Speedysix Posted January 6 Author Posted January 6 15 minutes ago, Nick Jones said: Good work. The OCD is strong in this one You know the front valve is an exhaust valve right ……. (I have that t-shirt ) Thanks Nick, yes absolutely, I hope it pays Haha yes yes don't worry, The ports are seared into my brain the amount of time I spent working on that head back in the summer
Speedysix Posted January 6 Author Posted January 6 Back where it belongs! Quite the fight with the tunnel in, was just stopping the box from coming up enough! Thank God it's plastic and not the cardboard one, I think it would have punched through it There really isn't too much more to do until the head is machined, most I can do is fit the filter housing and new filter. The jobs are getting few and fewer! There will be a few puzzles left toward the end, things like finding the missing y piece for my 6 2 1 mild steel manifold, the air box arrangement( make one or modify a standard one to fit hs6), needles, springs, things like that. I honestly can't wait to drive it again 2
Nick Jones Posted January 6 Posted January 6 20 minutes ago, Speedysix said: Quite the fight with the tunnel in Wouldn’t have thought it possible! 1
Speedysix Posted January 7 Author Posted January 7 9 hours ago, Nick Jones said: Wouldn’t have thought it possible! There was no way in he'll i was taking any of that interior back out again, I have it perfect now and barely all fits 1
Speedysix Posted January 16 Author Posted January 16 So not much of an update but somthing at least. Turns out my recent spit mk3 purchase had a couple of 6cyl rocker shafts in a box, I have no idea why but it makes me happy the bottom one is the same as mine, the top one is diffrent, has capped ends, is it a mk1 gt6 one? Anyway, I went through the mk2 shaft and took off any good rocker arms to replace my ruined ones, noticed some have oil holes and some do not, can only assume this is a manufacturing change to save costs. you can see avove just how bad some of my rockers are! Id say it's a good mm deep! anyway, nee tuftrided shaft arrived from rimmer today. Started by unscrewing one of the little grub screws in the end and cleaning the shaft out with the compressor and brake cleaner etc, just to be sure. Disassembled the shaft and layed everything out in the right order, then reassembled onto the new shaft, one or two of the pedestals ended up being quite tight but a bit of oil and a very gentle tap with a rubber mallet seated them, I can only immagine some of the coating on the shaft must have been heavier there. I did measure all of the pedestal and arm bores of the ones that are going onto the new shaft and compared to factory manual spec, and of course physical inspection for wear/damage etc. The result, one finished rocker shaft! On a sader note, I went up to my friends place the other week when we had all the snow and saw my poor little spitfire in the field it will stay there for another month or so until the workshop space up there is free. Id like to get it stripped down and start panel work soon ish after the gt6 is done, but is going to need a fair bit! Jacob
flatter4 Posted January 16 Posted January 16 Good progress. I think the additional holes were a later addition to improve lubrication (rather than a cost cutting move). I've added the drillings to earlier rockers - 2mm ? The tips (which you show the wear on) are chill hardened - and the hardening is very deep (I once had a metalurgist friend section and test one), so it's possible to reface (and polish) that area. The rocker bores are often damaged (galling due to poor lubrication) and while you can bush them, there are remanufactured rockers available, that seem to be pretty good quality. ...and in my experience the alloy pedestals are always damned tight. Can't recal if you have removed material from the head (or are you waiting to do that......)? But worth checking the geometry when you assemble it all. Longer / shorter pushrods are available (Chris Witor is my preferred supplier) or you can use shims under the pedestals. 1
Speedysix Posted January 20 Author Posted January 20 On 1/16/2025 at 12:00 PM, flatter4 said: Good progress. I think the additional holes were a later addition to improve lubrication (rather than a cost cutting move). I've added the drillings to earlier rockers - 2mm ? The tips (which you show the wear on) are chill hardened - and the hardening is very deep (I once had a metalurgist friend section and test one), so it's possible to reface (and polish) that area. The rocker bores are often damaged (galling due to poor lubrication) and while you can bush them, there are remanufactured rockers available, that seem to be pretty good quality. ...and in my experience the alloy pedestals are always damned tight. Can't recal if you have removed material from the head (or are you waiting to do that......)? But worth checking the geometry when you assemble it all. Longer / shorter pushrods are available (Chris Witor is my preferred supplier) or you can use shims under the pedestals. Yes must have been, I think they came and went a few times, that sounds about right. I did look at doing this but in my case, the damage was so deep. I wouldn't have thought the hardened layer was that deep but then again they are solid lumps. I had looked at the bused rockers, quite a bit more pricey than some second hand ones! I don't know anyone who has much experience with them in a high mileage engine. Fortunately the replacement second hand ones suffered no massive scoring in the bores. Most of the time the shaft seems to take the brunt of the wear looking at 2 of the old shafts. They certainly are tight! Glad it's not just me! I think the height won't be an issue, the heads getting 30thou taken off, when I finally take it to the machine shop! so nothing that would need drastic changes, plus the higher lift cam and all should work out all nicely together, I'm sure i have some thin rocker shims somewhere in the box of gt6 bits.. Jacob 1
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