Question for the Engine Experts

Post by **PSL184** » Thu Jul 10, 2008 6:43 pm

Just dropped the sump on my 1098 to investigate what sounded like crank rumble. Took out one set of big ends also. There does not appear any crank movement either laterally or within the main bearings. The big ends don't look too bad and are marked as standard "STD". However, there is a lot of lateral play in the big ends (ie sideways across the crank. Also, I noticed that the oil strainer is only held at one end of the bracket not both ends - is this correct?
Any thoughts please......???
Cheers, Rich

Post by **bmcecosse** » Thu Jul 10, 2008 6:45 pm

Side play is normal - for clearance. Strainer should have two bolts for security but one won't be the problem. Take the centre main cap off - that's usually the worst main bearing - it will tell it's own tale.

Post by **bigginger** » Thu Jul 10, 2008 6:47 pm

Oil strainer is held with 2 bolts on a bracket running 'across' the pipe, plus screwed into the block, of course. AFAIK,there shouldn't be "a lot of lateral play in the big ends" though "

Post by **bigginger** » Thu Jul 10, 2008 6:49 pm

"Side play is normal - for clearance" I stand corrected once more - he knows more about engines than me

Post by **PSL184** » Thu Jul 10, 2008 6:54 pm

OK, I'll have a look at the centre main. Here is a pic of the big ends - How do these look to you guys?<br>

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Post by **bmcecosse** » Thu Jul 10, 2008 6:58 pm

Not too bad at all - although there has been some 'dirt' coming through the with the oil - you can see where it has scored the shell in line with the oil hole. Better check if your filter casing has the spring and plate inside - otherwise the paper/felt filter does nothing! If the centre main looks ok - and the crank feels smooth and has no 'ridge' in the centre - then I would fit new big end shells and bolt it all up.

Post by **PSL184** » Thu Jul 10, 2008 7:30 pm

Thanks for the advice. Attached a pic of the centre main. No sign of a spring or plate in the filter housing. I'll go check the manual to see what it "should" look like

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Post by **aupickup** » Thu Jul 10, 2008 7:35 pm

that one shows the copper ( or what ever it is ) so i guess that one is shot

Post by **PSL184** » Thu Jul 10, 2008 9:36 pm

Is that not good then ?
Whilst I'm there does any one have the torque settings for the mains and big ends pls?
Thanks again

Post by **polo2k** » Thu Jul 10, 2008 9:38 pm

60 foot pound for the mains and 45 for the Big ends.

Post by **bmcecosse** » Thu Jul 10, 2008 10:04 pm

That's well worn - looks like the big -ends may have been done before and the mains are original - it's Leaded Bronze and the big-end you show is Aluminium/Tin. You can change that centre main easily enough - and the front one too if you take the timing gears off and remove the two little screws - but the rear is not possible. Engine out to do a proper job i'm afraid. But you may get a worthwhile run from the engine if you change the ones you can get to. If there is no plate and spring in the filter - that will be the problem. They sometimes get thrown away with the old filter - and from then on there is NO filtering going on.

Post by **PSL184** » Thu Jul 10, 2008 10:37 pm

Hi BMC. I've found a spring and plate in the spares box but I don't have the steel washer and sealing washer as shown in the manual which sit on top of the spring - are these parts critical? Timing gear off !!!! Engine out !!!! Oh Man - This is turning into a major job

Thanks for the torque figures Ash...... Thanks BMC for depressing me

Post by **bmcecosse** » Thu Jul 10, 2008 11:36 pm

Sorry to depress you matey - but facts are facts. The steel washer can be any suitable washer - but the 'sealing' washer will need to be the right one. You can just pop it all back together and run it as is - no point replacing the big-ends unless you sort out the mains. It will rumble a bit - but as long as you don't hammer it, it will last a good while - enough time for you to track down a replacement. And all caused by a missing plate and spring in the oil filter. Oh dear.

Post by **PSL184** » Fri Jul 11, 2008 12:05 am

Such is life

Actually I quite enjoy been out in the garage playing with my toys so its no major disater really. I have an old Sprite engine and box lying around so I may rebuild that and slip it in. Do you know if the ratio's are the same in a Sprite box? or should I just swap engines over (nowt wrong with my box - yet!)

Post by **bmcecosse** » Fri Jul 11, 2008 12:09 am

I think some slight difference in ratio - but if your box is known good - keep it! So that's a plan - stick your engine back together with filter sorted - and then check out the Sprite engine before swapping them!

Post by **PSL184** » Fri Jul 11, 2008 12:14 am

Sounds good to me