An Engine Rebuild Thread for Beginners

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An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 19:45

So, here begins my Engine Rebuild thread. I am going to attempt to record each stage of the process as I complete it and explain what I’ve done in as simple terms as possible.
Why? Because I don’t really have a clue what I’m doing! I have read most of the rebuild threads on here and, to be honest, I find it all a bit overwhelming and I get lost in the jargon or technical data.

So, I intend to use no jargon (or if I do, explain it in really simple terms). There will be lots of photos. I will shamelessly plagiarise, borrow and blatantly steal bits from other threads - I hope no one is offended.

I intend to list parts used, tools needed and time spent on each stage - I won’t be breaking any records as I have a full time job, two kids and we’ve just sold our house......and, as I may have already mentioned, I haven’t a clue what I’m doing.

I hope that by reading and learning from my inevitable mistakes then some others may realise that they are far more competent and will have a go themselves.

Wish me luck......


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Re: An Engine Rebuild Thread for Beginners

Postby kevtherev » 09 Jul 2019, 19:57

:ok
Last edited by kevtherev on 09 Jul 2019, 20:01, edited 2 times in total.
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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 19:59

History: Bleeding or Gasket problems?
https://r.tapatalk.com/shareLink?share_ ... are_type=t

The above thread explains why I need to do this. It has been pointed out that one of the Compression Seals has failed and therefore the Engine puts combustion gases into the coolant. I don’t know where the compression seals are yet, but I don’t have to yet - hopefully all will become clear as the process evolves.

Removing the Engine was relatively straightforward (as I’d only fitted it 3 months earlier). I followed the Engine removal checklist from this forum (link to follow in next post) but, basically, took loads of photos and disconnected everything that looked like it was attached. I am lucky that I have access to an engine hoist so was able to do this by myself.
There are plenty of threads that cover Engine removal so I won’t expand on it - needless to say, it was a damn sight easier second time round as I’d replaced every rusted nut and bolt.
The Haynes manual also covers Engine removal (Chapter 2 Part B).

I think it took me 4 hours to remove the engine - significantly less than the first time but, as mentioned, I didn’t have rust to contend withImageImageImage


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Re: An Engine Rebuild Thread for Beginners

Postby 937carrera » 09 Jul 2019, 20:01

So your visit to itchyfeet last week resulted in a need for an engine rebuild and the related thread. It must be months since he had a rebuild thread to get stuck into.

You'll learn a lot and get some good advice along the way...., enjoy :D
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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 20:03

Engine removal: 1.9 water-cooled engine removal hints
https://r.tapatalk.com/shareLink?share_ ... are_type=t

Post 20 of the above thread was the checklist I used.


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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 20:24

Having read the various rebuild threads then it became clear that the first hurdle was to ‘remove the heads’........I quickly ran off to learn what the ‘heads’ were.

From the ever trustworthy Wikipedia: (NOT the 8090 Wiki)

In an internal combustion engine, the cylinder head (often informally abbreviated to just head) sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket.

Whereas this was enough to let me locate the heads it isn’t actually correct for a Waterboxer (WBX) Engine. I now know that these engines have two heads, one each side, and unlike standard engines the cylinders in WBX engine don’t stand vertically - they are horizontal, therefore ‘Flat’ and there’s 4 of them.......a Flat 4 engine.

The 2.1 DJ engine I am going to rebuild has two heads and four cylinders.......but no Head Gasket - there will be much discussion of this later! People often refer to a ‘blown head gasket’ and, in fact, that’s what the recovery guy diagnosed on mine - being an old VW it isn’t that straightforward but, hopefully, all will become clear as the strip down progresses.

There are endless threads on here and every other T25 forum regarding the perils of removing the heads from a WBX engine. This is due to the fact that the head studs, or bolts, run from the engine case through the water jacket (the thing that removes the heat from the cylinders when they are pumping) - water and metal aren’t particularly happy bedfellows, so, if the correct coolant/water mix hasn’t been used for the last 10,20,30 years then the head studs will be rusty and weak. Therefore, if you try to twist the rusted nuts off the studs they can snap......this leads to grown men crying and, can actually write off your engine, but Don’t let this put you off......

If the engine isn’t functioning properly due to one of the umpteen seals having failed then you have to remove the heads. If this snaps a stud then you are in no worse a situation - you still have an engine that doesn’t function.
There are methods and techniques for removing broken head studs. Hopefully I won’t need to read them.....


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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 20:36

Prior to removing the engine from the van it was recommended that I check the oil pressure - this was to give an indication of the health of the ‘bottom end’ of the engine. My limited knowledge is that the ‘bottom end’ is where the cam shaft sits and where all the bearings are....... it’s oily down there. To access this mythical bottom end you need to split the engine case, so I checked the oil pressure to hopefully tell me that this wouldn’t be necessary.

Haynes states that VW Specifications for oil pressure are 2bar pressure (or greater) at 80 degrees C at 2000rpm.

When I measured mine, using a oil pressure gauge connected where the oil pressure switch sits between the pushrods on the left hand head, I got 2.8 bar at the above parameters. This was enough to convince me that, hopefully, I just need a ‘top end’ rebuild. This will involve replacing the various seals and gaskets that keep the oil and water cooling systems separate.

So, onto stage one of a 2.1l DJ WBX engine......Removing the Heads


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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 09 Jul 2019, 21:27

Section 1: Removal of the Heads

Tools Needed: Socket Set, 13mm and 17mm socket, Half Inch Ratchet Drive, Large flat blade screwdriver, Propane Gas Torch, Steel ruler, Lump Hammer, Wood block, Scaffold Board, Rags

Stuff clean rags into every orifice - it will stop any contamination getting where it shouldn’t, be that flying nuts, stones or an inquisitive bee.

Time Taken: 3 hours

Engine out of the wife’s estate car and onto a stable work surface
Image

Remove the Rocker covers by using a large screwdriver as a lever in the centre of the spring clip and pushing down
Image

13mm socket to unscrew 2 nuts that secure the rocker arms to the case
ImageImage

On inspection, both rocker arms had adjusting screws that were badly domed, or basically, knackered
Image

These will be added to the shopping list when it comes to putting it back together. Also took the chance to vaguely check the rocker arms - all spring washers were present but I’ll have a better look when I clean everything up.Image

When the rocker arms are removed then you can see the ends of the pushrods and these can be easily withdrawn.
Image

It’s important to keep them in the same order they came out ie: left or right hand head and numbered 1-4 for each side.
I used a cardboard box, with the heads drawn on and slots cut so that the pushrods could be stored in the correct positions. They are oily so be prepared for leakage. Box just visible in picture below
.Image

So, onto the actual Head Studs - there are 8 nuts on each side. They are large, domed nuts of 17mm. 4 sit along the top and 4 behind the rocker cover.
Haynes Chapter 2B Section 16 has a diagram that details the order in which the head nuts are TIGHTENED - I looked at the diagram and immediately started at No 1 when what I actually wanted to do was start at No8 and work backwards.

Number 8 is bottom right, behind the rocker cover. I intentionally used a half inch ratchet drive with an extension bar and a 17mm socket - the thought being that I’m not a big bloke and I wouldn’t be able to do much damage with thisImage

I tried this first one without applying any heat - I wanted to get a ‘feel’ for tightness etc. It immediately turned a quarter of a turn then gave a sharp ‘ting’ noise........I almost cried.
I was absolutely convinced that I’d broken the stud and I’d only be going about 10 minutes.

I was then informed that this noise was actually a positive sign.......it still made me feel sick.
I have a video that records the sound really well......if I can work out how to upload it I will. This was, honestly, the scariest bit of this whole mornings work.

Back to the task, after the stud ‘tinged’ then the nuts immediately tightened again so I got into a rhythm of loosening quarter of a turn, tightening, loosening, hopefully a ‘ting’, tighten, loosen, ‘ting’ tighten etc etc.

At no point did I try to force anything - if I felt it stiffen then I’d just tighten it back up and try again.

I removed the first one, without using heat, but it took 15 mins.

Number 7 (or 2 if you will) is top left, one that is open to corrosion from the engine bay. I gave it an initial try and it wasn’t shifting so broke out the propane torch to apply some direct heat
Image

Heat applied for approximately 2 minutes to try and break the corrosion then tried the socket
Image

The heat helped and I used the same loosen, tighten, ting, tighten, loosen procedure. Each time I was doing no more than a quarter of a turn and as soon as I started to feel and resistance or ‘springiness’ when loosening I immediately stopped and went back the other way.
Image

For each stud it appeared that 3 loud ‘tings’ was the optimum amount - once the stud had released tension 3 times then the nuts would loosen and come off.
Image



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An Engine Rebuild Thread for Beginners

Postby Snowmark » 10 Jul 2019, 08:47

Here’s a link to the video I took of the sounds made by the studs as they release - it was truly a horrific experience the first few times it happened, but as the process went on I learnt to love it as it was a clear indication that the nut would come off cleanly.


https://vimeo.com/347251380


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Re: An Engine Rebuild Thread for Beginners

Postby King Kenny » 10 Jul 2019, 13:32

Good work, young man. Keep going. :ok
I don't know where I am, but I'm having a lovely time!

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Re: An Engine Rebuild Thread for Beginners

Postby kevtherev » 10 Jul 2019, 16:52

When you checked the oil pressure.
What was the engine temperature and oil grade?
Was the value you got a mechanical or electrically derived figure?
Also was a compression check done?
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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 10 Jul 2019, 19:02

kevtherev wrote:When you checked the oil pressure.
What was the engine temperature and oil grade?
Was the value you got a mechanical or electrically derived figure?
Also was a compression check done?


Oil pressure was checked using a wet gauge and values recorded at every temp point 50,60,70 etc up to running temp with cooling fan on.
I did this more out of interest as all I was comparing to was the VW Spec of 2 Bar or above at 80 degrees and 2000rpm.
Have always used 15W40 Mineral, both in this and the old DG.
Compression test has been done when I fitted the engine.....can’t lay my hands on the figures just at the moment but they were healthy enough.


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Re: An Engine Rebuild Thread for Beginners

Postby 937carrera » 10 Jul 2019, 19:52

How far are you planning to go then ?

Good oil pressure means you don't have to split the case, good compression means you don't need to pull the barrels off the pistons, (unless something is amiss when you get the heads off) , so this could be as simple as heads off, inspect & repair where necessary then reassemble.
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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 10 Jul 2019, 20:08

Section 1: Removal of the Heads (Continued)

The removal of the nuts continued without incident - I used heat for the top row and just the socket for the ones that live behind the rocker cover. The process speeded up but every new nut brought another wave of nausea as you constantly think ‘will this be the one that snaps??’

I had removed 6 of the 8 from the left hand head and was left with one behind the rocker cover and one above it. Just trying the socket would not shift these so had to use heat.
Due to the proximity of the springs (valve springs......not sure yet) I had read that you can alter their properties if they are heated too much. Therefore I used a heat shield (Patent Pending) made from a tube of stainless steel to cover the spring and stop them absorbing heat from the propane torch.
Image

This nut took more heating than had previously been required - my theory being that as you remove nuts then the remaining ones are placed under further tension.......or it could have been that my arms were getting tired.
This nut finally gave up the struggle and came off cleanly so I was left with one of the central ones on the top row. I went straight at it with heat, lots and lots of heat.......and it wouldn’t turn a mm.

Had a brew......and heated it again, a lot.......and it didn’t budge but did start to spring back against tension.......I got extremely scared.

I have read lots of accounts of people removing heads and all goes well until the last nut so I did the cowardly thing and had more coffee. I had a complete arsenal of breaker bars of increasing lengths at my disposal but I was just too chicken to try them.

So, I spun the engine round and started on the other side whilst awaiting divine (or otherwise) intervention.
The right hand head (labelled from the rear looking forward, I believe) went unbelievably smoothly, and in about a quarter of the time.

As my confidence had grown with each nut I had begun to get a ‘feel’ for when to stop and tighten back up or when to apply just that extra bit of pressure to release the tension, make the stud ‘ting’ and be closer to removing the nut.

I was a lot more liberal with heat application on the right hand head - I heated each of the nuts in turn. Top ones for 2 mins, lower ones for about a minute.
Within half an hour all 8 nuts were off
Image

So, there are no mechanical fixings holding this head on, just years of corrosion and gunge and old sealant and probably some black magic. In my excitement I grabbed the coolant outlet in an attempt to wiggle the head off......and burnt my hand.
Armed myself with a couple of rags and gave the head a push and a pull
Image
A small crevice appeared between the head and the block and the remaining coolant poured onto my feet.
Image

There was just enough of a gap to see that as the head inches forward that it was dragging the cylinder liners with it - they are easy to see as they are large diameter metal cylinders that seat themselves into a recess in the head, 2 each side.
Image

Image

You don’t want the cylinders to come out when you remove the head as this will leave the pistons on that side of the engine without any support and they will clang down onto the studs, possibly damaging the piston (which are expensive) or snapping a stud.......which would just be extremely unfortunate.
So, a little care required - the cylinder liners have small tabs on each side just behind where they sit in the head. I used a wide bladed screwdriver to lever the cylinder back into the engine and out of the head recess. I put a steel ruler flat against the head face to avoid any damage to the lip as I levered against it.
Image

If needed, you could cut the thick black water jacket seal that runs round the perimeter of the head to give yourself more access to the tabs on the cylinder. I didn’t have to as I have sufficient clearance to get the screwdriver in.

Image

A bit more wiggling required to get the head over the threaded parts of the studs
Image

Next thing you know, the head is off!

Once it is out of the way you have clear access to the pushrod tubes - the 4 silver cylinders at the base of the engine. These can just be pulled away. I took this opportunity to clean the oil and grime from underneath the head of each tube then stuffed a rag into the hole.
Image

Each pushrod tube has two seals, one at the head, one at the base, both are cream in colour. I removed them all as I took out the pushrod tubes and discarded them as I shall be fitting new ones once we rebuild the engine.

So, the right hand head is off and I’m left with just a single nut holding the left hand head on.......time for a brew.
My hope was that by ignoring the situation for a while then the previously heated nut would have cooled, contracted and hopefully broken the corrosion that was stopping it moving. Spun the engine back round and tried the last remaining nut cold......it turned.....a tiny amount. I sweated.......a huge amount.
Tightened, loosened, tightened, loosened, felt sick etc.....then it finally gave up and off it came.

More wiggling produced nothing- this head didn’t want to move so it was given a little lateral persuasion with a big hammer, a block of wood and some nervous taps from a below average sized man
Image

This gave just enough of a gap to use the screwdriver levering technique and the head came off leaving the cylinders behind.
Image

As the head came off then it dislodged the cylinders from the recess that they sit in at the engine block end - therefore they were loose and prone to drop out. They could be easily pushed home
Image




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Re: An Engine Rebuild Thread for Beginners

Postby Snowmark » 10 Jul 2019, 20:19

937carrera wrote:How far are you planning to go then ?

Good oil pressure means you don't have to split the case, good compression means you don't need to pull the barrels off the pistons, (unless something is amiss when you get the heads off) , so this could be as simple as heads off, inspect & repair where necessary then reassemble.


Honest answer is ‘don’t know yet’ - I’m hoping not to split the case as the oil pressure was good, but, I haven’t looked at the cam shaft yet (or know what I’m looking for) so will reserve judgement.

I would like to end up in a situation where I refit an engine into the van that I have confidence in.......therefore, couple this desire with my mild OCD and I suspect that I’ll replace all seals, gaskets and probably piston rings whilst I’m there. It just seems like, once you’ve gone to the trouble of removing the heads then you might as well - happy for advice on this.
As yet, not really had a chance to check the liners for condition so I guess things will become clearer as things become cleaner....


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