OT: Any Jag or car-engine-sages here?

[Catfish]

A bit OT here:

Not my car, but we have a problem: engine rebuilt, crankshaft in, oil pump and distributor shaft in, also primary chain at the front and the chain cover in place, no cylinder head, no camshafts yet.
All is well oiled and fitted with torque wrench -

Now when we turn the crankshaft, we need around 30 Newtonmeter to turn it (seems a bit much, but it's a 4,2 liter six cyl., pistons going up and down, primary chain with spanner mounted), however every 2nd revolution we have a "hard point", at which you need 40 Nm to overcome a sudden resistance.
A short resistance every 2nd turn - so my idea was it has something to do with an attached component that does 1/2 turn for every full crank revolution, right ? But the valve train is not fitted - no cylinder head.

My guess is it cannot be the crankshaft and main bearings itself, because it would then either happen once in a turn, or being a bit stiff during the whole revolution.

I also think that it should turn much easier than needing 30 Nm for turning, but i am not an expert with the 4.2 block.

Hmm Anyone ?

Thanks and greetings,
Catfish

[BrucePartington]

Model and year of vehicle, please, so I can look for engine layout.

Flying blind, I'd assume the said distributor shaft is the ignition distributor. If it is already in because it's driven directly by the crankshaft, that would be a "person of interest", since ignition distributors turn 1/2 per crankshaft complete turn - on a conventional four stroke reciprocating piston engine, that is.

[Wolferz]

Originally Posted by BrucePartington

Model and year of vehicle, please, so I can look for engine layout.

Flying blind, I'd assume the said distributor shaft is the ignition distributor. If it is already in because it's driven directly by the crankshaft, that would be a "person of interest", since ignition distributors turn 1/2 per crankshaft complete turn - on a conventional four stroke reciprocating piston engine, that is.

It may be different on a Jag six banger but, I think distributors are usually turned by a gear machined into the back end of the camshaft.
It could be the oil pump building up pressure as you turn the crank. If the crankcase is full of oil that is.

Can two blind mechanics land a repair safely, Bruce?

Edit: I reread the OP and I gather it's a DOHV setup? If that's the case, then the distributor is being driven by a gear on the crank. As is the oil pump. The most likely case of sudden resistance would be the oil pump building up pressure. Since most oil pumps are driven by a lay shaft attached to the distributor...
Try removing the distributor and the oil pump drive shaft and then see how things spin.

[Catfish]

It is an early 2+2 4.2 litre 'E' from 1966. Engine also built in 1966, presumably original. DOHC engine with primary chain, and a second one driving the two camshafts.

Oil pump and distributor are being turned at the fore end of the crankshaft, the take-in nozzle
of the pump is in the rear, via this metal tube going from the pump to the rear part of the sump.

There is not enough oil in the oil pump to build up real pressure, it is just well oiled.

I agree it must be pump or distributor shaft, since the valves and camshafts and the whole cylinder head is not yet mounted.

[Buddahaid]

Did the crankshaft spin easy after the main bearings were fitted and after the connecting rods were fitted?

[Catfish]

That's the problem. He didn't check.

[Buddahaid]

No choice but to start disassembling until it frees up. In any case it would be best to have the crank, rods and pistons balanced by a machine shop before continuing. The motor will run smoother and last longer.

[Catfish]

Yep. Well we know every of the 27 oil sump screws personally and by name, so ...

Certainly means new gasket. It is cheap, but you have to order it and it takes time ...

[BrucePartington]

Please keep us posted. Classic car repair and restoration is my number one passion. In fact my speciality.
If I where any closer I'd be glad to stop by and join in on the fun. I'd love to sync those SU's and tune it to purr like a kitten. I've recently done that for an MG-A fitted with an MG-B engine (1.8 L), a Triumph GT6 MkI (Stromberg carbs) and an NSU RO80 (Wankel engine w/Solex twin barrel carburetor).

Have a service manual available in Braille as well, for me and Wolferz.

[Wolferz]

Originally Posted by BrucePartington

Please keep us posted. Classic car repair and restoration is my number one passion. In fact my speciality.
If I where any closer I'd be glad to stop by and join in on the fun. I'd love to sync those SU's and tune it to purr like a kitten. I've recently done that for an MG-A fitted with an MG-B engine (1.8 L), a Triumph GT6 MkI (Stromberg carbs) and an NSU RO80 (Wankel engine w/Solex twin barrel carburetor).

Have a service manual available in Braille as well, for me and Wolferz.

Since I can twist wrenches by feel I'm sure a manual in braille wouldn't be too hard to figure out.

Now, since the report of no oil in the sump area for the pump to pick up and squirt all over everything, it's gotta be a slightly too tight or too dry rod bearing starting to seize on either the up or down stroke.
Definitely don't want to fire that puppy up and have it spin out the bearing. It would pay to check them all again with some bearing floss to insure they're within tolerance.

Bruce, have you ever had the pleasure of tuning the triple carbs on a '53 Corvette inline six?

[BrucePartington]

Originally Posted by Wolferz

Now, since the report of no oil in the sump area for the pump to pick up and squirt all over everything, it's gotta be a slightly too tight or too dry rod bearing.

Remember: it binds every other turn of the crankshaft. To me this equals to binding of the distributor shaft/gear.
When I started to read the OP I thought: "they must have lubed the back of the bearings." But then I read it happens every two turns of the crankshaft - which exonerates the crankshaft and pistons. When I read the distributor shaft is already in, as well as the oil pump, I had very little doubt about who to "bring down town to have a talk". We'll have to wait for an update from Catfish.

[Wolferz]

Originally Posted by BrucePartington

Remember: it binds every other turn of the crankshaft. To me this equals to binding of the distributor shaft/gear.
When I started to read the OP I thought: "they must have lubed the back of the bearings." But then I read it happens every two turns of the crankshaft - which exonerates the crankshaft and pistons. When I read the distributor shaft is already in, as well as the oil pump, I had very little doubt about who to "bring down town to have a talk". We'll have to wait for an update from Catfish.

You're right. We need an update. Sans proximity to the motor stand, it's as difficult to diagnose as a problem relayed via telephony.
From the mechanical point of view there will be some resistance expected from the new (unseated) piston rings. With the reported resistance every second turn I suspect a little binding on a piston stroke on either the power stroke or the exhaust stroke. It could also be a bent distributor shaft or a bad tooth on the gears.
I've had my mechanics question my diagnostic skills. Usually to their detriment.
OK, so you pulled the left front wheel when I told you the problem is in the right front? You're old enough not to be daft! I told him.
I learned the hard way when my father assisted me with a new radio install on my first car. The radio worked fine...when the turn signals had power applied. After that debacle, I did everything myself when pop wasn't around.

[Catfish]

Hi again,
we already found out about the problem some weeks ago, but since some were interested, here is the problem:




He aligned the teeth carefully, the "Tragbild" (no english word i know, sorry - meant is where the surface-point of the teeth touch the "worm drive") is so that performance will not suffer, and no additional wear will occur.

Anyway, the turning-around is now a smooth and even 30 nm, during several revolutions, measured with torque wrench.

I think the worst is not bringing the '66 300 kg Coventry grey cast block back to life, but this rear axle. God, what a construction.

Thanks and greetings,
Catfish

[Wolferz]

It's kind of hard to tell from that slightly blurry photo but, are a few of those gear teeth missing that tragbild you speak of? Serrations in English I believe. Yes, I can see where that might cause some binding.

[Buddahaid]

Looks to me like it was running up against a too long bolt. On a similar note, I would seriously consider a Pertronix Igniter system to replace the points and condenser. I use one on my Triumph and did so with both VWs I had. No more ignition problems due to a shaft wobble and the timing doesn't change when points wear down. Ignition tune up are just plugs, cap, and rotor exchanges. It also doesn't require any modification to the distributer. Just exchanging parts.