Pimp My Ride

[Adrianb]

I’ve been given a JC Midge that has a Herald 1200 high compression engine. The vehicle will never get to go on the Road Legally Due to DVLA IVA rules so I thought I would Pimp the engine, if it was you what mods would you do to a basic 1200? Obviously I would need to do something to help stop the car as well so thoughts on upgrades many thanks Adrian B. 

[PeteStupps]

How much money and time do you want to spend??

Ideally you'd get hold of an 8-port SAH cylinder head, but they're not exactly easy to find.

Failing that, get someone who knows their stuff to work on the existing 1200 head. Bigger inlet valves perhaps? Skim to increase static compression, get a camshaft with more overlap and lift. Maybe have the block line bored for cam bearings (I'm not sure if the Herald 1200 block ever got the larger cam journals). Have the crankshaft and all rotating bits dynamically balanced. Change to a diaphragm pressure plate for the clutch, not forgetting to change the release bearing carrier.

Depending how much overlap your new cam has, perhaps fit a Weber carb or convert to EFI. Get a tubular exhaust manifold and larger bore system.

For stopping, upgrade to later Spitfire uprights for type 14 calipers, or better, vitesse/GT6 type 16. You can get spaced calipers which will fit a vented disc, if it's going to be for trackdays. 

[Tim Bancroft]

Some great info here:

http://auskellian.com/paul/links_files/performance_enhancements.htm

[Adrianb]

Thanks Pete and Tim. That’s a great help. The plan is to make it Fast and Safe for the Track, but it will be coming second fiddle to the 13/60 convertible project but I intend to get it sorted sooner rather than Later before Domestic management realise what’s going on!

[Clive]

Oh crikey, to be fast on track will be difficult unless you have deep pockets. 

Better bet is to get a 1300 small journal engine, and tune that. But if you really want to use the 1147, get the head skimmed to give a compression something around 10 and some porting etc, a good cam (newman seem to be top dogs at the moment) and slap a weber/dellorto on it. An extractor manifold will be required too. Be careful with exhaust, noise limits are sometimes quite low. You may get somewher near 100bhp with a good rolling road setup including distrbutor, though in reality on track the advance curve is not important as revs should alsways be over 3k, often double that.

In terms of safety no1 is good brakes. Changing to later Vitesse sized calipers and discs should be quite straightforward, along with something like mintex 1144/55 or Ferodo DS2500 pads. Suspension may benefit from tweaks too. Stronger/lower front springs, and a swing spring at the rear with matching ARB. Set the steering geometry up nicely, and that lot will be about as good as you can get for sensible expenditure. However, do go and take part is at least one trackday before committing, having a dedicated track car is quite an extravagance.  Maybe even pop along to a trackday and blag a ride or two. I am at the castle combe day in May with a few others, pop down, bring a helmet and see what it is all about. Or your local meeting, there is one not far from you😉

[Adrianb]

Thankyou Clive. All noted and much appreciated. I need to do my homework on the track days as I might have an eyesight issue that would affect sharing a track, But I have driven a track near Loughborough that allows for these issues.

[PeteStupps]

2 hours ago, Adrianb said:

near Loughborough

Was that Mallory Park? MGOT did a trackday there last summer, with me and two other Triumphs keeping our end up. Good day out

[JohnD]

Pete, Suggest you read: https://www.teglerizer.com/triumphstuff/performancedata/III_whichengine.htm

Complete Spitfire engine building tutorial - works for sixes as well, which would suit your Midge even better.

John