Lottie, a 79 full restoration Part 1/2/3/4/5

Discussion in 'Restorations' started by martinvention, Jul 12, 2015.

  1. A more thorough inspection of the barrels/pistons/rings/heads has revealed the need for replacements. Pistons were marked 85.95mm so I guess the barrels were re-bored some time ago. There is no lip at the top or bottom of any barrel and I had thought they might be good but the micrometer and feeler gauges do not lie and the piston to barrel clearance was over 0.3mm also the ring gaps very excessive when fitted anywhere in the bores. The rings were a good fit on the pistons which also showed little sign of excessive wear and indeed were very close to the stamped diameter, so I am guessing that the re-bores were a bit on the loose side, possibly to remove scoring? Next NDT showed a cracked head between the inlet and spark plug hole and beyond the valve seat up into the port area. So after much option research I have elected to fit a complete new barrel/piston/heads/valves kit from Coolair as well as new bearings and seals for the lower end. Looking forward to fitting all the nice new bits and in the longer term will mate to the transmission on a home made jig and run it for a few hours before a final check torque. Fitting to Lottie is still a couple of sheet metal and painting years away. Here is the duff head: Head Crack.jpg
     
    Last edited: Mar 14, 2016
  2. Turned the corner and firmly on the recovery phase. Lots of new engine spares; Engine spares ready to fit.jpg So before assembly a bit more measuring and balancing. The con-rods roughly tested using the John Muir (all thread bar and string) method: Con Rod Balance.jpg showed one to be different so I devised a more accurate measuring system: Weighing Con Rod.jpg Using a plank with a couple of shallow saw cuts to register with csk screw head in block screwed to bench and triangular bar on sales, the readings are magnified 5 fold. The errant rod (right in phot below) was No3 pot so no surprises there and it was obviously a replacement (consistent with damaged noted earlier) and not only a bit heavy but lacked slots to pein lock nuts, so this was corrected with the grinder and in common with the new weight tested pistons/rings/gudgeon pins provided some well balanced moving masses for each pot. Odd con rod.jpg
    All I have read about fitting pistons and barrels warns about potential damage when moving the crank, so I locked mine with all small ends at mid stroke and this still provided sufficient access for a ring clamp and no risk of unseating already fitted barrels. Here we are half way through: Half built.jpg
     
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  3. Coming along nicely. One of the rods on my bug was 6g heavier than the next heaviest one so i ground a little off it to make it match the other 3.
    I love engine building. Don't get the chance to do it often enough though. :(
     
  4. Thanks Zebedee, If you don't have to build them often then you must be doing it right. I hope I am in the same basket but sometimes a little doubt creeps in; I decided to check the valve timing on my freshly assembled 1600 and was surprised by the results until I checked the small print that said adjust tappets to 1mm gap to check valve timing. Then things looked better but the only figures I could find were a single ref from Haynes manual for all 68-70 engines, nothing definitive in Bentley or Idiots Guide. One reading was spot on, one a degree late and two 3.5 degrees late, I reasoned that with 100 teeth on the cam gear I might have got the mesh with the crank gear 1 tooth out. I agonized over the way ahead as I searched for better timing ref's but decides I had to see the timing marks again and here is the point of this saga and one I hope others will find useful: you do not have to strip the engine to see the valve timing marks. I removed the generator pedestal and baffle plate and using a small dentists mirror on a flexible rod and a pencil beam torch, I was able to reach down inside and confirm the 3 punched teeth were meshed properly, big relief. So I was able to move on from this point: Valve timing.jpg to the next agony!

    Crankcase Nut Locking. The Idiots Guide and some other online ref suggest the 6 big nuts holding the crankcase and main bearings together often loosen and indeed the middle pair on my engine came off much too easy! John Muir suggests 20 FPF nut lock but as I intend to bench run and re-torque I decided to add locknuts as all studs had a couple of threads exposed above the main nut. I had some old nuts which I split and ground flat, so for now this is where I am: Locknuts.jpg
     
    Last edited: Sep 3, 2016
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  5. Have you tickled the ports on those heads?
     
  6. Hi Paradox, I have to confess as they were new and not premium quality I decided not to play with the metal. The ports are actually quite smooth and the inlets a shade bigger than the manifolds so I will do a bit of scraping there to smooth the flow.
     
  7. @martinvention

    Nice posts with great information and Supurb pictures,
    thanx for posting them,
    They are always an interesting read
    :thumbsup:
     
  8. Thanks Art, and continuing with the intake porting issue I have done some work on the manifolds, faced both with fine paste on glass and eased out the upper area: Intake manifolds porting.jpg
    Top manifold done and bottom scribed for cutting/polishing. A note for AA Performance Head users, the dowel hole to register the manifolds is not present. I had to carefully mark up, and drill the new head flanges. Then I want to find the dowels in my old head.........missing, so had to make a pair from 6mm bright steel.
     
  9. Whats the gap between the two ports on the manifold for? I've seen a few manifolds with them and some without.
     
  10. I'm guessing Zeb, but I can imagine that when one valve closes the gas inertia creates pressure in that leg of the manifold which might result in a wave going the wrong way back towards the carb, so by having the gap the pressure dissipates into the adjacent leg?? However is is interesting to reflect upon the notion that some engineer(s) spent a lot of time modelling/calculating/testing/designing that little gap before it was considered worth changing all the tooling to make it, assuming it came later and was not removed when it was found to be useless!
     
    Zebedee likes this.
  11. Moving on a bit, another small issue I found with the AA heads was the presence of some unintended thin fins in the hole where the thermostat operating rod passes through to the fan casing vanes. These were easily removed with a 9 mm drill. Head Fins on  rod hole.jpg

    The rest of the rebuild progressed well and I was glad to complete the tedious job of bead blasting the tinwear and brazing on some repair pieces where mounting lugs had been damaged. So finally I got to fit the engine and gearbox to a test bed with some castors so I can move it about. Then after some wiring and plumbing to supply fuel and ergs it burst into life with a bit of a cough, good oil px and a very pleasant putt putt sound not heard for a long time. It will be a year or maybe 2 before it rejoins the body so plenty of time to test run and re-torque. Idle speed setting a bit of an issue at present with lots of conflicting advice in books/online, but latest read commends use of a vacuum gauge to set the throttle stop against the lowest cam. Previous setting attempts were made with throttle butterfly fully closed and relied on bypass mixture alone, which I can now see is not wise. Here is my test bed: Engine on test bed.jpg
    Test bed 2.jpg

    Weather getting good here in Somerset so back to bodywork soon with the new front and arches to do first.
     
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  12. Took Alternator/fan casing and carb off again. Having proved alt worked electrically, I replaced its 2 ball bearing races as both were suspect on earlier strip. To solve the poor idle I refaced the carb base and replaced the throttle spindle bushes for a more airtight fit. I also discovered some dirt in the idle jet!! probably the only/main culprit and the idle is now greatly improved, running on a properly set throttle stop and bypass screws. There is occasional hunting and I suspect I need to do some more tuning with the ignition timing. However I am back to sheet metal and preparing the offside front VW Brazil arch for fitting. Fletcher Gillett says to cut off a superfluous flange at the rear not used on German vans and to 'reprofile the step where it meets the floor as it is about 5mm too high. I was reluctant to flatten and rebend the lovely press formed step so decided to cut out a 5mm strip and weld to the correct shape: Cut Arch.jpg

    Welded arch.jpg

    I have removed the extra flange/bracket but have an idea to modify it and refit with some extra protection for the seat belt mount above. Piccies to follow.
     
    Last edited: May 29, 2016
  13. Hacked off all the rusty sections of OS front arch and repaired the cab floor and seat belt anchor point with seam welded 1.5 plate and made new anchor nut plate with downward facing flanges from 2.5 plate, the flanges for strength and also to take modification described below:
    Offside Arch and tub repairs.jpg

    There were a lot of spot welds to drill out but the wheel tub is thin and there is a joggle close to the welds so I was not happy with the recommended grind off option.
    So back to the Brazil arch with its extra bracket at the rear which fouls the vertical bulkhead bulge inboard of the B post. I liked the extra strength the bracket provides and decided that with modification it could clear the bulge and also protect the seat belt anchor point. So I tapered the lower part of the previously removed bracket and bent up a flange (top of photo) on the inner edge thus:
    Inner box flange.jpg
    and then I made a plate to form a closed box beneath the seat belt anchor point adding a large hole for painting and waxoil and a then a 25mm bung to seal it Inner box closer.jpg
    Finally all welded, Bonda primed, Tiger seam sealed and finished in Rustoleum, Stone chip later when all wheel wells repaired:
    Front arch inner box fitted.jpg
     
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  14. Nice bit of metal work shame it's under there :)
     
  15. Continuing with underside, back to bare metal, convert any surface rust, Bonda primer and then Rustoleum. OS outer cone on rear torsion bar tube pretty bad, so removed completely, the tube to chassis weld good on top but plenty of rust product on bottom section so ground to bare metal and seam welded before new cone made and fitted. This photo might be useful to some, it shows a cardboard pattern developed from a cone with a 120mm base diameter and 90mm diameter at a slope height of 25mm giving a curved panel ID 182mm OD 207mm and arc of 170 degrees. Using 1.5mm steel as original its easy to form by hand.
    Rear torsion tube to chassis cone pattern developed from cone base section: Rear Axle tube cone repair development.jpg
     
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  16. Now see I would be impressed Martin, but you have made the fatal mistake of using a cereal packet, you need to look at @1973daisey thread he uses Carling or in an emergency Fosters cardboard - your just too.........healthy:D
    Good work though, I keep meaning to pop in and see how its progressing. Paul
     
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  17. Hi Paul, you are welcome any time. I am afraid I was conditioned to cornflake packets from childhood, when they were absolute tops for making gaskets for Francis Barnet, James, Greeves and the many other motorcycles engine/gearboxes I played with before any attraction to girls and the demon drink!
    Best wishes Martin
     
    paneuropaul likes this.
  18. I have now started on the NS front wheel arch. As with the OS, first have to do a cab floor repair and also repairs to the tub under the seat and seat belt mounting points. I made a simple jig to press in a section of strengthening channel into the floor patch, bit of hardwood with a channel cut using angle grinder 1mm cutting blade and a chisel to finish the groove flat, then a piece of flat bar with rounded end screwed in place. Slide floor panel between bar and wood, line up channel and press in the vice. Seems to do the trick well. Useful tip if you do any pressing, always leave the final edge trimming till last to allow for material in the folds. Panel and jig: Cab Floor Patch.jpg
     
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  19. Dead useful for others that. I did the first one on ours with 2mm, wished I'd done it with 1.5 now as it was a nightmare to bend!
    [​IMG]
     
    art b likes this.
  20. This is dead useful for me! Our middle sill needs similar work.
     

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