So,

Has anyone put a lot of work into the a10? A member of this forum told me he built a 10,000RPM a10 with a round port head! The engine has such a short stroke I can only imagine it would rev like mad with some work. Maybe quicker revving than the larger a series engines, and a 1000 doesn't really need torque anyway.
Twin carb, oval port, lightweight pushrods, double valve springs, forged or motorbike pistons, anyone done it?

3 mains and semi counterweighted crank is not going to live at 10,000rpm. If you want big revs, A12 is the pick of the bunch

I would have thought less bearings less friction for RPM. Perhaps more vibration.

Quote:They may not last long, but they can do.

Saying it don't make it true. Add it to the 200bhp A15, also claimed by an ex-Nissan works mechanic btw ;), that was slower than my car in a straight line despite mine only having 3/4 the power in a 200kg heavier car. I know another racer up here claiming 240rwbhp from his Sports 2000 (original motor), unfortunately it struggles to pass Hyundai Excels down the straights...

I know this site is very fond of the 10,000rpm myth, but even the TS Cup cars - the most highly developed A series power plants on the face of the planet with much better fully counterweighted 5 main internals did not rev that high. There is simply no way this crappy crank will take 10,000rpm for even the length of a single rally.



Glad you mentioned Steve Newing. Here's some actual information about his engine:
Quote:

ie Steve Newing's own Sport Sedan motor, arguably the best A series engine in the country, made significantly less bhp/litre than what someone on the interwebs claims he said a classic rally A10 engine makes!!! Credible?

Another 2c.. Building an A series that can rev to 10k without falling apart is a much different proposition to building one that makes power at 10k.

Eg, My A12 has done over 10,000 rpm. Does that make it a 10,000 RPM engine?? Probably more embarrassing than impressive, as it happened when wrong slotting during a down change!!

I'd rather have an A12 that makes 109Hp at 8500 than an A10 that makes 109Hp at 10,000. Much less stress on the valve train and main bearings. You wouldn't have to run very thin rings to prevent ring flutter either. Less valve spring requirement takes the load off the cam lobes as well.

Although the A12 would make more torque, Both cars would be just as fast, as the higher reving A10 powered car could run a lower diff ratio to get the torque back at the tire patch.
The A12 would just last a lot longer, be a lot cheaper to build and maintain.

A12 and up all the waY but id rather an engine that does the hp at lower rpms say 7k max with usually means boost or content with lower expectations.

ALL A10s needed revvs to get any real hp as the 59mm stroke is more like a bike engine and treated as such. Steve built his engine for reliability and torque, he told me he could get 180hp but suffered more wear after tear down periods.

Dobeys dyno was an analog and surely unreliable setup, I believe he made 105-115hp from 10k rpm and for classic rallye it would be enough for the fun factor, Gordon used H89 heads with very nice work done to them and up. Very similar setup to the formula atlantic versions but needed rpm to flow enough.

The model T ford guys use a unitary laddder brace to hold the extra 2 bearings using later 5 bearing cranks. Expensive and only worth it if limited to A10 oringinal block and competing in a 1300cc class using a better A12 crank.

Either way no other reason to use an A10 except originality.

There are vids of a supposed A15 with 200hp but its still a unicorn for NA figures

I think the answer is something called Dyno Flash. People take the highest reading, not waiting for the dyno to stabilise. A friend had this happen with his open wheeler. The needle flashed to 250 HP then stabilized back to 200 HP, as he expected. An onlooker spread the word about the 250 HP figure, leading to a lot of bullshit & innuendo. Even the dyno operator agreed it only had 200 HP. Many a 500HP V8 has lost 100 HP on another dyno. Plus there's the old manufacturer's trick of not running any accessories or power sapping bits, for a bit of extra currency in their advertising.

I think dyno's are a rough estimate, not an absolute. The fastest datsun I had ever been in was a rally 1600 with a 1800 bored out to 1910 with twin 40's with all 240K running gear with big bucks spent and built by Gordan Dobie. Use to pump FJ's , strokers etc. Yeah he had the reputation as the Guru with all those records he held but as soon as I hear that name now, Gordon Dobie, I get nasty flashbacks from over 25 yrs ago. The guy was a bragger and took credit and large wads of cash for other peoples work. Constantly on the phone or talking in person to a guy called Steve ( Drove a sick orange 240Z )comparing notes and bragging. The bloke from Head Works did all Gordons heads and all machining was done by Motor Improvements back when it was on St Kilda Rd. And His dyno wasnt worth a pinch of crap and was way out ( told by a few people including his apprentice). I agree with D when stated all Gordons high reving motors spend more time out of the car and in. Nothing that rev's to 10K lasts without constant maintaining. When Gordon closed down (Beach Rd) in 90-91 , he was getting harassed by 3 un happy Fairlady owners not including myself. They were claiming they paid for 230 bhp motors and getting a lot less in their fairlady's. Gordan was producing dyno sheets that they said were something like 50 hp out. In 1989, $4000 and 11 mths later I got 31 bhp / 51?? hp @ 6000 rpm roughly cause wouldnt rev any harder without backfiring (dyno done by Chev Off Road) not 166 hp @ 8700 rpm as Gordon claimed on his dyno from my A14. The engine would rev fine but put in 1st under load it would just die. Which is impossible considering a gentleman by the name of Murry Carter from Highett spent half a day and returned my car running perfect. I must admit, I felt sick when I saw him tune my carbs with a bit of garden hose dangling from his ear, but it worked. I never had it dynoed but would estimate maybe 70 bhp - 80 bhp. Murry told me that the Cam was good upto 7500rpm was never dialed in and way out on the dizzy and flooding due to way too much fuel pressure. But at the end of the day , you can go to 3 different dyno's and get 3 very different readings, Suspension is just as important as Hp as well as gearing and that is why alot of bigger hp engines loose the race to smaller ones