Engine backplate

Post by **bmcecosse** » Sun Nov 23, 2008 7:01 pm

Was building up my 1275 engine today - and the 1098 backplate fitted fine after I had opened up the hole around the crankseal. The oil-pump cover fits on fine - no need to do anything. This is with a 'steel backed' oil pump - the best! I compared the 1098 and Marina backplates - the Marina has a slightly larger oil pump cover - but it's on exactly the same centre as the 1098 cover. However what I did find is that the top dowel in the 1275 engine is slightly larger diameter (.371") than the 1098 dowel - and so I had to open out the matching hole in the backplate slightly - and the gearbox in turn will need that hole opened up too.
Question 1 - is it ok to use the little needle roller bearing that's in the Marina crankshaft tail ? It's a snug fit for the gearbox input shaft - but the box does fit on. In fact I couldn't get a stainless bar I was using as a gauge to go in to the roller bearing - and then I realised it was actually .503" - and the gearbox shaft (on one of my spare boxes) is only .495" - I expect it was .500 at one time !
Question 2 - has anyone checked the run-out of the 1098 flywheel after drilling and fitting to the Marina crankshaft ? Since the crank doesn't have the raised centre section to align the flywheel - it's only located by one snug dowel and the six bolts. Doesn't help that just at the moment I seem to have 'mislaid' the flywheel bolts - but using one bolt I did find shows an intial run-out of about 10 thou. I suspect i will need to fit all 6 bolts (when they come out from hiding) - and then carefully set it all up - and then drill and fit the second dowel. Can I ask what others have done ??

Post by **PSL184** » Sun Nov 23, 2008 7:08 pm

I only used one dowel to locate and then centred the flywheel before tightening the 6 bolts up. I can't see it going anywhere and didn't see the need for drilling for the other dowel... As far as the backplate is concerned, I had to open up the hole for the rear crank bearing and also modify the opening for the oil pump cover which actually, in effect, would have meant it slightly off centre. The oil pump needed a slight file to get the cover on but nothing major. I also had to modify the front plate by drilling a hole for the timing chain tensioner to sit in at its pivot point. This was with 1098 parts on a Marina 1275 block.

Post by **bmcecosse** » Sun Nov 23, 2008 7:59 pm

Thanks for that - but did you measure the flywheel run-out ? Although 10 thou is not much - at 8000 rpm it may mean something! I'm surprised you had to worry about the oil pump cover - I suppose it depends which pump. The steel back pump is recommended as giving best delivery - and fortunately it fits in nicely! What about the dowel at the top of the engine - did you just 'lose' it - or did you open out the holes ?

Post by **PSL184** » Sun Nov 23, 2008 9:22 pm

I haven't got as far as offering the gearbox up yet Roy, but I'm thinking I may well open the holes up to take the top dowel. I haven't measured the run out on the flywheel all the way around but I did it at 4 or 5 points around the perimeter in order to centralise it. I don't think 10 thou will give any worries though....?

Post by **bmcecosse** » Sun Nov 23, 2008 10:35 pm

Just not sure how good it should be - or was before! I've set up a little wire pointer on the rim - and I can see about 10 thou gap one side and just a 'touch' on the other. But until these wretched bolts appear - I'm a bit stuck! They are not lost - just put somewhere safe many moons ago!!

Post by **PSL184** » Sun Nov 23, 2008 10:42 pm

I've got loads of stuff stored safely that I'll never find again !!!

Post by **bmcecosse** » Sun Nov 23, 2008 10:48 pm

Aye - but these bolts are really annoying me. There should be 6 from the Marina flywheel - and 4 from the Minor flywheel. So far - none to be found - grrrrr.

Post by **Matt** » Mon Nov 24, 2008 8:21 am

8000rpm from a marina engine? I suspect you are being optomistic ;)

Post by **bmcecosse** » Mon Nov 24, 2008 9:12 pm

I know it will - it must!

Post by **PSL184** » Tue Nov 25, 2008 8:19 am

Right then... Engine and gearbox now mated and no need (for me) to increase any dowel sizes. Apart from having to very carefully slide the output shaft into the engine without loosing the clips off the clutch assy, all went quite well. Spent about an hour or so piping up the cooling system until I was happy with the pipe run and had to fiddle the run of the fuel pipes (using lift pump) to get enough room away from the manifold (LCB). Exhaust system is sitting very close to the floor at the moment - particularly I'm not happy with clearance to the crossmember so this will need more adjusting. The only other problem I had was that I could not get oil pressure light and oil gauge connected due to lack of room for T piece, sender and pipe fitting (fouls on starter motor), so I've only got gauge connected at the moment. I used the 1275 timing cover to retain the original 1275 adjuster and have no issues with this (except for modifying 1098 front plate to take adjuster). I also retained the 1098 heater tap and slightly modified the battery box to give clearance. Last 2 alterations were to fit longer choke and accelerator cables as the originals didn't reach. Now I have an ugly modern choke control knob in the car which I will address later!. Going for the first start up tonight so hopefully, fingers crossed ;-)

Post by **bmcecosse** » Tue Nov 25, 2008 9:29 am

Well done ! Seems odd only my engine would have the slightly larger top dowel - is that dowel present on your engine (between the two top securing bolts) - or has it fallen out ?? Be sure to raise oil pressure with plugs out before going for a 'start' !

Post by **MartinB** » Tue Nov 25, 2008 5:07 pm

10 thou seems a large run out of the flywheel to me. Is the crank tail running true? Would have thought 2 to 3 thou was more acceptable.

Was the crank/flywheel/clutch assembly balanced before you built it up?

8000 rpm with that run out seems a bit dodgy to me!

Martin

Post by **PSL184** » Tue Nov 25, 2008 5:22 pm

Roy, yes, dowel is present but slipped in OK. Engine has started OK and exhaust sounds just right for what I want... Sporty, but not too loud. Not been for a drive yet though as its refusing to draw any fuel from the tank (I'm running off a fuel can) and the starter motor needs to come off again to fit a spacer or machine the flange due to it (just) catching the flywheel. Maybe I should have checked the run out too after reading Martin's comments but its a bit late now

Post by **bigginger** » Tue Nov 25, 2008 8:02 pm

????? Dowel IS usually bigger on the 1275

linearaudio · Post by **linearaudio** » Tue Nov 25, 2008 8:10 pm

bmcecosse wrote:Aye - but these bolts are really annoying me. There should be 6 from the Marina flywheel - and 4 from the Minor flywheel. So far - none to be found - grrrrr.

They're right in front of you on the bench. You've been seeing them so much over the last X months that you are blind to them. At least that's what I usually find!

Post by **bmcecosse** » Tue Nov 25, 2008 8:40 pm

Bolts - well - unfortunately they are not 'right in front of me' - but I know I put them somewhere safe!! Run out - i've not checked the crank tail for run-out - that's a good idea. I've not settled this yet - the 10 thou run is just a first measure taken with only 1 dowel and one bolt in place! Of course it was all beautifully balanced - i'm sure Rover would do that - wouldn't they ??
Dowel - maybe your box had already been drilled out to take a larger dowel PSL - but then I had to run a drill through the 1098 backplate to get it over the top dowel. Strangely the bottom dowel seems to be same on both engines - so goodness knows why they decided to change the size of the top one !

Post by **PSL184** » Tue Nov 25, 2008 8:58 pm

Not sure either Roy and I don't have any history of my gearbox or engine to know what had been done to them in the past... Definately didn't have to modify backplate for the dowel either (just oil pump and rear bearing/seal) Makes all these mods more interesting I guess

Just proves that there is always more than one answer

Post by **bmcecosse** » Tue Nov 25, 2008 9:06 pm

Indeed - anyway - well done getting it running! I've no idea when I will fit mine - it's just on the bench at present, and this is the 'mild' engine with MG cam and probably a standard large valve head. Then I will start on the second engine - for which I have a 544 cam and a modified large valve head standing by. However - I need to fit pistons to rods for that one - may need some Dutch Courage for that job!
Has anyone here done that successfully ? There used to be a video going the rounds of AC Dodd doing it - but I lost the link when my hard drive was wiped.

Post by **bigginger** » Tue Nov 25, 2008 9:22 pm

bmcecosse wrote:
Dowel - maybe your box had already been drilled out to take a larger dowel PSL - but then I had to run a drill through the 1098 backplate to get it over the top dowel. !

Like the 3 I've converted, then. I'd always assumed they were all like that

Post by **bmcecosse** » Tue Nov 25, 2008 9:51 pm

I assume so too Andrew!