Classic cars forum & vehicle restoration.

[Bitumen Boy]

Hi guys,

Having some running problems with the Herald and looking for ideas - warning, it's a bit of a saga! Basically
it all started a few weeks ago, when the symptoms of valve seat recession got to the point where a proper unleaded
conversion was unavoidable. Apart from that, however, it was running fine. I took the head off, condition of
valves/seats as expected, scraped some carbon off the piston crowns and exchanged the whole head assembly for a
recon unit from one of the well known Triumph specialists - was going to have it done at a local place I've used
before, but they quoted me silly money for this particular job. So far, so good.

Got the new head on and torqued down, replaced all the other bits and pieces, set the valve clearances according
to the Autobooks manual (anyone had problems here before?) as it was first to hand, time for a test run. Started no
problem, ticking over smoothly and quietly - perhaps too quietly, with hindsight - in the garage, great! Got
changed and headed off towards town, 2 miles down the road. Seemed a little down on power going down the street
but didn't think too much of it, figured things would want tweaking a bit once warmed up properly. Got out onto
the main road, started missing above 40mph, then started making one helluva row and lost most power. Road was
hellish busy, but luckily it's slightly downhill and so managed to limp to the next layby, where removing the rocker
box revealed #1 pushrod had come adrift - whoops, couldn't have been properly entered, put that right as best I
could on a hot engine in a layby! Got the remaining 1/2 mile to Tescos no problem, a further examination revealed
nothing amiss, so after picking up a few bits headed for home. Back out on the main road, however, it started
missing again over 40 and after turning round in the same layby, I figured on taking the old road back up the
valley - but to get to that from the town end involves climbing a steepish hill (about 1:8 or 1:7), which proved
impossible as the same symptoms emerged again. At this point I'd had enough, and phoned for a tow home, where
#1 pushrod was found adrift again. Next day, engine cold again, I examined all the pushrods and rocker gear, found
no problems bar a few scratches around #1, reassembled everything and reset the clearances, this time as per Haynes.

Again, started OK and ticked over so-so this time, but ran like a pig on the road, no power, misfiring, max speed
about 20mph. Back home, start again. This was about a fortnight since. I haven't had every day day at it, with having
to go to work, but tried every damn thing I can think of and still it's dragging on. First, I went through the igniton
- new (or known good from stock) plugs, points, condenser, diz cap and rotor arm, HT leads, coil, LT leads replaced or
bypassed. No gammon. Found an air leak at the manifold though so had that off again, another new gasket, a noticeable
improvement - but not there yet. This was the last thing I did to noticeably improve matters. It starts no problem but
doesn't idle too well and feels, on the road, very much like there's not enough fuel getting through. Runs fine up to
20mph, a wee bit lumpy at 30 (though extra throttle helps momentarily, as if the accelerator pump on the carb is doing
its job) lousy at 40, starts spitting back through the carb and threatens to stop running altogether over 50. When
accelerating up through the gears it seems to run out of revs around 35mph in third, it does, however, pull up hills
tolerably well in the lower gears at road speeds little lower than usual. Fuel side, I've cleaned out the carb
(Solex B30 pse1) umpteen times, and eventually substituted it for another - no difference. Cleaned out, then swapped,
the fuel pump - no difference. Blown through all the fuel lines, including the tank pickup, and replaced a grotty
looking filter - no difference. Checked the breather in the fuel cap - clear. Replaced air cleaner element, even tried
running without it - no difference. A compression test has shown no anomalies, no water in the oil, no oil in the water
and no sign of either entering the cylinders. Engine is 1147cc from Mk 1 Spitfire wearing Herald 1200 manifold, carb and
diz (bit of a mix, but it's been running well for long enough like that), rebored +.030", though whether the old head
was the original for that engine is anyone's guess. Temperature gauge readings totally normal - warms up quickly, no
sign of overheating.

So, unless you guys have any clever ideas, I'm looking at two main possibilities. #1, there's still an air leak around
the manifold, perhaps it's warped or cracked, though how is anyone's guess. #2, the engine timing's out after the first
failure to proceed problem, jumped a tooth maybe, I doubt that's very likely with a steel chain rather than a nasty
rubber band, but I've read of it happening. Timing chain, by the way, is not old and rattly, but was replaced about
5-6k miles ago. Right now it's a case of deciding which one to investigate first!

[Roger-hatchy]

I presume you have re-checked the head bolts / nuts.

Check the plugs again

I changed my headgasket recently, did about five miles, round trip, that evening, got a lift to the club meet when it was obvious the DLM didn't want to play
.
Checked the torque the next day and they all took at least half a turn to re-torque,
Running fine, Sorted? NOT.
next morning, after the monsoon had stopped, I intended to go for a test run, misfiring again.
Found one of the NEW plugs was U/S, the insulator was broken inside the main body.

Re-torqued a few days later just under half, then again a few days later another little bit.
Checked twice since and no movement.

[Roger-hatchy]

Just re-read your post.
How bad is the spitting back through the carbs.
Mine did that when the throttle was blipped, found it was the headgasket blown between three and four.

[47Jag]

If the pushrod is jumping out then I reckon you have a sticking valve.

Art

[Bitumen Boy]

Sorry for no updates on this thread guys, not had time to even look at anything as my dad was carted off to hospital the other day after taking a tumble on some steps. Looked dramatic at the time but he should be OK with rest, they're keeping him in for a few days under obs though so with the animals and everything I haven't much time to spare!

[Jim.Walker]

I find setting valves according to Autobooks AND Haynes puzzling. How CAN the instructions differ? Not something a half competent amateur should even need to refer to anyway except perhaps to determine whether "hot" or "cold"?
I cannot see how incorrect valve clearances would produce your symptoms (though lack of clearance might), but unduly small clearances are easily set on that engine.
By the nature of the valve/spring set up only very light springs are possible and it is almost impossible to set valve clearances anywhere near correct by feeler "drag" in the gap. Certainly a novice should re-check the set the clearances by ensuring that a 1 thou' less feeler selection passes cleanly through the gap with no "drag". In this case where the gap should (I think) be 0.010in a 0.009 feeler selection should not "drag". Again from memory, feelers over double the correct size can be easily forced through the correct gap.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[peter scott]

Horrible thought! I don't suppose one of your seats is dropping out of the head? It was just the push rod popping out that made me wonder.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[baconsdozen]

Might be an idea to go back to basic and do a compression test.That should rule out (or maybe rule in) a dropped seat,sticky valve or blown head gasket.
_________________
Thirty years selling imperial hand tools for old machinery(Now happily retired).

[Jim.Walker]

[peter scott]

[Bitumen Boy]

[Rick]

[Jim.Walker]

Thanks Bitumin Boy!
I have to admit to "coffin-dodging" as I am just recovering from a stroke!
I also admit I am still a little confused and retaining the whole of your lengthy post in mind while adding to this thread was rather difficult at the time.
I have another loss of recall at the moment. I do not THINK you mentioned which Herald model and I cannot recall whether the Solex Carb. models had a hot spot between the manifolds. If yours does have it is worth checking for burning through.
I will sign off while I can still remember my name.
Jim.

I have just re-read your post and see it does have a Solex carb, so is probably a 1200 model.
Also looking back I see I am ridiculed for greasing trinnions on my Gentry/Vitesse. My late wife's Herald is parked outside with almost 100.000 miles on the clock. Those trunnions have only ever been greased too and never failed. Am I doubly lucky or have I used more suitable grease than some? Or could the fact that the steering lock has been reduced to relieve the massive strain on the trunnions have a bearing? No pun intended.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[Kelsham]

I think you should consider an anger management course .

Many of us are coffin dodging. Perhaps you should place an age limit on your enquiry banning replies from the older people on the forum?

Oh of course that is what you have effectively done. Why don't you man up and apoligise.

We coffin dodgers are a relaxed group and most will overlook the outburst.

I won't offer mechanical advice as I am approaching seventy.

Regards Kels.

[Jim.Walker]

Maybe I should do the same Kelsham. I have left 70 behind me.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!