Mike:
I do modifications very carefully, so as not to overdo anything that is
going to cause problems later on, so, when I rebuilt my TR6 head, I only
raised the compression to 9.5:1. This increase did not need shortened
pushrods, or shimmed up rocker pedestals, or anything. Also, from the
competition manual, (if my memory is correct) I rounded off the four sharp
ridges cast into the combustion chambers, as a precaution... probably
overkill for only 9.5:1, but definitely a good idea for 10.25:1. I beleive
that the manual says anything 10.5:1 or over will need shortened pushrods
to correct the geometry... I also matched the intake and exhaust ports with
the intake manifold and header, as recommended in the manual, a good idea.
I had the machine shop install hardened valve seats so that I would be able
to run unleaded fuel, also a good mod, I think. Hope these are useful
tips.
Good luck!
Pete Chadwell
>>Recently bought the Triumph TR-6 Competition Preperation Manual from TRF for
>>my 74 1/2 and am wondering if anybody has made any of the engine performance
>>mods discussed in the manual?
>>Specifically I am interested in
>>- decking the head to increase the compression to 10.25 (any piston mods
>>needed for clearance? How about push rods?)
>>- put a new grind on the cam
>>- mild port on the head, matching the intake and the exhaust to their
>>manifolds
>>- balance the motor (crank w/rods, pistons, wristpins (& flywheel?)
>>Are the charts shown accurate? Is there a cross-reference for the part #'s
>>that they list in the Comp manual to either TRF or Moss part #'s?
>>The car is a daily driver, so it must end up well behaved.
>>
>>How is everybody getting headers, non-stock carb setups, etc. thru smog
>>testing? I'm in northern CA - is it just the CA people who take a beating
>>with the smog issue, or is everybody faced with this? When I smogged the TR
>>early last year, the mechanic really worked me over since he had never seen a
>>TR-6 before. He drug the smog manuals out and when there was a question over
>>the vacuum lines that come off the radiator hose it took a long
>>"conversation" to get him to pass the car. Can't imagine trying to get a
>>non-stock setup thru...
>>
>>In the next few weeks I'm planning on replacing the Michelin red-line tires
>>with a new set of radials. It seems that 205/60/15's are the tire of choice,
>>but I'm concerned that since I don't have the O/D unit I'm going to need to
>>wind the motor out to run it on the freeway. My speedo registers 70mph @ ~4k
>>rpm. Also the speedomoter will now register an incorrect speed with the new
>>tires. Does anybody have an idea of how many mph I'm going to loose as a
>>result of going to a smaller tire? How do I re-calibrate the speedo?
>>
>>On the subject of the O/D unit, the car originally had a unit in it ( has all
>>the electrics in the steering column and I believe the comm #, noted below,
>>shows it as an od car) but the DPO has a non-O/D tranny in it. What
>>specifically do I need to do to add an O/D to my existing non-O/D tranny?
>>
>>My meager contributions to the list - RE:carb dashpot oil, the Bently manual
>>calls for std 30 weight oil, RE: brake servo - I had the same symptoms,
>>changed the servo and brakes were fixed. With the new stopping power, I
>>thought I was going to tear the front end off the car since the braking was
>>so much stronger. Bought the servo from Triumphs Only in San Jose. Worth a
>>Mr. Franklin and a half to make sure that you are safe. RE: Nick and "The
>>Dreaded Clunk", I too have this problem in 3rd and 4th gear, following your
>>thread with interest.
>>
>>Wasn't there an address on the web where one could look up the commision #'s
>>on the TR and get the car info online?
>>
>>Thanks!
>>
>>Mike D'Ambrogia
>>Red 74 1/2 TR-6 CF 27282 UO Aug '74
>>
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