changed rocker arms and no compressions

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Re: changed rocker arms and no compressions

Postby tinakersting » 02 Feb 2018, 19:35

tinakersting wrote:
T25Convert wrote:
tinakersting wrote:[quote="T25Convert"][quote="itchyfeet"]Dare I suggest the mechanic could have not centered the pushrods and this can cause damage I have been told.


Not centering the push rod makes it around 5mm longer - I know as I managed to do it (more than once). If you wind the adjuster screw all the way out, the valve is still open as the push rod is long enough to still operate the rocker a little.

With the screw in a nominal 'two turns' I suspect it would hold the valve open wide throughout the cycle (giving zero compression).

It may or may not lead to damage, depends what is done next. Spinning it on the starter might cause a bit of valve-piston interaction.

However, if the mechanic is messing around trying to work out valve lash, then he may have observed the never closing valves and assumed that this is because the valve seats have regressed or valves stretched (hence his 'tight valve' diagnosis) rather than the push rods not seated.

I'd definitely want a second opinion.
Well it seems that the rocker arms on the side of the engine that have not been changed have damaged valves due to the rockers being too tight and there is some compression on the side where the nut fell off but it is low. The mechanic says if he has to renew the cylinder heads on the side with the damaged valves it will mean the lower half of the engine will have undue pressure on it so that would need to be rebuilt. He had quoted a sum of three thousand pounds to recondition the whole engine. He dosent do log though so even more to get that reinstalled we are very sad


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I think you might be being taken for a ride.

Did it run okay before the nut fell off?[/quote]At least taken for a ride is transport of some kind!
The thing is I am not mechanically minded at all we have learned the hard way that owning a t25 if you are not a mechanic or a hobby enthusiast IS expensive. Either that or none of the various mechanics we have used have been very interested in doing a decent job
The jist of this latest episode is that two weeks ago as I was shutting the engine off having driven from leiston to lowestoft my partner noticed a rattling noise never previously heard coming from the engine. Not knowing if we were causing Any damage and not wanting to chance any further damage we called the rac.
The chap used his long screwdriver as a stethescope(old school apparently) and after removing the driver side rocker cover the nut from one of the adjuster screws fell out onto the tarmac.
We were recovered to a garage in norwich.
When the mechanics inspected the engine they told us that the rocker adjusters had been left too tight by the person who had last adjusted them and some of the rocker arms were damaged and needed replacing. THEY were not able to source the parts.
I asked on the forum on Sunday and a member offered a compatible set complete which I took to them on wednesday
BY Thursday they reported that having changed the rockers on the side that cast the nut there was no compression in ANY of the engine valves.We found this hard to believe. Prior to the nut shedding we had never had a problem with power.
Today the mechanic says that the valves on the other side have been damaged by the too tight rockers and one valve is even in danger of falling down through the damaged collar which has been damaged over time. HE SAYS if he reconditions this top part of he engine it will more than likely cause the lower untouched side of the engine to fail fairly quickly hence he suggests he totally reconditions the whole engine or we purchase a newly reconditioned engine which he would put in for about three thousand pounds.
We do not know what to do. A member suggests a second opinion, are there any vw mechanics who know their t25s in Norwich who we could have the van transported to to give us that second opinion?
THIS mechanic has given a lot of time to us this week but has no other practical options for us.

Sent from my SM-G955F using Tapatalk[/quote]You suggest we are being taken for a ride but not why? Is it rubbish to suggest that rebuilding the head of the engine is not sensible/ will cause an imbalance therefore it should be all or nothing?

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Re: changed rocker arms and no compressions

Postby AngeloEvs » 02 Feb 2018, 20:03

May be too far for you but, following all the recommendations on this site, I took my van to campershack Nr Grantham. I am Nr Downham Market and it is a little over 60 miles. Very impressed, Andrew listened to my engine and his diagnosis was proved correct and the engine now being repaired as you can see on campershack facebook. Give him a ring, he knows his VW that for sure.
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Re: changed rocker arms and no compressions

Postby 937carrera » 02 Feb 2018, 20:09

OK, so you have limited mechanical knowledge - that can make it harder to help as well, let's see.

There are a number of things here that don't make sense to me

  • The engine was running fine, until you heard the rattling - was there still decent power
  • You were recovered by the RAC to a garage - is it this garage who are doing the work, do they have experience with T25 or other VW's ?
  • "The mechanic says if he has to renew the cylinder heads on the side with the damaged valves it will mean the lower half of the engine will have undue pressure on it so that would need to be rebuilt". This makes no sense to me, removing / replacing heads without a full rebuild is regular practice. That said you may have misunderstood what was being said.
  • How come there is apparently no compression on the side that didn't have a faulty rocker, yet the engine was running OK before

That said, it is easy to make accusations without knowing the full picture, having seen both sides of the argument at times, and there's plenty of commentary already above about badly adjusted tappets causing problems.

Adjusting tappets badly can also actually create a lack of compression......

Can you get your regular mechanic (one that you trust) to make a visit to the garage - I see that you are asking for recommendations, so maybe you don't have one.

I would be asking for a leak test to be done to confirm where the actual air leak causing lack of compression is coming from. A leak test / leak down test is a static test that puts compressed air into each cylinder in turn to get a reading of how much air is leaking as a % and then you can listen to where the air is going to atmosphere to determine if the problem is inlet or exhaust valves, piston rings etc.
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Re: changed rocker arms and no compressions

Postby tinakersting » 02 Feb 2018, 20:09

AngeloEvs wrote:May be too far for you but, following all the recommendations on this site, I took my van to campershack Nr Grantham. I am Nr Downham Market and it is a little over 60 miles. Very impressed, Andrew listened to my engine and his diagnosis was proved correct and the engine now being repaired as you can see on campershack facebook. Give him a ring, he knows his VW that for sure.
Thanks I'll give him a ring tomorrrow

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Re: changed rocker arms and no compressions

Postby bigherb » 02 Feb 2018, 20:14

The engine would not have been running if there were no compressions. Losing a nut from the rockers does happen but normally does not do any damage especially as the engine was still running and presumably apart from the noise you didn't notice any difference with the engine and certainly would not cause a problem with the rockers the other side. So we are back to has he done, or doesn't know how to do the job correctly or is having you on. I really think you need someone else to look at it as from what you say some things aren't tying up.
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Re: changed rocker arms and no compressions

Postby tinakersting » 02 Feb 2018, 20:16

937carrera wrote:OK, so you have limited mechanical knowledge - that can make it harder to help as well, let's see.

There are a number of things here that don't make sense to me

  • The engine was running fine, until you heard the rattling - was there still decent power
  • You were recovered by the RAC to a garage - is it this garage who are doing the work, do they have experience with T25 or other VW's ?
  • "The mechanic says if he has to renew the cylinder heads on the side with the damaged valves it will mean the lower half of the engine will have undue pressure on it so that would need to be rebuilt". This makes no sense to me, removing / replacing heads without a full rebuild is regular practice. That said you may have misunderstood what was being said.
  • How come there is apparently no compression on the side that didn't have a faulty rocker, yet the engine was running OK before

That said, it is easy to make accusations without knowing the full picture, having seen both sides of the argument at times, and there's plenty of commentary already above about badly adjusted tappets causing problems.

Adjusting tappets badly can also actually create a lack of compression......

Can you get your regular mechanic (one that you trust) to make a visit to the garage - I see that you are asking for recommendations, so maybe you don't have one.

I would be asking for a leak test to be done to confirm where the actual air leak causing lack of compression is coming from. A leak test / leak down test is a static test that puts compressed air into each cylinder in turn to get a reading of how much air is leaking as a % and then you can listen to where the air is going to atmosphere to determine if the problem is inlet or exhaust valves, piston rings etc.
It was running fine before the nut came off ,he did suggest that it wasn't a good idea to just rebuild the top half of the engine, the side that had all it's nuts he says has damaged valves BUT was running fine prior to incident we don't have a mechanic we can trust currently and I'll suggest the pressure testing for sure. It doesn't make sense to us either

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Re: changed rocker arms and no compressions

Postby tinakersting » 02 Feb 2018, 20:19

bigherb wrote:The engine would not have been running if there were no compressions. Losing a nut from the rockers does happen but normally does not do any damage especially as the engine was still running and presumably apart from the noise you didn't notice any difference with the engine and certainly would not cause a problem with the rockers the other side. So we are back to has he done, or doesn't know how to do the job correctly or is having you on. I really think you need someone else to look at it as from what you say some things aren't tying up.
Thanks we have a suggestion for a recomended chap in Grantham we will have to contact him and if he is willing try to flatbed it there from norwich next week

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Re: changed rocker arms and no compressions

Postby 937carrera » 02 Feb 2018, 20:47

tinakersting wrote:It was running fine before the nut came off ,


So unlikely there was a compression problem at that point

he did suggest that it wasn't a good idea to just rebuild the top half of the engine,


I wouldn't agree

the side that had all it's nuts he says has damaged valves BUT was running fine prior to incident


Doesn't make sense given the answer to question 1

we don't have a mechanic we can trust currently and I'll suggest the pressure testing for sure. It doesn't make sense to us either



Don't bother with the leak test. Use the guy who has been recommended, don't waste more money with the unknown garage and get prepared for an argument about the size of the bill when you decide to take it elsewhere
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Re: changed rocker arms and no compressions

Postby T25Convert » 02 Feb 2018, 23:29

^ what these lovely people have said.

It was running on four cylinders. To do so badly they needed some low compression. To do so well and drive nicely then you had decent compression.

Nut falls off adjuster on one rocker, so you lose one cylinder. Three still work fine. At this stage you may need a new rocker (or not) but probably nothing else.

RAC man takes you to garage.

Garage fiddles, and now you have no compression and nothing works like it should. So rather than fixing the issue it is now much worse. Now you apparently need a new engine.

Now, there may be wear and tear on either side that needs fixing to return it to perfect, but it was working, and provided the adjuster issue is fixed, it should t need anything else doing to it to return it to the condition it was in that you were happy with.

It might all be genuine and above board, but it doesn't make sense as it stands.

Get a specialist to have a squint at it to confirm.
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Re: changed rocker arms and no compressions

Postby ajsimmo » 03 Feb 2018, 09:14

Hi, sorry to hear of your woes but I wouldn't be able to fit you in until June now, as we're fully booked.
The lack of compression after work on rockers can be checked by backing all adjusters off to just touching, then test for compression. You might find it magically returns...

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Re: changed rocker arms and no compressions

Postby 937carrera » 03 Feb 2018, 10:04

Good people are always busy :)

I had a quick google for you, there's a couple of names in this thread

http://www.volkszone.com/VZi/showthread.php?t=503063

I can recommend someone in Leicester, but that's probably a bit far, and he is always busy too
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Re: changed rocker arms and no compressions

Postby 937carrera » 03 Feb 2018, 10:44

Just noticed you're actually one of the Southern Folk, rather than the Northern Folk :)

Another search produced http://www.volkszone.co.uk/VZi/showthread.php?t=497426

Simpsons came up on my initial search and Rackhams is mentioned on EarlyBay, but you need to be registered to see threads (or look at a cached page). I don't know either, I suggest you give them a call
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Re: changed rocker arms and no compressions

Postby itchyfeet » 03 Feb 2018, 11:44

There is somebody reasonably local who is very experienced, he usually hangs out on facebook WBX group but I sent him a link to this thread, he says he will contact you.

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Re: changed rocker arms and no compressions

Postby tinakersting » 03 Feb 2018, 12:00

ajsimmo wrote:Hi, sorry to hear of your woes but I wouldn't be able to fit you in until June now, as we're fully booked.
The lack of compression after work on rockers can be checked by backing all adjusters off to just touching, then test for compression. You might find it magically returns...

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Thanks you are busy![SMILING FACE WITH OPEN MOUTH] it is so heartening to have all these good people's knowledge!

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Re: changed rocker arms and no compressions

Postby kevtherev » 04 Feb 2018, 08:03

It doesn't get any easier reading posts like this.
After 13 years a member this sort of thing is still upsetting.
I do have such sympathy for you.
As you say being a victim of nievity is hard.
I'd like to see this damaged rocker or any pictures of the so called issues.

The rest of the van can be looked after by any garage.
The engine and drivetrain is however not something to be left to the great unwashed of garages.

These unique engines are quite robust and do run well into the 200,000 mile bracket.
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