Finally got to spend some quality time with my 1275 rebuild.
Almost everything bolted on and gaskets sealed nicely.
OK time to check the valve timing and see if what angled keyway I would be
using. The plan was to use the stock "reground" ebay cam advanced to 9
degrees BTDC as per David Vizard.
Before I put the head on, I using a dial gauge I determined TDC and using
masking tape put a marks at the back of the engine. (This was within a hair
or two of the marks on the timing chain gears)
Put on the head and rockers.
Set the valve clearance to .029 on number one cylinder valves; put the
camshaft timing wheel on the front, dial gauge set on the top washer of the
intake (and later exhaust) valves, put the engine at TDC and set a marker for
the timing wheel.
So far OK guys?
This is what I found (and I did repeat the all of the above steps a few times)
Intake opens at 2 degrees BTDC closes at 37 degrees ABDC
Exhaust opens at 46 degrees BBDC closes at 7 degrees ATDC
By my calculations this gives me durations of 219 degrees (intake) and 233
degrees (exhaust)
A far cry from the 230 and 252 of a stock cam.
Am I doing something wrong? Is my math bad? I am surprised that the cam could
that far out of whack. But if my readings are correct, I think as much as I
hate to start taking the engine apart. I don't think this cam will let the
engine breath much.
As long as I seem to going backwards: I had purchased a "head gasket set" and
was surprised that the head gasket wasn't copper. I had never seen one that
wasn't, although this is my first spridget engine. I put it in thinking if I
have problem I can pull the head with the engine in the car easily enough.
What is the common experience with these non copper head gaskets?
I have the original cam out of the engine. Can I get this checked somewhere
out of the engine?
Is it possible to get either of these cams reground?
The original plan was to use a stock cam and Judson, but I have scrapped the
idea of the Judson. So now maybe I should be getting a 266 or 276 cam. I
have already rebuilt the head with new valve springs, and I am not too keen I
replacing these.
Is it possible to put in a "hot" cam without changing the springs. My limited
browsing shows that these cams are sold as sets with the springs.
Why do the manuals call for changing the valve clearances to check the
timing? The normal clearance of .012 is set with the engine cold. On closer
examination of my reference library, I note that Vizard suggets a checking
clearance of .019, while Bentley calls for the .029 (.021 for other than a
1275) There must be a misprint somewhere, which might be causing my
problems.
I havn't had the chance to check the engine using .019 clearances.
Let me know what you think during the commercials on FlounderVision
David Oliner
60 Bugeye
67 TR 4A
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