BUSTED BLOCK

[bcmc33]

I may be jumping the gun, but it looks like the block is scrap metal.

The chance of me picking-up a 701M block is pretty remote, so the best option is probably a 711M block.

I?ve read a few archive posts and came to the positive conclusion that a 711M block may or may not be a good option.

So, knowing that I?m going over old ground, can I please have some contructive advice from those that have done such a switch.

What exactly do I need to do make the 711M block useable?

Questions that come to mind:

Can I machine the deck to the same height as the 701M and transfer all the other 701M parts?
Can I safely bore the block to suit the 83.25 pistons I?ve just bought?
Should I make the effort and use the 711M as a tall-block?

[gjz30075]

Brian, tell us more about the busted block. Pics? Your machinist tell you it's not fixable?

Good questions, though, moving forward. I'd like to know the answer to #1.

(sorry, minimal contribution here)

Greg Z

[Jason1]

Hi

Have a look at Burton's page:

http://www.burtonpower.com/technical_1/ ... am_8v.aspx

We also offer the water pump housing in two heights to suit standard or Crossflow based engines.
The latter is also a popular route for building a Twink since L-blocks are becoming scarce. In addition, the Crossflow block can be increased up to 1700cc obviously giving a performance increase too. We also stock the special spacing components required, for this conversion.

It may be worth giving them a call, I am sure they can give you a long list of very expensive parts.

I would be interested if it is cheaper to shell out ?1500 on Ebay for a rough Twink or go the crossflow/twink route?

Let you know what you find.

Jason

[bcmc33]

Brian, tell us more about the busted block. Pics? Your machinist tell you it's not fixable?

I said I might be jumping the gun, but I don't really think so.

The block went for rebore to 83.25 and one of the bores was sleeved and one thou undersize for the new pistons, so I agreed to a new sleeve. On removing the sleeve the machinist phoned to say it left a big hole in the block and he did not want to try a new sleeve, even though the previous one had been sound. I will pick the block up on Wednesday morning and take it to the guy who sold me the car as an A1 Top-Dollar specimen. I don't really expect any satisfaction so am looking at the next option.

I would be interested if it is cheaper to shell out ?1500 on Ebay for a rough Twink or go the crossflow/twink route?

Now you know where I'm coming from.

[AussieJohn]

Hi Brian, I had a 85 mil L block with one bore sleeved which subsequently failed; I had it resleeved by a well respected engine builder in Sydney [ Merv Waggot ]; he put in a thicker sleeve and it didn't fail. [ it was through to the water jacket when bored for the thicker sleeve.] cheers, John.

[garyeanderson]

Hard to tell what you have Brian but I think that you are building up this block to the 150 hp range if I remember right. Why don't you put the block part of this project on hold and wait till summer rolls around when Ford is supposed to heve there new Formula Ford block out. This block is being designed so that Both the 1500 height and the 1600 block height can be gotten from the same casting. The earlier block are not. Some folks put the 1600 crank and rods in the 1600 block and use twin cam pistons. To accomplish this the block deck needs machining something like .215 inch 5.5 mm. I guess it works but I wouldn't take that much off. To take a 711 block and mill it down to a 701 deck height you are looking at removing nearly 7/16 of an inch.
The 711 block height is 8.21 inch and the twin cam block is 7.78 inch, .430 inch... think about it, thats a lot of iron to remove.

Gary

[bcmc33]

Yes, well remembered, Gary - the tartget was to be in the tractable 150 bhp region.

However, taking the deck height of the 711M to that of the 701M can be done by lunchtime and the rebore done by dinnertime, I'm rebulding the engine at breakfast time.

But, I'm also aware of the fact that in doing this quick option, I'm missing the opprortunity to have a 1700cc engine.

And I can't wait till summer as I have things arranged from mid March, by which time I expected to have the engine run-in.

[jimj]

I had a, not exactly, similar problem with a paid for event coming up 3 weeks later, so time was short. I bought a short engine from Newark Engines. Google them. I was most satisfied with the product and the price.
Jim

[512BB]

A few things to watch out for when dealing with Newark Engines. Their Ebay name is "Letterslost". They do sell a lot of reconditioned twincam engines on Ebay, both short engines, and with heads, but i have no knowledge of the quality. If you look at their feedback, which is good, they seem to buy a lot of their engines to recon from Ebay, carry out the work, and then put it back up for sale on Ebay.

However, if i was thinking about buying a short motor from them, which i am not, i would certainly ask them as to the type of bearings they had fitted. I say this, as a couple of years ago, i purchased a set of bearings from them, via Ebay, which they stated were suitable for use in a TC. Turned up, they were standard Ford bearings, and not made of VP material, so they wont be going in any TC of mine. Same happened to my good friend Richard {Sprint} recently. An engine shop that he used, and unfortunately, I recomended, supplied him with standard Ford bearings, for his engine rebuild. So just ask the question Brian, caveat emptor!

Good luck with it,

Leslie

[CBUEB1771]

taking the deck height of the 711M to that of the 701M can be done by lunchtime

There is a good chance you will cut into the water jacket by the first coffee break. Check carefully on how far the water jacket goes up on a 711 block before you decide how much to take off the deck.

[bigvalvehead]

Hi Brian
I have built several 1700 engines based on the 711m block and can reccomend them for fast road cars or track days. The extra capacity gives a good flat torque curve and the 1600 rods are just as strong as the twin cam.

How much you have to remove from the block will depend on the piston, if you have pistons with an intruder crown this will affect the C/R which will already be nominally higher due to the increased capacity.

The larger capacity will also allow the use of slightly wilder cams without ill effect

Make sure you extend the bottom of the timing chain tensioner by silver soldering on a brass extension so the plunger makes full contact.
Cheers
Dave Hughes
26-R-9

[rgh0]

Any 1500 block from a very early 116E casting to a late 701m casting can be used as the basis for an 83.5 mm bore engine it does not need to be an L block as all the wall thicknesses are all the same within the casting tolerances. These days you need to find one with as little corrossion as possible of the outside of the bores. Also advisable to thickness test the bores and offset bore to maximise wall thickness. Minimum wall thickness should be 2.5mm .

1600 blocks are more readily available but you cannot machine them down to 1500 height without getting the top deck to thin so need to use at close to the 1600 height which then adds complications to a rebuild but gives you more capacity without having to go to very large bores.

I wuld be wary of sleeving a block with a large hole into the water jacket. It can be done with high strength chrome moly sleeves (very exepnsvie at around $1000 per sleeve for the sleeve alone) or with suitably thicker sleeves but as you up sleeve thickness and bore you end up with less and less metal in the orginal bore casting resulting in loss of block rigidity and it is generally easier to find another block than go down this route

cheers
Rohan

[bcmc33]

There is a good chance you will cut into the water jacket by the first coffee break.

OK, Russ, this was a little tougue-in-cheek comment - I was aware that decking could not safely remove the whole 5mm.

I have built several 1700 engines based on the 711m block and can reccomend them for fast road cars or track days. The extra capacity gives a good flat torque curve and the 1600 rods are just as strong as the twin cam.

Dave,

Did you use the 1600 crank as well as the conrods?

Also, what was the maximum bore you used? I have a set of 83.25 forged pistons that I want to use.

[dusty]

complete engine on ebay.

http://cgi.ebay.co.uk/Lotus-Twin-Cam-SE-Engine-Elan-Cortina-exc-unit_W0QQitemZ290403462190QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item439d652c2e

[bigvalvehead]

Hi Brian
You need to use the 1600 crank whch has a stroke of 77.6mm as opposed to the 72.75 t/c crank
the pistons you have will be fine on almost any block.

If you are stuck for a block I have some that can be used but they have round main caps

Call me tomorrow if you need to chat on 07740 401519
Dave Hughes