eightinavee
Well-Known Member
Yes its lot different to a TDI,its chain driven OHC for a start,it uses Electronic unit injectors - which need their pushrod preload adjusting on reassembly.The only easier thing is that the valve clearances dont need adjusting as they have hydraulic lifters as a Rover V8 has.Its not such a straightforward job as a TDI,I wouldnt attempt it without the factory w/shop manual.
discomania
Well-Known Member
ormus said:
Its utter BS.
clutchdust
Well-Known Member
eightinavee said:
theres no need to touch the injector rocker shaft when taking the head off
eightinavee
Well-Known Member
There is if you have it pressure tested,skimmed and valves/seats done - which usually happens at independants.Are Franchised dealers still not meant to skim warped TD5 heads ?clutchdust said:
eightinavee
Well-Known Member
Back in the real world,Td5 heads get skimmed - on a daily basis.The only thing you need to be careful of is to maintain the valve face to head face dimension by maching back the seats.I think lots of members of the Federation of engine remanufacturers would laugh if you said it couldnt be done.LR said TDI heads should not be skimmed either,lots of people will tell you that corroded K series heads cant be Tig welded - they can,I've done it.
Lots of things would never get done in this world if people believe everything they are told at face value.Push an engineer into a corner and they will find a way out.
Lots of things would never get done in this world if people believe everything they are told at face value.Push an engineer into a corner and they will find a way out.
discomania
Well-Known Member
Indeed, a lot of people say "you can't" but often don't offer any proper excuss.
The more manufacturers tell you, you can't do, the more money they hope to make.
The more manufacturers tell you, you can't do, the more money they hope to make.
Allan Chambers
New Member
You can skim the TD5 head as with other alloy heads (within safe limits).
Rember to ensure you have the later steel locating dowels as opposed to the bendy plastic ones. If you remove the injectors, remember to keep them in exact order.
Regards,
Allan from LEGS.
Rember to ensure you have the later steel locating dowels as opposed to the bendy plastic ones. If you remove the injectors, remember to keep them in exact order.
Regards,
Allan from LEGS.
Out of interest, once you have skimmed the head to make sure that it's surface is flat and a good mate to the deck of the block, how do you deal with the camshaft bearings, for example?
I mean, a warped head is a warped head. The entire lump of alloy is no longer 'straight', so none of the bearings for the camshaft will now, for example, be true.
Do you bolt the head back to the block and line bore the bearings (which is how they were formed when the engine was orginally made)?
Or do you simpy yell 'yee haa' and hope that neither the camshaft will pick up on a bearing nor that the motor will be asked to last many more miles, minus its properly heat treated head?
I mean, a warped head is a warped head. The entire lump of alloy is no longer 'straight', so none of the bearings for the camshaft will now, for example, be true.
Do you bolt the head back to the block and line bore the bearings (which is how they were formed when the engine was orginally made)?
Or do you simpy yell 'yee haa' and hope that neither the camshaft will pick up on a bearing nor that the motor will be asked to last many more miles, minus its properly heat treated head?
Allan Chambers
New Member
Dear Disco 11.
Thanks for the reply.
This could take longer than the fox hunting debate!
We are merely discussing the merits of re-machining or binning the head and using a new, expensive unit.
It all depends on how severe your warp in the head is.
The manufacturers steer us away from re-machining the heads purely for commercial reasons.
The distortion from the head surface should not extend to the cam area unless it is really bad, in which case you should launch it into the scrap.
Kind regards,
Allan from LEGS.
Thanks for the reply.
This could take longer than the fox hunting debate!
We are merely discussing the merits of re-machining or binning the head and using a new, expensive unit.
It all depends on how severe your warp in the head is.
The manufacturers steer us away from re-machining the heads purely for commercial reasons.
The distortion from the head surface should not extend to the cam area unless it is really bad, in which case you should launch it into the scrap.
Kind regards,
Allan from LEGS.
eightinavee
Well-Known Member
I'll save Allan the trouble here,most garages simply remove the head and send it to the machine shop complete - they rely on them to strip,clean and test.A modern engine shop has lots of toys to make this possible - good ones rely on accurate tests to ensure they are not trying to repair a scrap unit,nobody wants to rebuild an engine that is going to come straight back.The cost of parts involved each time it is taken apart is also a major consideration.DiscoII said:Hi Allan
It's a good debate though innit?!
And if you took your head to be skimmed, would they bother (or even be able) to measure how straight the camshaft bearings were, given that the other half of them are still in the cam carrier back home in your garage?
So is that a yes or no to 'do you think they could or would bother'?
As somebody who sends a head away to get skimmed, hmmm, maybe every two weeks, don't try to teach granny to suck eggs, but answer the question.
My opinion is that a machine shop will simply skim the head if you ask them to, nothing more. I mean, what can you expect for your 40 quid?
In the case of the TD5 they can't check the camshaft bearings properly unless the head is bolted to the block because half of the bearing is in the head and half in the cam carrier. When the engine is manufactured, as I said before, the head is bolted to the block and the bearings are line bored, with the head bolts all torqued up properly to ensure that when the cam is finally installed, everything is subject to the same tolerances.
As I said before, when a head warps, it warps. To expect the face which mates to the deck of the block to warp and nothing else, shows either a lack of understanding of the laws of physics or simply a lot of wishful thinking. Granted the head may not have warped enough so that other components are now outside of their working tolerances - but how do you know?
As an aside, I would never send a head away unless I had stripped and cleaned it beforehand and to say that a gasket set is a major consideration belies that fact that the labour involved would be the major cost.
As somebody who sends a head away to get skimmed, hmmm, maybe every two weeks, don't try to teach granny to suck eggs, but answer the question.
My opinion is that a machine shop will simply skim the head if you ask them to, nothing more. I mean, what can you expect for your 40 quid?
In the case of the TD5 they can't check the camshaft bearings properly unless the head is bolted to the block because half of the bearing is in the head and half in the cam carrier. When the engine is manufactured, as I said before, the head is bolted to the block and the bearings are line bored, with the head bolts all torqued up properly to ensure that when the cam is finally installed, everything is subject to the same tolerances.
As I said before, when a head warps, it warps. To expect the face which mates to the deck of the block to warp and nothing else, shows either a lack of understanding of the laws of physics or simply a lot of wishful thinking. Granted the head may not have warped enough so that other components are now outside of their working tolerances - but how do you know?
As an aside, I would never send a head away unless I had stripped and cleaned it beforehand and to say that a gasket set is a major consideration belies that fact that the labour involved would be the major cost.
Allan Chambers
New Member
Dear Disco 11.
It all depends on the machine shop if they would bother. YES, they should bother. You should therefore go back to your garage for your cam bearings.
We have facilities to measure if the head is servicable, but this is where experience plays a big part.
Lets not loose sight of the fact that we are skimming the surface of the head to ensure a flat surface. Problems with the cam are a seperate issue.
Regards,
Allan from LEGS.
It all depends on the machine shop if they would bother. YES, they should bother. You should therefore go back to your garage for your cam bearings.
We have facilities to measure if the head is servicable, but this is where experience plays a big part.
Lets not loose sight of the fact that we are skimming the surface of the head to ensure a flat surface. Problems with the cam are a seperate issue.
Regards,
Allan from LEGS.
eightinavee
Well-Known Member
As Allan says, it depends on the machine shop as to wether they would check for cam bearing alignment.There are 3 machine shops in useable distance from me,2 would most definately check - the third probably wouldnt.I have used all of them,the job dictating who I use.The best one,(in my opinion) I did about 5 years sub-contract engine building and onsite warranty work for.Interesting stuff,and one of my early questions was about cam bearing alignment on a warped head - I was suprised how the head face was out,but the cam side was ok.Why scrap a head if it can be repaired satisfactorily ? As for cleaning the head before you send it in,you are wasting your time unless your engine shop is a rip off,a good engine shop is much better equipped with cleaning kit than your average "safety Kleen" tank/pressure washer.Whilst they are stipping the head they can often find the causes of failure that the mechanic didnt spot on taking it apart.Also different engines fail in different ways,a good shop will know not to bother pressure testing a Rover V8 head unless asked to by the customer.On a K series it would be commercial suicide not to.
When I mentioned the cost of a head set,it was to make the point that it doesnt end there,there are also head bolts,coolant,(most mechanics dont seem to like catching and reusing it)The cost of doing a job a second time is horrible to all workshop owners/operators - but most seem to grudge the parts costs rather than the lost labour,they would rather stay on in the evening to get the job done and back out.
If you send a head away once a fortnight you are also aware that they dont just get skimmed for warping issuses,corrosion and blowby erosion are just as common.I once Tig welded a 16v Honda head that had rotted away,about 50% of the head face ended up being weld - took about 2 1/2 hrs of welding.I thought it was a complete waste of time,but they skimmed it and did the valves/seats etc and it went back together after passing all their checks.The customer thanked us greatly as it was turned round in 2 days and less than 1/3 the cost of a new one.We never had a warranty claim on that head.
I have to ask why you find it necessary to ask all these questions if you are so sure of the answers and are doing so much engine work ? Are you not allowed into your engine shop or wont they answer your questions.In my experience they are all too happy to give guided tours and explain the various processes.
As for a good debate - I dont think so,this is a forum,the dinner table or the pub are the proper debating places.
When I mentioned the cost of a head set,it was to make the point that it doesnt end there,there are also head bolts,coolant,(most mechanics dont seem to like catching and reusing it)The cost of doing a job a second time is horrible to all workshop owners/operators - but most seem to grudge the parts costs rather than the lost labour,they would rather stay on in the evening to get the job done and back out.
If you send a head away once a fortnight you are also aware that they dont just get skimmed for warping issuses,corrosion and blowby erosion are just as common.I once Tig welded a 16v Honda head that had rotted away,about 50% of the head face ended up being weld - took about 2 1/2 hrs of welding.I thought it was a complete waste of time,but they skimmed it and did the valves/seats etc and it went back together after passing all their checks.The customer thanked us greatly as it was turned round in 2 days and less than 1/3 the cost of a new one.We never had a warranty claim on that head.
I have to ask why you find it necessary to ask all these questions if you are so sure of the answers and are doing so much engine work ? Are you not allowed into your engine shop or wont they answer your questions.In my experience they are all too happy to give guided tours and explain the various processes.
As for a good debate - I dont think so,this is a forum,the dinner table or the pub are the proper debating places.
Allan Chambers
New Member
To Eightinavee.
Well said! The pub is the best place for this type of discussion. Besides, after several pints everyone is a qualified engineer!
Regards,
Allan from LEGS.
Well said! The pub is the best place for this type of discussion. Besides, after several pints everyone is a qualified engineer!
Regards,
Allan from LEGS.
