Lotus Elan and Lotus Elan Plus 2 Forums

Hi guys - thanks for all the help and coaching so far. Looking at engine specifications online it looks like the +2's had somewhat more powerful engines than the earlier convertibles (DHC if saying "convertibles" will get me in trouble here - grin). Are the engines physically the same except for displacement? Everything bolt up the same? IF in fact the +2's had more grunt do people retrofit those into the open (in case writing DHC gets me in trouble here).

My experience with Alfa GT's where people alternate between originality vs later 2.0 SPICA engines has me wondering about how you all think about it.

Thanks!

All the engines had the same capacity 1558cc.

There were 3 specification of engine tune. "Standard", "S/E" and "Sprint or Big Valve". The differences were mainly in the cam shafts used, carb choke sizes and exhaust manifold style. The Big Valve head also has slightly larger inlet ports and higher compression ratio.

The S/E tune was offered as an option from early on in the Elan production along with the Standard tune engine. All Plus 2 I believe came with the S/E tune engine from the beginning of production. Around 1970 the Big Valve tune engine was introduced in the Plus2 130 and the Elan Sprint and it was the only engine option from then to the end of production.

The other variation was use of the Stromberg head in US cars from around 1968 and on European cars in the 1969 / 70 period. Many of these appear to have used the D type cam as used in the later Sprint.

cheers
Rohan

And what Rohan implied but didn't explicitly state is that any of those engines will fit in any of the Elans, whether 2-seater or 2+2 seater.

But the stromberg carbed engines will need a bonnet with a bulge in it.

I was going to post a question on here today but it is suitably close to this thread I might as well ask here.

What sort of performance can be achieved from a 2 seater elan?

I am embarking on a 26r replica for the road, light weight but not the full on race engine.

What sort of 0-60 time can be achieved? (I know 0-60 is not everything, but it is a useful theoretical comparison)

Fantastic information guys, very much appreciate the coaching.

Any special fitting challenges that a "tall block" presents?

tdskip wrote:Fantastic information guys, very much appreciate the coaching.

Any special fitting challenges that a "tall block" presents?

The Wiki has not yet been released by our webmaster but some articles etc can already be read. This one covers rebuilding engines, includine using a tall block.
http://www.lotuselan.net/wiki/Torquing_ ... am_Rebuild


This bit covers the fitting into the car:

If an engine is rebuilt using a taller 1600 block then engine mounts and bonnet clearance will need to be checked.

Due to the additional 1/2" on the 1600 Crossflow block exhaust side mounting bosses, the original mounts will not work as they will be spaced out the additional 1/2". This additional 1/2" can be machined down off of the block mounting bosses, certainly a nice & tidy solution. If this is not possible the original engine mounts can be modified or replacements made.

The bonnet clearance is not a problem for Europas, Escorts and Cortinas. However for Elans and Sevens any additional engine height can lead to the cam cover fouling the bonnet. If this is the case then you may have to manufacture some new engine mounts. There have been articles written where "spacing" the body off of the chassis has been suggested. This does seem to be a rather crude solution, and would no doubt lead to body/chassis problems latter on. For this reason new or modified engine mounts seem far more sensible at what must surely be no additional work in comparison.

TDSKIP and Barty, hmmm, odd names!

Anyway, Rohan and Bill are right on the money. As for the tall block, you may have clearance issues due to the extra height, and there will have to be a spacer plate installed at the front cover/waterpump assembly. Just another place for a possible leak.

As for the 0-60 time, that is one of my favorite sprints! I mean rarely can you find out what top end is, but 0-60 can be tested on numerous local roads and usually next to some other unsuspecting vehicle!!!

Years ago (35), it was fairly easy to attain a 6 second time. That's not quick enough for me. The factors other than weight that can affect the 0-60 times, are tire, gear ratio, limit slip, etc. Let's start with tires. The widest, stickiest, softess compound will usually give you the best adhesion. Getting it to fit within the confines of the wheel well will be the challenge. A shorter gear will give you av mush better 0-60. Use say a 4:11 versus a 3:55 or a 3:77 will give you a much better 0-60, albeit with a much busier highway cruising rpm. The limited slip will also help greatly. Two wheels propelling you is always better than one.

The last part you had better pay head to is the inner and outer stub axles. 1) Don't try to get great 0-60 times using the original donuts. Convert to CV joints or sliding spline axles. Once you start accelerating quicker, the cast stub axles will break. These should be replaced with forged units.

Oh, and don't forget to upgrade the diff mounts and the diff case.

Mine is equipped with a diff brace, Tony Thompson diff mounts, forged inner stub axles, CV joint axles, forged outer stub axles, alloy wheels, a limited slip, a 3:77 gear but with a 3:43 first gear in the five speed trans. I'm looking forward to some healthy 0-60 times with 157 HP available. I'm hoping the tires will stay the weak link!!!

Good luck and Good Hunting!!!

Frank

Hi Frank, thanks for the additional info.

How much taller is the tall block? Fit issue in the roadster (in case convertible, DHC etc... the wrong way to refer to them - grin) only or +2 as well?

Sound like you aren't afraid to use yours in "anger", fantastic.

The tall block is roughly 12 mm taller but it depends how you build it as one version is decked significantly so it is more like around 6 mm taller. The Plus 2 is generally tighter on clearance at the front of of the engine to the bonnet than the Elan but you can normally drop the engine mounts by slotting the holes to get sufficient clearance.

You can also build a long stroke big capacity engine on the standard 1500 block by using low compression height pistons if you want.

cheers
Rohan

tdskip wrote: Are the engines physically the same except for displacement? Everything bolt up the same?

All of the engines are basically the same, but there are 2 distinct differences throughout production.
Bottom end:
MK1 engines - 4 bolt crank, Rope seal. Pre 03/67
Mk2 engines Six bolt crank Lip seal Post 03/67

Top End
Weber/Dellorto head
Stromberg head

Thank you for the additional information and details, very much appreciated.

What were the gearbox changes during production?

Did they follow the Ford ?volutions of the period like single and 3 rail selectors, aluminium tailshaft with remote extension etc or did they all use the Anglia casings?

The same basic 2000E style gearbox with the 3 rail change with direct coupled lever ( no remote change) and a cast iron tail shaft housing and bell housing was used in all 4 speed elans and plus 2. The actual details of the castings changed over the years as Ford changed their castings but they are all interchangeable. The gear ratios changed with the close versus semi close ratio boxes and the details of the gear assembly and synchros onto the output shaft changed as Ford changed their internals details, which means you cant change individual internal components freely. Once assembled functionally they all bolt up into the car in the same ways the different engine block versions all bolt up.

cheers
Rohan

Just to follow up Rohan's comments about interchangeability of the 3 rail gearboxes, it should be noted that the earlier 4 bolt crank engine requires a different gearbox spigot bearing in the end of the crank compared to the later 6 bolt crank.
The 4 bolt crank has an Oilite bronze bearing OD 40mm ID 15mm or 17mm. The later 2000E gearbox has a 15mm spigot and the earlier close ratio or ultra close gearboxes have a 17mm spigot.
The 6 bolt crank has a needle roller bearing OD 21 mm ID 15mm. I'm not sure what happens if you want to fit an early close ratio box with a 17mm spigot to this crank. I expect someone will be along to answer? Machine an Oilite from 40mm to 21mm?
Malcolm

? the gearbox fits into the clutch doesnt it? not directly to the engine crank?

So it may be a different flywheel needed, to accept a later clutch?