20 replies to this topic

[Turbo Phil]

The combustion chambers, while the most important, are the cheapest element of modifying a cylinder head, as it is now done with a computer programmed milling machine, whereas it used to be done by hand using a pantograph from a template.

Not in my workshop. Lol. All hand done here.

Phil.

[DeadSquare]

 

The combustion chambers, while the most important, are the cheapest element of modifying a cylinder head, as it is now done with a computer programmed milling machine, whereas it used to be done by hand using a pantograph from a template.

Not in my workshop. Lol. All hand done here.

Phil.

 

 

By candle light, with your children powering the treadmill  ?

 

 

[Turbo Phil]

I'm happy enough with how they turn out.

Phil.

Edited by Turbo Phil, 20 September 2018 - 11:37 AM.

[DeadSquare]

In the late 1950's, I took the cylinder head from my mother's Morris Minor to Daniel Richmond at Downton.

 

I watched as it was bolted in front of their prepared head on a slab of steel, put under a Pillar drill and a 3/8" ball-ended cutter brought down and locked in one of the spark plug holes, with an index in the same position in their prepared head.

 

With the drill running at a very high speed, the fitter slid the slab with the heads on, over the table and reproduced their profile in mother's head.

 

It took about 1/2 hour and cost 21 shillings.

[nikollou]

@Phil

I have a question for you:

 

When modifying a head for forced induction applications what is the principle around enlarging the intake port throats?

 

I know that for N/A they should not be enlarged almost at all, as this will reduce the velocity of the air and that will cause a drop in performance (at least that is what I read in Vizard's guide and was told by a couple more experts).

 

Does this also hold for Forced Induction heads? Or maybe due to the presence of the turbo the air already has enough velocity, so enlarging the intake ports actually produces better results?

 

Cheers,
Nik

[Turbo Phil]

A turbo increases charge density, not port velocity. For a road going engine I size the port throat at 87-88% of the valve diameter.

Phil.