OST-050 - a VERY special build
11-14-2018, 09:45 PM (This post was last modified: 11-14-2018 09:50 PM by oldeskewltoy.)
Post: #37
RE: OST-050 - a VERY special build
oldeskewltoy Wrote:the pulleys (BOTH) move about 1.5-2.0 degrees counter-clockwise. Another thought though would be to keep the pulleys stationary, and move the crankshaft clockwise to take up the slack.....

moving the crank clockwise 1.5-2 degrees to take up the slack means we have retarded cam timing. To confirm, we go back to the cam pulley, and visually rotate to correct... we move the cam toward the "A" to correct for machining


A LOT more to come... pretty soon..... Hurray!



Well, it is time to address this... because of the machine work, and the gasket, cam timing has been retarded about 1.5-2 degrees - I'll be rounding to 2 degrees.

Some may be asking why address this? For purposes of this build, the client wants a smooth idle - he does not want any lope. The engine should idle as if it just came off the assembly line. To do that we want the lobe separation angle "wider".

This works for Lobe Separation Angle (LSA): http://www.compcams.com/Pages/413/cam-ti...angle.aspx

If you would like to "play" with cam timing changes Tomei has an Excel sheet: http://www.tomei-p.co.jp/tool/valve_timing_graph_e.xls (look at idle quality chart @ bottom as it changes with centerline/LSA changes....)



Stock 4AGE cams use 111 degrees for their centerline. The Cat cams I'm using have a center line of 110 - one less. The machining has reduced that by 2 more, making the new centerlines/LSA @ 108 degrees.

108 degrees isn't a huge difference, but it may affect idle quality, and that is something I don't want.......


but how to adjust cam timing without adjustable timing pulleys????


more to come..... Hurray!

Dan -

You can |Sad .... OR you can ask for help!!!

OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991
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Messages In This Thread
OST-050 - a VERY special build - Bean - 07-05-2018, 10:07 PM
RE: OST-050 - a VERY special build - ditn - 07-09-2018, 02:06 PM
RE: OST-050 - a VERY special build - Bean - 07-09-2018, 03:11 PM
OST-050 - a VERY special build - Bean - 07-25-2018, 11:34 PM
OST-050 - a VERY special build - Bean - 09-19-2018, 06:26 PM
RE: OST-050 - a VERY special build - Bean - 09-19-2018, 11:40 PM
OST-050 - a VERY special build - d3nso - 09-21-2018, 08:11 AM
RE: OST-050 - a VERY special build - Bean - 09-21-2018, 10:15 AM
RE: OST-050 - a VERY special build - oldeskewltoy - 11-14-2018 09:45 PM
OST-050 - a VERY special build - Bean - 10-03-2018, 07:22 PM
OST-050 - a VERY special build - Bean - 10-17-2018, 09:18 PM
OST-050 - a VERY special build - Bean - 11-21-2018, 05:52 PM
OST-050 - a VERY special build - Bean - 12-06-2018, 09:50 AM
OST-050 - a VERY special build - Bean - 12-29-2018, 09:59 PM

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