She lives ! / X flow timing question ......
Discussion
Well, if you remember, a few months back the X flow in my Westie exploded in a interesting stylee, totally obliterating the engine. As a postscript to that, upon disassembly the reason why it happened is as follows : the cam follower on the inlet valve which met the piston was all broken, so I think the follower broke up, a chunk of the broken metal got between the cam and the remains of the follower, and pushed the valve that little bit too far, resulting in the bang. Interestingly enough, another of the followers was completely snapped off, resulting in huge clearances on that valve. This had happened some time ago, as the cam had worn smooth the "rough" metal on the break (knackering the cam lobe in the process of course). Oh well ....
Anyway, I went out and bought a similar spec engine which had just been taken out of another Westie from a fellow PH member (who shall remain nameless). This engine was sold to me as "good and running", however as soon as I put it in my car it was obvious all was not well ... knocking from the bottom end, a lot of blow past the rings, and blue smoke. Various swear words ensued. So, back out with the engine again (I can now take the engine out of my Westie in 2 hours dead !!
) and off to my local engine specialists, who have replaced / done the following : hone, new rings, new valve guides (2), cam bearings, shell bearings (4 out of the 8 were down to the copper ... VERY badly worn) and a regrind of the scratched crank. I now have a nice fresh tight little engine installed (took all weekend !) which fired up yesterday afternoon for the first time ! Woo hoo !
Which leads me on to my question. At the moment the timing is VERY roughly set, which allows the engine to run, but on a very short trip round the block the engine was wanting to overheat, presumably because the time is so badly out. I'm going to call out a mobile tuners, to set the engine up "about right" so I can do lots of running in miles, before taking her to a rolling road. But what should the timing be on something like this ?!?!?
(engine spec : 1700 X flow, A6 cam, connaught performance dizzy fitted with luminition ignition, twin 45DCOE's, full race head)
Cheers !
Nev
Anyway, I went out and bought a similar spec engine which had just been taken out of another Westie from a fellow PH member (who shall remain nameless). This engine was sold to me as "good and running", however as soon as I put it in my car it was obvious all was not well ... knocking from the bottom end, a lot of blow past the rings, and blue smoke. Various swear words ensued. So, back out with the engine again (I can now take the engine out of my Westie in 2 hours dead !!
) and off to my local engine specialists, who have replaced / done the following : hone, new rings, new valve guides (2), cam bearings, shell bearings (4 out of the 8 were down to the copper ... VERY badly worn) and a regrind of the scratched crank. I now have a nice fresh tight little engine installed (took all weekend !) which fired up yesterday afternoon for the first time ! Woo hoo ! Which leads me on to my question. At the moment the timing is VERY roughly set, which allows the engine to run, but on a very short trip round the block the engine was wanting to overheat, presumably because the time is so badly out. I'm going to call out a mobile tuners, to set the engine up "about right" so I can do lots of running in miles, before taking her to a rolling road. But what should the timing be on something like this ?!?!?
(engine spec : 1700 X flow, A6 cam, connaught performance dizzy fitted with luminition ignition, twin 45DCOE's, full race head)
Cheers !
Nev
Sounds like you shoulda asked for a refund!!!
If its overheating, then the timing sounds like its way too retarded to me.
I dont have any info on X flows tho so i cant give you a figure, but as a guestimate, id say around the 6 to 10 degree btdc mark should be safer than where it is now.
Sorry i couldnt help more.
If its overheating, then the timing sounds like its way too retarded to me.
I dont have any info on X flows tho so i cant give you a figure, but as a guestimate, id say around the 6 to 10 degree btdc mark should be safer than where it is now.
Sorry i couldnt help more.
deltaf said: Sounds like you shoulda asked for a refund!!!
I did, ahem, discuss it with the gentleman concerned however he just said "it was okay when I last ran it". Yeah. Right. So I'm just imagining the chronic blow by and the blue smoke then. Must take some photos of the completely-copper, no-white-metal-left knackered shell bearings and send them to him. No matter. Caveat emptor, plus you live and learn.
then the timing sounds like its way too retarded to me
Quite possibly. Um ... which way is retarted ?!? (doh)
can't you call them
They weren't quite sure what the timing should be ... I did ask them.
shagged thermostat
The thermostat is brand new, but I take your point. I was planning on whipping the thermostat out tonight (I was thinking more along the lines of air 'blockage' somewhere)
Cheers
Lol Nev! Should you be playing with timing lights etc?
Ok, theres 3 things you need to know.
TDC is top dead centre, thats when the piston, usually taken as number 1 cylinder, gets to its highest, just before it starts to reverse, thats TDC.
The spark has to occur BEFORE TDC, so, if youre looking at the front of the engine, pulleys are in front of you, The engine rotates clockwise.
If the spark occurs AFTER TDC, (piston going back down) that means that the ignition (spark) is happening late, far too late. Retarded condition.
Converseley if the spark occurs as the piston is heading UP the bore towards TDC (both valves closed ) and the spark occurs at some point before it gets to TDC, then thats an advanced condition.
ALL engines have to fire BEFORE TDC, hence the term 10 degrees BTDC (before top dead centre).
It gives the fuel/air mix time to burn and start expanding before pushing the piston down the bore.
There should be some form of marking on the crank pulley, a pointer on the engine.
Hope this helps.
Ok, theres 3 things you need to know.
TDC is top dead centre, thats when the piston, usually taken as number 1 cylinder, gets to its highest, just before it starts to reverse, thats TDC.
The spark has to occur BEFORE TDC, so, if youre looking at the front of the engine, pulleys are in front of you, The engine rotates clockwise.
If the spark occurs AFTER TDC, (piston going back down) that means that the ignition (spark) is happening late, far too late. Retarded condition.
Converseley if the spark occurs as the piston is heading UP the bore towards TDC (both valves closed
) and the spark occurs at some point before it gets to TDC, then thats an advanced condition. ALL engines have to fire BEFORE TDC, hence the term 10 degrees BTDC (before top dead centre).
It gives the fuel/air mix time to burn and start expanding before pushing the piston down the bore.
There should be some form of marking on the crank pulley, a pointer on the engine.
Hope this helps.
Just coz I couldn't remember my advanced from retarded (maybe it's me who's the retarded Nev,
6 - 10 BTDC sounds like a good starting point, but I would contact Kent or Piper cams and ask their advice. My old Xflow was found to be best set at 14 degree BTDC!!
Timing can cause over heating but this sounds a little more serious, have you checked the water ways?? Air lock sounds likely.....
Good luck,
Mark B
6 - 10 BTDC sounds like a good starting point, but I would contact Kent or Piper cams and ask their advice. My old Xflow was found to be best set at 14 degree BTDC!!
Timing can cause over heating but this sounds a little more serious, have you checked the water ways?? Air lock sounds likely.....
Good luck,
Mark B
nevpugh308 said: Mark ... thanks for the (possible) timings. Need to get hold of a cheap timing strobe ... my local Halfords do one, but only for £75 !!! S*d that !
Overheating : I'm going to whip the thermostat out, and try and make sure there's no air in there. Cheers
Timing light won't help apart from set it at whatever you decide. You need to ring Piper or Kent first and find out what is recommended by them......
Re the overheating, I never had a thermostat in my Sylva, just a blank plate with small hole drilled in to restrict flow of water?? I assume you have a decent header tank?? make sure the engine is running without thermostat and fill it up from the header let air escape wherever you can...
Mark B said: [Timing light won't help apart from set it at whatever you decide. You need to ring Piper or Kent first and find out what is recommended by them.....
The cam manufacturers are most unlikely to be able to give a number any more accurate than already given in here. There are far more variables than just the cam that affect ignition timing.
If the timing was set so badly retarded that it was overheating then the OP should have been able to feel the lack of power and general unwillingness to rev, even if it is being carefully run in.
MR2Mike said:
Mark B said: [Timing light won't help apart from set it at whatever you decide. You need to ring Piper or Kent first and find out what is recommended by them.....
The cam manufacturers are most unlikely to be able to give a number any more accurate than already given in here. There are far more variables than just the cam that affect ignition timing.
If the timing was set so badly retarded that it was overheating then the OP should have been able to feel the lack of power and general unwillingness to rev, even if it is being carefully run in.
Nope, it ran like a dream, and didn't even need to turn over once to start. I mean, I didn't take it over 3000 rpm of course, but it was more than happy to run.
Maybe it is/was an air block then ....
Just been looking in a Haynes Manual for causes of overheating*
"Engine not yet run in" was one of them.
In view of
hone, new rings, new valve guides (2), cam bearings, shell bearings (4 out of the 8 were down to the copper ... VERY badly worn) and a regrind of the scratched crank. I now have a nice fresh tight little engine installed
Could this be the problem?
How many miles have you done?
A mobile tune up might be a good insurance policy!
*It was a Haynes Manual for a Fiat Panda...but hey an engine's an engine!
"Engine not yet run in" was one of them.
In view of
hone, new rings, new valve guides (2), cam bearings, shell bearings (4 out of the 8 were down to the copper ... VERY badly worn) and a regrind of the scratched crank. I now have a nice fresh tight little engine installed
Could this be the problem?
How many miles have you done?
A mobile tune up might be a good insurance policy!
*It was a Haynes Manual for a Fiat Panda...but hey an engine's an engine!
denhay .... ah, interesting thought. The engine has barely got 50 miles on it now, and I KNOW it's still fairly tight as the tiny race battery struggles to turn it over from cold a bit.
The engine is still .... well, I wouldn't say overheating, but the temperature is fluctuating lots between 90 degrees and 105 degrees whilst driving (I'm limiting myself to 3000 rpm at the moment, btw).
I've replaced the water pump (which had decided to start dripping anyway) and that made no difference. I've played with the engine timing between 2 deg and 10 deg BTDC and that made no difference either.
I dont think it's the temp gauge or sender because the oil pressure varies in relation to the temperature, i.e. when the engine gets hot, the pressure drops a bar or so (i.e. the oil gets "runnier" .... I'm only using a cheap oil for the running in period)
I took the (new) thermostat out completely, and that helped loads, but did severly over cool the engine (70-80 degrees). I've dug out an old thermostat which I will pop in tonight, OR I might try the old trick of ripping the working guts out of the thermostat, and just put the blanking plate with hole in the housing (i.e. effectively an "always open" thermostat, but coolant flow is still restricted through the plate)
The other odd thing is that the temperature variation seems to happen VERY suddenly, i.e. one second it's 105, 2 or 3 seconds later it's dropped to 90 ...
The engine is still .... well, I wouldn't say overheating, but the temperature is fluctuating lots between 90 degrees and 105 degrees whilst driving (I'm limiting myself to 3000 rpm at the moment, btw).
I've replaced the water pump (which had decided to start dripping anyway) and that made no difference. I've played with the engine timing between 2 deg and 10 deg BTDC and that made no difference either.
I dont think it's the temp gauge or sender because the oil pressure varies in relation to the temperature, i.e. when the engine gets hot, the pressure drops a bar or so (i.e. the oil gets "runnier" .... I'm only using a cheap oil for the running in period)
I took the (new) thermostat out completely, and that helped loads, but did severly over cool the engine (70-80 degrees). I've dug out an old thermostat which I will pop in tonight, OR I might try the old trick of ripping the working guts out of the thermostat, and just put the blanking plate with hole in the housing (i.e. effectively an "always open" thermostat, but coolant flow is still restricted through the plate)
The other odd thing is that the temperature variation seems to happen VERY suddenly, i.e. one second it's 105, 2 or 3 seconds later it's dropped to 90 ...
Sounds like airlocks or cavitation causing sender to see hot steam/cooler water intermittently. I had same symtoms in a TVR 350 wedge which overheated unless the heater was on which seemed to cure the problem at the expense of the passengers if the roof was up. Try drilling a few holes around the edge of the thermostat plate to allow a bit of flow but not enough to overcool before stat opens fully.
sounds like a dodgy gauge/wiring to me
go and get a cheap multimeter with a thermostat and check the actual water temp . . . .I got one for about £15.
a good trick to control water flow is round the top hose with a jubilee clip . . . .tighter restricts flow, looser lets it go, that should cost about a pound for an infinitely adjustable cooling system !
go and get a cheap multimeter with a thermostat and check the actual water temp . . . .I got one for about £15.
a good trick to control water flow is round the top hose with a jubilee clip . . . .tighter restricts flow, looser lets it go, that should cost about a pound for an infinitely adjustable cooling system !
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