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Re: Head work..
#247470
28/11/2006 01:54
28/11/2006 01:54
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Anonymous
Unregistered
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Anonymous
Unregistered
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its already been started buy another mechanic unfortunately otherwise i wouyld have considered it... ive done the engine in and out job myself before, im just so busy these days if i started it again, it would never see the road again. Iain
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Re: Head work..
#247471
28/11/2006 01:58
28/11/2006 01:58
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Anonymous
Unregistered
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Anonymous
Unregistered
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Will barabz not give you some money back if you ship yours over as they go for good money a decent head and block?
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Re: Head work..
#247472
28/11/2006 02:01
28/11/2006 02:01
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Anonymous
Unregistered
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Anonymous
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i dont know, bound to be worth a try... My block isnt knackered im told and the head would be used as an exchnage for the re-worked one i suppose. Bloody engine only had 30k on it too
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Re: Head work..
#247473
28/11/2006 02:02
28/11/2006 02:02
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Anonymous
Unregistered
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Anonymous
Unregistered
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Prob be ok with new pistons or rings then. whats gone on it? take it the ringlands have failed or holed piston?
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Re: Head work..
#247474
28/11/2006 02:02
28/11/2006 02:02
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Anonymous
Unregistered
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Anonymous
Unregistered
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I was just siiting here thinking exactly that.
Stick the car on a trailer and take it across on the boat.
What is it these days - £110 return?
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Re: Head work..
#247475
28/11/2006 02:04
28/11/2006 02:04
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Anonymous
Unregistered
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Anonymous
Unregistered
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yeah £110 from Larne to stranraer...
But then 425miles towing the coupe behind the pickup and the same home again... would be more simple to just pull the engine out...
Iain
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Re: Head work..
#247476
28/11/2006 02:11
28/11/2006 02:11
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Anonymous
Unregistered
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Anonymous
Unregistered
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Veggie tank would be a good option adn get the sleeper to liverpool as well can be quite cheap and with barabz youd prob have to book far enough in advance to get a cheap one and just get a student friend to book it as well
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Re: Head work..
#247477
28/11/2006 02:14
28/11/2006 02:14
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Anonymous
Unregistered
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Anonymous
Unregistered
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Who is barabz??
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Re: Head work..
#247478
28/11/2006 02:19
28/11/2006 02:19
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Anonymous
Unregistered
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Anonymous
Unregistered
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Better option to get the engine sent over then. Ask him about exchange on your old one. That means that you get everything constructed by barbz and you only need to re-assembled it back into your car.
Ross
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Re: Head work..
#247479
28/11/2006 05:31
28/11/2006 05:31
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Joined: Dec 2005
Posts: 12,295 Sandhurst
Begbie
Ex El Presidente
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Ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,295
Sandhurst
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Guy Croft all the way for head work.
I will post more tomorrow as to why, after being at Guy's workshop today, but silverstone, 8 hours of driving today and some bad news with some of my engine parts means i knackered!!
Your car is Usain Bolt with wellies
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Re: Head work..
#247480
11/12/2006 21:44
11/12/2006 21:44
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Joined: Dec 2005
Posts: 12,295 Sandhurst
Begbie
Ex El Presidente
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Ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,295
Sandhurst
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So a little later than expected...
Headwork should really be carried out by someone who knows what they are doing, but who also has access to a flow bench.
The above factors are as important as each other, because if someone doesn't know what they are doing, they will end up taking too much material off and will hit a water / oil gallery, which would make your head dead.
The flow bench is also equally important, as how do you know the work that is being done, is actually yeilding improvements, when it could actually make it worse? Then how do you know that the work that has been done to one set of ports, be exactly the same on the rest? You can not match the same results by eye alone.
Final point, how do you know that the work has been done, is actually flowing the air correctly into the cylinder?
With a flow bench, you have facts and figures and help work things out, but no figures could mean good head work or could mean bad headwork, with no 2 results being the same on each cylinder
Your car is Usain Bolt with wellies
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Re: Head work..
#247481
11/12/2006 21:48
11/12/2006 21:48
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
So a little later than expected...
Headwork should really be carried out by someone who knows what they are doing, but who also has access to a flow bench.
The above factors are as important as each other, because if someone doesn't know what they are doing, they will end up taking too much material off and will hit a water / oil gallery, which would make your head dead.
The flow bench is also equally important, as how do you know the work that is being done, is actually yeilding improvements, when it could actually make it worse? Then how do you know that the work that has been done to one set of ports, be exactly the same on the rest? You can not match the same results by eye alone.
Final point, how do you know that the work has been done, is actually flowing the air correctly into the cylinder?
With a flow bench, you have facts and figures and help work things out, but no figures could mean good head work or could mean bad headwork, with no 2 results being the same on each cylinder
but surely there are other people who know what they are doing and have access to a flow bench Are these not criteria to keep in mind before letting someone near your head rather than a reason why you should use one person in particular?
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Re: Head work..
#247482
11/12/2006 22:03
11/12/2006 22:03
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Joined: Dec 2005
Posts: 12,295 Sandhurst
Begbie
Ex El Presidente
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Ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,295
Sandhurst
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Yes, there are, one of them is Guy Croft who did my head work.
But what about everyone else? People can post i have full race head work done, but no figures to go with it. So how can it be classed as head work when there are no figures to go with it, or even porting work, how do you know it has been done exactly the same across all 4 / 5 cylinders. 1mm here or there can have a huge effect on your airflow and the results you get!
You cant know these things without a flowbench, which is seems, no one has!
Your car is Usain Bolt with wellies
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Re: Head work..
#247486
11/12/2006 23:11
11/12/2006 23:11
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Anonymous
Unregistered
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Anonymous
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slightly off topic and out of curiosity: are flow benches a great investment for an engine builder? I mean we are talking 1000quid, or 10000quid?
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Re: Head work..
#247487
11/12/2006 23:20
11/12/2006 23:20
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Anonymous
Unregistered
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Anonymous
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Power Rog!What ever happened to your fantastic Power headwork you was offering a while back with flow charts and all?
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Re: Head work..
#247488
12/12/2006 00:16
12/12/2006 00:16
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Joined: Dec 2005
Posts: 3,158 Near Reading
JohnS
I need some sleep
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I need some sleep
Joined: Dec 2005
Posts: 3,158
Near Reading
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Quote:
but i believe that a 10% increase in flow through the head will give a 10% increase in power.
That's just not true, otherwise you would make the ports as large as you possibly could.
It isn't just to do with the physical CMM/CFM it's also to do with the flow characteristics, which is why my high flowing Scholar head was a bag of sh**e. The flowbench report looked good though if that's any consolation. There;s a lot more to port work than the increase in flow.
As an example, more flow can also mean more loss of gas energy so worse spoolup and worse top end as the gasses lose energy down the port and slow down/stack up. In the case of my old head the only way it would work better than a stock head in the real world would've been at 7500+rpm and 2 bar boost probably.
And that is all because a flow bench is a testing tool under a steady state (constant temps/pressures etc)whereas an engine exhibits huge pressure differentials across the 4 stroke cycle and wide differences in waves of energy. Furthermore a flowbench does not measure the large effect in exhaust porting of temperature drop which has a much larger overall effect on the flow of gasses out of the exhaust ports than the volume of static flow of the ports themselves. How can you model gas flow at room temperature or any static temperature/pressure when in an engine the gas temps and pressuresare all over the shop in the exhaust ports, and also changing rapidly.
Headwork has to be matched to the characteristics of the engine in a dynamic environment, the effect of the cam profile and the characteristics of the turbo (in our case). There is nothing on a flow bench that can reflect the majority of the important overall factors - eg. variable cylinder pressure, variable port pressure, variable temperature, variable acceleration and deceleration of air/gasses, variable waves of pressure etc. as primarily a flow bench is a static pressure. Therefore without practical knowledge of a particular setups characteristics it is a flawed academic exercise. In fact I would say it is worse than an academic exercise - you're effectively trying to approximate a two or three dimensional solution to a ten dimensional problem.
In my opinion the only value a flowbench has is an easy way to check tolerances of work carried out on heads to a well known and tested port design.
Lets suppose your standard head is a moss bros suit. You can either buy a lovely Armani suit with your size in the label without trying it on or really knowing what you will look like in it, or you can buy a tailored suit that has been measured up to you to the Nth detail and you know how it will fit and what it will look like on you
I would liken the Armani suit to a head done by someone who has a flowbench but has no particular engine specific knowledge and liken the tailored suit to someone who has engine specific knowledge. You pays your money, you takes your choice.
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Re: Head work..
#247489
12/12/2006 00:42
12/12/2006 00:42
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Joined: Dec 2005
Posts: 12,295 Sandhurst
Begbie
Ex El Presidente
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Ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,295
Sandhurst
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John, re-read the first 3 words of what you quoted me on, I didnt say it was fact, it was I thought was correct, obviously not
Your car is Usain Bolt with wellies
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Re: Head work..
#247491
12/12/2006 01:34
12/12/2006 01:34
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Anonymous
Unregistered
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Anonymous
Unregistered
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Well said John!
My thoughts exactly
Beggars!I dont think its fair on others who are interested in this Tuning area, by giving out misunderstood theories without any solid evidence & experience to back it up. There are many firms which offer flowbenched headwork thats not all what its cranked up to be, but i believe its a simple case of all the gear but no idea.
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Re: Head work..
#247493
12/12/2006 02:15
12/12/2006 02:15
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Joined: Dec 2005
Posts: 2,588 Essex
Rog20VT
I need some sleep
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I need some sleep
Joined: Dec 2005
Posts: 2,588
Essex
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Quote:
Power Rog!What ever happened to your fantastic Power headwork you was offering a while back with flow charts and all?
and who are you (somebody we all know )
closely following my progress are you?
no rest for the wicked!
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Re: Head work..
#247494
12/12/2006 02:31
12/12/2006 02:31
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Anonymous
Unregistered
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Anonymous
Unregistered
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Ok, Here goes, www.torqueitalia.com, no theories but reality. I think at this level of tuning its not just a simple case of chipping in, thats why you are using Guy Croft to do your potential race engine. Little bit of a contradiction here.
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Re: Head work..
#247495
12/12/2006 02:43
12/12/2006 02:43
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Anonymous
Unregistered
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Anonymous
Unregistered
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Hi Barbz whats with the name change to Bobby Shay
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Re: Head work..
#247496
12/12/2006 02:51
12/12/2006 02:51
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Anonymous
Unregistered
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Anonymous
Unregistered
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Wot you ona about mate, another joker given out misleading information.
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Re: Head work..
#247497
12/12/2006 02:55
12/12/2006 02:55
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Anonymous
Unregistered
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Anonymous
Unregistered
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Try this, start at the bottom and read up the list, it will pretty much tell you what you need to know, very interesting and better then many of the books I purchased, well except for one. http://www.guy-croft.com/viewforum.php?f=2rich
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Re: Head work..
#247498
12/12/2006 03:42
12/12/2006 03:42
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Anonymous
Unregistered
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Anonymous
Unregistered
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Lol @ Saracen
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Re: Head work..
#247499
12/12/2006 16:10
12/12/2006 16:10
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
not really sure how someone can consider themselves a performance engine builder without one
Have to disagree, we have never needed to use one to get the results we need.
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