I posted recently about a loud knocking noise on starting up my 1600 Aircooled CT engine. The noise disappeared after a few minutes of driving and hence most people were of the opinion it was a leaky tappet.
As advised I did an oil, filter and strainer change and flushed the engine at the same time. The problem seemed to worsen progressively, the knocking was present everytime I started her.... regardless of how long she'd been sitting for (whether it was 10mins or 5 days!). The noise would however always disappear given a few minutes driving.
As well as this problem I also noticed another problem..... after about 20mins of driving I would get a metallic rattle / swishing noise from the engine. Having thought long and hard about it I wondered whether this could be a cylinder leak, maybe as the engine warmed up and the cases expanded the leak would appear (noise only present under load)?
I decided today to check if the cylinder heads were tight and have a go at adjusting the tappets.
After stripping down the necesary tin work and ancilary components I started tightening the cylinder head nuts to the 25 nm stated in my trusty haynes manual. I found all the head bolts were loose.... some allarmingly loose (finger tight!!).
Once these were tightened I followed the manual and tentatively adjusted the tappets. I followed the book exactly, adjusting cylinder 1, 2, 3, then 4. I found that all the adjustment screws were wound in around 6 turns from the just touching the valve stem point. The book stated 2 turns and I have read in the forum that some surgest only winding in 1 turn. I wound them in 2 due to the massive adjustment I was making.
I put her back together in the p*ssing rain and was scepticle as to how likely she was to start!
She started up first time..... the loud knocking noise that was previously always there at start up was gone! On the down side she is as little more tappety now, however I haven't managed to take her on a long run yet so this may improve given time.
Unfortunately a new problem has now arisen, she now idles quite eratically and now has a tendancy to stall quite frequently at junctions. I'm guessing this is down to the tappet adjustments I've made.
Can anyone shed some light on all this. Was the knocking down to the loose cylinder heads or pooly adjusted tappets??? Why do I now have the idle problem?
I feel like I'm making headway with this engine but fixing one problem seems to create another!
Sorry for the long winded post. All help and discussion on these little problems and findings would be welcomed! I like to delve into engines and 'have a go' but I'm no expert..... hence all opinions and advice are welcomed.
P.S. The CT engine is a recon unit with 1500 miles on it.
Many thanks,
Gareth
www.charitytour.co.uk
