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?

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.

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

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

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 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.

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

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.

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?

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.

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.

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!

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

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

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.

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

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

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.

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

yep!

Bunch of questions asked throughout this forum, so here is my take on this combo and so forth....

First of all don't do it. Simple as that. There are no bearing spacers that I am aware of to get from 400 journal down to 283 journals - the only bearing spacers I know of are from 400 to 350 journal. IIRC, the main sizes are this

283-early 327 = 2.350", late 327 -350 = 2.450", 400 = 2.650". My combo is a 400 block with late-327 steel crank (they made that only one year, so have fun finding one worth a damn - took me a few months of searching through all of my connections to get mine). I worked that crank a ton - it is 42lbs now. Check the specs - that crank cost me $1100 in machine work to pull that off.

SRP makes an off-the-shelf piston with a 1.375" CH 4.155" bore flattop that is perfect for 6" rods and 3.25" stroke - clean the block to exactly 9.000" deck and it is zero. With my Canfield heads deck 1/2-deg down to 58cc I am in the 11:1 range. I will change out the stock gaskets to .022" Cometics down the road and be about 11.8:1 when I just really need more power. That said, the combo I just described is basically the combo I built in a number of circle track and road race cars - one took the championship with that engine when other guys had Bowtie blocks and Bryant cranks...

If you ran the 6" rod on that short 283 stroke, the engine would be basically worthless - regardless of cylinder heads and so forth - below 6,000rpm. And I am dead serious, especially given the cam specs you mentioned (I am assuming those were advertised numbers, not .050" numbers. If they are .050" numbers, then forget the street but that would be about the right cam to launch at 6,500 and shift at 9-9500).

R/S ratios around 2.0 and higher are really for HIGH rpm applications only. Nextel cars are running 6.25-6.5" rods on 3.35" strokes for instance which is below 2.0 and check the rpm band on those engines... can you drive that on the street???

And that piston you are spec-ing is a freakin' slug, so the stresses due to accelerations on that rod would be brutal.

That said, here would be a great combo based on a crank that Eagle finally introduced...

400 block with splay-main caps added 2,3,4 bored to 4.155" with bearing spacers to 350 journals
6.0" H-beam rods (quality, lighter I-beam would be nicer but $$)
Eagle makes a 3.35" stroke crank now that you can get already lightweighted for about $1100 - all the stuff I did to mine is already done to it. Sweetness....
This requires a 1.325" CH piston and I don't have SRP/Ross/JE catalogs in front of me, but that is probably available off-the-shelf.

363 cubes of pure bliss - hahaha. Run a head that flows 290-300cfm at .600" lift and put a nice cam with that for the street and really have fun.

Or run my championship winning cam = 256/264 at .050" - .550" lift roughly (depends on rocker ratio of course) - 106deg l/c with 6deg advance ground in (that's right - a 99deg intake centerline!!). This cam will rip your heart out and slam it against the firewall of that 914. Max torque at 5100rpm and max HP at 7300rpm.

Mine made 525HP/438 ft-lb torque with a little race gas and 36deg timing and 512HP on this crap-ass 91-octane CA pump gas with 34deg timing.

Oh yeah, and decking more than necessary is always a bad idea. And running a piston any more than .005" in the hole is a really bad idea. The whole concept of chamber design and quench area goes out the window with that. In fact, some of the new theories involve running out of the hole and cutting a chamber shaped volume into the piston to reduce compression but retain quench and good flame-front.

That part # is for a medium journal to large journal.

283 cranks are small journal.

Mark


PS not all 283 cranks are forged, some 66 and later ones are steel, chevy only used forged in trucks in those later years.

yup brain fart on the spacers, i was home for lunch and my mind was too!

and 283 crank i had in mind was a truck crank a buddy has he'll give me for free.

500hp is way more than what i was shooting for. just 350 - 400hp that comes hard 4k -7k but will still run at 2k with out much fuss in a 2,300lb car.

cam in thought was a hyd roller.

and having the piston that far down the hole REALLY bothered me. thas why i was thinking of the 1.561 ch piston from the 377 config. suppose i could get the piston cut .030 to put it .006 in the hole.

now we're talking more money in machining.

just looking for somthing cheap and easy.

I had a 400 small block also, for my firt 914 15 years ago, but never used it because of the siamese cylinders. I'm curious to see how cool it would run.

Ok lets look at the numbers here. You buy

core motor for 150$
New Crank 800$
New rods 500$
Machine work 500$
New pistons $800
Good heads 1500$
Gaskets 100
Camshaft 350
Rings 100$
Oil pump 30$
Good oil pan 300$
Good Balancer 250-350

So you are at 4800$ before the rest of the stuff.

On top of all of that you will need a dizzy,, plug wires, headers, carb, water pump, lifters, rockers, and intake. Plus some misc parts.

Now you can go out an buy an LS1 used for 3500$ Spend 350 on a camshaft, 180 on valve springs, 500 on headers and give it a tune.

Suddenly your at 4600$ and are 150lbs lighter out of the box. Why waste the time and effort with an old school small block.

boy you guys really want to turn this in to high priced race motor.

now this whole premise was to use as many good value low priced and used or reconditioned parts as possible.

not a new crank
not $800 pistons, off the self forged $400
good 4340 rods $300
and much of the misc. parts could be found for less than retail.

this is just another option to build some thing different! it would sound and drive like no other sbc. it would rev so sweetly, and have a high rpm scream that curl your toes. and it wouldn't hurt a 901 tranny like a 400ft lb 350 would.

SO














FLAME ON!

I do agree there torque would be "901 friendly". You probably could do a 377 cheaper. That way you could find a forged 350 crank for cheap. Of course you could just slap a turbo on there and call it a day. (ducking for cover)

if you can't turbo a 914-4....... how....








no way can you turbo a 914-8!

the cheaper would be just a 350 build. straight up. most bang for the buck.

Agreed.

Troy, at that rate just get a crate motor....

You are really talking two different motors in this thread so hard to keep up with you... you want to spin 7K but cheap. IMO that doesn't always work. I didn't imply you needed 500HP either.

If you want to spin 7K and have 350-ish cubes or so to make 400HP you will have to choke that engine down. A 350 worth spinning near 7K had better damn well make at least 450HP or you messed up.

Want a good streetable motor at a reasonable price, buy a crate engine and shift it at 6K or so when you want to run it out a bit. My 353 cube engine makes power to 7300, so what you imply is you want that kind of engine, which frankly has off the shelf, reasonably priced stuff in it (I have SRP pistons, Eagle H-beams which are about the same $$ anymore as a good set of stockers reconditioned with ARP bolts, so why bother with that crap?) and you could use the CNC AFR heads that aren't cheap but reasonable and be about 10:1. But with a cam to make power at 7K you will make 450-475HP unless you simply fuch up. Put a 2 barrel on it or something.

Regardless of what you want, I can tell you that you do not want to build that 400/283 combo you are talking about. It will make power and run, but not "good power" because it will be an inefficient pig down low and never in the rpm range it needs to run.

And engines just aren't cheap - you get what you pay for. Carb to pan requires $$ spent for those items, the dizzy and so forth Brett mentioned. I have $9500 in my engine to spin 7500rpm all day long. That is what it will cost to live at that rpm. Period. You want to spend $5K - crate motor would be your best bet and frankly, 350HP will blow your mind in that little car. 7K and 8K rpm isn't all that it is cracked up to be - it is hard on parts and so forth. I just spent $2K upgrading my oiling system for instance because I will beat this car to death and still expect a rebuild periodically.

Good luck - I just re-read this and I sound kinda like a dick but I don't mean to I have built a ton of race motors and rebuild a ton of others when they came apart with cheap parts, so I am just trying to offer some advice. FWIW. I think you are better off just building a simple 350 or buying a crate-version.

I've got the ZZ3 crate 350ci in my car (previous owner installed) and it runs great! Lots of power everywhere, fun, and reliable. It's not a screamer, maybe 6k rpm. That said, what would you do to this engine bynbad914, to perhaps make it more transaxle friendly? Perhaps to move the power up the rpms a little and reduce torque.
Just curious...

Actually that is a perfect follow up post to show Troy exactly what I mean - 350 crate that is a great car to drive and spins to about 6K when you want to hang it out. Perfect motor for those cars.

Anytime you want to move the rpm band up, there are two sorta simple ways. On is to retard the cam you have, but that will only move things a couple hundred rpm (a lot of guys think that makes a huge difference, but 6deg retard moved my powerband 200rpm on the dyno and actually killed about 30HP too). So retarding is better for tuning the cam to the engine combo, not really shifting power.

The other is to put in a bigger duration cam. Lift doesn't have much affect and more lift with those crate heads wouldn't help much. Essentially you kinda want to ruin that engine by taking power away from it down low. The issue is the overall engine package GM has with that is really a well-designed setup, so putting a bigger cam in it won't make necessarily that much more power up top because the top end of that motor isn't setup for it. It will lose power down low which is more transaxle friendly.

My honest opinion isn't always the cheapest... but the issue really isn't the engine Upgrade the trans would be your best $$ spent as you can keep a really solid street performer with that "as-is" ZZ3. Depending on how resourceful/handy you are, it may not be as expensive as you think. I bought a good, used 930 for $2200 cash. I flipped it (cost me $1 do buy a bolt to plug the breather hole and less than 50 cents to get a brass fitting to make a new breather spot) and maybe $15 in scrap steel to make mounts to mount it. Your adapter plate would need redrilled as the pattern isn't perfectly symmetrical - I bought mine already drilled correctly from Kennedy. Then I have about $500 in my cable shifter setup with McMaster-Carr cables, a Porsche Boxster tower from a dismantler, and pieces I machined from scrap metal. Other guys on this forum have their own setups for about the same money or less even. But that $3K is the absolute best $3K I could have spent on this car. 915 boxes can be had much cheaper in good working condition.

Otherwise, if you like bump and more show than go let's say (and frankly it would still really go and pick up more power at the top and a few more rpm) you could put a little larger duration cam in it. Don't up the lift as that will just create valve to piston clearance issues (same for a lot larger duration too so you have to check that).

Thanks for the solid reply!
Sort of what I figured on the engine, and really it scoots just fine as-is.
I already have a 915 in the car and keep my fingers crossed it'll live. I do keep my eye out for reasonably priced 930s though.

to clear this up, i was just hypothesizing on the "do-ability" of a high rev motor that isn't allready out there. this was a 350-400 hp engine that answers the need for non-901 tranny killing v8.
i may have gone over board on cam spec,[i really haven't gone to far into this beyond daydreaming and a little look up on spec on pistons and and thats how i over looked the lack of adapters for the small jounal 283 crank to large 400.]
i do suspect that 350 hp would be attainable and have decent street maners, [whats a 4cyl make for torque below 2k rpm? way less than a nasty idleing v8!]

i'm am not new to building engines. i had grown up in race shops and GM dealship shops since i was 8 years old. i used to hang out at one of the well known race machine shops while in high school so that i could learn more, and swept floors and scraped grease and cleaned parts for free machine work. i learned from my older step brothers that it's better to race and build on some one else's dime than to eat top ramen cause all your money is supporting racing.
i have lost track of how many engines i have assembled, rebuilt, sorted out tuning and combo problems,. i have been on the side lines for the past 8 years due to getting married /divorced, having a kid and just having other things taking a higher priority than spending the time and money on hot rod engines.
i still help out a couple of friends with thier very stout cars [both prostreet style cars making over 700 hp] and haven't been able to help crew on the 410 sprint car team that i used to enjoy doing].
i'm old school, i haven't gotten in to the aftermarket fuel injections or crank fire and electronic fuel and ignition systems, they were just hittng the main stream when i fell off the scene.
if i won the mega buck lotto i would go nuts with all the back log of ideas and toys i have wanted. but alass i'm just a modest blue collar single dad paying child support and a mortgage. so this little 1.8
1.8L 80hp car is all i can handle right now.

the reson as to why i was going with other than a 350 is that a shorter stroke engine doesnt "feel" as stressed with cruise rpms above 3k rpm.

the shorter stroke [3.o"] also slows the piston speed down in feet per minute signifantly compaired to a 3.48" stroke. so the engine would see as high of stresses at the same rpm. the rod weight did concern me as well as the piston weight. but seeing as this is intended as a street car engine i don't feel that full on race parts and strength are needed.

F=ma, not F=mv and stress = F/A, so stress = ma/A

Instead of typing all this out, I found a good section of verbage online... stresses are not caused by velocity, they are caused by acceleration. Longer rod engines decrease acceleration, but spinning it to 8K v. 6K on a shorter rod combo is not apples v. apples - so assuming you really want to build that crazy little motor then have at it but hopefully this helps clarify your thinking...

BTW, I built a few DZ302s for Camaro drag cars - none launched below 6500rpm and all shifted about 9K. I used a 6", very very high $$ rod on those motors to keep them together because the piston is a slug, especially at 9K, including the fact I know that acceleration is decreased at TDC with that longer rod. That motor will draw very hard on the heads, but only at high rpm (note this text mentions the faster velocity draws harder = a good thing). Also the dwell time you will have with that motor will make it hard to run pump gas unless you stay under 10:1 static compression. Mine at 11:1 couldn't quite make max power at 91-octane and had slight detonation on the dyno with less rod ratio.

But Indy motors don't shift at 7K. And they have no bottom end like you want. Build what you have to build - it will run and it will make 300-400HP and you won't know the difference behind the wheel - but the combo you are implying is really a great combo above 6500rpm and would suck on the dyno v. a simple 350 I could slap together with junkyard parts, aluminum AFR heads and a decent cam for the rpm range you want to use. NOBODY at the dyno shop could believe I made over 500HP on pump gas with 353 cubes and standard port location SBC heads. My combo is considered good for 475-500 so when I hurdled that the jaws dropped. But you have at it.

Here is the text - standard engineering stuff - stolen from http://e30m3performance.com/tech_articles/...atio/index.htm:

The ratio of the rod length to stroke is called "rod ratio" and is a useful term to quantify the kinematics (relative motion) of the piston as the crank completes a cycle. Rod ratio can also be used to quantify the dynamics of piston motion (the relative forces) but that is for another article.

The equation for the rod ratio is as follows:

Rod Ratio = rod length / stroke

The total distance that the piston moves down the bore is solely determined by the stroke of the crank. But both the speed, and the acceleration of the piston are dictated by the rod ratio. The piston speed and acceleration can have numerous effects on the performance of an engine. The velocity of the piston (it's speed) can be important in determining how the intake charge is pulled through the ports and past the valves. A fast moving piston will pull harder on the ports, creating a larger Delta-P to "suck" air into the cylinder on the intake stroke. Here one might think of correlating the point of maximum piston speed to the point of maximum valve lift for example.

The acceleration of the piston on the other hand, leads to forces on the rod and main bearings, as well as on the wrist pin. These forces put a limit on the rpm's that the bottom end of the engine can reliably withstand. The rod ratio also determines the "dwell-time" of the piston at top-dead-center (TDC) during combustion. This means that the position of the piston relative to the point at which maximum combustion pressure occurs can be altered through changes in rod ratio. This could be used to try to correlate the point of maximum combustion pressure to the point at which the piston has the greatest mechanical advantage on the crank for instance. In fact, the very nature of the combustion process can be affected by the position of the piston, and how long it dwells at TDC. These are all interesting topics, but in this article we restrict ourselves to an investigation of piston displacement and velocity, and we concentrate mostly on piston acceleration.

...This series of curves shows that a longer rod reduces the maximum piston acceleration.

I just took delivery of my motor built for my conversion and I started out with basically the same criteria as Messix was proposing. I was given some good/better/best suggestions with price being one of the main considerations. After mulling it over, I went a little high-end because I figured I was building my 'dream car' and I might as well do it right. For just over $4k (Canadian) I ended up with a 327 SBC turned into a 302 with a 283 crank, full roller valve train so it can rev, and cammed to make power at high end. I will be adding electronic FI and ignition so it can be 'tuned' to run right with the teener and 901 tranny.

Hopefully I ended up with a combo that will make about 300hp, rev to 7000 but not have too much low-end torque for the 901 transmission to handle.

If that Camaro was a steel bodied car with cage, then it is a tank compared to a 914. Add to that, big sticky tires and you need torque to launch it. A 914 is not likely to be a drag car, but rather a road car. It's light weight doesn't need the low end torque expected in an otherwise heavy car. Higher end power would make the 914 a fun car without the tire burning torque that breaks the tires loose any time you apply some throttle.

BTW, you mentioned cam timing to help tune a motor combo. This s a frequently overlooked necessity. Can't just throw a bunch of parts together without understanding the need to tune the combination of parts. Your point is well taken. Additionally, you can advance or retard the cam timing to suit track conditions; the stock car guys do this.

In all these discussions, one shouldn't lose perspective that the higher the RPM capable you want the motor to be, the more money you need to put into the valvetrain and oiling. I don't see how you can build a 7000+RPM motor for cheap and have it last. IMHO.

Andys

well this was never intended to be an indepth build proposal. the address the oiling, because i would use roller lifters and rockers the oiling would be restricted to the upper end. the crank would get cross drilled lblah blah blah. all the standard oiling stuff. the pan would get a tray and scraper, and i have baffeled my own pans b4 for from stock pans.
oiling a engine that only see's the 7k rpm every once in a while isn't like one that see's it every time it's started ie race engines.

the engine that i built back in high school was a 400hp 350 with a iron crank and a budget forged piston rebuild kit from trw. it had a hyd cam and i rev'd it to 6,5k a lot. i sold that engine to a friend and he preceded to break a rocker arm [factory style stamped] so i "helped" him fix it but we pulled the heads and pan off just to take a look, all was nice and pretty. because i had been hang out at the machine shop [ dudders in kirkland] i beamed the rods and lightened them on the lower end.

so here i am rambeling on.


edit: so i was going over some of the old articles that i had saved and found one that dispels cross drilling cranks as a preformance inprovement. see i still have some rememory left!

I know many of you guys have been at this longer than me, but why waste time with a cast iron SBC. They aren't even cheap enough now to bother building up. I can make 500+ on a pump gas daily drivable LS1 engine. They are lighter and more efficient. They already come with the good stuff so you don't have to buy, roller rockers, roller lifters, 15deg aluminum heads, fuel injection, better oiling system, etc.

For our cars it just isn't worth it. You can even find the Cast iron LS series engines and buy them for cheap.

Of course since I am a boost junky, I would slap two turbos on the side of an LS and make a nice even 700hp on pump gas.

The only cheap motor is a stock motor. When you exceed the specifications of moving grandma to church you have to start fixing design flaws with American engines. The later stuff is much better.