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DIY 180 Degree/Single plane/Flat plane V-8 crankshaft…


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#1 BRAAP

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Posted 04 October 2008 - 05:21 PM

DIY 180 Degree/Single plane/Flat plane V-8 crankshaft…



This thread is a spin-off of the "Exotic "SOUNDING", high revving V8!" thread, emphasis of actually building and running a production road going V-8 Z car with a custom single plane crankshaft, whether that crank be scratch built in house or manufactured by one of the few custom crank shops around.

I’d like to keep all discussions pertaining to actually building this, not just a bunch of wining and crying about "why it shouldn’t be done", or pointing out obvious issues that have already been discussed and addressed etc. We already know a 6 and a 12 cylinder have an exotic note. Lets keep this on topic of 8 cylinders, in a V configuration.

Goal;
1) To have an exhaust note that is similar/mimics the Ferrari V-8’s and/or inline 4 cylinder sport bikes in a road going street Z car that will see some autocross detail, back road corner carving, leisure jaunts across town, and to various local Z shows. Not a race car nor a daily driver.

2) Big power numbers is not the priority, exhaust note and drivability is!

3) Be the first to actually build and drive a one of kind V-8 project that is often talked about on many technical high-performance car forums, yet no one has done, (that we know of any how) and do so on a "Datsun" budget!

A question I’m sure many of you have; “Is this practical?” I’ll be the first to admit, NO, this is NOT practical! Generally we go to such fabrication extremes with our power plants for the sake of building more POWER! This project is for an exhaust note! I guess this project can be seen as an exercise in “aural bling”. So before anyone condemns this project as ridiculous, we already know it’s ridiculous, but we want to do it anyhow! Tony D. summed it up best;

Some people have a problem grasping a Machinist's Quandary.

Why does a machinist make a round ball captive within a cubic form?
Why does a machinist make a chain from a solid bar stock?

There are countless Machinists' Quandaries out there, and the reason to do them is always the same: To do them.

The thought and engineering that goes in to the front end of the Quandary is the reward. It makes the machinist think, actually think about what the project will need to be brought to fruition.

I said it elsewhere, this is not a narcissistic trumpeting of his accomplishments, but rather an informative blurb on what he is doing, and why.




Approach;
1) Do so with a 8 cylinder piston engine, in a V configuration, (sorry, no rotaries, 2 strokes, turbines, 4, 6, 10, 12, 16 cylinders etc.)

2) Do so with as many off-the-shelf new/used/wrecking yard parts as possible, (keep cost down)

3) Small Block Ford or Small Block Chevy as the foundation, (leaning strongly towards the SBC).

4) Either scratch build the crank in house or order a custom manufactured crank from one of the various custom crank manufacturers. (Our lathe has enough clear swing over the bed to allow the manufacture of a 2" stroke crankshaft...)

#2 BRAAP

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Posted 04 October 2008 - 05:27 PM

For those interested but have no idea what the difference between a single plane V-8 crank, (also referred to as a 180 degree or flat plane), and the more typical 90 degree dual plane crank, (also referred to as cross plane), this post should help clarify.


We all are familiar with how exotic a Ferrari V-8 sounds when it drives by right? Sounds a lot like a 4 cylinder sport bike, or Indy car at full song. Ferrari F-40, 308, 328, 348, 355, 360, and the list goes on. Here are 2 videos, one of Ferrari 355, the other a Ferrari 360, both are V-8’s





Domestic V-8’s from Chevy, Ford, Chrysler etc all have a coarse rumble in the exhaust note, much like the Harley V-twins. The Nissan, Infiniti, BMW, Mercedes, Lexus V-8s are dual plane crank designs like the domestic V-8’s. Ferrari V-8’s have a crisp tight BRAAAAAP in the exhaust note. Visualize it this way. Domestic V-8s as being four V-twins sharing a common crankshaft, and Ferrari V-8’s as being two 4 cylinder engines sharing a common crankshaft. It is the firing order and how those firing pulses meet up in the exhaust that gives them the distinct exhaust notes.

These diagrams should help illustrate the domestic V-8…
Posted Image

Posted Image

Posted Image

This diagram courtesy of MTCookson…
Posted Image



Another approach is to try and match up the exhaust pulses just be rerouting the exhaust primaries. In doing that we end up with 180 degree headers as used on the original Ford GT-40 race cars. (Pairing up the 2 inner cylinders of one bank with the two outer cylinders of the opposite bank). The exhaust note does become more crisp, but still has a coarse rumble to it. I have no idea why it doesn’t exactly duplicate the crisp BRAAAAP exhaust note, but it doesn’t, otherwise I just spend the time in fabricating 180 degree headers as there is PLENTY of room under the oil pan of a SBC V-8 S-30!


Here are the crankpin configurations of the dual plane and single plane V-8 crankshafts;

Note the crank pin configuration. When looking down the front of the crank, there is a crank pin every 90 degrees, on two planes, hence the name Dual plane, or 90 degree crank.

Here is how the dual plane/90 degree crank looks;
DUAL PLANE
Posted Image Posted Image

Here is Dual Plane LS1 crank and CAD rendering of a Dual Plane SBC 350 crank;
Posted Image
Posted Image


Here is how the single plane/180 degree crank looks;
SINGLE PLANE
Posted Image Posted Image

And here is a Ferrari 355 Single Plane V-8 crank;
Posted Image
Posted Image

…and here is a SBC Single Plane Crankshaft (two piece rear main seal)!
Posted Image

Edited by BRAAP, 16 July 2009 - 08:37 AM.


#3 BRAAP

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Posted 04 October 2008 - 05:34 PM

SBC cylinder numbering;
-2-4-6-8
1-3-5-7-

SBC firing order;
1-8-4-3-6-5-7-2


Ferrari V-8 cylinder numbering;
1-2-3-4-
-5-6-7-8

Ferrari Firing order
1-5-3-7-4-8-2-6



Ferrari V-8 firing order transposed to SBC and that new firing order becomes;
1-6-5-8-7-4-3-2



SBF cylinder numbering;
1-2-3-4-
-5-6-7-8

SBF firing order with single plane crank becomes same as Ferrari's.



Next, I'll cover known issues that need to be resolved and some combinations to contemplate. Stay tuned…

Edited by BRAAP, 21 December 2009 - 01:52 PM.
Fixed Transposed Firing Orders! DOH!


#4 BRAAP

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Posted 04 October 2008 - 07:16 PM

I chose to use a domestic Small Block as the foundation for more than a few reasons. Parts availability, parts selection/diversity and low cost, power train options. I strongly considered using the VH45DE as the foundation, but in the end decided that if a VH45DE version is to be done, it'll have to be after this domestic V-8 based version has passed the “Proof of concept” .

The SBC and SBF are the two options on the drawing board and I have a SBF 289 Block and crank and a SBC 350 short block on hand for mock up. The SBC is an obvious choice as it literally just a bolt in for the S-30, (I happened to have a complete S-30 JTR kit), and parts for the SBC are the most plentiful, diverse, and least expensive, all are important points for this project. The SBF offers a slightly lighter and smaller package and with its shorter deck height will be easier to match up exiting piston/rod combos. One thing that does concern me regarding the SBF 289/302 block is the very thin main web. In standard production form, the OE production blocks are known to split in half and drop the entire crank out the bottom when the combination of approx 500 HP and 7k RPM are present. This particular will rev higher, but with less power. The harmonics of the 180 degree crank will be considerably different in frequency and amplitude vs the dual plane crank. Not sure if I want to gamble on those thin main webs in the SBF 289/302 blocks holding up to the buzziness of the single plane crankshaft?...

I’m approaching the design of this crank with a very short stroke. Obvious down fall to a very short stroke is smaller displacement, i.e. lower torque output for an N/A engine, keeping the option open to boost. By very short stroke, I mean in the neighborhood of 1.5”-2.5”. For a typical SBF/SBC bore of 4” bore, that yields a displacement range of 150 CID, (2.4L) to 255 cid, (4.2L).

Displacements for 4.030" bore;
2 1/2"---stroke= 255 CID/ 4180 CC
2 3/8”---stroke= 242 CID/ 3970 CC
2 1/4"---stroke= 230 CID/ 3761 CC
2 1/8”---stroke= 217 CID/ 3552 CC
2” ---stroke= 204 CID/ 3343 CC
1 7/8”---stroke= 191 CID/ 3134 CC
1 3/4”---stroke = 179 CID/ 2925 CC
1 5/8”---stroke = 166 CID/ 2716 CC
1 1/2”---stoke = 153 CID/ 2507 CC



Reasons for such a short stroke;

1) Keep the buzziness of the single plane crank to a minimum. This is the down side to a 180 degree V-8 crank! Big 4 cylinders are BUZZY! 180 Degree V-8 cranks suffer the same 2nd order harmonic buzzzzz that a 4 cylinder is endowed with. This harmonic is exaggerated with displacement, stroke having a greater affect on that 2nd order harmonic buzzzzzz.... Some/most large displacement 4 cylinders use counterbalance shafts to help quell those 2nd order harmonics. Shorter stroke, less buzzzz… :2thumbs:

2) In building my own crank, the shorter stroke allows for more crank/main pin overlap at the cheeks which adds strength and also leaves more meat when drilling the oil feeds from the mains to the rods.

3) Higher revs without adding undue stress to the reciprocating parts, (pistons and rods). In using 4000 FPM as my guideline for max piston velocity for cast pistons, (remember, keeping this cheap), a 2” of stroke, allows for a theoretical safe 12,000 RPM! I do NOT plan to spin it that fast, 9k is plenty.

4) Longer rod to stroke ratios. Rod to stroke ratios in excess of 2:1 and even as much as 4:1! With such radical rod-stroke ratios, cylinder wall side loading is dramatically reduced, piston dwell at TDC is greatly increased, rate of acceleration the piston is subjected to is less dramatic.

5) This would be a VERY over square engine. I love OVER SQAURE engine designs. Valve area to cylinder displacement ratio is favorable, allows less valve shrouding compared to under square designs, which are benefits for higher revving powerplants…

With such a small displacement, comp ratio is factor.
Compression ratio with 4.030 bore, 2” stroke, true flat top pistons
58 CC head 7.2:1
64 CC head 6.7:1

#5 BRAAP

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Posted 04 October 2008 - 07:32 PM

Top End specs; (not quite defined, but I like the SBC option thus far...)

SBF heads;
Haven’t looked into SBF heads and available chamber sizes, (used market in the neighborhood of $600 or less).

SBC heads;
Corvette L-98 aluminum heads look the most favorable at this point. Small 58cc chambers, 1.94”/1.50” valves, intake port shape with its tall short side radius is beneficial for high velocity air, (i.e. high RPM), ports are on the small side compared to other performance SBC heads, but for small 200 CID SBC, those 165-170 cc ports should be just about right for a high performance 200 CID V-8. Same goes for the 1.94”/1.50” valve size. With a mild to moderate domed piston, comp ratio is still low enough for boost!....

Induction;
Preferably a cross-ram ITB. :2thumbs: I plan to use my WOLF 3d V-500, which supports 8 channel ignition and 8 channel injection and 16,000 RPM! More than enough EMS for this project.

Posted Image

Exhaust;
Pretty straight forward. Standard SBC/SBF headers, leaning towards 1 5/8" primaries, though 1 1/2" might work as well, dual 2" or dual 2 1/4".


Powertrain;
For both the SBC and SBF the BW T-5 should be more than adequate. I’m expecting no more than 300 HP, 220-250 lbs of torque. Maybe the Datsun 5 speed?

#6 BRAAP

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Posted 04 October 2008 - 08:50 PM

Issues that need research/attention!....

1) Oil supply;
a) Ideally I’d like to retain the OE oiling system for convenience and cost. In using the OE SBC/SBF oil pump, I’m not sure if they will continue to pump or cavitate at the elevated RPMs, (would like to be able to hit 10k!) I may mock up a SBC long block spin the pump to 5-6k, (the oil pump is driven off the cam which spins half crankshaft speed), and verify any high speed oiling issues. Possibly port the oil galleys in an effort to improve oil flow efficiency/relive pumping stress?
b) If the stock oil pump is not up to the task of the elevated RPM’s, then some other external driven wet sump arrangement, or worst case, dry sump. I want to avoid dry sump for reasons of cost, complexity and maintenance. This is to be street car, driven semi regularly.

2) Harmonic damper/flywheel/clutch;
a) Due to the RPM range, the Harmonic Damper, Flywheel and clutch will have to be semi exotic. Damper will most likely be some form of small diameter fluid damper as they are pretty universal and not really “tuned” to any particular frequency, (they are generally forgiving and quell vibrations quite well).
b) Flywheel/clutch assy will most likely take the form of a button style multi disc clutch arrangement like this…

Posted Image
Posted Image

Ignition/Distributor;
Going distributor-less ignition with the WOLF V-500. 8 individual coils ala LS-x. No issue I see other than fabbing a crank/cam trigger.

Valve train;
Ok, this is the area that I see requiring more attention/research than any other part of this project, including the crankshaft itself!

1) Valve event timing. This portion of the project is important, so as to retain as much performance as a 200 CID V-8 can produce, but due to the more pressing issue of valve train stability/reliability, compromises in the events figures may have to be made here. One thing in our favor is the relatively large port and valve size of the SBC/SBF heads compared to the per-cylinder displacement. As such, typical valve lift figures for a 9000 RPM SBC wont be needed as the cylinder volume is now much smaller. Though finding even adequate valve timing events for this high RPM small displacement V-8, (duration, lift, and lobe separation angles), for a 200 CID 2 valve V-8 that is to make power in the 4k-8.5k RPM range might be a shot in the dark. We can find tested cam specs for SBC’s that spin under 7k all day long. We can find Yester-Years NASCAR 8500 RPM cam specs, but those specs are for max output within a very narrow RPM range. I have located a knowledgeable individual whom I and most engine builders world wide hold in high regard. He might be able to shed some light on the Valve Train issue. If I can just to muster up the gumption to approach this source with enough professionalism that he will take this project seriously?...

2) Valve train stability/reliability. This is the part of the project that has me in prayer most. A valve train to see 9000+ RPM once in awhile, live between 3-8k regularly on the street! That’s asking quite a lot from a push-rod valve train. I feel light weight components will be critical in helping the valve train survive. Finding that line between, “as light as possible” and “within financial reach” is not going to be easy.
a) Roller lifter and cam vs flat tappet and matching cam? Rollers, from a mechanical standpoint seem superior and a no brainer for this application, though they are heavier and more costly than flat tappets?!...
b) Carbon fiber pushrods are most likely a necessity.
c) Rockers. Light as possible without sacrificing durability, i.e. not “sprint application” rockers. With the small displacement, maybe less than standard ratio such as 1.1:1-1.3:1? Maybe that would allow some latitude in the opening and closing ramps of the custom cam specs? (We probably should leave this bit for the cam grinder to determine?)

Again, Im leaning strongly towards the SBC...


Okie dokie… So that’s what my research has been uncovered thus far…

#7 kiwi303

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Posted 04 October 2008 - 09:16 PM

by reducing the stroke, is there a chance of reducing the weight as well by using standard length rods instead of long rods, and milling the deck height of the block down? Given that custom pushrods will be used (you mention carbon fiber) having them made shorter won't add THAT much more to the price.

how much weight would be saved taking 1/2" to 1" off the block deck height?

Edit: I realise this will affect the choices of #4 in Post 4 earlier in the thread, but given a trade off between TDC dwell and sidewall loading, how tall a rod/stroke is "perfect"? if the design ends up at 3:1 and the "perfect" ratio is 2.4:1, then would trimming the block to provide a 2.4 as opposed to 3, be beneficial?

#8 BRAAP

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Posted 04 October 2008 - 09:26 PM

by reducing the stroke, is there a chance of reducing the weight as well by using standard length rods instead of long rods, and milling the deck height of the block down? Given that custom pushrods will be used (you mention carbon fiber) having them made shorter won't add THAT much more to the price.

how much weight would be saved taking 1/2" to 1" off the block deck height?

Edit: I realise this will affect the choices of #4 in Post 4 earlier in the thread, but given a trade off between TDC dwell and sidewall loading, how tall a rod/stroke is "perfect"? if the design ends up at 3:1 and the "perfect" ratio is 2.4:1, then would trimming the block to provide a 2.4 as opposed to 3, be beneficial?


Kiwi,
The block deck of the SBF and SBC is not thick enough to allow removal of that much material. The fabrication required to make that a reality drilling new head mounted holes in the main web, cylinder stabilizers for around the deck surface, etc, it would almost be as much work as building a new cylinder block from scratch. Not to mention all the other areas that would be affected such as no standard intake manifolds would fit. Going to that extreme takes this from a “Datsun” budget to, "why not buy a Ferrari engine?"

As for the con Rods, I figured this out once a few months back, I don't recall the exact details off the top of my head, but with the SBF 289/302 block, you could use either a Datsun L-20b or Z-20E con-rod, a Chrysler 4” bore piston with its odd ball pin height, and somewhere around a 2.1” stroke, gave a zero deck. The Datsun/Nissan con-rod is stout piece, more than adequate for this short stroke.

Being as the crank is being custom built, I can make the rod journal any size I need to match the rod I plan to use. Getting the piston pin to fit the rod might require a magic wand… ;-)

#9 kiwi303

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Posted 04 October 2008 - 09:40 PM

I hadn't even thought about the standard intake manifolds...
*sits down and pulls on a dunce cap*

I don't suppose there are any blocks cheaply and readily available that can be milled down like that? It just seems to me that the longer rods give a longer area to be bent/compressed, and would be heavier than equivalent strength shorter rods. I suppose the extra ounces are the penalty for the exhaust sound.

#10 Daeron

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Posted 04 October 2008 - 11:09 PM

2) Valve train stability/reliability. This is the part of the project that has me in prayer most. A valve train to see 9000+ RPM once in awhile, live between 3-8k regularly on the street! That’s asking quite a lot from a push-rod valve train.


Obviously you havent played too much with the old pushrod 1600 motors in the roadsters... I may be blowing smoke, but I am pretty sure the old girls used to run over 8 grand on the track all day long..

still reading the rest...



Edit:

I think a talk with TonyD about what he may have seen on pushrod Datsun Roadsters in Japan might be of benefit.. I am not sure what kind of bore/stroke combination they had but I know they had high RPM pushrod valvetrains, that could sustain the tumbles from four cylinder use (as opposed to the 90 degree V8 "light duty") and I will start grilling my uncle on how they pull this stuff off.


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#11 BRAAP

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Posted 05 October 2008 - 12:19 AM

Just throwing this out for no particular reason.

The Single plane crank shaft can have the crank throws in 2 different configurations as depicted in the cheesy sketch I drew below. Green depicting the common mirror image configuration, Blue depicting the other style, (which is how a “twist” forging dual plane V-8 crank would look prior to being twisted). I plan to use the more common mirror image arrangement Like Ferrari as well as the Indy V-8’s and other F-1 V-8’s such as Infiniti, Chevy/Ilmor, (same as typical inline 4 cylinder crankshafts). In one of David Vizards books, he shows a picture of a SBC single plane crank of the other variation. That picture is the only one I have ever seen of that design and from a design stand point, looks as though it would suffer a rocking couple imbalance depicted by the tire below.

Courtesy of me.
Posted Image

Courtesy of David Vizard.
Posted Image


Courtesy of WeightSaver.com
Posted Image

#12 kiwi303

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Posted 05 October 2008 - 01:18 AM

How difficult is it to make a casting of suitable quality to form a crankshaft?

Looking at the pics above, particuarly this one:
Posted Image

I count 6 internal balances and two larger end ones, plus the shafts. it does not actually look all that difficult for a woodworker to cut out 6 identical pieces, to larger ones for the ends and shape them, then screw turned dowelling on for the bearings and journals.

If one was to make up a crank in wood, slightly oversize on the bearing faces and journals, and take that to a metal casting workshop with a good reputation and have them duplicate it in a steel casting. Would a crank shop that re-grinds old crank journals be able to grind it to a useable form? How involved are drilling the oil passages?

#13 BRAAP

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Posted 05 October 2008 - 01:37 AM

For what it would take in time, effort, materials, and the fact that I have a metal lathe, (mentioned in the first post, #4), I would much rather machine it out of a solid steel block. It will only cost me the block of steel, the electricity to run the lathe, and my time turning the handles. Even if I didn’t have the lathe, I would have another manufacturer build this crank, (forged or billet), before I would consider casting a crankshaft for 9000 RPM.
**EDIT** (Casting may be a viable option for such a project.)



Regarding the counter weights. I'm leaning towards partial or fully counter balanced vs no counter balancing.
As I understand it, fully counterbalanced pays off with less bearing wear and less harmonic induced fatigue stress at the expense of added rotational and overall mass. Minimal counterbalancing means lighter rotating and lighter overall weight, blah blah blah... This is a street engine, not a race engine being rebuilt every 5000 miles.

Oldsmobile Aurora Indy V-8, partially counterbalanced crankshaft;
Posted Image

Ferrari 355, fully counterbalanced crankshaft...
Posted Image

Various 4 cylinder crankshafts. Far left is fully counterbalanced, others are partial.
Posted Image

Edited by BRAAP, 09 December 2009 - 10:12 AM.


#14 kiwi303

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Posted 05 October 2008 - 02:06 AM

Hmm.. this is where for me, "Proof of Concept" rears it's head. As a first effort, I would personally be looking at a simple, cheap setup, where the only swap outs would be the crank and the cam, keeping the bore/stroke size standard plus keeping the 6,500 or 7,000 rev limit. Therefore leaving things so that the only top end changes need be switching the injector and ignition leads around to reflect the changed firing order. The cam need only be a standard duration/lift with the cam lobes transposed with the firing order change.

Once the engine is determined to be surviving satisfactorily, then start the new valves, ITB, new springs, smaller stroke, custom rods/pistons route for a full on skys-the-limit-revs engine.

At that point selling off the proof of concept cam and crank to another ethusiast would mean a bit of cash made available to spend on the more expensive project, and allowing someone else to enjoy the exhaust note of a flat plane.

Strokers and aftermarket standard cranks are often cast, so a 180* standard displacement standard rev-limiter should manage being cast as well, especially as it would not be used for all out power tweaks.

#15 BRAAP

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Posted 05 October 2008 - 02:26 AM

Oil feeds at the rod bearings should be 90 degrees from the point of greatest load. Points of greatest load on the rod pins are when that piston is at TDC and BDC. This illustration better explains this;

Courtesy of Callies Cranks.
Posted Image

Being a single plane crank, the oil paths will be much more simplified than the dual plane as depicted above, (thank goodness). Note, that illustration shows cross drilled main AND rod journal. For this project, the mains will be cross drilled. For the rod journals, I’m not 100% sold on the need for cross drilling. Many successful cranks are designed and ran with out cross drilled rod journals and smooth rod bearings.

Here are a few;
Posted Image

Posted Image

Posted Image


If I were to cross drill the rods, this illustration I modified represents the oil paths I would most likely use;
Posted Image

End result would look something like this 4 cylinder crank I photoshopped;
Posted Image

#16 m4xwellmurd3r

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Posted 05 October 2008 - 02:36 AM

Hey braap, earlier you had posted an image of the flat plane you described may have an issue similar to the tire imbalance, but were you talking about the imbalance pictured at the left or the right? if it was the one on the right, the large counter weights on each end look as though they would counter act that sort of imbalance, so I was just curious as to what you ment by that.

After spending time looking at the situation rationally, I decided that owning a fuel burning engine that has a rated life of about 3 miles would be a stupid move. So this afternoon I sent my pal a check for $1350.

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#17 BRAAP

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Posted 05 October 2008 - 03:23 AM

Hey braap, earlier you had posted an image of the flat plane you described may have an issue similar to the tire imbalance, but were you talking about the imbalance pictured at the left or the right? if it was the one on the right, the large counter weights on each end look as though they would counter act that sort of imbalance, so I was just curious as to what you ment by that.



Hopefully I have this right and I am not steering you guys down the wrong road regarding this...

I was referring to the imbalance on the right.
Imagine the crankshaft spinning as if it were the axle through that wheel.
Statically that crank is balanced and wont want to rock or hop when spinning. But add the pistons and rods and now as the forward piston goes up, the rearward piston is going down, (and the pair in between and mimicking this), the counterbalance mass built into the crankshaft cheeks does not cancel the reciprocating movements, (piston and upper half of the con rod), It only cancels rotating mass, (other half of the con rod and the crank pin/cheek). So the engine will want to rock with the force created by the distance between 2 adjacent cylinders as that is the nearest cancel of the reciprocating movements, which for the SBC is 4.4”. The mirror image crank design, the forward and rearward pistons are going up at the same time and the inner to pistons are going down at the same time. Canceling out each other nicely and removing any tendency for the engine to rock fore and aft. Granted, there is always a couple vibration present whenever you have 2 rods side by side. But to split that to the space of one bore center greatly exaggerates that couple force.

#18 BRAAP

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Posted 05 October 2008 - 08:34 AM

Oh my...
After a good night sleep, coming back and just reading through this mess! Oh my!!!! (I was NOT drinking, I swear!) :lmao:
Information overload
Sorry about that guys. This concept has been on my mind since the mid ‘90’s and over the years I have sporadic moments of “Lets do this”, followed by short-medium periods of exhaustive research. Then life shows up and I relax on this subject, keeping this concept at arms reach, never quite letting it out of reach, and every once in awhile, “Lets do this” hits again. Yesterday was obviously one of those “Lets do this” moments that hit pretty hard and I just unloaded most of the specific details I have been hoarding, all in a huge mess in one page of one thread! I hope that some of you are able to glean something from this, and I hope others are able to help fill in the holes I left and offer advice for the issues that need overcome. For the rest of you I hope this is at least entertaining.

This concept is real and alive, has been since the mid ‘90’s. Many factors will determine when it gets finished, one being overcoming the major issues with the valve train before I commit to a foundation to build on and start carving on a block steel. ;-) This could end up on the engine stand within a month, or could be drawn out in the design phase over a few more years. Maybe someone else will see how to make it work on their and skip ahead with their own single-plane V-8 project, (if you do, please share it…) ;-)

In the mean time, I apologize for the huge mess of info I just dumped on one page of this one thread. Due to the this being on my mind for so long and all the info I’ve amassed thus far, some bits are just "defaults” to me and were skipped over, which to those reading this becomes "holes in the project", such as the need for a custom ground camshaft with the revised firing order, the names of various crankshaft manufactures that are capable of building the cranks if we deicide not to do it in house, etc.

Thank you for allowing me to share this publicly and I am excited to see this project come to fruition.

Paul

#19 cygnusx1

cygnusx1

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Posted 05 October 2008 - 08:46 AM

What would it take to scour up a Ferrari crank out of a wreck? I am not sure about the costs but it might be worth starting with what already works. I think I might already know the answers to my question. I also have dreams of hoggin out my own car from a chunk of billet someday. ;-)

I bet if you can contract up a company to make a few hundred flat plane cranks for the SBC, you might have some customers. It would be the perfect motor for some of the HQ kits and replicas out there.

http://jalopnik.com/...-us-daydreaming

Here is a Ferrari "chop shop"
http://stores.ebay.c...sQ3amesstQQtZkm

#20 m4xwellmurd3r

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Posted 05 October 2008 - 02:43 PM

Hopefully I have this right and I am not steering you guys down the wrong road regarding this...

I was referring to the imbalance on the right.
Imagine the crankshaft spinning as if it were the axle through that wheel.
Statically that crank is balanced and wont want to rock or hop when spinning. But add the pistons and rods and now as the forward piston goes up, the rearward piston is going down, (and the pair in between and mimicking this), the counterbalance mass built into the crankshaft cheeks does not cancel the reciprocating movements, (piston and upper half of the con rod), It only cancels rotating mass, (other half of the con rod and the crank pin/cheek). So the engine will want to rock with the force created by the distance between 2 adjacent cylinders as that is the nearest cancel of the reciprocating movements, which for the SBC is 4.4”. The mirror image crank design, the forward and rearward pistons are going up at the same time and the inner to pistons are going down at the same time. Canceling out each other nicely and removing any tendency for the engine to rock fore and aft. Granted, there is always a couple vibration present whenever you have 2 rods side by side. But to split that to the space of one bore center greatly exaggerates that couple force.

Ah, ok, then I understand the imbalance you were talking about. Thanks for explaining that one to me.

After spending time looking at the situation rationally, I decided that owning a fuel burning engine that has a rated life of about 3 miles would be a stupid move. So this afternoon I sent my pal a check for $1350.

signature?
you mean you want my signature? what are ya, identity thieves? jk.
-Max, Owner of a 78 280z




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