"Off With Her Head!!"
The day has finally arrived where we have to dismantle Bandit's starboard V6 engine. It was never going to be fun but it's something that we need to do if this engine is ever going to run smoothly again.
When we bought the boat back in December of last year, we had no idea that we'd have to completely strip down the engine and have the heads re-machined and possibly new valves fitted. At this moment in time (before we've even touched the engine), we have no idea what to expect when we get these heads off. It could either be an expensive disaster or something as simple as a sticky/burnt inlet or exhaust valve. Our issues lie with number three cylinder. We've diagnosed that it is not producing the power that it should and Dad reckons we have a burnt valve.
We woke up at 7am today and headed straight for the boatyard. We packed all of our new tools and whatever else we needed such as cardboard to lay the oily parts on without destroying our expensive teak flooring.
We arrived 20 minutes later and got straight to business. We placed aside all of the cockpit seats, removed the stainless support poles and then packed it all away in the guest cabin so it was out the way. Then, it was time to focus our attention to the engine itself. Before even touching the engine, we got everything we needed out including a notepad and some small sealable bags to put bolts in and label them. This way, we'd be sure we know what everything was and where it went.
Dad began by removing the spark plugs and distrubutor cap and placing them aside down below. We decided to lay everything down on the saloon table where we could keep some sense of order so we knew what was what. Next, it was time to loosen up the hydraulic steering pulley and remove the drive belt. After that, we drained the engine coolant water from the heat exchanger out into a large bucket and placed it aside. We had only recently replaced the antifreeze so we thought we might as well keep it and reuse it when we put the engine back together. We then spun the heat exchanger around a bit so it was out of the way from the cylinder heads and rocker covers. After that, we removed all the large pipes and then proceeded to loosen the inlet manifold bolts. After realising we could not get the distributor out due to lack of space, we had to remove our new carburettor. One carburettor and a distributor safely set aside, it was then time to lift off the inlet manifold and place it down below. Then, we removed both exhaust risers. We expected to take them off and find them to be in awful condition. To our surprise, they are in decent condition so we save ourselves 300 quid. Now it was time to remove both exhaust manifolds. Annoyingly, we clearly didn't drain all the cooling water so a lot of green coolant then found its way into the bilge. I took these outside and placed them on our pontoon so they could drain out before putting them in Dad's boot.After the manifolds and risers were safely removed, it was time to remove the rocker covers. I put these aside and then Dad proceeded to remove the twelve rockers, putting them and their nuts into a large container, labelling each one so they go back to the same cylinder they came off. After these were out the way, we removed all the push rods and placed them into two bags, one for the left-hand side rods and one for the right. Now comes the job we were here for; removing both cylinder heads.
We eventually removed both heads and found a vital piece to the puzzle. Dad realised that the middle piston on the right-hand side of the engine was clean and so was the bore. It was clear that this cylinder had not been firing correctly (if at all) for a long, long time. Another thing we realised after getting the heads home is that the exhaust valve for number three cylinder was wedged right the way in, unable to open and close properly (by the looks of things). Dad told me he was sure this was not right and there was something wrong. To make this worse, the valve spring compressor we had purchased off eBay was not strong enough to compress the springs so we weren't able to remove the valves like we had planned. After removing all the old gasket from this head, Dad realised a lot of corrosion inside the head itself. This is a huge problem as we are unsure whether this can be repaired.
So, not looking too good at the moment. We're now very unsure what our overall problem is and now we're both panicking about our right-hand side head. It might either be a welding job or if that's not doable, a new cylinder head. Bugger... This was worse than we had expected. We've given up today so we'll see to it tomorrow when we both have a little more patience to think about the situation. It's been a stressful day but I feel like I've learnt a lot about engines in general. I'm only 17 years old so the mechanics of an engine to me was very foreign. I'm happy that I understand a bit more about how the engines work as I'm sure this will come in handy in my future.
It's not nice seeing one of our engines so naked. I just hope we can mend it without cashing out thousands of pounds. If it really is this expensive, we'd still consider new engines. Whether that be the more modern Volvo Penta 4.3 GXI petrol engines or a pair of diesel engines. Petrol would be easier to install to the existing boat, but then petrol. Diesel engines would be incredibly economical and cheap to run but this would involve a hell of a lot more work and money.
Decisions decisions decisions...............
|After removal of inlet manifold, exhaust risers and exhaust manifolds|
|After removal of rocker covers and left side cylinder head|
|After removal of right side cylinder head|
|Front view of Bandit's naked V6 engine - everything removed|
|PORT SIDE ENGINE|
|Port and Starboard engine comparison|
|Top view looking at pistons and camshaft/tappets|
|Numbers 1, 3 and 5 pistons (#3 looking rather clean)|
|All the removed parts in the boot, ready to be taken home and cleaned|