knocking 170

[wdf]

okay, i finally got it fired up today... ran lovely, apart from a knocking that sounded suspiciuousely like a con rod.....


anyway, i stipped it all to bits, only to find that the con rod cap is like brand new, and the bronze bearing on the rod is also virtually perfect.....

so, my question is, given I have stripped everything, and it is all perfect, then what is this odd noise??? or does a 170 actually sound like that.


it sounded internal in the area of the conrod/crank etc....

[wdf]

upon further examination, rotating on the bench etc etc I have come to the conclusion that the only thing that could be causing this is actually the bits inside the flywheel.... basically, after re-assembling the gear casing, and rotaing ont he bench, something inside the actual flywheel housinhg appears to be rubbing, which, when rotated vigourously then gives a knocking.

Next problem, how to remove the flywheel on the 170??

there is nowwhere to put the jaws of a puller...nor are there any convenient holes with threads....

the only method I can see is to grind away some spaces from the ali baseplate to allow the jaws to get underneath the flywheel.

it appears there is no actual reason for the edges on the baseplate, as the only thing that sits on it is the alternator, which locates only on the corners...

[rosbullterier]

Please don't try to remove it with the puller, I am interested in what you find and how it runs when you've put it back together.
The flywheel is removed in the same way as the standard Century by one person gripping the flywheel and the other giving a sharp heavy blow to the flywheel nut (I understand with the piston at the bottom of its stroke)

[rosbullterier]

Yes it is best if you use a standard flywheel nut from a Century!

[wdf]

as I suspected, the fact that the flywheel was "rubbing" on something was actually caused by the fact that the crank is slightly bent.... the fact that before I started doing anything to this there were the marks on the flywheel indicating someone had been having "a go" at this before..... and most likely been whacking the flywheel with something and hence bent the crank...


Anyway, so the problem now is.

1. I have a totally perfect 170 apart from a bent crank. (ie the con rod + cap are perfect...)....

2. Do I a: locate another crank, or b: build some sort of hybrid?


From looking elswhere on this forum, and also trying to match up parts it looks like not a lot will fit from say an old silver century onto the 170..... I was thinking of building some sort of retro hybrid... with 170 block + carb, and then old fashioned gear housing + flywheel etc etc.....

what about matching up cranks? con rods? pistons? bores etc etc.


to summarise, I now have the following.....

1. A 1961 century short shaft (with slightly dodgy carb)
2. A silver century with broken handle bracket (and slightly dodgy carb)
3. A perfect 170 (with perfect spare cowling!!) with a bent crank.

Is it possible to build some sort of retro high performance century????


Any ideas???

[rosbullterier]

I understand the Centuries are completely different from the 170 internals and crancase.
Take the 170 crank to a good machine shop and straighten the crank (and have a phosphor bronze end cap made while you're there, I'm picking mine up next week)

[wdf]

ok, I will see about getting the crank straightened.
.

[wdf]

could you email me the machine shop you are using?

it maybe more useful to use one that has done this before. ie. if they have already done you a con rod cap they will find it easier to do the job again.

[rosbullterier]

I'll pick it up, try it out and then ask him whether he wants to become an end cap manufacturer.
Others have suggested a batch could be made - I asked him if two would be as easy as one; he replied two would first need the hole boring, parting into two halves then the two halves soldering together to finish the caps. I don't think he has the equipment for batch work.
The firm is in Plymouth, I'm sure you must have one good enough near you.

[wdf]

looks like there are fuirther problems..... upon looking on ebay for baseplate, ignition module, and flywheel.... they all look different to mine.


all three items on mine look suspiciousely new.... in fact, they look like they are less than a couple of years old....

the ignition module i found on ebay looks totally different, similarly,even the baseplate has not got a cutout in it, whereas mine has.

i checked the crankshaft again, and whilst although I though it was bent, it is only slightly wobbly, ie, it is actually barely noticable. though still sufficient to make the flywheel rub on the ignition module.


I have now also cross referenced with

http://www.seagullparts.co.uk/ignition2.html

and it looks like whilst my 170 is a 1984 model (the serial number is ENL 151 B4)

it looks like I have the later Mk4 wipac ignition..... similarly, my flywheel has a groove in it, indicating it is also a mk4 flywheel.

[rosbullterier]

Yes as I mentioned previously the 170 is completely different to Centuries. I don't know whether it is the same as QB's.
Anyway, two questions: are you sure the flywheel hasn't been distorted with a puller, and, have you checked John Williams for a S/H crank/ flywheel to suit.
With the number of 170 conrods disintegrating, there must be good spares about.

[wdf]

I will contact John to see if he has the correct ones available.