Bob,
So far, no luck. Cruise at 45 to 50, nail the
throttle and KAPOW through the carb every time every time.
Crane Cams had a little note that too tight of an adjustment
could cause a backfire through the carb if the lifter
pumped up and held the valve open. I have done two
valve adjustments so far. Presently, one turn past
the pushrod contacting the lifter. May go less.
Have ordered a 1" dial indicator to check the cam lift
for damage. plan to fabricate a push rod tool that will
catch the lip of the hydralic lifter so I will be able to
get a valid reading on the hydralic lifter. The tool has
to be able to get past my pushrod guides and through the
holes in the head before expanding to 7/8" at the lifter end.
Have never seen such a tool for sell. Crane Cams says one
must put in a solid lifter to measure the cam. If I have
to pull the intake to put in the solid, I may as well pull the
cam and measure it on the bench!
I assume your adjustment order is for the 260/289 firing
order. The 351C has a different firing order. Crane says to
adjust the intake just as the exhaust is opening and vice/versa.
I was adjusting per the instructions in " How to rebuild your 351C"
At 08:10 AM 1/30/2001 -0800, you wrote:
>Jim, Listers
>
>I hope you are making progress on fixing the backfire gremlin. I thought I
>would take the opportunity to contribute my two cents worth to the List on
>adjusting valves. Since I have a solid lifter flat tappet cam, I do this
>procedure every few thousand miles. For the majority of you Listers with
>hydraulic lifters, the procedure is basically the same, just tighten 1/4
>turn past zero lash. First off, I don't adjust with the engine running.
>Second, I don't adjust with the engine hot. Adjusting hot or cold is the
>same if you have cast iron heads; if you have aluminum heads, that's another
>story because the thermal expansion of iron/steel is different than cast
>aluminum. In the case of aluminum heads, check the lash on one or two valves
>right after you turn off the engine, then wait for it to cool off to a
>comfortable temperature and check it again and correct the adjustments
>accordingly. With the engine at a comfortable temperature you have plenty of
>time and can do a very accurate job on the adjustments. When it's hot and
>especially when it's running, it's a difficult and messy job and very hard
>to be accurate.
>
>When I do my adjusting, I do it every 90 degrees of engine rotation. I know
>this is overkill as you can get away with doing it every 180 degrees. But I
>use a hand-held switch that lets me crank the engine over while watching the
>crank angle and just move it to approximately the 90 degree positions; eight
>positions in total, then I repeat again and double check the lash. With this
>procedure, I can set all the lashes to within better than 0.001". Of course,
>this degree of accuracy isn't necessary with hydraulic lifters. A quarter
>turn past zero lash is sufficient and also prevents lifter pump-up should
>you ever over-rev and have valve float. Here is the adjustment sequence I
>use:
>
>Crank Angle Intake Exhaust
> cyl. # cyl. #
>TDC 8 5
>90 ATDC 1 4
>180 ATDC (BDC) 5 2
>270 ATDC (90 ABDC) 4 6
>360 ATDC (TDC) 2 3
>450 ATDC (90 ATDC) 6 7
>540 ATDC (BDC) 3 8
>630 ATDC (90 ABDC) 7 1
>TDC 8 5
>
>I hope this table comes out legible. Note, of course, that "TDC" refers to
>cylinder #1; i.e., the valves are closed. In practice, you don't have to
>start at #1, just which ever #1 or #6 happens to be at TDC when you rotate
>the crank to the TDC mark.
>
>TTFN,
>
>Bob
>
>
James Barrett Tiger II 351C and others
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