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1976 Triumph Spitfire Build thread


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10.2:1 will be fine with most hotter cams if you run on premium gasoline, as they lower the effective dynamic compression whilst the engine runs. Like you I'm a bit wary though as Paul's chart doesn't seem to match his Excel calculator.

Just measured my skimmed head and it measures marginally thicker than the Toledo head at 75.57mm, which should give it 10.35:1 (according to the calculator, at least). That's with a TR5 profile cam shaft which is not that aggressive, although the car is running sequential EFI with mappable ignition which may help. Runs great and never had any knock issues on any type of petrol, although it doesn't run as well on 95 octane.

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Apologies....  I have made a double error above.  My "big valve" head on a 1500 is a 218141.  From a 1300 Toledo.  It gives a CR of 9.6:1, both calculated and physically measured using a burette/glass-with-hole method.

With a Mk3 Spitfire profile camshaft (Canley Classics) it gives very good mid range power and plenty of torque up to 4000rpm and was looking very promising. However, I never got to try it any higher as my engine had some issues in the latter stages of running it in, and I had to pull the engine out to investigate.

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59 minutes ago, hardhatharry said:

I was thinking a mating it with a TH5 kent cam

I had a Kent TH5 cam in my 1500 with 10:1. Needed 99octane. Sadly the cam lost one lobe almost completely and another was going. Not sure if things have improved, but I would be looking at Newman cams and their "super" followers

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My 1300 has a 300 duration cam, 10.75 CR, twin 40 Webers and mechanical distributor and although I try to run it on Shell V-Power which is 99 RON (and has a very nice smell too) it will run quite happily on BP Ultimate which is 98 or more likely 97 depending on who you listen to.

I have even used 95 RON when there was no other option (long journey to and from an event on a 3 gallon tank). Just needed to be a little less heavy footed.

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4 hours ago, sparky_spit said:

Apologies....  I have made a double error above.  My "big valve" head on a 1500 is a 218141.  From a 1300 Toledo.  It gives a CR of 9.6:1, both calculated and physically measured using a burette/glass-with-hole method.

With a Mk3 Spitfire profile camshaft (Canley Classics) it gives very good mid range power and plenty of torque up to 4000rpm and was looking very promising. However, I never got to try it any higher as my engine had some issues in the latter stages of running it in, and I had to pull the engine out to investigate.

Hm, I'm amazed you can get away CR-wise with the MKiV big valve head on the 1500 block, with standard pistons.

If I recall well, GT recommends in his tuning book to use the late US dished pistons to compensate for the small chamber- if you mate the big valve MKVl head with the 1500 engine.

Also, you  could slightly break/round the corner on the squish edge and the the ridges  l&r of the spark plug to make it more resistant against detonation.

Cheers,

Patrick

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  • 3 weeks later...

Had a bit of a break over Xmas and the cold snap, I had every intention of doing a bit but the temperature change stepping out of the front door force me to skittle straight back in the house. Back on it now.....

Cleared all the tools, parts and rubbish out of the boot, taken it back to metal and into primer.IMG_20210104_212134.thumb.jpg.4c27e45caabb0fdf548e98ff6614288e.jpg

Makes a hell of a difference.

Taking the deck back to metal and I found a bit of a dodgy repair which I will address in the coming days ( this has been a common theme and I'll glad I took it down to the metal).

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Treated myself to a new tool to help to get into those hard to reach places.

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I had a couple of missing rear bumper irons so managed to source some at reasonable cost and also painted them

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Also started the repair of the fglass quarter panels but ran out of resin

IMG_20210111_214818.thumb.jpg.b25ad9ec378bbfb208ee422af2ba3980.jpg

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Has anyone tarted up their front spoiler. Mine has lost its captive nuts, anyone got a recommendation how to fix new nuts in place? Fibreglass? Some fancy glue??

Also the previous owner has half heartedly sprayed it in black, some is flaking off some is fixed firmly any recommendation how to remove the old paint without hours and hours of hand sanding?

I'm planning to colour code the spoilerIMG_20210110_210148.thumb.jpg.5f930fe4a47ad1bf0fc1088fea0b8324.jpgIMG_20210110_210143.thumb.jpg.1b9d061e40ef617889cd023d9e138dfb.jpg

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Looking god. Been busy there.

The battery box is a weld in job. Spot welded originally and more likely plug weld in the replacement. The mounting flange of the box sits on top of the bulkhead but annoyingly is sandwiched between that and the reinforcing brackets at either side.

I have never dealt with a plastic front spoiler so not sure if there is a recommended repair for the captive nuts. Although if glueing i would suggest epoxy rather than fibreglass. 

As for painting you should be able to remove the old stuff and use the primer intended for plastic bumpers before final finishing I would have thought. 

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Productive day today, first job of the day was to remove the battery box. Armed with the knowledge from a few youtube vids I girded my loins and dove in. It quickly became apparent that the guy in Triumph who spot welded these in decided it was never coming out. Welds on top of welds, welds directly next to other welds, what a pain.IMG_20210116_135357.thumb.jpg.b1f377a6e85ab28090f740a81037c1cc.jpgIMG_20210116_143722.thumb.jpg.a012048519856f160148de13b22dcb97.jpg#

 

Finally after much swearing, wiggling, hammering, more swearing it was finally out.

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It definitely wasn't salvageable...IMG_20210116_150241.thumb.jpg.2f6e814c8069fd525f4d0c5fea413569.jpg

The new battery box is ready for going in tomorrow (hopefully if I have time)

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Also managed to fix the captive nuts on the front spoiler by using expanding plasterboard bolts

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and put the spoiler in plastic primer

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  • 1 month later...

Lovely day for fettling and with the afternoon off it would be churlish not to roll the Spitty out and do a bit more bodywork slowly but surely etc.IMG_20210222_145855.thumb.jpg.161426809e21acaef452346950b7f5be.jpg

This evenings task was to put together the lights, I have been scratching my head over these for a while now but I had a light bulb moment and over light refreshment (geddit) they came together. The only issue I have is the seating of the floppy inner seal which doesn't want to sit right.

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Bit more done, finally got the door alignment something like on the passenger side, this has been bothering me for some time. I used the door supports I bought off ebay many moons ago.

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Also fins a problem with the finishers I bought from ebay a little while back, looks like I got a GT^ one instead of a spitfire one, so I returned one and now on the hunt for a passenger side spitfire finisher.IMG_20210227_105113.thumb.jpg.dbb9e3e1b36d25223bf14eb5710b5afe.jpg

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