Triumphrat

ohiorider · 08-20-2007, 05:16 PM

Has anyone found a source for metric feeler blades in increments of .01mm (.15mm, .16mm, .17mm, etc?). I found a set on the web that comes with loose blades, but I'd like to find something locally.

I'm starting on the valve adjustment, and I'd like to use more accurate feeler gauges. The best I have in my toolbox are in increments of .001" (001, 002, 003, etc), but that makes for some pretty big jumps from a metric standpoint, especially when trying to get the valves spot on. For example:

.006" = .152mm
.007" = .178mm
.008" = .203mm
.009" = .229mm
.010" = .254mm

Maybe I'm being too particular, and can get close enough with the gauges I already have. It's obvious that all my valves are loose. All intakes are approx .254mm, and exhausts are at a loose .30mm. So going .050 thicker on each the exhausts and a bit more on the intakes should bring them within spec. No wonder she was starting to sound like an old Triumph from back in the day. Better loose than tight, anyway.

Any thoughts?

Bob

bendavanza · 08-20-2007, 06:11 PM

A feeler gauge set I have shows both measurements on the same blades.
-Ben

Geoff · 08-20-2007, 06:26 PM

The metric measurements, as you noted, are much finer. and the valves have really only a pretty small window of correctness. I bought a snap-on metric feeler guage that does nicely, for about 10 bucks
G

Big_Rick · 08-20-2007, 06:26 PM

You can do it with standard feelers no problem. You just have to do more converting.
The inlet valves are .15-.20 mm (.006"-.008") and the exhaust valves are .25-.30 mm (.010"-.012") so just aim for the middle.
There's no need to get any more accurate than that since valve shims only come in .025 mm increments. (.001")
Good luck with 'em.

ohiorider · 08-20-2007, 08:14 PM

Thanks all - the Snap On is something I'll check into, Geoff. I could have the BMW shop's mechanic order it for me off the Snap On truck. I'll probably shoot for the mid-range, between min and max this time (good point about the available shims, Rick)
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I'm still torn as to whether to experiment by changing the cam timing one tooth (one tooth advance for exhaust - one tooth retard for intake) I've run this past several folks on this forum, including SCC Bonneville and Jojje, who have already done this, and reported improved lower-end torque.

That decision will come as the cams are replaced. Aside from the fact that the 790 cams have slightly longer duration, this change would make the valve overlap (the period when intake and exhaust are both slightly open together) almost like the 865 engine's overlap, that is, not as great as the stock 790 timing.

If I do this, I'll provide documentation as well as before and after dyno information. As a matter of fact, I already have a slide set prepared that shows stock and modified cam timing. All that remains is to have the "after" dyno run done, and finalize a dyno graph showing before and after.

One tooth doesn't sound like much, but it equals 15 degrees of crank rotation, per Jojje.

Bob

sweatmachine · 08-20-2007, 08:20 PM

hey Bob, want some more torque for free? Want to trade cams?

I'm only 1/2 kidding...

ohiorider · 08-20-2007, 08:38 PM

Uhhhhhh .... Sweat, think I'll hang on to the 790 cams. It appears I can achieve 865 type cam timing with minor change of one tooth (as previously described).

BTW - has anyone ever been able to pull any info re timing, lift, duration, from the company in New Zealand (or Oz) that makes the aftermarket cams for Bonnies?

Bob

denny · 08-20-2007, 09:48 PM

I found my Metric Feeler Gauges at PEP Boys.
I guess they have stores in Ohio??

HiVel · 08-20-2007, 10:02 PM

I am still lookiing for metric drill bits!

HiVel · 08-20-2007, 10:04 PM

And a set of JIS screwdrivers. These are like Phillips head but are Diffferent -"Japanese Industrial Standard". Any body got a source for these and the metric drill bits?? HELP!