Wednesday, 20 November 2013

400 maintenance: camshafts

Another interesting piece of maintenance that came to light was the adjustment of the camshafts. Apparently one bank was quite off-set. How this could have happened is not known to me but it looks like someone did not do a very good job in the past. With a bit more off-set it could have resulted in nasty damage. Despite the off-set this was not noticeable when driving, even though you would expect a bit of power loss. Then again, with such powerful engine I don’t think anyone would notice it.
In fact for the purchase I did had the car examined by Italauto and it was not mentioned either. Apart from some minor things, which I already knew about, there was one thing that stood out; the compression test. One bank showed good values with roughly 13 bar for each of the cylinders. The other bank was more fluctuating per cylinder with lower values. I was told that a long drive beforehand would have made a positive difference in the results since the car had not moved for quite a while. This was mostly a theory and not factual backed up or looked into. There was no  sign of a leaking head gasket or such. So potentially it could also have been a valve issue, or worn piston and rings.

Looking back I have taken a bit of a risk here to go ahead with the purchase of this car without knowing the exact cause for this detected issue. But luck was on my side as this now  appeared to be a result of incorrect adjustment of the camshaft.
Crafty Stefan build his own tool setup to make the adjustment as correct as possible – matching factory standard or even better when it left the factory. See the supporting pictures for this undertaking and the results. Of course the new camshaft position meant also new adjustment for the
ignition part, which was consequently done. This also included a new pair of capacitors – preventative replaced.  And a new pair of contacts since these were slightly burned in. Last but not least the valve adjustment was looked into but these were all within margins.
After finishing the job another compression was done and both banks now showed 13 bar for all the cylinders. An excellent result for a 34 year old engine with almost 100.000 km run. What a difference a good mechanic makes. Thanks again Stefan for doing such a great job!

new cam cover gaskets


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