Piston to Valve Clearance
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Road Captain
Joined: Aug 2018
Posts: 589
Likes: 93
From: Stockholm
With a 57, I wouldn't bother.. If you were running a 9B and a 2 inch intake valve, I would.
Got a caliper and straight edge? Measure the distance of the edge of both valves head gasket surface. Multiply that that distance by 0.866. See if its less than TDC lift.. If so the valve don't even break the plane of the head. I'd you end up with plenty clearance..
Heck the 57 will work with stock 103 pistons. It's a bolt in cam..
Got a caliper and straight edge? Measure the distance of the edge of both valves head gasket surface. Multiply that that distance by 0.866. See if its less than TDC lift.. If so the valve don't even break the plane of the head. I'd you end up with plenty clearance..
Heck the 57 will work with stock 103 pistons. It's a bolt in cam..
I have also mailed JE Pistons, but not received an answer yet.
Max, interesting method you described. Will maybe try it, but not sure I understand why multiply with 0.816. However I suppose it has to do with the angle between the plane of the piston surface and the plane of the movement of the valves, or? But should not then the TDC lift be multiplicated with 0.816, (not the measured distance), then subtracted from that measured distance. If the figure then is positive the valve will never reach the plane of the gaskets surface. Or..? (Just thinking loud here again. Never been a professor.) Anyway very interesting method, and thanks a lot for your input.
Last edited by OakMountainRider; Dec 19, 2024 at 09:35 PM.
Seasoned HDF Member
Joined: Dec 2005
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From: poway
Yes, it is a bolt in cam. Stock springs will work from 2007/Dyna 2006 and up, according to Andrews. Gary Wallace recommended the 57, upon he had been informed about relevant data, such as compression, deplacement, gasket thickness, milling if heads, pistons and so forth.
I have also mailed JE Pistons, but not received an answer yet.
Max, interesting method you described. Will maybe try it, but not sure I understand why multiply with 0.816. However I suppose it has to do with the angle between the plane of the piston surface and the plane of the movement of the valves, or? But should not then the TDC lift be multiplicated with 0.816, (not the measured distance), then subtracted from that measured distance. If the figure then is positive the valve will never reach the plane of the gaskets surface. Or..? (Just thinking loud here again. Never been a professor.) Anyway very interesting method, and thanks a lot for your input.
I have also mailed JE Pistons, but not received an answer yet.
Max, interesting method you described. Will maybe try it, but not sure I understand why multiply with 0.816. However I suppose it has to do with the angle between the plane of the piston surface and the plane of the movement of the valves, or? But should not then the TDC lift be multiplicated with 0.816, (not the measured distance), then subtracted from that measured distance. If the figure then is positive the valve will never reach the plane of the gaskets surface. Or..? (Just thinking loud here again. Never been a professor.) Anyway very interesting method, and thanks a lot for your input.
0.866 is the cosine of 30 degrees.. The approximate angle of the valve from straight up. You want the vertical travel.
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Road Captain
Joined: Aug 2018
Posts: 589
Likes: 93
From: Stockholm
Well, if I could find the Dyna 2006 stock head specifications and they were including the distance from the edge of the valves to the plane of the head gasket surface, then after calculating maybe I would be able too bolt in that cam without lifting the heads and without worries
Last edited by OakMountainRider; Dec 20, 2024 at 05:04 AM.
Seasoned HDF Member
Joined: Dec 2005
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From: poway
Ah, sorry, 0.866 I meant.
Well, if I could find the Dyna 2006 stock head specifications and they were including the distance from the edge of the valves to the plane of the head gasket surface, then after calculating maybe I would be able too bolt in that cam without lifting the heads and without worries
Well, if I could find the Dyna 2006 stock head specifications and they were including the distance from the edge of the valves to the plane of the head gasket surface, then after calculating maybe I would be able too bolt in that cam without lifting the heads and without worries
Thread Starter
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Road Captain
Joined: Aug 2018
Posts: 589
Likes: 93
From: Stockholm
No I have not touched them. Thing is, bike is at my work in the cellar. There is no ventilation there and I hate to empty that petrol tank. This is why I try to get around pulling the heads. Maybe someone can measure their heads. It is the same heads on dyna 2007 and maybe on more.
Below is enclosed:
1/ A drawing I made in IIlustrator
2/ A picture of my heads
I do not know the sizes of the valves, but I found a part number for the front head.
Heads are milled 0.010", so it is not much.
The only thing I need are the measurements where there are question marks. My thought is that someone here at the forum may have these heads (stock) on their shelf, and would be so kind to measure them.
Last edited by OakMountainRider; Dec 21, 2024 at 07:06 PM.
Banned
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A question regarding the above method, is it really certain that valve to piston interference happens exactly at TDC?
The piston moves relatively slow around TDC, with aggressive cam ramps the valves might move faster was my thought.
The piston moves relatively slow around TDC, with aggressive cam ramps the valves might move faster was my thought.
Seasoned HDF Member
Joined: Aug 2008
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that is true mr. sm
the issue is valve position at TDC. that is the point of closest contact since piston is at highest position.
remember, there always must be a fudge factor to account for float.
clay will give the best results for the poor man without the math.
also, all parts must play nice together, after all, it is a system.
the issue is valve position at TDC. that is the point of closest contact since piston is at highest position.
remember, there always must be a fudge factor to account for float.
clay will give the best results for the poor man without the math.
also, all parts must play nice together, after all, it is a system.
Thread Starter
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Road Captain
Joined: Aug 2018
Posts: 589
Likes: 93
From: Stockholm
Hello, another subject: Valve to valve clearance.
To my understanding there will be no problems with Andrews 57 and a Dyna 2006 head in this respect as valve to valve clearance is not affected by piston type, head gasket, milled heads etc and as Andrews recommends the cam to my bike.
If the heads are stock and no modifications are made to the heads/valves, there will be enough clearance. Am I correct in this assumption? Or should I have this checked as well?
I imagine there are many bikes with the same heads as I have, running with Andrews 57 without any valve to valve issues.
To my understanding there will be no problems with Andrews 57 and a Dyna 2006 head in this respect as valve to valve clearance is not affected by piston type, head gasket, milled heads etc and as Andrews recommends the cam to my bike.
If the heads are stock and no modifications are made to the heads/valves, there will be enough clearance. Am I correct in this assumption? Or should I have this checked as well?
I imagine there are many bikes with the same heads as I have, running with Andrews 57 without any valve to valve issues.
Last edited by OakMountainRider; Dec 30, 2024 at 12:55 PM.
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Seasoned HDF Member
Joined: Mar 2010
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From: Poolville
You'll be fine Just put it in set your pushrods properly and you should have no issues. You need to remember that when the MOCO sets these motors up there is literally 0.100" valve to Pistons clearance.. And valve to valve is negligible till you start sinking the valves in the head and really decreaseing the combustion chamber sizes and increasing the overlap and duration.. If you were to take 50 to 60 thousands off the cylinder heads then yeah you definitely want to check it but that ain't going to change your valve to valve..