-40 with a 617? good luck.

Here is what needs to be in spec to maybe do that:

Compression, must be high, near new.
Valves adjusted
Timing spot on
Starter strong and fresh
Battery strong and new
Check all battery leads and ground, must be making good contact.
Synthetic oil, 5w40 in the sump so the starter can spin the motor over fast enough.
New glow plugs.


If everything is to new spec you have a fighting chance, the PO of my SD did a couple of -20, -30 starts with it when he went skiing but the car was only 13 months old at that point.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200