Blowing cylinder heads VW Type 4 engine

[mark tucker]

if the cylinders had stoped firing/running they will pull oil up so...it may or may not have bad rings. were they properly torqued?were they still torqued when pulled down? never use sily cone for the head gadget. check everything!!

[Clatter]

I’d pull that clear apart and go through it.

Unless you know what’s in there, you don’t.

Check for a spread center main first.
_________________
Bus Motor Build

What’s That Noise?!?

[raygreenwood]

[PaoloT2]

Hello All,

Thanks for all the replies. I will try answer all the questions.
I have taken more pictures tonight but I haven't got much time due to work until the weekend...Anyway.

1. It is a 1800cc and NOT 1700cc. I have based my first post on the documentation I had with the van but in reality when measuring the bore it is 93mm (see picture) so if I am correct this equals to a 1800cc -> right heads are on it then. Apologies for the confusion.

2. There was "fresh oil" when I opened but I am wondering if it doesn't come from the fact that the engine was moved a lot when removing it and lifting it up on my bench ? I did not drive with the van so not sure if it was burning oil.

3. Yes it is black RTV silicone on the sealing surface ! Not sure why this was put there...I have started to scrape it off slightly to see underneath if there was any damage. (see picture)

4. Yes there is flaky deposit on the valve.

5. I have checked the cylinders studs and they are tight.

6. I will check the piston rings. The previous owner told me they have been replaced but looking at this they might not have been or not been fitted properly...

7. Yes everything was torqued as per manual on the head.


As I said, I will check the piston rings and cylinders in detail and post more pictures but clearly what has been done is really bad...Some cylinders are damaged on the outside wings.


Thanks. Cheers

[raygreenwood]

Wow!

Oily!

So yes.....its a 1.8L. Was there silicone RTV under and on the sealing rings or just around the outside of the cylinder bore?

One can only assume or speculate that someone assembled this engine...had "0" oil control and lots of oil seepage...and then took heads off and gooped it up thinking that would stop the leaking.

It would be interesting to see the cylinder bores and rings. Yep..tear it down completely. Ray

[PaoloT2]

There was RTV only on the outside of the cylinder bore.
Inside just those shims.
Yes, I am wondering if its worth buying a new kit. I have found a kit piston & barrels for £300 on Heritage...

Thanks.

[raygreenwood]

[Wreck]

Before you remove the cylinders put a straight edge across them .verify if you have an issue with the flatness of the case/cylinders or if the heads were just loose because of the silicon .

[PaoloT2]

[PaoloT2]

[FreeBug]

Type 4 gasket kits come with two sets of shimming rings. That service bulletin prescribed putting the larger shims under the barrel, and forgo the "head gasket" shims. It also talks of cutting notches in the rods for better oiling...but that's another story (not worth exploring in this case). I'm a convinced head-lapper, too.

The brown valve is a good color, but it's the only "dry" one. There are serious oil issues. If you can only change 1 part, I'd change the exhaust valves. The heads probably want a going-over. The easiest thing to check is probably valve guide wear. If it's wrong, there's no avoiding rebuilding the heads.

What was the blowback like through the breather?

Are there any fuel issues which could be affecting sealing?

I have to agree with the cam, sorta type4 Achille's heal, it's probably out of spec. You can see a lot of cam stuff through the holes, without opening the case. Start there.

[Vanapplebomb]

[quote="FreeBug"]Type 4 gasket kits come with two sets of shimming rings. That service bulletin prescribed putting the larger shims under the barrel, and forgo the "head gasket" shims. It also talks of cutting notches in the rods for better oiling...but that's another story (not worth exploring in this case). I'm a convinced head-lapper[quote=“FreeBug”]

It does specify the thick spacer, but I wouldn’t put the recommended barrel spacer in. You want that deck tighter. With that thick spacer they want you to add, your squish/quench SUCKS, and it is a less the ideal burn, and the engine runs hotter. Tighten that deck and bump the compression slightly as a result, and it will actually run a bit cooler. Counterintuitive, I know, but data doesn’t lie. That big deck is no good. Shoot for 0.030”… or 0.040” to be safe if you had a worn engine or are not confident in your measuring tools/skills. I would never put a T4 together with more than 0.040” deck.

Notching the rod journals for oiling the pistons is a good, free, and easy mod to do.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Vanapplebomb]

[Clatter]

Tear it clear down if just to get it cleaned up..!
These motors cool all over, not just by the fins.
If it's covered in an insulating blanket of oil sludge it won't live.
Even if the lower end is fine, at least you'll be able to trust it.

FWIW, the link in my sig might be helpful...
_________________
Bus Motor Build

What’s That Noise?!?

[PaoloT2]

Hello All,

I have managed to work a bit more on the engine today.
I have started to clean one of the head and it doesn't look too bad to be honest.
Definitely flat as well as barrels. Good News.

The piston rings are definitely new but it looks like the oil ring was overlapping...
I have taken some pictures for you to see.

Hopefully I can get further tomorrow but I need to buy a proper tool for the valve removal and for the deck measurement.

The shim in the heads are measuring 0,75mm x 2 and the shims under the barrels 0,20mm.
Does it sound correct to you ? Do you know what I would be looking at approx to get the correct deck height ?

I have posted some pictures as well.

Thank you.

[Vanapplebomb]

This image tells me that it was a later case. Notice the notch between the barrels inside the case at center right in the photograph… I would be surprised if it was still flat after 40 years of use. How exactly did you determine flatness/parallelism or the cylinders at the head end when installed in the case?

_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[PaoloT2]

I have followed Wreck advice and used a ruler as shown in his picture to check flatness at the cylinder barrels top when in the case.

What does the notch mean exactly please ?

Thanks.

[Vanapplebomb]

Was it visual, or did you try and slide shim stock or a thin 0.001 - 0.002 feeler gauge between the straight edge and cylinders near where the cylinders are close together?

If it is in fact flat, you probably have a good core engine for a rebuild.

That notch was machined in later cases so that there was more room for air to move back and forth between the 1/3 and the 2/4 cylinders while the engine was running. Why VW thought it was necessary to have more room for windage is a bit of a mystery since early cases do just fine even with big bore 103mm /105mm cylinders. Machining that material away removed a fair amount of meat between the cylinders, and is one big reason why later cases are more likely to sag in the center.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[PaoloT2]

No I haven't tried with a shim. I will try if possible.
Do you agree with the oil rings overlapping ?

Thanks.

[Vanapplebomb]

Best to try with a shim. You may not easily be able to see if there is a gap. I say 0.002” or more of a gap is worthy of decking the case. It’s not easy to see 0.002” just by eye. In my experience, eyeballing it will only tell you if it’s really out of whack or not.

I wouldn’t worry about the way your oil ring pieces are lined up. As long as all three parts are there it will function fine so long as everything is in good shape. Given the wet cylinders, I question that second part. If it’s not a worn valve guide, either the ring lands on the pistons are shot, end gape of the rings is too large (thus low ring tension), or the cylinders are worn…possibly out of round.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021