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  • Birthday September 21

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    1978 S1

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  1. 0.050 inch is a lot to take off a head and suggests serious warping occurred. Have the cam carrier mounting faces also been machined? There may be more issues than just piston to valve clearance with this head cheers Rohan
  2. Yes I would check clearances and then do a leakdown test when the engine is hot and lost compression to try to see where it is leaking to
  3. clearances especially on the exhaust will close up when the engine is hot
  4. I dont think you would see any change in oil pressure with changes is cylinder compression pressure Its easy to get a valve clearance wrong or for a follower to jam or for a shim to get moved off the top of the valve stem or for a too thin shim to cause problems with clearance so I would double check all of those areas
  5. Yes maybe a valve sticking open when hot ( maybe a bent stem) also I would recheck the cold clearances on No3. I assume no head gasket leak issue when hot with gases into the coolant system ? cheers Rohan
  6. My very one of the last S1 cars had the automatic belt tensioner. I thought this was standard on S2 cars ? May you're car had a change some time in its history back to early S1 manual adjuster spec ? Shortening the stud and using a half height nut should get you belt clearance if needed with you're current set up ? If you want to go that way cheers Rohan
  7. A bit of heat releases the bond with expansion of the alloy. ultimately enough heat will melt the Loctite but you need to be careful not to over heat the alloy. Best to use a hot air gun with temperature control
  8. No outer race should ever be allowed to spin. Using a suitable bearing fit compound is clearly a good idea especially if the fit is at the loose end of the typical tolerance band for this sort of bearing in an alloy housing running at say 130C maximum. cheers Rohan
  9. You have looked at the insides of more of these gearboxes than me, so its good I am not a betting man If they were machined separately it would be interesting to understand the setup method used as I know of no practical way to do it to the accuracy required to get the two halves centre lines aligned with each other and in the right location versus the diff centre and with the correct bearing interference fit. But if done separately it certainly would help explain the assembly issues experienced. cheers Rohan
  10. I find it hard to believe that the output shaft bearing supports between the GB and bellhousing were not machined as an assembly. May be not on the centre line of the split or on the centreline of the diff carrier but i believe impossible in a practical sense to do separately rather than as an assembly. A measure of vertical versus longitudinal diameters would confirm if not a a true circle - but hard to do. Certainly if on assembly the output shafts are being moved as the centre line of the output bearings is a few thou different form the diff carrier centreline the preload would be affected cheers Rohan
  11. When the gearboxes were made the bell housing and gearbox casing would have been bolted together and then the 80 mm hole bored. Nominally this bore would have been centred on the split line but it appears there is some ( systematic?) small error in the machine setup used to do this boring so the centreline of the bored hole is moved 7 thou from the split line to the gearbox side. This type of tolerance / error is not uncommon in machinery fabrication which is why it is always wise to check the location of the centre line of bored holes precisely as done, rather than assume the split line is also the centre of the hole cheers Rohan
  12. Most synthetic and mineral base oils actually tend to cause rubber seals to shrink so appropriate rubber swell additives are added as part of the formulation in quality oils to counteract this. "High mileage" engine oils or supplementary lubricant additives have additional swell additives to help counter wear on seals by additional swell to minimise leakage from places like the rear main seal cheers Rohan
  13. I dont believe the Polyol Ester molecular size is significantly different to any other lubrication oils. In any case fluid leakage does not really relate directly to molecular size but more to bulk properties of the fluid such as viscosity. In my experience with MT90 in my S1 esprit at least its leakage rate is similar to other modern synthetic oils. If leakage is a problem then you have something wrong that needs fixing. The common leak point in the Citroen boxes is the gear change shaft. You put up with it normally as its small or you fix it if you really want a totally oil dry rear of your transaxle. The advantages of polyol ester base oil are huge in terms of thermal stability and lubricating properties so even if they did leak a little more they are worth it in my personal opinion but from my experience they dont. i will stick with MT90 cheers Rohan
  14. You could talk to these people - never tried them but looks like what you need cheers Rohan
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