Oil spray pipe - how tight should it fit?

sladey · Post by **sladey** » Thu Jul 29, 2010 9:14 pm

Some of you will have seen the problems I've had with my engine recently which caused it (but not me) to miss CLM.

Basically the inlet rocker on No. 6 cylinder wore through the outer hard casing and the camshaft started wearing it away rapidly. In the process it took some metal off the cam, which in turn took some metal off the exhaust rocker.

It's in a local garage (on a recommendation and I was able to tow it there). They've replaced the cam with a good secondhand one I sourced (from David on IB who's having his engine rebuilt by Mike Bainbridge)

It's while trying to suss the cause of it that I need some help.

The most obvious cause would be a a blocked hole in the spray pipe. I think that's what lead to my engine rebuild in 2006. I've just checked the invoice for that and at the time they installed a new spray pipe, a new cam, and one (as in 'not two') new rocker arm.

We've checked the pipe today and oil squirted in will come out of all the holes - you need to blow to get it to come out easily.

So on the picture above Adrian (the owner of the garage) blew into the hole with the blue circle around it. Oil came out of all the spray holes fine.

However oil also came out of the gap between the pipe and it's housing (the cam carrier?) I've circled this bit in red. There's no hole there or anything, it just leaks out around the pipe.

My big question is - is this normal? Just to be on the safe side we're installing a new spray pipe anyway, which is now on order. Adrian was thinking of applying a bit of loctite around that hole to get a good seal - on the basis that oil leaking out of there will be robbing flow further down the pipe.

I don't know if this is a good idea or if the leak is normal or indeed if it caused/contributed to my problem. I'd welcome opinions.

As to what caused the problem, as the pipe itself is still spraying oil my theory is that the rocker on No. 6 that wasn't replaced in the last rebuild (some 40K miles ago) would have suffered heat damage at the time and was waiting to eventually wear through it's outer hardened shell - this happened to go through recently, aided, abetted, or caused by the leak around the pipe in the picture.

I'd welcome thoughts and opinions on this please (especially from the sage of the lakes) - am I talking rubbish? Is this seepage normal? would loctite be a good/bad idea.

Thanks advance for any help you can give

Cheers

Mark

Nick Moss · Post by **Nick Moss** » Thu Jul 29, 2010 9:52 pm

The spray bar is a non-interference fit into the cam carrier, but there should be zero leakage. An air line is giving maybe 120 psi, whereas the max oil pressure would be 80 -100 psi, so there is not a great difference there.

I have used an aerosol brake cleaner to check the spray bars, not sure what pressure that is but surely way below 80 psi! As I commented before you should remove both spray bars and clean them out as a matter of course having had the problems you have had. And is there is any sign of silicone sealer in there I would strip the engine to clean it all out.

impmad2000 · Post by **impmad2000** » Thu Jul 29, 2010 10:12 pm

I have some spare carriers, removed from the engine. If comparing these with the one from your car helps, then you are welcome to borrow them.

Tim

sladey · Post by **sladey** » Thu Jul 29, 2010 10:24 pm

Thanks Tim - might take you up on that - will let you know

sladey · Post by **sladey** » Fri Jul 30, 2010 10:49 pm

Just an update on this

Talked it through with Mike Bainbridge this morning. He said it is normal for some oil to come out around the pipe there shouldn't be much - I felt what was coming out was enough to cause a problem. I was concerned that when the pipe was last removed they'd enlargened the hole somehow and it was causing this leak. Decided to remove the pipe and first check if it was inserted the right way around, and secondly examine it for damage. If it was either of those things then a new pipe might sort the problem.

Adrian took the pipe out and confirmed it was in the right way around but that the walls of the hole with the problem looked like someone had tried to tap a thread into them - probably while trying to extract the previous pipe. This probably means the cam housing is knackered - this damage probably isn't enough to cause a serious problem straight away but the rebuild should have lasted more than 40K miles.

Mike has sourced a new cam housing and 4 more rockers for me (apparently 4 of the rockers aren't wonderful - not bad but not brilliant either) and is very kindly going to drop them off on Sunday on his way to a mates house. Mike's advice has been brilliant - very knowledgeable but also very practical.

The car will be with Adrian for a bit longer now but my daughter's bought a mini so I'll have something to drive around in.

Thanks for everyone's help. I realize that even doing this much work is a risk and the only way to guarantee success is to strip the whole engine, clean and rebuild but I simply don't have the money for that at the moment. Hopefully this flush and replace policy will work.

Cheers

Mark

Nige · Post by **Nige** » Thu Aug 26, 2010 10:03 pm

Any more news Marky Mark?

Barry · Post by **Barry** » Thu Aug 26, 2010 11:13 pm

Just what I was wondering earlier funnily enough: don't know why, just realised I couldn't remember where things had got to.

So .... ???

Lightweight_911 · Post by **Lightweight_911** » Thu Aug 26, 2010 11:39 pm

I think Mark's too busy having fun with his 'daughter's' (!) Mini to be bothered with the 911 ... wonder if he's let her drive the car ?

sladey · Post by **sladey** » Fri Aug 27, 2010 8:26 am

Sorry chaps

It's still in the garage being sorted. I know it's been a long time but that's more due to the garage guy (Adrian) going on a fortnight's holiday.

The new cam carrier supplied by Mike has been fitted now and Adrian is going to fit the new spray bar into it.

With the engine out we found a hole near the oil filler that would be just about impossible to get at with the engine in so he's going to patch that up.

In addition I've had a pair of Elephant Racing monoballs sat on my shelf for well over a year because I couldn't get the old ones out with the engine in - they've gone in as well - not a big job with the engine out.

Finally I had a call on Saturday (Adrian's back) to say my brake lines at the rear are badly corroded - he felt it could be an MOT failure - so I'm replacing them front and rear with braided ones.

I phone Adrian on Wednesday and the job is ticking along nicely - I reminded him I want the engine flushing out as well as we can - I know it's a risk not breaking the whole engine down and cleaning it but it's one I'm prepared to take - if it doesn't come off then I'll be doing the rebuild myself.

It's weird for me not having to worry about getting the car back TOMORROW! - having the mini to use is really convenient and it stops me putting pressure on Adrian. I'm hoping the bill won't be too big - there have been very few parts involved, and it's just his time in dropping the engine and rebuilding that part of it.

The Mini's fantastic around town - can keep up with anything, get into gaps, and pulls away nippily. However my journey to work involves a long stretch of 50MPH road - the mini's more or less at full stretch there - I certainly can't overtake anything.

I'm looking forward to getting back into porsche driving.

Having said that I've done a bit of welding on the mini and am about to do some more this week-end - this is all training for when the porsche comes back - I've got corrosion in a few places and am planning to sort it out myself a bit at a time. If I can just reach the dizzy heights of 'solid competence' in bodywork terms then I'll relax more about the porsche.

Had a bit of a saga with "da beast" (my Nissan 100NX) but I'll post that elsewhere

Cheers

Mark