Jump to content

mk2 head wrecked?


Recommended Posts

  • Replies 115
  • Created
  • Last Reply

So the plan will be to run these along to Maynards for them to cast an expert eye over them after cleaning, to assess which is the most viable as a donor for the car, in the role of mk3 'Go-faster' head.

1st job- assess likely skim required and do that 1st off all, before any other expense spent!!!!!! ;D
10.5/1 CR
Unleaded conversion
Gas flowed
New guides
CW or other valves I have
3 angle seats
MBE for services to forum entertainment :-/?

Link to comment
Share on other sites

Fingers all crossed, but I am sure it will be 3rd time lucky :)
One day we will see how yours compares with my spitfire at a trackday. Probably 2011 the way mines progressing, or rather not. Yours will be sorted PDQ now I expect! CLM??

Link to comment
Share on other sites

I hope this hasn't been discussed before, but have you considered measuring the thickness of the head face?
Obviously, in a non-destructive way.
Ultrasound is your answer - see: http://www.olympus-ims.com/en/25hp-plus/

No idea how much this gadget is.  Medical ultrasound imagers are in five figures of pounds, but this isn't an imager, just a thickness gauge -simpler, but more powerful.   If your machine shop don't have one (and why should they?) they may be able to find someone who does, who will scan you head for a fee that might be less than re-doing a ruined head.


Link to comment
Share on other sites

Classic Le Mans? Doubtful :B. Car will be ready, but CLM isn't factored into the years festivities.
Fear not Clive, the automotive sap is indeed rising ;). Stoneleigh should be a go-er. Hoping for another cross-country blast like last year with the usual suspects 8).
I'm off to Maynards to see them on Friday and go through my hopes and intentions in detail. I'm getting excited about cars again!

i'm also going to try to get the head Ultrasonic examined at work. Not sure their devices will work in this application but, it wont cost anything but my time.

Link to comment
Share on other sites

Dropped off the two heads at Maynards today. A fun filled time spent pouring over them with Mark and his 'new apprentice'. It really is an excellent set-up they have there 8). They will assess which of the two heads offers the best potential for my application.
Much like a number of you here, their long term solution for my engine is:
Deck block- ouch!
fit the right cam :B
Gasflow the head to match the new cam profile
Work out which of my valves suits the plan

However, that's for the longer term i'm afraid. The short term plan is to get  a head fitted that gives at least 9.5/1 once its been gas flowed! I'll let you know how we get on. :)

Link to comment
Share on other sites

I may have painted an in-accurate picture of the long term plan :B. If we use for example the GT6 head(ta Nick!), this is already .007" under height, but as the combustion chamber hasn't had any material removed, the bare minimum will need to be removed to get at least 9.5/1 CR or probably somewhat better still. There does appear to be loads of metal left in both heads for skimming..... Realistically, I'll just as likely to have to accept less than 10.5/1 CR by this gas-flowing and skimming of this head alone- The final decking of the block will remove 2.5cc per cylinder, let alone allowing the pistons to 'pop-up'.

But, all this is somewhat dependant on what there assessment of the heads potential is, which valves to fit (shrouding effects etc.) what the current combustion chamber volume is etc.

Marvellous! :)

Link to comment
Share on other sites

  • 1 month later...

Picked up the 'new' head today. Crikey-Moses! 8) ;D
10.3/1, gas flow figures to make your bladder give way and to say i'm pleased is an understatement.
Roy- keep your eye on your rear view mirror baby!!!!
Mark Maynard (the machine shop owner) and Gareth Thomas have worked a bloomin' marvel here. You all know the last head broke the bank. These guys have lavished their time and energy and not billed me for at least 60% of the time and work done.
The amount of time they've spent on the gasflow rig with this head and sorting out the inlet runners is mind-boggling :). Just look at the amount of metal GT had to remove from the inlet manifold to overcome a previously un-diagnosed airflow issue!!
Burning the midnight oil is an apt expression, as both Mark and Gareth were working on these items until silly o'clock on more than a few ocassions.
They knew my position financially, but still took on the work and effected a job way outside the actual money they charged me.
Well done guys- I'm very grateful :).

So we know what my job for tomorrow is! ;D

Link to comment
Share on other sites

In am HUGELY relieved that it has all come together. You needed a break!
So, job for today....down to weigh in the ali that has been removed ;)
then maybe a little fettling to the car? And hopefully when I get home tonight a report on the difference it all makes? should be significant!

Link to comment
Share on other sites

Productive day today, around housework and the gym.
Head down to 3.250", so all the tappets needed some tightening up somewhat. Loads of little jobs done with cable linkages and choke cable stuff, hose issues and trying to find the Kenlowe  fan- where did I put that????
Bit more fiddlin' to do before start up tomorrow :).

Link to comment
Share on other sites

Finally found the Kenlowe in the garage- in a safety boot box( )
Drained the old oil- it was less liquid engineering, more like a thick chocolate milkshake.
Found the missing rocker shaft retaing screw- attached to the magnetic sump plug money well spent there.
Fitted new oil filter.
Tested the electrics- fuel pump wouldn't run. After a lot of investigation, it turns out the electric fuel pump pressure isolation switch failed. By-passed that using a spare 'white' wire from the ignition.
Then time to start it.
Turned over for some time, then a ker-fuffle of life, and just as the battery was getting saggy- VVVVVROOOOOM!

So, obviously not tuned and the laptop not connected, meant 'choking' it more than i would have liked(it barely needed any choke in the past, but soon was hot enough to begin tuning.
However, there was a marked tendancy to backfire from number 3 carb .
At this stage, there was no manifold balance pipe fitted. After some high comedy moments with earth shattering backfires sending the temporary blanking manifold plug skywards .
So, the perfect opportunity to try a contrast and compare with the new manifold balance pipe....
A quick 'rough fit' with that seemed to remove the backfiring!
Fitting the balance pipe in a more sealed and permanant manner embued the engine with a balanced and even tickover and no apparrent backfiring or fuel vapour evident at the carb throat!!!!!!!!

So, good to see me and Roy's unguided tour of Lincolnshire bending the temperature gauge needle doesn't seem to have stripped the bearing shells of their linings- still got good oil pressure too.
This was all done a bit late in the day today, so looking forward to a day fettlin' the state of tune and fitting some replacement hoses and bits and we should be looking good for a RR session prior to Stoneleigh.

Link to comment
Share on other sites

bobyspit wrote:
Bruce, No photos of the head?

Come on mate you know we want to see it.


Hi Rob.
The developments GT's made of late with port and chamber work are such that it would be inappropriate for me to put pictures on line. If Gareth wants to put them online- thats up to him. He spent hours and HOURS on the flow bench doing these, so it would be unfair to put that all in the public domain :).
So excited!!!!!!

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...