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Spitfire mk2 1147cc oversized pistons

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Hello all,

I'm just doing some research on new oversized pistons for my 1965 1147cc Spitfire engine which is currently at the machine shop being inspected and measured up. It currently has .030 oversized bores and will need to go to either .040 or .060 (depending on how the inspection goes this week).

I found this an incredibly helpful comparison between NOS and aftermarket pistons (http://www.wbclassics.com/tech/tr6/engine/triumph-tr6-cast-piston-comparison). My engine builder is old school and specifically asked me to find NOS pistons if I could and didn't like the quality of County, although I know their quality has dramatically increased over the last few decades (and possibly even overtaken AE).

I was wondering if anyone has a set of NOS .040 or .060 pistons so I can compare prices and see what the engine builder would prefer to use? I'm based in North Yorkshire and learning as much as I can, being in my early twenties, from those who have been engine rebuilding for decades so just want to see whats out there before I go in head first!

It seems like NOS valves, tappets, rings seem to be a little easier to find which is good. Are these considered the best quality or is there an aftermarket supplier in the UK thats best to buy these engine overhaul components from?

Have a look at my car on my profile, I did all the bodywork over university summer holidays a few years ago but now I'm on with a full mechanical/chassis/suspension rebuild during the COVID lockdown!

Many thanks,

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Hi Oli,

Jammy lad, having a mk2 Spitfire in your early twenties. Can't see any photos on your profile I'm afraid, this forum is a bit eccentric though. 

Sorry to be dense but are you asking to borrow a piston for comparison purposes, or for a set to buy? 

I haven't got any either way, but wasn't quite clear what you were after. 

Not sure what the 1147cc supply is like but I know it's hard to find any oversize NOS for the 1296. I've got a mk2 engine to rebuild myself at some point, so let me know how you get on! 

In terms of new stuff, I had Grant rings on my last rebuild and was pleased with them - bedded in alright and pretty much no oil consumption. Not sure how much choice you'll have with the small 1147 tappets but Newman Cams have a good reputation - are you changing the camshaft and do the old tappets look worn / pitted? If existing cam and tappets are in good shape you might consider re-using them. I believe you're supposed to keep the tappets in the same order the came out though, which might be difficult if you've removed them already.

Tranco valves come up on ebay quite often if you want NOS. I've used new from James Paddock and Canley Classics. Had an exhaust valve from Paddocks break in two, which was the push-on cap type used on heralds so I'm cautious of them now. It broke at the point the valve head joins the stem and destroyed the piston after only 1800 miles. Still makes me sad to think about!

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  • 2 months later...

5yr ago full engine rebuild late mk2 £860 spent on parts almost every think was replaced no short cutting .  some paddocks and  alot Rimmer , I returned some valves from paddocks as they visually looked poor quality  not shiny but dull and several were different lengths ! They didn't have any more in stock -does not instill confidence and I decided they were not really serious about stocking much early engine stuff so I went Rimmer. Pistons were a problem at the time and we had to buy direct from county I think . County parts were used including  cam. Engine has now done 20k oil usage is as per book, I'm very pleased .

We used tri metal bearings as per OEM think we had to buy direct 

Only thing of note was County cam lobes bigger so needed to shim the pedestals for sufficient clearance compared original cam

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