Mark H
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 posted on 27/5/03 at 10:00 PM |
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XFlow only fires on two cyls
Hi Guys,
My XFLow locost has been on the road a week, when the accelerator cable stuck "open" and blew the head gasket, and bent an exh valve.
I have put it all back together, but have one problem left - The engine is only running on two cylinders (3&4). Those two are as sweet as nuts.
The other two are receiving petrol in via the webers but not igniting.
You can take the lead off the plug and there is no discernable difference. You can also cover up the weber on that side, again with no difference.
Head is ok. Cleaned it and all seems ok. Back together with a new valve, head gasket and so on. The problem is not to do with my new valve - its on
the other side of the engine.
We've checked the following:
Spark plugs
Leads (working and in right sequence)
Weber seals
tappets (three times)
Bit perplexed. Any ideas that i can try tomorrow?
Cheers,
Mark
Mark Harrison and
Q986 KCP back from the dead...
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Gizmo
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| posted on 28/5/03 at 12:28 AM |
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Are you sure the linkage between the carbs are OK. 1&2 not working, 3&4 working then the carbs would be most likely.
If it was ignition, then 1&4 and 2&3 would pair the fault !!
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steve m
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| posted on 28/5/03 at 05:17 AM |
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are all the valves moving "up and down" ?
and i know you have checked the leads
but they are on in the right order and the plugs sparking?
as you say that there is no differance connected or not
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Hornet
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| posted on 28/5/03 at 08:20 AM |
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A further suggestion... have you made sure the ditributor was fitted correctly.... is it firing in correct sequence? Perhaps 180 degrees out..
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Mark H
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| posted on 28/5/03 at 08:58 AM |
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Gizmo - We were thinking it was one of the carbs, but nothing "should" have changed since i took them off to get at the head.
I will take them off again tonight, to make sure nothing obvious. They are squirting petrol nicely though? Can the carb be damaged with a backfire
going through them?
Steve - All the valves are moving up and down, as we set the tappets by bringing each valve to the bottom, then guaging the opposite valve (9 rule).
Any alarm bells on this method?
Also, Leads on in right order and plugs sparking nicely (they go in the right order 1243 anyway), but i'll have another look tonight.
Hornet - Dizzy is on the same way round (side exit type cap, so easy to check).
Has any of this extra info rung any more bells, coz unless we get it sorted, i can see this costing me a lot more than pride!
Thanks so far!
Mark
Mark Harrison and
Q986 KCP back from the dead...
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Hornet
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| posted on 28/5/03 at 11:15 AM |
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Soz m8.... exit on cap has nothing to do with it, when you engaged rotor into engine, you could still be out 180. You must ensure its set to fire
cylinder 1 when its at TDC.
Take spark plug out and turn engine to TDC for cylider 1, take dizzy cap of and make sure rotor is at position 1.
If ok.. then thats eliminated. Best o luck
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steve26
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| posted on 28/5/03 at 01:26 PM |
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another suggestion is have you checked for compression on those 2 cylinders? If the head gasket blew then its possible the cylinder head could be
warped. Did it get hot etc? If you don't have a compression tester then just try taking the spark plugs out, put your hand / thumb over the
holes to seal them and turn the engine over. There should be roughly equal compression on 3&4 as there is on 1&2. Another reason for low
compression could be buggered rings or valves not sealing properly??
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Mark H
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| posted on 28/5/03 at 09:27 PM |
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Right, another night on the engine - no nearer.
I printed all the suggestions off at work, and went through each one!
Swapped webers over, problem didn't move, but eliminated a nagging doubt.
thanks Hornet for the abc on dizzy cap (honestly just what i needed - not a mechanic - if you haven't guessed!). Did as you said - timing is
right though.
Stuck fingers in plug holes - seem the same, but tomorrow, i will get meself a tester and do it a bit more scientifically, and will strip the head
(feck it) and check each valve again. If this doesn't work when i get it back together i will be well naffed off.
Can overtightening the head bolts (i have got a torq wrench however) cause this problem? I think i will get someone to look at the straightness of
the head some more, too.
Cheers for your replies so far!
Mark
Mark Harrison and
Q986 KCP back from the dead...
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D Beddows
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| posted on 28/5/03 at 10:25 PM |
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mmmm, I'm wondering how only one valve got bent - with crossflows if you over rev them valve bounce is the first thing that tends to happen
(especialy with standard old? valve springs) and then you can write valves off rather quickly especialy if the block has been decked or if the cam
timing is wrong. I take it there were no marks at all on the top of pistons 1&2?
Even so my bet is you've bent valves on cylinders one and two and therefore don't have enough compression to ignite the mixture - but then
you shouldn't realy have been able to blow a head gasket just from over reving the engine for a few seconds (?) either so......... doubt
it's rings as you probably would have noticed score lines in the bores as it would have to have been a fairly sudden dramatic failure, as Gizmo
said it's very unlikely to be ignition and apart from that with a crossflow there is very little else it could be if it worked before, the
valves and pistons still both go up and down and the plugs and leads all work
Good luck
[Edited on 28/5/03 by D Beddows]
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Hornet
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| posted on 29/5/03 at 07:27 AM |
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If you are not mechanical minded..... I still have another point to ask.... when you checked cylinder 1 was at TDC and rotor was set to fire...... are
you sure cylinder 1 was on compression stroke and not exhaust stroke? (Please ignore this if I am being too basic) FYI a 4-stroke has the
following.. induction... compression.. combustion.. and exhaust strokes ,so you have to be sure when checking for firing that it is on compression
stroke...
PS How is the engine starting? I would have thought it would be very difficult to start a x-flow on only 2 cyliders.... especially the ones that
you say are ok?
Hope you get it going... you will be at frustration stage no doubt ! :mad
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D Beddows
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| posted on 29/5/03 at 02:29 PM |
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That's a good point actualy....it's not too difficult to start a 4 cylinder engine with points type ignition with only three cylinders
firing but if 2 are out it's quite a feat!!!
If the timing was 180 degrees out the engine wouldn't start at all and would backfire through the carbs so that must be near enough. We're
assuming it's points ignition or a basic electrical equivalent by the way?
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ned
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| posted on 29/5/03 at 03:22 PM |
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similar, but not....
once did a head gasket on a metro and put the plugs leads back on wrong it started and ran, though wouldn't rev and kept backfiring.
probably not a great deal of help, sorry...
Ned.
beware, I've got yellow skin
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Mark H
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| posted on 29/5/03 at 06:04 PM |
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Compression Test Results:
Hello,
Mrs H here,
The hubby has just sent me in to type out these results from the comprssion test:
4 = 150
3 = 145
2 = 110 ish
1 = 150
He says he's going to regrind the valves (especially in "2" .
Theres nothing obviously wrong.
Any new ideas would be gratefully appreciated, he says.
And also does any one know what the compression should read from a 1660 X/flow.
Thanks everyone.
Mrs H (and Mark)
Mark Harrison and
Q986 KCP back from the dead...
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Danozeman
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| posted on 29/5/03 at 07:36 PM |
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From them results id say a valve on no 2 was slightly bent.. Which i doubt a re grind would solve.. Aslong as the compressions are roughly the same
on each bore the values dont really matter too much..
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Mark H
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| posted on 29/5/03 at 09:51 PM |
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Well stuff a feather up my arse and call me Daphne...
After the compression test, and a can of lager, the engine now appears to work on all cyls?!?
I'm not one to believe that engines and the like can sort themselves out, but perhaps it cleared its throat or something?
The carbs need settign up, but they did before this whole episode started.
I am sure that i need to take the valves out again, but i think i will run it for a week or so, and see howe it is.
What do others think of this idea, and can engines mend themselves. We have done nothign apart form the compr. test on the engine tonight, then
started her up...
Whatever the outcome, i really appreciate the replies and u2u's. This is what makes this forum so excellent. Cheers. Pints on me!!
All the best,
Mark.
Mark Harrison and
Q986 KCP back from the dead...
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Metal Hippy
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| posted on 29/5/03 at 09:55 PM |
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Pint of coke for me mate, I'm driving....
I know I've contributed absolutely nothing of help to this thread, but I still thought I'd take up your kind offer....
Cock off or cock on. You choose.
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Hornet
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| posted on 30/5/03 at 08:50 AM |
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Are you sure it was lager.... maybe it was Red Bull and you spilled some on the engine..
Nice one.. glad its going. 
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MikeRJ
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| posted on 30/5/03 at 09:36 AM |
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quote:
Originally posted by Mark H
Steve - All the valves are moving up and down, as we set the tappets by bringing each valve to the bottom, then guaging the opposite valve (9 rule).
Any alarm bells on this method?
Yes, bells are ringing furiously. I think the crossflow has the same firing order as the Valencia engine (1243) which is different to just
about every other 4 cylinder engine I have ever worked on (1342).
I set up the valve clearances on my g/f's Fiesta using the rule of nine method. I always go back and check the clearances after I have set
them, and in this case they were all over the place. Looked in the Haynes manual and they showed a different technique which I can't totaly
remember. I think you set one pair of valves rocking, and then set the opposite pair, e.g. no. 1 rocking, set no. 4. At work at the moment but
I'll check later.
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steve26
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| posted on 30/5/03 at 09:55 AM |
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Alright Mark, glad 2 hear the problems sorted!! Must be a relief!
Its possible there was a bit of crap stuck between the valve & its seat - now dislodged!?!?
Anyway...who cares - congrats mate!!
p.s. What's the secret of getting the other half 2 help out????
Latas, DS
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Mark H
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| posted on 30/5/03 at 10:37 AM |
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quote:
Yes, bells are ringing furiously. I think the crossflow has the same firing order as the Valencia engine (1243) which is different to just about every
other 4 cylinder engine I have ever worked on (1342).
Thanks MIKERJ - the firing order IS 1243. We did try the 1/4, 2/3, 3/2, 4/1 method first, but wasn't convinced!
In about 50 miles or so i will be retorqing the head anyway, so tappets will need redoing. Anyone got the cast in stone method of ensuring tappets
are perfect on the XFlow?
Reagrding the other half helping, i think it was in between Eastenders and Bad Girls!
This week the only time she has seen me is to shout my dinners ready, pass me a lager, or to do my Locostbuilders administration. Poor thing (or
perhaps she's been lucky!)
Mark
Mark Harrison and
Q986 KCP back from the dead...
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James
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| posted on 30/5/03 at 10:53 AM |
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quote:
Originally posted by steve26
p.s. What's the secret of getting the other half 2 help out????
Latas, DS
Letting them do the interesting bit while you get on with the boring (but still necessary) tasks.
The first time I got my g'friend to help she got to do the grinding and some tack welds.
So they feel they've made a contribution even if you have to re-do it after they've gone!
Saying that though- the last time my g'friend helped I had her filing down the insides and ends of the crush tubes whilst I did the grinding-
not terribly exciting for her but she seemed pleased!
Just treat them the way your Dad did when you were six and he was trying to do DIY- ie. you got a scrap of wood and a hand drill whilst he did the
stuff that actually went on the wall after you'd forgotten about it!
Cheers,
James
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Mark H
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| posted on 30/5/03 at 02:37 PM |
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Helping out!
Hello again,
Mrs H here,
The only reason I help Mark out is so I can appease my guilt when I'm out driving the beast on days like this whilst he's at work.
Mwa ha hah hah hah haaaaaagh!
Mark Harrison and
Q986 KCP back from the dead...
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ned
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| posted on 30/5/03 at 03:06 PM |
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Rock on Mrs H!!
beware, I've got yellow skin
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D Beddows
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| posted on 30/5/03 at 06:50 PM |
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hurrah!!! glad I was wrong mate
Just to leave this topic with one thing... the Haynes Manual way of checking valve clearences is crap as you have to get two valves into the right
position rather than one (and it's much harder to remember than it has to be) - instead - no.1 valve fully open check 8, 2 open check 7 etc
until you get to 4 open check 5 then it's 8 open check 1, 7 open check 2 - ie do it the other way round - very hard to forget and much harder to
get wrong.......then all you have remember is 25 inlet and 55 exhaust on your metric feeler gauges and you can throw the manual away
lol
Dave
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MikeRJ
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| posted on 31/5/03 at 12:22 PM |
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quote:
Originally posted by D Beddows
Just to leave this topic with one thing... the Haynes Manual way of checking valve clearences is crap as you have to get two valves into the right
position rather than one (and it's much harder to remember than it has to be) - instead - no.1 valve fully open check 8, 2 open check 7 etc
until you get to 4 open check 5 then it's 8 open check 1, 7 open check 2 - ie do it the other way round - very hard to forget and much harder to
get wrong.......then all you have remember is 25 inlet and 55 exhaust on your metric feeler gauges and you can throw the manual away
Dave
The method you have quoted is known as the "rule of nine" and works fine for engines that have a 1342 firing order. As I said in my
earlier post, the Kent and the Valencia have a 1243 firing order and this method does not work properly, as the follower is starting to hit the
closing ramp on the cam at the point where you measure it. You won't notice unless you go back and check all clearances whereupon you'll
find they'll never be the same twice.
Haynes describe the "rocking" method because it works properly. If you look at a Haynes manuals for a engine with a 1342 firing order you
will see they describe the "rule of nine" method.
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