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Still some questions re. Head porting


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Thanks a lot for the good advice

Yes I know air driven is better, but I have only a small 220V compressor and currently no place for a bigger one & no 3 phase current in the garage, required for the real stuff

The device from Lidl Germany is not shipped abroad, but it's a real bargain.

I was in a local shop but didn't find tungsten carbide burrs. Do you buy it online or in a local tool shop?

I bought some grind stones with 3mm shaft, that I will try in my 130W beefed up Dremel kind tool.

Let's see how long it takes until I get fed up and buy the Makita or find a German comuter work-mate, who's willing to receive the shipping from Lidl.

@ Frederic

you were quoting the preparation instructions for the triumph 1500 engine from the P. Burgess' book, which I've learned by heart by the way....

Yes I agree, it's not too precise.... It states also " The chamber wall on the spark plug side of the head needs to have the chamfer removed to create a straight line from the head face to the original wall starting point in the chamber roof."

I thought the way to go here was to  "smoothen the ridges l. & r. of the plug hole"

Removing all material in a straight line from edge to edge is a lot of material, and needs to be compensated when shaving the head... Do you "smoothen" or "straight-line" around the plug-hole?

Thanks for the link on triumphexp. didn't know that one. 3 pages including "GT-bonus" :) ...  I'll have a beer and chips to fully enjoy the read

Cheers

Patrick

 

 

 

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Hello All

             I agree with Nick those are a rip off.

I bought a set off Fleabay listed as tungsten and have done a 4 & 6 cylinder head and they still seem ok.

I have an old motor fixed above the bench and use a flexible drive shaft not fast and no good for stones but ok for burrs and I use small flap wheels (Fleabay again)

But there is no rush and it is better to take your time as you can not put metal back on!

I have to disagree the more pointed burrs do reach into odd corners!

Roger

 

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How do you guys deal with the mess? It was horrendous when I last did some porting, and put me off doing it in the garage as I hate the idea of residual bits of swarf potentially lurking where I might need a clinically clean environment for building the engine back up again.

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RB, One way might be to rig a vacuum cleaner to the other end of the port as you work. 

Escadrille, mentioned that a burr at 2-3000rpm was hard work.  Quite the reverse at 12,000 on an air tool!   A light touch is needed, as it will remove metal very easily!

John

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5 hours ago, JohnD said:

RB, One way might be to rig a vacuum cleaner to the other end of the port as you work. 

Escadrille, mentioned that a burr at 2-3000rpm was hard work.  Quite the reverse at 12,000 on an air tool!   A light touch is needed, as it will remove metal very easily!

John

The really hard part about using the drill is that it's bloody heavy although I'm built like a cyclist not a weight lifter :biggrin:

However the one good thing with it is that the swarf is fairly large and doesn't travel too far. I put up a couple of bits of hardboard either side of the job to keep the the crap fairly well contained.

Like John says a vacuum cleaner (or in my case the old Vax) rigged up by the piece helps enormously. Just adds a bit more to the aural cacophony!

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Another top is always to wear gloves.  Vinyl ones better than latex, and they prevent you getting a dozen needle sharp fragments in your hands' skin.   Even if they don't fester, they'll stick I to you, or at best rust away over the next week, until the new skin grows!

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Looks like the Belgian Lidl shop also has the die grinder and will allow you to purchase it.
Though they don't send it abroad so you will have to have it send to a pick up point in Belgium.
https://www.lidl-shop.be/nl-BE/PARKSIDE-Rechte-slijpmachine-PGS-500-A1-500-W/p100312246

+1 for the vacuum cleaner

As for gloves, I like nitrile ones as the latex can cause allergies in the long run.

I also tried stones on the drill, amazing how fast they wear when you don't spin them fast enough.

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Here are 8 questions with pictures with red arrow to show the point of interest:

1) INLET THROAT:  border from machined to cast surface on LSR - Instructions say don't machin LSR, but rough material is sticking out ref.to machined part below valve seat.   Leave  or clean up, with the risk of reducing Ventury effect?

IMG_9463.jpg.17452fcf1366787d7a284906cb613c3b.jpg

 

2) INLET THROAT: Transition from SSR to LSR

If this ridge is removed, will it have a positive effect on flow, or will it generate a negative effect, as it increases cross section  --> reduces speed and Ventury?

 

IMG_9464.jpg.474db0028abd3154bcc2e653d504d670.jpg

 

3) INLET GUIDE BOSS: P. Burgess book says to remove it. But it's  nothing but a sharp edge, making the transition from LSR to valve guide. Did you remove it ?   

 

IMG_9465.jpg.ebf5fa5253f08b7a311af370c4879f5a.jpg

 

 

4) CHAMBER RIDGE NEXT TO SPARK: smoothen out or straight  line from corner "chamber roof" to corner "cylinder head surface"? That would be a lot of material in the 2nd case...

IMG_9466.jpg.65a981834c0036aa3c913d1b8557d6ce.jpg

 

 

5) SSR INLET: Don't know how to use the 3 template cross sections from the 6-Cylinder from this forum, as the 6 cylinder throat is less shallow.

I will be using this 2,5 mm depth gauge to measure a first cut with the burr at the ridge "end of throat" at 45° in order to make a smooth SSR into the runner.  THen I intend to smoothen out from this 2,5mm cut.    Would that make sense?

IMG_9474.jpg.0fecb9f7af2dee0fc2807ca558b618cc.jpg

 

6) SSR EXHAUST: Shouldn't I smoothen out this rdge a bit? It looks so counter intuitive to have this sharp edge in the SSR, even if exhaust is pressed out under high pressure...

 

IMG_9468.jpg.d2fafc4f85295ee5881e27e0d568b1cd.jpg

 

7) EXHAUST PORT HUMP: This hump at the bottom is reducing the cross section, as the ceiling is not getting higher by the same amount. I leave it as as?

IMG_9469.jpg.7f2c12c6f984493a8ae33ad415b28be3.jpg

 

8) FIT MANIFOLD - HEAD:  The 2 pictures below show the gasket holes are almost 4mm bigger than the holes of the manifold and the port.  The fit of the manifold to the port is rather good. I'can't feel any ridge, when probing with a scribe. So I leave everything as is and won't increase the diameter of manifold runners  and ports, just to match the gasket?   (I'm just talking about the matches of the holes, of course I will smoothen out the step 1cm inward of the  the inlet-port )

IMG_9471.jpg.38f3305c84b026782b46543af4c5980a.jpg

IMG_9470.jpg.34b56348f2a194d332dc69c0e80f6f14.jpg

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1, 2,3, 5&6 are relics of the inadequacy of production techniques.    Smooth out.

4, see the Vizard diagram.    Smooth.

7, smooth, but you're working on a four cylinder head?   Is there water behind that?   I don't know.

8.  Match the diameters.

I regret that when I copied Vizard's T&P book, that included schemes for T4s, I only took the T6 details.   But here's his 'idealised' inlet duct.     You'll note the expansion under the valve.   He suggests that this should be 0.97 times the valve diameter, when the stright section should be 0.84 time that.    The tapered section should have an included angle of between 4 and 8 degrees.

 

Vizard idealised inlet.jpg

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Patrick,

You've got me thinking, which in many cases is quite dangerous. However, I have slowly over the last few years collated a collection of tuning articles etc, however they are scattered around mutliple harddrives and computers!

First up, some Vizard advice that may be of use. This may the same as his book, however I think I gained this from another article?

Cylinder Head Porting - Head Porting Basics by David Vizard.pdf

And a pdf of Neil Collingwood's DIY thread, this may already be elsewhere on sideways, but as I found it I shall post it!

48722741-DIY-Head-Modification.pdf

I think I may have more, however if I do it will be on my PC, and that desk is currently occupied by SWMBO doing her "working from home" malarky, so that will come later.

HTH,

Phil

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John has covered the basics of your questions, I'll add my thoughts here as well:

2 hours ago, roulli said:

1) INLET THROAT:  border from machined to cast surface on LSR - Instructions say don't machin LSR, but rough material is sticking out ref.to machined part below valve seat.   Leave  or clean up, with the risk of reducing Ventury effect?

IMG_9463.jpg.17452fcf1366787d7a284906cb613c3b.jpg

 

2) INLET THROAT: Transition from SSR to LSR

If this ridge is removed, will it have a positive effect on flow, or will it generate a negative effect, as it increases cross section  --> reduces speed and Ventury?

 

IMG_9464.jpg.474db0028abd3154bcc2e653d504d670.jpg

As John has said, smooth them out.

2 hours ago, roulli said:

3) INLET GUIDE BOSS: P. Burgess book says to remove it. But it's  nothing but a sharp edge, making the transition from LSR to valve guide. Did you remove it ?   

 

IMG_9465.jpg.ebf5fa5253f08b7a311af370c4879f5a.jpg

You can smooth it out if you wish, but I seem to recall that it makes minimal difference.

2 hours ago, roulli said:

4) CHAMBER RIDGE NEXT TO SPARK: smoothen out or straight  line from corner "chamber roof" to corner "cylinder head surface"? That would be a lot of material in the 2nd case...

IMG_9466.jpg.65a981834c0036aa3c913d1b8557d6ce.jpg

I never did much with this bit, but smoothing it out at least makes sense. Just be aware that this will decrease CR slightly, so do any CR calcs/measurements after, and ensure all Comb Chambers are the same.

2 hours ago, roulli said:

5) SSR INLET: Don't know how to use the 3 template cross sections from the 6-Cylinder from this forum, as the 6 cylinder throat is less shallow.

I will be using this 2,5 mm depth gauge to measure a first cut with the burr at the ridge "end of throat" at 45° in order to make a smooth SSR into the runner.  THen I intend to smoothen out from this 2,5mm cut.    Would that make sense?

IMG_9474.jpg.0fecb9f7af2dee0fc2807ca558b618cc.jpg

IIRC, you want the depth to be set at roughly the middle of the SSR. I can't recall if I used 2mm or 2.5mm however, though I think that there is enough meet for the deeper cut?

Exhaust stuff, yeah I would smooth these out, but not reshape so much, if that makes sense?

Manifold ports - as John says match the inlet ports on both sides.

Phil

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Thanks a lot John and Phil,

Waiting for the burrs and flappers...

Pressed out the old guides and did already 2 ports with a flame-shaped stone in the Dremel type tool. Worked quite well..

I prefer to take a bit more time, and check more often, as I don't see so well. So I don't want the tool to be too performant...

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2 hours ago, roulli said:

I prefer to take a bit more time, and check more often, as I don't see so well. So I don't want the tool to be too performant...

Indeed, as I said earlier on, if you have the time and the patience and haven't done this much before - a slower tool gives time to think and reduces the risk of something bad happening!

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