Lee;
Sorry to take so long , but a lot of the answers were posted to the
general list in the week or to after my original post. There is just too
much typing at my 9 WPM typing crawl to answer everyone induvidually.
Anyway, the Vizard book you want is his 1989 book on tuning bmc A series
engines for vel stack data and carb porting. Use modified K&N stubby stacks
that you can change into elipsoids.
The anti reversion is almost misleading . By intensionaly mismatching
the
port/header joint,you wind up with a antireversion port. You want the
mismatch on the top of the port! Don't bother elsewhere. 1/8 inch is about
right. Dont match your ports to the header unless the header is smaller(is
that even possiable on a TR?) If you enlarge your ex ports,(and you should)
leave nice sharp edges at the header flange to discourage reverse pressure
waves.
By changing springs and where the advance stops,(by brazing the stop
pad)
you can chang the rate of advance and total advance very easily. Most hot
cams want 10 deg BTDC initial, and the ending advance is dependant on many
things, but usally about 26 deg on a TR6 motor with US pump gas. You want
your vac advance, but you want it to be a throttle controlled, not manifold
vac controlled. I'm not sure what various years of TR's had, but early cars
were probably throttle controled. You can drill your carb for a port
otherwise
Sorry for the poor spelling, but I'm dead tired.
.
don boyd
----------
> From: Janssen, Lee K <lee.k.janssen@lmco.com>
> To: 'dbji@whidbey.net'
> Subject: One Last Try
> Date: Monday, August 17, 1998 5:32 AM
>
> From: "DON BOYD, JOAN IKOMA" <dbji@whidbey.net>
> Subject: Re: ZSvs.SU Carbs
>
> Okay one last try...
> I'm currently in the final stages of a rebuild and I would like to
obtain
> as much information as possible before dropping the engine back into the
> car.
>
> > "with modified ellipsoid entry stacks.(see vizard). fully ported carbs.
> again see vizard."
> I have seen a brief description of Vizards study on entry stack in the
book
> "Building Horsepower Vol. II". More importantly, however, is the source
of
> your stacks. I have seen reasonably prices versions in Moss for about $45
> each are these the ones?
> I haven't, however, seen Vizards text on "fully ported carbs". Could you
> give me the reference so I could do more reading?
>
> > "use anti reversion in the port. isn't worth any hp but it will pull on
> the cam 500 rpm sooner."
> I have heard of anti reversion with regards to headers to prevent back
> pressure from building on the downstream side of the exhaust valves but
> "anti reversion in the port" is new to me. This sounds like a bolt on
item,
> where did you get it?
>
> > "recurved dist."
> I find this interesting since very few people that I've talked to are
> willing to make ANY changes to the distributor. I have purchased an early
> unit with vacuum advance and plan to replace the stiffer of the two
spings
> with a softer one to maximize the advance at 2500 - 2700 rpm rather than
the
> stock value of 5000 rpm.
>
> Thanks for the information
> later
> lee
>
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