Reaming injector seats

[therightangle]

Hi all,

Looking for opinions on how Im reaming injector seats.

I've just taken injectors out of a mk7 Euro4 2007 Transit 65k miles camper and reamed the seats manually. 3 seats have turned out nice and shiny but one seems to have grooves on it radially, from outside to centre.

I hope the pic has loaded successfully.

I'd almost suspect it kinda matches the hex impression on the outer edge of the injector but these marks go all the way in.

Also, the 17mm reamer fits best as mentioned on here, but I think a 15mm had been used on all the cylinders before as the 17mm sits too high to get the seat clean and just cleans the outer ring.

So I used both, and the higher outer lip that was there before can be seen in pic, and as the genuine copper washers are less than 15mm OD then I hope that part won't be a problem.

Any thoughts on the radial marks? I've reamed that one for ages and it improves slowly but I guess I'll have to keep going and get the marks out of it?

Thanks, great forum!
I wouldn't have gotten this far without it

PXL_20260211_150054476~2.jpg

[metalworker0]

is there any chance that a washer is still in there ... and you are reaming the washer


all the best.mark

[Airthies]

You need to ream with the 17 as the ridge is from the washer impacting the seat. Grooves are caused by cutter "chatter" it can be a pain to get rid of once it appears.

Wrap electrical tape around the shaft of the reamer arbour (if you check against the injectors there will be a worn mark just below where the rocker cover seal sits, this is from the rocker ladder support) wrap the rape at that hight (anticlockwise wen looking down from the drive end to stop it unraveling we you turn the cutter) and to a diameter at under the size of the injector support.

Steady constant pressure should clear the chatter.

Remember a slight bit of light grease as you cut to help keep the cuttings from going places you'd rather they didn't

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[Airthies]

is there any chance that a washer is still in there ... and you are reaming the washer


all the best.mark

Tell me you have no experience of doing these without telling me you've no experience


If the 15mm is cutting the seat and the 17mm is cutting the proud outer edge then there's no washer left in the hole.

And IF the washer was in the hole you'd get orange swarf rather than silver or more likely you don't actually cut anything as the washer just sits and spins.



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[metalworker0]

You're right, no experience , but you're just taught me some, thanks.
I was looking at the picture and seeing hints of not copper but brass, which sort of made me think of these plated brass fake washers id seen a few youtube videos on the subject a few weeks ago

all the best.mark

[Airthies]

You're right, no experience , but you're just taught me some, thanks.
I was looking at the picture and seeing hints of not copper but brass, which sort of made me think of these plated brass fake washers id seen a few youtube videos on the subject a few weeks ago

all the best.mark

Sometimes less is more

Take that info, keep it, use it for yourself, and once you've physically done it and understand the act feel free to forward on your experience.



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[therightangle]

Thanks to both of ye lads for replying.

Fair cop re the brassy tinge in the photo, I was wondering too what it is when I saw it, strange. All 4 copper washers came out like new on the injectors.

Re the reaming, I was doing it by hand. I guess the last guy might have had it powered by a drill with that chatter. I might upgrade to a ratchet bar when having another go, easier on the wrist hopefully!

[Airthies]

Thanks to both of ye lads for replying.

Fair cop re the brassy tinge in the photo, I was wondering too what it is when I saw it, strange. All 4 copper washers came out like new on the injectors.

Re the reaming, I was doing it by hand. I guess the last guy might have had it powered by a drill with that chatter. I might upgrade to a ratchet bar when having another go, easier on the wrist hopefully!

Chatter is not uncommon with hand reaming. I wouldn't get over excited about it and the T bars with most kits are usually sufficient if you go steady and keep it even.
That's why I'd recommend using tape to expand the shaft diameter which will reduce the risk of sideways movement when cutting.

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[knobby1]

That's why I'd recommend using tape to expand the shaft diameter which will reduce the risk of sideways movement when cutting. Sent from my Pixel 8a using Tapatalk

Good advice that..!

Lord Knobrot (Smithy)

[therightangle]

Thanks for advice so far

I've hopefully attached an updated photo which is bothering me as my cylinder number 3 almost looks like it's worse after reaming, but maybe I'm overly concerned?

I think I can see slight nicks and undulating radial lines. No such issues in other cylinders and these were done in a minute each.

Another thing is this cylinder 3 would appear to be about 0.3mm below the other seats now after it had a lot more reaming than the others, but with regular stops and checks. I've been trying to get rid of the radial lines and other blemishes all this time.
Hopefully that kind of height difference wouldn't impact spray pattern etc?

Is it highly unlikely to think that the head might have been corroded/damaged/cracked from poor combustion in cylinder 3?
If mileage is genuine it's only 60k as it's a camper.

I don't really want to go taking the head off now, not something I've done before

[metalworker0]

i say .. I don't know what's going on

is it possible that an engine reconditioner / machine shop, has put some sort of insert / sleeve in there . like valve guides, cause i see the look of brass.

i suppose you followed advice above and wrapped tape around the reamer ..

all the best.mark

[therightangle]

Yeah I wonder...

The hole diameter is the same as the others, and the seat height didn't start out as any different before reaming.

So If they did put an insert in there I guess it looks like a good fit... But the reamer filings still appear to be silver/aluminium.

Yes the reamer has been a perfect fit in the bore with tape since the mention of it above, thanks.

I guess it's not a good idea to use a wider copper washer that would span across the full width of the hole, as it's likely to have more space under it than the original/genuine washers which seem to have only a narrow 1+mm ring width of contact with seat....?

[trnx]

A hole is reamed. A face is cut.
Chatter can be caused by the unit or and the tool not being firmly held in place, a damaged tool, a face with hardened areas, debri.
The injectors need to be at the same height above the pistons at TDC. The measurement needs to be accurate pos' to within 0.003".

The face may need to be ground to remove the chatter. There are small disc pads that could to it. The face needs to be at 90 degrees to the hole.
There'l be a tolerance of that 90 degrees. Taken up by the copper washer.

That which needs to be done on the head is likely to be costly - if done by a skilled machinist who needs to be familiar with that type of work.
DIY can be done - you need to be aware of that which is required.

Do you intend to DIY? Are you going to take it to a skilled machinist?

A DIY way could be to use steam joint compound between the annealed copper washer and the head. The depth of the injector nozzle (the face) needs to be determined first. A suitable vernier could be used from a common data to all injector bodies/face.

There's more than one way of achieving such a measure.

[anynamewilldo]

Did you manage to get this sorted in the end?

[therightangle]

Just as an update, I didn't see much difference when put back together with new washers and clamp bolts and upgraded clamps all genuine.

I was hoping for less blowby and maybe more power. I did widen one or two of the copper washers inside diameter, as they weren't fitting over the injectors. I assumed I'd be ok as the clamping down of the injectors would be enough to seal on the looser washer but in hindsight maybe I should have tried to sand the injector body more to get the washers on, and keep washers tight to injector body?

I thought I was down to bare metal injector body but there must have been some carbon still left on them I guess, even though original washers came off easier.