Andrew's Mk IV Spitfire

[egret]

Given the drift on the few threads I've started with specific questions on my car I thought I should start a dedicated thread for what I'm doing on car. 

Summary so far is:

Polybushes added almost everywhere.  I've used a mix of red and blue to try and keep it from being too crashy.

Lowering springs from D Faulkner springs. 2.5 Inch ID 9 Inch Free Length 320Lbs spring rate

Lowering block at the back 1"

Braded brake lines.

Replica minilite alloys.

Electric fan with thermostat.

Re-built FD mk3 1300 engine, standard block.

Bigger valve head with a 9.5:1 and a bit of valve fettling. 1500 manifold with twin HS4 SU Carburettors.

Megajolt ignition.

Tubular SS exhaust manifold. Stainless exhaust into carbon motorbike backbox (a nostalgic relic from my CBR600FX)

Various usual brake overhauls, synthetic gearbox and diff oil, new trunion bushes, etc. etc. etc.

 

I've been chipping away at a few projects to get it running properly.  Megajolt is hopefully almost ready.  I ended up waiting for a replacement chip in the hope that I could swap out the fried one, but after a couple of false starts, I've given up on that, so I'm putting in the new(er) megajolt I bought from ebay.  Only problem is that this was set up for TPS, so I've swapped the MAP sensor off the old megajolt onto the new one, and hopefully will get that re-programmed with a reasonable ignition map, and tell it to use the MAP sensor rather than TPS.

While this has been going on I've put together the air intake system, which I've been collecting parts for for years.  Even so it's still a bit of a prototype as the plenum needs revisiting, and holding it in place with zip ties is not a permanent solution.  I had a clamping failure when bonding the aluminium together.  Somehow didn't manage to weigh it down evenly, so I think I will need to grind/file off the adhesive and re-apply.  The gap is bodged at present, but tested watertight.

I will say that despite my clamping issue, MMA (methyl methacrylate) adhesive is rather good.  No need to prep aluminium, goes on like silicone and cures to handling strenght in 12mins with working strength in 30min.  So work fast and make sure you have spare mixing nozzles, but it's really good stuff!

So don't look too closely at the airbox, but the design principle is to maximise plenum volume in the availible space inside the wheelarch, then use large bore tube to connect to an oversized air intake filter in front of the rad.

Other advantages are that I'm not fiddling with multiple components and gaskets everytime I want to take the airbox off to check the carbs, and I have some 3-d printed low profile velocity stack to connect inside the airbox to smooth out the transition too.  This is another future addition as they need a bit of fettling.

The goal now is to confirm the mejaolt works, then get it booked onto a rolling road to refine the ignition map and get the needle selection right.

I'm happy to hear any comments, or warnings, on the design or execution of the inlet manifold system.  N.B. the plywood deflector in front of the radiator is a placeholder, and I'm aware that some of the fabrication is a bit ropey, but it should be good enough to get me out driving the thing!

[egret]

It works! Megajolt behaving and it revs a lot more freely now.  Fueling is not great now though.  I think the carb jets and needles need a clean as I couldn't get the thing pulling right.  Enough glimses of performance to get me excited about it when it's properly sorted, and enough for me to be happy to book it into the rolling road and even signed up to the Stilton Cheese run on the 21st April, which seems like a fairly relaxed run out and relatively local.

[RichardB]

The smoothness added by the megajolt is wonderful isn't it. I like your air intake idea, its a bit tricky getting cold air into the engine despite the generous under bonnet space.

[egret]

The rolling road is booked for a months time.  They are booking 6 weeks in advance, and came from a recommendation so I'm optimistic about the results.  However the spitfire doesn't seem so excited as it refused to allow me to even put the key in.  The ignition barrel all but gave up on me a week ago with the symptom of the key not going into the ignition.  It's worn to a point that the no1 tumbler pin comes out too far and almost falls out, it wedges in the keyway so that the key won't go in.  Took a while to work that one out!  Eventually I managed to get a look at the correct angle and poke it back into it's pocket with a multimeter probe and then slip the key in. 

So next job is to try and get a replacement ignition barrel and swap it out.

 

[egret]

Took a trip to the local tssc meet last night, and the guys were all very helpful. Confirmation that something is off with the fuelling, and the discovery that there is quite a rattle that's most probably the timing chain I re-used. I put a new tensioner on, despite the warnings here as the old one looked pretty worn. So I need to get the timing cover off and investigate.

Fuelling issue seems like it might be worn jets or needles.  Need to have a look at that too.

Dyno clock is ticking...

Edited April 9 by egret

[RichardB]

The ignition barrel issue sounds like a bit of a pain. One of my small goals is to one day be able to open all locks on the car with one key, rather than having one for ignition, bonnet lock, boot lock, door lock and locking fuel cap. Ive heard its not terribly difficult to change barrel pins to get a matching set. Hopefully you don't end up in the same situation with your barrel.

[egret]

A new barrel and chain kit are on order.  I think I might try and get the chain cover (and tensioner) from the 1500 on the 1300.  It's got a graduated pointer on the front, so I should be able to measure static timing with my dumb timing light.  Fingers crossed I can get it sorted this weekend, but the garage has been re-purposed as a temporary store room while spitfire was out and about, so there's sorting to do.  That or I brave the elements. The weather gods look to be kindly at the moment, but with all the wind that can change very quickly!

[Escadrille Ecosse]

On 4/8/2024 at 9:13 AM, egret said:

However the spitfire doesn't seem so excited as it refused to allow me to even put the key in.

Innate hostility of inanimate objects

12 minutes ago, egret said:

I think I might try and get the chain cover (and tensioner) from the 1500 on the 1300.

If you have an FD engine with the small bearing crank, the later timing cover unfortunately won't fit as the oil seal is larger diameter to suit the larger bearing cranks of the later 1300 and 1500s.

[zetecspit]

Tony Lindsey Dean has had some uprated chain tensioners made because of the issues with the ones being sold everywhere else. 

A local vitesse owner had a tensioner fail in a few hundred miles, he was not happy. He found the old one and reused that. 

[Nick Jones]

https://www.chriswitor.com/proddetail.php?prod=145866HD
 

Not sure if 6 pot duplex fits 4pot small-crank….

[mpbarrett]

7 hours ago, egret said:

A new barrel and chain kit are on order.  I think I might try and get the chain cover (and tensioner) from the 1500 on the 1300.  It's got a graduated pointer on the front, so I should be able to measure static timing with my dumb timing light.  Fingers crossed I can get it sorted this weekend, but the garage has been re-purposed as a temporary store room while spitfire was out and about, so there's sorting to do.  That or I brave the elements. The weather gods look to be kindly at the moment, but with all the wind that can change very quickly!

I can lend you a decent timing light if you need it.

Mike (Histon)

[Escadrille Ecosse]

37 minutes ago, Nick Jones said:

https://www.chriswitor.com/proddetail.php?prod=145866HD
 

Not sure if 6 pot duplex fits 4pot small-crank….

It does. I have a duplex setup in mine along with the appropriate tensioner.

Mind you it wasn't the greatest so might be worth getting a replacement from Mr Wittor

[egret]

The new timing chain is on, but I'm now questioning the cam timing.  Careful measuring meant I put it back together previously as it came apart from when I got the engine, but I'm now questioning the accuracy.  So I'm printing out a degree wheel today and going to try and find the bits to make a sparkplug piston stop.  THis should allow me to do a slight modification to the ELOO method that @JohnD has written up nicely in the archives here.

My question for those that know is this:  If I measure the point where the rocker arms become unloaded for inlet and exhaust and bisect that to get the mid point, is this the equal lift on overlap point?  This would be significantly simpler for me to do, mainly becuase I don't have two dial gagues.

My current thoughts are that this is right, and sufficiently accurate.  It will also greatly simplify and speed up the job, and while it may be pushing towards the bodge end of the engineering spectrum (as opposed to the science end), it should be within the realms of the 1/4 tooth (2.17°) accuracy and therefore not a big limiting factor.

Any thoughts or considerations?  I'm under a bit of a strange time pressure on getting it back running.  I have plenty to think and plan, but very little to actually do any hands on work!

 

[Escadrille Ecosse]

If yours is any of the factory profiles or a symetrical aftermarket one ie inlet and exhaust have equal open close degrees, 22-62 62-22, 35-65 65-35, 40-80 80-40, etc then the method shown in the factory manual works fine.

If it's asymetric like most of the Kent ones then this won't work.

Helps if you have two sets of feeler gauges but I have in the past done it with one. Just a little more of a faff.

The relevant pages from the workshop manual

Edited April 15 by Escadrille Ecosse

[JohnD]

@egret,

Asowning two dial guages might seem like arrogance, and  anyway, mounting them both on the cylinder head is a probelm, so I later posted another method, that uses a spirit level! 

See: https://sideways-technologies.co.uk/forums/index.php?/topic/9639-a-new-method-of-cam-timing/#comment-134275

JOhn

Edited April 15 by JohnD

[Nick Jones]

3 hours ago, JohnD said:

As owning two dial guages might seem like arrogance

[Nick Jones]

I’ve got about 5 

[JohnD]

Yes, Nick, but you're a  proper engineer!     

There's a YouTube video from CEE Australia, where Kurtis buys a old lathe - and finds enough tools and instruments stored inside it to make his money back.  That included so many dial gauges that he was throwing away any that were not perfect!  

But I was making a half joke.   The greatest difficulty with using two gauges with the cylinder head in place is mounting them.    Theres too little space for the base magnets to grip on.    Bolting a plate to the head can help, but the spirit level idea avoids all that.  I have bought a 'precision' level since then, but not used it for this purpose yet.

John

[egret]

Thanks for the suggestions.  A spirit level did cross my mind, but couldn't work out a way to "zero" it given the car was on the wonk slightly.  I didn't realise taht such items existed relatively readily availably.

@Escadrille Ecosse lining it all up like figure 61 is the bit that started all my doubt here.  When I do this as best I can (engine in, bonnet on), it appears that it won't get close to this at all.  One tooth either way leaves the crankshaft some way away from the indicated TDC.

Maybe my engine and pulley arrangement are similar to this: http://mgf.ultimatemg.com/Triumph_Spitfire/Cam_timing/index.htm but that example seems a fairly extreme amount out.

Hopefully I'll have a piston stop made by this weekend so I at least have TDC known to a reasonable accuracy.  Then hopefully feeler gauges/ rocker rattle method will give me camshaft position accurately enough that I can get it started again.  At which point I might take up @mpbarrett offer of the timing light to set the meagjolt advance.  Then I think it just needs an oil change and some miles to make sure anything that's going to rattle loose does it before the rolling road!

[Escadrille Ecosse]

1 hour ago, egret said:

 

@Escadrille Ecosse lining it all up like figure 61 is the bit that started all my doubt here.  When I do this as best I can (engine in, bonnet on), it appears that it won't get close to this at all.  One tooth either way leaves the crankshaft some way away from the indicated TDC.

 

@egret asduming you are using the standard Spitfire single row chain then the camshaft gear is reversible so you can get within 1/2 a tooth.

If it is a long way out then I doubt that it is a measurement problem. More likely a problem with the bolt up of the cam gear.

But anyway. Regardless of what method you use you need to first set the engine to TDC with the timing chain OFF.

Then with the chain still off and the timing gear losely bolted to tje cam so you can turn it easily set the cam to rock with the feeler gauges as per the manual. 

Then remove the cam gear put the chain on and hold the cam gear against the to see if you can get the bolts to line up to within half a hole. If not then rotate it 90 degrees in the chain and try again. Still out try another 90 degrees.

If this doesn't get you close enough then remove the cam gear and turn it over, ie the face that was as the back is now at the front. Try to line up the bolt holes again. You should be within a half tooth of 'perfect'.

This is the way I have done it many times with feeler gauges before I had the dial gauges.

Personally I'm not keen on using piston stops through the plug, especially with the stop angled as it is on the Spitfire as it is very difficult to feel accurately when the piston contacts what with all the friction in there.

The best/approved way is with the head off and a dial gauge on the crown of the piston. But as neither situation applies to you using the key on the nose of the crank will close enough here. I have never seen one that isn't close to spot on.

[JohnD]

All,

An aside:   When I offered advice to egret, above, I tried to attract his attention by addressing him with "@egret", because when others do this the characters appear in the post in a blue cartouche, AND they get a 'notification', like that when someone quotes you.    But it didn't work!  How is this done, please?

John

[egret]

I just type @ and then start typing the username, then you click on the suggestion. That works for me @JohnD

[JohnD]

Testing

@egret

this is a test @egret (text first)

this is a test @egret.   (text first and a full stop)

this is a test   @egret

AH!    If I do the @egret, a window opens with your nom d'internet.  Click in that window - and the cartouche appears!    Thanks for the steer, @egret! 

John

PS Just seen Colin's advice to the above effect in another thread!  Thanks, Colin!  J.

Edited April 16 by JohnD

[Escadrille Ecosse]

1 hour ago, JohnD said:

Testing

@egret

this is a test @egret (text first)

this is a test @egret.   (text first and a full stop)

this is a test   @egret

AH!    If I do the @egret, a window opens with your nom d'internet.  Click in that window - and the cartouche appears!    Thanks for the steer, @egret! 

John

PS Just seen Colin's advice to the above effect in another thread!  Thanks, Colin!  J.

Reading 5 by 5 John 

[JohnD]

I'll have you know, Colin, that I've got way beyond the Jack and Jill go to School book!