Lotus Elan

My first engine rebuild

PostPost by: Chancer » Sat Dec 02, 2017 1:42 pm

Ah the pleasures of paying a professional to do work for you! the gift that keeps on giving :D

I say this jokingly but with a lot of guilt, my best friend gave me his X:flow engine to rebuild and modify as "you know what you are doing" and indeed I did but everyone makes a mistake at some time.

During a rolling road session I could see the crank pulley moving and told him i would like to pull the engine as a precaution but if it was what I thought it was then it was going to need a new crank.

It was what I thought it was :( muppet me had fitted the thrust washer the wrong way round, no excuses, i knew there was a correct orientation and the results of getting it wrong.
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PostPost by: promotor » Sat Dec 02, 2017 2:46 pm

Concrete-crusher wrote:Thanks for the advice , which way round should the thrust washers be fitted. Should the two grooves face the crank surface or the block.?

Some web sites say they face the bearing surface which I call the crank , but page 115 of miles book has a picture showing the grooves facing the block.

The ones I took off , had the grooves facing the crank on the front and the grooves are worn off the rear.

Steve


The grooves are oiling/lubrication grooves to allow oil to pass between the crank and thrust washer - this means the grooves face the crank. The numbers/part number/size etc are stamped on the non-contact face so that these can still be read - if they were on the "wear face" you wouldn't be able to read them after much use.

If the grooves are worn off the rear bearing then it sounds like it has been in the wrong way - I would check your crank for wear as this is likely to have been affected to some extent.
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PostPost by: Concrete-crusher » Sat Dec 09, 2017 1:59 pm

I still need to have the crank inspected by an expert , the block cylinders were worn by 005 thou so are being rebored to 020 thou. that means new pistons which I now have from Burton.

turning my attention to the con rods the 6 gram difference on my earlier post is on con rod number 1 , a closer look and its an even bigger difference once they are split apart. I only have 3 rods with me , the 4th is at the engineers

can these be balanced out or am I looking at new rods. I keep thinking the whole starting point was to get a smoother running engine as it was lumpy to say the least.

the weights are:

1 , 2 , 3
rod 384 , 381 , 381

cap 260 , 269 , 265

total 644 , 650 , 647

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PostPost by: nmauduit » Sat Dec 09, 2017 2:35 pm

you can balance your rods, then your pistons as well when you get them : it should be easy enough to achieve better than 1g with the modern scales one can get nowadays, just make sure you take material out from areas that are not critical, and slow when you get close to the target weight.
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PostPost by: StressCraxx » Sat Dec 09, 2017 5:23 pm

As said earlier, balancing your rods is good practice.
Have you talked with your machine shop about reconditioning your rods? It's not expensive. They will inspect them, including checking the center to center length and resizing to spec if needed. Then they will balance the big ends and the small ends. Purchase the ARP or Cosworth rod bolts. They are the same cost or less than the Ford bolts and you can reuse them. The Ford rod bolts are not reusable.

Inspect the crank, crack check, inspect journals for size, taper, etc. Grind and polish if needed. Have the crank balanced. Then index the flywheel to the crank and balance the flywheel and the clutch. Make sure the flywheel mounting face is clean and free of burrs. Mount the flywheel on the crank and check the flywheel for axial runout. I found mine had more than 0.006" axial runout making it wobble! A good balance shop can do this for very reasonable cost.
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PostPost by: Concrete-crusher » Sat Dec 09, 2017 6:41 pm

I think I'm convinced to let the machine shop inspect and balance them as required.

I was going to fit a new waterpump today but found the adapter ring damaged , so that's on hold until I get another one. I do have a few worn threads in the front cover to sump also on the rear oil seal to sump.

There 1/4 inch unc as far as I know , are these simple to replace with helicoils and are the ebay kits any good.

Thanks steve
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PostPost by: MarkDa » Sat Dec 09, 2017 6:51 pm

Yes 1/4 UNC.
Helicoil should do the trick.
There's always an element of getting what you pay for with tools.
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PostPost by: 2cams70 » Sun Dec 10, 2017 12:03 am

Don't try and balance the rods yourself as the small and big ends have to be balanced independently. Make sure you have the machine shop fit new small end bushes too, or at least have them checked for size after you purchase pistons. The clearances between the piston pin and the small end bush are amongst the smallest in the whole engine and are quite critical. The Ford big end bolts are fine for a standard engine used at standard RPM's and can be re-used if they haven't been overtightened in the past but better to use new ARP bolts if you can. Give the new bolts to the machine shop so he can check the big end sizing using these rather than the original ones.
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PostPost by: Concrete-crusher » Sat Dec 23, 2017 6:54 pm

I have got the block back and I thought first job paint it. After reading previous posts I decided to clean it first with cellulose thinners under pressure using a gun , great job of degreasing the surface but it has left stains on the freshly honed bores. But I'm told not to worry about it. I have new omega pistons and the rods , crank and flywheel have all been balanced.
img_0444.jpg and


Turning my attention to the thrust washers , the rear was quite worn and the case has signs of a previous repair in this area , my first question are the washers just a very loose fit held in place by the crank ? , and second looking at the edges where the rear washer sits it's quite burred , should I gently grind this down smooth ?
img_0441.jpg and


Thanks Steve
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PostPost by: rgh0 » Sat Dec 23, 2017 9:29 pm

Put some WD40 on the bores to stop them rusting while you do the assembly.

The thrust bearings are held in place buy the centre main cap. Make sure you set the crank end float within specification buy using selected thickness thrust bearings, they are available in various oversizes. Remove any burrs so everything fits fiat and square.

cheers
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PostPost by: alan.barker » Sun Dec 24, 2017 10:44 am

Sorry if it's already been said but I suggest you fit new core plugs in the block also. For this i use Loctite 648 to be sure they don't leak. :shock:
Alan
ps while the core plugs are out get a Karcher and wash out inside the block.
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PostPost by: Concrete-crusher » Sun Dec 24, 2017 4:22 pm

Hi Alan , I should have added that I have changed the core plugs and did flush the block.

I spent a few hours on the head and had calculated new shims all around the 150 thou mark compared to the 60 thou they were previously. I bolted down the head and fitted the new shims , I'm about 2 or 3 thou out on each one.

I guess it's the error on multiple feeler blades with the larger gaps. Anyway I,m getting much closer.

I have also bought new pistons , they are the omega brand sold by qed and burton.

There,s no instructions on fitting the rings , I assume they are packed in the correct order 1st is thinner , 2nd looks slightly thicker than 1st then the oil control ring.

Can anyone tell me if you take the spring centre out of the oil control ring and fit that first followed by the ring , or do you open them both together

Cheers Steve
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PostPost by: KevJ+2 » Sun Dec 24, 2017 4:38 pm

I also think the rings should have TOP written on their top edge.
I have put in oil rings with the centre 'spring' both in and out, but probably better complete.
Don't forget to stagger the ring gaps before final fitting.

Kev.
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PostPost by: Craven » Sun Dec 24, 2017 5:33 pm

If you haven?t fitted the rings yet try a ring in the bore and check the ring gap ~ 0.009 make sure the ring is square to bore.
I fit the inner coil first on oil control ring.
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PostPost by: Concrete-crusher » Wed Dec 27, 2017 11:43 pm

So after turkey leftovers it's off to the garage to start putting my engine back together

The first job was to refit the jack shaft , and as the manual suggests measure the gap between the thrust plate and jackshaft , its 005 thou , the manual says 025 thou so I'm not sure what to do if anything. There were no problems with the thrust plate or jack shaft. I'm tempted to just leave it.

The second job was to refit the crank and measure the end float. This was after smoothing down the rough edge shown in the previous post.

My end float is 009 thou , the manual says 003 -011 so it's in spec , but high , I'm thinking of changing one of the thrust washers for a 005 thou over size. Does this sound correct , and is it better to change the rear washer ?

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