Stroked LQ9 (427) 10:5 hard to crank over - killing Red Top Optima

[autofil]

Hi! Just installed a stroked 427 based on the 6,0 litre LQ9 in i 01 Tahoe. New engine and ecm from Turnkey Engine Supply. The engine runs great, but is really hard to turn over/crank during starting. Stock cranking advance.... New starter, Stock Earth and positive supply, New red top optima. Should I try to reduce the cranking advance...and just how much...? Please see Attached hpt file. Ny orginal tune 13.11.2013 med ny motor, rev 05.hpt

[jimmyblue]

Well, it's both higher effort and tight rings, so cranking
ought to be more difficult. You might want to scrub all
of the starter current loop connections and retighten,
before you chase other things.

Also my hot lead had been badly chewed by two leaky
Delco batteries in a row, and the electrical connection
to the hot cable conductor was really poor. I was able
to solder it on mine, with some effort and a big-ass iron.
You ought to look at the voltage across the starter posts
while cranking, and across the battery posts - this may
narrow it down for you.

Not that reducing the cranking advance is a bad idea,
if all you get is "Unh". But I've been around other 427s
that did not seem to have a problem cranking.

[autofil]

Thank you JimmyBlue :-) I will test out the leads for the battery and so furth. But I will test the benefit of reducing the advance since that is an easy og if that helps.... 4-5 degrees reduction should not do any harm as a try. Thanks again :-)

[autofil]

I did just now reduced the advance timing With 4 degrees. Cranked better, but now it was Cold. Need to test further when hot. Will check all terminations for Earth and hot Connection.

[wesam]

Try adding 10% fuel while cranking

[autofil]

wesam; I will also test that out, thanks! :-)