for V8 guys only, new engine config. Options

[messix]

well maybe not, some one has had to have done this it's seems to easy.

so i was brain storming some engine configurations based on sbc, looking around there are pistons for a 353ci [327 crank with a 400 block 6" rod].

but why not a 400 block and a 283 or 302 3" crank for a 320ci.

thats stock 400 pistons with a 1.433 compression height, and a 6" rod.

now that should work

3" stroke 1.5
piston compression height 1.433
rod length 6
______
equals 8.933


deck height 9.025
- 8.933
_____

deck to piston .092

so with a 58cc head and a .039 head gasket i come up with a 8.9/1 compression ratio.

i have seen sbc 400 engines lately for $250 or less and 283 cranks almost for free. a set of adapter bearings would do the trick.


so wadda ya think?

[Brett W]

Tim/Bynbad914 used the exact same combo. It revs well and should make a tranny life saving lack of torque down low.

Long rods are good. Too bad the engines are cast iron.

[messix]

you can go lite for $4,000 bare block in aluminum

[drive-ability]

I like the idea, I am looking in the same basic area for another motor in my V8 car. Its well known short stroke engines will rev higher theoretically, but you must have a matched set of heads along with the right cam to make it work. I am not sure how the 400 block will fair where cooling is concerned. Thats something I would like to know. My 350 runs well and has some good power but lacks the snap found in a well built engine. Keep the ideas coming (IMG:style_emoticons/default/beer3.gif)

[dakotaewing]

Would you not be better off with 5.7" rods?
I am no engine builder, but the engine builders I talked to trying to figure my configuration told me I need to stay away from the 6" rods - meaning that the motor would be a dog, and increased rod speed would not help ???

I am open to comments...

TE

[messix]

i am going with the premise that i would use aluminum heads. cooling should not be a problem.
the main contributor to cooling problems is trying to make high hp, hp = heat.
with the 320ci i'm thinking 350hp would be in the ball park. hp peak around 6500rpm torque around 5,000 rpm.

this would be with some heads flowing 195 cfm on intake. a cam with 550ish lift at around 280-290 dur.

[Mueller]

don't the 400 blocks have problems with overheating due to the siamesed (sp?)cylinders?

[messix]

Would you not be better off with 5.7" rods?
I am no engine builder, but the engine builders I talked to trying to figure my configuration told me I need to stay away from the 6" rods - meaning that the motor would be a dog, and increased rod speed would not help ???

I am open to comments...

TE

i need the 6" rod to get the piston up the hole at tdc. a 5.7 rod would put it to far down to make any compression, this due to no know to me pistons for this stroke.
as to rod speed, the short stroke of the crank effectively slows the crank/piston speeds down per rpm [distance traveled per rpm]

some thing that bugs me about this config is that it puts the piston down the hole .093. thats alot of dirty space on the flame travel in combustion chamber.

if i used a 377 piston [400 block with a 350 crank [3.48 stroke] and 5.7 rod, it has a compression height of 1.561. that would put it .036 out of the hole. head gasket of .070 puts it down .034 down for clearance. not to far off .025 for block and steal shim gasket on stock.

[jd74914]

Stupid question, but can the block be "decked" and cut down to use the smaller rods? Is that a practical thing to do, or is it just too cost prohibitive?

[messix]

don't the 400 blocks have problems with overheating due to the siamesed (sp?)cylinders?

iron heads and towing with a truck or hauling a 4,500lb car around with smog gears in mid 70's smog tune.

aluminum heads and light car and good gears and proper tune, no problem.

my buddy has a 415ci [stroked 400] with hard block [filled the lower end with a cement like compound to make lower end more stable with stroke high rpm engine] and he heat up rarely, has to be in traffic on hot day, like good guys cruise.

[messix]

Stupid question, but can the block be "decked" and cut down to use the smaller rods? Is that a practical thing to do, or is it just too cost prohibitive?

you can but then you have to machine the heads and intake. then custom order or make push rods for the valves. and decking a block more than .060 is not usually done. deck thickness is usualy not more than .500 on factory blocks

[jd74914]

Stupid question, but can the block be "decked" and cut down to use the smaller rods? Is that a practical thing to do, or is it just too cost prohibitive?

you can but then you have to machine the heads and intake. then custom order or make push rods for the valves. and decking a block more than .060 is not usually done. deck thickness is usualy not more than .500 on factory blocks

That makes sense. Thanks.

[Dr. Roger]

copied from 4wd.com:
the 400 is no different than a 350 other than the 400 has special harmonic balancer, flwheel and crankshaft. They are balanced differently.

how bout a bored 283? those things are almost bulletproof. thick walled cylinders and short stroke... hmmmmmmm...

nawwww, i still love my 350, SNAP!

[marks914]

Where do you get bearing spacers to go from small journal to large journal?

I called summit and they had no idea.

You used to be able to use bearing spacers to go from small to medium journal, can't find those either.

Anyone know?

Mark

PS
55-67 small journal
68-? medium journal
400only large journal

[andys]

Would you not be better off with 5.7" rods?
I am no engine builder, but the engine builders I talked to trying to figure my configuration told me I need to stay away from the 6" rods - meaning that the motor would be a dog, and increased rod speed would not help ???

I am open to comments...

TE

I'm not sure of the logic there. The GEN III motors all use a 6.098" PM rod for the LS1, LM7, LQ4, LQ9 etc. The 4.8L LR4 uses a 6.278" rod. Perhaps there's some anomoly with the GEN I 6" rod?

Andys

[Brett W]

There are plenty of engines that run super long rods. Many a Cup motor is built with a 6.1 inch rod. Long rods are good in a Chevy, but for the most part, it will depend on application.

For bearing spacers, check Greenwood, or some of the other high performance machine shop supply houses.

Don't mess with small journal cranks. Too much issue with finding parts. Why not order a custom crank with the Honda rod bearing. it will be much stronger. Plus you can have it internally balanced.

[messix]

copied from 4wd.com:
the 400 is no different than a 350 other than the 400 has special harmonic balancer, flwheel and crankshaft. They are balanced differently.

how bout a bored 283? those things are almost bulletproof. thick walled cylinders and short stroke... hmmmmmmm...

nawwww, i still love my 350, SNAP!

a 400 block is very different, the cylinders are siamesed [they are cast connected to the common wall of adjacent cylinders due to bore spacing and bore diameter, all other sbc have have water jacket around the cylinder.]

283 are only good for a .060 bore, this gives you a 292 ci

[messix]

Where do you get bearing spacers to go from small journal to large journal?

I called summit and they had no idea.

You used to be able to use bearing spacers to go from small to medium journal, can't find those either.

Anyone know?

Mark

PS
55-67 small journal
68-? medium journal
400only large journal

funny that summit doesn't, jegs does part number 555-25000 $69.99

[messix]

There are plenty of engines that run super long rods. Many a Cup motor is built with a 6.1 inch rod. Long rods are good in a Chevy, but for the most part, it will depend on application.

For bearing spacers, check Greenwood, or some of the other high performance machine shop supply houses.

Don't mess with small journal cranks. Too much issue with finding parts. Why not order a custom crank with the Honda rod bearing. it will be much stronger. Plus you can have it internally balanced.

custom crank? i'm talking cheap high winding hp here. stock small jounal steal crank will live just fine at 350 - 400 hp with this short stroke - low torque.

put the mone in to heads that with make power $1500. and cam/ lifters 500.

[andys]

Aren't all 283 cranks forged? SBC guru's chime in here. I think the trick is to find one that's not a red-line crank (it still has something left to grind).

Andys