Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Suspension > Front Subframe outrigger disassembly

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
Front Subframe outrigger disassembly  Rate Topic 
AuthorPost
 Posted: 09-02-2019 04:18 am
  PM Quote Reply
1st Post
Max_dvdt
Member
 

Joined: 09-16-2016
Location:  
Posts: 12
Status: 
Offline
I have a 910 conversion underway
- This requires two tweaks to the front subframe:
A) the passenger (US) outrigger needs relieving
B) there is a contact point on the drivers engine mount structure.
C) I suppose a third issue is that the drivers 907 engine mount interferes with the new girdle.

The question today is how do I remove the outrigger (the thing with the yellow paint) I've undone the bolt thru the front suspension lower arm, the bolt thru the steering rack, the frame bolt and the huge lower control arm bolt

but this thing seems glued on...

Thank you...

Attachment: Front subframe2.jpg (Downloaded 52 times)

Last edited on 09-02-2019 04:22 am by Max_dvdt

Back To Top PM Quote Reply  

 Posted: 09-02-2019 12:54 pm
  PM Quote Reply
2nd Post
Brett Gibson JH5 20497
Member
 

Joined: 03-17-2005
Location: Hilton, New York USA
Posts: 761
Status: 
Offline
My understanding is that it is not removable short of cutting it off.
Brett.

Back To Top PM Quote Reply

 Posted: 09-02-2019 09:24 pm
  PM Quote Reply
3rd Post
Esprit2
Member
 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 393
Status: 
Offline
Correct... the Sawzall wrench.

A 910? As in Turbo? What is your plan for the turbo location and plumbing. In the Esprit, the turbo is located behind the cylinder head, where the J-H's cowl is. And the 910's exhaust manifold is shaped to put it there.

A rare Brazilian car, the Emme 422T, used the 910S engine. It had a bespoke exhaust manifold that put the turbo down low and forward. When Emme went out of business, a lot of Lotus guys bought distressed inventory crate motors. The Emme exhaust manifolds were no good to them, so most were scrapped... a few went on shelves.

Regards,
Tim Engel

Back To Top PM Quote Reply  

 Posted: 09-03-2019 04:30 am
  PM Quote Reply
4th Post
Max_dvdt
Member
 

Joined: 09-16-2016
Location:  
Posts: 12
Status: 
Offline
Sorry Tim - not a Turbo...

its a 910 block from Gary Kemp
with a 2.4 stroker crank

Gary made a slight oops and I ended up with a set of Turbo pistons which when I get to that bit will not give me the compression I want- so for about 30 minutes I entertained a supercharger.. but decided in the end to have a set of custom pistons made (path of least resistance)

What I bought:
the 2.4 crank
some billet con rods
the turbo pistons
and nikasil liners

easiest path I see is to just get some custom pistons. I'm guessing that between the crank and conrod billetyness and the nikasil liners a set of stock pistons wont work

Back To Top PM Quote Reply

 Posted: 09-03-2019 03:05 pm
  PM Quote Reply
5th Post
Esprit2
Member
 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 393
Status: 
Offline
The modern composite head gasket has a crushed thickness that is about 0.5 mm / 0.020" thicker than the original steel-asbestos-steel laminated gasket. That raises the head further off the block by that same amount, reducing the compression ratio by about half a point (8.0 becomes 7.5).

When the Goetze composite gasket was introduced in 1993, Lotus started machining the block decks lower by that same 0.5 mm / 0.020" in order to preserve the 'spec' compression ratio. But when the gasket is used on engines built prior to 1993, they loose half a point of compression.

If you're going to order custom pistons, specify a compression ratio that's half a point higher than you really want.

Alternatively, you can have the block's deck cut that much lower, and then cut the liner seats lower in order to preserve the correct 'nip'... ie, the liner's stand-out above the block deck.

*~*~*~*~*
Replace the studs in the block that retain the head. The new gasket requires a higher torque spec that exceeds what the studs can handle... they will yield. Either install the later upgraded Lotus studs, or the ARP studs that are sold by most/ all Lotus parts vendors.

For identification...
The original 907 studs have flat upper ends.
The upgrade 907/ 9XX studs have a depressed dimple machined into the upper ends.

IF you keep the original 907 studs, then you have no choice but to use the original Lotus torque spec so as not to yield the studs. But that low torque will not take full advantage of what the composite gasket offers.

Note that the torque spec given in the Jensen-Healey Workshop Manual is too high for both the original studs and the original steel-asbestos-steel gasket. Mostly the gasket... it would crush, leak again, and you'd be right back where you started.

Lotus reduced that spec to:
70 lbs-ft ( 9.7 kgf-m) Front & Rear Pairs.
75 lbs-ft (10.4 kgf-m) Three Middle Pairs.
Oiled threads & washers.

... but the J-H manual's torque spec was never updated.
But then, the original gasket is no longer available.

Regards,
Tim Engel

Last edited on 09-05-2019 07:09 pm by Esprit2

Back To Top PM Quote Reply  

 Posted: 09-04-2019 03:17 pm
  PM Quote Reply
6th Post
Esprit2
Member
 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 393
Status: 
Offline
Have you talked with Gary Kemp about the pistons you have and the compression they will produce? The stroker crank's longer stroke would normally drive any stock pistons too far up the bore, and they would hit the head. To prevent that, either the rods need to be shorter, or the wrist pin bores must be higher up on the pistons (Lotus did that between the 2.0 & 2.2), or a combination of both.

It's possible, that the low compression Turbo pistons would have created a 'high performance' compression ratio with the appropriate length rods on the long stroke crank.

If you do pursue custom pistons, then know before you order just what wrist pin height is required in order to work with the 2.4 crank and whatever the length of the new rods is.

All that comes first. Then allow for the loss of compression due to the thicker composite gasket.

What vintage is the 910 block you have? If before Jan 1993, then it has the old, higher deck height, so the composite head gasket will lower the compression ratio about half a point.

If block was produced after Jan 1993, then the deck heigh was cut 0.5mm / 0.020" lower to allow for the thicker composite gasket.

All that needs to be coordinated in order to successfully build a composite engine out of a mixed bag of parts.

The easiest 'out' would be for you to put the Monkey on Kemp's back to provide you with the correct pistons to work with everything else he has already sold to you.

Regards,
Tim Engel


Max_dvdt wrote:
Sorry Tim - not a Turbo...

its a 910 block from Gary Kemp
with a 2.4 stroker crank

Gary made a slight oops and I ended up with a set of Turbo pistons which when I get to that bit will not give me the compression I want- so for about 30 minutes I entertained a supercharger.. but decided in the end to have a set of custom pistons made (path of least resistance)

What I bought:
the 2.4 crank
some billet con rods
the turbo pistons
and nikasil liners

easiest path I see is to just get some custom pistons. I'm guessing that between the crank and conrod billetyness and the nikasil liners a set of stock pistons wont work

Back To Top PM Quote Reply

Current time is 09:27 pm  
> Jensen Healey & Jensen GT Tech > Suspension > Front Subframe outrigger disassembly Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems