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Rocker oil starvation! eeeek!


haggis
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Hello, can anyone help me on this one, got a GT6 mk3 engine in a Mk1, its not playing nice at the moment. I have just replaced the rocker shaft assembly with a completely new one as the old one lacked lubrication at the front of the engine and 'cooked' the other day. new assembly installed, started her up ran great, got hot, ran like a bag of spanners. It would appear I have absolutely no oil coming up to the rocker for lubrication, I have  no intention in fitted one of these after market external feeds, but was wondering if anyone had any idea where the most likely place the blockage would be? I have removed the oil cooler feeds and emptied this out, i have also removed the complete oil filter & housing and both items are clear and had oil in them. I removed the 3 no external plugs to the gallery first and there was no oil coming out of them at all? Now the car hasn't run for a week or so, should I expect to find oil in the gallery at all times or should I expect it to be empty as the oil has dropped into the sump? Have removed the screw out of the rocker assembly and squirted oil in, this fills the shaft and runs out the back of the head via the plug to the rear. I'm thinking catastrophic failure of the oil pump, or a blockage in the engine , but it starts with great oil pressure reading!

I had just done a flush and put new oil & filters in after the first rocker failure, and I did pull out 2 no tiny 'O'rings from under the rocker cover on two occasions that were completely in tact. 

I'm puzzled about where to start looking really, any ideas?

 

Thanks

Hag

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The oil to the rockers is fed through a slot cut in the rear cam journal, this reduces the full pressure to the rockers as it only gets asquirt thro for each turn of the camshaft

this interupted feed passes up a drilled passage through a small hole in the head gasket and up a drilled hole thro, the head to the rear pedestal.

 

there, s a threaded plug on the rear of the head have you checked here,?

 

its possible someone has used sealer on the head gasket to seal the habitual seapage

and this is blocking the feed route.

 

if you have good oil pressure in the main bearing supply gallery this would seem the likley culprit

 

if you remove the rear pedestal its possible to feed a stiff wire down the head drilling,

 

if you add the dreaded external Do seriously restrict the flow by blocking the banjo bolt

with a 1mm or less drilled plug

 

you dont want full flow in the rocker zone, or starve the bottom end

 

 

pete

,

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Hi Pete, thanks for the early reply, I have checked the head rear thread and forced oil through the rocker which flowed out at this point, which I assumed to mean there isn't a blockage in the head. Any idea whether the gallery should have oil in it after left not started for a week or two? I have looked at both sides of the story for the external rocker feed and decided this is not a good option, so no intention of doing this although it would appear to be the perfect solution.  I think maybe the best solution will be to take the head off and blow all passages out, but I'll give the wire trick a go.

 

Thanks

Hag

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Hag,

As you can see more easily if you have the head off, this oil gallery is made up of three drillings:

Up from the face of the cylinder head.

Across from the back left corner.   This one is sealed with a short bolt and copper washer.   Make sure the bolt isn't too long!

Down from the top of the C/H.

 

If you have taken that bolt out and squirted oil into that, and it appears at the rocker shaft, then that part of the gallery is fine.    It can get blocked where the foot of the rocker pedastle meets the head, esp. if someone uses gasket sealer.

If you aren't getting oil up to the rocker in use, and given that you had an oiling problem before you replaced the shaft, then the blockage must be in the lower drilling.

As  Pete says, that may be blocked by overuse of gasket sealer.    You can't get a wire around the corner from the middle drilling, so I'm afraid it's head-off time.

 

An external oil feed is a bodge that would get around this problem, but again as Pete says you must fit a restrictor.   A copper disc, cut from a piece of central heating pipe, with that tiny hole drilled in the middle can be inserted into one of the connectors and will still seal.    But that hole must be tiny!    A 1mm drill turned by hand, from both sides until you can just see a point of light through it will be right!

 

John

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Hi John D, thanks for the reply, you got me thinking :huh:(i think this is a puzzled face?) how long is too long for the bolt to the rear of the head? I've noticed there is two copper washers on it and wondering if the idiot who owned it before has put a longer bolt in! In my mind when I removed it I did think it seemed long or the possibility it might be long, mine has 10mm of thread past the copper washer, any idea if this is too long? ultimately I think the head will need to come off, but just imagine if it was just a bolt that was too long!.

 

Thanks

Hag

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Hi John D, thanks for the reply, you got me thinking :huh:(i think this is a puzzled face?) how long is too long for the bolt to the rear of the head? I've noticed there is two copper washers on it and wondering if the idiot who owned it before has put a longer bolt in! In my mind when I removed it I did think it seemed long or the possibility it might be long, mine has 10mm of thread past the copper washer, any idea if this is too long?

The bolt should a 5/16" x 1/2", so if you have 10mm past the washer, sounds about right.

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HI Pete, yes run and driven 15miles, lifted the cover off and it looked and the front 3 sets of rockers were completely grey. 

I don't know if anyone has any experience of Kent cams, are there any known problems with the oil pick up to the rocker??

Clutching at straws really I know they are very well engineered product, I'm guessing the head needs to come off.  :(

 

Hag

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Hag

 

I suspect the clue maybe in the fact that you have found small o-rings.

 

Do you know the history of the engine??

 

I wonder if the car had an external feed at some point (properly, as in the passage in the headf was blocked with a grub screw), someone tried fitting o-rings to limit oil consumption, and then a later owner removed teh feed.

 

Possible???

 

Fit a feed with a limiter.

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Hi Scrapman, no don't know history of engine, have no idea if it had a external feed, as there was a little bit of oil in the original rocker I'm assuming I blocked it further with the flush. Bottom line the heads coming off tonight! and if i can't find anything the sumps coming off tomorrow! It will be an interesting voyage of discovery to see if the previous owner was a complete Numpty or not. I was really hoping after 37 years of maintaining my lovely 1600 vitesse that my next purchased one would require nothing but driving and a bit of routine maintenance, but it is a Triumph, and done to someone else's standards, I should have known better. But it is awesome looking & sounding can't wait to drive it for more than ten miles before it breaks down.

 

Thanks

Hag

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Hi Pete, normal kind of 60psi driving dropping down to 20psi when warm for tick over, but I think this is a blockage. I've taken the head off and it looks rather good, I will give it a good squirt through and hopefully shift this blockage.

 

Thanks

Hag

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as said the feed is from a slot in the rear cam journal so it only links the bearing supply to the output port in the bearing when the cam rotates to align the two

 

if the cam is in a 'closed' position the supply is shut off, so no poking proding will prove much

 

if you have small air feed or compressor you could pressurise the main gallery and turn the engine till the cam lines up the port and slot and air will escape

. a lot cleaner than oil everywhere.

 

the rear cam journal bush may have rotated in the block and closed off the feed.  some shells have a groove around the back face to elliinate any positioning 

 

but this is an area for investigation...   just to prove the idea is working  .....

 

Pete

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A few posts above you say no oil to teh front 3 sets of rockers? does that mean you do have oil to the rear 3 pairs?? I am getting confused!

 

Do not rely on a new rocker set being OK just because it is new. It may be worth investigating the shaft etc, I think you can remove the end caps?

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Hi Pete & Clive , thanks for your responses, rocker completely dry not just front end ones, I will inevitably take the shaft apart and have a good look when I start putting back together. I'll have a go at moving the cam and seeing if I can get the holes to align. Do you know, and this may be silly question, but can I turn over the engine with no head on to see if the pump is pushing the oil up through the engine block? or will I cause damage?

 

Hag

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Turn away , its no problem, use starter or by hand or in gear and push

 

it just goes round and round , cant hurt anything

 

the cam journal should have slot milled few mm wide and about 12mm long

like a saw cut across a sector

 

you cant see this as fitted, needs cam out to see this, but good cranking should show up a flow from the

hole in the block

 

if you get oil pressure in the gallery cranking but nowt out the hole then its time to pull the cam

pete

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Well I tried turning it over on the starter but no oil out of hole in the block! :( I did try compressed air down through the hole into the engine and the tone changed as I turned the engine over by hand on the crank, which I would assume means that the cam groove is working, but no oil. Is this because there is no pressure build up to help circulate around the engine?i.e the head is removed and the bowels of the engine are open through gaps between the cam followers for the oil to drop down to the sump? or am I talking absolute nonsense?

I think there is only way to truly tell and that is to strip it all down, cam, sump, pump an all! Any advice welcome.

 

Thanks

Hag

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Thought about remove the dizzy and drive drive gear and turn the oil pump with a drill.

?.. get the pressure to show a few psi on the gauge , turn engine to align cam oil slot and see what turns up from the feed hole in the block,

 

just an idea

If you getva reading on the gauge then the pump is pressuring the gallery

which is where the switchband gauge take off is fitted

Pete

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  • 2 weeks later...

HI Pete, thanks for your response, I decided to take the sump off in situ before I read the message. What a job, but so much easier if you take the steering rack out, why do they make the steering rack 'U' bolts so long, I'm cutting mine down on the way back in. I had some grey sludge in the sump (expected) although a bit gritty and a really good oil pump, which was all easily within tolerance and lots to go. I guess the question is where do I go from here? I've found nothing wrong so far, air passes through the hole down to the cam when I rotate it, air passes through the gallery into the sump? I was thinking as I've gone this far to remove the Cam to check the oil grooves as I have a leak in the front cover oil seal. Any suggestions of where to blow air next? or any suggestions generally? I think in hindsight I should have primed the rocker shaft with oil through the little retaining screw hole before proceeding (what a numpty) but I assumed it would fill up quickly from the pump, but I'm guessing it wouldn't have been long before the oil ran out.

 

 Thanks Hag 

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where to blow air sounds like a thread for the old age post  !!!

 

I guess having got this far pull the cam and check the rear bush and then youve covered just about everything and could be chasing a white elephant

 

but you will have peace of mind thats its all in a known state 

 

you had good oil psi , it just wasnt showing where you need it there's only the cam /bush/slot between the main gallery and the rocker pedestal

this is all a little 'odd'

 

time for strong cuppa.

 

getting the sump back can be more of a fiddle than removing ....make a big swear box 

 

let us all know what happens next

 

Pete

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Thanks Pete, I think the swear box could probably pay for a professional rebuild already! Sometimes you kind of know what to do but its reassuring to find people with more knowledge to help for guidance, and thats what this forum is for, I hope one day to be able to dispatch some of my Triumph wisdom on to others too. 

I'll let you know what happens.

 

Thanks

Hag

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  • 3 weeks later...

Well I eventually got around to pulling the cam, a little bit too much end float but cam in great condition, with the benefit of a new looking pulley and a double timing chain too. Now when I stared down cam hole I noticed a big blob of black stuff about the 2 o'clock position on the rear journal, I think I've found the culprit! with some persistant air blowing I think I've cleared the blockage. Its difficult to see/access with the engine still in the car, so stuck some oil into the rear gallery access hole, fired some air behind it and hey presto, a perfect squirt of oil into the rear journal. RESULT!

 

Engine starting to go back together now, still got me fingers crossed It works, sump gone on easy with the rack removed, haven't fitted the rack yet but should be easy if I cut the 'U' bolts down.

 

I'm thinking, if all this doesn't work (trying not too be negative) I will fit a restricted rocker feed kit as a temporary measure so i can still get some summer triumph fun in, and whip it out next year. It would appear from the previous owners invoices that one was bought some time ago, not sure if it was ever fitted. Is there any way of telling?

 

I'll let you know how it goes.

 

Thanks

Hag

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yes there will be a  flexi piperuns from theoil gallery or tee off the pressure switch and runs up to the pluged tapping on the back corner of the head where you tried blowing oil from

 

if you fit one restrict the banjo bolt by pluging and drill the smallest possible hole  even a 1mm is s bit big 

pete (on hollls using a snail \pc in the hotel while ruddy bingo is in operation.... dont ask !!!!!

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Sounds like your having a great time, can't find any evidence of flexi pipe runs or tee off the pressure switch, maybe it was for another car I often buy bits for my two cars together.

 

Enjoy your holiday.

 

Hag

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