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Discussion and questions related to the course Engine Building Fundamentals
Hi I'm in the process of degreeing my camshafts, the engine i a 3SGTE, as some of you might know this engine has solid lifters that uses shims to adjust the valve clerance.
The question that I have is: are the valve lash/clerance suposed to be set to zero while degreeing the camshafts?
No matter what I'm doing I will allways be of on the vallues that I'm shooting for, by this I mean the valve lift i supposed to be EVO 1,00mm at 46BBDC and EVC at 2BTDC, I wil ALLWAYS either get 0,70mm @ 46BBDC and 1,00mm @ 2BTDC or 1,00mm @46BBDC and 0,70mm @2BTDC.
Note the error that I get is equivalent to the specified valve clerance that is 0,30mm for the exhaust valves.
Just as an expirement I tried to put a 0,30mm blade from a feeler gage between the cam and the lifter while turning the engine over so that the cam profile is riding on the feeler blade when pushing the valve down, this should be the equivalent to setting the valve clerance to zero.
The thing is when I do this I get exactly 1,00 mm @46BBDC and 1,00mm @2TDC just like my camcard says I should.
I've been looking around on the internet trying to find info on this but it seems that nobody ever wrote anyting on adjusting DOHC engines with solid valve lifters, all I could find is just V8 stuff and some Honda stuff.
Please feel free to tell me how you go about doing this on these types of engines as I'm having a hard time finding info on this.
Have you reviewed the factory service procedures? they are available here: http://manual.teq.org/
I attached the relevant PDF's for MR2 3SGTE. Tuneup.pdf is attached. Page 7 talks about adjusting valve lash. The timing belt and cylinder head procedures are also attached.
If you're dealing with a mechanical cam profile then the cam should be timed with the lash set to the recommendation on the cam card. What brand of cam are you using? I'd be inclined to discuss this with the manufacturer because it does sound like there's something odd with the specifications vs reality.
The numbers you've mentioned though don't quite add up. If the cam card was specified at zero lash (0.3 mm on the exhaust) I'd expect you to be seeing 0.7 mm at 46 deg BBDC and 2 deg BTDC where as you're seeing 1.00 and 0.70mm. Obviously there assuming the same lash on both intake and exhaust which won't be accurate but hopefully you get the picture?