Bespoke TR6 catch can

[Jonny TR6]

Hi Andy - looking to do exactly the same as you with regards to tapping a new breather outlet into the rocker on the opposite side ti the current.

Sensible discussion and exchange of ideas is what this forum should be about. I’m never too blinkered to be able to accept someone else’s advice/guidance/experience and the more I learn, the better.

Agreed on the principles of a low pressure downstream pulling through gas/fluid, just don’t ask me to calculate either of them.

Bl00dy Italians ! (No offence to our Italian friend on here).

 

[john.r.davies]

Much of the above discussion relates to four cylinders, with  which I'm not familiar, but if you want to redesign the crankcase venting system I'd suggest using a vent directly from the crankcase, rather than via the pushrod tubes.

The 6 offers an excellent vent, if you junk the fuel pump, but if you are considering the fitment of a vent to a different place in the rocker cover, why not drill and tap the block?     The point is that a low-placed vent and a catch tank placed higher up allows the oil vapour to condense in the hose and run back into the sump, while water vapour and blow-by gas escape via the vent on the catch tank.     A wide bore hose, at least 1"  slows the flow of gas and allows more time for oil condensation.

The result on my 2.5 engine is that I never see any 'crud' in the catch tank at all!

John

[Andy Moltu]

It's tricky to fit a decent vent to the fuel pump blanking plate on a PI cars as the metering unit obstructs access. Hence the reversible option of doing so on the alloy rocer cover. There is enough of an incline to allow most of the oil vapour to condense and drain back. 

To be fair it's a bit of overkill that I did (to be fair I didn't weld the alloy myself) as a temporary fix for a build with a lot of blow by from glazed bores. A good honeing removed that in the end.

 

[john.r.davies]

Andy, I agree with you on access!  But I made an alloy plate drilled to take a right angle central heating connector.   It's best to fit the hose as well before the M/u, as access is cramped!

John

[DRD]

22 hours ago, Andy Moltu said:

Certainly agree you want it to vent under the car.

You can use the smaller round ones, but they can fill with oil quite quickly. Ideally put a drain in the bottom and connect it to the the block where the fuel pump goes. (Assuming you have gone to an electric pump you can adapt a blanking plate). This allows oil to drain back to the sump.

I wouldn't do that considering that most of the liquid in my tank is water!

[stuart]

18 hours ago, Jonny TR6 said:

Yep, but I’m not paying their prices for a fibreglass box that you have to chop around and make a bracket for. 

You don’t . It fits right in neat as you like next to the battery box and is fixed with one bolt through the side of the footwell top it also has a large bore hose as an outlet breather to reach down under the car to face rearward for the Venturi effect, even after a lot of hard thrashing I only ever get about half inch of water in the bottom of the tank, it’s a well thought out and well designed bit of kit, agreed it’s expensive but it does exactly what’s required 

Stuart

Edited June 4, 2023 by stuart

[stuart]

1 hour ago, DRD said:

I wouldn't do that considering that most of the liquid in my tank is water!

As it should be 

Stuart

[BaulyCars]

On 6/3/2023 at 10:52 PM, Jonny TR6 said:

Tang at the lower front edge to locate onto the chassis member with a rivnut and tangs along the left edge (looking from the rear) to locate onto the top of the chassis where the brake lines run (under the brake lines).

Hi Johnny, 

Had a rough go at what it might look like if that helps discussion. 

If you didn't want to touch the bodyshell I think you can use the battery tray upstand to clamp to and you might reach a bracket out to the inner windscreen wiper motor bolt. 

I doubtless don't have the inlets where you were thinking (and not angled towards the rocker and block) and the top outlet would need a 180 deg fitting to dive a hose down past the gearbox. The volume is just what looked about right, but not sure what size is really needed.

I put in a line to show a lid of sorts for clean out, although also assume any lid needs to seal reasonably well if you want to pull any sort of vacuum through the tank.

Could probably 3D print one to see how it fits (I've a LHD US car but could dodge the steering column with the 3D print shape).

Hope that's helpful,

Kind Regards

Toby

 

Edited June 5, 2023 by BaulyCars

[Jonny TR6]

Excellent - thanks Toby. If you're ok to tweak the file, the design amendments would be as follows;

Looking at the front face - inlet on the left, outlet on the right. 

Outlet has a 45 degree elbow to take a 13mm ID pipe.

Inlet has a 45 degree elbow to take  13MM ID pipe. This feed comes from the crank case (fuel pump blanking plate).

Drain cock at 45 degrees located on the front left side, as low down as practical. Doesn't need a massive bore.

Then looking at the top -  inlet on the top should be located on the left hand side, 45 degree angle towards the front, to take 13mm ID pipe. This feed comes from the rocker cover. I was going to position it at the same height and distance from the edge as the other inlet on the front.

Final amendments..

The height is approx 45mm higher than your height, but vertical from the top of the horizontal panel where the brake lines run, so effectively angled as you've shown and then vertical.

Back of the unit is square on, same as the front.

I'm allowing for a mounting tang on the front face, to the right of the drain.

Really looking forward to seeing the final iteration. I've mocked it up in card and sent all the dims off this morning so don't have them to hand unfortunately. From memory, the bottom width is 55mm, top width 85mm and overall depth front to back 200mm. It can all be tweaked to get the optimal design.

Cheers

Jonny

 

 

Edited June 5, 2023 by Jonny TR6

[stuart]

Personally I would go with bigger pipe sizes for block inlet and main outlet like this 

Stuart

 

[Jonny TR6]

23 minutes ago, stuart said:

Personally I would go with bigger pipe sizes for block inlet and main outlet like this 

Stuart

 

Thanks Stuart - appreciate that bigger is better, but given the starting position of just breathing into the plenum and not wanting to swamp the engine bay with pipes, I'm comfortable with the feeds. Might increase the outlet to 1" though to help the Venturi.

Edited June 5, 2023 by Jonny TR6

[john.r.davies]

As I said above, a larger tube allows lower gas velocity and more time for oil to condense out.

John

[Jonny TR6]

16 minutes ago, john.r.davies said:

As I said above, a larger tube allows lower gas velocity and more time for oil to condense out.

John

Sorry John - good point and well worth re-iterating, I'd missed that.

[BaulyCars]

Hi everyone, 

Below are a few updated shots of the oil catch tank following continued discussion with Jonny on the design.

Key updates as follows: 

• On the front face the inlet on the left (from fuel pump blanking plate) and main outlet on the right (down to chassis/below car) are both shown as 3/4 inch (19mm) ID. 
• The side inlet is from the rocker cover and shown as 1/2 inch (13mm) ID.
• Front face has the oil level sight tube and lower drain cock.
• Front and side inlet both turn down internally, stopping short from the bottom of the tank. The outlet continues further into the depth of the tank to give more separation from the inlets.
• Full length baffle plate, with the area above the plate to hold filter material (coarse steel-wool or similar).      
• The inlets/outlets are shown as barbed ends (if there's a convenient off-the-shelf fitting), but could more easily be flared/bubble ends in stock aluminium pipe and use of hose clamps. 
• The lower drain tap is shown as one of those 'EZ' oil plug taps, but could be a fuel-type pedcock (although they're quite small), or just a welded bung/plug.   
• Two mounting brackets on the side, one on the lower front, positions/size tbc. Deleted the bracket on the left for the battery tray to simplify things. 

So still very much 'conceptual', but great to get more input/thoughts, any key things missed or could be better?

 

 

 

 

Cheers

Toby

[john.r.davies]

Toby,

What is the volume of the tank?   I could estimate from the  sizes of the inlets/outlets, but more accurate to ask you!

Did you consider the Motorsport UK's "Specific Regulations for car racing" Q.13.7.2, " Have any engine oil tank breather or overflow tube
venting into atmosphere, led into catch tanks which have a minimum capacity of 2 litres. For engine capacities in excess of 2 litres the catch tank capacity must have a minimum capacity of 3 litres." ?   My underline.

John

[BaulyCars]

Hi John, 

The internal volume (ignoring the volume of the walls of the tubes and baffle plate) is currently 2,403cm3.

Better to try for 3 litres to meet those requirements therefore?

Would be a shame to go to the effort of a bespoke tank and it not be motorsports compliant...

Let me see if there's room to 'go up' - can't really go wider as up against the battery and bodyshell. 

 

Cheers

Toby 

[Jonny TR6]

From memory the front to back is currently 200mm, you can go to 230mm and the bottom width can go to 65mm. Top width would obviously increase as well. Should hopefully expand it to 3L !

Edited June 8, 2023 by Jonny TR6

[BaulyCars]

You're dead right, there's quite a lot of room back there - I'm seeing 236mm front to back, I'll try the 230mm.

 

Edited June 8, 2023 by BaulyCars

[BaulyCars]

230mm gets you there in one go...!

[john.r.davies]

Thank you, Toby!  I hoped that you would take my comment as constructive, and you did!

There would be few customers wanting to race their TR6, less than twenty overall the UK, I suppose, but MotorsportUK do write their regs with experience and knowledge.   And anyway, "MotorsportUK Compliant" would not go badly in the sale pitch!

I long ago adapted a header tank from a different marque as my catch tank, so I fear that's less than 19 racers to sell to!

Bests

John

[BaulyCars]

It'll be one of the headline specs!

Thanks for raising it, John, just the sort of feedback that's needed. 

Any other thoughts on what you'd have liked to have done on your own tank would be great too.  

[andyhall]

Hi

I have the Revington catch tank on my 6, fixes to the battery bracket and bulkhead.

[andyhall]

obviously the holes are in the top

[stuart]

Just now, andyhall said:

Hi

I have the Revington catch tank on my 6, fixes to the battery bracket and bulkhead.

Which breathes fumes back into the engine bay, hence why Im not a fan of them Im afraid.

Stuart.

[BaulyCars]

Thanks, Andy, its a good tank and a benchmark. 

Like Stuart says we're guiding the outlet vent to the bottom of the car rather than into the engine bay, and the rocket cover inlet is set on an angle to better pick up the incoming hose line from the rocker.