Timing 1.8 k series

[marinabrian]

Originally Posted by mininuts

Makes mine look spot on Brian Was that running ok or not?
Is that engine still in the car? Must have an access panel in the rear wing if it is

Nope, the previous owner took the engine out for some reason or other

However it will give me a chance to look it over properly now it's bolted onto the engine stand

Brian

[minimutly]

Originally Posted by kaiser

No, they would not be quite a way off lining up!
This is plain wrong!
Even 1 mm taken off the head would hardly make any difference.
The bottom mark would not be affected at all, so no reason to use sticks at all, unless you doubt the factory mark.

Fair enough kaiser, you must be right - 1mm, 40 thou or thereabouts, not unknown, add that to an error in marking on the bottom pulley and you can end up asking yourself questions. And anyway, checking piston heights is easier.

Brian, you are the expert here - explain where the safe mark is if it isn't 90 degrees? Been using this for years, never found it to be anywhere else, but allways keen to learn.

[kaiser]

Originally Posted by minimutly

Fair enough kaiser, you must be right - 1mm, 40 thou or thereabouts, not unknown, add that to an error in marking on the bottom pulley and you can end up asking yourself questions. And anyway, checking piston heights is easier.

Brian, you are the expert here - explain where the safe mark is if it isn't 90 degrees? Been using this for years, never found it to be anywhere else, but allways keen to learn.

ninety degrees is half up/down and correct.

[marinabrian]

Originally Posted by minimutly

Fair enough kaiser, you must be right - 1mm, 40 thou or thereabouts, not unknown, add that to an error in marking on the bottom pulley and you can end up asking yourself questions. And anyway, checking piston heights is easier.

Brian, you are the expert here - explain where the safe mark is if it isn't 90 degrees? Been using this for years, never found it to be anywhere else, but always keen to learn.

Take a look at the picture



This engine is in the safe position, and number two and three pistons are further up the bores than one and four, so not exactly 90 BTDC

It is safe to say there is no possibility of valve to piston contact

So the easiest way of checking this is to look directly at the end of the crankshaft, to avoid parallax errors, and aligning the two dimples in the timing gear so they exactly straddle the line cast into the oil pump.

The camshaft gear is easy enough to get right, and the amount machined off the head is irrelevant in the set up, you would have to take off 4mm to make the belt half a tooth out, and realistically that's not going to happen in practice is it

Brian

[kaiser]

Brian. It is 90 degrees.
Why would it be anything else?
90 degrees gives maximum combined protection, all pistons at half way.
No normal engineer would specify anything else!
Believe me.

If you want to check, put a right angle between TDC and safe. Should be 90!

[marinabrian]

Originally Posted by kaiser

Brian. It is 90 degrees.
Why would it be anything else?
90 degrees gives maximum combined protection, all pistons at half way.
No normal engineer would specify anything else!
Believe me.

If you want to check, put a right angle between TDC and safe. Should be 90!

The pistons are not level in the bores with the engine in the safe position Guido, trust me, I've had the lids of these things often enough


Here we have a lower timing cover with the outer crank pulley positioned in the "safe position", so how does that compare visually to 90 degrees, looking at the TDC mark

I know where you are coming from though, but that is the way it is set up

Brian

[minimutly]

Originally Posted by marinabrian

Take a look at the picture



This engine is in the safe position, and number two and three pistons are further up the bores than one and four, so not exactly 90 BTDC

It is safe to say there is no possibility of valve to piston contact

So the easiest way of checking this is to look directly at the end of the crankshaft, to avoid parallax errors, and aligning the two dimples in the timing gear so they exactly straddle the line cast into the oil pump.

The camshaft gear is easy enough to get right, and the amount machined off the head is irrelevant in the set up, you would have to take off 4mm to make the belt half a tooth out, and realistically that's not going to happen in practice is it

Brian

1mm can easy be taken off, assuming you're correct that 4 mm is one tooth, 1mm is .25, add that to .25 on the other cam and you're half a tooth away from lines up - enough to make you wonder? Strange shot that one of the pulley- i'd say 40 odd degrees past tdc Brian, wouldn't you say? I'm sorry, but I'm having difficulty believing it, that said I've never actually checked that carefully on the k,other than to set at level pistons and visually check the cam gear and the dots - never had cause to think there was anything wrong.

[kaiser]

Well, I believe you. It pains me to say, that there is obviously not 90 degrees between the TDC and safe mark, more like 45, it seems.

The TDC must be correct, which means the safe mark is somewhere with pistons down, but not equally, as you have also said.

This is spite of plenty places mentioning halfway, and I have rebuilt this engine a couple of times and never questioned that.

However, you can time an engine anywhere, as long as the pistons and valves don't collide.

I can only assume Rover chose to position the safe mark in such a way that the spring pressure on the cams were the lowest, or that the access to the bolts in the head was as good as possible.

Be this as it may, I concede that the pistons are not at half way.

[minimutly]

Kaiser Brian is winding us up and laughing to himself...
The timing mark is for safe, has nothing to do with the tdc marks, and as I stated earlier if you use it to check timing gives around 40 deg past tdc, not 90 deg BTDC as stated in rovers own manual. I could go out to the workshop to take some pics of all this but I won't, suffice to say I think he's having a laugh.

[kaiser]

Depends on the construction of the crank.
I assume the crank has two lobes at 0 degrees and two at 180.

If so, it means that TDC and halfway must be 90 degrees apart.

Anyway, too late to think about tonight.