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Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Hey guys been a few years. I thought I would start a new thread about rebuilding and porting a MGC factory cylinder head. First off jeez I forgot how damn heavy these heads were smiling smiley Got the head disassembled and degreased, so no interesting pics to show at this time, next will be some media blasting to get everything good and clean so I can get good look at what I working with. I'll analyze the head as is stock, and then show as we starting moving metal in the head. Here's my initial thoughts, the short radius is nicer than most Brit heads (especially the intake) and ton better than anything aftermarket that I have dealt deal, the bowl as for ID is restrictive and need opening up, the intake runners can also use work get them more along the size of where the factory cutter stops. The long radius is decent on the intake, but crappy on the exhaust, I will use the material from the exhaust guide humps to make that better, I am used to that technique from the MGB aluminum head We'll be doing what I call a "street port" where I spend time on the things that make a nice gains, and leave things along that don't , like polished combustion chambers . Looks like I can use MGB intake bronze guide on all ports, will do some shaping of what comes into the port flow, and shortening if necessary. I will share pictures and more data, as I get deeper into the job.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
JMA Avatar
JMA John Anderson
Donvale, Victoria, Australia   AUS
Hal,

You are going to have a fascinated and captive audience, me included.

John

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Ken Plumstead Avatar
Smithers, B.C., Canada   CAN
1965 MG MGB
1968 MG MGC GT
You can count me in too. I'll be sitting on the edge of my seat.

Ken



MG: Transforming gasoline into Fun!!!

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kelleyh51 Gold Member Hiram Kelley
Oklahoma, USA   USA
1953 MG TD
1957 MG Magnette ZB
1958 MG MGA "The Kansas Banker"
1968 MG MGC GT    & more
Me three, looking forward to it!
Hiram

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Steve S Avatar
On The Road, Lost in So Cal, USA   USA
Aluminum heads are a good thing. So much lighter!

Restoman Avatar
Restoman Platinum Member Dana R
amston, connecticut, USA   USA
Hap, perfect timing. Will be following this threat with much interest!
Thanks for sharing!

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
In reply to # 3641657 by Ken Plumstead I'll be sitting on the edge of my seat.

Ken

I know you will grinning smiley



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
Bowral, NSW, Australia   AUS
1968 MG MGC
Welcome Back Hap,

Questions:

Once media blasted do you intend checking for flatness and crack testing before putting too much effort into metal removal?

Cheers, Mick



Mick
Southern Highlands of NSW, Australie

GeorgeOhr Nonya Business
Yes, confused, USA   USA
I'm back too.

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Bowral, NSW, Australia   AUS
1968 MG MGC
Mein Name ist Arnold Schwarzenegger und Ich werde wiederkommen!



Mick
Southern Highlands of NSW, Australie

m.s.macrae Silver Member Murray MacRae
Wellington, Wellington, New Zealand   NZL
1968 MG MGC
1994 Subaru Impreza WRX
2000 Subaru Outback "A Bit Of A Dog"
2008 Mazda 6
Hi Hap,

I remember someone saying that under the valve bosses there is not a lot of meat, in comparison to the Bs and As so not to cut too deep there. Apologies I cannot recall when where or who told me.

So could be totally wrong (only matters if this is a client's head i suppose).

Really interested in this as I have a head sitting waiting my go ahead with the Short block spec (ie the CR-chamber vol question. Brian Hartley here in NZ will do the work.

Murray

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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
In reply to # 3642315 by m.s.macrae Hi Hap,

I remember someone saying that under the valve bosses there is not a lot of meat, in comparison to the Bs and As so not to cut too deep there. Apologies I cannot recall when where or who told me.

So could be totally wrong (only matters if this is a client's head i suppose).

Really interested in this as I have a head sitting waiting my go ahead with the Short block spec (ie the CR-chamber vol question. Brian Hartley here in NZ will do the work.

Murray

Yeah I am not going crazy on them and not trying to totally eliminate them like on a A series head, they have nice shape to them , so I will use them. I think folks probably get into trouble with these heads when the run their die grinder down the back/long radius, which is always a mistake.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
JMA Avatar
JMA John Anderson
Donvale, Victoria, Australia   AUS
My head is going to Head Stud Development here in Melbourne in the New Year.

I'm looking at introducing swirl to the mix rather than outright flow numbers as it's a street engine, and discuss the viability, and/or the possibility, of adjusting the spark plug angle to make the most of that swirl.
We had a Healey in last week with a modified Denis Welch head that I know had the plug angle changed, and must have had good swirl, that produced 620Nm (457ft/lb) of torque at the rear wheels on the dyno last week. I'm trying to get my hands on that printout. For the record it was the late Peter Hopwood's Healey who raced against Denis Welch in 1998.

Bowral, NSW, Australia   AUS
1968 MG MGC
Interesting John...when you say change the angle, do you mean indexing the plugs with washers/shims?



Mick
Southern Highlands of NSW, Australie

JMA Avatar
JMA John Anderson
Donvale, Victoria, Australia   AUS
Mick,

Usually they point the plug tip toward the exhaust valve, I know there's not much space between the pushrod tubes to do this but it seems that some very knowledgeable people have done it.

Further to Peter Hopwood's car, the dyno operator stopped the dyno at 5000rpm as there was no physical documentation to state that the car was fitted with a steel crank. The torque had peaked (was told the curve was broad and flat) but the horsepower numbers were climbing.
What I don't know is what fuel it runs, how much larger the engine is from the standard 2912cc, the cam specs, or who built it. We surmised it was someone in Sydney who REALLY knew their stuff.



Edited 1 time(s). Last edit at 2017-12-10 06:18 PM by JMA.

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