pro mazda in fa

[Charles Warner]

Charles
Not to mention the BDR road version of the BD series. I can't find it just now but there was a big bore short stroke version just seen in england and used for hill climbs a BD???????? I think I will homologate a new one a BDTED.

Ted,

Regarding the BDR, my listing says "1983 1601cc 120 Bhp BDA Kits for Caterham Super Sevens, also 1.7 litre and 150-170 Bhp." Displacement problems if applied to atlantics?

While we are at it, my listing also shows a displacement of 1601cc for the BDA. Would this not exclude the "BDA" from the running? Even though any BD series engine is allowed it must be limited to 1600cc, no? The only BD series engines shown with 1600cc or less are the BDD, BDM, BDN, BDH & BDJ.

As far as a big bore/short stroke version in the BD series I only find the BDH (1300cc) and the BDJ (1098cc) as having a short stroke configuration. Doesn't mean there wasn't a local British version floating about.

The issue is being addressed and the suggestion has been put forth to adopt the engine rules as stated for the CSR in this instance. It would seem to be silly to apply the homologation issue to just one of the BD series engines. Just as silly as saying a BDA or BDR base can not be used as they came with 1601cc.

[Ted and Nancy]

Charles
All good points. Ref GCR FCS page 6 A.2.b the BDD does not fit as it was never in a FIA appendex J car only the original BDA was but that one was never homologated. Also look at FCS page 9 item 17 which I read as allowing max of 1615cc due to bore increase only. The BD came as a kit and as I remember you did not have to buy all of the parts as in blocks. I think your suggestion that the CSR rules would be the thing to do. I suggested that the comp board the FA and CSR have common rules for the VW-TOY-Cosworth as one of the original ideas for CSR was to use Ex FA Flat bottomed cars with bodys. Boy has that gone weird!!!!!!!!

[Paul LeCain]

I think the SCCA should be a little careful about allowing big-bore/short-stroke engines in FA.

The current Toyota will live for 500-800 miles using 10,400-10,600 RPM. That engine in a short-stroke version would likely live at 11,000-12,000 RPM. I have no idea for how long, but someone will do it if it's allowed.

That means that everyone who cares about being competitive will also have to start building and using these engines.

[dereklola]

Was it ever actually 1601? I've never check the actual or reported bore and stoke but I always thought it was just an homolgation trick to get it into a different class. Sort of 'rounded up' rather instead 'rounded down'. Anyone have the actual bore/stroke for the std Kent 1600 pushrod, the original BDA and the various BD? derivatives? I'd bet 25c they're all the same.

[Brian]

In the Cosworth book they do mention that the BDA was spec'd at 1601 to make it appear different from the pushrod motor. All they did was apply normal production tolerances to the bore and stroke to come up with a different number. The actual bore and stroke were identical

Brian

[Ted and Nancy]

The only engine on the list that does not have a "true" homoligated bore and stroke is the "BD series" . We have abou t 3 to 4 years experience with that motor and it lives between 11000 and 12000 and has about the same life as a pro Toy. Keep in mind that even at that RPM the piston speed is not bad. The limit seems to be rings and pistons. As you may have noticed there is no inlet restriction on the BD. When was the last time you witnessed a BD series winning any thing. The basic engine design is more than 30 years old and many are still out there and should be incoureged to come out and play. I feel that the free bore and stroke, no inlet restriction is the correct move to get this engine back on the track. If it dominates then give it 42mm chokes, but nobody needs worry just now. Look how that worked on the Mazda in FA and CSR it killed them!. We need to encourage more race cars to come out and not discorage this.

[Steve Jennings]

Paul LeCain: What bore and stroke would work best for the 4Ag Toyota in SCCA club racing if it were allowed and why would it be limited to only 12,000 rpm? There were several Honda bike engines that lived at 18,000 rpm 20 years ago so the technology is available and old. And, would you use a Honda rod bearing instead of the TRD unit ?

Steve Jennings

[Paul LeCain]

Steve:

I'm sure you're right that the rev limit could be higher than 12,000. My point was, that whatever the next limitation (valve springs, rod bearings, whatever) turns out to be, it will be more expensive for everyone, in more ways than just engine costs.

The most common transmission in FA these days is the Staff's. It's a reasonable unit, but it's nearing it's limits at 260HP. With more revs, shorter gears, etc., it will likely start to fail more often.

[Ted and Nancy]

Paul
With the CSR and FA we have been running the Staffs/MK5 for several years with no trouble at between 11000 and 12000. We installed a FT200 ring and pinion in the staffs so that we could get a lower gear (7-31) Transmission life has not been affected. It is not just the bore and stroke but the complete package that gives good engine life.