Karl and Sergio: Yes, when you make a change in timing setting there is
usually a slight or big change in idle rpm which in turn changes the air
velocity across the jet bridge on CD type carbs (less affect on downdraft carbs).
You may find a slight touch up of mixture to be needed, as well as some
adjustment to idle speed.
You post was unclear as to what you meant "15-20 deg" reset to 10 deg. I
assume this means you originally found timing set at idle to be 15-20 BTDC
and when reset to 10 deg you had loss of power??
This "may" be an indication of another problem you have.
With a setting as high as 15-20 deg the engine is overadvanced to start
with but certain engines seem to like this sort of setting and give a peppy
accel. with it. However, if that engine then builds up another 26 deg of
cent adv. it is certainly a candidate for detonation damage !
How is it possible for an engine to "like" an over advanced timing setting?
There are two main answers, as follows:
1. The engine has very poor compression from ring and/or valve problems.
It simply cannot detonate (knock) because it makes only low compression psi.
2. The engine has a badly worn timing gear/chain unit which has retarded
valve timing to some degree. This robs power and yet the engine does idle
well and has acceptable power below say 3000 rpm. At higher rpm it is a
sluggard. This wear in the camshaft drive has an affect on the distr.
timing so the tuner finds that more basic advance seems to give better power.
I would suggest doing a cam timing test where the true open/close angles of
the valves are measured on the pulley (which has had a tape installed upon
which you marked a full 360 deg circle of degree lines.
Open/close angles for intake and exhaust are quoted in the shop manual and
I "assume" they are correct when std. valve clearences are set.
On aftermarket cams it is now normal to state valve timing when the valve
is set properly AND when opened to some finite amount of lift, like .050".
Due to cam lobe ramp being long and shallow, it is virtually impossible to
see exactly where a valve "starts" to open or is fully closed. By using the
.050" position we can hit a precise position on the degree wheel.
However......I never bothered to determine Alpine valve timing for stock
cams using the more precise methods and just make certain my chain and
gears are tight and have no wear. This assures proper valve timing.
One final comment......the metalastic crankshaft damper (pulley) has been a
source of endless trouble and has been found to have a loose Woddruff
Keyway slot which allows it to shift positions.
Also, the outer rim of the pullet can loosen on its rubber bonding and
shift around from original positions. Wow! can you imagine some poor guy
trying to get ignition and valves set with this sort of condition.
Check everything out to see if you have problems like these
---------------------
Emmett: Your tale of overheating is going to need more talk than I have
time for. Alpines, when clean and normal DO NOT overheat at idle on any
day below say 95 deg. F.
As all cars age, the radiator core limes up the passageway in the tubes,
engine block accumulates deep layers of sludge, rust, rubber, dirt and
crap. Alloy cyl heads corrode inside and also can build up blockage
materials. Radiator caps LOSE their original pressure holding specs.
Coolant mixture which is too high in antifreeze is a poor heat conductor
compared to water. Thermostats open by the action of a wax pressing a
piston (wax pellet type stat). When this type stat is overcooked just one
time, some wax pushes out and is lost. Thereafter, this cooked stat CANNOT
open fully. When driven normally a stat is not called upon to be wide open
but at idle it may need to do so and now it cannot open 100%....result is overheating.
You may have some or all of these problems present. Do not waste money
doing costly things first...do cheap things first !
Have the stat out and boil it in a pan with a good lab thermometer.
As an example: a 180 deg stat should start to crack open at about 172-175
deg and be fully open (about 1/2") by 178-182 deg. When cool, it should be
100% closed !
Have a professional radiator shop look at your radiator for evidence of
lime. If needed, have is totally dissasembled and rodded out or replace the
core itself if it is too thin or questionable.
Have a engine block core plug (not proper to call them freeze plugs)
removed and see what lies behind. If serious crud is seen, this block and
head needs plugs removed and pressure cleaning and/or rodding out the block
passageways as well.
Find an older experienced radiator expert and take his advice. I cannot do
much here except to alert you and others to these various conditions.
I was a service manager for Rootes when you car was new.
----------------------
Karl; I spotted your message and want to add a comment for you as well.
Any engine must run at designed coolant temp in order to have proper power
and also to obtain max. engine life !! Too cool and you build sludge and
crud which ruins engine life in various ways. Funeral cars have the
shortest engine life span known due to not getting much HOT operation.
In your case you must start with known data not guess work. Measure
coolant temp. in the top tank or as near the stat as possible. If dash
guage agrees, then yank that stat and put in one which works ! If tank temp
is proper, then fix the guage problem. Get that car running at proper heat!
The hotter the coolant, the more power (up to a point of course) and the
better the engine life.
Cars operated in short trip conditions need more frequent oil changes as
well. Highway driving is the least wearing of all.
General Motors published a paper stating they completed several years
research and found that 90% of all engine wear occurs during the first 30
seconds after cold starting !!!!!!
This was further explained in laymans terms to mean : When you drove 1000
miles in one day, non-stop, whatever wear the engine received, 90% happened
within 30 seconds after the cold startup.
This is the MAIN reason why thin multi-grade oils have added greatly to
modern engine life. Thick oils simply allow too much wear before they warm
up and can get into friction areas and bearings to their best ability.
Normal condition engines which have normal bearing clearences do NOT need
thick oils like SAE 40 or higher.
Cars in normal condition are best protected in summer temp by a 10W-30
viscosity oil and in freezing regions, a 5W-20 does the job best !
Engines with loose bearings or other problems "may" benefit from thicker
oils but even these need careful evaluation first.
------------------
I have owned personally, 23 Alpines of various types and owned and operated
a restoratrion shop for British cars and Rolls Royce etc.
Some have asked about my background in this business and I will say that I
have been the Lemon Law technical expert for the Florida attorney general
office and serve as auto consultant for the St. Pete Times newspaper.
I was on the original team writing the Colorado emissions laws and taught
vocational auto mech in CO. I was an automotive publisher for the Times
Mirror Corp and was listed in Whos Who book as an automotive race car
designer and educator etc.
While in CO I owned public repair garages as well as Jaguar and SS Car and
antique car restoration business in Denver area. I started racing back in
1953 with a 4 cyl Healey. I raced my own Alpine- V in SCCA F Production
class and won my share of races over the years .
I recently gave away my remaining Alpine spares to a young friend in AZ and
have been on the e-mail helping him get a V up and running. He advised me
to look at this BB group and i do find it interesting to reply to people
when I think I have an answer of value.
Unfortunately I am more active on the Prodigy shooting sports BB and am
damn busy with my financial advisory business, so you may at times not hear
from me. Also, I found that there is simply too many mails showing up in
my mail box since I joined the list. I will how this all works out later.
Dick T.
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