This Smug Mug picture program seems to work, so I put an extra set of pictures, building a fast road engine on.
You can enlarge the picture to see better details by clicking on them and in the top line take the sises you like.
Just have a look, and uh..... no racing engine secrets yet in these pictures.
http://sprint.smugmug.com/gallery/44547 ... #261934456
Hans
Engine pictures
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Mad Mart
- TDC Member
- Posts: 8535
- Joined: Tue Oct 03, 2006 5:48 pm
- Location: Winscombe, North Somerset, England
- Contact:
Re: Engine pictures
Thanks for showing us your photos again Hans, I was looking for them not long ago but couldn't find them. It's given me a couple of things to do to my track Sprint. 
Sprintless for the first time in 35+ years. 
... Still Sprintless.
Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S
... Still Sprintless.Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S
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shauniedawn
Re: Engine pictures
Interesting photo's - thanks for sharing them.
Just one question...
...for a road engine like the one you were building, what difference in combustion chamber volumes would you regard as acceptable in ml's please?
I do realise the ideal is to have them all identical - but in reality, what's 'near enough' - for example, within 0.5ml, 1ml, 5ml?
Cheers
Shaun
Just one question...
...for a road engine like the one you were building, what difference in combustion chamber volumes would you regard as acceptable in ml's please?
I do realise the ideal is to have them all identical - but in reality, what's 'near enough' - for example, within 0.5ml, 1ml, 5ml?
Cheers
Shaun
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Hans ten Broeke
Re: Engine pictures
Hi Shaun,
The problem with a 4 valve head is that there is just a very litle earea where you can take material away, because most of the surface are valves.
So my starting point is first clean the (totaly dissambled) head, we have a big glasblast cabinet, (carb restoring you know)
Check if the head is as flat as posible, because if a head need to be machined because he is badly warped, you will end up with combusting chamber 1 and 4 most of the time so much smaller that it will give far to much work to get them the same cise as number 2 and 3.
Now I check the valve seats if they are all at about the same hight into the chamber, (a 1/2mm lower valve has dramaticly much influance on the final cumbustion volume)
Take 4 new valves, and SU HD8 piston springs to close the valves, instal the type of plug I gone use in that engine.
Now I measur the 4 combustion chambers one by one with again these 4 new valves so at every measuring the same valve volume.
This give me the best sight if this head is for any good, or if the difference is already that big that it is uselles to try to get the chambers equal.
Because the amount of work of this part of a head is the same for a road or a race engine I also try not to go further than 0.5CC difference so 0.5ml (a bit over 1cc as a starting point)
You also name 5 ml you wont find such a head.
I hope you understand that it is very important to do all this (non costly) pre investigations (I'm not talking about the valve guides, cam bearing ext ext ext) befor the more expensive work begins, becouse at most of you that work has to be done at a machine shop, what I just discribet only cost time, a burette, the glass pipe with a glass tap at the bottom is less than €50 .
And in doubd just dont use that head, spending a fortune in it finding later out it went into the drain.
Hans
The problem with a 4 valve head is that there is just a very litle earea where you can take material away, because most of the surface are valves.
So my starting point is first clean the (totaly dissambled) head, we have a big glasblast cabinet, (carb restoring you know)
Check if the head is as flat as posible, because if a head need to be machined because he is badly warped, you will end up with combusting chamber 1 and 4 most of the time so much smaller that it will give far to much work to get them the same cise as number 2 and 3.
Now I check the valve seats if they are all at about the same hight into the chamber, (a 1/2mm lower valve has dramaticly much influance on the final cumbustion volume)
Take 4 new valves, and SU HD8 piston springs to close the valves, instal the type of plug I gone use in that engine.
Now I measur the 4 combustion chambers one by one with again these 4 new valves so at every measuring the same valve volume.
This give me the best sight if this head is for any good, or if the difference is already that big that it is uselles to try to get the chambers equal.
Because the amount of work of this part of a head is the same for a road or a race engine I also try not to go further than 0.5CC difference so 0.5ml (a bit over 1cc as a starting point)
You also name 5 ml you wont find such a head.
I hope you understand that it is very important to do all this (non costly) pre investigations (I'm not talking about the valve guides, cam bearing ext ext ext) befor the more expensive work begins, becouse at most of you that work has to be done at a machine shop, what I just discribet only cost time, a burette, the glass pipe with a glass tap at the bottom is less than €50 .
And in doubd just dont use that head, spending a fortune in it finding later out it went into the drain.
Hans
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shauniedawn
Re: Engine pictures
Evening Hans
That is really, really, interesting and informative. Like you say, it's very difficult to find room to take metal off easily in there - there's not much space.
When measuring my chamber volumes I had no data to go on - they were all within 0.5ml of each other, so I left alone, but that was just damage limitation approach!
I think next time I have the head off I will spend a little time and equalize properly though.
Whilst I've been typing this I've just had a thought - a daft one it may be...if faced with having to remove a substantial amount of metal to achieve a standard volume, how bad an idea is it to remove a slight amount from the face of the valve itself? Just had another thought...couldn't you just cut the seat a little deeper?
Again, I guess I know the answer(s) - you should leave the valves identical, and they should all really sit to the same depth in their respective seats.
Thanks for taking your valuable time to reply with a very comprehensive answer - I do appreciate it.
Kind regards
Shaun
That is really, really, interesting and informative. Like you say, it's very difficult to find room to take metal off easily in there - there's not much space.
When measuring my chamber volumes I had no data to go on - they were all within 0.5ml of each other, so I left alone, but that was just damage limitation approach!
I think next time I have the head off I will spend a little time and equalize properly though.
Whilst I've been typing this I've just had a thought - a daft one it may be...if faced with having to remove a substantial amount of metal to achieve a standard volume, how bad an idea is it to remove a slight amount from the face of the valve itself? Just had another thought...couldn't you just cut the seat a little deeper?
Again, I guess I know the answer(s) - you should leave the valves identical, and they should all really sit to the same depth in their respective seats.
Thanks for taking your valuable time to reply with a very comprehensive answer - I do appreciate it.
Kind regards
Shaun
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trackerjack
- Guest contributor
- Posts: 4727
- Joined: Fri Nov 23, 2007 11:33 pm
- Location: hampshire
Re: Engine pictures
Thank you Hans for sharing your knowledge, it is the knowledge of how that is the most important.
track action maniac.
The lunatic is out................heres Jonny!
The lunatic is out................heres Jonny!
