Engine misfiring on start up

Have fitted a rebored 2200 block to my 71, 2000TC. To this, I have fitted the original 2000TC head and refurbished HIF6 carburettors. On first start up I had to churn the engine on the starter as it missed and backfired until it eventually picked up, and I was able to release the starter.
The engine sounds very rough as though there is a plug missing, lots of vibration, a backfire say every twenty seconds or so, and runs on for a few seconds when I switch off.
The carbs definitely need tuning, but would this cause the engine to run so erratically.?
I have started the car from cold a couple of times with exactly the same problems. The car starts at first attempt when warm, but continues to run roughly.
I fitted new large inlet manifold "0" rings but it is definitely pulling air.
I obviously need to rectify the manifold airleak, but do I also have problems elsewhere?I


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You need to systematically check through and replace as necessary all the normal service items, points, plugs, leads, ignition timing, carb balance and mixture, it may also be worth checking valve clearances and compressions, once all those are correct you can look into air leaks.
I have electronic distributor fitted, I fitted a new distributor cap and rotor arm this morning .With assistance from YouTube I checked the plugs and leads using a multimeter, but new ones should arrive by wednesday
Ignition timing is to spec., and the compression, on all four cylinders are over 200psi
I have done nothing to the carbs balance and mixture,
yes make sure you have timed the cam to the correct marking and it is on the correct stroke...not 180 degrees out and check the cam against the distributor to ensure the two are in sequence. But do all Harvey's stuff first
The diy plug lead kit arrived early this afternoon so have made those up and fitted them.Tried to start the car,but it wouldn't have it.Churned on the starter, but no good.
Disconnected the petrol feed from pump to carb to check the flow, nothing.Tried the joggler on the pump and sucking the pipe(hate that) at the carb end, again nothing
I have now disconnected one of the tank feeds into the reserve valve, am not really sure why, but there does appear to be some intermittent restriction between petrol tank and pump.
Am not confident that this is causing my starting and running problems, but just another problem along the way.
Had an early start this morning. Was keen to check the camshaft and distributor positioning, it made sense and I was somewhat embarrassed as to what I would find.
But no, the camshaft is spot on, and the distributor rotor is pointing to number one cylinder wit h valves closed at 6 degrees BTDC on the front pulley.
The valve clearances are perhaps a little on the tight side. I usually aim for .009 on the inlet and 014 on the exhaust. The feeler gauge was tight at those distances. I will have another compression test as well, while I have a think
No doubt it will be something silly.
I used a different compression tester this morning, a Hawk Command, which I picked up at a car boot sale a few months ago. All cylinders tested at around 200 psi.maximum but the gauge pressure kept falling back to zero on 3 of the tests ( all plugs out, foot on the accelerator) A faulty gauge perhaps?
Should I consider a leakdown test, or am I heading in the wrong direction?

Does anyone have a recommendation for a suitable sealer for the HIF 6 inlet manifold?
200psi is pretty good for a brand new engine; nothing will be bedded in yet so leakdown will be crap anyway. The manifolds are flexibly mounted with sealing by o rings. Finding a leak without the engine running is rather hard unless you strip down the manifold and inspect everything. I've found that TCs will run/idle ok on one carb under certain conditions, even with one of the bells off. I wouldn't use a sealer around the carbs other than factory recommended product (Hylomar) as it can get sucked into and through the engine.


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Ok, will top up the fluid to the neck of the radiator and leave it for a couple of days.Ideally I need to get it running to put the fluid under pressure.
As you say, you really need to have it running to set the level correctly, you need to make sure that it isn't totally full, it needs an air gap in there. I just wanted to know if you were losing any coolant.
Have had complaints of a strong smell of petrol inside the garage from my goodlady.It didn't register with me,as I thought it always smells of petrol. Now I know why.
With three or four petrol cans at the ready I disconnected both feeds to the reserve valve under the bonnet, nothing showing. Fearing, some restriction in the tank, I attempted to pump out the contents, absolutely nothing, dry as a bone.
So, that's it, problem solved, jumped into the everyday motor and bought a couple of gallon of the super 95 petrol. Have reconnected the feeds to the petrol reserve valve and found that the small black plastic feed pipe to the petrol pump was damaged and leaking, which no doubt was the reason for the empty petrol tank. This was replaced.
The new spark plugs had arrived, I fitted those, and ensured the carbs had petrol.
When I turned the starter key I was very confident of a more or less instant start.
I Churned and churned and churned, absolutely nothing.
I was convinced the car would start. The cylinders go up and down in the right order,
I have a good spark which occurs I believe at the right time. I have petrol pumped to the carburettors. The engine must start, it doesn't have any choice in the matter.
Tomorrow is another day.