Andrew's Mk IV Spitfire

[egret]

Thanks to @mpbarrett I now have some mx5 "tombstone" seats in my car, and they feel like a pretty big upgrade to me. The height issue that's often spoken about is not one for me for two reasons, firstly I'm no giant at 5'7", and secondly the rails of seats I took out were mounted on 1" steel box section for some unknown reason. So I'm actually slightly lower than before, without even mentioning the word foamectomy!

Next job is inertia reels I think. I think securon 15/500 are the ones, but can anyone confirm? I'm also fairly sure I'll need to do some work to form the lower mounting points on the wheel arches.

 

Still looking for a roll hoop if anyone has one languishing unloved somewhere...

[mpbarrett]

they look good! Glad they found a home.

Mike

[egret]

Its running better again after messing with a few more things and no's 1&2 plugs fouling. Turns out the carb floats were at different heights meaning fueling had gone wonky. I've mix and matched the best pair from the 4 I have to give a closer level.  This might have to be another part to replace. These carbs are likely to be all but new by the time they work right.

[egret]

Well I now have inertia reel seatbelts. The old fixed belts look the age of the car and it's probably best I'm not relying on them anymore.

FIA spec backing plates have been used to add additional fixings on the lower arches, drilling holes was less traumatic than expected!

Given how exposed they are too the elements in the wheel wells, what's the general consensus here. I'm considering using some silicone mastic for stuff and essentially bond them to the outside of the body, mainly to keep grot out of the gap, but also to stop them falling off if I ever remove the belt. I can't see any downsides other than cleaning it off if I ever decide to weld the plates in.

[egret]

Also, got one of my kids to video part of today's adventure. The hard top was on so it's quite noisy. You can't really make it out here, but there sound of the engine only really comes on song about 4.5k.  I'm hoping I can improve this with some improvements to fueling and timing but it might just be down to the physical components of the engine.

Happy to have thoughts and suggestions from one and all.

 

[Nick Jones]

Sounds ok to me…. 

[Escadrille Ecosse]

And I like the wee bit of commentary too  

Personally I wouldn't use silicone sealer anywhere you might want to paint again. I've always used a good dose of waxoyl behind washers. Holds them in place a bit and keeps the rot out.

[egret]

I have a wonderfully chatty co-driver and videographer.  They have also stated that they could, maybe, look after the car when I get older.  A decade away from holding a licence and already trying to steal my car

[Nick Jones]

The next generation of custodians need to be encouraged…. 

[Escadrille Ecosse]

1 hour ago, Nick Jones said:

The next generation of custodians need to be encouraged…. 

Very definitely. Keep up the good work 

[egret]

A roll cage has been acquired. It has safety devices stickers on and mandrel bent bends, so is a good start.  It design is as diagram 1 in appendix 2 of the motorsport UK Blue book Section K - a main hoop with two supporting arms, but no triangulation.

The main hoop base plates had been welded on with pigeon poo, so I've started grinding that back and I think I'll actually cut them off so I can check tube wall thickness against the Motorsport UK info requirements.  The rest of the welding looks good, but given I have no functional welding skill I'll be looking to find a place to get the feet welded up. 

Mocking it up the cabin it does reduce seat movement options a little, but I (all 5'7" of me) still fit comfortable so I'm going to call it good.  Apologies in advance if I meet any of you and you fancy a go - it might be cramped!  Soft top and hard top both appear to fit too which I believe is as per the design.

It rests on the flat area above the trailing arm attachment points and bolts into the wheel arches at this point, as well as having separate arms which rake back to connect higher up on the wheel arches.  I'm going to make some steel plates for the inside of the arches so the thinner arches are sandwiched between the thicker plates as per 13(b) in the same document.  I'll base these on the 3mm thickness and 120cm2 area requirements, and might be able to use the relatively cheap seatbelt backing plates that are available.

I'm aware that roll cages are a sensitive subject, but this one looks good to me.  Far enough away from me that I'm confident I can fix it well enough that it won't enter my space in a rear end shunt, and strong enough that it will give me a fighting chance under a reasonably wide range of nasty scenarios.

Edited August 12 by egret

[egret]

The below is karma for bragging to @PeteStupps that the engine didn't have issues with blowing oil out the seals, and that it seemed to love high revs...

Last night I was about to set off to the local triumph meet, with an excited young passenger. Teacher training days meant a late night was allowed, and this was too be guilt exploited by the little one.
Sadly the addition of said passenger had us running late, and answering the barrage of questions had me slightly distracted, so when I started the car I didn't immediately notice the oil light staying on, and it wasn't into the unusual noise filtered though to my brain that I turned it off, a few seconds later. A mild panic and check showed that my 'flawless' journey to brands and back may have consumed quite a lot of oil as the dipstick was now well below the lower line.
Topping up the oil left me with what appeared to be a glittery dipstick under the limited visible provided by the streetlights. A quick look in my catch can shows no oil in there, and the coolant looks ok too, so I can only assume it's worn rings (one of the few parts I didn't replace during the rebuild) and the oil went out the exhaust. It didn't appear to be smokey, but maybe that's hard to see at motorway speeds? Given there are no large puddles underneath the car, I can't think of anywhere else it could have gone.

The lesson learned is to be more fastidious on checking oil level.  I had the chance to check after the run back from Brands, and before starting last night, but didn't.  I have my excuses, but they are meaningless against the reality of starting an engine without enough oil in it!

My plan is to drain the oil and look at the state of it.  Unless it comes out immaculate I'll drop the sump and check the state of the main and big end bearings and replace if necessary. I'll have a look at the bores from underneath and see if there's any noticeable red flags on scoring.  Then, depending on the severity of what I find, I might have to check the camshaft bearings too.

So far my assumption has been that replacing piston rings will need the bores deglazing and this means engine out to properly clean up after. Is it inviting disaster to try and deglaze the bores with the engine, camshaft, and crank in place? I'm hoping that it produces only minor amounts of cast iron dust and that bearing surfaces could be protected, so a good clean of the inside of the crank case might suffice, but I'm not sure if that's optimism clouding my judgement.

I'm loathed to pull the engine out again, but realistic that it might be on the cards, so I'll hope that I can get away without touching the rings for now and keep meticulous records of miles and oil consumption.

Then maybe do the rings over winter.

[RedRooster]

4 hours ago, egret said:

The below is karma for bragging to @PeteStupps

Sadly the addition of said passenger had us running late, 

Guess she was attractive? 

Whats your oil pressure like now? 

[PeteStupps]

6 hours ago, egret said:

the unusual noise filtered though to my brain

Uh oh! Was the unusual noise knocking? How many miles since last top-up? 

If you heard it knocking I'd be inclined to drop the sump and check the big end bearings. Rampant oil consumption isn't particularly alarming though. If it's not pouring out of a hole somewhere then pound to a penny it's rings / bores. Wynns magic goop does slow consumption down if you want to delay the inevitable rebuild...

6 hours ago, egret said:

Is it inviting disaster to try and deglaze the bores with the engine, camshaft, and crank in place?

I seriously considered doing this for a while, and also whether just changing oil control rings was worth doing - my bores had a pronounced lip at the top so would likely crack new rings without a rebore. Yours may be similar...? 

I'm sure it's feasible to hone bores without removing the engine; you can wrap the crank and oil pump carefully and flush it all 15 times afterwards. You'll have to decide for yourself whether it's worth it though; once you've got the head off you're halfway to removing the engine anyway. 

Definitely monitor mileage against oil use for a bit though, think I was doing about a pint every 250 miles.

P.S. I'd forgotten your bragging until reminded! But the fates don't forget so easily

[Escadrille Ecosse]

As Pete says, you can hone the bores in place, and protect stuff while you do that. The hard part is protecting the rest of the engine while you clean the bores as this needs doing thoroughly. The cast iron you've removed is not the biggest worry, it's the carbide grit from the honing tool.

Suggest taking the engine out is probably quicker anyway. And you save yourself the anxiety issues.

If you have all the spares (yeah, I know) then doing the whole thing in a couple of long days is possible.

Or if the oil pressure is OK run it for a bit until you have more time.

[egret]

I'm pretty sure it was more of a scraping noise than knocking, I also think it achieved reasonable oil pressure but I'm attempting to learn from my mistakes and be very cautious, so I've not attempted to start it again until I've at least changed the oil.  I've got some garden construction work in the diary this weekend so it's unlikely to be resolved for a weeks or so, I'll update when I know.

It's done about 800-900 miles since the rebuild, and I did a quick oil change after the first 50 miles where I over filled it a little.  So it's gone from over top to under bottom in 700 miles.  I think this is about 2 quarts total, or about 1 litre every 300 miles.  Some has been left on the drive, and some has become natural  rust prevention, but it doesn't leak badly enough that I'm noticing any puddles.  I'm using the semi-synthetic millers classic sport 20W50 if that makes a difference.

[Escadrille Ecosse]

39 minutes ago, egret said:

It's done about 800-900 miles since the rebuild, and I did a quick oil change after the first 50 miles...

I'm using the semi-synthetic millers classic sport 20W50 if that makes a difference.

Did the rebuilt block have new pistons and/rings? And if so how was it run in?

Reason is if you do the bores/rings then they need run in for about 200- 300 miles on a fairly basic oil. Running in oil is best but monograde will do or you risk glazing the bores. Don't use synthetic or semi-synthetic until the bores are properly run in. It is too 'lubricating'. 

[egret]

Good idea Colin, but this is one of the few times where it wasn't a lapse in my judgement causing an issue.  No comment can be made on the custodian who oversaw the bedding in of the existing rings.

No, the rings and camshaft bearings were not replaced during my Christmas re-build/refresh.  They looked acceptable to me and a couple of second opinions, so I took a punt and left them alone.  They passed the fingernail test despite not looking amazing (photos below).

Having never built an engine before, it felt like pistons out, honing and replacing the ring s could be the final straw in an already borderline overwhelming project.

If the oil change goes ok then I'll do a hot compression test as described by Hamish recently to get an idea of how the rings are performing.

I was, and still am, aware that they will need replacing in the next few years.  However as it was a complete unknown engine to me it felt justifiable to check it wasn't a lemon before I invested too much into it.  Other than this oil consumption and a slightly disappointing dyno headline figure, I can't really fault the engine!

So I'm aware that there's another engine out session in the next few years.  The plan was (is?) to save enough for an aggressive camshaft and some lightening+balancing of internal components.  Then build the engine with all the bells and whistles when the engine came out again.  Life is doing it's think of starving this particular project of funds, so hopefully I can just go on burning a little extra oil for another year so I can save up enough to build an engine that will be strong and last for many thousands of miles.

Edited September 5 by egret

[PeteStupps]

19 hours ago, egret said:

So it's gone from over top to under bottom in 700 miles.  I think this is about 2 quarts total, or about 1 litre every 300 miles

Two pints from max to min lines on the dipstick, not two quarts! So you burnt maybe 3 pints in 700 miles? From my experience of cars this age, that's not massively surprising for an engine on its original rings & bores. Not ideal but not in acute need of rebuilding. Just have a bottle of oil in the boot and keep an eye on the level.

Wynn's 'stop smoke' will slow down oil consumption, if you get bored of topping up.

[Nick Jones]

On 9/6/2024 at 9:37 AM, PeteStupps said:

Wynn's 'stop smoke' will slow down oil consumption, if you get bored of topping up.

This…. On the 2009 10CR the Vitesse used 6 litres of oil in 3,200 miles. 
 

On the 2011 10CR, with no mechanical work done we managed 2200 miles on 2 litres. The difference was a can of Wynns Supercharge or maybe the STP equivalent - both work. It also managed the 2013 run…. Used zero oil on the 2015 run with the new engine….,

[mpbarrett]

just back from the 10CR (down to the south of France turn East and then north in Italy and then thru to Switzerland and then into Germany) the Herald used max to min on the first 3 days, with a rather nasty smell of burning oil and then it stopped using oil very strange. lots of long days driving and far too much motorway driving. More in the Little red thread.

mike (very tired after 5 days driving...)

[Hamish]

Do glazed bores get better with prolonged driving like above. And thus reduce oil use.

[egret]

So keep an eye on oil levels and drive it like I stole it. Got it

[Escadrille Ecosse]

11 hours ago, Hamish said:

Do glazed bores get better with prolonged driving like above. And thus reduce oil use.

No, unfortunately.

11 hours ago, egret said:

So keep an eye on oil levels and drive it like I stole it. Got it

Absolutely 

[egret]

Changed the oil, still have good oil pressure and no new noises.  Did a few calculations and got 36.1 mpg on the run to brands hatch and back. Top down, and motorway speeds.  I've not calculated the calorific contribution of the burned oil though...