711M conversion without spacer

PostPost by: lotslow » Thu Mar 01, 2012 10:24 pm

Hi everyone,

I am going to make a conversion to non shortened 711M block in my TC. Would like to avoid the requirement of using a separate spacer.
What parts are necessary and where to get these parts?

Thanks in advance.
Peter
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PostPost by: robertverhey » Fri Mar 02, 2012 12:11 am

From memory, I think steve at ?lan factory sells specially cast taller front covers? Www.elanfactory.com.au
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PostPost by: holywood3645 » Fri Mar 02, 2012 12:31 am

I think Burtons in the UK also supply extended timing chain cover and backplate, chain etc. I went the other route and shortened the block
James
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PostPost by: bcmc33 » Fri Mar 02, 2012 1:35 am

lotslow wrote:Hi everyone,

I am going to make a conversion to non shortened 711M block in my TC. Would like to avoid the requirement of using a separate spacer.
What parts are necessary and where to get these parts?

Thanks in advance.
Peter

Do I understand correctly that you plan not to deck the 711M block?
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PostPost by: garyeanderson » Fri Mar 02, 2012 1:24 pm

47 hits on tall deck
http://www.lotuselan.net/cgi-bin/search ... oom_sort=0

this one talks about full height covers

elan-f15/cassette-water-pump-for-tall-block-711-831-t16957.html

Read them all, it will help make and informed choice

Gary
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PostPost by: vstibbard » Sat Mar 03, 2012 7:05 am

I'd check for clearance with bonnet, as a decked 711m block is often tight, one my s1 I've had to lower engine to get 5mm clearance at driver side front cambox. I'm convinced an undecked block will be an issue requiring expensive mounts to get it even lower and then may be tight.....

Extra capacity never comes cheap...

V
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PostPost by: garyeanderson » Sat Mar 03, 2012 9:24 am

vstibbard wrote:I'd check for clearance with bonnet, as a decked 711m block is often tight, one my s1 I've had to lower engine to get 5mm clearance at driver side front cambox. I'm convinced an undecked block will be an issue requiring expensive mounts to get it even lower and then may be tight.....

Extra capacity never comes cheap...

V


OK so here is My view on this. Its a no brainer to not take advantage of the extra stroke AND the extra height of the tall deck. 45/8221 (engine LP 16301LBA) had the 6 bolt crank 1500 crank when I got it, It was subsequently rebuilt as a 1700 with the 77.62mm stroke FF crankshaft the Ford racing sold for a about $265 back then. I think It had the 1600 rods (4.928 length) with a shortened pin height of 1.313 (memory) JE pistons. This was a sweet engine that ended going into 36/5520 later in its life. I have not had an early block with the rope seal and screw in pickup but have heard that there is a lot of cast iron grinding to get the rotating assembly to clear.

26/4597 was built with a FULL height 711 block and 1600 crankshaft with Datsun 240Z rods (133mm or 5.23xx) and more JE pistons and sits in a tubular Spyder chassis.
elan-photos-f18/the-resurrection-4597-many-photos-and-some-text-t16846.html
This 1700 has a lot more cam and really doesn't like putting around at 20 or 30 mph but it will with some coaxing with the clutch and throat clearing with the right pedal (not quite as bad as I write it but just not a lot of fun to drive slow), this engine has 153 hp and 133 lb/ft. This engine sat on a dyno, not a rolling road and my guess this it about the upper range of torque that a twin cam at 1700 will do. There is a dyno sheet (the pink one) over in the racing section
elan-racing-f12/bsfc-for-racing-twincam-t21422.html
This engine is installed an a gutted S2 that was weighed at the local landfill at 1260 lbs. I didn't have the bonnet on the Elan that day as it was the first day out in it and I wanted to be able to check things at a glance without fumbling around with the bonnet pulls or anything, Just look and see. Add 20 lbs for the bonnet and its a blast to launch. Its been messed around with in the last 15 years so its put on some weight but still is probably under 1300 with a bit of fuel in the tank.

So where am I going with this? Well Mark is building a near duplicate and was asking about clearance in an S2 so I got out the camera that he sent me and got this picture. If you can't get enough clearance (I don't care if it hits, I have molds for the bonnets) then you are just making excuses to not have fun or spend money on what really counts in an Elan and thats the big GRIN that excess power and torque allow you to have. If you just want to show your Elan, don't bother but if you just want to have that giddy look with a big stupid grin, JUST do IT.

bonnet divits.JPG and


I meant to say I didn't build any of these engines, Kenny Duclos did, I just modulate the throttle which in turn works out the muscles on my face. :D
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PostPost by: Mazzini » Sat Mar 03, 2012 11:36 am

vstibbard wrote:I'd check for clearance with bonnet, as a decked 711m block is often tight, one my s1 I've had to lower engine to get 5mm clearance at driver side front cambox. I'm convinced an undecked block will be an issue requiring expensive mounts to get it even lower and then may be tight.....

Extra capacity never comes cheap...

V


Would it be possible to put packing spacers between the body and the chassis to give the 5mm clearance? Assuming that you're putting a new chassis under the car at the same time.

And maybe an extra top layer of thin chassis felt as well.
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PostPost by: bcmc33 » Sat Mar 03, 2012 12:14 pm

Here we go again - off at a tangent. Nobody seems to answer Peter's headline question.

I asked if he was using an un-decked 711M block - in order to say that he would have to use two spacers with standard front end covers, or one spacer with tall block front end covers.

I was then going to go off subject with a supplementary question to ask what pistons were to be used to match the 44.75mm compression height ILO the 39mm TC height.

Regarding clearance with the bonnet - I can only speak for my car that had 3/4" clearance with the 701M block, so the extra 5mm with the 711M decked block was not an issue for me, and I guess an un-decked block would not have been an issue either.

I have to admit that I didn't think to use my 711M block un-decked, but then on reflection, I can only see the disadvantage in needing 'special' pistons. Anyone else have a view on this?
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PostPost by: garyeanderson » Sat Mar 03, 2012 12:39 pm

Mazzini wrote:
vstibbard wrote:I'd check for clearance with bonnet, as a decked 711m block is often tight, one my s1 I've had to lower engine to get 5mm clearance at driver side front cambox. I'm convinced an undecked block will be an issue requiring expensive mounts to get it even lower and then may be tight.....

Extra capacity never comes cheap...

V


Would it be possible to put packing spacers between the body and the chassis to give the 5mm clearance? Assuming that you're putting a new chassis under the car at the same time.

And maybe an extra top layer of thin chassis felt as well.


This probably belongs in the mods sections but I don't care. Chassis felt (as in oil and water adsorbent type),If I were to put this back in ( which I don't) it belongs glued to the fiberglass body tunnel that won't rot, I have two chassis being repaired along the chassis spine as this is being written. Closed cell foam is another thing but I would still stick it to the body tunnel. There is no reason you can't lift the body other that you raise the center of gravity of the Elan. If you can live with that by all means go for it. I would prefer to lower the C of G by dropping the engine by slotting the engine mounts to achieve that. Its your car and you need to do (or not do) what ever it is that you are comfortable with. As far as Brians comments go It work all ways Full height decked .220 inch to make the 1600 crank and rods work with twin cam height pistons. The 1500 height block will also except the 1600 crossflow crankshaft. The cheapest is the heavy decking that Brian has done but I don't like to remove that much cast iron. Thats my opinion and I don't really have any experience with it. If you don't deck the block significantly you can at a future point in time go with an even longer (more money) stroke crank in the range of 82 to 84 mm and get a larger engine, If thats is not in your future, than again do what ever it is you want to, its you money and your Elan.

p.s. Brian you didn't read my posts or follow the links. I don't want to copy and paste each and every re-run

piss-ant wrote:
this one talks about full height covers

elan-f15/cassette-water-pump-for-tall-block-711-831-t16957.html


Gary
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PostPost by: bcmc33 » Sat Mar 03, 2012 1:42 pm

piss-ant wrote:
piss-ant wrote:
this one talks about full height covers

elan-f15/cassette-water-pump-for-tall-block-711-831-t16957.html


Gary

My apologies, Gary - the link does address the question.

So the Burton tall block cover and backplate is the full height of the 711M block - I had wrongly assumed it was to fit the decked block with TC pistons.
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PostPost by: garyeanderson » Sat Mar 03, 2012 2:11 pm

bcmc33 wrote:
piss-ant wrote:
piss-ant wrote:
this one talks about full height covers

elan-f15/cassette-water-pump-for-tall-block-711-831-t16957.html


Gary

My apologies, Gary - the link does address the question.

So the Burton tall block cover and backplate is the full height of the 711M block - I had wrongly assumed it was to fit the decked block with TC pistons.


Brian

You know I try to ask my questions so that I do not need to clarify my question again. The way I read the replies is that the Burton have one that WILL work without milling a stock 8.22 inch tall deck 1600 Kent block. I am sure that the two components will need minimal milling to make the heights (block, backplate, and front cover) the same. If I ever have the money to finish the Alloy KAM block it will have the full height front cover and back plate to hopefully eliminate another "potential" leak that I live with today.

Gary

Hey Peter

are you out there? come back 10-4, little buddy :)
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PostPost by: bcmc33 » Sat Mar 03, 2012 2:38 pm

piss-ant wrote:You know I try to ask my questions so that I do not need to clarify my question again. The way I read the replies is that the Burton have one that WILL work without milling a stock 8.22 inch tall deck 1600 Kent block. I am sure that the two components will need minimal milling to make the heights (block, backplate, and front cover) the same. If I ever have the money to finish the Alloy KAM block it will have the full height front cover and back plate to hopefully eliminate another "potential" leak that I live with today.

Gary,

To satisfy my original curiosity on this thread - what pistons will you be using in the KAM block?
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PostPost by: garyeanderson » Sat Mar 03, 2012 3:14 pm

bcmc33 wrote:
piss-ant wrote:You know I try to ask my questions so that I do not need to clarify my question again. The way I read the replies is that the Burton have one that WILL work without milling a stock 8.22 inch tall deck 1600 Kent block. I am sure that the two components will need minimal milling to make the heights (block, backplate, and front cover) the same. If I ever have the money to finish the Alloy KAM block it will have the full height front cover and back plate to hopefully eliminate another "potential" leak that I live with today.

Gary,

To satisfy my original curiosity on this thread - what pistons will you be using in the KAM block?


The KAM block as purchased is currently linered to 87mm and it came with a set of omega slugs, they are stock Twin Cam pin height and will go unused and a set of JE units will be ordered for a 82 mm crank, longer is possible but my fillings are falling out as it is and I think I will be conservative with the crank. So lets see

208.75mm block height minus 41 mm (1/2 crank) is 167.75 minus stock Cosworth long rods off ~133 = pin height of 34.75

My guess of power and torque would be 185 to 190 hp and 150ish lb/ft from the Twin Cam without turning over 7k
I hope to put this into a type 26 body (Tingles shell)
elan-f14/tingles-production-race-elan-body-t16586.html
with an all up weight of 1150 lbs.
This ought to put a serious grin on my face and turn the shorts brown simultaneously :D
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PostPost by: bigvalvehead » Sat Mar 03, 2012 5:05 pm

Hi Guys
I've run several configurations of engines over the years.

1760cc tall block (711m) with square caps 85mm bore 1600 rods and decked to suit.

1750 ish cc std Lotus block 1600 crank and rods and modified Zetec piston 84.8mm bore( ideal to salvage a +40 Lotus Block.

Currently building a Turbo engine with 84mm stroke N/J crank 132mm rods Cosworth forged pistons with comp height of 29mm Pistons currently 5mm down bore which may be adjusted to acheive 7.5:1 CR as the boost pressure I intend to run will be approx 20psi.

The extra torque from the 1st two engines is great and with rally profile cams is still fine in a light car like an Elan.

I've always made spacers and secured them to the water pump case with c/s screws prior to machining the deck of the block as per David Vizard in Tuning Twincam book. Never had a problem even on the 1700 turbo engine built 30 years ago.
Dave
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