24 replies to this topic

[marion5drsn]

. [

[da Silva]

I have an -73 Saab 96 V4 as an vintercar so this is interesting stuff for me.
As for the motorcycle engine I can´t see why an V4 should be recognized for being smoother than an inline four. An Japanese inline four is about the smoothest thing you could come across IMO.

[da Silva]

I´m on the case! I saw that many versions of the Honda V4 had an 360 degree crank but that were more of the high performance versions, like the VFR400R and the RC30 etc.
The other ones had 180 degree cranks. Couldn´t yet find anything about the counterweights.
cheers

[da Silva]

I found an question that remained unanswered but I´ll post it here if any interest could be found in it.


quote

Down through the years, I've read remarks from road test writers in the
Moto-rags about 180 degree and 360 degree crankshafts in Honda V4 engines.
Now, I know the difference between 180 and 360 crankpin arrangements in,
say, a parallel twin. Or in an engine with the cylinders split 180 degrees
like a BMW. Or even in a V twin if it had separate crank pins for each
cylinder. What I do not understand is the point of reference when these guys
speak of a 180 or 360 arrangement in a V4. Is the 180 or 360 degree timing
referring to the front pair of cylinders as a unit and the rear pair as a
unit? Or the left two and right two? For that matter, how many crankshaft
throws DOES a VFR have? Two or four? As I recall from memory, the original
(1984?) models had a 180 degree crankshaft and were considered torquers, but
emitted a soul-less drone that the sales people hated because it didn't
'sound fast'. (Which says all that need be said about the skills of most
moto sales wonks.) In about 1986, Honda made a bunch of changes; geared
camshaft drive, no more forked rocker arms, correction of coolant leak
problems, and a 360 degree crankshaft. The magazine buzz at the time about
the crankshaft change was that Honda wanted the V4's to sound more like the
pulse-quickening yowl an in-line four makes. (I might have the descriptions
of the 180 and 360 versions reversed here - can't be certain, but the
differences between the two were certain.) The 180 arrangement is in natural
balance as the throws are opposite each other, but the power pulses are
uneven (two hits - two exhausts - two hits - etc.). The 360 has even firing,
one on each crank revolution, but the throws and rods are adjacent and
require a considerable crankshaft counterweight to cancel vibration.

So, my question(s): How many throws does a VFR crank have? Seems like it
would have to be four. Are the pairs front-and-rear, or left-side and
right-side? That is, are the pistons in the front pair and rear pair
adjacent or opposite? Which crankpin arrangement does the current VFR have?
Besides the sounds they make, is there any REAL difference in performance
that comes from crankpin arrangement? Like maybe better inherent balance,
less vibration, or something?
quote


picture Honda VFR750R (RC30)
http://www.honda.co....mage/vfr_00.jpg

picture oval valve NR750
http://www.honda.co....image/nr_00.jpg

VFR750F
http://www.khulsey.com/honda.jpeg

All I could find..

[WPT]

Early Honda V-4s had 360 degree cranks. The 1986 700- 750 VFR changed to a 180 degree crank for "better" exhaust noise. The racing versions used a 360 degree crank to take advantage of the equal exhaust timing between the two front cylinders and between the two rear cylinders. For balance considerations, think of two 90 degree V-twins running side by side. To eliminate secondary couple one can use 180 or 360 degree crank. Yes, there is secondary inbalance in this design, but primary inbalance is eliminated with proper counter weighting (same as a V-twin). A 90 degree V-4 is a very smooth running engine. What vibration is there makes no difference.

[WPT]

The secondary inbalance adds in an inline four too. On larger displacement inline fours one sometimes finds a double speed balance shaft, this to tame the secondary inbalance. Try riding a 90 degree V-4 and see for yourself how smooth it is. As I said above, once you understand how to balance a 90 degree V-twin, you will understand why the V-4 version is smooth. Not perfect, but plenty good enough. BTW, the smoothest running motorcyle engine I have ever riden was a Honda CBX (inline six), what one would expect from theory.

[WPT]

Having trouble posting!

[WPT]

Honda's 1986 VFR-750 has a 180 degree crank. The firing order and crank rotation interval is: (1)-180-(3)-270-(2)-180-(4)-90-(1). Here the rear two cylinders are from the rider's left to right no.1 and no.3, and the front two cylinders are from left to right no.2 and no.4. The crank rotates in the same direction as the wheels. I have owned one these bikes since new and can attest to its smoothness. In fact, due to the way the secondaries add and the phasing (all other things being equal), a V-4 is smoother than an inline four.

[WPT]

Inline fours and 90 degree V-twins and V-4's have perfect primary balance. The secondary forces in an inline four are in phase, so if the magnitude of the secondary for one cylinder is 1, then the whole engine has a magnitude of 4. In a V-4 if the magnitude of the secondary for one cylinder is 1, then the whole engine has a secondary magnitude of 2.8 (this due to phasing and vector addition). Conclusion, everthing else being equal, V-4's are smoother than inline fours.
I should say here that due to the cylinder axis offset to accomodate the side by side rod placement in V-4's, there is a slight primary couple. Also that the magnitude of the secondary forces for a one cylinder engine is about 1/4 of the magnitude of the primary forces.

[da Silva]

Another question I found and it was answered by Ian of Drysdale Australia
I was looking for information about the Honda V5...
Quote:

Can you please expand so I can understand this?
> How does stroke:rod ratio relate to cylinder angle?
> SNIP
> > Of course there is another thought - Honda tend to
> > use 1:1.90 stroke to rod ratio in most of their high
> > performance motors.
> >
> > Number crunch this for maximum overall piston interia
> > for a V twin ( and 360deg. V4 ) and you get 75.3 deg.

The trouble with a 360 deg V4 is that 2 pistons are stopped
simultaneously at one time. This means that the crank needs to
be heavier to stop the motor being "lumpy" because a 90 deg.
cylinder angle has the other 2 pistons far from their max. speed.

If you want the lightest crank then you maximize the piston
interia. ( Given that you have already decided on the 360 deg.
V4 configuration ) The best inertia has one piston at it's
highest speed when the other is stopped. So with the
almost universal Honda rod to stroke ratio of 1:1.90 - this
works out to 75.3 degrees. ( A triangle with the "adjacent"
set to 1.0 and the "hypotenuse" set to 3.8 )


Cheers IAN


--
DRYSDALE MOTORCYCLE CO..
AUSTRALIA
PH: +613 9562 4260
FAX: +613 9546 8938
GP PROJECT SITE:
http://www.22000rpm.com
750-V8 & 1000-V8 MOTORCYCLES,

Check out that site, there is 2 files with sounds from his own 750 V8 and an Moto Guzzi 500 V8

[WPT]

Ian is incorrect. A 90 degree V-4 with a 360 degree (or a 180 degree) crank does have two pistons reversing direction at one time (an inline four has all four pistons reversing at the same time). However, the momentum of the other two moving pistons is very high, not at their max speed, but close to it.

[WPT]

The firing order and intervals given by me for the Honda VFR V-4 with 180 degree crank show 720 degrees of crank rotation to get back to no.1. Also, having crank throws 180 degrees apart does not mean there is balance, if there is an offset there will be a couple. Couples must sum to zero about all three axis for there to be balance. I suggest you ride a V-4 and see for yourself!

[WPT]

The drop in piston velocity from 75.3 degrees from TBC to 90 degrees from TDC is about 3%. This is far from maximum velocity?

[WPT]

Honda uses the firing order that works. What don't you understand about this engine that has you so skeptical?

[da Silva]

Picture of Honda RC30 crank. In theory it´s likely to see the same balance of an 360 degree V4 as an 1 cylinder engine.

http://www.home.aone.../VFR/RC30_E.JPG

[da Silva]

Thanks alot for the drawings! The 1-4-3-2 sounds good to me!

I don´t know but it´s easy to imagine that the V4 90 degree with 360 crank is an free reving engine! The forces on the crank should be less than of the one with 180..

I can look if I can find an sound file with the 180 and 360 crank layout just to see if there´s an different sound that everyone could hear.

[da Silva]

I found 2 sound files here but they were from 180 degree cranks VFR800´s

http://www.cyberspor...ds/rawsnds3.htm

Seems to be an problem with uploading only that soundfile. Go to the buttom of the page and you´ll find the VFR 800´s

choose Sounds, and then Rawsounds3 then you´ll find it..

[WPT]

Yes, the RC-30 crank is a "360" degree crank. The firing order is: (1)-90-(4)-270-(3)-90-(2)-270(1). For this engine, and others, Honda placed the cam drive in the center, that's why the four main bearings. They could, and have , placed the cam drive at the end of the crank thus reducing main bearing count to three. This engine is in perfect primary balance if the counter weights on each throw is 100% of the reciprocating mass for one cylinder.

[WPT]

As stated else where, 90 degree V-4's have perfect primary balance, and the secondaries add. The secondaries do not balance in this engine design. The balance for this engine design with either a 360 degree crank or a 180 degree crank is the same.

[Jonathan]

Originally posted by da Silva
I have an -73 Saab 96 V4 as an vintercar so this is interesting stuff for me.

The old 60 degree Ford Cardnal / German Ford / SAAB engine is a delite. While somewhat prone to oil leakage, and lacking something in the upper RPM ranges, this engine is notable for its phenomenal durability. Having said that, it has a characteristc slighty rough idle, that even its counter-rotating balance-shafts cant successfully mask. The SAAB V4 is an an excellent winter car, even if it lacks the smooth belly pan of the older two-cycle models. I miss mine.

Ninety degrees is indeed the optimal layout for a V-4 engine.

[da Silva]

Originally posted by Jonathan


The old 60 degree Ford Cardnal / German Ford / SAAB engine is a delite. While somewhat prone to oil leakage, and lacking something in the upper RPM ranges, this engine is notable for its phenomenal durability. Having said that, it has a characteristc slighty rough idle, that even its counter-rotating balance-shafts cant successfully mask. The SAAB V4 is an an excellent winter car, even if it lacks the smooth belly pan of the older two-cycle models. I miss mine.

Ninety degrees is indeed the optimal layout for a V-4 engine.

Which year/model did you have?
It´s an really good winter car but I wish I had an gearbox heater! The gears are so hard to
shift when the car/gearbox is cold so you have got to have plenty of time when you´re traveling..
Double clutching and everything is needed.
And it leeks oil! Still my father desambled the engine for not long time ago around and made an
easy overhaul on it. New gaskets everywhere but still it leaks oil quite a lot

Pity this discussion didn´t have started earlier because I would have been much more interested in the engine and the restoration of it much more then. I don´t consider it especially smooth at any rpm but midrange it goes quite ok.

[Jonathan]

Originally posted by da Silva
Which year/model did you have ?

My parents, starting with a maroon two-cycle 1957 SAAB 93-B (that my mom purchased before she even met my dad), went through a string of various two-cycle models (that typically only lasted about 8 years before developing body rot, and being replaced), but we only had one four cycle V-4, an olive green 1973 model.

While my first car was an older model rusted out 1967 SAAB 96 two-cycle (with oil injection, and surprisingly powerfull engine), I more or less inherited my parents V4, a 1700 cc model, which with US mandated emmission controls and a Ford "motorcraft" carburator, only produced something like 65 BHP, yet had a rather short final drive gear box ratio that made highway travel more tiresome then normal, and limited cars top speed to something in the ~90 MPH (150 kph ?) range. Also fuel economy in that V4 was around 19 mpg. With such "short" gears i did find myself able to accelerate away from stop lights rather quickly. If my memory is any good, I think I was in 4th gear around 30 MPH. One of my fondest memories of that car was in winter time travel, when encountering about a 1/4 mile of backed up traffic queued up waiting for a green light at an intersection on a what was normally a two-lane road, but had been only plowed out to about 1 1/2 lanes (leaving a 1/2 lane of largely unused road on outer edge, and a rather tall snow bank), it didnt take me long to detirmine that the "wait" was going to be about 45 minutes just to reach the intersetion. Being young, in a hurry, and having the SAAB, it didnt take me long before I put two wheels up on the snow bank, and motoring along at 25-30 MPH with a fair amount of wheel spin I was able to reach the intersection in 2-3 minutes that thankfully turned green just as I aprouched it. While what I did was perfectly safe had the local Police department managed to catch me executing this manouver I would have been for sure issued a traffic ticket of some sort.

After working at my first job (about twenty years ago) that required a great deal of lengthy highway traveling, I puchased a new 1982 Toyota Tercel FWD, that while much more fuel efficient and quiet in highway operation, lacked the ride height, road-feel and predictible handeling characteristics of the SAAB.

[Jonathan]

Originally posted by marion5drsn
I don't recall that engine was ever used in the U.S.A. but it does seem that it would have been better to just use a four cyl. inline style. I have been trying to do a V-4 @ 60 degrees and it just doesn't work. No matter what I do either the thing has all sorts of Secondary Shake or it is going to shake due to having an uneven firing order. I guess that the engineers at Ford in Germany just threw up their hands and said to go ahead with it. Then stuck in the counter-balancing device. The way I see it no counter-balancing device can do the job like another conrod setup in proper phase. It just won’t perfectly duplicate the shape and pattern of the conrod/piston that is in the engine. They might come close but never exactly. M.L. Anderson

Nope. The 60 degree V4 engine was designed and engineered by the good ol' boys at Ford Deerborn, USA. Robert McNamera wanted Ford to build a safe, sensible and efficient American car, and commissioned Ford to develope what was known as the "Cardnal" project. Thirty million dollars into this effort, after McNamera had left Ford to serve under the Kennedy administration, Lee Iaococa stepped in, killed the entire project and commissioned a hasty restyle of the Ford Falcon that was to become a fantastic run-away sales success: The 1964 1/2 Ford Mustang. Ford's Carnal project was then tossed accross the pond to Ford Germany who then produced the V-4 for a few years before selling the tooling to SAAB. I dont think Ford Germany did any development work on the V-4. All they did was build them using Ford USA's tooling. Ford USA also built the V-4 for use in industrial applications for a number of years during the 60ies.

The same 60 degree tooling used in the V-4 was also used by Ford to produce the 2.8 liter and 4.0 liter 60-degree V-6 engines that were at one point commonly used in the German Ford Capri import, the early Ford Mustang III's and the down-sized Ford Bronco II, and early Explorers. So the resoning behind the 60 degree layout was more to share tooling costs within an existing engine family, then in any particular belief in superior packaging of the 60 degree layout. Interestingly enough Ford used two-cycle SAAB 96's as "test mules" when testing the V-4 and other Ford Cardnal components, and the earliest Ford Mustang concept/show cars also used the V-4 engine.

[WPT]

A 90 degree V-twin with two throws would shake about as badly as a paralle twin. As engineers in Italy, France, Japan, Australia, and New Zealand have all used single throw cranks for this engine design (for good reason), don't you think your understanding of this subject is lacking?

[da Silva]

Jonathan

Thanks for charing your car story
I havn´t been using the Saab for an week now, too much salt on the roads and my father dosn´t like that I´m driving it during winter time, mainly because the previous owner (an old lady) never did so it´s actually a shame to do that. The car was an bargain so I could resist, 700 euro and only 125000km.
It´s not totaly rust free but only on the fenders and not more serious than that. I´m driving it carefully and just for the fun of it.

I would love to have an 850 sport or Monte carlo..