GBW

A previous thread relates to my troubles with the crankshaft pulleys. There was concern expressed that adding extra pulleys could unbalance the crankshaft leading to a possible failure. Taking note, I became sensitive to NOISES. In particular I believe I could hear a Clank every other revolution. Must be a big end I thought. MY very poor hearing has been of no help in diagnosis and the use of the screwdriver "stethoscope" likewise helped not at all. Relating the concern to a friend, he remarked that sometimes a failing injector can sound similar to big end rattle. I loosened the feed to the injector on cylinder one where I thought the noise came from and the clank disappeared. I do realise that not allowing the cylinder to fire could have other consequences (e.g. in terms of bearing loading) but I am encouraged to believe an "engine out" may not be necessary. Views please. scope"

I have this morning received from Fischer Panda UK another more detailed workshop manual with a view of the push rods showing they are indeed as I described - decompressor operates on the inlet valve. I van now complete the rebuild. Thanks to all for the help.

I have three manuals but, frustratingly, none shows the arrangement I seek. There is a steer - "Intake push rod to be placed Into tapped top hole closest to cylinder". I can't find a tapped hole and "top" is difficult to understand as they are both at the same height. Both rods are identical in length. "Closest to cylinder" implies the inlet valve is operated by the decompressor. The valve lift from the decompressor is minimal at 0.8 mm. There is around 1.4mm clearance. Close! Is it fundamentally a good ides to (possibly) fill the inlet manifold with unburnt fuel? Better surely to dumP it through the exhaust manifold? However, this concern must apply to all valve based decompressors?

I bought a used one with a declared fault. There was water contamination of the oil. Suspecting the cylinder head gasket (in ignorance), I dismantled the head. There is no gasket but there is a copper ring that looked fine. The two red O rings that connect the water circuit were shot and have been replaced. All fine but! The valve push rods are operated by a cam on a shaft in line with the crankshaft i.e. "fore and aft". The valve rockers are on a shaft at right angles to the crankshaft. To connect, the push rods follow a 90° twisted route . They are enclosed in a protective shroud. This shroud detaches when the head is lifted. The push rods then become free and the original arrangement is lost. The conundrum commences. The rotation of the crankshaft is counter-clockwise when viewed from the power output end (in my case, the generator coils). There is a decompressor. In my very limited experience, decompressors operate on the exhaust valve(s). If I arrange the pushrods to achieve this, the firing sequence is wrong - inlet, exhaust, compression, fire. If the decompressor operates on the inlet valve, the sequence becomes correct. Am I suffering a mental block? The Fischer Panda UK agents have been very helpful but it is the weekend and I don't expect an answer for a few days. Any views please?

The photos in the beat listing show the complete generator including the innards. My apologies for posting in the wrong section - which would be best? I nave to confess that the boat is sea going (although it has spent time on the canals) and the heat exchanger would be sea water cooled if external.

I have one of these restricted to fresh water cooling. It seems from the manual, that the sea water cooling version uses the same innards plus a self contained heat exchanger. I have tried to purchase same from Fischer Panda without success. Another option would be to instal an external heat exchanger (which might have some side benefits - like water heating). Anybody any experience of this conversion please? Although the UK agent has been very helpful, he cannot solve my problem. This was the source;- https://www.ebay.co.uk/itm/325336127309 The fourth photo shows a sleeve on the right which, I believe, accepts the cylindrical heat exchanger.

I retapped the end of the crankshaft 5/8" UNF as advised. With around 5 inches space between it and the bulkhead, and using a spanner as a wrench, it was not easy. I used the new boss as a guide and the tap eventually picked up the undamaged thread. The bolt head was cross drilled and wired to two pins through the washer into the outer pulley. It ran true. I didn't replace the belt to the large alternator to ease the load. The repair got us home to Cardiff.

I did say! The inverter. The various mains powered items on the boat draw 1000-1500 watts. Turn that into 12 volt watts and you will see the reason. I better solution I agree, would be a separate generator which I have but is petrol and needs to dug out of the deep locker. If I could find a small diesel generator that could be installed in the stern cabin, that would be great. I could put up with the noise.

Not really. The three pulleys are locked together by dowels (as explained) and sit snugly on a boss with appropriate diameters. The bolt pulls the lot together and the boss should take the side load. However, you lot have filled me with fear! Is there any other way of reconfiguring this arrangement? Could I just drive the big alternator from the crankshaft with the original drive to the alternator and water pump left undisturbed, and then drive the Jabsco from an additional pulley on the big alternator? That would reduce the overhang on the crankshaft. Alternatively drive the Jabsco from an extra pulley on the water pump. If (when🙁?) the crankshaft fails, I can modify the standby engine according to your collective advice. It would be hard not to have the big alternator as its 130A output is a boon for running the inverter.

Er........ not in pieces - in the boat!

The mystery deepens! (and my frustration increases). The bolt from MG owners Club does not want to start. It is 5/8" X 16 tpi. It is very difficult to gauge an internal thread without a plug thread gauge. However. On the refurbished engine I have threaded into the end of the crankshaft a piece of 5/8" diameter soft HDPE. This has created a measurable thread on it. It is 18tpi! I.e., 5/8" UNF. The remains of the bolt from the installed engine measure 16 tpi. The boat is currently at Ilfracombe awaiting the fix. The original mod (by me) was to create a boss over which the Jabsco and alternator drive pulleys fitted and which had a threaded spigot on the end. For some inexplicable reason, the whole lot unscrewed leaving the engine without seawater cooling. (In the middle of Bridgewater Bay with a fast ebb and 49 metres under the keel is not a comfortable experience). I think I will drill through the boss and make two bolts, one UNF and one UNS and hope one of them will serve. Many thanks again to all. The problem with old engines is that you don't know the history.

Easy to check if you have one in front of you!

I've ordered from MG. I'll let everyone know if it fits! The Calcutt reply was "The Crank pulley bolt has a Unified Thread, I don’t recognise UNS".

Tracy tools can supply the tap and Calcutt can supply the bolt. I have asked the latter if they stock a long version. Thanks everyone for your help. MGOC have offered the information that the MGB bolt is indeed 5/8" UNS. They can supply the damper as well.

I will try but I need a longer one than standard to accept the extra pulleys. I'll give them a call. Thanks.

Assuming (!) the 1.8 litre petrol engine (as fitted to MGB) has the same crank, it seems the thread may be 5/8" X 16. This is close to UNF (which is 5/8" X 18tpi). Searching suggests UNS (5/8" X 16tpi). Finding a die for this has so far proved impossible. I will have to resort to thread cutting.

I have a spare engine in rebuild. That has a harmonically balanced pulley but that currently fitted to the boat has not. Interesting. Perhaps with low revs, <1500, the engine will be safe.

The extra pulley was added by the marinising engineer (Norris & Son). I added a further twin groove pulley for an additional alternator. The original extra and my additional one are all pinned together with dowels to take the torque. (The thread is right hand anyway so a screw under load would undo. There is/was an option for a starter dog). The engine has run in this fashion for five years.The crankshaft is still intact (!) but I don't know if there is additional unbalance or not.

Anybody know what thread this is please? I need a special made to take an extra pulley and the original has gone missing.

It is impossible to fit a spanner into the space available. The surrounding casting means a box type spanner or socket seems the only solution. A Torx 10 fits one screw but the other is smaller. You are correct about 12 sided though (I have a spare in my workshop). Commence search for 12 sided box spanner! Later;- A butchered 1/4" ring spanner (OD of the ring ground down) fits. My sockets are 6 sided 3/8" and below. Even later;- Removing the assembly confers no rewards. Maybe it is a push fit but pulling invites damage. It seems possible to add lubricant through the idling damper access although it doesn't seem to loosen it.

Mine has become stiff and the solenoid sometimes fails to actuate it. I read somewhere it is not uncommon and needs freeing. I have eventually realised that the screws holding the assembly to the rest of the injection pump are Torx headed. However, one is T9. That size seems impossible to source. Any help please?

Thanks all (especially Tony). I thought it probable that the force on the chain derived from oil pressure but the notches baffled me. Now it all makes sense. I have a spring and I'm sure all will be well.

On reassembling my re-conned engine, I find that the spring in the chain tensioner has gone missing. The tensioner itself, looks fine. As they are only cheap, I ordered one from MG Owners Club spares (I am a member). Unfortunately, they are out of stock. I have a box full of springs. Which should I select? (I am intrigued by the notches in the "piston").

My 1.5 certainly does.