1970 GT6 MK2

[Speedysix]

On 6/1/2024 at 2:13 PM, Nick Jones said:

I had to make a couple of those anchor studs as I also could not find any to buy. Had enough trouble finding one to copy.

My spare is a mk3 (or MkIV Spit 4.5J steel with a 155/80 13 on it. That has the same rolling radius as the 175/70, which I think would be a very tight fit at best. I’ve mounted the spare face-down so I can put “stuff” inside it. I think factory is the other way up, though my particular car had no clues either way as found!

The spare won’t match my 5J fronts or 5.5J rears but at least the diameter is correct.

I did manage to find a company that sell them, and the clips that they go into. A company called brisco, and list it as a gt6 part too. 

a bit pricey, I may be tempted as it's just the one corner of the right hoard sitting up at the moment. If I do buy the pack of 6, shout me if you're in need of any or anyone else for that matter. 

As for the spare, I pulled off one of my d1's which run 175 70 13 and it does fit in the boot. Good amount of space above and around it. I'll have to rethink how I organise my spares as they're definitely not all going to fit anymore!

Just need to track down a steel wheel to put in the boot, or an ally. Am I right in assuming a mk4 spitfire one is the same as the mk3 gt6 and will fit my standard hubs? I know the early spit ones don't clear the caliper. 

[Speedysix]

On 6/2/2024 at 3:10 PM, PeteStupps said:

How odd, I've swapped my Spitfire door handles around several times and don't find it too bad - only mildly irritating!

That boot board looks great, very professional. 

Thanks Pete! Well worth the time I think

I mean um probably exaggerating,  it's just very fidly, especially with relatively new springs behind those plastic discs. Glad it's done now!

[Speedysix]

A few more little odd jobs in the evenings, wipers have been the next target.

The nos trico ones thst I bought are a terrible fit on the current arms. Turns out they're 2 diffrent sizes!

 

I have tried them on the car and they just slop around on the arms, so go back to the crappy new wiper blades or find some 7mm arms, i assume they're 7mm. I assume all these blades are the same more or less across the bl cars of this era?

Currently about to remove all the old seatbelts in the car as they are the original static 3 point britax lap ones. They're just quite tired so I'll be upgrading to a set of these

somthing a little more moden and safer. These are as close to the originals as I can possibly find. I would rather inertia over static not that it would make a difference in a crash!

I can now also confirm that the block has been painted, water jacket has had white vinegar sitting in it for about 4 weeks now and neauturalised. Plenty of water to flush out any debris too, I even used a inspection camera and fed it into the water jacket to check for any large chunks thst may break off. I'm aiming to clean the block out tonight with my collection of brake cleaner and gun brushes. You'll also all be happy to know that I have a compressor finally! So I can avoid the mistake from engine no1. 

And before you say it, I've already got put the thrust washers the right way around going endlessly around in my head.

[Escadrille Ecosse]

Wiper arms. Early cars used the 5.2mm width. Later cars 7.2mm. Not sure of the switch date but for Spitfires it was MkIV on I believe from experience.

Seatbelts. Those look very good. The Vintage Warehouse 65 is new to me will need to have a look.

Properly adjusted static belts are safer than inertia reel type. But the 'properly adjusted' part is key there.

[RedRooster]

1 hour ago, Escadrille Ecosse said:

Properly adjusted static belts are safer than inertia reel type. But the 'properly adjusted' part is key there.

Toite, toite like a tiger. 

[RedRooster]

Saying that I'm away to Holland on a job tomorrow, 

[PaulAA]

43 minutes ago, RedRooster said:

Saying that I'm away to Holland on a job tomorrow, 

 

[Nick Jones]

4 hours ago, Speedysix said:

Am I right in assuming a mk4 spitfire one is the same as the mk3 gt6 and will fit my standard hubs?

Yes, same wheel. I have a pile of them here. Come and choose one (or several) next time you are passing. They are not pristine (!) but free to you!

4 hours ago, Speedysix said:

too, I even used a inspection camera and fed it into the water jacket to check for any large chunks thst may break off. I'm aiming to clean the block out tonight with my collection of brake cleaner and gun brushes

Check especially the rear right corner near where the block drain is. Tends to be where the thickest deposits are, though to be fair the saloon blocks (which that isn’t) are worse for that due the the angle they are mounted at. If the block drain hole is completely clear, it’s probably fairly clean.

On the wiper front, I think yours  would have been 5.2mm originally. Doesn’t really matter which so long as everything matches and is the right length. I posted links to the Tex site before but as per that thread I don’t necessarily agree with their listing for the mk3 at least.

[Speedysix]

On 6/5/2024 at 3:37 PM, Escadrille Ecosse said:

Wiper arms. Early cars used the 5.2mm width. Later cars 7.2mm. Not sure of the switch date but for Spitfires it was MkIV on I believe from experience.

Seatbelts. Those look very good. The Vintage Warehouse 65 is new to me will need to have a look.

Properly adjusted static belts are safer than inertia reel type. But the 'properly adjusted' part is key there.

Ah I see! Are the later spit ones the same aside from the difference in thickness? I'd rather keep these blades as just from trying them on the windscreen and squirming water everywhere, they work significantly better than the modern equivalent. 

I would rather keep my current original static belts, I do like that tight feeling and I don't really drive leisurely mine are just very tired. There are people selling nos ones for silly money on ebay. I'm leaning now towards refurbing these or hunting down a good second hand set.

 

[Speedysix]

On 6/5/2024 at 7:41 PM, Nick Jones said:

Yes, same wheel. I have a pile of them here. Come and choose one (or several) next time you are passing. They are not pristine (!) but free to you!

Check especially the rear right corner near where the block drain is. Tends to be where the thickest deposits are, though to be fair the saloon blocks (which that isn’t) are worse for that due the the angle they are mounted at. If the block drain hole is completely clear, it’s probably fairly clean.

On the wiper front, I think yours  would have been 5.2mm originally. Doesn’t really matter which so long as everything matches and is the right length. I posted links to the Tex site before but as per that thread I don’t necessarily agree with their listing for the mk3 at least.

That's very good thank you Nick, I'm sure it'll suffice for an emergency

I did have a very good route around this area. Between cylinders 1 and 2 theres some shoddy cast work, but otherwise all clean and clear.

I will try and get a hold of the later wider arms. These 7.2mm blades are the correct length and fit very nicely to the screen, and they curve properly to the contour or the screen compared to my modern equivalent.

I bought a brand new of tex ones once from moss and they wouldn't even fit on my wiper arms

[Speedysix]

Today I've been doing a bit of chemistry.

I've been modifying my custom sunvisors that I made as they sit too far down using the mk3 sunvisor brackets. So, after measuring, I essentially did this:

Simply Cut, welded and re drilled the hole. The head didn't exactly come out how I wanted but it's good enough. These are the only mounting point which is another issue as they're only held on with one self tapper. They did work and only occasionally flop down, I think a dab of threadlock might help with this.

Anyway, this one only need a bit of finishing off and then it needs some treatment. The existing ones went quite rusty after a couple of years so I opted to try some diy chrome plating

White vinegar and a pure nickel plate anode. Cost about 15 quid. This is the nickel electrolyte after about an hour and a half on a 3 amp car charger. The plan is to attempt to plate the brackets to give them a decent degree of shine.

I also managed to cc the head. Regardless of whatever cam, I would finally like to increase the C.R and do some amateur porting work. I have no idea what to increase the C.R to, seen various figures, I did have a yellow bible once upon a time that might have had more info in it. Any recommendations without running the risk of breaking into an oil way or waterway.

Am I also right in saying that the chambers hardly need touching? It's all in the ports? Tonight's reading will be on a few of the head threads on here and trying to find an online vizzard book.

 

Whilst I'm on the head subject, I'm stuck on valve springs. Originally I've been running the county red springs. I've come across quite a few threads on here that say avoid anything yellow and toilet tune. Then numerous issues with springs going soft after a while. Assuming we are running a hotter cam, what's the general consensus? Someone who crops up a lot in a lot of the older threads called Gareth or GT, seems to reccomend jaguar springs but only genuine nos... I'm not sure if I'm giving this more though than needed but some advice in the right direction would be appreciated

Anyway, head came in with an average cc across 4 chambers of 35.25cc, seems right? Plus or minus a cc or so. I do have a burette from doing numerous mini heads so I was well equipped for the job

 

[Nick Jones]

I should make some sunvisors…. Though mostly I’m sat so near the roof I don’t often really need them.

CR….. is really cam dependent. If sticking with 308778 you do not want more than factory, especially if sticking with clockwork distributor and carbs. You might get away with a little more with the TR5 cam but not personal experience. Don’t overdo it. You’ll loose more by having to back the timing off to stop it pinking its head off than you gain by upping it.

Springs https://www.chriswitor.com/proddetail.php?prod=CW2906

Doubles give you two chances of not dropping a valve.

[Speedysix]

24 minutes ago, Nick Jones said:

I should make some sunvisors…. Though mostly I’m sat so near the roof I don’t often really need them.

CR….. is really cam dependent. If sticking with 308778 you do not want more than factory, especially if sticking with clockwork distributor and carbs. You might get away with a little more with the TR5 cam but not personal experience. Don’t overdo it. You’ll loose more by having to back the timing off to stop it pinking its head off than you gain by upping it.

Springs https://www.chriswitor.com/proddetail.php?prod=CW2906

Doubles give you two chances of not dropping a valve.

I usually just go for sunglasses, since I've built the car they've been more aesthetic than practical.

I'm going to cc the head again as I really need a piece of perspex over the chamber to get a good reading, 35.25 seems quite low to me. If I don't get those seatbelts and manage to scrounge some better quality standard ones I'll get the tr5 cam. The only thing stopping me was having someone localish with a rolling road and knowledge of carbs to change the needles to suit and I have now found one!

Is the 9-9.5:1 region overdoing it if I have the tr5? I assume anything over 10 is too much?

If they're good enough for Chris to sell them I'll be going for them, thanks Nick

[Nick Jones]

Yes, you need a cover to get an accurate reading.

Both Mk2 Vit/GT6 and TR5 are 9.5:1 from the factory. The 2L has better squish, but the 2.5 has better (more even) mixture distribution. Both can have pinking issues as standard as designed for 5star fuel.

I would not increase it from that unless planning injection and/or mapped ignition.  It does make that much difference. When I first injected the Vitesse the engine was factory standard. Running on carbs it pinked and ran on, even with the timing retarded from the factory figures. The injection completely cured it. Notably, for the first year or so, I retained the standard distributor, with points, with the ECU trigger signal coming from the points. I was even able to advance the ignition back to book figures and slightly beyond without pinking. Mixture distribution matters.

[JohnD]

May I respectfully suggest my article on all things to do with CR?   See: How To Raise The Compression Ratio, Safely And Effectively. - Technical Articles & Reviews - Sideways Technologies (sideways-technologies.co.uk)

Good luck!

John

[egret]

John's thread is a good read.  I recently did my standard mk3 spitfire engine to 9.5:1 and even under very lean conditions caused by fuelling problems it didn't knock, even with glowing tubular headers!  However this is very anecdotal, and maybe megajolt and 0 ethanol high octane fuel helps this.

The conclusion I came to was that 9.5 is a good compromise.  If I put in a bigger cam then I'll consider increasing it.

[Speedysix]

17 hours ago, Nick Jones said:

Yes, you need a cover to get an accurate reading.

Both Mk2 Vit/GT6 and TR5 are 9.5:1 from the factory. The 2L has better squish, but the 2.5 has better (more even) mixture distribution. Both can have pinking issues as standard as designed for 5star fuel.

I would not increase it from that unless planning injection and/or mapped ignition.  It does make that much difference. When I first injected the Vitesse the engine was factory standard. Running on carbs it pinked and ran on, even with the timing retarded from the factory figures. The injection completely cured it. Notably, for the first year or so, I retained the standard distributor, with points, with the ECU trigger signal coming from the points. I was even able to advance the ignition back to book figures and slightly beyond without pinking. Mixture distribution matters.

Understood, thanks Nick. I have a funny feeling the existing head has been skimmed at one point in its life, I will repeat the cr measurements and then asses.

I'll be sticking to my hs6's, the bank is slowly emptying from all this engine work

[Speedysix]

5 hours ago, JohnD said:

May I respectfully suggest my article on all things to do with CR?   See: How To Raise The Compression Ratio, Safely And Effectively. - Technical Articles & Reviews - Sideways Technologies (sideways-technologies.co.uk)

Good luck!

John

Thanks John, I'll be taking a good look at this tonight!

[Speedysix]

4 hours ago, egret said:

John's thread is a good read.  I recently did my standard mk3 spitfire engine to 9.5:1 and even under very lean conditions caused by fuelling problems it didn't knock, even with glowing tubular headers!  However this is very anecdotal, and maybe megajolt and 0 ethanol high octane fuel helps this.

The conclusion I came to was that 9.5 is a good compromise.  If I put in a bigger cam then I'll consider increasing it.

I think this seems to be the general figure, I don't know many who have gone close to 10

[Speedysix]

Just a quick update and ask for advice, block has been cleaned inside and out as has the crank.

I've begun the final build!

I've included a picture for sanity sake of each thrust washer! You will note the steel side on both facing the bearing thus the bronze side with the grooves against the crank!

End float with the dti is in at 0.23mm, factory manual says 0.15 and 0.20. Will I get away with this? The oversize thrusts at 0.005 and 0.010" available put it out of spec?

[Nick Jones]

That’s irritating. Measured dry/light oil or with assembly lube. If the latter I suggest repeating with engine oil only on the thrust washer surfaces.

At where you are now, I’m inclined to say to stick with the bigger number as 4 thou is a bit snug. Oil gap needed!

Check again after a couple of hundred miles.

[thebrookster]

Your other option is to use the 0.005" oversize, and remove some material with a glass pane and some fine wet'n'dry?

[Escadrille Ecosse]

Go with Nicks suggestion regards oil rather than assembly lube.

If still a little tight adjust as suggested by Phil. this was recommended to me by John Kipping. It doesn't take much to achieve the right thickness.

[Speedysix]

On 6/7/2024 at 8:05 PM, Nick Jones said:

That’s irritating. Measured dry/light oil or with assembly lube. If the latter I suggest repeating with engine oil only on the thrust washer surfaces.

At where you are now, I’m inclined to say to stick with the bigger number as 4 thou is a bit snug. Oil gap needed!

Check again after a couple of hundred miles.

Typical with my luck I will, I went a bit too liberal with the graphogen so hopefully cleaning may create a larger tolerance thus enabling me to squeeze a 5 thou oversize one in

[Speedysix]

On 6/7/2024 at 9:23 PM, thebrookster said:

Your other option is to use the 0.005" oversize, and remove some material with a glass pane and some fine wet'n'dry?

 

On 6/7/2024 at 10:06 PM, Escadrille Ecosse said:

Go with Nicks suggestion regards oil rather than assembly lube.

If still a little tight adjust as suggested by Phil. this was recommended to me by John Kipping. It doesn't take much to achieve the right thickness.

And just to dummy check here, remove some from thr steel face, not the bronze? I will order some anyway and trial fit, I'd be happier with it closer to the 0.15mm min tolerance than over