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0.05 - 0.38mm/0.002" - 0.015"


MikeS
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WIth the 70 now run in I thought I should check the tappets. ASP suggest a tappet cap of @.1mm, what happened to say something like 1mm or 2mm

Hmmm well call me old school but my feeler gauges are:

0.05 - 0.38mm or 0.002" - 0.015"

So does @.1m mean 0.1mm or 1mm

Help!!.

Mike

Edited By MikeS on 29/03/2013 08:34:51

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That'll be 0.1 mm then, about 4 thou in old money. They should have put in the leading zero so the decimal point does not get missed!

Even that sounds a bit big, many small motor bike engines have a gap down in the 0.05mm range. But if that's what they say...

Too big and you get more noise, valve train wear and less power. Two small and you get poor running and burnt valve seats. What can catch you out is if the gap is a bit small is that the engine may start ok but then stop with poor compression when it starts to warm up,This is because the exhaust valve stem has grown in the heat of the exhaust and completely taken up the tappet gap!

Shaunie.

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It means 0.1mm, which sounds about right. Much less and when the motor gets hot you run into the problem of expension and the gap may get small enough to the point the valve doesn't close properly. At 1mm it'll rattle like a bag of nails and won't run well at all.

4 to 5 thou should be fine. Alternatively go buy a metric set of feelers!

Ian

Ps. Just seen Shaunie's post. He's dead right.

Edited By Rentman on 29/03/2013 09:09:29

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Tappet clearance for ASP/SC/Magnum engines is recommended as 0.04mm and 0.10mm.

If you are used to setting valve clearances, use the 0.04mm feeler gauge. It should be a sliding fit between the rocker arm and the valve stem and should not need any force to move. Use light machine oil e.g. 3-in-one oil to lubricate the feeler gauge. Only do the setting at room temperature.

If you are only learning then use the 0.08mm gauge. Good luck thumbs up

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Posted by Shaunie on 29/03/2013 09:07:08:

That'll be 0.1 mm then, about 4 thou in old money. They should have put in the leading zero so the decimal point does not get missed!

Even that sounds a bit big, many small motor bike engines have a gap down in the 0.05mm range. But if that's what they say...

Too big and you get more noise, valve train wear and less power. Two small and you get poor running and burnt valve seats. What can catch you out is if the gap is a bit small is that the engine may start ok but then stop with poor compression when it starts to warm up,This is because the exhaust valve stem has grown in the heat of the exhaust and completely taken up the tappet gap!

Shaunie.

enlightened Oh so that's where the compression goes on my Saito then ! Enlightened, thanks.

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Right well it has been a while since I used to adjust tappets when I used to work at ford (in my teens) but the principle must be the same.

Well I have a 0.004 gauge so had a look the ASP 1.20 tappets. Pretty good gap there so undid the small nut and adjusted the small screw until the gauge blade would flex as I tried to slide it through.

Backed the screw off until the gauge slid thorough ever so slightly firmly but without flexing. Slowly turned over the engine and it all looked good.

Thanks everyone for the help.

Mike

Edited By MikeS on 31/03/2013 10:22:26

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Posted by ERIC CLAPHAM on 30/03/2013 09:16:28:

Read what Brian Winch has to say . If you dont know who BW is then you will be ever after the 8ball . Rgds.,Eric.C.

The WOO knows a great deal but I do have to disagree with him on some things. In one recent RCM&E he asserted that fuel will always remain at the rear of the tank, even on downlines, due to the forward motion of the aircraft. Can't see how that would be unless the aircraft was falling in a vacuum!

Some of his article on soldering was quite scary too!

So as with all things, apply your own commonsense filter.

Running for cover now!

0.04 to 0.1mm that's more like it although that's quite a big range, set the gap somewhere in the middle perhaps.

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Agree with you Shaunie. I didn't get the fuel tank thing either. If the tank is horizontal and there's no acceleration the fuel will lie evenly at the bottom of the tank. For the fuel to be elsewhere it needs a force of some sort ie. gravity, acceleration, deceleration. He did qualify some of his soldering stuff, also maybe H&E (that old chestnut) isn't as strictly applied in Oz. dont know

Otherwise WOO is a fount of useful information. A very well informed guy.

Ian

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