2l air-cooled running problem

[Martynpfield]

Hello I'm in need of some help. I've had my t25 for about 2 year now and I've had lots of work done to it. This includes a new engine, clutch, carbs rebuilt plus many other new parts. The problem started after I had the carbs set up on the rolling road. Basically the engine will start and run on tickover but as soon as you try to drive it it has no go , it sounds like the choke is on when to try to rev it. It has done this in two occasions and it has cleared it self and driven ok after about 5 10 minutes . The last occasion that it has done this the problem won't go away. I've taken the van back to the garage and he has carried out lots of test and thinks there is something wrong with the engine.below is a list of test that he carried
Compression test:
No 1 cylinder : 65 psi
No 2 cylinder : 140 psi
No 3 cylinder : 65 psi
No 4 cylinder : 140 psi

Cylinder leakage test: all cylinders ok
Valve lift : ok
Tappets : ok
Timing : ok
Fueling : ok

The engine is still under warranty from the engine builder but he won't look at it till I have taken it to a vw specialist garage. Even though I told him all of the above results. He thinks is something to do with the carbs or ignition . I'm at my wits end and don't know what to do next as I don't want to have to pay another garage to do the same test as I've already had done.
I would be very grateful if anyone has any ideas ?
Thanks in advance
Martyn

[81AirCooled]

Those compression readings are odd, maybe the symetry of them will give someone a clue as to what is wrong. It may be meaningless but I don´t know.

I had bad very poor performance after 2 workshops managed to "cock" up my ignition timing. Did you disconnect the idle stabilizer when setting it, and were all vac hoses attached properly?

With the above starting point ignition timing should be set to 4-6° ATDC and advance to around 40° BTDC @ 3000rpm

[mark1967]

Compression test:
No 1 cylinder : 65 psi
No 2 cylinder : 140 psi
No 3 cylinder : 65 psi
No 4 cylinder : 140 psi

Something definately amiss there shouldnt be that much of a difference between cylinders I think 10% variation is about the rule.

The engine is still under warranty from the engine builder but he won't look at it till I have taken it to a vw specialist garage. Even though I told him all of the above results. He thinks is something to do with the carbs or ignition .

I`d love to hear his explanation of mixture or timing affecting the compression readings

[jason k]

something very wrong there.
has anyone been at the hydraulic tappets (adjusting?)
who rebuilt it?

[Martynpfield]

the guy at the garage checked them and said that they were ok. other than that the last person to do any thing with them was the engine shop .He is the person saying that it needs to be looked at by a vw specialist mechanic and also the person that said it was something to do the carbs or the ignition timing as if it was a mechanic fault it wouldn`t come and go?

[Martynpfield]

I fogot to add it was the engine shop in eirth that rebuilt it.

[sarran1955]

Hello,

Check that the cylinder heads are on tight,

You know torque wrench and sfuff

Don't panic, its only a Volksy, loads of poetry, very little magic.

Cordialement,

[Hacksawbob]

are they still hydraulic lifters? some recon jobs replace with solid lifters, so back to gap adjustments.

[Martynpfield]

I've checked it's still got the hydraulic tappets. Is there any other tests or check that could be carried to find out what the problem is?

[Gunslinger]

With those compression figures it has to be an engine fault. It cant be anything to do with carbs or timing etc.
Good luck with TES, I have personal experience and it wasnt pleasant!

[Martynpfield]

I've alredy been back there 3 times with an oil leak And it still not fixed. the last time he said he fixed it took it on a drive and it wasn't leaking . I drove a mile down the road and guess what .... Still leaking oil! Did you get your problem sorted with them?. The mechanic that looked at it and did all of the test rang him on my behalf and he still said it was a fault with the carbs or timing, he had to hang the phone up on the end because he wouldn't listen to him. I called him back and he had the cheek to say does he know what he is doing and that I need to take it to a vw specialist for them to look at it. Costing me more money and to probably get the same result!

[cygnak]

Did he replace the push rod tube seals to try and fix your oil leak. If so i would start by taking a good look at your heads and check the hydraulic tappets are set correctly.

[..lee..]

mechanic is missing something????

its down on compression fact.

yet there is no leak off?

there is ample valve lift
timing and fuelling is ok?

if its down on compression how can he state fuelling is fine? hc shold be through the roof.

you say that it has only happened since the carbs were done which suggests it`s intermittant. if it wasn`t for this i`d be thinking the builder has used different compression pistons but it would never been right then?

[arch]

Those figure's seem to be strange..

I would get them checked again.!!!!

Were they webbers you had fitted.????









I love my van oh and the wife.

[Martynpfield]

The carbs are The standard solex ones, I've had the van looked at by another garage( vw specialist) and it turns out that 3 of the tappets are knackered, the mechanic has said that they look like old ones, so I called the engine shop and he has told me that they are new! And that some one must have adjusted they incorrectly. The problem is he was the last person to check them! We at least I know what wrong now and hopefully it will be ready for my holiday at the start of June
Thanks for the help everyone, greatly appreciated. Keep up the good work.

Martyn