David McHugh
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Posts posted by David McHugh
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Yes, that is what the cams should be doing. No.1 both closed as piston is TDC while No.4. also approaches TDC and the valves are both slightly open. This is so reliable that is you have the means to measure their opening (dial gauges) it is s simple method of setting the cam timing, called Equal Lift On Overlap. (The overlap is of the two valves being slightly open at the same time) As you are using it, it is also a useful way to check that the cam timing is correct.
You mention that you get consistent blow back when you use some 'Easy Start'. This make me wonder about your ignition timing, given that the cam timing is OK. Look under the Dizzie cap, with No.1 at TDC and both valves closed. This is the start of the ignition/power stroke, when the spark plug should fire. Is the rotor arm pointing at No.1 terminal?
Then, have you installed the plug leads in the right order 1-3-4-2, going ANTI-clockwise?
If all these are true, then try starting the engine with the dizzie slightly loose, so that you can turn it by hand, a few degrees either way, until it catches.
Mark the dizzie in some way so that you can return it to the original position easily, and not get lost!
John
Hi John,great we are thinking along the same lines, what you have suggested is what my Dad said except you have explained it far better, so thanks once again.
It probably won't be today but I will try your method in the next couple of days.
Happy New Year to you John
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when you say rebuild was that the car or the engine ?? was the engine stripped and rebuilt ??
has it run ok in the past .. whats been done to upset cam or ignition timing
Pete
Pete, thanks for the reply. The engine has been completely stripped down, so the timing chain has been off and the camshaft out. When I put it back together in checked that I had aligned the timing markers. I have had the engine in pieces before and rebuilt it and hado it on the road after without any problems.
David
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David,
Fully agree with Mjit, good explanation. I'd add:
No suck at the carbs, "when you put your hand over the air intake of the carbs"? There are, as you know, two carbs! And a 'balance pipe' between them, so you need to block both at the same time.
Difficult to do that, and turn the engine, unless you have recruited an assistant.
It's difficult too, to feel the compression strokes as you turn the engine by hand, as there is always one cylinder doing it, but take out a spark plug and block the hole with your finger. You may be able to feel it, or hear the gas escape when you take it out. Or, take them all out bar one and feel that as you turn it. If your cam timing (not to be confused with ignition timing) is out, then there may be no compression. If you have a compression gauge, that will read very low across the block.
Of course you may need some of this:
John
John, Thank you for your reply too.
I did check only one carbs with my hand over the intake while turning over with the key not by hand, I thought it would be enough. Covering both carbs is something I can try.
As for cam timing, this is where I originally thought the problem my lie, this was why I have checked that the valves on no4 are doing what the manual said they should be doing ie. as no1 comes up to tdc no4 exhaust valve should be closing and the inlet value should be opening, if this is happening surely that means the cam timing is correct? It would help to know what stage the valves on no4 should be at tdc, this would be more accurate.
I have a compression tester but have not tried it because I didn't think that the engine being turned on the key would be fast enough to get a reading.
I will try the compression tester, if it doesn't work, I will try my finger in a plug hole with the rest in place. Sorry to say I didn't understand what you meant by taking all but one plug out and then??
Thank you to for the video clip, very funny lol
David
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The cycle is suck/squeeze/bang/blow.
For suck you want the inlet valve to be open, so the fuel/air mix can get in to the cyclinder.
For squeeze you want everything closed - if either the inlet or exhaust valves are open the rising piston will just push everything back out the cylinder via that valve.
For bang you also want everything closed - if either valve is open it will be easier for the gases to exit the cylinder that way, rather than by pushing the piston down and turning the crank.
For blow you want the exhause valve open so the rising piston can get the spent gases out, before swapping exhaust and inlet valves as you go over TDC and back in to suck.
So it sounds like things are broadly right on the timing front. As #1 approached TDC with both valves closed (squeeze) the rotor arm approaches #1 plug lead. Mean while #4 is at the other end of the cycle, approaching TDC on the blow (exhaust open) and moving in to suck (inlet open).
All that said nothings going to work if you're not getting any fuel - and even if you were times 180 degrees out you should still be getting suck through the carbs.
- Are you getting fuel to the carbs? Crank for 30s and check you have fuel in the float chambers. If you don't check back towards the tank to work out why.
- If you do start with the jets flush with the carb body and screw then down 3 turns. That low fuel should just bubble through. If it doesn't start unscrewing the pipe from the float chamber to the carb. Fuel should starts leaking and it suggests the pipe is blocked (and if there's fuel in the float chamber and it doesn't leak you're breaking the laws of physics!).
- Have you checked your rocker gaps and are they actually going 'loose' when closed. If not the exhaust valves could not be closing fully, so you'd be sucking air back past them rather than fuel/air through the carbs/past the inlet.
- Grab an assistant and a can of Easy Start. Get them to crank the engine and squrt Easy Start directly through the carbs. That should get some caughing and spluttering (and maybe a little back-firing so keep your eyebrows clear) if nothing else.
Mjit, thank you for your response. I understand the 4 stroke cycle of suck, squeeze, bang and blow, however I failed to run through the sequence to understand why the Haynes is telling me to check the valves on no4 and not no1 when bringing no1 to tdc.
I have adjusted the tappets but I have not checked that they are going loose when closed. I will do this as my next step.
I have got fuel in the carbs, that was my first check.
I have tried Easy Start, I don't get any firing just a blow back through the forward carb, this happens after turning it over for about 3 secondseries and seems to be consistent.
I think I have covered all of your points, thank you, I will check that the valves are actually going loose when closedo, as my next priority now to John's reply.
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Hi all, once again your expertise help is sort.
1973 Spitfire IV 1300cc
Following a rebuild I am not getting fuel to the plugs, in fact the carbs are not suckling when placing my hand over the air intake of the carbs. From the tests I have done,it am pretty certain that it is a timing problem. The Haynes manual says that in order to check if the rotor is 180 degrees out. When turning the crank to bring no1 to tdc no4 exhaust valve should be closing and the inlet value should be opening, however it would be more logical to me if this was happening at no1 and not at no4 as it is no1 that is at tdc, likewise the rotor is pointing to no1.
In a case where I am not 180 degrees out, could it be to do with the distributor adjustment ? I am setting no1 at 8 degrees btdc with the rotor directly central to the no1 terminal in the distributor cap, is this correct? or should it be that the rotor be just on the leading edge of the terminal?
All comments, recommendations etc will be appreciated.
Best wishes
David
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Hi Steve C,
I am in the process of yet another block rebuild and wondered what you thought of my idea, when complete use a diesel engine oil to run the engine (car stationery) for say ten to 20 minutes at about 2000 reves, drain itand replace with Halford classic and follow your regime of 50/250/500/1000/2000.The reason I thought of using the diesel oil first, is to try to remove the sludge that gets stuck on the internal surfaces. I have removed what I can but feel that a wash out with diesel oil will get to the places I was unable to reach.
I would value your and anyone else's thoughts / comments on this.
Thank you in advance,
Kind regards
David late 1973 Spitfire IV original 1300cc
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Hi Dave
It can also be about the type of driving you do. Oil works best when stinking hot, which is why cars which live on motorways tend to be able to go on to high mileages before they need a rebuild, while the same model that has only ever done short sharp trips can need one at 70k. The best favour you can do your classic is to take it on a motorway once in a while.
Like you I am a disciple of regular oil changes, more often than specified. Oil is cheaper than engines, and manufacturers have a vested interest in being able to cite low running costs. Tribology has improved tremendously with modern synthetic oils, and they don't break down in the way the mineral oils our cars were designed for do. I have always been a GTX (latterly Halfords Classic) user, and have never been tempted to put modern oils in, although I know some members swear by them.
I also think how an engine is run in can affect its lifespan. All my rebuilt engines have had 50/250/500/1000/3000 mile oil and filter changes. Some would call that excessive, but they have all run to very high mileages, and I have always been surprised at the crud that comes out on the first couple ofl changes!
Regards
Steve C
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Hi Guys, my Spitfire IV failed it's MOT, one of the things is "Brakes imbalanced across an axle rear" can anyone please tell me what, apart from a faulty cylinder, would cause unequal braking pressure between the back Wheels?
If it is a cylinder is it likely to be obvious which one it is or for the sake of £10 is it just best to change both?
Thank you in advance for your help.
David
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John and Pete, wow so much information. Thank you guys for your time spent on providing me with some great possibilities. Due to the complexity of fettling a head I have ordered a book,
How to Build, Modify & Power Tune Cylinder Heads by Peter Burgess & David Gullane. I do actually have a spare engine, so have a head to play around with, I think this is a job that is going to take me some time so ha email put my head back on the car so that I can use it.
Using the other head and the book when it arrives I will have a go at tuning òver the coming couple of months and will let you both know how I get on.
Kind regards
David.
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I was going g to suggest flowing the head, ducts and chambers, and a skim to raise the CR. But you don't want that? Just a skim then, Sir? Will have a lesser effect but simply and safely done, if you calculate how much, not go by a magic number.
John
John
I do actually like the sound of increasing the compression, while I understand skimming the head, I don't understand what you mean by "flowing the head, ducts and chambers," I would be greatfull if you would elaborate.
Kind regards
David -
Thank you for your replies.
The head has been converted to unleaded, I put in new cam followers when I did a partial rebuild at the same time I upgraded the cooling pipe that Richard referred to with stainless steel and Pete, I did change the filters but once I get some flexible hosing I will put the original back. I have also purchased the radiator and engine side panels.
Going back to the head, I was wandering if it is worth replacing valves and springs those sort of things? I have no intention of tweaking as Pete said it can lead to problems.
Kind regards
David
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Hi Simon, when you first heard the sound did you ask what it was or did he offer any kind of reason or any comment about it? I appreciate that you don't have the experience but he didn't know that, had it been me selling it with a sound that is quite obviously not supposed to be there, I would of offered an explanation. I find it very odd if he did not react in some way when the sound started.
I think you made the right decision to walk away.
Kind regards
David
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Hello to All,
While I have the cylinder head off, I am looking for ideas/suggestions for what I can do to it that will be beneficial, I thought of either putting new valves in or grinding in the existing, incase there are any signs of carbon build-up, however I don't know if this is worthwhile or not.
Your thoughts and comments on the above and on other things that I can or should do that is beneficial, will be greatly appreciated.
Many thanks in advance.
Kind regards
David
Spitfire IV '73 1300cc French Blue
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You need to release the clamp(two bolts) at the bottom of the cover that holds the column then the cover just lifts away from the location point at the top.
Thanks Ben, really appreciate it. David
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Hi chaps,
Does anyone have any ideas, how to remove the cover plate on the underside of the steering columb that hides the wiring? I have tried to unclip it, that does not seem to be the right way. I have also tried to slide it as there is a hole in the top, it wiĺl not move.
Any help would be much apriciated.
David
Spitfire IV '73 French Blue.
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Hi can anyone recommend a outdoor waterproof but also breathable cover for my MK IV Spitfire.can anyone recommend from the TSSC shop or other source, it will get a bout 3 to 4 months use a year and will be removed on summery days to get a good airing.
Your recommendations are greatly appreciated.
One other thing is dehumidifier granule bags that can be recharged by heating in the microwave. The one I bought from Robert Dias is useless the only part that soaks anything up is the bag not the contents, your experienced help would be greatly received in this matter too.
Kind regards
David McHugh
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Thanks guys, I am somewhat relieved that it is most likely the prop and not the differential. The reason I thought it might have something to do with the differentiial was the slight knocking sound I get when pulling away. The biggest problem I have is living on Portsea Island, I have to drive five miles to get to somewhere that I can drive fast enough to test any alterations that I make, I guess it's going to take a while. When I first looked at the strap drive, the straps were not put on evenly as well as having the jubilee clip, un fortunately I don't know if the straps were changed on purpose to try and rectify vibration, not that it really makes any difference since correcting the straps does not seem to of made any difference.
If I was to have the prop balanced or buy a balanced one, would it be a case of just fitting it once , or does it have to be tested and turned 90 degrees at a time until the drive is smooth?
Thanks again for all the comments which are most helpful as usual.
David...
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Hi All. Since I bought my Spitfire IV 74, I have had quite bad vibration at the rear-end and a slight clonking as I pull away. I did discover that the rear end of the prop shaft was not connected correctly (metal strips not even) I corrected this and removed a jubilee clip that had been placed around the rear of the prop shaft. I have checked all the universal joints for play, none found but I have replaced the radius arm bushes and there is no uneven ware on the tyres. There is some play on the off-side out-put shaft and the wheel bearings are all okay. I can't say that I have noticed any difference in the vibration on the overrun.
I really don't know what to do next, I would imagine removing the diff is not a particularly easy job so I thought perhaps changing the input/output bearings would be the next step? Are there any other things I can do without having to remove the diff from the car?
Your thoughts and ideas would be greatly appreciated
Kind regards David.
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it's okay i have sorted it out, thank you for your help guys.
All the best
David...
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Thanks for the help guys. I have established that i have a wiring issue which of course leads to another question. about the earthing of the coil. I installed electronic ignition which requires removing the coil neg to distributor and adding the electronic module that sits in the distributor and is wired across the coil ie. red to + and black to - , so my question is how is the coil now earthed? is it a case of simply adding another wire to the - on the coil and the other end to metal ?
Your help is much appreciated as usual
thank you in advance
David...
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Hi Guys, I am hoping that someone can give me some answers.
I went to start the car and all I got was a click from the solenoid i guess, i got a second hand starter, on the first attempt it turned the engine very slowly and when i tried a second time, all i got was a click the same as my original starter. I presumed the second hand starter was faulty so i exchanged for another used one. I fitted the started tried to start the car and it was turning the engine over without any problem (car usually needs several attempts to start) it didn't start first time, turned the key again and CLICK, not even an attempt to turn over just click the same as with my original starter.I am baffled, surely its not frying the starter motors, no wiring has been changed. The battery is showing 12.65 V and while turning the key it drops to 12.32 V so i don't see a problem with the battery.
Any help will be greatly appreciated.
Thank you in advance David...
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Hi guys, I want to fit an oil cooler to my 1974 Spitfire IV 1300cc, I am struggling with what thread sizes are correct on the cooler sandwich. I realise the ports need to match the hoses and fittings which I believe should be 1/2 inch (please correct me if wrong) but it is the thread that connects the sandwich to the engine or to be presise to where the oil filter fits.
Your help is greatly valued as always, kind regards
David...
BTW, intention is a 13 row cooler with thermostat, thoughts on size, appreciated .
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Thank you once again Pete.
All the best
David...
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Hi Guys,
According to the Haynes manual for the 1300 Spitfire engine, the timing should be set to 8 degrees BTDC.
I would like to hear your thoughts on this with modern fuels, is this still a good indicator?
Thank you in advance.
David...
Timing 180 degrees out ???
in Engine
Posted
Pete,very well explained, now that I have all the answers for what I was looking for thanks to John and yourself, i am just waiting for a slightly warmer day to implement the checks and adjustments where needed. It's not nice handling metal for hours in 2 to 4 degrees.
Happy new year to you Pete.