New Engine Rebuild......

[simonbuk]

So some discussion took place about an engine i had rebuilt and an old engine that looked a bit er.....kaput.

Things got a little lost as it came under a thread about some odd CV boot grease i encounted .

Anyhow, i was told to check the main bearing shells to see if they have two holes in them as the turbo model should. I have just removed a main bearing cap only to find that the bottom shell is plain (as it should be) and the upper shell is the one that should have the holes in it. This obviously led to the rest being removed so i could lift the crank up to see the upper shells.
Only one hole in the shell (with a groove in it). Whilst putting them back loosely one was a bit fiddly and realised that that was the one with the thrust washer in it - i've scored it a little.

Somebody suggested drilling the extra in the shell but i'm a bit weary of that . Shall i just take it to a machine shop and let them do it ?

I want to learn and understand though -

I've bought some Plastigauge Type PL-A to measure 0.025 - 0.175mm - right stuff ?

I found the marking on the block that says 11112, so i think that refers to journals 1-5 ?

I haven't yet found a marking on the crank which there should be i believe........

If i'm to find any of the elusive original shells from Lotus - i've got to cross reference the number of the journal with the crank web mark with the plastigauge results using the table on page 55 of section EC Lotus Service notes ?!..............and breath.............

[TorqueHorse]

I've bought some Plastigauge Type PL-A to measure 0.025 - 0.175mm - right stuff ?

Maybe that is a multipack of different sizes? I used the green one, SPG-1

I found the marking on the block that says 11112, so i think that refers to journals 1-5 ?

Yes, that is the main bearing bore diameter reference # for the journals

I haven't yet found a marking on the crank which there should be i believe........

It's easeir to see when the crank is clean. Here is a photo of mine (the little "- -" marks chiseled in)

image.jpg

If i'm to find any of the elusive original shells from Lotus - i've got to cross reference the number of the journal with the crank web mark with the plastigauge results using the table on page 55 of section EC Lotus Service notes ?!..............and breath.............

Almost...The plastigage only measures the gap, not from where the gap came from, i.e. did the main crank wear, or the bearings. In a perfect world you take the crank to a machine shop and they "mic" it using a micrometer to determine exactly what the dimensions are for each journal and then, cross referencing with those block numbers, you select your bearings based on that. BUT for the at home garage mechanic, based on what most people have reported here over the years, the crank rarely wears, so we will assume that any gap you find is from bearings wearing.
So, start with the plastigage on your existing bearings and crank and see if any oil clearances are out of spec. For the ones that are out of spec then you can look at the chart using those main bearing bore block numbers and the marks on the crank for the respective journals, to see which color bearing you need for that journal. The "good" news is that for your main block bore range of 1's and 2's all of the bearings that are applicable for that range (Blue, Black, Brown), are still available at SJ and Classic Team Lotus, etc. But at a cost. (BTW, I have an almost new Blue one that you can have if you just cover the postage. The first time I did my engine, I misread that table and got the wrong one.) So take a look, see what you need and then you can decide if you want to drill holes in the ones you have, try and buy some new ones, or something in-between.