new 20v build aggressive cam, weird idling sound

AlpineFD
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new 20v build aggressive cam, weird idling sound

Postby AlpineFD » Fri Mar 03, 2017 7:37 pm

finally got my 4age 20v engine done, but while the engine is idling, we are noticing some rather odd sounds, is this normal with the aggressive cam?
any suggestions guys?

here's the video while idling
https://youtu.be/A32Uy_pC5as

the engine is a 4age 20v blacktop, stock bottomend, cby ported head, kelford type-c cam, toda cam gears, trd head gasket, new timing belt, mrp mechanical tensioner

jdm86gtz
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Location: Ireland

Re: new 20v build aggressive cam, weird idling sound

Postby jdm86gtz » Sat Mar 04, 2017 5:06 am

What did you set the valve clearances to?

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oldeskewltoy
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Re: new 20v build aggressive cam, weird idling sound

Postby oldeskewltoy » Sat Mar 04, 2017 10:53 am

Did you check piston to valve clearance?

Did you check piston to head clearance (squish)?
OST Cyl head porting, - viewtopic.php?f=22&t=300

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AlpineFD
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Re: new 20v build aggressive cam, weird idling sound

Postby AlpineFD » Sat Mar 04, 2017 7:01 pm

that's the next thing the shop will check the piston to valve clearance and head clearance.

but I like to think the cam was properly shimmed and degreed in according to the kelford spec sheet.
assuming that's the case, and the fact that the noise frequency is quite rapid, seem to indicate it's something todo or connected with the valve movement.

What other possibilities could there be?

I'm using a VVT Delete from SQ Engineering and a high pressure spring for the oilpump (from sq), not sure if these are connected?
what about the distributor? (removed the distributor cap, replaced with a sq cap, and using coil on plug with haltech controlling it) and a good basemap.

I already tried moving ignition at idle 5degree both ways, didn't help.

AlpineFD
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Joined: Thu Jan 10, 2013 9:59 pm

Re: new 20v build aggressive cam, weird idling sound

Postby AlpineFD » Tue Mar 07, 2017 4:52 pm

false alarm, it was just the timing belt touching a loose front lower cover =)