6mm ID bio proof hose recommendations

[BANDIT2]

Only need a MTR .
For my space heater and a karcher steam cleaner I'm trying to fix.
Normally I convert everything to nylon air tube but it's not practical on these two jobs.

[Tony]

Is it because you need something more flexible than nylon? (Nylon is my go-to as well - there's a reason it's used on Merc fuel systems!)

I've used SAE J30R9 injection hose (often just sold as "R9 injection hose") before in the engine bay where it gets hot (food grade clear braided hose bubbled in just a week in a hot location!)

The confusion with this stuff is the coatings, Viton and/or "Hypalon" (polyethylene based).  Viton is great with biodeisel but Hypalon "unsatisfactory" according to these compatibility charts:

https://westcoastcollaborative.org/files/BBG/enduser-appendix/National-Biodiesel-Board-Materials-Compatibility-factsheet.pdf

You want the stuff marked FKM-NBR-CSM (FKM is an Americanisation of the brand Viton) - the FKM is the inner lining.

Examples:
https://www.thehosemaster.co.uk/r9-unleaded-petrol-diesel-ethanol-automotive-fuel-hose/
https://www.ebay.co.uk/itm/FUEL-INJECTION-HOSE-VITON-LINED-CODAN-SAE-J-30-R9-CAMPER-VAN-Etc-1-MTR-X-5-6-MM/224137951307

There are others which are cheaper, but it's unclear whether this one has the FKM component we need:

https://www.ebay.co.uk/itm/6mm-Rubber-Fuel-Injection-Hose-Petrol-Pipe-SAEJ30R9-5-6mm-1-4-I-D-Unleaded-UK/260780661987

[BANDIT2]

The nylon won't seal on the plastic moulded barb on the fuel nozzle holder on the space heater. Rubber hose works well but tends to weep and split after a while. I had a fire this morning when a split hose caught fire! Bit of excitement when it carried on burning when switched off.
The steam cleaner needs two shortish lengths but the moulded plastic barbs are different sizes slightly which the old rubber hoses coped with but the nylon doesn't plus the bends are too tight really.

[neisel]

I bought 5m of TYM 6655 to solve a problem of BD eating Mercedes OEM leak off lines. I tried nylon but couldn't get it on satisfactorily.

I've used approx 1M each on 3 different OM605s & 606s & it's performed without issue - no degradation, no leaks, no popping off, no nothing. Seemed expensive at the time but 7 years later not in retrospect.

https://tym.co.uk/products/fkm-rubber-tube

[BANDIT2]

That sounds ideal, shame they don't do 1 MTR lengths. 5 is just too much expense.
I've ordered some stuff from hilltop products, fuel injection stuff that says bio proof and was quite pricey £12 or something per MTR plus postage. Should come tomorrow maybe.

[neisel]

They do sell it by the metre.

https://www.ebay.co.uk/itm/VITON-RUBBER-TUBE-3-2MMID-X-6-2MMOD-4MMID-X-6MMOD-6MMID-X-8MMOD-6MMID-X-12MMOD-/330791985596?var=&hash=item7dbf6ae103

[Tony]

Well this all comes with good timing as the fuel hoses on the Merc seem to be turning to cheese.



The fuel system is a funny one on this engine, the fuel inlet (10mm ID) comes through a fuel heater built into the EGR pipework from the exhaust manifold, so must get warmed by EGR gas flow.   After injection any IP excess/leak-off returns to the tank via FPHE cooler on the water circuit via 8mm ID pipes.

[BANDIT2]

SAE J30R9 is printed on this hose which turned up yesterday. Gotta be better than the stuff I was using on account of these fancy markings .
I'll stick it on and report back when it's had a decent test. The space heater is used a lot now and the hose is constantly full of bio so if it fails I should know by the spring.