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| naffsharpe (Nathan):
Here's a question for everyone ! I'm part way through the rebuild of my VW T4 ABL engine, for the second time, but this time because of an overheating problem rather than the traditional and well documented crankshaft/timing pulley failure. Having removed the cylinder head and after stripping it down to just the head I tried it on a sheet of glass while applying hand pressure only and was, in some places, able to ( just ) insert a 0.10 mm/ 0.0039in feeler gauge blade. This is the maximum that VW say is acceptable as deviation from perfectly flat/non warped. I then took a cast iron truly machined plate, wrapped it with 400 grit W+Dry paper, lubricated with WD40 and tried to flat out the areas where the 0.10mm blade would not insert. This took me down to 0.08mm, repeated took me to 0.65mm. This all took me about 2 hours, 1/2 sheet of W+Dry and a few calories. I blued the glass and tried the head but with only 0.35mm to play with the blue coloured the whole head. Having given you the preamble my question is this: The head is fitted using stretch bolts fitted in four stages, stages 1 and 2 are torqued, stages 3 and 4 are "quarter turn 90 degree" no mention is made of using an actual/accurate angular device. Stage 2 torque is 40nm. What torque figures should I be looking at for stages 3 and 4 or is everyone's quarter turn the same? Before any one asks , I have both printed manuals available and VW's dealer electronic manual (Elsawin) and none of them mention tolerances with stretch bolts!! Nathan. |
| doubleboost:
Make sure the bolts are well lubed CV grease is the best stuff to use Nice even 1/4 turn on each one Most cylinder heads have stretch bolts now It is very rare that a engine is repaired John |
| naffsharpe (Nathan):
Just seen my C--k up! Should read 0.065mm as a final read and 0.035mm as "leeway". Blame the Fathers day wine/Jim Beam, the fact that my son AND his GF remembered and any other excuse you have all used in the past !! Nathan. |
| naffsharpe (Nathan):
John. Thanks for your reply. I've not put a car into a garage for repair since October 1976 (Hillman Imp thrust bearing), unless I've been working away from home. If I can do it myself- I do! My feeling I is that I should go "JUST" past 90/o in the centre to take up that small amount. I worked for SLD pumps for years so diesel engine rebuilds are nothing new to me, anything from Lister AA singles upto multi cyl Volvo/Ford/Kubota/Perkins and now whatever we have! The only reason I posted was to find out how much tolerance was in that last quarter turn. Nathan. |
| DavidA:
Nathan, Just cut a cardboard disc to fit on your socket or extension. Make 4 marks at 90 degrees on the disc. Mark some place fixed place as a reference and, when you have taken up the slack, just turn the bar 90 degrees. One mans 90 degrees is the same as the next mans, or one of them is wrong. Dave. |
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