cory32690

5.3 block with wiseco 3.780 pistons 6.125 rods and a 4.0 crank

Also has anyone ever built one like this

RezinTexas

pi*3.78^2/4*4*8 = 359.1 in^2

cory32690

Would there be any issues anyone could think of with this build

gs462

iTrader: (4)

Do you already have all the parts?

cory32690

No I was just thinking about doing it I have the block and can get a stroker crank for fairly cheap plus it would leave alot of meat left on the cylinders if it needed another rebuild

gs462

iTrader: (4)

Id look for a lq4 lq9 block they're pretty cheap. and go .030 over and make 408 cubic inches.

cory32690

I no that I was just trying to think something different

FastKat

iTrader: (10)

I have never heard of anyone running a 4" crank in a 5.3, but who knows, there might be one out there.

Would side-loading the pistons/bores be an issue?

mark21742

Sounds like something that could handle a bunch of boost and or n2o

scj

iTrader: (89)

Sounds like a interesting little stroker. 360. Usually boost tends to match well with big bore small stroke, for the revs. I wouldn't put this on boost. Nitrous, or NA would be pretty stout. Not sure what this small bore/ long stroke setup would do power charactaristics wise. I'd throw it together with budget parts just to see what it's got.

bww3588

iTrader: (49)

I think crashing rods into the bottom of the bore might be more of an issue. With the smaller bore of the 5.3, clearance might be at a premium.

scj

iTrader: (89)

But you can put a 4" crank in an ls1 and it's bore is roughly .2" larger than that of the 5.3. You may have to do some clearancing, but I don't think it would be that large of an issue for a machinist to deal with.

mark21742

Most of the time clearance isn't a problem with a 4" stroke but very close, but 4.125" needs more work...might just need a small spot at each side of the bottom of the cylinder walls botched to clear the big end of the rods.

Id like to see someone use a 4.8l crank in a 4"+ bore with crazy boost to see just what it could do/ rev to.

bww3588

iTrader: (49)

generally, under square engines arent power houses. thats why you dont see a whole lot of 383 builds out of LS1's. the power potential to dollar ratio is pretty lack luster. esp when stepping up to a 4 inch bore block with the same stroke nets you quite a bit more power and torque for roughly the same price.

I can see this 360 cube engine making more torque than anything. would make a good engine for someone looking to up the towing power of a truck, but in an f-body or similar, probably wouldnt be as good of a performer as say a 408/402. I can see power and torque levels being on the same plane as a 383 LS1, but a reasonable amount less.

KCS

iTrader: (20)

Just because of the lack of displacement it probably won't make as much as a 383 or 408, but undersquare engines can be more efficient in lower RPM engines like hydraulic roller street engines. It would probably be a pretty nasty little motor with a T70 or T76.

bww3588

iTrader: (49)

I understand the lack of cubic inches, and the fact it is undersquare is what makes is more efficient at lower RPM's, which in turn, combined with the right cam, will make for an off idle torque monster. I agree with that. However, I still beleive that an oversquare engine would be better suited to a FI build.

KCS

iTrader: (20)

Why would you think a large bore is better suited for a pump gas hydraulic roller?

bww3588

iTrader: (49)

I'm not sure what bore to stroke ratio has to do with the design of the lifters and fuel it runs on...

A hydraulic roller engine can be built to run to higher rpm's as well as low...most of it is in the cam. You know this.

Larger bore, short(er) stroke engines generally respond to FI builds better than small bore large stroke engines.

KCS

iTrader: (20)

Pump gas hydraulic rollers are limited in RPM and octane, unlike most dedicated race cars that use solid rollers and race fuel. While a HR could turn "high rpm", it's still limited compared to solid roller combinations. Most HR setups that spin over 7500 RPM actually mimic a solid roller anyways.

So when you're limited in RPM, you're only going to be able to take in X amount of air naturally aspirated. With boost, it's not the RPM that limits the amount of air injested but the point at which the fuel/air mixture detonates. In either case, its very important to make the most out of the combustion which is where the undersquare combinations shine.

Larger bores are better suited to an engine that can run higher RPM and higher octane fuels.

FastKat

iTrader: (10)

Original poster - what are your goals? What do you want out of this engine? (Performance, etc)