holes are also made of aluminum however they make these steel time-serts that screw into the head bolt holes to make them very strong.

I guess I will stick with my plans of using an LT1 block to build my nitrous monster. It was a toss up between that or a Ford 351.

So you know the LT1 also has a waterless intake manifold, however other than that I could find no other discrepancies with your information and I thank you for taking the time to share it.

nine-eight

iTrader: (7)

not a problem. and for what its worth, imho it would be a cost-effective compromise to go with a 6.0L truck iron block based 3rd gen build. some guys are getting 1200 or better horsepower out of the iron block gen 3's and the blocks come cheap. i think it would cost you less to get the power you want with that rather than an LT1. youd get the advantage of a better intake manifold design (the lt1 setup has very long intake runners and doesnt support the higher rpms, above 5500. even aftermarket isnt that great) the ls1 has a large following and a good aftermarket for parts. although the lt1 can be built into a very strong runner too. good luck!

nine-eight

iTrader: (7)

oh, and to answer your original question about the picture:

that mercedes motor is similiar in a few ways. for one, from what I can see there are no pressed-in caps to seal up the block; the threaded plugs are used.

two, the deep skirt design with 6 bolt caps is also similair.

beyond also being an aluminum block, thats all that i see off hand.

one difference is that the ls6 block, which is extremely similair to the ls1 block, has windows cast into the main webbing to the sides of the crank mains to help with high rpm breathing / pressure equalization. this way it doesnt have to add any turbulance to the oil drainage and oil pan area to equalize, which is already a factor with extreme applications of power or rpm for oil control.

but seriously, if i had any two cents at all to put into your piggy bank of ideas, id really investigate the 6.0l truck blocks. i know im repeating myself, but it is to stress a point. granted, im a chevy guy on a chevy dominated forum. im going to say this. but for what you're doing, id really reccomend it since it makes use of the gen-3 /ls-1 architecture(sp?) and you get your iron block strength. compared to a standard iron block chevy, you get the more advanced heads, roller camshaft setup, injection setup, a custom programmable computer from the factory that you can tune instead of a 2000 dollar stand-alone unit with its software. its a cheap, readily available block that can be replaced easily and found almost anywhere. its a stout, time-proven setup. being a sb chevy, its the most widely modified motor in history, the parts aftermarket is well developed, competetive, and proven. parts are cheaper, better made, with more engineering. there are battle-proven nitrous systems out there with cheaper replacement parts. the configuration allows you to swap out the .927 rods and pistons for forged units designed for the standard small block chevy, which are hugely plentiful, economical, and benefit from 30+ years of engineering and advancements.

ok. im getting off my soapbox now. thanks for listening to my rant.


Nine-Eight

Checkmate007

I am most sure the 6.0 liter truck blocks are up there in cost. I am almost positive I was told that the LS1's did not have steel sleves. You look like you been around a few LS1 internals but are your SURE? I expressly remember something that was written in publication stating that the LS7 and the L92 were the ONLY ones that got a steel sleeve.

1CAMWNDR

iTrader: (21)

All aluminum LSx engines from the 1997 Corvette LS1 up to todays Corvette LS3 have had cast in steel liners. Only the iron blocks do not have liners. The L92 block is tha same 6.0L block that is in the current LS3 so yes, all 6.0L and 7.0L aluminum blocks have a steel liner. Sounds like that article was only refering to 6.0L and larger motors. Yes there is an iron 6.0L motor that of course does not use a liner. But all of the aluminum ones do. And a 6.0L iron block can be bought from a junk yard/salvage yard a lot less than the aluminum 5.7L block.