To all:
Subject: Compression calculation error.
In haste I erred on the little formula to figure your mechnical
compression ratio .
It should read as follows
HG+CC+UV+SV
-------------------------- = compression ratio
SV
I must be typing too fast due to the large amount of mail you guys
are throwing at me lately.
I will have to cut back now and just try to comment on important
stuff and not get into debates.
Dick T.
-----------------------------------
Ramon: I use only iron piston rings because I don't want to have to
bore that engine block any larger in
the future. Pistons bigger than .060 OS simply can't be found and my
custom Venolia forging die which
gives me a tad more than 12:1 is set to machine out a nice .060
piston.
Plain iron rings from Perfect Circle (I believe Ford 1600 engine?)
are the right size and the PC people
always supplied me at no cost as long as their logo was on the car.
The cylinder walls don't wear out but when we freshen up the engine
after say 20 race events, the rings get
changed each time and of course we run with full paper air filters
all the time (inside a cold box) so we
really don't let grit wear out the valve seats and cyl walls, which
would happen fast if we ran w/o filters.
-------------------------------
Scott; you have revealed another of the endless false tales in the
car business.
No the 1592 engine is not "more flexible" than it's big brother
because the large unit simply has more torque
and HP at ALL rpm than the 1592cc. It is certainly possible a
certain 1592 out performed a certain 1725
on some day. Given equal tuning and conditions, the big boy does
more work.
Your 1969 1725 engine would be from a slant installation on the
hardtop slick looking coupe which
replaced the Alpines here as 1968-69 models. It had a single CD
emission carb as std and was a rotten car
and eventually you could not get strut kits or anything else for it
so we junked them out for parts in the 70s.
The WIP carbs are NOT correct on any 1725 engine and are from a
series 1 or 2 model. They are way too
small for a 1725 engine and also run downdraft which hurts flow
efficiency compared to a side draft.
The Stromberg CD 150 is after all, basically 1.50" bore which is
about 37.5mm size.
------------------------
Jarrid; back in about 1964-65 when I was in regular meetings with
Rootes motors in NYC I recall them saying that the new series V crank
was being forged by a new supplier using more modern die equipment
and technique. Yes we all know the prior models with three mains
were also forged steel and would ring when held nicely and struck.
However this 5 main shaft is heavy and complex by comparison and yes..
it too will ring but not like the lighter shaft. As far as my info
is concerned this shaft is steel and always was steel like it's
predicessors.
The enemy (MG, Triumph etc) would have had a field day exposing the
fact the new SV has now got a cheap cast iron shaft ...etc.
BTW, this 5 main shaft has NO weakness or problems. It is bullet
proof to the extreme !
If you still are of the opinion the crank is cast iron, I would say
that a person in the drop forging business or otherwise qualified in
this subject, should examine a SV shaft and advise us all. Until
such time, I say it it a lovely steel forging. I stand ready to eat
humble pie if required by the "expert on forging".
There are some 1725cc blocks which have a drilling problem
restricting #2 main bearing supply drilling but this is easily fixed
when found. Problem being people don't look for the problem. Has this
ever been posted here for all to see???
With cap and bearing removed, look up into the oil way and see if it
is stepped in dia. or is it one constant dia. If neccessary, run a
proper drill up all the way so as to make the hole one dia. right up
into the main supply gallery. Chip removal is a bitch and a perfect
job requires end plugs removed and lots of flushing of the
passageways.
---------------------
Dick T.
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 09:56:09 CDT