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Thanx for all those suggestions guys, I'll try some new fuel first. Fuel pump is working ok. Plugs are not wet when turned over. I've never had it running successfully since I've had it! I have only recently changed the carbs to twin 1 1/2 su, previously it had a single 1 3/4. With that it would only run with full throttle, otherwise it would stall, hence I changed the carbs to original spec. Pics available on request - it's an ugly looking beast!! :-/
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This is an interesting one - let me check to see if I have got the symptoms right;
While squirting easy start in, it runs
As soon as you stop the easy start, it stops
That suggests that the ignition is OK
When you turn it over, the plugs don't get wet
When you take the tops of the carbs, you can see the fuel in the jets
This suggests that despite being present, the fuel isn't being drawn out of the carbs
Does the intake system generate vacuum when you turn the engine over? - are there any tappings off the manifold which may be allowing (lots of) air in? Are the engine's inlet valves closing properly?
Are the float heights set corretly - although you can see fuel, it may be that the level is too low, and insufficient fuel is being drawn up through the jet.
Are the jets centred correctly, allowing the pistons to fall fully?
Number_Cruncher
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I agree the problem appears to be lack of fuel.
SUs have a cold start device which iirc pulls something down .. have you one? Are you using it?
madf
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Looks like a carb strip down and clean to get the varnish out.
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Two types of cold-start device were fitted-one lowered the whole jet assy;the other was a choke device(strangler) this was usually on the larger ones.
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Yes you've got symptoms right. There are no apparent problems with the inlet manifold, I fitted this one when I changed the carbs (incidently from an MGB). There is a single hole tapped in the manifold, but it is plugged with a small self tapper and looks to be sound. How can I tell if intake is generating vacuum? I haven't taken the head off, but have removed rocker cover & all valves are rising up & down. Haven't checked float height level, but surely fully choked there would be enough of a gap to let fuel pass. Pistons fall fully with a resounding clonk!
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Just how fundamental a fault do we need to be looking at here? Has the engine ever run, or is this perhaps the first time sine a major rebuild? Is the valve timing correct, or has the chain been put on with the marks say 180 degrees wrong?
When you spin the engine on the starter there should be an appreciable suck at the air inlets, and a gurgle noise of petrol being drawn from the jets. If that is happening, and there is a spark, then an engine will run after a fashion almost regardless of finer points like ignition timing, float chamber blevel, mixture adjustment. You could tip petrol in with a teaspoon and the engine would alternately race and then splutter to a halt.
If none of that is happening then I'd suspect either total lack of fuel or something fundamentally wrong with the mechanical setup.
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Yep I agree with Cliff. My TR7 died on me yesterday and I couldn't figure out what was going on, so called the AA (well the Primera never breaks down....). His checklist was :
Spark
Fuel
Oh, then it should go if we have both. Especially as it really had just been running just over an hour earlier.
If it has "never run (properly)" then I'd be tempted to look at static timing settings & so forth.
cheers,
Stu
BTW. the problem with the TR7 was intermittant, the HT - coil lead was tracking anywhich way it could, which just so happened to be via the over-long fuel pipe. tying fuel pipe up out of way temporarily cured the problem and off we went.
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Sorry, I have just noticed that you've already checked the static timing so ignore my comment.
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As you have never had this running properly, and the fault is obscure, I begin to think the fault is with something very basic and fundamental.
For example, with the old single carb set-up, if it was a fuelling fault, I would still expect the car to tick over (after a fashion!)
I think Cliff's suggestion of checking the valve timing is probably a good one.
Before going to the hassle of stripping the timing case, carry out some basic checks, to see if you are anywhere near - should take about 15 - 20 minutes to carry out the check.
Take all the plugs out.
Using a rod, or screwdriver, probing judiciously into the bore, touching the piston top, turn the crank to obtain top dead centre.
Check to see if the mark on the crank pulley or flywheel lines up properly - (It's not unknown for these marks to be misleading!!)
There are two possibilities
1) you are on top dead centre on the firing stroke, and there will be clearance at both valve for No 1 cylinder
2) you are at the end of the exhaust stroke / start of the intake stroke, and for small movements of the crank, the valves will "rock" - i.e., one will close as the other opens.
Either is fine, but the rest of the checking assumes you begin from case 1.
As you turn the engine in the direction of rotation, you should see, beginning from tdc, firing (case 1 above),
As the piston reaches the bottom of the stroke (as the crank reaches 180 degrees after tdc), the exhaust should open.
The exhaust should remain open until shortly after TDC (i.e. 360 degrees after TDC firing).
As the exhaust shuts, the inlet begins to open, slightly before TDC.
The inlet should shut slightly after BDC, (i.e., 540 degrees after TDC firing)
For the final half turn of the crank, both valves should remain closed, and there should be some clearance.
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If you find all this is happening a bit sooner, or a bit later than as described, or if you find that "rocking" occurs a long way from TDC, you need to look closer at the valve timing.
Number_Cruncher
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If engine has been standing for 6 months has it lost compression due to oil draining from the bores? A squirt of oil in each plughole will solve this.
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Well thanks again chaps, looks like I could have a busy weekend.!! I did think I'd followed the timing procedure correctly, but thanks to your detailed info, I'll check it again. Oil in pots also sounds like good logic, I'll keep you posted.
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If you're checking the timing,go back to first principles-I knew someone who had serious problems timing a TR lump-the pulley was an assembly not one piece and a previous owner must have had it apart and the timing marks were out.He had to set the engine to TDC(plughole) and then re-assemble the pulley correctly.
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I had the same problem with a MK1 2.4 Jag. I could never seem to get the timing marks on the flywheel to make any sense. Some time later, I had the engine out, and discovered the flywheel had been fitted 180° out.
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