Uh Ohh
Turbo Mini Forums

Whilst the engine is running if you remove the oil filler cap and the revs drop and it starts running like a bag of balls thats a head off jobbie isn't it?

not if its running pcv ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

pcv? i thought us IT bods were acronym crazy!

positive crankcase ventilation . so the breathers go into the inlet manifold under vacuum .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Whipped the head off with the brother as i finished work early.



Something doesnt look quite right does it...

eek!
is this on the turbo?

Team Racing

No, on the original Axel's mini 30.
12G295 head has only been on a few months, we're going to take the one off my old car and put it on this.

We did think the performance seemed a little slow compared to mine for the same spec...

did you do a compression or leakdown before taking the head off?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Nope, the old man is still away sunning it up in france and i'm not sure where the compression tester is.
The filler cap removal issue and that light valve suggest intake leak to me, is that right?
Whatever it is its running very lean on 2.

Edited by sturgeo on 14th Apr, 2010.

i cant see owt wrong with it ,ill get my magnifying glass .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Schrödinger's cat - so which one am I ???

Sorry Rod, i meant to say 2 instead of 3.
I thought light coloured exhaust valves meant it was running lean?
3 looks as if its running very rich aswell.

Pop your valves out and see what the seats and guides look like

Edited by Rod S on 14th Apr, 2010.

Schrödinger's cat - so which one am I ???

Have you removed no 3 spark plug a bit as i cant see the end protruding into the chamber at all??

Luke

We have losened them all off but it is still slightly visable, just completely caked in carbon.

Your fueling must be good Rod as they are all pretty close colour wise

Bloody Hell.

Can't leave you lot alone for two minutes. I get home from holiday and they've got cylinders heads off two cars doing a swap

Most likely something simple in the first place. That's the rest of my holday gone up the swannie :(

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

lol

If something is worth doing, it's worth doing half of.

There is definately something wrong with the exhaust seat and valve on No. 2.

The valve has been blowing and there is a deposit around the joint beetween the valve seat and head.

EDIT: Morspeed did the head work by the way.

Edited by Paul S on 15th Apr, 2010.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

That could explain why No 2 is different to the others if a leak has been "overheating" it, but the other three are all far too cool (or too rich) IMHO.

Shame there were no compression test results first.

If they are unleaded inserts, you (all three of you) were lucky it didn't drop out if its been leaking behind the seat on No2.

I have an A-Series head where an exhaust seat did drop out and the bits that didn't go down the exhaust made a right mess of the cylinder bore.

Schrödinger's cat - so which one am I ???

I think that it looks all black because they did some simple diagnostics with it on choke.

It was all set up with a wideband a few months ago, so i do not think it is a mixture issue.

It is an unleaded insert that is leaking.

They are going to fit the head off the Flame whilst we get this sorted.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Axel is fitting the other head and we should have it running this afternoon.

This appears to be the problem:






I recall that we had problems with cutting/seating the valve when we built the head up. We thought that we had done enough to create a decent seat. Would that cause this problem?

EDIT: Even got the MD helping:

Edited by Paul S on 17th Apr, 2010.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Is it an unleaded insert or not ???

As the area of lack of seating is an even arc about 1/3 circumference (of the seat) I would normally say guide is eccentric, ie a new guide was fitted and the seat wasn't recut with the pilot in the new guide. New guides are never on the same centre as the removed one.....

But if it's an unleaded seat, it's possible it wasn't fully located when it was pressed or shrunk in and has since tipped slightly. Pressed in ones are far more suceptible to this than shrunk in ones (liquid nitrogen installation).

Schrödinger's cat - so which one am I ???

Yes it is an unleaded insert.

I think that the tipping theory has some merit.

EDIT: Shot from a different angle:

Edited by Paul S on 17th Apr, 2010.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."