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Cam
Home away from home
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2009/10/13 21:28
From Trinidad and tobago
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I have a A15 engine,and i want to change the cam maybe hotter?For street.can i go to the local shop here an purchase 1,what do i need to ask for.Because i have little cash and will be hard to buy overseas.

thanks..

Posted on: 2012/11/16 19:24
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'71 Four Door Sedan.
A15 Engine + Lighten Flywheel.
E15 Electronic Ignition 32/36 Weber EI Coil 4 into 2 into 1 Extractors 1 3/4 Exhaust Pipe Semi Flow Hotdog 60 series Gearbox H150 Diff.

Street Sleeper!

STILL LIVIN' THE 70'S LIFE !!
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Re: Cam
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From Hawaii, USA
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Put in the A14 camshaft, it will wake up the A15.

If you have a 1979-1980 A15 it has the good camshaft. If it pulls hard to 6000 RPM, you have the good one. If it falls off at 5000, it has the mild cam.

A15 1981-1982 North America-spec: Mild camshaft
A15 1983-up worldwide (Vanette): Mild camshaft
A15 industrial: very mild camshaft

In any case you can install a higher duration camshaft (more than A14) along with high-RPM springs and a larger carburetor (e.g. Datsun L20B carburetor). Then you can rev it higher than 6000 RPM to make more HP. At any shop, ask for a camshaft for A15 that works in the RPM range you desire. Some local shops will know what to do (they are used to ordering custom cams from a camshaft vendor). Other shops won't know what to do.

datsa73 here was selling an A15 camshaft with power band where you shift at 8500 RPM. This requires a GX cylinder head or a competition-ported oval port head.

New they cost about $100 in USA. They are custom ordered, not listed in a catalog. You also need new springs (another $100) and should get new lifters (another $100)

Posted on: 2012/11/16 20:30
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Re: Cam
Just can't stay away
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2012/8/29 23:21
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Do you have to run Dual valve spring with a better than stock cam?
Or can you get away with stock valve springs?

Posted on: 2012/11/17 3:42
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Mahalo Victor
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Re: Cam
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What is "better than stock"? The stock camshaft is very very good for 3000-6000 powerband. It came in 1975-1980 A14/A15.

Do you need them? With extra high RPM cam you will need upgraded springs. Either single or dual. Sometime you need special springs with low-RPM high-lift cam, so ask you cam vendor.

If you rev the engine higher than 6000 you should get special hi-rpm valvesprings. The stock ones will usually go 6400 RPM but they are not engineered for it and at 40 years old may not even go to spec. Try it, if it runs smooth they are OK.

Nissan sold 6400 rpm dual-valve springs. Iskenderian sells dual springs for something like 9000 RPM, which springs should be avoided unless actually running the engine high RPM because they wear out the valve guides and cam lobes faster.

Posted on: 2012/11/17 3:55
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Re: Cam
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Most popular aftermarket cams are higher duration, they don't work as well until higher RPMs where they are superior.

Some cams are marketed as "RV" cams which are lower HP than stock, they are designed for lower RPM cruising and short shifting.

Beware that many cams purchased actually make less usable horsepower for the way people drive. So does the stock cam -- if you don't like to rev it up, you should replace it with a lower RPM cam so it makes more HP at the RPMs where you drive. Like a stock A12A cam would do in an A15. Which is what Datsun did in 1981.

Finally there are high-lift, quick-open cams which can improve HP at lower, mid and high speed without necessarily shifting the powerband into higher RPMs. These can be really agressive on roller cam engines -- far more than 1970s hot cams. Unfortunately A-series is not favorable for a roller cam (journals are too small). Even so, cam vendors can do some high-lift and quick-opening magic for A-series but they can be noiser and wear faster.

Call your cam vendor and ask for their advice. Tell them what RPM you will be running at and where you want to shift, and whether you care if the valvetrain last 5 years or 5 weeks. Iskenderian is a favorite custom grinder for Datsuns, but most any cam company will do it. You send in a spare or the original, they grind a new cam lobe pattern and send it back. For a really advanced cam they might need to weld it up to grind the profile on it. The extra dollars can be worth it.

Posted on: 2012/11/17 4:25
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