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Thoughts on this head/chamber work?

Thoughts on this head/chamber work?

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Discussion

Jhonno

Original Poster:

2,854 posts

63 months

Thursday 10th August
quotequote all
Thoughts on this chamber work?

Standard on the left, reworked on the right..

https://goo.gl/photos/K5U3Tpu4WAVXb18SA

227bhp

5,453 posts

50 months

Thursday 10th August
quotequote all
Looks a bit on the rough side, but does it perform? That is the question.

stevieturbo

12,636 posts

169 months

Thursday 10th August
quotequote all
What's the engine from ?

very peculiar shape for an OEM chamber, it would make you wonder why it is that shape.

PeterBurgess

546 posts

68 months

Friday 11th August
quotequote all
I would be interested to see photos of the underhead area of the inlet valves for both the original and welded heads?


Peter

Jhonno

Original Poster:

2,854 posts

63 months

Saturday 12th August
quotequote all
stevieturbo said:
What's the engine from ?

very peculiar shape for an OEM chamber, it would make you wonder why it is that shape.
TVR AJP V8

The most powerful 4.5 AJP I know of had chamber work too, but no images of what was done.
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Inline__engine

112 posts

58 months

Saturday 12th August
quotequote all
i think it is a much better improvment

Jhonno

Original Poster:

2,854 posts

63 months

Saturday 12th August
quotequote all
PeterBurgess said:
I would be interested to see photos of the underhead area of the inlet valves for both the original and welded heads?


Peter
This..?

https://goo.gl/photos/mJmNCufiGT2VZmAR8

https://goo.gl/photos/vQoyDtmib7UWAfYu5

Jhonno

Original Poster:

2,854 posts

63 months

Saturday 12th August
quotequote all
Inline__engine said:
i think it is a much better improvment
For what reasons?

Edited by Jhonno on Monday 14th August 08:08

Jhonno

Original Poster:

2,854 posts

63 months

Saturday 12th August
quotequote all
227bhp said:
Looks a bit on the rough side, but does it perform? That is the question.
The engine isn't up and running yet..

Mignon

216 posts

11 months

Saturday 12th August
quotequote all
It seems to be a massive amount of work for purposes I'm not quite sure about. A bit more squish area has been created and the two sides of the chamber have been separated by a ridge which maybe help to prevent inlet charge going straight out of the exhaust port at low rpm but could equally hurt scavenging at high rpm. I have no idea what the big lump welded into the inlet port is for. I see nothing in the welding work which will improve valve flow as the stock chamber has no valve shrouding other than just by the gasket fire ring which this work does not affect anyway. The spark plug now seems to be shrouded though unless a longer reach one is going to be used.

All rather bizarre IMO. The short answer though is that without doing just this work with no other mods you'll never have any idea what it achieved. If say you did everything else like valve seats, cams, induction, exhaust, tested all that and then put the chamber work in last before a second bhp test you'd have some idea but otherwise no.

PeterBurgess

546 posts

68 months

Saturday 12th August
quotequote all
Hiya
I meant the valve underhead area which I suppose is the 'back of the valve', interested as the new mods might well need an exciting shape to make the flow go where it is intended.
I tend to agree with Mignon, what looks poor on the original chamber is unshrouded and offers good combustion chamber characteristics, more so than the modded one. The modded one would have to rely on very superior flow to beat the original one overall. Is there a problem with achievable CR that the chamber vol needs reducing with welding?
Peter

Mignon

216 posts

11 months

Sunday 13th August
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Jhonno said:
The engine isn't up and running yet..
Perhaps you could tell us who is doing this strange stuff and why, or at least why they think they're doing it. It seems to me they're trying to copy shapes you tend to see in American V8 chambers but without actually understanding much of it. There was also a motorbike tuner on the web somewhere I came across a few years ago who had a thing about making inlet ports smaller but even he didn't just do it at the manifold end where it's of no purpose at all and actually counterproductive. If you want a blunt opinion everything you've shown us photos of so far is pointless and the inlet port thing is probably detrimental. Maybe the valve seat profiles are a bit better than stock but it didn't need the chambers welding to do that.

Chamber shape optimisation can do several things. Reduce valve shrouding, improve scavenging, increase squish, decrease burn time and hence the required ignition advance. The first doesn't apply here because there was no shrouding to start with. I see little reason to believe the second has altered much. There's a bit more squish area but there was loads to start with. There usually is plenty on 2 valve engines so adding more is a law of very rapidly diminishing returns. The final factor, burn time, alters if you can make the chamber much more compact. Even so you need to do some pretty radical stuff just to get a couple of percent more power. Although lots of weld went into these chambers most of it got ground back out again. I see no potential for much change in burn speed.

It seems the person is maybe trying to copy something like this from a Ford V8 race engine.

http://mooregoodink.com/new-powerful-kaase-boss-ni...

and a blow up of the chamber shapes here..

http://mooregoodink.com/wp-content/uploads/2009/05...

There's a huge problem though if that's the case. Let's see if anyone can spot it.

PeterBurgess

546 posts

68 months

Sunday 13th August
quotequote all
To be honest, I thought it was an enthusiastic home garage mod, except one can see flow bench etc behind. Usually one removes the inserts before welding for two reasons; the inserts can come loose with the heat required to TIG weld and secondly, and it does show, there is a large chance of porosities with welding next to and up to the insert.

Peter

eliot

7,663 posts

176 months

Sunday 13th August
quotequote all
Good point about pulling the seats out - it was the first thing my old man did before any head work like that.

227bhp

5,453 posts

50 months

Sunday 13th August
quotequote all
It looks like the seats have been replaced with Trojan alloy.
This is another one of those tiresome forum guessing games isn't it....

PeterBurgess

546 posts

68 months

Sunday 13th August
quotequote all
Interesting observation re inserts. If you look at the second pic he posts showing the modded chamber the inserts appear to overlap whereas in the original pic showing std and modded chambers the inserts do not overlap even on the finished modded chambers, does this mean the second pic isn't of the original modded chamber or is it the camera angle? Lots of questions and not necessarily playing guessing games?
PS how do you 'guess' it is Trojan alloy?
http://www.columbiametals.com/products/copper-allo...
Many folk use the inserts I have linked to below, but the use of berrylium is a little worrying being a heavy metal and the salts are not good for health especially if using a PEG type grinder for valve seat ops or sander bands for the modding of the throats.
http://www.performanceheadengineering.co.uk/servic...
A little off topic but the OP seems slow posting or adding any info.
Mignon, to me it looks a little reminiscent of Tony Knights work from Australia but Tony's work looks neater.
https://racemagazine.com.au/cars/incredible-datsun...
Peter

Jhonno

Original Poster:

2,854 posts

63 months

Monday 14th August
quotequote all
Sorry, not been online..

The engine is being built as a turbo'd lump, interesting you make the American V8 connection, as that is their main line of work, they are doing this as a side for someone.

Jhonno

Original Poster:

2,854 posts

63 months

Monday 14th August
quotequote all
227bhp said:
It looks like the seats have been replaced with Trojan alloy.
This is another one of those tiresome forum guessing games isn't it....
??

I'm not trying to create any sort of guessing game, I'm currently building my own AJP (N/A), which I was going to get headwork done on it, and came across this, and wondered the benefits if any for such drastic chamber modification. The most powerful 4.5 AJP I know of, had some chamber work, but no images of what was done.

Jhonno

Original Poster:

2,854 posts

63 months

Monday 14th August
quotequote all
PeterBurgess said:
Hiya
I meant the valve underhead area which I suppose is the 'back of the valve', interested as the new mods might well need an exciting shape to make the flow go where it is intended.
I tend to agree with Mignon, what looks poor on the original chamber is unshrouded and offers good combustion chamber characteristics, more so than the modded one. The modded one would have to rely on very superior flow to beat the original one overall. Is there a problem with achievable CR that the chamber vol needs reducing with welding?
Peter
I don't know if they have had CR issues, the engine is 10.5:1 as standard.

227bhp

5,453 posts

50 months

Monday 14th August
quotequote all
Jhonno said:
??

I'm not trying to create any sort of guessing game, I'm currently building my own AJP (N/A), which I was going to get headwork done on it, and came across this, and wondered the benefits if any for such drastic chamber modification. The most powerful 4.5 AJP I know of, had some chamber work, but no images of what was done.
Yet you have, you could have bundled all that into a properly worded question in the first place so instead of everyone asking questions, they could have been answering yours.