Some "Dynomite" Heads! - ZR-1 Net Registry Forums

Locobob · 12-20-2010

Just getting started on Dynomite's head porting so I thought I'd share as I go along. Some interesting measurements from the stock (untouched) heads:

Combustion Chambers came in around 41cc with not much deviation, this was using my own method and a spark plug in the hole.

Intake runner dimensions:
Diameter at IH gasket surface: Primary 32.3mm, Secondary 36.4mm
Diameter, narrowest point of runner: Primary 32mm, Secondary 32mm (just upstream of valve guide)
Runner width at valve guide: Primary 33mm, Secondary 33mm
Valve seat diameter: Primary 34.7mm, Secondary 34.7mm

Exhaust port dimensions:
Valve seat diameter: 32mm
Width across valve guide: 34.8mm
Runner narrowest point: 31.5mm (where ports merge into one)
Header gasket surface: 51.8mm long, 35.6 tall

Locobob · 12-20-2010

Some close ups of the chambers:

The worst areas are hard to see, sharp edges and poor transitions an inch or so above the valve seats.

Locobob · 12-20-2010

Looking down the intake runners:
It would appear from the measurements I made that the two runners are mirror image castings with only the machining done to the top of the secondary port differentiating them.

Exhaust ports:

Here is the template I made off the bottom of the injector housings which I had enlarged only slightly. You can see just how skewed the port alignment is from the factory. It is noticeably worse on the primary runners, secondaries are closer probably due to the machine work done on these.

And marked on the head without the template

mgbrv8 · 12-20-2010

Excellent work Sir, keep the pictures coming.

Polo-1 · 12-20-2010

are those the fire sale heads

Kevin · 12-20-2010

glad to see your heads getting some love

tomtom72 · 12-21-2010

( insert wolf whistle here ) It's nice to see your car getting some head work dunn

Tom

A26B · 12-21-2010

Great pictures Bob. When I first started making gaskets, I used LT5 engine drawings & made them to that spec. Scared the bejesus out of me when I check fit to early style engine parts.

Looking forward to seeing the entire series, all the way to the finish line.

FU · 12-21-2010

Quote:

Originally Posted by A26B

Great pictures Bob..

Looking forward to seeing the entire series, all the way to the finish line.

Agreed

GOLDCYLON · 12-21-2010

Quote:

Originally Posted by Dynomite

No (that is a long story)....by the way..the fire sale heads are very nice

we need to chat about those heads cliff

12-20-2010	#1
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,057	Some "Dynomite" Heads! Just getting started on Dynomite's head porting so I thought I'd share as I go along. Some interesting measurements from the stock (untouched) heads: Combustion Chambers came in around 41cc with not much deviation, this was using my own method and a spark plug in the hole. Intake runner dimensions: Diameter at IH gasket surface: Primary 32.3mm, Secondary 36.4mm Diameter, narrowest point of runner: Primary 32mm, Secondary 32mm (just upstream of valve guide) Runner width at valve guide: Primary 33mm, Secondary 33mm Valve seat diameter: Primary 34.7mm, Secondary 34.7mm Exhaust port dimensions: Valve seat diameter: 32mm Width across valve guide: 34.8mm Runner narrowest point: 31.5mm (where ports merge into one) Header gasket surface: 51.8mm long, 35.6 tall __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368

12-20-2010	#2
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,057	Re: Some "Dynomite" Heads! Some close ups of the chambers: The worst areas are hard to see, sharp edges and poor transitions an inch or so above the valve seats. __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368

12-20-2010	#3
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,057	Re: Some "Dynomite" Heads! Looking down the intake runners: It would appear from the measurements I made that the two runners are mirror image castings with only the machining done to the top of the secondary port differentiating them. Exhaust ports: Here is the template I made off the bottom of the injector housings which I had enlarged only slightly. You can see just how skewed the port alignment is from the factory. It is noticeably worse on the primary runners, secondaries are closer probably due to the machine work done on these. And marked on the head without the template __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368 Last edited by Locobob; 12-20-2010 at 01:08 AM.

12-20-2010	#4
mgbrv8 Join Date: Jul 2009 Location: Texas Posts: 793	Re: Some "Dynomite" Heads! Excellent work Sir, keep the pictures coming.

12-20-2010	#5
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: Some "Dynomite" Heads! are those the fire sale heads

12-20-2010	#6
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: Some "Dynomite" Heads! glad to see your heads getting some love __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

12-21-2010	#7
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Some "Dynomite" Heads! ( insert wolf whistle here ) It's nice to see your car getting some head work dunn Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

12-21-2010	#8
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: Some "Dynomite" Heads! Great pictures Bob. When I first started making gaskets, I used LT5 engine drawings & made them to that spec. Scared the bejesus out of me when I check fit to early style engine parts. Looking forward to seeing the entire series, all the way to the finish line. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.