fitting centre main bearing strap...

[picky]

Ive removed the sump and I intend to fit the centre main bearing strap ive bought recently. Ive been told that I have to machine or file flat the top of the bearing to make it fit, but on mine there is a bolt in the middle of the bearing that secures the oil pick up pipe. As the pickup pipe is held in two places could i remove the middle bolt altogether? as the strap will not fit with it in place.
Thanks for any help....

[Alec]

Hello Picky,
I've never done this, but I would suggest making another bracket to replace the original, perhaps from one of the main bearing bolts.
Manufacturers rarely fit things unless they have to.

Alec

[les]

I agree with the post from Alec, also if the cap is not a machined finish I think it would pay you to get it done, it needs to be perfectly flat and parallel to accept the strap.

[ColinChandler]

Hello,
I've strapped the bottom end of my 1275 Midget engined minor and its pretty straightforward. I bought it from Minispares so it came complete with decent bolts. The existing ones are obviously not long enough any more. Then it was off to my local engine rebuild place and they skimmed the existing cap flat for me. It does need to be properly flat. I queried the oil strainer tab getting in the way and the engine bunch said they always removed the lug. It obviously leaves it with just one but they said they've had no problems and neither have I. All it needs then is a thorough clean to make sure there's no nasty bits in it when it goes back together and 'jobs a good un.'
Cheers, Colin

[Alec]

Hello all,
I would go with my earlier statement, manufacturers do not waste money with unneccesary bits. If it were my engine, I would probably weld a tab on the steel strap and secure the pipe to that.
Jaguars lost their first Le Mans due to fracure of the oil pump pick up on all the team cars and all XK engines after that (including road engines) had an extra pipe clip.
Your engine, your choice.

Alec

[bmcecosse]

This is a fairly serious engine mod ! Only done for very high revs. The cap needs to be very accurately machined (filing is NOT good enough) to leave just a tiny 'pinch' gap between the new strap and the old bolt hole platforms - and obviously the new long bolts must be the correct quality (I used Allen Cap screws when I did this years ago). Is it not maybe possible to re-shape the pickup pipe and somehow drill and tap the strap - and fix it onto the side of that ?

[Alec]

Hello Bmce,

" (filing is NOT good enough)".

try telling that to an old fashioned bench fitter.

Alec

[picky]

Colinchanlder is right that removing one of the supports will 'work' but I feel that the idea of fitting the centre strap is to increase the reliabilty of the bottom end, not detract from it! It should be relativly easy to bend the support, and widen its mounting hole so that one of the main bearing bolts holds it in place. Again filing the bearing flat will work, but having it machined flat is likely to be more effective.
Thanks everybody for your opinions!
Tim

[bmcecosse]

Risky filing it ! If you don't get it perfectly level you will do more harm than good. But why are you doing this mod ? It's really only done for engines that are going to be hammered well above 6000 - is this your plan ? And don't try to hold the oil pipe bracket with a main bearing bolt - they need to go straight down onto the strap.

[Cam]

Machining is definately best. Having a centre strap is a good idea, but so is having the moving parts balanced and fitting a crank vibration damper too (in fact more so).

[bmcecosse]

I would imagine 1275 engine has crank damper as standard - it is indeed essential !

[Cam]

Yes it does.

[picky]

will a standard crank pulley from a 1275 fit straight onto a 1098??

[Cam]

I have never tried it myself personally, but I'm told that it fits no problem.

[les]

" (filing is NOT good enough)".

try telling that to an old fashioned bench fitter

I've seen some filing and scraping done by good engineers and the end results were virtually perfect!
I suspect that these people are now few and far between.

[Alec]

Hello Les,
I agree, we have lost a lot of the skills that were once quite common.

Alec

[57traveller]

[quote="les"]

[quote]I suspect that these people are now few and far between.[/quote]


There's still some of us around Les!

Third time of asking - why aren't the quotes working correctly for me, surely somone has an idea?

[ColinChandler]

Hello everyone,
This ones turned out a few opinions and having read all the posts with interest, I wonder if I should now make a new 2 holed bracket to give the oil pickup on my engine more support. Just to be on the safe side for as you say, they dont spend money putting 2 fixings there if one will do. However, one thing I'm curious about though is not using the mains bolts as fixing positions. bmcecosse mentioned it and the original fixing on the bearing cap was indeed a seperate tapped boss but I'm curious about the logic behind it. Anyone have any ideas? Thanks, Colin.

[bigginger]

Third time of asking - why aren't the quotes working correctly for me, surely somone has an idea?

1st time of answering, and sorry, all I can think is you're doing something wrong.
a

[rayofleamington]

I can think is you're doing something wrong.

Unfortunately not - I can copy and past the same text but get a different result! I guess it's internet gremlins - Somewhere in the world it's after midnight.