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oil feed


Guppy916
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My car is a MK3 GT6 with a 2.5 lump, 80 miles since a full restore, the engine had a complete rebuild with a new oil pump, crank regrind new shells, I suffered low oil pressure 20PSI when hot after 30 miles, I got the car home with no engine noise,

right engine out, gear box still in car, what a shite job. just because i didn't want to to take the tunnel out! 

with the engine striped  the cam is totally knackered, Journals 1&2 show signs of scoring, 3&4, totally buggered. I shall have to get a new cam and a set of cam bearings, 

the big ends look okay no damage but I shall fit new one's anyway, The mains are still in I haven't removed them yet, 

I also noticed the lack of oil in with the timing chain which was almost dry, The oil is being filtered so i can see what debris is in it,  I haven't checked the oil pump yet but I shall replace it anyway, any body know where I can buy a quality pump ?

I think I read on our old site (Club Triumph)  that some people enlarge the oil ways to the cam, but I have no way of checking that now, Sorry I can't post photo's on this new site, ( Club Triumph)

Also the thrust washer on the crank shaft is showing a lot of wear, I know when I rebuilt the engine the end play was very tight 4 - 5 thou, but thats what the book says to set it too, now its as slack as a yak ! 

 so either the pump is fu=ked or ive suffered with blocked oil ways,

right the good news piston and bores look great, so new rings and that will do, after all the engine has only done 80 ish miles 

So where to buy a cam and bearings from ?? I don't want a Kent one, because a friends went pear shape after a few miles the lobes blue out ( is that the right blue)?

the photo shows where the cam got chuffing hot, the followers are fine, and the push rods are okay no signs of getting hot

 

advice please, ta guys

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For so much to get wrecked its got an obviuos lubrication problem, form a rebuild to destroy itself it must stem from the base supply 

And the pump and its drive must have some input, if the engine was ok for oil, pressure before the rebuild  I dont see how a rebuild can develope a blockage,  and for a cam to get that hot and seize when its got splash from the crank , and thrusts which only take load when clutched ,  one wonders was there enough or any  oil in the sump,  Or In the prv jammed  open ,  the gallery has been seriuosly starved 

What pressure was showing at the start of the drive??

Pete   (well the cats got me up early )

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The paint on the block seems to have blistered just in front of the dizzy where the cam runs

could this be a sign of things getting very hot in the cam bearing. I would also cut open the oil filter to see what you find in there.

I hope you wasn't running an external rocker feed as that may have robbed the cam of oil pressure. 

Sorry stating the obvious after reading all of your first post.

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Slight thread drift - The club offer reconditioned engines which from previous comments are carried out by Ivor Searle - The VITESSE Mk1/2 is quoted at £2677 - Does this price include the cylinder head refurb 

Has anybody used the TSSC services for reconditioned engines ?

Regards

Paul 

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complete engine is a complete rebuild, everything is checked , cleaned , ground, measured, torqued, tested , to high standards 

do you mean unleaded inserts ,  you need to ask ,i wont guess that one ,

but from a visit they do more than some OE manufacturers would , amazing controls and assembly criteria.

its not just a oily rag a quick grind and bore and a blow over 

 

 

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Post copied from CT.......

First question..... and it's a key one; does your block actually have cam bearings?  These were not standard fit on any of the 6 cylinder blocks, with the cam running direct in the cast iron. In order to fit cam bearings the block has to be line bored.  Finding places that can do this is not very easy as the block is quite long.  Do NOT believe anyone who says they can do it in two goes from either end!

If your block does have bearings (and I would be surprised if it does) then you can change them but I'd also be checking whether the oil holes in the bearings were lined up with the oil holes in the block and whether the bearings have been spinning in the block.

If your block has no bearings then the big worry is the state of the bores that the cam runs in and I fear they'll be shot - meaning you have no choice but to get the block line bored if you want to save it.

Will be interesting to see the state of the oil pump......it may well be chewed up now having had to swallow whatever debris was falling into the sump, but as it gave good pressure initially it may not be the original problem.  Cam bearings as an initial failure point is odd, especially if the crank bearings are still fine.  What cam are you running and what valve springs - is there any possibility that the valve springs are excessively strong or were becoming coil-bound?  This can overload the cam journals and cause them to fail and the resulting wide open tolerances then cause a drop in oil pressure.  

Have no theory on the thrust washers - presumably it's the one on the flywheel side that taken the brunt?  Were they fitted the right way round?  (awful easy to get wrong.....)

Any engine rebuild, and especially this one, needs total cleaning of all of the oil ways.  This means an empty block, all gallery plugs out and the distributor drive bush out (as it sits in the main oil gallery).  Then it's out with the carb cleaner, rifle brushes and elbow grease until you are certain they are all squeaky clean.

You might find this helpful

http://sideways-technologies.co.uk/forums/index.php?/topic/5712-competition-oiling-draft/  (oilway mods and external feeds not necessary on road engines)

Nick

 

PS solid bronze thrust washers from here  http://www.customthrustwashers.com/

 

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Pete

Nice to know you have visited the engineering work shop who are advertised in the club shop for engine rebuilds. Obviously not a cheap prospect but in the future us novices will probably require their services. Great to here about their high standards and thorough work. 

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thanks for all the input, In no set order, the cam  is ultimate Road, no cam bearings fitted, the engineering guy said there was no need as the bores were fine, oil pressure at the start was 50 ish PSI, yes I am running an external oil feed, I was under the impression with a high lift cam it was necessary, I haven't taken the PRV out yet or the mains, and the big ends show no signs of any wear, I have sent an email to Newman's for a cam and bearings, I shall be taking the block to http://www.ocservice.co.uk/services/lower-block, these guys machined the head and block on the rebuild and they are only 20 mins away, the springs  came from Rimmer's , A friend has mentioned that did I get carried away with the Hylomar thats a possibility, its also been mentioned have I got a saloon car sump pan on it and not a GT6 sump pan, could it be where the sump pan has been shaped to fit over the steering rack, stopping the oil flow to the timing chain via the bottom pulley "splash washer" ? I'm in need of all your help guys, thanks

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I fear the external oil feed that increases the flow to the rocker gear may have robbed the cam of its share of the oil.

Also depending on which sump you used with which dipstick would effect the working oil reserve in the sump

 as the oil level will change with the engine in the upright position.

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I'm not a fan of the external rocker feed myself and wouldn't consider one needed for anything short of the roller-bearing type of roller rockers.  However, I doubt it is to blame here.  The fact that your cam chain is almost dry suggests that little oil was getting to the top-end anyway as the chain is mostly lubricated by what is gravity returning from the front of the head and what squeezes out of the front cam bearing.

Hylomar/silicone blocking oil-ways.......... probably not oilways as such as anything that gets through the pump will be caught in the oil filter.  Might have partially clogged the oil-pump intake screen, though you'd have seen that by now I think.  Maybe oil filter itself clogged, but again, any decent oil filter should have an internal relief/bypass valve so the engine is not starved and it would take a hell of a lot of gunge to clog an oil filter in 80 miles anyway!

You need to look at the mains, oil pump and relief valve.  If all still seems good here I really think a careful look at the valve train re. lift and spring compression.  It would be really strange to kill the cam bearings before any BE/mains show any sign of harm due to lack of lube - they are all fed off the same gallery.  Front of the engine is furthest from the pump in flow terms.

Don't think the saloon sump makes any practical difference.  It is fair to say that the dipstick might not read dead right but I don't think enough out to make a difference.  If you put most of a 5L can in there and got much the same back - no issue.

Nick

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In fairness, you only get massive flow to the top end if the rocker assembly is very worn.  The tolerances between rocker and shaft are the ultimate control here.  Had there been massive flow to the top end then the cam chain would have wet not dry.  I do completely agree that where an external feed is used a 0.8 or 1mm restrictor (MIG tip?) should fitted in-line somewhere.

Nick

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Ah!  The dreaded external oil feed, aka Ye Spawnne of Ye Deville, the worst mod ever inflicted on long-suffering Triumph owners.

It has been part of my life's work to persuade the world that it is a figment, an hallucination, that pushing all the oil supply up into the rocker shaft is a Good Idea.   I thought that the message had got through, but sad to say, it clearly hasn't.     Some due diligence and research before fitting would have shown you at least that there was some doubt about its advisability.

     It can be done, if a restrictor is inserted in the line.  That restrictor should have an orifice that is less than 1mm in diameter, or it will rob the oil flow.   That shows you how bad this idea is.     Sorry, Guppy, but that's the truth.

JOhn

 

PS I see Pete has the same view of this satanic progeny, and that Young Nick agrees about the restrictor.

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50 PSI doesn't sound high enough, but it would not have been low enough to have blown the engine at that stage. Driving from cold should be 70 PSI which drops to 60 PSI when warm. It sounds like things to come, so that caused a final drip in oil pressure. Hyomar can stick around the oil pump strainer, but you would see that when you strip down the engine.

Dave   

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6 minutes ago, JohnD said:

Ah!  The dreaded external oil feed, aka Ye Spawnne of Ye Deville, the worst mod ever inflicted on long-suffering Triumph owners.

It has been part of my life's work to persuade the world that it is a figment, an hallucination, that pushing all the oil supply up into the rocker shaft is a Good Idea.   I thought that the message had got through, but sad to say, it clearly hasn't.     Some due diligence and research before fitting would have shown you at least that there was some doubt about its advisability.

     It can be done, if a restrictor is inserted in the line.  That restrictor should have an orifice that is less than 1mm in diameter, or it will rob the oil flow.   That shows you how bad this idea is.     Sorry, Guppy, but that's the truth.

JOhn

 

PS I see Pete has the same view of this satanic progeny, and that Young Nick agrees about the restrictor.

Me too, Pete and John.

Dave

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Ray and I have been having a natter,

How much oil was in the sump? Just dreaming about the oil level effect of the angled saloon sump, what dipstick, does the rack hump hold back any oil drain,

Is there an oil cooler   ,

I see the pump is a gauzed filter , needs to be fully submerged,    we dont know the sump reserve capacity when running 

Do all these  with the oil feed add to the failure mode?

Pete

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Pete you just me to post this, Thanks once again guys, the point has got through 'Mr JohnD' some what late, but its arrived,  the external feed is off and in the bin! the mains are in perfect condition,  the PRV looks ok spring not broke, what else can i look for , Yes the thrust was fitted correctly, do I remember that some people when fitting the thrust drill and pin them so they can't fall out, views please. The large pieces are all soft so i think my fault it's Hylomar, the vary fine swarf and the circle bit I would say are from the cam, I have refitted the oil pump and taken measurements , the tip of  the pump almost touches the bottom of the sump, the pump filter was clean when removed, with the dip stick fitted & measurements taken again Full reads 40mm down into the sump, and empty reads 65mm down into the sump, the top of the oil pump filter is 100mm down & the bottom of filter 140mm down into the sump this sits 5mm off the bottom of the sump, when the engine is full of oil this level is 40mm from the sump flange, so the pump filter is covered all the time full & empty of oil, I checked the amount of oil drained 4.5L so the engine was full, 

David I was using running in oil I thought that was why the pressure was slightly low when hot, would you guys fit the external oil feed if it had the restricter fitted ?

No oil cooler fitted Pete I don't know if the wee hump stop any oil flowing through,

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It's not the external rocker feed nor the sump that have done this. If it was you'd see damage to the big ends and mains. Try shining a light down the camway in the block and look at the witness marks in the bearing bores - are they visibly oval?  Reckon the damage will be mainly on the bottom........

Nick

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That is hinting at coil binding or excessively strong valvevsprings.

i have a block that has done approximately 100 miles with oval cam holes and a totally buggered cam.

springs too strong. Came from a stock car I think, suspect they were trying to stop valve bounce at unpleasant rpm.

 

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