Technical valve adjustment tricky?

[ruinin]

I would like to get my valve adjustment done, but what I don't understand from a different thread, varesecrazy writes:

"If adjustments are necessary ( shimmed out) TRICKY = it could be £100 /£150".

I called a Fiat garage in the city where I live, asked about the price of the valve adjustment and they said if adjustment is necessary, they cannot trim anything, they have to replace shims. I later found out the shims cost almost nothing, about two UK pounds for one shim. So what makes the adjustment so expensive? The mechanic told me that people don't have this adjustment done in general bc it is too expensive...

checking the adjustment, half an hour work, then replacing cheap shims will last several hours? makes no sense.

 

[jrkitching]

I would like to get my valve adjustment done, but what I don't understand from a different thread, varesecrazy writes:

"If adjustments are necessary ( shimmed out) TRICKY = it could be £100 /£150".

I called a Fiat garage in the city where I live, asked about the price of the valve adjustment and they said if adjustment is necessary, they cannot trim anything, they have to replace shims. I later found out the shims cost almost nothing, about two UK pounds for one shim. So what makes the adjustment so expensive? The mechanic told me that people don't have this adjustment done in general bc it is too expensive...

checking the adjustment, half an hour work, then replacing cheap shims will last several hours? makes no sense.

An hou'r labour at a franchised dealer will likely cost £100 or so, plus the cost of the shims and a new gasket.

It's straightforward enough, but needs to be done carefully by a competent mechanic.

From experience, they don't need doing often unless something is badly wrong. Worth checking when you change the cambelt, and shouldn't add much to the cost if done at the same time.

 

[varesecrazy]

Its the Labour..at UK RATES..itll be as Quoted 100 plus Pounds Sterling.

Remove. Airbox. Camcover

Meaure clearances.
Remove camshaft.
Change shims.
Replace camshaft.
Crank engine..check clearances

Reseal cam cover also.

 

[ruinin]

Its the Labour..at UK RATES..itll be as Quoted 100 plus Pounds Sterling.

Remove. Airbox. Camcover

Meaure clearances.
Remove camshaft.
Change shims.
Replace camshaft.
Crank engine..check clearances

Reseal cam cover also.

Ok, Fiat in Prague charges a bit less for labour. How many hours does it take to do all the above including replacing the shims? Still if one shim is only a few pounds, it sounds like the most expensive is the labour.

I know a good mechanic with an old garage, no fancy stuff, do you think I can rely on such a simple garage mechanic, can he handle this job or will he mess it up? I have no idea if this job , this fire engine has some special needs or special tools are necessary. He charges about 10 UK pounds per hour.

 

[jrkitching]

Its the Labour..at UK RATES..itll be as Quoted 100 plus Pounds Sterling.

Remove. Airbox. Camcover

Meaure clearances.
Remove camshaft.
Change shims.
Replace camshaft.
Crank engine..check clearances

Reseal cam cover also.

I'd expect a main dealer would likely use the Fiat shim removal tools in preference to removing the camshaft, but for the DIY mechanic it's perhaps easier (and cheaper) to remove the camshaft as you suggest. A useful tip and one I hadn't thought of .

 

[jrkitching]

I know a good mechanic with an old garage, no fancy stuff, do you think I can rely on such a simple garage mechanic, can he handle this job or will he mess it up? I have no idea if this job , this fire engine has some special needs or special tools are necessary. He charges about 10 UK pounds per hour.

If he's genuinely competent, he should be able to do this.

Why do you think it needs the valve clearances adjusting?

 

[irc]

The actual task is pretty simple, and quite satisfying to do yourself. The biggest hassle is having a selection of shims to swap. A decent selection of spare shims can easily be £200, so not something most DIYers will have.

As long as there is no rush to get the engine back together (or your cover gasket will go again) then it is not a big deal to order only the shims you need, at perhaps £1.50 to £2 each.
If you re-use shims, check them with a micrometer.

Many garages don't seem to do bucket and shim tappets any more; some have even been known to tell customers that they have been checked and are OK without removing the cover. Magic? Telepathy?

Get prices from a couple of good independents if possible to make sure you're not being robbed.

 

[ruinin]

If he's genuinely competent, he should be able to do this.

Why do you think it needs the valve clearances adjusting?

well, he doesn't know tje fire engine, he thought this engine didn't need adjustment,

otherwise I thought the valve clearance control is necessary as I have done about 150 000 km so far and it has never been checked - the clearance

so the whole job including replacing shims should last 3 hours at most?

 

[ruinin]

The actual task is pretty simple, and quite satisfying to do yourself. The biggest hassle is having a selection of shims to swap. A decent selection of spare shims can easily be £200, so not something most DIYers will have.

As long as there is no rush to get the engine back together (or your cover gasket will go again) then it is not a big deal to order only the shims you need, at perhaps £1.50 to £2 each.
If you re-use shims, check them with a micrometer.

Many garages don't seem to do bucket and shim tappets any more; some have even been known to tell customers that they have been checked and are OK without removing the cover. Magic? Telepathy?

Get prices from a couple of good independents if possible to make sure you're not being robbed.

my mechanic would only order the shims needed, so I would basically only pay for the labour - I just need to know he can do the job, so far I have had good experience with him, he does things quickly, honestly and can fix things other mechanics didn't fix properly

 

[irc]

No reason at all why he couldn't do it. No different from someone doing it themselves, if he's never done it before.
Definitely worth him checking clearances properly anyway.
Plenty of information on procedure on forum or Google.
It is completely possible that you don't need any changes- have had a 1.2 with 98000 miles which didn't.
But also had 1.2 with 50000 which did.

 

[jrkitching]

It is completely possible that you don't need any changes- have had a 1.2 with 98000 miles which didn't.
But also had 1.2 with 50000 which did.

OHC engines are much less likely to need periodic tappet adjustment than the pushrod engines of old; my Mk1 Ka needed some attention every service, but at least that venerable old Ford engine was a simple single spanner adjustment.

If the clearance has opened up, you'll likely hear it on tickover when the engine is cold. But if it's closed up, which is actually more dangerous to the engine, you won't hear anything, which is why periodic checking is a good idea. Rule of thumb for me would be after 10,000 miles (or once you think the engine has fully bedded in) and thereafter every time the cambelt is changed.

Certainly it should be checked anytime you have the cam cover off for some other reason; it takes only a few minutes if you're in there already. Clearances are on elearn, you can find a copy in the downloads section.

 

[irc]

Yep. Clearances closing up pretty much impossible to detect without feeler guages, until too late to avoid burned valves. That's what concerns me about garages not actually checking them, but just ticking the box on the service sheet.
At least every cambelt change is sound advice, but I know quite a few FIRE-engined cars which have never had a cambelt but are more than 10 years old, or have more than 100k miles.

 

[ruinin]

So it seems the mechanic, if honest, can do the job, and there is info on Czech websites too, that info freaked me out a bit as it has detailed instructions on how "to turn an engine" but that is probably something every mechanic is familiar with...

 

[DaveMcT]

Generally the clearances close as the valve seats wear. Eventually the valves don't properly close and the seats get burnt by hot gas tearing through.

The last time I did an engine I could not get one of the shims needed so using a micrometer and diamond face oil stone I lapped the back face of another shim until it was the correct thickness. It took an hour or so. The shim has to be constant turned and checked for thickness. The faces MUST BE parallel.

That was DIY. Obviously it would be silly cost for a mechanic to do it.

 

[ruinin]

Oh well, oh well, I just called a garage that had excellent references as for Fiat servicing. I asked about their capability to do the valve adjustment and the mechanic told me that he tried to do that with his motorbike and failed and that the job is extremely tricky, that it is basically impossible to get the clearances right as you measure something when the engine is cold, then you finish the job and start the engine and the hot engine has different clearances from what it was when it was cold. He told me that most probably all mechanics will mess up this job and it would be better to leave it as it is and not mess up with the clearances at all. He said as long as there are no wrong noises, I am fine and as for burnt valves he said the cause is different and not caused by wrong clearances.

 

[ruinin]

It seems there are two planets, on one planet this job is extremely simple, on the other planet impossible. I called yet another garage this time very big and very professional and wanted to know their opinion. The technician told me that they never do this and refuse to do this and when I asked why he said he cannot tell me the reason.

 

[irc]

That's a bit worrying. I would try to find a better mechanic.

Most "apprentices" would struggle the first time, but thats because their training is not as thorough as it should be. Having done it once, they should be able to repeat easily.

It isn't particularly tricky, as long as you follow the instructions.
The instructions give clearances for cold engine (although some more esoteric engines are done hot, and the process is different).

Some engines can be done with minimal dismantling, some need more parts taken off. Either way, following the instructions for the correct engine type is essential.

It is true that some "mechanics" will mess it up. They should not touch things they don't understand unless they are willing to learn properly.

Burnt valves ARE caused by clearances being too tight. If in doubt google "valve seat recession" to read about the effects of valve clearances closing up.
Loose tolerance = noise.
Right tolerance = almost no noise
Tight tolerance = no noise + loss of power & eventual damage.

I learned how to do this working on Lotus engines a long time ago. First attempt was rubbish and took me 4 hours. Then a guy from the assembly line showed me how to do it properly. Second attempt was spot-on and took 15 minutes. (16 valves too!)
Of course having all the right tools and every possible shim readily available helped, but it's not complicated. Just methodical, and requires accuracy.

Get them checked anyway. Unlikely to be too tight, as wear normally increases clearances, but would be a shame to trash your valve seats through not knowing.

 

[irc]

It seems there are two planets, on one planet this job is extremely simple, on the other planet impossible. I called yet another garage this time very big and very professional and wanted to know their opinion. The technician told me that they never do this and refuse to do this and when I asked why he said he cannot tell me the reason.

Get your local mechanic to check the clearances. If they are within tolerance then nothing needs to be done at the moment. Just needs some feeler guages and normal tools.

If you have any which are outside the given figures, then you will need to decide whether to get your local guy to do the work, or keep trying garages until you find a good one.

I've got a friend from near Prague who may know a good garage he has used who can do the job. He's not back until January but I will ask him next time I see him.

 

[ruinin]

Get your local mechanic to check the clearances. If they are within tolerance then nothing needs to be done at the moment. Just needs some feeler guages and normal tools.

If you have any which are outside the given figures, then you will need to decide whether to get your local guy to do the work, or keep trying garages until you find a good one.

I've got a friend from near Prague who may know a good garage he has used who can do the job. He's not back until January but I will ask him next time I see him.

Thank you for those ideas, I also thought that having it checked cannot mess up anything. Are the figures of the clearances really that tiny that it is difficult to find the right size shim? Good to get a good tip from a friend who knows a competent mechanic near Prague.

 

[jrkitching]

It seems there are two planets, on one planet this job is extremely simple, on the other planet impossible. I called yet another garage this time very big and very professional and wanted to know their opinion. The technician told me that they never do this and refuse to do this and when I asked why he said he cannot tell me the reason.

This is one of those jobs that is actually easier for the home mechanic than a professional garage.

Cold means just that. You shouldn't try to do this on a warm engine, so that means leaving it to stand overnight and then checking before starting the engine; hardly practical for most garages.

The running clearances are small but the shims are much thicker. There is one shim for each valve; if any need adjusting, the shim is changed for one of a different size. They can be bought in a range of sizes as necessary; franchised dealers and those specialising in the marque should have a complete set to choose from, but you can buy them individually on the 'bay. On high mileage engines the shims themselves can wear, so you need to check them with a micrometer rather than just relying on the markings. Sometimes if there are a number of valves out of adjustment, you can reuse existing shims in different positions; careful measurement of both shims and clearances is necessary, as well as the ability to do some basic arithmetic.

If you remove the camshaft to change the shims, you need to check everything again after refitting it; if you use the special shim changing tool to do it with the camshaft in situ, you only need to check what you've changed.

Again this is awkward for the small independent garage as they likely won't have easy same-day access to the necessary shims if one needs changing. I can understand why many are reluctant to take on this kind of work.