928 at last

High all, just about to do this job on my '90, and I'm looking at installing some additional insurance along with the new line by way of using fire sleeve over the hose itself. I need to know how long the entire assembly is though to order the sleeve.

Anyone ever measure the length end to end?

TIA,

ROG100

I have your hose in front of me
Total length - rigid pipe and rubber flex = 120cm
Length of Rubber flexible hose = 55cm
Rubber hose already includes a length of insulated section/sheath = 20cm

928 at last

Thanks Roger!

skpyle

Hello 928 at last,
Here are some unsolicited photos of how I did the same thing to the new high pressure PS line for the Red Witch. I used DEI Firesleeve, silicone self-fusing tape, and stainless steel zip ties.
If I had it to do again, I would have cut the firesleeve longer to go further onto the metal pipes. Eh...it is what it is.















Note: rubber 'doughnut' isolator has been turned inside out to make it easier to get off the line.





'Doughnut' isolator turned back right and reinstalled over the metal restrictor.
























Good Luck!

Petza914

Seth, did you do both the PS hoses since they run in the same area or just the high pressure one?

j.kenzie@sbcglobal.net

Looks great Seth!! This is a great idea.
Thanks,
Dave

skpyle

Pete, I intend to also cover the flex section of the return line when I install it. As of yet, I have not replaced the flex section.

The Forgotten On

The return line has next to no pressure and is more likely to weep than it is to spring a serious leak.

I would just replace it and not fire sleeve it.

karl ruiter

Good to get the number from Roger for your actual hose. I just replaced on my '88 and the replacement hose was quite different from the original.

mike77

My high pressure hose burst a few years ago. One thing I noticed is that the existing heat shield on the stock line actually prevented the fluid from spraying directly into the engine bay. Most of the fluid dripped down the inside of the sheath and out underneath the car. So I'm wondering if it is a good idea to put a clamp at the bottom of the hose? If the line bursts then the fluid will find a way out somewhere so perhaps allowing to flow downward away from the hot bits might be best. Just a thought.

mike77

Also when my ps line blew and I repaired it I simply got the most readily available dex III ATF to replace the ATF. Subsequently I did a little research and found that the flash point of most Dex III seems to be around 200c (more or less). Redline do one with a flash point of 238° C (460° F).

https://www.pegasusautoracing.com/do...ocID=TECH00046

I'm wondering if that extra 40c might give a little extra insurance. Don't see how it could hurt. Would be interested to know what the actual engine bay temps actually reach. I've read one thread that said the exhaust could reach 250c but that appears to have been an estimate rather than an actual measurement.

FredR

Mike,

I would not call that "a thought"- it is more a wake up call and I would strongly advise Seth to remove those clamps. It is a bit like sticking a condom over a fire hydrant and expecting it to hold- no way. More to the point, as and when it did let go it would have the opposite effect to that intended in that in all probability it would cause the resulting spray/mist to go exactly where you do not want it to go- all over the HT kit.

Perhaps more poignantly, it might be better to question the concept of placing a shroud over the line. If one has an old line of questionable integrity and no access to a replacement, an open sleeve covering the full length would be a useful temporary measure until a sound hose can be installed. On the other hand, if the basic installation is not sound then the high pressure hose as designed should not there in the first place and that is just not the case- but if it helps owners sleep better fair enough. I doubt a new hose would fail but we know for sure heat and age take their toll and continued use of such item that is 25 years plus old is just DF stupid. When I changed out mine recently the high pressure hose showed no signs of failing but the low pressure hoses were in an appalling state! Absolutely no point in sleeving the low pressure hoses IMHO, the HP line- well it does no harm but if I were to do that I would install it "banjo to banjo" as it were and then if there were to be a leak it would flow out downwards over whatever is underneath [the alternator and the steering rack].

For general information - Regarding flash point there is a lot of confusion as to what this term actually means. Folks regularly confuse flash point for auto ignition temperature [they are not one and the same thing] and I suspect you may have this common misinterpretation given the numbers you have quoted are more consistent with ATF auto ignition temperatures thus the correct concept but incorrect terminology for what little it is worth. The flash point of ATF is in the region of 160C but that is the temperature at which it can be ignited in the presence of an ignition source. The actual auto ignition temperature of ATF will vary according to what is in the brew. Redline are very much into synthetics technology and as I am concerned make great products and whereas "everything helps" it is not what I would call sufficient "justification" for using it but knowing Redline I am confident their product would give superior performance- just wish I could get hold of their products over here like I used to be able to do many years ago!

mike77

I'm thinking it would be sufficient to remove the bottom clamp only which would encourage any high pressure leak to go downwards.

Regarding the flash point, I'm quoting the technical specifications provided by the manufacturers. 200c ish seems typical for the ones I've checked. Surely flash point is the concern as that is where the ATF might combust if spraying over a hot engine? If that's the case then higher flash point would be better? Given the ps only holds 0.7L then cost not really an issue.

One thing I noticed was my high pressure line did not look very old. The PO must have changed it not that many miles before selling to me. So it seems to me you could put a new one in and be unlucky and see it burst a few years later. Perhaps my parking spot made thing worse as it required multiple full lock turns to get in and out.

FredR

Mike,

As I recall the flash point of ATF is in the region of 160C to 180C but that is not really the point. The higher the flash point the better but the problem is that cars with catalytic converters typically reach about 750F [400C] and thus the ATF flash point spec is not really of any real world significance in terms of preventing ignition of a leak thus the primary mitigation is to ensure as best one can the integrity of the hose itself..Vanster's car-b-que got me off the pot as it were

I see no point in clamping a sleeve after fitting one and claming on one end may permit one leg to fill with ATF in the event of a leak.- The sleeve concept only exists to kill the high velocity that would emanate from a pinhole leak and that could be done with a length of garden hose or whatever is lying around in the garage.that can withstand ambient engine bay temperatures [ circa 100C?].

I very much doubt your user profile had much to do with your issue. My hose looked in excellent cosmetic condition when I removed it but whether it was close to failure or not who knows? Careful inspection did not reveal anything suspect but...?

skpyle

mike77 and FredR, VERY good point! I will remove the clamp and self-fusing tape from the lower fitting on the PS pressure hose. I DO want it to channel a leak down and out as opposed to up and on fire.
Thanks for the advice!

The Forgotten On, definitely something to think about for the return line. I forgot it is under very low pressure. I am now on the fence about fire sleeving it...will evaluate at installation time.
Thanks!