Brabham BT 15 F3 - advice needed

[Robert_R]

Peter,

of course we won't find two people with exactly the same meaning regarding the most desirable or sensible form of historic motorsport. Especially when one practices one class, the other a different one. And without doubt each of the 3 classes we are discussing (although F3 seems to be "out of the race" for most of you) has its advantages and its disadvantages.

But I appreciate the various points of view a lot, and try to pull out the best for me, in order to make up my mind.

I will try to talk with the Envoy owner this weekend.

Mentioning the back tax, I absolutely didn't want to show-off. Actually it is the back tax for 2004, plus the deficit of the too-low advance payments for 2005 and the first quarter of 2006. This adds up to a crazy sum, which I didn't expect. My fault, of course. Again, I didn't want to sound like a boaster. It was just that I thought I had some spare money for a "boys toy", and now it's no longer as much as I thought.

In the meantime, I will keep looking for various cars on offer, and in any case I will stick to an early, cigar-shaped, tube frame car. Philippe also kindly provided some hints on interesting cars for sale. I will let you know how things are going on!

[PeterMorley]

Originally Posted by Robert_R

Mentioning the back tax, I absolutely didn't want to show-off. Actually it is the back tax for 2004, plus the deficit of the too-low advance payments for 2005 and the first quarter of 2006. This adds up to a crazy sum, which I didn't expect. My fault, of course. Again, I didn't want to sound like a boaster. It was just that I thought I had some spare money for a "boys toy", and now it's no longer as much as I thought.

In the meantime, I will keep looking for various cars on offer, and in any case I will stick to an early, cigar-shaped, tube frame car. Philippe also kindly provided some hints on interesting cars for sale. I will let you know how things are going on!

Don't worry, I know what you mean - whenever you think you have some spare money to spend on toys someone else comes along and takes it from you.
If I am lucky it is an engine builder or similar doing work on one of my cars, or more likely something like the girlfriend decides the house needs finishing (that is where this years budget has just gone)!!
And you can always rely on people like tax, insurance etc to hit you with a bill at the worst possible moment.

With any car only buy something you like - in this case cigar shaped, space-frame - if you buy something you don't like then you will probably end up being stuck with it (everyone else will suddenly agree with your opinion of it!) and you will be far less inclined to sort it out when something goes wrong (which it will if you don't like the car!) so it becomes even less popular.
That way the worst thing that happens is you just have to sit and look at it - some recent Ferrari F1s have been sold to silicone valley where they sit in the living rooms of various wealthy computer nerds, who don't even considered the possibility of driving them.

Philippe knows a lot of interesting cars for sale and the people who can help you with running them.

[Robert_R]

Originally Posted by PeterMorley

With any car only buy something you like - in this case cigar shaped, space-frame - if you buy something you don't like then you will probably end up being stuck with it (everyone else will suddenly agree with your opinion of it!) and you will be far less inclined to sort it out when something goes wrong (which it will if you don't like the car!) so it becomes even less popular.
That way the worst thing that happens is you just have to sit and look at it - some recent Ferrari F1s have been sold to silicone valley where they sit in the living rooms of various wealthy computer nerds, who don't even considered the possibility of driving them.

I will keep that in mind. But due to my concentration on the appeal of the car, which has to please me, I hope that in the worst case I will end up with a race which will be impossible to sell, but at least be beautiful to look at!

In the meantime I have talked to the Envoy owner. He will send me some more details and photos via Mail. He told me the reason why his car is offered so "cheap" is that the crankshaft of the engine is a "foundry" type (sorry, I don't know the proper english terms here), which is only capable to stand 7000 revs per minute, while the more solid "blacksmithed" type can be revved up to 10000. I hope you understand what you mean. Hmmmm...

[phdm]

Don't even try to rev an original Anglia hollow crankshaft in cast iron to 7k.

[Neptune]

"Don't even try to rev an original Anglia hollow crankshaft in cast iron to 7k."

I'm sorry but you've now asked for my 2 cents worth. I sure would love to have a steel crank, but my 997cc motor in my FJr has one of the solid iron 105E "service cranks". I've polished out the casting marks and any other marks except for the ID numbers. Then it was nitrided and shot peened. It's been in my car for about 10 weekends. The tach telltale is sitting at 8500 from it's last race. I try to keep it to 8K, but the A6 cam just wants to keep going. Forged pistons and steel rods make me feel safe. I've got another of these motors going together on the bench, a 1060cc version, but same spec crank.

I've got at least a half dozen of the hollow ones, some beautiully worked over. They came out of old engines bought for Cosworth parts. I don't care to try them but, Cosworth put one in every one of the Mk4 engines. They may have also used them in the Mk11 version too. The Mk4 FJr engines were standard in lots of cars of the day and they also used original 105E rods. Only reason it worked was such a tiny short stroke. Lots of these engines weren't even drysumped in their day. We're all so much more conservative today.

[PeterMorley]

Originally Posted by Robert_R

I will keep that in mind. But due to my concentration on the appeal of the car, which has to please me, I hope that in the worst case I will end up with a race which will be impossible to sell, but at least be beautiful to look at!

In the meantime I have talked to the Envoy owner. He will send me some more details and photos via Mail. He told me the reason why his car is offered so "cheap" is that the crankshaft of the engine is a "foundry" type (sorry, I don't know the proper english terms here), which is only capable to stand 7000 revs per minute, while the more solid "blacksmithed" type can be revved up to 10000. I hope you understand what you mean. Hmmmm...

I hope the Envoy looks nice then you could be happy.

I know what he means about the crankshaft - it is cast (in iron), that means it is an original Ford one (as Neptune says, with correct preparation, that is what Cosworth used originally and as with any engine if you use it within the limits given by the engine builder it will be OK).

Better than a cast iron crankshaft is a steel one (cost about 1200 pounds) that is what was used in the F3 engines - because they did 10,000 rpm, of course most Juniors now use them and can do higher revs than original.

There are 2 types of cast iron crankshaft - the very early one was hollow (to make it lighter), later there was a solid one. As Neptune says the solid one is OK for 8,000 rpm (or more) if it has been well prepared - it is very unlikely that this crank is hollow.

The fact that the engine has such a short stroke means the loading on the crankshaft is not so high. A steel crankshaft is even less likely to break, but the iron one is not a fragile thing.

Of all my Junior engines I only ever had one that had a steel crankshaft, the others had solid cast iron cranks and never gave problems when used at around 8,000 rpm.

Having the car with such an engine is not a bad thing, you can start with this engine and later on have it rebuilt with steel crank etc when you start to go faster etc. It should be a lot cheaper to upgrade the engine than to build a completely new engine.

(By the way in comparison to FFords - they all have cast crankshafts, they are not allowed such luxuries as steel ones).

[Robert_R]

Since I have the audience of some experts, here's another question:

I have noticed that some adverts (like the BT 15 in Sweden) mention that "...All rods and wishbones have then been cromeplated". Maybe I am wrong, but I believe to have read somewhere that chromeplating of suspension parts is not a good idea. The hydrogen used in the process becomes incorporated in the
metal somehow, making it very weak or brittle.

Is that right, or would chromeplated suspension parts be o.k.?

[PeterMorley]

Originally Posted by Robert_R

Since I have the audience of some experts, here's another question:

I have noticed that some adverts (like the BT 15 in Sweden) mention that "...All rods and wishbones have then been cromeplated". Maybe I am wrong, but I believe to have read somewhere that chromeplating of suspension parts is not a good idea. The hydrogen used in the process becomes incorporated in the
metal somehow, making it very weak or brittle.

Is that right, or would chromeplated suspension parts be o.k.?

I won't claim to be an expert just someone who has had a bit of experience with this kind of car.

In theory chrome plating does affect the steel (hydrogen embrittlement I think is the term for the process you describe). But I think that there are techniques to reduce this effect anyway.

By the 70's when suspension loadings were getting much higher they banned chrome suspension - apart from the chemical effect of chroming it is also harder to check for cracks in chromed components.

But in the 60's most suspension was chromed and most cars have it chromed when they are restored - and it works OK (as it did when it was new).

Even late 60's 3 litre F1 cars used chrome suspension and they have much higher loadings (bigger wheels, more power) than the earlier cars.

There are 2 other problems with chroming - when they polish it before chroming they can take away a lot of the weld, and sometimes they drill a hole in the tubes to allow the acids to escape.
Neither of these are good ideas - but they don't really cause problems either!

The only wishbone I had fail (on a Lotus 23) failed at the welded joint, but the driver did insist on climbing right up on all the kerbs which the car wasn't really designed for (it probably failed because the suspension tried to go well beyond the limit of its movement - so it would have failed anyway)!

If the person chroming it is good then there should be no problem, I wouldn't worry about it (especially if you are bothered about the cars looks)!

[Robert_R]

Hi guys,

although everyone suggested to go for anything else but a Formula 3, I wanted at least to see this little BT15 in Sweden. So I have examined the car on the Easter weekend.

Of course the car looked nice, as I had expected from the owner's pictures.

There were some things about he car which kept my wondering, so here are my notes:


The nose part of the fiberglass body shell had some cracks in the surface, probably due to vibrations. On the inner side of the cover no cracks or damage could be found in the fiberglass. So I imagine that just the surface (filler, paint) is cracked. But to have it nice again, it has to be resprayed.

The owner had warmed up the coolant with an electrical heater, attached to an engine water hose. Before starting, he has removed the plugs and has turned the engine with a kind of electric driller, in oder to build up oil pressure. The engine ran fine, no white smoke from the exhaust.

The gears could be engaged rolling the car forward and back a bit. With a gear engaged and the car jacked up, turning one rear wheel made the other one rotate in the opposite direction, so the differential seems to be o.k.

The gears could also be engaged with the engine running and the rear of the car being jacked up. Except for the reverse gear! The owner told me that he has taken out the gearchange fork (sp?) for the reverse gear, because he found the reverse gear useless and too dangerous to use. Hmmmm... funny, if he didn't want to use reverse, he simply could avoid to use it. Anyway, he showed me the fork and promised that the respective ratio was still in the gearbox.

The final drive is 8:35. The owner told me that this is longer than normal (better suited for fast circuits/high speeds). Will that be a problem regarding driveability?

On the other hand he told me that during the engine rebuilt a "tamer" camshaft has been installed, with less peak power, but a wider useable power band.

It has a modified distributor without contacts (points). It's a standard distributor, looks like a Ford Fiesta item. The rotor only gives the impulse for a pointless electronic ignition. Will that comply to european rules for historic races?

The gas tank is aluminium, filled with safety foam. Will that comply to european rules for historic races?

The brake calipers are made of steel (golden in colour) - I guess they should be magnesium instead? Will that cause problems at scrutineering for an historic event? Due to standing still over the winter, one of the rear brakes was a bit tight, but bake pad could be pushed back. I think the brakes should be overhauled anyway, with new rubber seals etc.

The suspension ball joints (uniballs sp?) - the car has a LOT of them - seemd to be tight and in order, as far as I could control.

The seat belts are dated 1995, so they have to be exchanged.

The tires are sparsely used, but 10 years old. The wheels are the original wobbly web items, but have not been crack tested.

The exhaust silencer is from a motorbike. The owner says it will pass a 100 dB test, but not a 90 dB test (which is neccessary now in Sweden).

I have taken some pictures as well. Any opinions would be much appreciated.

Regards, Robert

[phdm]

Robert,

Some comments:

Cracks in the fibreglass:
This is quite usual. It can be repaired but might happen again elsewhere. More important is probably to check the weight of the bodywork. If it is the original one it might have been repaired many times with added coats of fibreglass, which make it heavier? remember, weight is the enemy. I would not bother about the cosmetic aspect in the first place. You should first spend your money making the car go well and setting it up to your own taste.

Differential:
LSDs are not allowed on these cars.

Reverse gear:
I would advise to have one.
If the selectors are properly set up you should have no gear selection problems.

CWP:
Is the gearbox a Mk6 ?
The CWP you mention looks like one that was used in the Mk6 box which would be the period box for the car and IMHO was initially of VW origin. I am not familiar with the ratio normally used in a 1 litre F3 but 8/35 seems very short indeed, probably one of the shortest you can find (together with the later 7/31). Overall gearing has to be adapted to the various circuits where you will race so this means adapting the gear ratios to suit (with longer gears). You would have to calculate this based on the top speed you require and circuit configuration. A small programme can be downloaded from the Hewland website.
Mk6 parts are getting scarce today and are for some of them not interchangeable with the later Mk8 and Mk9.
You can however find replacement CWP in the US (or ring & pinion as they would call it stateside) but it might have to be redrilled to suit the diff.

Camshaft:
What is the camshaft used. A6 ? IMHO, the A8 was the standard F3 cam in period. A tamer cam would mean less power and less revs but more driveability.

Electronic ignition:
Electronic ignition was available in 1965 but I am not sure it was fitted to 1 litre F3 engines in period.

Fuel tank:
An aluminium fuel tank with foam should be acceptable unless the series you are contemplating specifically requires a rubber fuel cell.

Callipers:
Original callipers would have been Girling ARs and NRs in aluminium and not magnesium. Cast iron callipers can be substituted but offer less heat dissipation. As a rule you can "downgrade" the materials used compared with what was used originally, but not the other way around. For example, if magnesium was used in period, alunimium can be used instead but not the contrary.

Seat belts:
To be replaced. The same probably applies to the fire extinguisher.

Silencer:
Check with the circuits where you want to race if there is a noise limit.

Tyres:
You will probably be happier using fresh rubber.

Send me the pics to my email address.


This soun

[PeterMorley]

Philippe has already covered most the issues, the only one I might disagree with is about the callipers - Juniors and F2 cars used alloy callipers (Girling AR & NR usually), but as with F.Fords it is likely that an F3 would have used cast iron (e.g. production car) callipers - chances are alloy callipers were an additional cost extra.

I've seen historic cars with all sorts of callipers (including recent Mercedes road car in iron and modern 4 piston in alloy), the paperwork only asks that the callipers are of the same type (e.g. hydraulic disc, with solid discs), so I can't imagine any problem about the callipers - and I suspect they will be period ones anyway.

There would be no real advantage to changing callipers (alloy ones are expensive and unlikely to offer a noticeable increase in performance), and it is quite likely that doing so could mean changing rear uprights and front calliper mounting plates, since the bolt spacing could be different.

Using a less powerful camshaft in a formula where power is already pretty limited could be very frustrating - but in some cases a less powerful engine (with more torque) can be faster (especially on modern stop/go circuits - in period a lot of F3 races were held on very long circuits where you were flat out for a long time, that is very rare these days).

The gearbox definitely needs a rebuild, there is no reason that you shouldn't be able to get reverse - especially on a 4 speed box - there is a spring & plunger that provides enough resistance to stop you accidentally selecting reverse.

As long as the ratios you fit reflect the axle ratio it doesn't really matter what it is, as long as suitable gears are available (you would need to find out, from other racers, what speeds they run at and then look up the appropriate ratios on the Hewland ratio chart).

Late juniors run electronic ignition, so I assume there is no problem using it (in fact it could be essential at the revs these engines run at).

You should always use new tyres - after a couple of years the tyres lose a lot of their grip and their characteristics can change so much that there is no point even 'learning' on old tyres.
A friend (who Philippe also knows) realised this after crashing his Lotus 23B following a rebuild, because he used the old tyres - a set of tyres is far cheaper than an accident.

It should be a nice car (my twin-cam powered one was great) the only problem is the lack of events (one reason for pushing Juniors is the huge number of events - even compared to FFords there are probably more events this side of the channel for Juniors than anything else, in England there are loads of events for FFords but far less over here).

In terms of driving there won't be a huge difference between any of these types (Juniors, Fords, F3s) of cars - they all have similar performance, it is only more recently when they moved onto wings & slicks that things start to change dramatically.
So it is really a question of what events you can run it in - if there is a German series you can run it in then I'd suggest making a nice (low) offer for the car!!).

Peter

[Robert_R]

Hello,

after all this time I think it's only fair to let everyone, who had helped me with his input, know the result of all the considerations.

I finally bought that BT15, despite of all your warnings! When I had the first serious run, I will let you know how it went. Right now I am in the process of sorting out some mechanical and safety issues to get the car track ready.

Thanks again for all your recommendations,

Robert

[Finn]

Best of Luck Robert,

I'm sure it will make a good car.

I had my first run in a screamer last weekend and I agree with most on here that it is a bit tricky to drive having been used to a Formula ford. I'm sure with a bit of practice it will become easier, well I hope so anyway!!

let me know how you get on

[John Turner]

Yes, indeed Robert, please keep us informed of progress! (I'm not very good at taking advice either )

[Finn]

There is now a european championship for F3 screames taking shape.

All it needs is a few more cars and a big race to really put it on the map.

If anyone is thinking of racing one please support this series.

Details can be found below.

http://www.f3historic.com/

thanks

[Robert_R]

Finn and John,

thanks for your encouraging words. Of course I will keep you informed about my progress. In the meantime, I have posted some pictures at www.r-design.net/bt15/

I am in contact with the french organizers of the F3 Historic Trophy since I got interested in this little BT15. They are very nice and friendly people, and already helped me a lot. Unfortunately they still don't manage to get enough cars for 'F3 only' races. So they have to share the grids with FF, FJ and the likes. When I have sorted out the car (and I have got used to driving it), I will gladly take part in the trophy races.

Robert

[Finn]

Hi Robert,

Car looks great, you must be well pleased.

Yes it's a shame that there aren't enough F3's to fill a full grid but I hope in time there will be more cars coming out and better support. When historic Formula Ford started in the UK they ran with Formula Juniors for a while, now there are over 40 cars registerd so there is hope yet.

I hope to be doing the UK rounds so maybe see you at some point

Best of Luck anyway

[phdm]

Originally Posted by Robert_R

Finn and John,

thanks for your encouraging words. Of course I will keep you informed about my progress. In the meantime, I have posted some pictures at www.r-design.net/bt15/

I am in contact with the french organizers of the F3 Historic Trophy since I got interested in this little BT15. They are very nice and friendly people, and already helped me a lot. Unfortunately they still don't manage to get enough cars for 'F3 only' races. So they have to share the grids with FF, FJ and the likes. When I have sorted out the car (and I have got used to driving it), I will gladly take part in the trophy races.

Robert

Who has checked your engine finally ?

[allenbrown]

Robert

Which BT15 chassis have you bought? I noticed a chassis plate in one of the pictures but did you also get some history with the car?

Sorry if I've already asked you this question - I'm easily confused when it comes to BT15s!

Allen

[phdm]

Originally Posted by allenbrown

I'm easily confused when it comes to BT15s!

Allen

And what about when it comes to BT14s Allen ?

[allenbrown]

Good point. But I have the excuse that the BT14s are trying harder to confuse me.

[Robert_R]

Originally Posted by phdm

Who has checked your engine finally ?

Philippe,

I finally decided to have the engine checked over the winter. It sounded quite healthy, so I thought I could risk to do some test laps this year without doing too much harm, not at maximum revs, of course. I also took into account that the seller told me the engine had less than 3 hours running time.

Right now the carburettor is in a workshop in Cologne (VGS, Viktor Günter), for an examination/cleaning/rejetting.

And I have brought the gearbox to Mr Riegl last friday, so he can install a proper CWP (8/35) and an 'average' set of ratios for the start.

Regards,
Robert

[Robert_R]

Originally Posted by allenbrown

Robert

Which BT15 chassis have you bought? I noticed a chassis plate in one of the pictures but did you also get some history with the car?

Sorry if I've already asked you this question - I'm easily confused when it comes to BT15s!

Allen

Hi Allen,

it's F3-21-65. The only bits of history I have you will find in the BT15 thread in the Chassis History forum! Unfortunately the early history (ownership before 1969) is unknown, and I don't have a single race result for the car.

Best regards,
Robert

[R D P]

Sorry for bringing up this old topic again - but I am in a similar position as Robert at the moment ( Robert, I am friend from Peter H., I always wanted to call you, but misplaced your phone number ).
Actually I am torn between a Screamer and a Formula Junior...
I am flying over tomorrow looking at a Lotus 20, but still, in the back of my mind, I thoroughly like the idea to have a F3. FJ was planned since quite a long time, but after watching the Screamers live at Monaco I was deeply impressed.

What should I do ?
I still do thing that FJ is the more reasonable choice, more events to chose, a little bit less temperamental engines and more simplicity (on board battery, just one type of tyre). But I am not 100% convinced...
Any opinions are highly appreciated . thank you !

Ralf