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DFV bad vibrations?


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#1 Big Jim

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Posted 22 November 2006 - 17:04

In John Horsman's new book "Racing In The Rain", he relates as to how vibrations from the DFV engines in the Mirage/GR cars caused problems. Did F1 cars suffer from the same problems? I don't think that I have read anything about this subject before.

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#2 petefenelon

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Posted 22 November 2006 - 18:35

Originally posted by Big Jim
In John Horsman's new book "Racing In The Rain", he relates as to how vibrations from the DFV engines in the Mirage/GR cars caused problems. Did F1 cars suffer from the same problems? I don't think that I have read anything about this subject before.


Yes. Tony Southgate was used to designing V12 cars at AAR and BRM. When he did his first DFV-powered F1 car for Shadow the damn thing virtually shook itself to bits...

#3 JSF

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Posted 22 November 2006 - 19:47

Wirelocking pliers are your best friend when working with V8 race engines in general. :D The DFV was notorious for vibration issues in the early days, they refined it somewhat with changes internally, but they still require a lot of prep work on the chassis to cope.

#4 David M. Kane

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Posted 22 November 2006 - 22:06

Whenever I accidently lean my helmet against the rollbar of my March 741, the helmet buzzes like an electric razor with a high pitch noise and vibration...and that's with a modernly maintained DFV.
We constantly check everything for signs of vibration fatigue. BUT, nothing in the day could consistently compete with the DFV for many, many years...

#5 bradbury west

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Posted 22 November 2006 - 22:22

I always understood, IIRC, that the DFL was even worse, not a useful attribute on an endurnace engine.

Roger Lund.

#6 bradbury west

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Posted 22 November 2006 - 22:22

or even on an endurance engine.

RL

#7 Bill Becketts

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Posted 22 November 2006 - 22:43

Hans Stuck told me that when he drove the DFL powered Sauber at Le Mans, during practice, he found the handling was not fully to his his liking.

A quick inspection revealed that (Due to engine vibration), the tub was connected to the engine by only one of the four bolts that were usually employed to keep the two halves of the car together!!

He declined to drive the car for the race....

#8 JSF

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Posted 22 November 2006 - 23:46

:lol: Most Stressed and semi stressed engine installs use just four mount points to hold the rear assembly to the tub, our 9 litre March CanAm car is constructed that way.

#9 cosworth bdg

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Posted 23 November 2006 - 00:07

Originally posted by JSF
Wirelocking pliers are your best friend when working with V8 race engines in general. :D The DFV was notorious for vibration issues in the early days, they refined it somewhat with changes internally, but they still require a lot of prep work on the chassis to cope.

Just look at the problems encounted with the REPCO HOLDEN F5000 Flat plane crank engine, they were a disaster when used by the inexperienced .....

#10 FLB

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Posted 23 November 2006 - 00:58

Originally posted by David M. Kane
Whenever I accidently lean my helmet against the rollbar of my March 741, the helmet buzzes like an electric razor with a high pitch noise and vibration...and that's with a modernly maintained DFV.
We constantly check everything for signs of vibration fatigue. BUT, nothing in the day could consistently compete with the DFV for many, many years...

:lol: I watched a DFV idling in a McLaren M26 at Mont-Tremblant one year, at close proximity. Even though the engine was only at 2500rpm, the whole car seemed 'fuzzy' because it was vibrating...

#11 cstlhn

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Posted 23 November 2006 - 02:11

Whay is the route cause of this vibration? Firing order? Crankshaft dampening?

#12 canon1753

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Posted 23 November 2006 - 02:23

I seem to remember a C2 team at Lemans one yr had a huge lead. The DFL blew up because the revs that the team told the drivers to use to finish was right in the middle of one of the Cossie's worst vibrational periods. They realized their error, but after an hour or so at that vibration level, the damage was done. I think it was the 1989 Lemans.

#13 Ray Bell

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Posted 23 November 2006 - 04:18

Somebody should invite Marion Anderson in on this conversation...

Check his long thread on the 90 degree crankshaft for V8 engines in the Technical Forum, and also check out the comments on flat plane crank usage in this thread.

#14 Henri Greuter

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Posted 23 November 2006 - 07:31

Originally posted by David M. Kane
Whenever I accidently lean my helmet against the rollbar of my March 741, the helmet buzzes like an electric razor with a high pitch noise and vibration...and that's with a modernly maintained DFV.
We constantly check everything for signs of vibration fatigue. BUT, nothing in the day could consistently compete with the DFV for many, many years...



David, since you can check it out , how is the actuial firing order of the ignition on a DFV?


Henri

#15 Catalina Park

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Posted 23 November 2006 - 08:22

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

Cylinder configuration:
Front
5-1
6-2
7-3
8-4
rear

Hope this is right!

#16 Allan Lupton

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Posted 23 November 2006 - 09:12

Originally posted by cstlhn
What is the root cause of this vibration? Firing order? Crankshaft damping?


There's another thread (on 90 deg cranks, in the technical forum, I gather) where this is fully explained, but the simple reason is unmatched secondary forces/couples in a "flat crank" V8. The two-plane crank is used to conteract that, at the expense of a complex firing order and difficult inlet and exhaust tracts (unless you have individual stubs for both) and the awful V8 pulsing noise that ensues :lol:

#17 Henri Greuter

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Posted 23 November 2006 - 13:08

Originally posted by Catalina Park
Firing order 1-8-3-6-4-5-2-7

Cylinder configuration:
Front
5-1
6-2
7-3
8-4
rear

Hope this is right!



Thanks Catalina!

Henri

#18 David M. Kane

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Posted 23 November 2006 - 14:21

Chuck Cornelison at VDS Race Engines has some info on his site:

www.vdsraceengines.com

#19 Ray Bell

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Posted 23 November 2006 - 19:48

Originally posted by Allan Lupton
There's another thread (on 90 deg cranks, in the technical forum, I gather) where this is fully explained, but the simple reason is unmatched secondary forces/couples in a "flat crank" V8. The two-plane crank is used to counteract that, at the expense of a complex firing order and difficult inlet and exhaust tracts (unless you have individual stubs for both) and the awful V8 pulsing noise that ensues :lol:


http://forums.autosp...&threadid=50521

http://forums.atlasf...&threadid=50722

Marion had a few goes at getting this subject up and running. Later he got absorbed about the efforts Oakland/Pontiac and Oldsmobile went to in overcoming secondary shake in their shared engine of the late twenties and early thirties.

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#20 kayemod

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Posted 23 November 2006 - 19:55

Originally posted by Allan Lupton
.... and the awful V8 pulsing noise that ensues


Love it!

#21 bschenker

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Posted 23 November 2006 - 20:13

Anyway here the date from Cosworth 1969

Posted Image

#22 bschenker

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Posted 23 November 2006 - 20:27

Sorry here the other one

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#23 Catalina Park

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Posted 24 November 2006 - 08:31

Thanks Beat, that is great.

#24 Henk Vasmel

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Posted 10 December 2006 - 23:56

So where does the famous 2993 come from? The numbers on this sheet don't add up (multiply actually). Maybe a slide rule was used in those days, or an approximation of the value of PI, but my spreadsheet comes up with different numbers, and I have never before been able to come up with 2993.
I do not know whether the DFV was built to metric or imperial dimensions, but in either case my results are different. If we select metric, the dimensions 85.6 and 64.8 result in 2983 cc. If however we take Imperial, the 3.373 and 2.55 add up to 2987 cc. If you start playing with 8th or 16th of an inch, you very soon end up with a 3005 cc engine, 3 3/8" and 2 9/16" give that value.

Anyone knows the facts?

Regards

Henk Vasmel

#25 Henk Vasmel

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Posted 11 December 2006 - 00:01

And after all the number crunching I forgot the original point I wanted to make, about the vibration level. Niki Lauda did his first Grand Prix in a March 711, and the it was 12 Cylinders all the way. First BRM, then Ferrari, and finally Brabham-Alfa. In his final practice session (in his first career) he encountered the BT49, which is arguably the best Brabham ever. The sudden vibration level was one of the factors which made him decide to quit there and then. At least that is the story he published in one of his German Language autobiographies (Protokoll ?)

Regards,

Henk Vasmel

#26 Wilyman

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Posted 11 December 2006 - 03:37

I'm probably well out of my depth here among the knowledgable.

In conversation some time back with a former Brabham team mechanic he mentioned vibration problems with Cosworth engines. Now i'm not sure if it was the four cylinder or the V8.
He said that vibrations were being caused by the camshaft gear train. Belt technology at the time hadn't progressed enough for it to be adapted and to possibly eliminate the vibrations.

It's all yours.
Wily.

#27 Allan Lupton

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Posted 11 December 2006 - 09:47

Originally posted by Wilyman
I'm probably well out of my depth here among the knowledgable.

In conversation some time back with a former Brabham team mechanic he mentioned vibration problems with Cosworth engines.


See (my) post no. 16 above.

#28 Jerome

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Posted 11 December 2006 - 14:44

Well, that's strange. I remember Niki Lauda talking about the difference between the Ford Cosworth engine and the TAG Turbo, and his immense satisfaction he was rid of the vibration of the Ford.

BUT: in the same interview he also said the vibration on the Cosworth was done on purpose, something to with the fuel transport above the engine.

Where did I read it? In an interview with Lauda in GPI international, it was shortly before the McLaren TAG Turbo would make it's debut on Zandvoort, 1983.

#29 Allan Lupton

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Posted 12 December 2006 - 08:26

Originally posted by Jerome.Inen
I remember Niki Lauda talking . . . in the same interview he also said the vibration on the Cosworth was done on purpose, something to with the fuel transport above the engine.


Don't forget there is a long tradition of journalists getting mis-information which is then published as "the truth"!
Sometimes it was(is) merely intended to mislead other teams, sometimes it is/was because the journo in question was too thick to realise you were talking cobblers - and sometimes it was/is because the driver in question was too thick to realise he was talking cobblers. :)
Of course, as Martin Brundle said on air, "if your name is Schumacher, you're allowed to talk cobblers" :lol:

#30 Jerome

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Posted 12 December 2006 - 18:51

Very true Lupton,

But I remember a two part series in GPI about the farewell to the Cosworth engine... in which Duckworth said the same thing, or so I remember...

#31 cosworth bdg

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Posted 15 December 2006 - 03:48

I know this is of topic, the final nail in the coffin for the Repco F1 engine was vibration and the problems caused by this condition-----------------------------------

#32 cosworth bdg

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Posted 15 December 2006 - 03:54

Originally posted by Allan Lupton


Don't forget there is a long tradition of journalists getting mis-information which is then published as "the truth"!
Sometimes it was(is) merely intended to mislead other teams, sometimes it is/was because the journo in question was too thick to realise you were talking cobblers - and sometimes it was/is because the driver in question was too thick to realise he was talking cobblers. :)
Of course, as Martin Brundle said on air, "if your name is Schumacher, you're allowed to talk cobblers" :lol:

How very true in what you have said---------------

#33 m9a3r5i7o2n

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Posted 23 December 2006 - 19:36

Quote fron JSF 22-Nov-06 19:47 3
Wire locking pliers are your best friend when working with V8 race engines in general. The DFV was notorious for vibration issues in the early days, they refined it somewhat with changes internally, but they still require a lot of prep work on the chassis to cope .

You will notice that the firing order looks different from the Oakland-Pontiac of 1930-31-32 but is only different due to the cylinders being numbered differently than the Cosworth #1/2/3/4 on the left and 5/6/7/8 being on the right.
Oakland-Pontiac #1/3/5/7 on the left and 2/4/6/8 on the right.
This is due to a statement by one of the designers stating that if you turned the engine upside down and counted the conrods and then numbered the cylinders in a like order the only way you could logically change the numbering of them is by putting the front right hand cylinder ahead of the front left hand cylinder. :clap:
So much for the connecting rod numbering!

It certainly is true now that the manufacturers have to use only the 90 degree block and can’t mess around with the ridiculous Vee angles they were using on the V-10s. It would be very interesting to know just how much work went on at Ferrari and Renault to make sure the engines finished the races and just how they checked the cars to prevent the cars hitting the same frequency as the engine shake. On some of the old V-8s the problem was in the gears/pinions and the electrics rather than the main portions of the engines such as the rods, cranks and pistons. But just how much the material used on the tubs is sensitive to vibration is unknown by me.
M.L. Anderson