Mk7 Injector Torque

[rossco_pb]

Still putting my 2.4L RWD mk7 engine back together and bunged the injectors in today and used the 6nm and 180deg and seems pathetically not tight?

When I first removed them the bolts they were really easy to undo, ie not tight at all. Is there a "better" torque setting that people use as the Ford spec just does not seem enough (in my untrained unprofessional) opinion?

And then on top of what is the proactive way to check they are need to be tightened given the bolts are supposedly throw away but for the life of me cannot understand why?

[metalworker0]

Bolts are usually throw away because they are what called "torque to yield" bolts - or commonly known as stretch bolts .. one use only .. the bolts actually stretch when torqued so no use a second time around.. as they have carried out their purpose. and it may well be that .. they have already been used a second time .. which may be why they are loose .

because they usually stipulate a torque, then an angle .. like 180 degrees .. this angle tightening is to stretch the bolt .. so acts as a locking method on the bolt .. the bolt does not "unstretch" once taken back out .. hence one use only.


all the best.mark

[Galway]

Hi.
Amateur here.
When you say "not tight" on tightening, you mean you felt the brackets were not tight in place or doing the final 180 was too easy?
Tightening new ones to specifications, I felt the opposite and feared them snapping.
Did you ensure that the threaded holes were clear of liquid first, in case you are bottomed out tightening against it?
If you reamed a significant amount of seat that the copper seal washer sits on, maybe you need a thicker seal washer?
And yes, replace with new bolts and now is a good time to double check if your 6Nm wrench setting is accurate.

[vansit1]

i felt that +180 was really easy too, but i dont think that it is incorrect, because it is the spec and there is no way its gonna move anywhere. 1 of the bolts even got a bit bent during shipping, so i just straightened it out with my fingers lol
i might have had a bit of oil in the holes tho, because the old ones looked a bit black-oilish, so maybe stiff bolts have some junk in the bottom already?

[metalworker0]

i felt that +180 was really easy too, but i dont think that it is incorrect, because it is the spec and there is no way its gonna move anywhere. 1 of the bolts even got a bit bent during shipping, so i just straightened it out with my fingers lol
i might have had a bit of oil in the holes tho, because the old ones looked a bit black-oilish, so maybe stiff bolts have some junk in the bottom already?

You must be a big strong chap to be able to straiten bolts out with fingers, did they run over them with a fork lift truck, dont put oil down the holes .. because it could cause hydraulic lock up , do clean the holes out with a tap.

i reckon if they where good bolts they would snap before they bent .


all the best.mark

[rossco_pb]

Cheers Mark, finally got it going. Hopefully all done right enough lol
As for injector bolts have paint marked their tightened position and will monitor them over time

[knobby1]

Cheers Mark, finally got it going. Hopefully all done right enough lol
As for injector bolts have paint marked their tightened position and will monitor them over time

The bolts don't usually come undone, they either snap or the copper washer gets hammered causing them to come loose.

Lord Knobrot (Smithy)

[rossco_pb]

So if they come loose due to the copper washer squishing or injector hammering can you just tweak the bolts? Would assume so as they certainly are not under much strain at the point?

[knobby1]

So if they come loose due to the copper washer squishing or injector hammering can you just tweak the bolts? Would assume so as they certainly are not under much strain at the point?

No....Injector clamp bolts are "single use" stretch bolts, torque to yield...once torqued to yeild point they're essentially useless and prone to snapping if torqued again.

Lord Knobrot (Smithy)

[vansit1]

u would have to replace the washers then, aka take the bolts off, clean the holes and then use new bolts
p.s. if they snap at normal spec, then maybe someone sells the wrong ones?

[metalworker0]

the right bolts will have the tensile grade on them , like these .. "10.9"

https://www.ebay.co.uk/itm/363615682426?


all the best.mark

[vansit1]

i dont think 10.9 needs to stretch, so those are def the wrong ones. might be for mk8 only, espec when its m7 also?

[metalworker0]

i just put the link there as an example , and since it was the only listing i could find that showed the bolt head ... dont know if its the wrong part number for his transit .. it was put there to show that it had a grade on it


all the best.mark

[knobby1]

i dont think 10.9 needs to stretch, so those are def the wrong ones. might be for mk8 only, espec when its m7 also?

Mk7 Euro-5 and Mk8 Euro-5 are the same.

Mk7 Euro-4 use different bolts to the above as they run a different fuel injection system.

Lord Knobrot (Smithy)