Head porting Tools Advice?

[Stueeee]

I had an extractor made up for doing heads,

My extractor is properly low tech. Seen here on a 1928 Chevrolet cylinder head I've been modifying. It's just a piece of steel tube with lug welded on. it's fitted to the port of whatever valve throat I'm working on. The hose of my workshop vacuum is plugged into the piece of steel tube. The clamped on steel ring is there to stop me running into the valve seat with the grindstone.

It's not clear in the photo above that I've already worked the top of the valve throats with a home made pilot cutter.

The valves I'm using are modern ones from some obscure Oldsmobile big block motor. They are the correct length (so that the valve geometry doesn't get boogered) but have slightly larger head and stem, and of course they're made from decent modern material.

 

[hotponyshoes]

My extractor is properly low tech. Seen here on a 1928 Chevrolet cylinder head I've been modifying. It's just a piece of steel tube with lug welded on. it's fitted to the port of whatever valve throat I'm working on. The hose of my workshop vacuum is plugged into the piece of steel tube. The clamped on steel ring is there to stop me running into the valve seat with the grindstone.
View attachment 385026
It's not clear in the photo above that I've already worked the top of the valve throats with a home made pilot cutter.

View attachment 385027
The valves I'm using are modern ones from some obscure Oldsmobile big block motor. They are the correct length (so that the valve geometry doesn't get boogered) but have slightly larger head and stem, and of course they're made from decent modern material.

I just stuck the manifolds back on when doing the chamber side and attached the hose to them with gaffa tape!

 

[Burdekin]

Any of you guys got a flow bench?

 

[hotponyshoes]

Any of you guys got a flow bench?

I haven't but I've seen a few home made ones before.
One using some of those carb-tune type things,
One using a clear length of perspex tube with a ball in, basically a big version of a tig flow gauge.
That one worked quite well, had a valve at one end so you could set the ball to the middle of the tube when you started. Chap used to stuff bluetack in places to see how it would mess with the flow.
Not sure how useful they actually are as the air will be flowing quite a bit quicker on a running engine (plus all the other things to account for like scavenging etc)

 

[minimutly]

I haven't but I've seen a few home made ones before.
One using some of those carb-tune type things,
One using a clear length of perspex tube with a ball in, basically a big version of a tig flow gauge.
That one worked quite well, had a valve at one end so you could set the ball to the middle of the tube when you started. Chap used to stuff bluetack in places to see how it would mess with the flow.
Not sure how useful they actually are as the air will be flowing quite a bit quicker on a running engine (plus all the other things to account for like scavenging etc)

I made one a few years ago. Couple of vacuum cleaner motors and an orifice plate. I’ve used a super flow one - that’s pretty much the same design. I’m on an American flowbench forum, they send you plans and provide bits if you need for a flowbench big enough to test Chevy V8s at 28 inches...

 

[8ob]

Any of you guys got a flow bench?

Got all the bits for one I will be building into an existing bench when the workshops cleared of mancave extension clutter.

It will run off a pair of these gurt vac pumps with a combo of ducts/valves so it can suck/blow. Takes a fair bit of airflow to make a decent flowbench.

.

 

[Pigeon_Droppings2]

On my Figaro nissan reduced the compression by dishing the pistons...i think it allowed them to slap a turbo onto their standard engine maybe.

 

[Burdekin]

I'm doing a Volvo B20, the exhaust has a very tight turn and floor is much too deep. The floor needs building up to get closer to matching the intake flow. There's plenty of horses to be had just getting exhaust to flow closer to the intake. Not doing that now but in future I want to have a play and experiment.

 

[minimutly]

I'm doing a Volvo B20, the exhaust has a very tight turn and floor is much too deep. The floor needs building up to get closer to matching the intake flow. There's plenty of horses to be had just getting exhaust to flow closer to the intake. Not doing that now but in future I want to have a play and experiment.

Good luck building up the floor of an exh. Port....

 

[Burdekin]

Good luck building up the floor of an exh. Port....

Yep realise the obvious issue being cast iron but folk have done it with good results so something I want to experiment with. I have a couple of ideas.

 

[MattF]

Good luck building up the floor of an exh. Port....

That's it. Don't over enthuse him with confidence. You negative sod.

 

[Dcal]

Is there a book or resource on modifying your type of head?
It's easy to mess up when you are starting out, so it might be as good idea to build on someone else's experience.
As the man said "at the cutting edge you bleed"

They can be cheap or expensive depnding on the model.

The books for the two engines I'm interested in were, I think, £150 for the Guy Croft Fiat Twin Cam one to a £5 for one on the Alfa Twin Spark.
Both are full of useful information

 

[Burdekin]

Is there a book or resource on modifying your type of head?
It's easy to mess up when you are starting out, so it might be as good idea to build on someone else's experience.
As the man said "at the cutting edge you bleed"

They can be cheap or expensive depnding on the model.

The books for the two engines I'm interested in were, I think, £150 for the Guy Croft Fiat Twin Cam one to a £5 for one on the Alfa Twin Spark.
Both are full of useful information

There isn't a book but a guy has done quite a comprehensive write up with pics and flow info on one of the forums. I'll check with the guy I bought the cam from first but if I do any porting it will be the restrictions just below valves.

 

[optima21]

Any of you guys got a flow bench?

I did a simple DIY one using a wet/dry vacuum cleaner, waste plumbing pipe and pitot tubes for calculating the air speed.........Im not sure what happened to the pictures though

£15 flowbench and DIY headwork

I know some people have big budgets for their cars, and mine is pretty small, but for me its about the challenge of doing something and following my ideas, rather than having people telling me I cant do what I want to. So when I decided that I wanted to port a cylinder head for my polo, I...

www.mig-welding.co.uk

I'll have a look tonight if I can find copies of the pics.

 

[Burdekin]

I did a simple DIY one using a wet/dry vacuum cleaner, waste plumbing pipe and pitot tubes for calculating the air speed.........Im not sure what happened to the pictures though

£15 flowbench and DIY headwork

I know some people have big budgets for their cars, and mine is pretty small, but for me its about the challenge of doing something and following my ideas, rather than having people telling me I cant do what I want to. So when I decided that I wanted to port a cylinder head for my polo, I...

www.mig-welding.co.uk

I'll have a look tonight if I can find copies of the pics.

Pics would be great thanks. Don't think I need a calibrated flowbench, just one to compare ports.

 

[cr500dom]

Good luck building up the floor of an exh. Port....

Devcon epoxy putty works fine for that even on turbo motors

 

[minimutly]

That's it. Don't over enthuse him with confidence. You negative sod.

Well, if it was the inlet port I’d be all ears. Getting any sort of filler to stay in place in the exhaust is fraught with issues. Strangely, carbon seems to do well in there, at least while the engine is used regularly.

 

[8ob]

Pics would be great thanks. Don't think I need a calibrated flowbench, just one to compare ports.

Its useful to know the flow numbers at various degrees of valve lift, as in there is no point in lifting a valve any further past the point flow doesn’t increase, this saps power. Helps to make a calculated cam choice.

Bob

 

[Burdekin]

Its useful to know the flow numbers at various degrees of valve lift, as in there is no point in lifting a valve any further past the point flow doesn’t increase, this saps power. Helps to make a calculated cam choice.

Bob

Yeah, I just meant having it calibrated at 28 inches etc. I don't know if the home made ones can do all of that.

But yeah testing valve lift flow to determine where flow stops with valve lift and gets worse would be something I would do. I'm however not chasing max hp but important not to put a cam in with too much lift.

I don't have the numbers but I think the exhaust flow would be really poor compared to the exhaust. In my head I think that is where there is a lot of power to be made matching intake and exhaust. It might be something like 65% at a guess.

 

[Burdekin]

Well, if it was the inlet port I’d be all ears. Getting any sort of filler to stay in place in the exhaust is fraught with issues. Strangely, carbon seems to do well in there, at least while the engine is used regularly.

I was thinking plates fitted in and then shaped might be the best approach. But I haven't tried this before so all a learning curve.