Hi I have been sorting cams and adjusting pushrod lengths to suit as the exhaust valve has a 3mm higher stellite weld build-up than the inlet valve. This was causing the tappet screw to be adjusted out to a point where it was hardly protruding out of the adjuster and only holding by a few threads. Now that the tappet screw is midway through its adjustable length with tappet set at zero the spring binds every few revolutions. I have tried cams with less lift with same effect still every now and then turning over with the kick starter without a plug it goes off lie a rifle shot.
I have removed the inner spring and its solves the problem kicking it over but would it hurt to start the engine like this? I have run stationary engine with very light exhaust springs... No high comp pistons though. Just want to check a few other issues while I try and source some bee hive type springs.
Brian
ps if anyone knows a source of suitable springs in Australia?
Valve springs catching
- Brian_Walker
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Valve springs catching
1951-52 VCH under restoration
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Re: Valve springs catching
Brian
If you have valve bind, do not use those springs. It does sound like the inner spring is not correct. That said the VG/late VH spring will bounce and the early VH spring is too strong (from memory over 300lbs seat pressure) and becomes valve bound with higher lift cams.
I use LS2 Chev/Holden Commodore beehive springs. It is also possible to use the ecotech V6 Commodore spring which works well in the long stroke VH, but did give me problems in my shortstroke VH which was run up to 8000rpm. You can also purchase ovate conical aftermarket LS2 springs but may have to purchase 16 rather than the 2 that you need, dependant on the supplier.
With either the ecotech V6 or LS2 spring you will need to have top and bottom valve collars made to suit, although it is possible to use the LS2 or ecotech spring with the standard VG/late VH top collar as the reduced dia top of the beehive spring is a nice fit around the tapered section for the split retainers. The advantage of using std top collars is that the normal valve cramp will work whereas the smaller dia of the specific beehive top collar needs a different valve cramp. You will still need to have new bottom collars made.
David
If you have valve bind, do not use those springs. It does sound like the inner spring is not correct. That said the VG/late VH spring will bounce and the early VH spring is too strong (from memory over 300lbs seat pressure) and becomes valve bound with higher lift cams.
I use LS2 Chev/Holden Commodore beehive springs. It is also possible to use the ecotech V6 Commodore spring which works well in the long stroke VH, but did give me problems in my shortstroke VH which was run up to 8000rpm. You can also purchase ovate conical aftermarket LS2 springs but may have to purchase 16 rather than the 2 that you need, dependant on the supplier.
With either the ecotech V6 or LS2 spring you will need to have top and bottom valve collars made to suit, although it is possible to use the LS2 or ecotech spring with the standard VG/late VH top collar as the reduced dia top of the beehive spring is a nice fit around the tapered section for the split retainers. The advantage of using std top collars is that the normal valve cramp will work whereas the smaller dia of the specific beehive top collar needs a different valve cramp. You will still need to have new bottom collars made.
David
- Brian_Walker
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Re: Valve springs catching
Thanks David, just looking at things and it appears that because the stellite weld on the top of the exhaust valve is 3mm higher than the inlet and its the one that was binding it might be caused by shortening the pushrod and now the angle of the rocker is more acute and plate that the tappet adjuster screws into on the end of the exhaust rocker is interfering with the valve collar.
Will still look into the ovate springs. I have order some 7/16" alloy tube to make new pushrods as well.
Brian
Will still look into the ovate springs. I have order some 7/16" alloy tube to make new pushrods as well.
Brian
1951-52 VCH under restoration
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