74 replies to this topic

[blacktulip]

Ok. So 47bhp and 60 torque on a standard small valve head and cast manifold.

Pulls like a train and chuffed to bits with the 3.1 diff on the L2B run.

So, and here's the six million dollar question, will putting a 295 head on, mani flow free flow outlet and an inlet make much difference to the torque?

Very tempted to leave as is unless there are gains to be made.

Any advice appreciated.

Mike

if you wait a month or so i will let you know as my spec will be the following.

 

+60 rebore (1046cc)

MD266 cam

Flat top pistons

12G295 head fully reconditioned, new guides, new unleaded seats, valves seats recut and lapped in.

Reground crankshaft

Vernier Duplex timing gear

25D Dizzy to be recurved on RR session with electronic ignition

CR to be around 10:1

Lightened flywheel

standard gearbox with 3.44 FD

Howley 1 inlet manifold ports matched to head

Maniflow Freeflow exhaust manifold

RC40 twin box

HIF38 Vizard mods (needle made on RR session)

k+n element filter

Minispares supercool rad

 

i was thinking about a 3.1FD but i am worried it will kill the performance.

[timmy850]

You should get a reasonable gain by the traditional stage one kit - manifolds especially. 

 

You'll just have to make sure the 295 head has the right size combustion chambers to get a decent compression ratio... 

[lawrie124]

Ok. So 47bhp and 60 torque on a standard small valve head and cast manifold.
Pulls like a train and chuffed to bits with the 3.1 diff on the L2B run.
So, and here's the six million dollar question, will putting a 295 head on, mani flow free flow outlet and an inlet make much difference to the torque?
Very tempted to leave as is unless there are gains to be made.
Any advice appreciated.
Mike

if you wait a month or so i will let you know as my spec will be the following.
 
+60 rebore (1046cc)
MD266 cam
Flat top pistons
12G295 head fully reconditioned, new guides, new unleaded seats, valves seats recut and lapped in.
Reground crankshaft
Vernier Duplex timing gear
25D Dizzy to be recurved on RR session with electronic ignition
CR to be around 10:1
Lightened flywheel
standard gearbox with 3.44 FD
Howley 1 inlet manifold ports matched to head
Maniflow Freeflow exhaust manifold
RC40 twin box
HIF38 Vizard mods (needle made on RR session)
k+n element filter
Minispares supercool rad
 
i was thinking about a 3.1FD but i am worried it will kill the performance.

So not dissimilar to mine. What bhp and torque are you expecting ?

As for the diff, I previously had a 3.44 but any form of motorway driving was unbearable, and no way was I doing a trip to the ring at a continual 5000rpm.

Edited by lawrie124, 20 May 2015 - 04:51 AM.

[lawrie124]

You should get a reasonable gain by the traditional stage one kit - manifolds especially. 
 
You'll just have to make sure the 295 head has the right size combustion chambers to get a decent compression ratio...

Now we are getting into territory I have read about but have never put into practice! The head has been ported and skimmed I think and a mate is going to take the valves out and lap them in with new oil seals.

[timmy850]

Cooperman on here has gone into the calculations a few times.. Essentially you want a C/R the same or higher when going for more performance. You can measure the volume using a burette or a plastic syringe from the chemist.

 

There is a list of the stock combustion chamber sizes here:

http://www.calverst....casting_ no.htm

[blacktulip]

you should find an earlier topic i asked helpfull

http://www.theminifo...th-12g295-head/

[blacktulip]

http://www.theminifo...eight-to-block/

and this one

[lawrie124]

Thanks Timmy and Blacktulip.

[lawrie124]

Big valve head going on tomorrow, weather permitting.

Lapping those valves in was a right pain.

Attached Files

•  image.jpg   96.21K   5 downloads
•  image.jpg   108.8K   6 downloads

[lawrie124]

New head fitted, and maniflow free flow etc.

Pulls like a train! Well chuffed. Just a bit hesitant at about 3000 rpm.

Just need to extract a heater valve takeoff stud I snapped this evening then get the timing and CO checked.

Happy days.

Mike

[coopdog]

Ok. So 47bhp and 60 torque on a standard small valve head and cast manifold.

Pulls like a train and chuffed to bits with the 3.1 diff on the L2B run.

So, and here's the six million dollar question, will putting a 295 head on, mani flow free flow outlet and an inlet make much difference to the torque?

Very tempted to leave as is unless there are gains to be made.

Any advice appreciated.

Mike

And I'm guessin that's at the wheels? And around 60 at the flywheel?

[lawrie124]

Ok. So 47bhp and 60 torque on a standard small valve head and cast manifold.
Pulls like a train and chuffed to bits with the 3.1 diff on the L2B run.
So, and here's the six million dollar question, will putting a 295 head on, mani flow free flow outlet and an inlet make much difference to the torque?
Very tempted to leave as is unless there are gains to be made.
Any advice appreciated.
Mike

And I'm guessin that's at the wheels? And around 60 at the flywheel?

Not sure. My recollection from having the TVRs on the rollers is that is engine as they measure at the wheels then take into account drivetrain loss.

[blacktulip]

Sounds good. Should be really good after the rolling road.

[lawrie124]

Have to wait until mid July to get a Saturday appointment on the same rollers, which is a shame.

Won't know what difference the big valve head and maniflow free flow makes until then.

[lawrie124]

So it was on the rollers this morning.

Chart below is a comparison between standard head and manifold with LDP1 and the new head, maniflow free flow and inlet.

Basically power up from 47 to 55 and torque higher throughout the range and doesn't drop off till further up the scale.

Well chuffed.

Attached Files

•  image.jpg   39.86K   12 downloads