Forty Year Old David Vizard Combustion Chamber Still Viable?

[Vintagewrench]

Vizard.jpg

unnamed (2).jpg

A gentleman I met has this David Vizard modified 1.8L Volvo B18 pushrod head visible in the first photo which Vizard did for him 40-years ago in London, England. The second image shows a standard unmodified chamber.

I'm ready to start on another head, with a new chamber and port shape for next years vintage racing season with my own B-18 powered Volvo. My question is if this Vizard chamber shape would be a good model to pattern my new chamber shape.

Here is what he remembers about about the mods he had done to his engine: "I lived in Hackney back in the early 70’s and was torn between Ruddspeed and an upgrade to Volvo performance stuff from TAD in Finchley. Ended up with hi performance mods from TAD. But it was not overly impressive."

"So went next instead to local speed shop in Leytonstone where I became very good friends with the proprietor George Gur. He introduced me to David Vizard who built me a killer head. It went onto my B-18 bored to 2L and Derrington Motors in Reading supplied twin 40DCOE18 Webers with tri-y headers and large bore Simons exhaust.

"Vizard worked on the head in the basement of his house in London. He did his head work using only hand tools except of course for shaving the head. This head with 11:1 CR put me at about 140 RWHP (standard flywheel HP was 95.) I’ve attached a picture of it here just prior to its most recent valve job. As you can see one cylinder had a leaking valve guide."

"The bottom half of the motor ran out of steam at around 940,000 miles. The head is still totally functional and in use 1.2 million miles later.
Somewhere in a box I have the paperwork. I can recall using race guides that were chamfered into the combustion chambers, the chambers being cc’d to be exactly the same as each other, the pushrod holes being opened to accommodate the roller rocker geometry, large satellite faced valves, and some other stuff I can’t remember having to do with swirl characteristics."

"Today this head is on a 2.3L B-20 stroker, same Webers, with direct port nitrous and water/methane, roller rockers and much much more."

[panic]

He may answer you

[Erland Cox]

Here are some pictures: http://www.topplocksverkstan.se/referenser2.html

Erland

[Vintagewrench]

Thanks Erland, Your work is excellent as well and widely known in The Volvo world.

This head looks like a full out effort to makes lots of power. If you are willing to share what CR is this head?

[mag2555]

Looks like a nice burn pattern, but I would have liked to have seen the chambers as they came off the motor to look for signs of fuel wash.

One thing that looks ripe for improvement this time around would be running a extended tip, or longer shimmed plug to get the flame started off more to the center of the chamber.

[williamsmotowerx]

Here are some pictures: http://www.topplocksverkstan.se/referenser2.html

Erland

Looking at your intake port mold, it looks like there could be a lot to be gained with your SSR. Is there a reason that it's the way it is?

[Erland Cox]

This head was for a flow and dyno competition with a minimum chamber cc.
I believe the compression was only 11,5:1.
I do not want to mill the heads more than 3mm:s so I try to make the chambers as small as possible.
12,5:1 on our pump fuel is no problem, 16 bars on the compression tester.

To give an answer in the SSR I must know what you would like to change.
The reason it looks like it does is making an as gradual turn as possible without hitting water.

Erland

[mag2555]

The Exh port does not look too good and it would be my guess that in terms of porting work that the Intake side could way over ratio what could be improved upon on the Exh!

Anyway before anything is guessed at, let me ask what are the valve sizes and what is the minimum diameter of the throat in each valve bowl?

If they are not atleast at a 85% ratio then there's a good chunk more of air flow to be had.

[Vintagewrench]

PICT0002-9.jpg

PICT0003-6.jpg

The basic design of these Volvo pushrod head ports was laid out in the late-1950s and of the two the exhaust port (lower photo) is the the most challenging to get to flow well as there is only so much that can be done to them because of the shape of the castings and the water jacket. One of the modifications that improves the exhaust port flow is to braze or weld and raise the floor of the exhaust ports.

[David Vizard]

Vizard.jpg unnamed (2).jpg


A gentleman I met has this David Vizard modified 1.8L Volvo B18 pushrod head visible in the first photo which Vizard did for him 40-years ago in London, England. The second image shows a standard unmodified chamber.

I'm ready to start on another head, with a new chamber and port shape for next years vintage racing season with my own B-18 powered Volvo. My question is if this Vizard chamber shape would be a good model to pattern my new chamber shape.

Here is what he remembers about about the mods he had done to his engine: "I lived in Hackney back in the early 70’s and was torn between Ruddspeed and an upgrade to Volvo performance stuff from TAD in Finchley. Ended up with hi performance mods from TAD. But it was not overly impressive."

"So went next instead to local speed shop in Leytonstone where I became very good friends with the proprietor George Gur. He introduced me to David Vizard who built me a killer head. It went onto my B-18 bored to 2L and Derrington Motors in Reading supplied twin 40DCOE18 Webers with tri-y headers and large bore Simons exhaust.

"Vizard worked on the head in the basement of his house in London. He did his head work using only hand tools except of course for shaving the head. This head with 11:1 CR put me at about 140 RWHP (standard flywheel HP was 95.) I’ve attached a picture of it here just prior to its most recent valve job. As you can see one cylinder had a leaking valve guide."

"The bottom half of the motor ran out of steam at around 940,000 miles. The head is still totally functional and in use 1.2 million miles later.
Somewhere in a box I have the paperwork. I can recall using race guides that were chamfered into the combustion chambers, the chambers being cc’d to be exactly the same as each other, the pushrod holes being opened to accommodate the roller rocker geometry, large satellite faced valves, and some other stuff I can’t remember having to do with swirl characteristics."

"Today this head is on a 2.3L B-20 stroker, same Webers, with direct port nitrous and water/methane, roller rockers and much much more."

I THINK MY BRAIN SURGERY HAS WIPED THE SLATE CLEAN HERE AS I REMEMBER NOTHING OF THIS.

DV

[BCjohnny]

I am certainly no expert, but I can't see much wrong with Erland's work, especially with the intake

If the material was there maybe the choke point could be moved back a touch ..... maybe not

Be nice to have a confirmation of the cuts .......

[williamsmotowerx]

SSR looked abrupt. I wasn't being disrespectful of your work, I was curious. There's usually a method to the madness.

This head was for a flow and dyno competition with a minimum chamber cc.
I believe the compression was only 11,5:1.
I do not want to mill the heads more than 3mm:s so I try to make the chambers as small as possible.
12,5:1 on our pump fuel is no problem, 16 bars on the compression tester.

To give an answer in the SSR I must know what you would like to change.
The reason it looks like it does is making an as gradual turn as possible without hitting water.

Erland

[Vintagewrench]

Vizard.jpg unnamed (2).jpg


A gentleman I met has this David Vizard modified 1.8L Volvo B18 pushrod head visible in the first photo which Vizard did for him 40-years ago in London, England. The second image shows a standard unmodified chamber.

I'm ready to start on another head, with a new chamber and port shape for next years vintage racing season with my own B-18 powered Volvo. My question is if this Vizard chamber shape would be a good model to pattern my new chamber shape.

Here is what he remembers about about the mods he had done to his engine: "I lived in Hackney back in the early 70’s and was torn between Ruddspeed and an upgrade to Volvo performance stuff from TAD in Finchley. Ended up with hi performance mods from TAD. But it was not overly impressive."

"So went next instead to local speed shop in Leytonstone where I became very good friends with the proprietor George Gur. He introduced me to David Vizard who built me a killer head. It went onto my B-18 bored to 2L and Derrington Motors in Reading supplied twin 40DCOE18 Webers with tri-y headers and large bore Simons exhaust.

"Vizard worked on the head in the basement of his house in London. He did his head work using only hand tools except of course for shaving the head. This head with 11:1 CR put me at about 140 RWHP (standard flywheel HP was 95.) I’ve attached a picture of it here just prior to its most recent valve job. As you can see one cylinder had a leaking valve guide."

"The bottom half of the motor ran out of steam at around 940,000 miles. The head is still totally functional and in use 1.2 million miles later.
Somewhere in a box I have the paperwork. I can recall using race guides that were chamfered into the combustion chambers, the chambers being cc’d to be exactly the same as each other, the pushrod holes being opened to accommodate the roller rocker geometry, large satellite faced valves, and some other stuff I can’t remember having to do with swirl characteristics."

"Today this head is on a 2.3L B-20 stroker, same Webers, with direct port nitrous and water/methane, roller rockers and much much more."

I THINK MY BRAIN SURGERY HAS WIPED THE SLATE CLEAN HERE AS I REMEMBER NOTHING OF THIS.

DV

David, Thanks for responding, even though you don't remember it, do you think that this shape would still work good today. Or would a more modern design be better.

[Erland Cox]

SSR looked abrupt. I wasn't being disrespectful of your work, I was curious. There's usually a method to the madness.

I have no problems with questions. Thinking about what we do is always good.
As you can see I let the port rise from the flange and at the highest part of the floor I almost do not touch.
Then I try to make the biggest radius possible without overhanging the valve seat on the SSR side.
This head was pretty good and the inly way to make the intake netter is by plugging the entrance and raising it.
A head like this flows 190 to 200CFM at 12mm:s and a raised head can flow up to 225CFM.
The exhaust looks worse than it is.
I had a Volvo 142 with a 2260cc engine 92 X 85mm:s bore and stroke.
It had a 46-38 head with the same intake and exhaust lobe.
Calculating in Pipemax the exhaust time area seemed high so I tried a 46-35 head.
I gained torque and lost no hp on top. 257Nm and 213 hp.
The exhaust will flow 150 CFM and that is more than enough for 200 intake CFM:s.
There are different heads. The B18 head has the valves closer together.
The early B20 head has an 89mm wide combustion chamber and a low exhaust floor.
The 73 and newer head has a 92mm combustion chamber and a higher exhaust floor.
I use the B18 ir early head for stock bores and the newer head for 92mm bores.

Here is an interesting Volvo project. Sadly Stefan passed away from pancreas Cancer: http://forum.savarturbo.se/viewtopic.php?t=24184

Erland

[jarmoyp]

http://forum.savarturbo.se/viewtopic.ph ... &start=285

Here is pictures of one Volvo B18 head, 43,4 mm/ 36,5 mm, moved valve centerlines. Dyno and flow chart founds too. 2.1 liter. 194hp, 232nm.