I'm about to fire up my 1940 SS engine. Any advice?

I’m ready to hit the start button on my 1940 2 1/2ltr SS saloon.
Fully reconditioned. New pistons, bearings etc.
I have cranked it over without plugs and am registering oil pressure and have spark available. Carbs coarsely adjusted as is the distributor.
Once it fires and starts for the first time what revs would you suggest I run it up to and for how long before re-torquing the head?
Any other advice?
You could say I’m a bit gun shy after performing the same on my Mark V sometime back and having all pistons seize in the bore after 5 minutes of run time.
Cheers, Graham

Does it have new/reground cams and followers?

Then run it up to about 1500 rpm for a minute: shut down, check for leaks, repeat, but run at 1500 rpm for 2-3 minutes. Repeat again, after sitting for 10 minutes, then to same, up to temperature.

Hi Paul.
New cam bearings only. Mark V profile cam. Original followers.
Thanks for the sound advice.
Regards, Graham

Fire extinguisher close by?

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Thanks for the reminder

Jordy’s IPhone

Bloody hell. I can understand your PTSD. Surely that was a machining problem?

Not according to the piston supplier who’s clearance specification of .002" were followed by the rebuilders.
Apparently it was my start up procedure (not that they never actually asked me what that was) that was to blame or at least that is what their brother in law “metallurgist” they employed to prove it decided.

Well…& if you just started it up, it was NOT from just being fired up.

But… water under the bridge.

Who was the piston manufacturer?

I have a similar situation coming up, I wish to avoid them!

JP Pistons.
Apparently most engine reconditioners are aware of giving these more clearance than is instructed by JP.

Dad had one XK 120 engine seize up: the manufacturer specced 0.015" to 0.002": all he did was increase that to 0.0025" and it ran fine.

The head should be re tensioned once warm. Turn each turn back a flat and re tension.
Cranky’s here use JP pistons but not the rings they supply.

JP are just around the corner from my place.

OK. I have spoken to a mate who is 82 and a mechanic all his life. He has built (and raced) a lot of engines. He assembled the last Mk5 short motor we dealt with.

He says:

Crank until you have good oil pressure.

Use good quality fuel. Put a LOT of upper cylinder lubricant of your choice (more than the normal, he said a ratio of about 500ml to a tank) in the fuel. This will make it smoke like buggery (his words).

Once it has started, run it at 1500 to 1800 RPM for 15 to 20 minutes; not at idle. Keep a close eye on water temperature and oil pressure and stop it immediately if you’re not happy.

Don’t retorque the head straight away. The gasket needs a few hot/cold cycles to shrink down properly. When you retorque, back each nut off first, then bring it back up to correct torque.

Good luck!


Hi Andrew
Good advice. Hadn’t thought of adding upper cylinder lubricant which I will now do.
I will follow his procedure


Jordy’s IPhone

My machinist said the exact same thing. We are in Adelaide where JP are based so he has had some experience with them.

My advice on retorquing was fro the gasket maker his self… It may depeed of the type of gasket.

Ed I’m not putting myself up as any sort of expert so don’t think my advice is any better than yours.

Graham when you start her up shoot some video for all of us so we can see. Are you in Oz or NZ? My eyes don’t quite work well enough to see the flag.

I’m flying the Australian flag here until Saturday’s Bledisloe cup where upon the Kiwi’s will rise to crush their opponents.
If there is any doubt to my heritage let it be known I can pronounce the following New Zealand place name.

Hey that’s just up the road from Whycookamoocow!

Maybe @Lane_Adrian has s stop there?