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View Full Version : new 20v build aggressive cam, weird idling sound



AlpineFD
5th March 2017, 02:04 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, vvt delete plug (sq engineering), distributor cap replaced with sq cap, coil on plug, controlled by haltech with a good basemap.

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.

Slimer86
5th March 2017, 04:44 PM
Were the cams degree'd and timed correctly according to the cam card when installed? I agree that it sounds valve train related given the frequency. Only other thing I can think of is a super noisy injector (xspurt 1000cc are noisy) but not that noisy.

davew7
6th March 2017, 11:19 PM
It does sound like a valve train noise. Take a long screw driver and place it against your ear while touching the other end on different engine locations to see if you can pin point the area the noise is coming from. Dave W

LittleRedSpirit
7th March 2017, 08:51 AM
Dont run it pull it down and check your clearances and make sure.

AlpineFD
8th March 2017, 11:54 AM
false alarm, it was just the timing belt touching a loose front lower cover =)