valve clearance

[Garrick Clark]

Hi guys,just done a top end rebuild on a 1914 engine.engine had various top end  problems,anyway just set the valve clearances and found a problem.on setting number 3 valve clearance the zero clearance way with the push rods spinning,when i rotate the engine clockwise 180 (BDC) ready to set number 2 clearances the number 3 inlet valve now has .008 clearance.I think it could be a follower or cam lobe problem.cheers for any replies to this

[Mike Lawless]

Most likely it is simply cam flex.

[Airspeed]

Most likely it is simply cam flex.

Just from 'stationairy' spring pressure turning the cam by hand?

I have noticed what you experience also, whether webcam, engle or EMW and already when new...
If your setting valve clearence when the lifter is at the opposite side of the lobe and your experiencing this, basically it means the base circle of the cam isn't exactly in the middle of the centerbore of the cam... or its indeed cam flex as Mike says?

[Garrick Clark]

Hi guys,I'm going to strip this unknown build quality bottom end and have a look.I'm just not happy with the way the valve clearance increases as the engine rotates,the valve clearance shouldn't be increasing like it is.if i set the clearances at say .004 at  TDC for any of the 4 cylinders that should be the biggest clearance number i get in 1 full revolution.I'll report back if i find anything.

Thanks for the replies

[Airspeed]

If i set the clearances at say .004 at  TDC for any of the 4 cylinders that should be the biggest clearance number i get in 1 full revolution.

Not neccesarily: Long duration cams are not set clearance by putting the cylinder at TDC. Thats for stock cammed engines...
You just may have one of those 'sporty' cams in there 

[jaqo]

valve clearance shouldn't be increasing like it is.if i set the clearances at say .004 at  TDC for any of the 4 cylinders that should be the biggest clearance number i get in 1 full revolution.

I adjusted many different, new and used, aftermarket cams and all of them did that.

[richie]

valve clearance shouldn't be increasing like it is.if i set the clearances at say .004 at  TDC for any of the 4 cylinders that should be the biggest clearance number i get in 1 full revolution.

I adjusted many different, new and used, aftermarket cams and all of them did that.

Me too,and I have never worried about it,if its set at zero at TDC,lifts what it should still at full lift then for me it is good


cheers richie

[Garrick Clark]

Ok cheers guys.Right well av split this unknown qualility bottom end down.Good Job Really.Cant say that i found any cam related problems,looks like a new cam kit.but the oil hole in the  bearing behind the front pully is bunged up with swarf,also bolted the case halves back together,cant see any day light between the saddles but the saddle behind the pully is bad.on 1 and 2 case half theres a good crush fit.On number 3 and 4 case half the bearing drops in and wiggles about.gunna get the crank looked at to as when i drop just the crank in the case with just a couple of bearings installed, and torque the main 6 its going tight.  wtf