Self build flow bench

Road-race engines and ancillaries - general discussion
FLY205

Self build flow bench

Post by FLY205 »

Following some internet idication sourced from an australian link,I build this Flow bench. I haven't lots of depression, maybe my industrial vacuum cleaner doesen't supply the right suction.

Below the picture of the bench.
any suggestion Welcome!!!

Future plan:
-increase vacuum using garden blower
-finding a cheap seat cutter ( where ???? )

thanks
Flavio
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Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

Well done for 'having a go'!

There is a recent thread worth reading in GC Q&A on this too,

GC
WhizzMan
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Re: Self build flow bench

Post by WhizzMan »

This looks like a promising setup.

I wouldn't trust the leaf blowers I see in the shops here for being very consistent. How are the blowers where you live? Myself, I'd try and get some more shop vacs and put them parallel. From what I've seen on Internet about DIY flow bench building, you'll need multiple kilowatts for good flow and depression. Maybe others with good flow benches can tell how much power their motors have?

I read your remark about finding a "cheap seat cutter". I think it's safe to say none of us wants to pay too much for good tools, but nobody wants to work with inferior tools, no matter how little they cost. I'm looking for a good seat cutter set myself and find that it's just not possible to get good quality for bargain prices. Especially when it comes to things like seat cutters, you can't really substitute quality with spending a bit more time or the odd extra curse word, to get the result you're after. You are doing that with your flow bench, which is probably a very suitable project/tool to save money by doing it yourself.

I'm looking for a set of cutters myself and have concluded that it's probably best, to just buy the cutters I need for each job when it comes along. That way, you won't have to buy all sizes in the angles you think you'll ever be needing, but just the 3 or maybe four sizes required for your first project. The next project, you may be able to re-use some, or all of them. I've seen decent starter kits of non-specialized brands around the 400 Euro mark. Getting separate Neway cutters will probably cost you something similar for your first project. Maybe people here will have advice on what other brands and models are good value for money?
Book #348
Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

"I think it's safe to say none of us wants to pay too much for good tools, but nobody wants to work with inferior tools, no matter how little they cost".

MODEL POST!

Well said Homme!

You mentioned Neway and yes they are good and likely the lowest-cost choice (not to say that they don'tcost 'a few bob' - they do) but much depends on the state of the guides. Worn guides will likely need their expanding pilot which just doesn't offer the same standard of concentricity as their precision ground tapered ones - and indeed could not given that on well-worn guides there isn't a straight line in them.

G
FLY205

Re: Self build flow bench

Post by FLY205 »

Hy Friends!
Yesterday night at 2:00 am..
Self build seat cutter using a small lathe, a dremel, metal hand saw, and a small drill...
Last edited by FLY205 on September 5th, 2011, 11:20 am, edited 1 time in total.
Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

Can you please replace your photos with some of good quality and not so massive?

Thanks,

G
FLY205

Re: Self build flow bench

Post by FLY205 »

Ok, no problem.
I would like to cancel the last two photos but i can't understand how.
Thanks
Flavio
Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

Just log in and click on 'edit' and scroll down to the control box for attachments - you should be able to delete there.

If you have problems I can do no worries,

G
FLY205

Re: Self build flow bench

Post by FLY205 »

Job done,
thank you Guy.
Please wait for better pictures.
Flavio
Simon
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Re: Self build flow bench

Post by Simon »

This is a great thread Flavio, and I will be following it with interest. I started a similar project some time ago to do some work on my Crossfire heads d=following a visit to GCRE. I was using a similar design but based on a garden blower as they appeared to be the cheapest way of buying something that could move large volumes of air. But I was also struggling to pull enough vacuum and so added another blower. This improved things a lot but I think the efficiency of the fans/housings in the leaf blowers isn't brilliant so need to sort that out. I shelved the project to work on the Spider but this has sparked my interest again. A word of warning though if you are thinking of going the leaf blower route - they are very noisy, especially when bolted to what amounts to a big sounding box - I'm sure the neighbours thought I was running up a jet fighter in the garage! If anyone is interested I can post up the build pictures, but in another thread so as not to dilute this one.
GC_15
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Re: Self build flow bench

Post by Guy Croft »

This subject has been mentioned a number of times here, I should prefer that any member engaged in making their own bench post on this thread to consolidate the information.

Thanks,

GC
SirYun
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Re: Self build flow bench

Post by SirYun »

Hi,

I have my flowbench setup up and running.
It is a very simple setup and I can take it apart and store it when i'm not using it.

It uses an audie flowquik ( averaging pitot tube), and old laptop (free from a friend) and a test plenum made from 125mm sewage pipe.
motorbox, audietech, flow quik and
motorbox, audietech, flow quik and
motorbox-+-computer.jpg (16.4 KiB) Viewed 10618 times
The motorbox is a simple two chamber cube housing two 220v motors 1200watt (Ametek-Lamb 115519, 2 stage ,periferal discharge and normaly used in professional scrubbing machines, unlike cheap vacuum motors these will cool themselves even at low flow high depression and due to the larger rotor will move more air at a higher depression). Maximum practical flow is about 180 CFM (cubic feet per minute) at low depression , or about 145 cfm @21 inch maximum .
Depression at low lift is quite a bit higher and actualy goes off the scale of the flowquick (so >55 inch).

becaue i only deal with small engines (maximum 1500cc) i did not feel like i had to have huge air moving capabilities as i would doubt i will need more than 200 CFM .

On the subject of vacuum source: leafblowers can move a lot of air but at very low pressure. NOT what you need for flowtesting. Although in theory it should still work as you only need about 1 mm of depression for the flow to remain turbulent (limitations apply for very low valve lifts though) within a port.

Vacuum cleaner motors can pull more vacuum but the combination of high CFM and high vacuum is not easy. if you combine several different motors ( for instance salvaged from various vacuum cleaners) in one cabinet keep in mind that the one with the least amount of depression and flow will limit the capabilities for the entire cluster.

Picture is a 1,5 inch plate orifice pullling max depression (21.12') and the CFM value converted to 10 inch depression. The calculated flow for an orifice this size is about 97 CFM (I say about as it depends on quite a few factors , most notably the Cd of coefficient of discharge, if you change that by 0.001 the calculated flow wil go up 0.1 CFM so rather than try to achieve a theoretical measurement accuracy, it is better to know the limits of your method)


The audie way of compensating for depression is actually quite effective and will work for several inches +/- although i try to keep the depression within about 0.5 inch to keep effects to a minimum. taking readings is very fast and it you can set lifts fast i think that you can test at about lift 30 positions within 15 minutes without much problems. My only complaint is that it would have been very nice to be able to export to excel as i find that a lot easier for making graphs that make sense. That said, it does graph pretty much everything you can think of, and once you get past the not very intuitive user interface you can test very quikly and with a high degree of repeatability (the claimed 1% seems achievable).

if you want to test by blowing though (for exhausts) the box is simply turned around and re-attached. No leaking valves, no moving parts. However,I will be testing the exhausts by applying vacuum at the exhaust side and adding a bore adapter sideways. This eliminates the problems that this unit has when flowing reverse (you have to recalibrate it otherwise it will read wrong) and the warmer vacuum motor exhaust air will affect the measurements as well.

add: not suprisingly the exhaust flow of the box has an effect of the performance of the vacuum motors. I my case i think i will have to make an additional ''decompresion'' hole that can be simply opened when not using blow though.


I build a very simple motor controller using a ready build Phase controller from Kemo and added a extra ten turn potentio meter (from my ''ex lab junk'' box) so it can quite precisely control vacuum motors to a maximum of 4000 Va (or 16 amps at 220v) and these motors only draw about 10.6 Ah combined at full pull.

housing is made from a piece of 125mm pvc pipe coupling and the total cost including everything is less than 50 euro's
simple and cheap motor controller.
simple and cheap motor controller.
controller.jpg (18.23 KiB) Viewed 10618 times
.

end result is very useable.

While this is a relatively low cost solution ( i think around 500 euro total including two new vacuum motors), there are ways to make a flow tester for 1/4 of the cost with a load of PVC pipe, an orifice and a few pieces of flexible tubing. ( and a piece of paper to do the calculations)

A medium size single shop vac will work, a single normal one not quite so good although you only need a very low depression to get meaningfull results (despite of what many state and claim that 28 inches or more are needed..).


A simple google search will lead to a entire forum dedicated to the construction of these things including some very impressive constructions using eaton and paxton blowers coupled to a large electric motor and fully computerised and automated
Last edited by SirYun on September 15th, 2011, 7:06 pm, edited 1 time in total.
Joost M. Riphagen
Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

MODEL POST!

Good to see you again Joost! Thank you very much for taking time to write & illustrate your post in unacceptable technical style - very informative and very useful.

G
4v6
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Re: Self build flow bench

Post by 4v6 »

At the heart of my own flowtester, like Joost, I also utilise the AudieTech "Flowquick" tester.

I've had mine since 2007 and it's been nothing but a boon, very fast to get measurements and very repeatable.
Although it's not as stable as the Superflow bench would be so it makes evaluating seat alterations harder, but on the whole for what it cost it's a fine little instrument.

Here's a photo of my current setup.
At the base is the plenum/damper, made from heavy gauge marine ply, glued and screwed to stop it getting blown apart and on which mounts the adaptor for the heads to sit on.
I fitted a steel plate to the top to make it more rugged and to take the fixings for the head adaptor.
Flow direction is simply altered by swapping the induction side of the vacuum to the exhaust and the relevant switches on the side panel flipped over, then a recalibration using the sharp edge orifice.
I use the same method each time so I can correlate one set of results against another and it seems to work very well.
I've retested a port or head months later and its still almost dead-on to what it was previously.
My basic setup mounted to the wall.
My basic setup mounted to the wall.
basic setup (1224 x 918).jpg (186.39 KiB) Viewed 10584 times
The calibration tube with the sharp edge orifice inside.
Calibration tube.
Calibration tube.
S8005864 (816 x 612).jpg (57.58 KiB) Viewed 10584 times
The tester is connected to a laptop computer and the proprietory software does most of the work for you.
All you need do is open the valve a set amount using a dial gauge and an opening fixture and press a button to log the data.
Data connector and data log button.
Data connector and data log button.
S8005878 (816 x 612).jpg (79.64 KiB) Viewed 10584 times

My most used opening fixture is made simply from a piece of tube, with two spaced holes to line up on the centre of the tappet and two fine pitch screws with machined tops for the dial gauge to register against.
The screws bear against a couple of threaded inserts inside the tube.
The tube part is bolted up in the bearing saddles for the head on test.
Opening fixture.
Opening fixture.
4valveopeningfixture (1224 x 918).jpg (140.39 KiB) Viewed 10584 times
A closer look at the tester.
You have several options with it, measurements in metric or imperial at the flick of a switch, including a handy "actual" flow position.
Flowtester in closeup.
Flowtester in closeup.
S8005860 (816 x 612).jpg (73.38 KiB) Viewed 10584 times
A head on test for bare port flows.
ontestBPF (1224 x 918).jpg
ontestBPF (1224 x 918).jpg (193.3 KiB) Viewed 10584 times
This is a Mazda intake manifold.
I'm blowing air through it to check how much flows through each runner, blocking each one off as i uncover the others one at a time.
Intake manifold on test.
Intake manifold on test.
DSCF0047.JPG (364.55 KiB) Viewed 10584 times
Regarding the seat cutters, I bought a set of Neway cutters some time ago and found them to be very easy to use and get great results with.
I know Guy swears by the PEG10 and I did buy one second hand and had it serviced but I simply couldnt seem to relax with it.
If I'm honest, it scared me! It goes so fast.
It's a fantastic tool though, if you've never experienced one it's an eye opener to see how it works.
However, I couldn't relax with it so I sold that and bought a Mira valve seat cutter, made in Switzerland which uses "formtools" to generate single or multiple angles in one pass.
Took me ages to save enough to buy one but it really does suit me down to the ground, makes no noise and seems more controllable to me.
Who would have thought that cutting valve seats could be so therapeutic?
The only thing that I've found you must ensure is adhered to when using this is that the pilot which rotates inside the guide must be as snug a fit as possible to give an accurate seat and i always oil them to ensure theyre lubricated as well to prevent sticking.
Mira, hand cranked seat cutter.
Mira, hand cranked seat cutter.
DSCF0144.JPG (367.39 KiB) Viewed 10584 times
Recut seat, opened out to true valve seat diameter, with 45 seat, 75 bottom and parallel throat cut done with the Mira.
Recut seat, opened out to true valve seat diameter, with 45 seat, 75 bottom and parallel throat cut done with the Mira.
P1030415 (1000 x 750).jpg (144.07 KiB) Viewed 10584 times
Tony Warren. GC #96.
Guy Croft
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Re: Self build flow bench

Post by Guy Croft »

Nice photo of the Mira seat Tony. Can I see a photo of the inlet port viewed from some distance so I can gauge the port inclination relative to the head face?

G
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