1973 MGB (No O/D)
Start car, minor mechanical noises, warm car up (drive 1-2 miles) and loud
knocking starts, no rumble or slap, noise is now there in idle, does not
increase with load. Timing set, valve lash set, carbs set. Is it the Rod Big
end
bearings?? How can I prove this??
I would guess head gasket but check compression hot to confirm. Oil pressure
should drop if it is rod brgs
If so...
Q1. Can the sump be dropped without removing any other parts ??
Yes, by unbolting front mounts and raising engine until trannie meets tunnel. I
put a 2x4 as spacer in mounts to hold it up after jacking from below.
if so...
Q2. Can the Rod Big End Bearings be replaced this way (by me, in the
driveway???)
Unadvisable. If there are significant miles on brgs, and especially if that is
the problem, crank must be removed and checked also.
Q3. READ MY WRITS(!!) Engine OFF, Ignition OFF, pull car into sun in driveway
Tach reads 0 r.p.m.... sun warms up car, tach starts to read... After a while
(with a COLD Unstarted Engine) Tach reads over 3000 r.p.m. HELP!!
Tach is an ammeter, that is it reads current through it. Circuit is from
ignition switch (white wire gets power only with key on) - through tach -
through points - through coil primary winding - and thence to ground. To read
with the key off the ammeter must be getting power from somewhere between
keyswitch and ammeter. This white wire is in the same harness as the white wire
for the ignition lite which is famous for melting down when the alternator
fails because they are in the same harness. In my case they fused together
after the ammeter supplying power to the points and coil with the key off. Hard
to shut off. My guess is a high resistance short in the keyswitch or the wires
coming from it.
Just my guesses
Luck
Ernest
barrister@lawref.com
|