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[Greenbat]

I'm tackling a 1960 crusader for a friend. So far it's been an utter nightmare, and the latest development needs some expert advice.
I had a look in the cylinder and bottom end. Oh dear! It appears the valves have walloped the piston, presumeably due to being fitted the wrong way round. Pictures and description here: http://oldnailsandswarf.blogspot.co.uk/ ... d-joy.html
I'm guessing the piston and conrod are scrap, but I thought I'd best check. I really don't want to do a full strip! What do you reckon?

[Gwilly]

Hi Greenbat, i've read some of your stuff on another classic site over the years so i know you are fairly handy with the tools and know what your doing.

However your working on a pals bike and will be handing it back to him as a going concern.

Could you be sure that the rod wouldnt give out at speed... What other lashups/horrors are inside this motor..... If six people on this site said yea go for it, no problem.. Would you be comfortable with that??? Its got to be stripped and inspected.. no short cuts.

Every bit on this bike seems to have a defect of some sort, why should the motor be different..

The barrel is an early type maybe 59.. the head is later maybe 61 should have 2 1/4" bsf allen screws securing the pushrod tunnel, hense the silicon...yuk. The inlet valve was larger on the newer head aswell, has this dinged the piston?? Strip it and rebuild it.. theres only one of each major part.
Not like its a 4 cylinder kwakhonda.... cheers gwilly.

[Howzie]

Hi Greenbat,
I to had a nightmare when I started my 1959 clipper, boy was it a mess, in the end I had the engine in & out of the frame 3 perhaps 4 times ending up with a rebore, new piston, big end shells, new crankshaft bearings etc, etc.
I to thought a top end rebuild, valves, springs etc would be Ok but no no no.

Take the bull by the horns and strip the engine right down, getting everything checked over, you may think it's a pain in the a**e but do it right first time & you won't end up like me dragging the bloody engine in & out.

Cheers.

[Alan R]

Hi guys---------- Fair brings a tear to your eye, eh ?.. GREENBAT, collectively those on this forum who have travelled this road before understand just WHY you are asking about continuing with a full strip----it's because you know you are going to HAVE to----especially as it's your mates machine..So come on, get STUCK-IN and keep in touch via this forum...Incidentally the word "Front" on the crown of a piston is normally offset in its' positioning such that you can place it nearest the exhaust valve....Whenever moving engine parts touch there is a transfer of kinetic energy with all the usual events. You just can't be sure as to their suitability for continued service, so >>>>>>>>---- you know what you have to do....Keep your pal in the loop so you're not working alone and he'll fully understand your problems.....I fully agree with GWILLIE and HOWZIE...so that's 3 of us then !! PS--My No.2 Bullet has a loose gudgeon pin bush, so that's a full strip as well !!

[Greenbat]

Thanks all! Yes, alan you're right, I'm desperately looking for an excuse not to and finding none! BTW look at the picture of the piston, the front writing is slap bang in the middle. Sounds like it's got a muddle of later head, early barrel and god knows what piston, which might be another cause of valve/piston over-friendlyness...

[big al]

Hi alan R. Gudgeon pin. I did the very same job on a friend's Bullet. This was done with the engine in situ. No need to remove the engine.
Albert (Truro)

[Mark M]

Greenbat, as others have said, all the signs point to a full strip. The up side is that all the parts are available from our Hosts except the later GT rod which is much tougher and won't be a problem under normal use. They do come up regularly on Ebay though. The engine is quite a sophisticated design for 1956 (when it originated) and isn't suitable for 17 year old Owners, back in the day, to work on! You really need to buy a Manual if you haven't got one, and definitely read the article titled "250 Engine strip" in the Technical Notes on this site. This was written by Jack Gray, a well known Enfield Dealer who built many fast 250s back when they were new and probably originated the GT look. These are tough little motors if built properly and will reward the effort but sadly it will cost a lot more than an equivalent Bullet rebuild!
REgards, Mark

[Greenbat]

More things I've found: http://oldnailsandswarf.blogspot.co.uk/

I've never seen so much silicone!!

[Alan R]

------------try page 3 !!!

[Alan R]

Hi guys-------- Hi Big Al}--- a re-bushing of the small end has already been done by a PO....and it's that bush which has now worked loose and run the aluminium con-rod hole oval.. The effective wall thickness is about 1/16" so it's a con-rod change, alas..... Pity the design isn't a clamp-up style of small end with only the piston having the rotation within it ....much cheaper to do that way..