Either later today or tomorrow I’ll be doing three first start on my rebuilt engine. New short block with new everything. I pulled off the carbs in one piece and haven’t altered anything so I’m guessing the mix will be at least close.
The Pertronix can’t be set statically so I’ll have to guess and dial it in immediately with the vacuum advance disconnected.
It will be turned over with the plugs out till oil pressure comes up. I don’t have fittings to pump it up, but I assembled it with oil all over the cams and chains.
Then start, set timing, and allow it to come up to temp, and dial in the carbs. How long can it safely idle with a new, tight engine?
I was instructed to retorque after the first heat cycle. I assume this means shut down and retorque the next day when it’s dead cold again?
You might be able to get a read on your ignition timing when you crank it over. Connect a spark plug to your no 6 lead and make sure it’s grounded and hook your light up to that, or alternatively follow the instructions here:https://mgaguru.com/mgtech/ignition/ig205.htm
I like to let the engine run for 15 - 20 minutes at 1200 -1500 rpm when first starting. I’d put a fan in front of the radiator. This is done with the choke idle screws - not the big idle speed screw on the side. Listen to see if the engine starts to slow down during that time. It could be an indication of piston / ring seizure. It’s also essential to bed in new cams or lifters but I assume you didn’t do the head.
Don’t waste your money on expensive oil here - and don’t use synthetic for the first few thousand miles. Don’t put oil into the cylinder bores, or at least any more than you used to assemble the engine - you want the rings to bed in.
Cylinder head is typically re torqued at 100 miles.
You guys ever watch the V8 youtube guys break in a new cam? Running a fresh engine at what? 2-2500? Lots of oil up the pushrods at that rpm. Not an issue with an XK.
What kind of rings Erica? Chrome/ iron/or?
Once it’s running keep a sharp lookout for water and oil leaks especially in those hard to see places like under the intake manifold and around the front of the engine.
I remember visiting the Porsche factory in the late 70’s where a man built the engine entirely and when finished wheeled it to the test cell. After hooking everything up the engine was fired up and taken straight to maximum revs and held there for a minute or two (can’t recall now whether it might even have been longer). When our guide was questioned by the few owners gathered around about this, he informed us that it was standard practice as they did not expect failure of their engines. If the engine failed in any aspect then the engine builder was called back to retrieve, investigate and repair that engine, representing it back to the test cell for a retest. Our guide was then asked if they did this with every engine, when he affirmed this was done to all engines, the look of horror on owners faces was quite something to see, lucky someone had some smelling salts!!
Having noted Terry’s comment above, we had our own Porsche workshops and I would also suggest that the use of today’s synthetic oils in our Jaguars should be approached with caution. Our experience with the older Porsche 911 engines and those of other manufacturers of the period is that these oils being very “searching” produced leaks that the standard 20-50 oils of the day did not. Todays engines are made with better materials, machining and seal technology and these combine to enable synthetic oils to be run. The older engines have a different technology background and were developed to run with the oils of the day.
Our workshop had direct experience of the main dealers using Mobil 1 (the predominant oil of the day) and the owners of these older cars finding leaks develop, which once we changed the oil back to a non synthetic the leaks stopped. Owners were often sceptical until we had their car back on the lifts later to check for leaks and finding that most had now ceased.
I don’t have my handbook to hand but perhaps someone can follow on with what oils Jaguar recommended at the time.
It reminds me of some of the first times I had rebuilt an engine, all the popping and banging while I messed around with plug leads and timing to get the things to run.
So I tried to do better after that and made a point of setting everything up properly beforehand. There’s a great satisfaction gained when a newly built engine fires right up and runs smoothly.
I was always told to retorque hot after the first running of 20 min or so at advanced speed to seat the rings as a general procedure. Then re torque after some miles, a thousand sounds like a good number. YMMV
I always tried to have a witness present to watch the oil pressure gauge and give me the thumbs up as I would be under the hood fiddling with carbs looking for any scary leaks like oil or gas.
Fill with water, not coolant. It always leaks. Everywhere.
Run up to temperature at 1500 to 2000. Don’t let it labour. Let it go until your fans come on then as long after that as you’re happy.
As long as you have put appropriate start up lube on bearings/cams etc “running in oil” is a waste of everything. I just use Valvoline 20W 50 and change at 50 to 100 miles with a new filter.
By all means re-torque after it’s cold. But also do it after a few hours/100 miles.
Don’t baby it too much. Keeping under say 3500 for a few hundred miles maybe. Don’t sit on the same revs for too long. Mix it up. Then drive it hard. I was pulling 5500 on most of my engines by 1000 miles.
There is BTW no science or real knowledge in this. It’s just what I’ve been told. I reckon that as long as you machine it and assemble it correctly it makes NO difference what you do as long as it has oil in it and doesn’t overheat.
Fired it up today, hit on the second try, no leaks I’ve found yet, except a couple drips on the fuel rail. Normal for new fiber washers. Sorry no video. I had my hands full trying to get it timed quickly and get the carbs close to right. It ran a bit hotter than I was hoping considering the moderate weather, it idled for for about fifteen minutes at 90 with occasional blips up to 2500-3000. The fan didn’t come on until I shut it down though so not crazy hot. Bonnet goes on next time, tweak the clutch and I’ll give it a run.
Same here: with all but brand new cam/tappets, it’s really the first 2 minutes where a slow break-in is critical, because of the rough ring/rough cylinder wall interface.
You mean that squeak you heard ages back? That was the belt. I had to add a washer behind the generator bracket to bring the pulley into alignment. There were no funny noises, just quiet purring, almost too quiet.
I agree. I even enjoyed that first drive more because I could also watch the suspension work.
At first I thought I was taking a big chance driving w/o the protection of the bonnet then I realized that if I did hit something not having the bonnet on would actually save me money.
