The Addiction is Real #3450R

[BDA]

That motor is flat wore out. Kent blocks shouldn't be hard to find but I would investigate sleeving the cylinders. That might be less expensive.

[Rosco5000]

I was really surprised how bad everything is, 35,000 miles only.  It was a virgin block so 60 over bore would clean it up for sure but man was I surprised how bad it was.  I have receipts from the PO on sending the head to California to be rebuilt by a specialist so I hope there aren't any nasty surprises in there.  The bottom end was refreshed locally but more like messed it up.

[BDA]

So the bottom end of a motor that was less than 35,000 miles old was "refreshed"?!

Now it needs to be "refreshed" again!

[jbcollier]

I don't think it's possible to bore an original Lotus block to .060 over.  Sleeving is problematic for the same reason, there just isn't enough meat.  I also thought that Lotus blocks are different from "Kent" blocks.  Kents have ataller deck height?  I know they can be adapted but it's a bit of work.  Hopefully someone who is up to speed on TCs will chime in.

[4129R]

I believe Kent blocks are crossflow blocks, whereas the Lotus L block is a 1500 Ford Cortina pre-crossflow block of different dimensions.

No doubt there is someone who can confirm the exact differences.

Pre-crossflow blocks are not hard to find on this side of the pond, but the postage would be high.

[BDA]

I think there are two Kent blocks and I think the major difference is the deck height. At least that's what I took from the conversation Dave Bean and I had many years ago when we were planning how he was to build my motor. I also understood that the Pinto/Cortina 1600cc used the Kent block and was the block the TC was built on (keeping the camshaft to run the distributor and oil pump). Now that jb, who has surely forgotten more than I know, has questioned that, I did some poking around on the Internet and I never found any direct link between the "Kent block" and the TC. There are several versions of essentially the same block - the general trend apparently was to strengthen it. Could it be that "Kent" has become somewhat of a generic term like "Kleenex"? I've confused myself! 

I suggested sleeving the bore because I was able to do that for an MG block back when I was racing. I'm certainly not a machinist so jb is likely correct. I might still ask my machinist on the off chance that jb is wrong.

[RoddyMac]

There are multiple Kent blocks, they started with the 3 bearing block in the late 50's and progressed to the 5 main that was used up until 2002.  The Twincam blocks were graded 1500 blocks specially cast for Lotus (L cast into them), from what I remember the grades were something like LA / LB etc which should be stamped into the face of the block where the timing cover bolts to.  I also recall that either the LA or LB gets thin when going to 040 over.  I think there were some LAA blocks cast that had much thicker walls (or less core shift) that could be taken out to 060.  There is a section of the Wilkins book that covers this.

There's also this:  http://www.lotuselan.net/forums/lotus-twincam-f39/engine-block-identification-t28613.html

[4129R]

I seem to recall one of my blocks had liners, which made re-boring "different".

[Rosco5000]

From what I have read on the Lotus Elan net it seems that the MkII Lotus blocks were specially cast and no longer graded blocks.  0.060 over bore seems possible in a lot of cases but the consensus was to have the walls ultrasounded so that you knew if you were going to have a problem or not.  I do have a cortina cross flow core but I was hoping to keep that for another project down the road.  However we did contact the seller as he talked a good game that the engine was good when we bought it and he has offered up a crank and block that he has spare so we are going to take him up on. 0.060 over was what Chapman had designed the engine over bore limit to be from my understanding for 1600cc class regulations as the displacement came in at 1593cc right under the 1600 mark so I still have hope that a 0.060 over bore is possible.  We will see once it goes to the machine shop and we get everything spec'd.
R

[Rosco5000]

Here is a link to a reference document on the Lotus Cortina site.  This seems pretty extensive and looks like L blocks of the later years often can go much larger than 0.040 over.  83.5 mm pistons are 0.060 over and some are going to 85 mm pistons with some success. So I will have to dig deeper into what block I have.  I still have some hope for this block being able to rebuild this block with some safety margins.

I have added this link on the blocks as I think this could be a good resource for many.
Cheers,
Ross

http://www.lotus-cortina.com/library/block/blocks.htm

[EuropaTC]

That's a very good summary you've found Ross, thanks for posting.  I didn't realise there were so many options (or pitfalls ?) out there !

Brian

[Rosco5000]

So my saga continues.  Life has been busy and I haven't had time to look at the Europa for awhile.  I moved and have to finish setting up a second home on my family farm.  But there is light at the end of the tunnel.

That being said the machinist doing my work has had his on share of set backs and we are finally getting to the block.  I am excited!!!  Here is a little more information that I have now.  As you all saw that old bottom end was shot!  So I managed to get a 1600cc crank to replace the Lotus one.  My machinist has also confirmed that he can bore cylinders 1-3 40 over but number 4 needs a sleeve.  This block has been sleeved once before and he sees no issue.  Crank was checked no cracks and it looks like -010 though grind and it will be good to go.

Dave Bean got my order the other day.  Ken is very helpful!  He was a great help with my Dad's plus 2 engine and again with this one.  Bean has JE pistons which work with a 1600cc crank and the stock rods so this little beast will be a 1700cc when its all said and done.  The parts should be here next week and on to the next step with the machinist to balance and finish hone the bores.  I'll post pictures as I get things moving!! 

[Rosco5000]

Finally some time to start the first mock up of the Europa engine.

The machine shop was able to sleeve my block and get me bored 0.040 over. 
I balanced my rods and pistons and the machine shop balanced the rotating assembly.
The crank was nitrided so now the 1600cc crank is ready to go.  It fits in the block and just clears the bottom of the cylinder openings.
This is where my question comes for the experienced crowd.
I can easily get a 0.012” feeler gauge between the cylinder openings and the crank web. Also between the block and the rod.  Is this enough clearance? 

[BDA]

I'm not exactly sure what you've got (what is the difference between a 1600 crank and a Lotus crank? Is it a stroker?) but it wouldn't matter because I'm not schooled in the different ways of building Kent motors. I will say that 0.012" seems like a pretty small gap between a crank and a block although in my brief motor building days, I never even thought to make that measurement. I would also say that if your crank bends 0.012", you would have real problems. In fact, I would think you'd have real problems before it bent that much! Consider the gap between the bearing and the journal.

That being said, if I were in your shoes, I would investigate relieving the block a little just on general principles.

[jbcollier]

12 thou should be fine.

Lotus bored a non-crossflow 1500cc block  to make it 1558cc.  The Ford 1600 crossflow used a longer stroke crank.  So, if you fit a Ford 1600 crank into a Lotus block you get a 1700 (1720? Or is that when you use the 1600 block as well).  The next thing to check is that the piston skirts clear the crank webs at bottom dead centre.  I would expect everything is fine if you're following Bean's advice.  Still, check everything!