Used Engine Block Options

[S2Jay]

Well, many thanks to all who have offered insight into this process.

I have heard of the new Blocks & the Heads also. I don’t recall pricing for the blocks, but I am guessing that they are out of my budget for this project [with too many other projects waiting for the same funds – my best excuse].
I have seen pricing for the heads & I am “positive” I am not in the market for those [unless I want to start living in one of my cars, which is where the wf would have me].

[I am reminded of an old W.C. Fields movie. [Apologies to any who are not familiar w/W.C. – old b/w films from the 1930s.]
He played a shopkeeper of sorts, behind a large counter. Perhaps a coffee shop & maybe “sundries”. Whatever.
At any rate, a tourist walks in, quickly, apparently in a rush, holding a $100 bill, and asks, “Do you have change for a hundred?”
As Fields reaches for the bill, as if to take it to make change, he begins to mumble on about “No, no I don’t” As he examines the bill, holds it up to the light, etc, he continues, “I’ve never seen one of these.”
As he hands the bill back to the tourist, he adds, “Thanks for asking, though.” I didn’t get it at first, then I realized that Fields was flattered that the man even thought that he could possibly have change for a Hundred - this was the depression-era 30s].
That is about how close I am to the market for a new Block. But, “Thanks for asking”.
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With the confirmation from this panel that the o/s jackshaft bore could be an issue, I am now requesting pricing & details on the other 120E / 2731, unbored block.

“Worst case” scenario may be just using the original block. I have already realized that I am not likely to put all that many miles on it. Actually, I have been less concerned about the miles than with the possibility that I could do some permanent damage.
Maybe better to use that part of the budget to try to find a used T/C head to port. I don’t really want to port that head, especially if I need to do it myself. This would “save” the orig head in uncut/un-ported form.
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[nmauduit]

The price of new blocks is relatively reasonable nowadays (there are several suppliers), then come taxes, shipping, customs... e.g. at for 1500 quids (no affiliations, just an item on my wish list)

https://qedmotorsport.co.uk/product/701m-l-ford-cylinder-block/

new 701 block 40000psi

you're welcome.

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as for rejuvenating / rebuilding the original block, if it suits your need (no need for ultimate performance, gentlemanly use during the occasionnal track days among friends...), this may make sense too and would increase the authenticity of the experience, then you can always build a mix and match beefier engine on your spare time (then remember the chassis/suspensions will need upgrading for adequate match)

[Craven]

Not sure of the designation 120E/2731, two different block casting ? check to see if the 2731 block has been previously used with a Lotus crankshaft as an unmodified block will not accommodate the larger balance weights of the Lotus crank. Small modification needed but extra cost.
A doable wall thickness check is via the rear water core plug this is usually where the thinnest wall is found.
FWIW.

[rgh0]

A doable wall thickness check is via the rear water core plug this is usually where the thinnest wall is found.
FWIW.

I have ultrasonically surveyed many blocks and the thinnest wall sections vary at random from bore to bore and also orientation in the bore. Checking just a limited area through the rear core plug will give you just one data point. If the wall on the opposite side is thick then a small offset in the rebore will be possible. When the blocks were tested for Lotus for the LBA / LBB stamping on the front face they did a couple of calliper checks through the core plugs but this was far from being conclusive

You really need to do a full ultrasonic survey. I check each bore at 90 degree intervals ( front, rear and each side) along the entire bore length. I then check between these going each way from the lowest reading to see if it gets significantly thinner. You generally find a simple centre line offset between the casting outer diameter and the bore diameter i.e. both are round and the offset is caused by a bore pattern shift in the casting process. I don't see any systematic shift in the castings just random movement in centreline and also random variation in bore casting OD, that does not relate to T number or L block designation despite the myths to the contrary.

The few new Ford motorsport blocks I have measured are much better cast with less centreline shift and less variation in bore casting OD. It means they all will go to 83.5 mm based on my sample but they will not go beyond that. With older blocks you find a some that will go to 84mm and a few to 85mm with suitable offset boring


The other biggest issue with old blocks is corrosion at the level of the bottom of the water jacket thinning the wall.

cheers
Rohan

[Craven]

If the OP is prepared to pay for a full survey of the block, before purchase, fine. Also the 2731 block has push in oil pipes which may be a consideration.

[2cams70]

You'd have to have bad luck to not be able to bore the 2731E casting to 83.5mm given it's currently at 82mm.
If you aren't a rev head (frequent operation over 6,000 RPM) it will likely be fine with the round main caps too. I'd change the caps to square types but I'm a rev head. The original engine unless it was a 701M block or modified will have round main caps in any case.

Changing to a press in type pickup is only a small issue.

[Craven]

OP say’s S2 = 4bolt bottom end, press in oil pipes = 6 bolt sump ?? different baffle plate position.
6 bolt sump = £££££ or $$$$$

[2cams70]

Aah yes - lip seal sump required with 2731 block. It’s just an old Mk2 Cortina sump. Produced in the millions - where are they all?? Six bolt crank required too so it’s starting to look expensive any way you look at it.

[S2Jay]

Actually, I have been collecting 6-bolt/Stroker crank conversion parts, and I think that I have most of the parts needed, based on a list posted by Rohan previously, including the 6-bolt Crank & Square Shoulder Main Caps, Lip Seal Pan, Backplate & Flywheel. Also a set of 125 E Rods. So, it sounds like that should help.

[2cams70]

I hate stroker engines personally. Personal taste. Be prepared for a 5 speed gearbox or diff ratio change also in that case.

[rgh0]

Aah yes - lip seal sump required with 2731 block. It’s just an old Mk2 Cortina sump. Produced in the millions - where are they all?? Six bolt crank required too so it’s starting to look expensive any way you look at it.

A few of them are sitting in my garage No one in Australia has any now as they were all scrapped along with the old Cortina engines about 15 years ago.

cheers
Rohan