Ricardo hydraulic clutch hookup

Does the fitting (Ricardo metric to either -3 or -4) require and special sealing washers?

I was just reading something that says metric to AN ususually needs some type of o-ring or sealing washer. Don't want to pull it off until I know what to expect, hehe.
 
Does the fitting (Ricardo metric to either -3 or -4) require and special sealing washers?

I was just reading something that says metric to AN ususually needs some type of o-ring or sealing washer. Don't want to pull it off until I know what to expect, hehe.
it's inverted flare. make sure you hold the tee with a wench while removing so you don't bend the mounting bracket.
 
Alright, I'm going to be doing my clutch line shortly. Before I order 1/4'' hardline from Inline Tube, I just wanted to see if anybody else lately was using 1/4'' tubing for the clutch line on ttheir builds?
 
I'm using the 3/16" line supplied form inline and i don't get any Ricardo clutch slippage. In fact i get the opposite. On high RPM first gear launch, i get a loud thud from the clutch even a little chirp asscociated (not from the tires). The first 50 or so miles i never heard this on full burnout. It progressively got louder. I've got the standard Ford clutch, not Stillen. I know ceramics or stage II's will give a thud but i'm wondering if anyone else gets this from the standard Ford clutch?
 
Clutch line question time - would it be a really bad idea to run braided AN hose from the front to rear of the car for clutch (-4an or 1/4'')? I know it's bad to do with brakes (something like heat expanding the fluid?), but what about clutch?

Also, are there any general rules with regards to hardline vs braided AN line with clutch? For example, keep the AN line sizes down to a bare minimum unless you want to experience clutch slipping and other problems?
 
Clutch line question time - would it be a really bad idea to run braided AN hose from the front to rear of the car for clutch (-4an or 1/4'')? I know it's bad to do with brakes (something like heat expanding the fluid?), but what about clutch?

Also, are there any general rules with regards to hardline vs braided AN line with clutch? For example, keep the AN line sizes down to a bare minimum unless you want to experience clutch slipping and other problems?
the clutch does not have as high a pressure as the brakes. you could run braided all the way. the clutch slippage is caused by to small a line. with a small line there is a lag time from when you let the clutch out untill the pressure bleeds of on the slave cylinder. on a hard launch the clutch does not grab quik enough and slips. it is the same as letting out the clutch slowly and the clutch will slip until all the way out. Fran uses 1/4" line
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Will Campbell

Supporter
the clutch does not have as high a pressure as the brakes. you could run braided all the way. the clutch slippage is caused by to small a line. with a small line there is a lag time from when you let the clutch out untill the pressure bleeds of on the slave cylinder. on a hard launch the clutch does not grab quik enough and slips. it is the same as letting out the clutch slowly and the clutch will slip until all the way out. Fran uses 1/4" line
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I thought that the default, and correct, size for the Ricardo clutch line was 3/16", as Cam, I, John Salmon, and all the other Ricardo-based SLCs I've seen have. I know for a while, there was a discussion that engagement issues when hot were line-size related, but I think in the end the final diagnosis was that the fluid was boiling because the then uninsulated line near the slave was picking up too much heat from the exhaust (which is why the original FGT had that foil-like insulation on that part of the line). The original issue, IIRC, wasn't too-slow release, but an inability to disengage the clutch when hot.

When I drove an SLC with the 3/16" hardline, a Ricardo, etc, it didn't have an engagement issue- in fact, the clutch felt pretty good. That's only one data point, but it reassured me about the issue, anyway.

I also think that running flex hose for that length might actually worsen the problem of too-slow response. One characteristic of flex hose is that it swells under pressure. Rubber-core lines are worse than the teflon-lined hoses in this respect, which is why the use of teflon-lines hoses in braking systems is a typical upgrade for performance cars-- the effect is to firm up the brake pedal slightly. As is pointed out elsewhere, the clutch hydraulic circuit doesn't have as much peak pressure as a braking system, so perhaps that might mitigate the tendency to swell.

The swelling issue, and the concomitant change in the response curve is why I think it is normally better to run hard line as far as possible, and to use flex line when needed to account for movement of vibration.

Which, incidentally, is just how RCR designed the car.

My $.02, anyway.
 

Dave Lindemann

Lifetime Supporter
My Lotus Esprit S1 came stock with a red plastic line for the hydraulic clutch. Invariably these early cars developed what is affectionately called "red hose syndrome". The hose would bulge causing all sorts of clutch problems. The accepted "fix" was to replace the plastic hose with a teflon-lined braided hose. I made this mod to mine and never had a problem again. I agree that a hard-line running most of the way with a short braided line to allow for some movement would be the best solution but I think a full length braided line would work.

Regards,
Dave L
 
Okay, scrap my idea then.

But now I'm back to 3/16 vs 1/4, ahh! :eek:

If one goes to 1/4'', is there any downside to the larger line, other than it costs more?
 

Will Campbell

Supporter
I don't think there is a disadvantage to a larger line; I'm just not sure there is any measurable benefit.

I would guess that the smaller line would have better response, and make modulation of the clutch more precise, so if true, that would be a possible benefit for the smaller line.
 
Aparently smaller lines are suppossed to cause the clutch to respond slower on the release action.

I have used 3/16 plenty of times and never had an issue.
To much braided line as Will Campbell stated will reduce the throw and over that distance I would say a fair bit.
The braide only wants to be the flexable link between the engine and chassis.

You need to make the decission and just get on with it Alex.

jim
 

Ian Anderson

Lifetime Supporter
Supporter
To move a slave cylinder 1 inch (About what is required) you can work out the volume of fluid you need to pove into it. You know pi*r*r*1 inch. Now this amount of fluid has to get down to the slave cylinder through a single piece of pipe.

So The larger the diameter of the pipe the quicker you can flow the required volume for the slave.

3/16 to 1/4 does not sound like a massive increase in cross sectional area but it is and if you want your slave to release with maximum possible seed (clutch dumps and quick gear changes)go with the larger diameter pipe.

There are numerous thready already in the GT40 section that relate to this and the clutch drag/ slip that happens when the fluid flow rate is too low

(GT40's used the Renault UN1 and it's slave is 1 -1/16 so fluid required is high - others have kept the narrower pipe and sleaved down the slave cylinder meaning less volyme required - also means changing Master cylinder to rematch sizes.

And yes a 1/4 braded flexible pipe the whole length will work fine

Ian
 
For anybody who reads this down the road, I ended up going to -3. Fran confirmed all the shop cars are using -3 and he thought it was a heat&air bubble issue. So fingers crossed for -3 - I'd hate to pull it apart again down the road, haha!
 
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