faulty metering heads

[delorean12uk]

Hi-ya all, I've been chatting with my old mucker stinky Tony and heard that their are an increasing number of members with metering heads that have gone pete tong. I stripped one down tonight after Tony tried it on his car a couple of weeks ago and he said that only four injectors were working out of the 6, so I figured if it was knackered I would strip it down and if I couldn't resamble it properly it would be no Biggy.
They are infact very simple, and very clever and manufactured to a high spec and tolerances inside, their are seals in their but they were fine, and the control plunger has no seals at all, it is just a ground metal piston in a sleeve. And the fuel ports are to small to be machined so they were probably spark or wire eroded at manufacter. I suspect the problems with these heads not working properly is lack of use, I.E. fuel tarnishing and corrison or rust which could block these fine ports and hinder the main control plunger. I have managed to source a rust remover that will not damage the seals and left to soak for 24hrs could restore the metering head to it's original intergrity. I have checked a couple of US sites and although they can supply refurbished units, I suspect that all they do is exactly what I have just explained, and that is to strip them down and clean them. Bosch do not make a service kit because I've checked. The first picture is curtisy of Special T, but the second picture is one I took tonight after I stripped it down. My point being is, they are so simple their is nothing to stop it working properly unless it is contamined with either rust or fuel tarnishing or debris.

[Chris Williams]

I did the same as yourself, took one to bits for the hell of it. And totally aggree with your thoughts. The main problem that I found was trying to get hold of the 'O' rings for re-assemby. As these seemed to be a bit special and I could not track them down anywhere. But as you say it's not that hi tech at all!!
Chris

[NickT]

This looks v interesting.
Let's hope it will work !

Chris, how about getting a box of universal O rings - unless they are lipped or something.

NickT

[Tourettes Tony]

funny looking thing TT

[Chris Williams]

NickT Wrote:This looks v interesting.
Let's hope it will work !

Chris, how about getting a box of universal O rings - unless they are lipped or something.

NickT

Not too special Nick, just very small ones and very thin ones. None of which I could get easily.
Chris

[Darren C]

Try Oldham Seals in Chichester on 01243 782296.

They manufacture O'seals world wide, we have a chart at work with literally thousands of sizes they do.

You may need a BS number for the seal or alternately the internal diameter and the thickness of the rubber. (ie 10mm id x 1mm thick)

They do imperial sizes as well. Right up to QE2 propellor shaft seals!

Because they manufacture them they work out pennies each rather than pounds.

They also do different chemical composition throughout the range (ie high or low temp etc)

Worth a try.

Best Regards
D

[Rich H]

AFAIK the problem comes when you try and stick the two halves back together. Aparently it's impossible to stop them leaking.... However, having never tryied it myself, I'm only going on when I've heard.

[delorean12uk]

Well I've taken two a part now, a Delorean one and a Volvo one, I made sure the diaphragm was clean before reassambly and then I coated it in a very fine viscosity oil before sandwiching the 2 halfs back together. I must admit the seals in both of them looked very good and their were no signs of perishing at all. The Volvo one was filthy inside, not so much debris but when I clean the diaphragm a brown film was on the cloth I cleaned it with. Their is not a lot inside to make them fail, and they are very robust, the only conclusion as I said before is they are cloging up. The ports at the top where the pipes for the injectors bolt on to, inside their are filters as you can see by the pictures below, all I can conclude is they are breaking up and blocking it up. As of yet i have no Idea where to source these from, but I do know this, the Injectors have the same filter built into them as well. The picture of the good and bad filters are courtesy of Mr paul Knowles, the other pictures are of the Volvo head I stripped tonight. I have not tried these heads out yet but it will interesting to see if they do leak because their are no gaskets between the lower and top half of the head, just the diaphragm. Thats why I thought it would be better to reassemble them with a film of oil between the two halfs rather than putting them together dry. We shall find out, Chris Nic is coming over tomorrow with about 5 knackered heads, that'll give me something to do.




The image above is of a good filter and a bad one



The image above is of the diaphragm, I've tried to highlight the hole that is in it, this hole is the only connection from the bottom and top half, and connects the pressure control adjustment on the bottom cavity to the middle port on the top half where the pipe from the CPR connects to.



And this last image is where the bore for the plunger supplies the top half of the metering head to supply the injectors. again i have tried to highlight the slot where the fuel is forced through.

[NickT]

Just wondered if the rebuild has been successful or not.

I found this on the t'internet the other day and it oulines a repair procedure on the fuel distributor on a porsche. Same should apply:

http://www.porsche928forums.com/downloa ... ebuild.pdf

Good luck,

NickT

[NickT]

Any luck on this?

Reason I ask is that I have just bought a volvo venturi that came with 2 volvo fuel distributors (soaking in wd40 at the moment to try and release the plunger), 2 volvo cpr's, set of fuel pipes and a set of cam followers (new) for £60.

I may have to have the distributors rebuilt so I might as well have a go.
If it doesn't work I can always send it to Ken the fuel injection specialist.

NickT.

[Dan6457]

I saw those bits on ebay Nick :wink:

[NickT]

Dan1986 Wrote:I saw those bits on ebay Nick :wink:

Did you need any of them Dan ?

NickT

[Chris Williams]

NickT Wrote:

Dan1986 Wrote:I saw those bits on ebay Nick :wink:

Did you need any of them Dan ?

NickT

Funny old world the guy bought these bits of me to fix a fault on his car he thought was fuelling.......If I remember right turned out to be a bust cam chain! and ran on 3 cylinders all be a bit rough :o
Chris

[Dan6457]

NickT Wrote:Did you need any of them Dan ?

Not really, I thought about changing the cpr to match the rest of my volvo bits but theres no need really.

[NickT]

Chris Williams Wrote:

NickT Wrote:

Dan1986 Wrote:I saw those bits on ebay Nick :wink:

Did you need any of them Dan ?

NickT

Funny old world the guy bought these bits of me to fix a fault on his car he thought was fuelling.......If I remember right turned out to be a bust cam chain! and ran on 3 cylinders all be a bit rough :o
Chris

Yes that's right. He mentioned he got some of the parts from you !

Small world eh.....

NickT