Small Garage Flowbench Build

[stef-1]

We had a beautiful English summer weekend so I took the opportunity to pull the flowbench outside and give it the second top coat of paint.



Then I got busy with fitting the counter top, deck plates, bleed valve, etc.







I fired it up again after fitting all the bits. It's not too noisy and seems to have plenty of suction. I tried out the bleed valve and it works well. The only thing with it is that when at the fully open position it makes a very loud high pitched scream. I think I'll have to fit an air filter or something to it to dampen the noise out.



The other thing I found was that despite lubricating the threads on the deck plates they were still a little awkward to use. It was also quite easy to drop them when you got them to the end of the thread. I decided to make up some handles from some aluminium strip I had lying around and fix them to the deck plates. It makes a lot of difference in fitting and handling them.



Next major parts to make are the pressure tappings, back board, hatch cover and manometers

[msj442]

i like the handle idea. i made a spanner wrench for mine but like your idea.

max

[stef-1]

Well, back from holiday and it's time to get stuck in again.
First job was to fix the scream from the bleed valve when at WOT. I tried a filter which muffled the scream a bit but was not satisfactory. Looking at the inside of the bleed valve I noticed that the ports for the original idle control valve were quite large and wondered if they may act like a whistle. I filled them with sealer and "hey presto!" the scream stopped
I then made a hook to tidy away the power leads when not in use and also fitted the other handles to the deck plates.





Then I started to make the pickups for the manometers. These were made from some copper brake line I had lying around and some copper plumbing pipe. I cut the brake line about 2.5" long and flared one end. The copper plumbing pipe I cut to 1" long and flattened in the vice. Then I drilled two holes in them: one a tight fit for the brake line the other for a fixing screw. I then used normal plumbers flux and solder to join them together.







A blob of sealer on the back of the flattened copper allows them to seal against the bench side panel when screwed in place.





I also began to make up the parts for the back panel which I wanted to be able to unbolt for easy transport of the bench.
I got rather side tracked at this point and was itching to try the bench out. I had a magnehelic gauge and electronic manometer so I rigged them up.



I used a 2.268" orifice in the bench and bolted on a 1.5" orifice on top. The bench easily pulled 28" test pressure and the depression across the bench orifice was 6". The readings were nice and stable.
A few calcs showed this to be:

154.8cfm for the 1.5" orifice at 28"
163.8cfm for the 2.268" orifice at 6"

A difference of 9cfm. Now is this good? Bear in mind that I did not use any clay to seal the orifice plates against their mounts and I don't know how accurate the gauges are. I guess there probably is some leakage somewhere else other than around the orifice plates?

[stef-1]

Thanks to Bruce I got the most important part of my flowbench on Friday... A PTS sticker!



On the next day I set about fabricating the steel frame for the back board which will hold the manometers. It's made from 3/4" square steel tube. The whole back board will be made to unbolt from the bench so that I can transport it easily in the future. Here is the finished frame painted black.





I also fabricated a mount for the bleed valve control. The control is an old throttle lever from a lawnmower.



Getting there!

[stef-1]

A little more progress made this Saturday. I made the rear hatch cover and got it painted. Just need to let it dry off and fit it during the week.



Then I began to finish off the connection to the bleed valve. I initially got it hooked up with a drilled M5 hex head screw and a couple of nuts screwed into part of a throttle linkage.



I found however that I could not get full travel on the bleed valve. It turned out that the radius from the cable connection point to the centre of the throttle shaft was twice as much as the radius on the control lever. I needed somehow to get a 1:1 ratio. A hunt amongst some scrap parts yielded another throttle assembly that had a linkage part I could take off and add to the bleed valve linkage. The part was spot welded on and then hooked up. After that it all worked well. I fired it up and connected the Magnehelic gauge again and I could control the depression very easily.





I also made up the first back board which will be used to mount the incline manometer and the Magnehelic gauge. The gauge I mounted in the lower right corner of the board. I will use this gauge, once I've checked it against the vertical manometer, to set depression so that I can use the vertical manometer for a pitot probe.

[jfholm]

Looking very good. It is also good to see all the different ways to skin the cat of building flow benches

John

[stef-1]

Thanks John!

[bruce]

[49-1183904562]

[stef-1]

I'm not 100% sure how sensitive it is... I want to test it against the vertical manometer once it's built. I could just build two vertical manometers but I had this gauge already. It reads 0-30" h2o and is easy to read. I thought that if it works well I will hook it up to set test pressure whenever I need to use a pitot probe to survey a port. I may use the digital manometer too if it reads well against a water manometer. May as well use what I've already got if they're accurate.

I am a bit nervous about building the manometers. I'm having a hard time trying to find some of the materials (like suitable wells, acryllic tube). Although I've read many threads on here about building them I may still be asking questions...

[stef-1]

Got a little more done on it and now it's starting to look like a proper bench.

Fitted seals to rear hatch cover and installed it.





I also gave the back boards their top coat of white gloss paint.



Started to fabricate the vertical manometer. It uses a 40" long steel rule. The top fixing is slotted so that I can use a plumb line to get it vertical.





I've also fitted a temp gauge to the front of the bench. It uses a bi-metallic probe that goes goes through the front panel and into the chamber. I just need to put some sort of cover over it so that I don't damage it.



I fired it up on exhaust mode for the first time and seemed to work well. The temp gauge recorded a 15degC temp difference after it had ran a little while.



Starting to look like a proper bench now!

[stef-1]

Vertical manometer mount painted white gloss.



Started work on the incline manometer. It's mounted to the backboard with slotted holes so it can be leveled when put in it's final position. The level is a little T-shaped one from the local hardware store.





Still struggling to find something to use for the wells...

[johno]

Have you thought of using syringes (without the plunger) as your resevoirs? You can get them in a large enough size and buy rubber 'corks' to cap them!! See site; "www.dtech.net" , he has used them with success! :;):

[Flash]

[johno]

Now that you mention it, the chemist did look at me a bit funny when i asked for a very small syringe (without a tip). I even told them it was for topping-up my vertical manometer! Vertical Manometer??! Must be hippie-code for drug lab.