A10 camshaft

[Acidvalley]

Hi,

Today I stripped the engine of my A10 (plunger)  'Golden Flash'. Sadley, It needs boring , big ends are weared out and camshaft is seriously damaged. Pretty messed up after 25 years driving without major problems and almost no maintenance    Most certainly the camshaft needs to be replaced. I want to put a 'hotter' camshaft in to increase power. Can anyone give me advise witch camshaft I can use (it's not for racing purpose).

Ps: the cylinderhead is NOT aluminum-alloy but old good steel

Cheers ,

Tom

[a10 gf]

Hello, and welcome to the forum. Just a few toughts,

after 25 years driving without major problems and almost no maintenance

... this is the result of not taking out more power than the parts are dimensioned to bear over with, combined with a good rider (and some luck!).
If you increase power, chances are reliability goes down, and all sorts of problems may arise, the carb may need rejetting, idle problems, wear on critical parts may rise drastically, brakes are not up to the job etc,  so IMO stick to original configuration (and get a second bike for harvesting speed tickets  ). My opinions only.

btw unless totally worn down or bent, cam can be refaced, together with cam followers. Check with SRM or any other well renowned machine shop.

Regards
E.

[fido]

Cams and followers do tend to wear on the A7/10. It may be worth investigating the various wear resistant treatments such as titanium carbide coating, nitriding etc.

[Acidvalley]

Hello ,

If you increase power, chances are reliability goes down, and all sorts of problems may arise, the carb may need rejetting, idle problems, wear on critical parts may rise drastically, brakes are not up to the job etc,  so IMO stick to original configuration (and get a second bike for harvesting speed tickets  ). My opinions only.

Maybe it isn't a good idea at all tuning the bike,indeed . I think I'll leave the bike in the original configuration.

Thanx for advice !!

Tom

[dpaddock]

Acid, don't screw around! Get stock replacement parts and count your self lucky.

[Acidvalley]

I am a very lucky man !! I have a wonderful wife , 2 lovely children , a Laverda SF 750 and my BSA A10  The BSA needs rework after 25 years of duty. The rest is a daily job 

BTW: I stay with the A10's original configuration .

Acid

[Acidvalley]

Today I went to a spares-shop for new pistons , valves , bearings , primary chain , front and rear cam and chain , new camshaft , and some other small stuff. 847 euro , I'm broke now    The seller was astonished about the camshaft that came out of my A10 (1953) . It's one from a super rocket , the 'hottest camshaft' available for the A10     ???? He had never seen that in combination with a iron cilinderhead.  He advised me a camshaft from a rocket witch should be flatter but still hotter than the original. Any opinion someone ?

Greetz,
Tom

[a10 gf]

Hey, lots of good work you are doing! I am no camshaft expert at all, and always play safe with old machinery. But since you write you had a SR cam and the bike performed well (and long), then there should be no harm in trying out the suggestion from your parts dealer. How long it all lasts depends as much on your riding style and maintenance (good oil pressure, correct carb jetting at all rpm, ignition spot on) as the tuning of the engine.

You have a thin bottom flange cylinder (original)? If so it is not the ideal partner for too much power (the cylinder may one day make an attempt to leave the rest of the engine behind). But maybe the cyl was changed once upon the time, together with the cam. If you have the thick flange cyl you are on safer grounds for extracting some more hp's, and may even take the chance of upping the compression a little. Not any recommandations, just mentionning possibilities. Post some picture if you find the time.

Regards
E.

[dpaddock]

The -357 cam from the Super Rocket/Spitfire/RGS is NOT the cam you want. Unless you are willing to do severe port modifications, valve enlargement, stiffer springs, etc. And then live with valve clatter and accelerated valve train wear.
May I suggest you return the -357 and fit the -356 cam? This will give you some added pep without the foregoing unpleasantries.

[Brian]

dpaddock is right, use the 356. A carefully assembled and tuned standard motor will nine times out of ten out perform a so called hotted up one and you have a sweeter more reliable engine.

[Acidvalley]

I bought the 356. The 357 came out and was pretty f*cked-up  If I've the time I post some pics.
The strange thing is that the engine was running very smooth  The major problem was to get the engine running after a couple of days not running.  I had to put some gas into the cilinders and heat up the sparkplugs with a flamethrower  and then he was going like hell   just until he died  RIP
It doesn't have an alloy head and , I suppose , not modified ports - valves - springs , the cilinders have had new liners (don't know liner is correct ? ) 

Last week thursday I brought the engine to the engineering shop . The Cilinderhead will be taken care of , boring , honing , a new bronze bus for the crankshaft and reconditioning of the crankshaft. The crankshaft-taps need a new layer of chrome since they said it needs  -40 shells. They said the taps are getting weak and soft  at -40 so rechroming should be better than original. One thing is for sure : The bill will be not pleasant  But I'm looking forward to the result

Greets,
Tom

[dpaddock]

"Liners" are not fitted to the barrel; the bores are machined in the barrel material which is cast iron.
What are "taps"?
Try to fit a factory timing-side bush, not a substitute.
After all is done, be scrupulously vigilant and change engine oil often; 1000 miles is not too often.

[Acidvalley]

By taps I mean the place where the big-end bearings  the crankshaft.

- I was told that the bronze timing-side bush was not available so it needs to be manufactured by the engineeringshop. Why should this be not OK ? I know this is a critical piece in the A10's engine but I suppose if the bush is well manufactured there will be no problem. Correct me if  I wrong on this ?

- Where can I find an oilpump for a good price ?  UK's SRM oilpumps are very expensive (+- £217 + VAT). Does the oilpump needs to be replaced anyway ? And what about the oilpressure-valve ?

Tom

[fido]

The oil pump can be dismantled for inspection. It should be fairly stiff to turn, if you can spin the spindle it is too worn. It is possible to surface grind the joint faces slightly to remove wear.

[dpaddock]

Contact C&D Autos at canddautos@eidosnet.co.uk, in Henley-in-Arden. They should have the timing side bush you need, plus the oil pump. The bush MUST be manufactured and installed properly. Follow BSA Service Manual instructions faithfully.
Don't snivel about the prices - factory stock is depleted, so thank those good folks who take the time, effort and risk to provide us with on-going repro spares.
If you don't know how to assess the oil pump, replace it. It's critical!  Use BSA Service Sheet No. 215 to reassemble and fit the pump.
The oil pressure valve is not a wear item. Just make sure it's clean and that the spring has a nominal free length of 5/8-inch.
Make certain the oil retaining ball (item 105, plus 104 and 103, Plate 2 in the Spares Manual) is free to do its job.
Tom, please do the fine job your fine BSA needs.
David