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DiDueColpi
Fred Key
West coast - Canada
(1331 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

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I think I found a unicorn 2.0
Posted by: DiDueColpi
Date: December 02, 2021 09:52PM

Been cleaning up after the floods and found a crank that I had squirrelled away and forgot about.
It's an NOS 2.2 litre Lotus crank.
It just happens to fit into a RV8 block like it was made for it. Sort of.
There's enough material and strength to machine it for narrowed v8 rods.
So the RV8, Lotus 16V, flat plane, Lover engine just got a major injection of renewed interest. (and Art thought it was dead :) )

thumbnail_IMG_1171.jpg

Live like you mean it.
Fred


joe_padavano
Joseph Padavano
Northern Virginia
(151 posts)

Registered:
02/15/2010 03:49PM

Main British Car:
1962 F-85 Deluxe wagon 215 Olds

Re: I think I found a unicorn 2.0
Posted by: joe_padavano
Date: December 04, 2021 10:39AM

Good discussion of why this might not be the best idea.

[www.enginelabs.com]



Edited 1 time(s). Last edit at 12/04/2021 10:40AM by joe_padavano.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6198 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: I think I found a unicorn 2.0
Posted by: BlownMGB-V8
Date: December 04, 2021 11:06AM

So it needs to be a long rod engine with at least a 2:1 rod ratio. What is the stroke of that crank?

Jim


88v8
Ivor Duarte
Gloucestershire UK
(979 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: I think I found a unicorn 2.0
Posted by: 88v8
Date: December 05, 2021 05:10AM

Good discussion of why this might not be the best idea

It could be a good idea if you want to incorporate a massage seat.

Ivor


DiDueColpi
Fred Key
West coast - Canada
(1331 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: I think I found a unicorn 2.0
Posted by: DiDueColpi
Date: December 06, 2021 02:42PM

I have 2 cranks to choose from Jim. The short one (2L) is 2.726" stroke and the 2.2L is 3.000" stroke.
I own a 1979 308 GTS and a customer has a SCG 335 LS flat plane v8. Neither one has an objectionable vibration.
I agree that a long rod engine would be best so the 2L crank would be used if this proceeds.
This all started because I didn't want to spend the money on 4 custom cams. That rational has become silly.
Now its all about the sound.....and someone said it couldn't be done.

Cheers
Fred


minorv8
Jukka Harkola

(245 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: I think I found a unicorn 2.0
Posted by: minorv8
Date: December 07, 2021 01:15AM

What is the width of the rod journal i.e. how much you need to narrow the rods ?


turbodave
dave cox

(98 posts)

Registered:
04/30/2018 03:00PM

Main British Car:
SD1

Re: I think I found a unicorn 2.0
Posted by: turbodave
Date: December 07, 2021 07:37AM

Interestingly TVR built a supercharged 2.0 V8 for the Italian market (to get around the engine capacity compliance of the time). Was de-stroked to 2 litres. Not much info about it, and they didn't sell many - not surprisingly.



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6198 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: I think I found a unicorn 2.0
Posted by: BlownMGB-V8
Date: December 07, 2021 11:53AM

The 3" stroke would only require a 6" rod and that would certainly be possible. I have 7" rods in my 340 with it's 3.8" stroke so you have plenty of room and could even go longer. Custom pistons of course, move the pin closer to the ring package but a smaller, lighter wrist pin becomes an option, as do nascar take out rods. If you can score a set of Pankle rods those are SWEET! Must be something like 2 grand a set new but I found a set on ebay for right around $100 very lightly used. I highly recommend them. They are going in John's stroker 300. Bearing inserts might be a little hard to find though. Advantage of the lightest rod/piston package you can manage is that it may be possible to internally balance it. Which then gives you a wide selection of flywheels and dampers. Do you have the 2" rod journals or are they smaller?

Jim


DiDueColpi
Fred Key
West coast - Canada
(1331 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: I think I found a unicorn 2.0
Posted by: DiDueColpi
Date: December 07, 2021 04:34PM

The rod journal is 2.000 inches Jim.
I have enough room to safely widen the journals to 1.500 inches Jukka,
That means that a SBC rod could be used with a little bit of its sideburns shaved off.
The engine will end up at either 4.0L or 4.4L with the current bore.
The Pankle rods are a very interesting option Jim. They look really nice, very light and would certainly be strong enough. It looks like the most common are the 6.2 inch with what looks like a Honda bearing size. Not sure that I want to grind the crank down 0.150 to make them fit though.



Edited 1 time(s). Last edit at 12/08/2021 01:39PM by DiDueColpi.


minorv8
Jukka Harkola

(245 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: I think I found a unicorn 2.0
Posted by: minorv8
Date: December 08, 2021 07:08AM

IIRC my stroker TVR crank had something like 1.5xx wide rod journals. I narrowed a set (actually 2 sets) of SBC rods to fit that crank. I believe the final rod big end width was 19.40 mm (0.763 mm) and I had to machine some 0.090" from BOTH sides of the rod. And yes, finding suitable rod bearings was a bit hard.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6198 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: I think I found a unicorn 2.0
Posted by: BlownMGB-V8
Date: December 08, 2021 10:54AM

I had the same thought but in the end I just went ahead with it. If it's a forged crank I shouldn't think there would be a worry. You will have to run your numbers to see if it all fits with the 6.2" rods. I think it should. I think that's the length I'm using in the 300 strokers and so far no issues. The heads of the capscrews are small enough to clear the inside of the block with no problem. Using a slipper style piston that is quite light. Zero deck and a 30 or 35cc dish.

Those rod caps are pinned and have that wavy mating surface and they go together like the finely crafted pieces they are. No oil squirt hole and no internal pin oiling though. Not a problem with a roller cam or ohc setup.

Jim


DiDueColpi
Fred Key
West coast - Canada
(1331 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: I think I found a unicorn 2.0
Posted by: DiDueColpi
Date: December 08, 2021 02:24PM

The 4.0L rv8 rod is 6.110 inches with a 2.80 inch stroke. So I'll have room for the 6.20 rod on a 2.726 stroke.
The comp height on the rover pistons is very generous so the 3 inch crank and 6.2 rods should have enough room to work as well.


roverman
Art Gertz
Winchester, CA.
(3169 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: I think I found a unicorn 2.0
Posted by: roverman
Date: December 09, 2021 06:53PM

Fred, I like like you thinking. Aren't both Lotus cranks, cast ? Going to ad custom additional counter weights ? Cheap HP is using the exhaust cams on the intake. If/when I can get hold of a new GT 500, flat plane, as a raw forging..... The sbf raw forgings
CAN be machined to fit RV8. Onward, Art.


minorv8
Jukka Harkola

(245 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: I think I found a unicorn 2.0
Posted by: minorv8
Date: December 10, 2021 12:45AM

Here are a couple of photos of the TVR 2,0 litre V8.

My friend has a new flat plane crank for this engine, I had a photo of it but itīs too well archived. Could not find it...

tvr%20s-supercharged%20v8s%20moteur1.jpg

tvr%20s-supercharged%20v8s%20moteur2.jpg


minorv8
Jukka Harkola

(245 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: I think I found a unicorn 2.0
Posted by: minorv8
Date: December 10, 2021 01:05AM

My latest engine has a 91,5 mm stroke i.e. around 3.60" number. The block is a later P38 type cross bolted block. The plan was to use Crower 6 inch rods with Icon stroker pistons. That did not work because the pistons were 60 thou above the deck at TDC and Icon did not recommend machining the pistons down. Top ring land was pretty shallow to begin with. OK, having seen Nascar pistons at Charlotte Nascar musem I realized that you can live with way shallower ring land, at least for couple hundred miles.

I found a set of 5.95 SBC H-beam rods that almost fixed that problem. I only had to machine 10 thou off the pistons, in reality it was closer to 15 thou. Anyway, these rods did not clear the block completely. Maybe because they were later SBC rods for 2.100" pin whereas the Crowers were for earlier 2.000" pin.

Fitting a set of 2.100" rods to a crank with a 2.000" rod journal is another story...



roverman
Art Gertz
Winchester, CA.
(3169 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: I think I found a unicorn 2.0
Posted by: roverman
Date: December 10, 2021 01:59PM

Gen III Hemi's make pretty good power and material above ring is quite thin, 3-4mm. ? This is why they anodized the crowns.
Art.


MGBV8
Carl Floyd
Kingsport, TN
(4267 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

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Re: I think I found a unicorn 2.0
Posted by: MGBV8
Date: December 14, 2021 03:53PM

Don't forget to use a larger ring end gap when the ring is closer to the piston top, Jukka.


phongshader
Justin Brown
Ca
(55 posts)

Registered:
02/19/2010 04:03PM

Main British Car:
Locost Lotus 7 2.3 Duratec

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Re: I think I found a unicorn 2.0
Posted by: phongshader
Date: February 15, 2022 01:06PM

I know this is an old post...looking at forged Lotus 2-2.2 liter cranks, they are around $2k. You can get cast cranks for a bit cheaper but the oil galleys are going to be in the wrong part of the journal for the connecting rods. I like that no custom cams need to be made, which I'm sure is a big cost/time saving. Art is looking at getting raw ford cranks to machine, would it make sense to try and get raw Lotus 2-2.2l cranks to machine? They must exist as there are forged cranks on the market...or maybe get those manufacturers to finish a crank to your specs?


roverman
Art Gertz
Winchester, CA.
(3169 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: I think I found a unicorn 2.0
Posted by: roverman
Date: February 16, 2022 01:43PM

Fred and all, thin part-line on these 2.0 and 2.2L Lotus cranks ? I've looked at a few 2.L cranks, all cast ! Un-boosted V8,with short
stroke, will tend to be low on torque. If you find OEM, 180 deg. V8 cranks to look at, you can measure/duplicate their counterweight
design. Good Luck, Art.


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