Mitsubishi Delica Owners Club UK™

[rekab6969]

Hi All,

Well, I'm making progress with cylinder head removal, found the "blow off valve" not sure of it's correct title but it's located at the bulkhead end of the inlet manifold, sprung loaded device.

Mine was covered in fibre glass resin / mat I guess in an attempt to stop it leaking... !?  It was along, with most of the inlet manifold covered in carbon oily gunge, all lovely and clean now, removed the fibre glass resin and it holds fluid if I fill the manifold with degreaser..

How much pressure do they take before they blow, should I renew it as it would be far easier to do it with the manifold off..?

What is their official title..?  

Thanks,

db

[Google]

[Deker]

Generally, that type of valve would be referred to as a Pressure Relief Valve.
In the is case = Inlet Manifold PRV.

Quite common to be mucky  

If you do not overtighten, it is quite easy to remove from the manifold, when on the vehicle.
IMO there is no need for it to be as tight as the manufacturer does it.

Mr D

[rekab6969]

thanks Mr D,

Ahh  a PRV..  Should have known that really, same as on a boiler..  

It is in there really tight, tried to remove it in a vice with a big pair of adjustables, but I stoped as I thought I'd do some damage if i carried on, it can stay in place if it's really required, but i need to know it is working as it should, what kind of psi do the run to..?

Thanks,

db.

[Deker]

PSI = Dunno  

Do yourself a favour - get it off, it will get loose, just apply tool pressure and wait -
Slowly applying more pressure. You can use heat from a blowlamp to help.

When I got mine off (in the car) I had to use a small bottle jack under the spanner - It was bl--dy tight  

Mr D

[rekab6969]

That's what we like to hear..  Can I fit a blow off whoosh dumpy valve in 't place...  

[rekab6969]

So it will be best taken off, and just plug the hole..?  db.

[Lewis]

Other names for the relief valve are a blow off valve or turbo overpressure dump valve. It is there to protect the engine. If it wasn't required then Mitsubishi would not spend money on making them, machining out the manifold and then fitting them.

If you remove it and block up the hole, then when, not if, you get to much pressure in the manifold the intercooler pipe will either split or, if your lucky, just blow off the manifold or the intercooler engine; or even where the intercooler hose it connected to the turbo.

I've only had mine go off once, which was whilst heading up a very steep incline, with a fully loaded van (camping trip setup), with my foot too far to the floor. Once I backed off and let it power down a bit it returned to normal running.

Personally I feel you are best leaving them alone, unless they keep blowing of in normal driving conditions. If it ain't bust don't try to fix it.

As for their pressure setting it is 35 ft.lb. (48Nm)

HTH
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[rekab6969]

Hi Lewis, thanks for your reply, I'm happy to leave it in place really, just need to know it's gonna work when required..  Plan on pressure testing it with air, I read some where they run 0.9bar turbo boost? do you know when they blow off at so I have an idea what PSI  to test it at..?

Cheers,

db.

[Deker]

B)

[Lewis]

Oops! Yes Torque Setting.

Having had a good perusal through all the workshop manuals I can't find any mention of what the blow off pressure setting should be set at.
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Copyright is retained for all my photos. Please don't copy them without asking permission
Do not blindly go where the path may lead you. Go where there is no path and leave a trail that others may follow!
ルイス

[rekab6969]

Kinda knew it was torque setting, wish the guy who installed mine had stuck to them..  flipping tight thats for sure..  I'm going to mess around with it to see what it blows PSI off at, just to see..  

Thanks for all.

Cheers,

Dave.

[rekab6969]

Hi Guys,

Set up a test rig for the PRV, wouldn't hold 3 psi...  Tried cleaning the seat but just the same..  

Going to replace it..  

Could that contribute to a blown head gasket / cracked head..?

Cheers,  

Dave.

[YOZA]

You could do as I did and replace the dump valve with an inexpensive adjustable unit.

You simply dial in the PSI you want the valve to open at and then blank the original weak valve, I used the EGR port to attach the valve to the manifold.




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Artificial intelligence is no match for natural stupidity....

[YOZA]

This is what the OEM pressure release valve looks like when you pull it apart.
It is a simple plunger and spring mechanical valve set to release at more than 14 psi.

http://i682.photobucket.com/albums/vv188/lubabailey/0248F748-EE49-43BE-AC41-89AFA37233D1_zpstgmr67cs.jpg

http://i682.photobucket.com/albums/vv188/lubabailey/DA2C87F5-B215-4B27-98BC-33B4A67E8E64_zpsqimxcvqz.jpg
_________________
Artificial intelligence is no match for natural stupidity....

[YOZA]

Oh dear, pictures are rather large..
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Artificial intelligence is no match for natural stupidity....

[rekab6969]

Hi,

I came to the same conclusion, to install a BOV to atmosphere. The PRV is the same as on a central heating boiler / system.  The pictures were large, especially when viewed on a mobile..     Thanks for the advice.  

Just need to sorte a head now..  

[YOZA]

There is a fully built used but tested head on a popular auction site at the minute.

The seller looks like a breaker with good feedback, good price too.

That would be the way I would approach your problem.
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Artificial intelligence is no match for natural stupidity....

[YOZA]

£190 free postage, that is a steal.
_________________
Artificial intelligence is no match for natural stupidity....

[rekab6969]

Stolen.    Thanks

[rekab6969]

Dare I ask...?  which make of head gasket to use..?