Home 
Home Search search Menu menu Not logged in - Login | Register

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
907 vs 910  Rating:  Rating
AuthorPost
 Posted: 07-17-2006 04:15 pm
  PM Quote Reply
1st Post
OverdriveGear
Member


Joined: 06-01-2005
Location: Gainesville, Georgia USA
Posts: 17
Status: 
Offline
Hello everyone, I was wondering about the similarities/differences between the 907 series and 910 series.  I just recently saw you could "hybrid" the two together and I thought that was pretty neat.  Obviously the top end will be probably identical, but what about the bottom end?  Would a 910 crank fit in a 907 block, bearings different, etc?

Back To Top PM Quote Reply  

 Posted: 07-18-2006 03:56 am
  PM Quote Reply
2nd Post
Judson Manning
Member


Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Status: 
Offline
Erik Harkes put a 907 bottom-end on a 910 top-end.  I went the other direction and put a JH top-end on a 910 bottom-end.  My decision to build a 'hybrid' was driven more by available parts than any other reason.

Keep in mind the 9xx series engine continued to evolve through circa 1999(?), there were a LOT of running changes.  In general, most part are interchangeable without modification including the cranks.

The exception is the bottom half of the block.  Below the split-line of the main bearing panel is where the 910/912/911/920 depart significantly from the 907.

http://jhppg.com/gallery/album08/P1010012

Post ~1986 blocks (i.e. HCI, Excel SE, etc.) use aluminum liners with Nikasil coatings instead of the 907 iron liners.  The aluminum liners are 1mm larger in diameter so you can't put them in a 907 or vice versa.

Unless you are itching for a project, I can't suggest the 'hybrid' route.  Instead, I would suggest finding a 1988 Lotus Excel SE engine or an engine from a N/A Esprit to rebuild and transplant into your JH. 

These are really the most 'evolved' engines, and have all the HP goodies you will need.  The only problem is finding one as neither are exactly common.

Back To Top PM Quote Reply

 Posted: 07-18-2006 06:15 am
  PM Quote Reply
3rd Post
edward_davis
Member


Joined: 07-06-2005
Location: Eugene, Oregon USA
Posts: 162
Status: 
Offline
I remember reading somewhere thet the 9xx slant fours were meant as a precursor to a V-8, but that eight was never built.  But that was an old source, and I know Lotus made an eight-powered Esprit near the end of its run.  Was that eight based on the 9xx, or was it a souped-up version of another company's engine, much like the four in the Elise?

Back To Top PM Quote Reply  

 Posted: 07-18-2006 03:34 pm
  PM Quote Reply
4th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Lotus developed the LT5 Corvette engine for GM in the 1980's. It has the "bearing panel" design of the 907 as does the Northstar engine. These engines were certainly not two 907s grafted together but the technology carried forward.

The Lotus v8 was a product of Lotus and not another companies design. It used current racing knowledge to develop a lightweight v8 that would fit in the Esprit.

There's lots of info on the web.

Kurt 

Back To Top PM Quote Reply

 Posted: 07-18-2006 03:48 pm
  PM Quote Reply
5th Post
jcdean
Member
 

Joined: 02-22-2006
Location: Oklahoma City, Oklahoma USA
Posts: 169
Status: 
Offline
Isn't the biggest issue with the 910 and later variants the fitting into the smaller mounting area in the JH?

 

Joey

Back To Top PM Quote Reply  

 Posted: 07-18-2006 04:55 pm
  PM Quote Reply
6th Post
Judson Manning
Member


Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Status: 
Offline
Yes Joey, you are correct.  Click on the link I included above and you will see the 910 bottom end is significantly larger.  A 910 will fit, but some minor modification of the mounts and x-member are necessary.

Back To Top PM Quote Reply

 Posted: 07-18-2006 05:54 pm
  PM Quote Reply
7th Post
jcdean
Member
 

Joined: 02-22-2006
Location: Oklahoma City, Oklahoma USA
Posts: 169
Status: 
Offline
Thanks for the confirmation.  I have looked all over for a 910+ engine with no results anyway.  Well, with results that make it affordable at least.  They are a rare breed.

 

Joey

Back To Top PM Quote Reply  

 Posted: 02-05-2012 08:21 pm
  PM Quote Reply
8th Post
JodyKerr
Member


Joined: 05-15-2006
Location: Tempe, Arizona USA
Posts: 217
Status: 
Offline
Bumping this topic. Anyone have pictures or more specific information on the chassis modifications necessary to install the 910 block?

Back To Top PM Quote Reply

 Posted: 02-05-2012 10:16 pm
  PM Quote Reply
9th Post
jcdean
Member
 

Joined: 02-22-2006
Location: Oklahoma City, Oklahoma USA
Posts: 169
Status: 
Offline
I have been looking for four years now for a US sourced 912. With the added statement that this has not been a full time search I have not found one. On the other hand there is Lotubits in the UK. They have everything I need including Dell'Orto's and the cost is not prohibitive. I have not found a real quote for shipping there though other than FedEx or UPS which doubles the cost. But, I can dream.

Back To Top PM Quote Reply  

 Posted: 02-06-2012 03:11 pm
  PM Quote Reply
10th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Subwoofer did it.

http://www.jensenhealey.com/forums/view_topic.php?id=1209&forum_id=15&highlight=modified+sump

Scroll down to the 40th post

Back To Top PM Quote Reply

 Posted: 02-08-2012 08:26 pm
  PM Quote Reply
11th Post
subwoofer
Member
 

Joined: 04-01-2008
Location: Sandefjord, Norway
Posts: 617
Status: 
Offline
Jensen Healey wrote:
Subwoofer did it.

http://www.jensenhealey.com/forums/view_topic.php?id=1209&forum_id=15&highlight=modified+sump

Scroll down to the 40th post


Please note that it is a later 907, NOT a 910/912, so it still has the narrow bearing panel.

--
Joachim

Back To Top PM Quote Reply  

 Posted: 02-08-2012 08:30 pm
  PM Quote Reply
12th Post
subwoofer
Member
 

Joined: 04-01-2008
Location: Sandefjord, Norway
Posts: 617
Status: 
Offline
edward_davis wrote:
I remember reading somewhere thet the 9xx slant fours were meant as a precursor to a V-8, but that eight was never built.

I have also heard rumours of that 907 based V8. I can't quote any sources, but I think I remember hearing that it actually ran and made lots of power, but they just couldn't make it keep the cam belt(s) on. Again, heresy and possibly faulty memory.

--
Joachim

Back To Top PM Quote Reply

 Posted: 02-08-2012 09:53 pm
  PM Quote Reply
13th Post
JodyKerr
Member


Joined: 05-15-2006
Location: Tempe, Arizona USA
Posts: 217
Status: 
Offline
Hey All,

 

I was able to find someone who had fit the 910/912 to a Jensen Healey in the past. Based on their information it apparently involves some shimming of the engine mounts and the cut of a small notch in the passenger side of the sub frame. And this information is reliable.

 

When I get my hands on said block I'll double check this information, make the necessary modifications and do my usual documentation of the process.

Jody

Back To Top PM Quote Reply  

 Posted: 02-09-2012 10:04 pm
  PM Quote Reply
14th Post
James Sohl
Member
 

Joined: 04-24-2006
Location: Chandler, Arizona USA
Posts: 18
Status: 
Offline
Lotus did make a V8 based on the 907, it think is was the type 908.  At least one prototype was made, but no production.  There was also a prototype car, the Etna, a luxurious model that was never made, that would have been 908 powered.  This all occurring well before Lotus and GM got together on the GM 4-valve engine.

Back To Top PM Quote Reply

 Posted: 02-11-2012 04:25 am
  PM Quote Reply
15th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Thanks James! Here's some info and photos of the Lotus 909:

 

http://www.projectm71.com/Rudd.htm

http://www.lotusbuzz.com/forums/showthread.php?t=697 


 

Back To Top PM Quote Reply  

Current time is 06:37 am  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > 907 vs 910 Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems