GT6/ TR6 Engine Swap in a Triumph Spitfire

[Paul B]

Advice required, i'm after advice from people who have put the 6 cylinder engine in a Spitfire, think i have all the mods that need to be done, turrets, springs dampers, GT6 Brakes (Already fitted) which engine / gearbox did you use, diff prop. Does the gt6 radiator mount fit onto the spitfire chassis.

I have a good GT6 Bonnet so .............. 

 

Thanks in advance

 

[Nick Jones]

Paul,

Apologies if you’ve already been through this thought process, but be aware that sticking 200kg in the front of a Spitfire changes it nature completely. It’s not just a Spit with more grunt. There’s a considerable loss of nimbleness. Also, more grunt…. Actually a well sorted 1500 will be quicker than a standard GT6 in the twisty bits and possibly in a straight line too. And a 4 pot costs about 40% less to do serious engine work to.  And this is coming from the owner of two 6 pot cars! Ok, so the 6 sounds so much better……

If you already past the above. Then the chassis is basically the same. I built my GT6 on a 1500 chassis. Up front you would need to add the rad mounts if running a GT6 radiator, though maybe not as it’s possible even preferable to use a light, cheap Golf mk2 GTI, which involves making your own mounting arrangements. I did add the mounts, I also used the Golf radiator - can’t remember if the two got joined.

Gearbox… meh, ideally a beefed-up three rail GT6/Dolly 1850 hybrid with J-type. Otherwise a Ford T9 conversion but make sure you get a 2.8 V8 T9 box.

Spit 1500 3.63 diff is fine (best simple option anyway). Rear brakes also.

Still think a well tweaked 1500 on EFI has many benefits..,,

[Bradman]

Fully agree with Nick 👍🏼 I have a Gitfire, so it has all the right mechanicals, but due to a PO botching an engine rebuild it’s temporarily running an MG Midget 1500 engine / box + Spit 1500 prop until I’ve finished rebuilding a 2L engine 🙄 To offset some of the extra mass of the 6 in a Spitfire shaped car I’ve used lightweight components where possible, such as fibreglass bonnet, an alloy water pump housing, and light alloy engine plate front and back.  It won’t be enough to cure the handling…. Some people choose to move the engine back an inch or 2, by using new engine mount positions and a shorter propshaft.  I’m told this works well, especially with lightweight stuff like I’m using, and you don’t need the GT6 bonnet this way, a little sleeper 😇 For the engine, there are some changes to be aware of: use a GT6 sump to clear the steering rack, and use GT6 inlet manifold to ensure the carbs miss the bonnet.  A GT6 bonnet is needed to give clearance to the thermostat housing, unless moving the engine backwards. The transmission tunnel has a different shape due to the starter motor being on the opposite side to a 1500, speaking of which I think a Spitfire shell needs a tweak here for the same reason.  A fun car if you do go ahead: it’ll pull a little quicker than a standard GT6, but will be trickier on the corners than either a GT6 or Spitfire.

[Clive]

But if you want teh 6 cylinder noise, and to build a pretty std spit 6...

1. Inlet manifold. Needs to be a proper GT6/Vitesse type, all others WILL mean cutting holes in the bonnet. Other option is PI or EFI, but if that is your intention, ask. Nick is your man for EFI

2. Engine. The 2litre v 2.5 debate is unending. The 2 engines are very different in character. The 2 litre is revvier, the 2.5 is more torquey and pulls better at lower RPM. And it is not a subtle difference. You really need to drive both, and then sit down and have an honest debate with yourself about what you really want. Be aware the 2.5 is going to stress the gearbox and diff more, and solving that issue is not simple.

3. Gearbox. The simple option is the std GT6/Vit box, with overdrive. Better is to use the internals from a later dolly 1850 or the whole single rail box. It has a bigger mainshaft tip, and comes with the stronger j type OD as std. That requires a little fettling, particularly to the GT6 bellhousing for the selector rod. And a bespoke 1" shorter than std prop.

4. 3.63 diff a good choice. 3.27 better for a 2.5, but it is weak and liable to fail (from experience, others have fitted LSDs to help)