First start after rebuild

Carlos

Member
Hello people, I've started the engine for the first time after a rebuilt ( head with new valves and block with new pistons, rings and bearings ).
As a reminder is a 2000TC 9:1 compression.
The thing is that sounds quite smooth, no strange noises.
The oil pressure light goes off, the pressure gauge climbs a little bit ( 30 psi ) but quickly drops to zero.
I quickly switched off the engine, wait for some minutes, started the engine and the same: climbs and drops to zero.
Any idea ?

Another question:
in order to fine tune the ignition ( with a strobe) and carburation; what goes first ?
Tune ignition and then carbs or the opposite ?

Thanks
 
Tune the ignition first then the carbs.

As for the oil pressure guage, the chances are that it's the sender faulty. If you have the Rover oil light switch, that puts the light on when the pressure drops to about 27-28 psi so your pressure would be higher than that. The only way to be sure though is to put a master gauge on it and see what readings you get on that.
 
Hmm, are you using the fitted oil pressure gauge to look at pressure? I would confirm with a mechanical one if I were you. It could be the sender is faulty, hence the odd pressure drop.

does the oil pressure light go back on when the gauge says the pressure drops? If it does I’d say there is an oil problem. If it stays off I’d be inclined to think it’s more of a sender/gauge issue. But either way, best to confirm before running.

Order of adjustments to tune the engine are as follows:

1) Valve clearances (if not already sorted)
2) If on points ignition, points gap.
3) Spark plug gaps (0.025" for conventional ignition, 0.032” for electrictronic with a high output coil as a guide)
4) Ignition timing
5) Carb mixture
6) Carb balance
7) Idle speed
 
Thanks people ! You are great !

does the oil pressure light go back on when the gauge says the pressure drops?
The light stays off after the gauge drops. I will borrow an external gauge and see what it reads.

[QUOTE="sdibbers, post: 389510, member: 615"
1) Valve clearances (if not already sorted)
2) If on points ignition, points gap.
3) Spark plug gaps (0.025" for conventional ignition, 0.032” for electrictronic with a high output coil as a guide)[/QUOTE]
All this already done.
I will go for ignition timing and then the nightmare with the monster HS8.
I've got twin HS4 in my 2500cc TR6 and was really easy, but I guess that with this two beasts things are going to be tough.

Thanks again !!
 
"The light stays off after the gauge drops. I will borrow an external gauge and see what it reads." That's good, sounds like its just a sender/gauge issue (Pretty common on SII cars)


"1) Valve clearances (if not already sorted)
2) If on points ignition, points gap.
3) Spark plug gaps (0.025" for conventional ignition, 0.032” for electrictronic with a high output coil as a guide)[/QUOTE]
All this already done."
"I will go for ignition timing and then the nightmare with the monster HS8.
I've got twin HS4 in my 2500cc TR6 and was really easy, but I guess that with this two beasts things are going to be tough.""

As long as the spindle bushes and spindles on the HS8s are in good condition they're not awful to set.
 
Regarding the valve clearances, have again a look at them after you have run the engine for good.
 
As long as the spindle bushes and spindles on the HS8s are in good condition they're not awful to set.
I´ve made a light rebuild of the carbs ( jets, float needles and gaskets ) but only made a visual check of the spindles.
I hope they are ok.
BTW, in the first start the idle was high (about 1500 rpm). Is that because out of timing ?

Thanks
 
I´ve made a light rebuild of the carbs ( jets, float needles and gaskets ) but only made a visual check of the spindles.
I hope they are ok.
BTW, in the first start the idle was high (about 1500 rpm). Is that because out of timing ?

Thanks
Possibly, it could also be the fast idle of the car was on choke.
 
I´ve checked that. Apparently the carbs are... how can I tell you... at "0" position...I mean with the butterfly closed.
In that case I would suspect either:
1) A massive spindle leak (unlikely)
2) The butterflies weren’t properly seated when the carbs were rebuilt (if you removed them at all?)
3) The clamps holding the bar between the two spindles is tight and one throttle is being held open (try loosening the clamps and see if idle settles down)
 
2) The butterflies weren’t properly seated when the carbs were rebuilt (if you removed them at all?)
I didn't touch the butterflies

1) A massive spindle leak (unlikely)
In that case, should I see petrol around the spindle ?

3) The clamps holding the bar between the two spindles is tight and one throttle is being held open (try loosening the clamps and see if idle settles down)
I will check this.

Thanks sdibbers !
 
You won’t see a petrol leak around the spindles, that part of the carb is under manifold vacuum. You can test for problems there when the car is running. Spray some starter fluid on the area around the spindles. If the engine speed varies at all they are leaking.
 
Sorry! Another doubt:
when I made the static timing, I took the front pulley marks for reference and discovered that didn't match with the flywheel at all.
Is that possible ? Is it ok to use the front pulley ?

Thanks
 
Sorry! Another doubt:
when I made the static timing, I took the front pulley marks for reference and discovered that didn't match with the flywheel at all.
Is that possible ? Is it ok to use the front pulley ?

Thanks
I’d use the flywheel.
 
didn't match with the flywheel at all.

Personally I would check to see where TDC actually is. I made up a piston stop using an old spark plug and a bolt, and rounded the end off so it wouldn't scratch the piston. Remove the spark plug in NO. 1, then check to ensure the piston isn't at the top, and screw the piston stop in.

I removed the other plugs to make it easier turning the engine, then slowly turned the engine over until it stopped, i.e. the piston made contact with the piston stop, be gentle :)

Mark the front pulley where the pointer is, then turn the engine the other way until it stops again. Make another mark on the pulley. TDC is halfway between the two.
 
It's worth re-checking the mixture after balancing the carburettors. When unbalanced, one carb will be sucking harder on its jet than the other, so whatever mixture setting you arrived at before balancing might not be quite correct after balancing.

With the engine rebuilt and the carbs in good condition, HS8s respond well to setting up and a smooth, stable idle is easily achieved. That's what I have found, anyway. I used a Colortune; setting the mixture by ear using the piston lifting pin proved rather inaccurate and hit-and-miss. For balancing the carbs I used a Gunson's Carbalancer and made up an adaptor – a short tube cut from an old exhaust pipe – to fit snugly in the SU intake orifice and give the rubber cone of the Carbalancer something to press on to without any air leakage.
 
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I agree about checking the tappets again after running the engine for a while, tedious job though it is if you discover that the clearances have changed. With mine, after the first 1000 miles all four inlets and one exhaust had closed up by .002in, and another exhaust by .001in. Minimal but annoying, and perhaps caused by the fact that I didn't torque the camshaft carrier down to the full 70lb ft when I was initially measuring the clearances with the head on my spare engine block during the build of the engine. But that doesn't explain why the inlets closed up more than the exhausts. Very strange.

During the build I had set all the tappets to the tighter end of the range, so .008 inlet and .013 exhaust, which I then realised was not a great idea. I have now reset them all at the middle of the range: .009 inlet, .014 exhaust. It was also a chance to re-check and reset the valve timing, which had retarded very slightly as the new chains bedded in. I advanced it by half a vernier tooth, achieved by rotating the inner toothed wheel, which presumably either has an odd number of teeth or the teeth don't exactly align with the axis across the inner sprocket bolts, by 180 degrees plus-or-minus a fraction.
 
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Ok. Thanks for all the info I'm getting.

Regarding the oil pressure, I've borrowed a compression tester ( not exactly an oil pressure gauge ).
After some info sourced from the web, I took the chance and connected where the sender goes, and got a reading of around 48 psi. ( see photo )
I know that is not very accurate but enough to know that the sender is faulty, that there is oil circulating , and that I can run the engine in order to tune the carbs.

Timing the ignition with a light
The car is equipped with emission control system, so the distributor comes with two advance/retard tiny hoses. I disconnected them, plugged the holes ( as instructions ) and set it at 6 BTDC in the pulley. The engine revving at a nice idle of around 800 rpm.
The next day I connected the two tiny hoses to de distributor, started the engine and the idle went to 1.800 rpm ( ! )
Is it normal ?
The carbs

Thanks
 

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