EW Engine rebore and rebuild

[bazza]

Hi All,I have just had my engine rebored and new JP Alloy pistons and rings fitted,I have now put the engine together and fitted the flywheel,but alas! the engine only turns over a couple of revolutions and seems to come to a dead stop,also turning it the other way it does the same thing.Remember I haven,t tightened the flywheel right up and I,m using a ring spanner on the locking nut to try to turn the engine over.Oh dear what is happening will it be ok once I have the flywheel done up properly and the chains fitted will the engine turn over,I realise no one has a crystal ball but someone out there may be able to help.

Regards Bazza

[sidecar willy]

Hi..if the engine turned over before you had the pistons changed...check length of new pistons. The piston skirt may be catching crank???


cheers
Bill

[Stuart Lister]

Hi Bazza,

Do all the valves open and close as they should? If one of them is jammed, or the timing gears are binding...

Stuart.

[trevorp]

are valve clearances ok like stuart suggested it sounds like one valve out of adjustment have to be a long way out though

[bazza]

Hi , Remember some time back my problem of the engine not turning over on the EW after a rebore and fitting new pistons.Well the problem was the piston was hitting the top of the cylinder barrel or head whatever you would like to call it.Because I was using a very thin gasket paper it was thought that this was the problem as the pistons were the correct size etc etc.So where  :frown:do I go from here do I skim a few thou of the top of the piston and if so how much.I am a bit concerned about doing this as the piston may not produce enough compression,anyone with some ideas please.

Regards Bazza

[trevorp]

Thicker base gasket wont fix the problem?

[eddie]

Bazza,
            As the EW is a side valve engine with flat top pistons, for the pistons to strike the heads, either the pistons are too high or the barrels have been shortened - or both. So if you machine down the top of the pistons to give the original clearance, you will only drop back to the original compression ratio. Once you have removed enough to get the engine to rotate, you can check the actual clearance by applying small balls of plasticene to the top of the pistons, then check the thickness after rotating the motor. Aim for .030" to allow for any flexing of the crank.
          Just had another thought - if you have blind barrels (one piece head and barrel), does the rebore go right to the top or is there a step - in which case the pistons could be striking this step. Most boring bars require a special toolbit to rebore blind barrels!!
                                    Regards,
                                                   Eddie.