Simple Turbocharged Zetec: Build Diary

[Ahmotorsport]

Also, as an add on you can buy Wossner Zetec Turbo pistons now.

 

You've been able to buy Wossner pistons for the Zetec for several years, I used to be a reseller but the distributor was pretty useless so I dropped them. They used to do them for the 1.8 too, which is a preferable engine to turbocharge.

Well I was a bit young then so that's why I said now as I wasn't sure. Make some nice pistons though.

[Stu]

Cheap and cheerful is how I would describe them.

[Ahmotorsport]

Cheap and cheerful is how I would describe them.

When we last used em, not too long ago they were good, weights were pretty close between them and had no problems.

[Stu]

Okay, so let's continue.

 

Block and crank back from the machine shop.

 

 

Machining taken place: cylinder bore + hone, deck facing and mains line hone.

 

I always line hone every engine. On old blocks like this it's a good idea because the block material has settled down now and it's unlikely the mains are completely true. Using high mileage blocks is always preferable on this kind of engine because brand new blocks have more potential of failure due to block flex. I'm not a metallurgist so I won't try to go into the detail. For example BMW used old road car blocks for their turbocharged F1 engines in the 80's. They were much stronger than brand new blocks!

 

On a turbocharged engine, you want to take as little off the top deck as possible. You would normally ask your machine to "skim to clean", which basically means take off the smallest amount of material to create a flat deck. It's very important to have a perfectly flat deck when you intend to use metal head gaskets (like I will here). Same applies to the cylinder head. I think on this engine it only took a couple of thou to clean the deck up which would make a negligible difference to the final compression ratio.

 

The machine shop cleaned the block in their caustic tank, however this is nowhere near clean enough for a build so on with the cleaning process!

 

 

 

Here's a better photo of the block. You can see that the caustic cleaning process has taken a lot of the crap from the exterior of the block which makes life easier when painting the block!

 

 

Okay so time for the block to go into the degreasing tank:

 

 

Let me set an expectation here. You will need to spend at least an hour cleaning the block. Preferably two hours. Before this block ended up in the degreasing tank I steam-cleaned it outside for a good 20 minutes. You need to get in every nook and cranny, especially the oil galleries. At the back of the block there is a threaded bung at the end of the main oil gallery - you need to carefully remove this before you start cleaning the block or you'll just end up pushing all the crap to the end of the gallery and risk engine failure in the future. I've seen this happen with Ze-VH conversions where people bung up some of the oil galleries near the block deck and forget to remove them when cleaning/prepping the block. Easy mistake to make, but can be fatal!

 

The block cleaning is a three stage process. The first stage is the steam clean/jetwash, the second stage is the degreasing tank which should get rid of any large pieces of swarf from the machining process, and the final stage is with the block in a clean area on the engine stand where you will go through everything with pipe cleaners, brake cleaner and an air line.

 

So back to the degreasing tank photo. The important places to clean are all of the oil galleries. You can see the holes around the main bearings, clean these excessively. Clean the main oil gallery excessively. Use purpose-made pipe cleaners. In, out, in, out, shake it all about. You really cannot spend too long doing this. I wear gloves when handling degreasing fluids as it plays hell with my beautiful soft hands.

 

 

 

A view from the deck side of the block. You can see it's coming together a bit now on the clean front. Some of this though is just because the entire block is now wet with fluid. The large holes on the deck face next to the main head bolt holes are the oil drains back into the sump. Clean these thoroughly too. You can get pipe cleaners of most sizes to fit the various holes on the engine. You can't get all the way in a few of them (particularly the oil galleries on the mains) - you rely on air power to clean these out later. Another quick tip is to remove the under-piston oil squirt jets before you start this work as they can trap swarf in them. You will clean out the spray jets themselves in stage 3 of the cleaning process.

 

 

Perfect bores..

 

 

 

 

Here's a better view of the mains and galleries.. you can see the cross-hatching on the mains from the line hone process.. Be careful, things will be very sharp on the edges where machining has taken place! It doesn't hurt to deburr the edges of the mains and main caps before you start the cleaning process.. You can easily cut yourself on them.. You can also see the under-piston oil spray jets removed for the cleaning process..

 

 

 

Here's the main caps and bolts..

 

 

These will need thoroughly cleaning by the same process too. Keep them all together, you don't need to replace the bolts. I tend to leave them wrapped in a clean rag once they've been cleaned. You can also see in the bottom-left of this photo the two dowels that were removed from the block deck by the machine shop.

 

 

Whilst this was going on, the cylinder head was being rebuilt. Unfortunately I was being cheap at the time and instead of using our usual head guy (who used to do some WRC heads) I used specialised engines. There were a couple of issues with the head rebuild, one annoying item was the fact they painted the head with silver paint. Another issue was they left it sitting in their acid tank longer than I think was a good idea. This may have caused a problem which I will document later in this thread. This isn't a bad review of Specialised Engines, the painting isn't the end of the world and it may have just been luck on the acid tank problem.

 

 

 

For some reason they didn't remove the exhaust studs either. Probably didn't want the hassle in case one snapped in situ (possible). Again, these are things you want to get penetrating oil (plus-gas) on ASAP and keep soaking them for a week in advance. These can be a real pain in the arse to remove cleanly. Make sure you have a stud extractor to hand just in case!

 

 

The machine shop also ground the crank whilst it was there. I've yet come across a zetec crank that didn't require a grind. There's a lot of myth on the internet about grinding cranks and how it's a bad idea on some engines. I've never really any conclusive data that backs this up. The Subaru fraternity strongly recommend against grinding EJ20 cranks because it's impossible to remove all of the swarf apparently and will lead to engine failures. My view is the galleries have an in and an out which means you must be able to clean it out, one way or another.

 

 

The yellow stuff is an anti-corrosive grease to stop the journals from rusting after the maching process.

 

Grinding the crank is where the journals (which touch the bearing faces in the block) are machined down to either make them round again, or to remove imperfections or damage. When you grind a crank you then have to use over-sized bearings to make up the difference for the material you have removed.

 

This particular machine shop seems to have a lazy tosspot on the crank grinding machine. He rarely uses the additional strap to hold the crank down and you often end up with oval shaped journals. It's important to measure the journals in a few different places just to make sure it's consistent (i'd expect a crank journal to be round to at least quarter of a thou).

 

This does bring me onto measuring stuff. Never assume that a 3rd party, like a machine shop, has done their job properly. More often than not they cock up. My particular place seem to have a brain fart every now and again and make really stupid mistakes, even on basic jobs like honing cylinders to the right size. Ahmed has literally had to go down there and show them how to use their tools before.

 

 

The crank must be cleaned in the degreasing tank. In some ways spend more time on the crank than the block (relatively). It's worth spending the time trying to find suitable pipe cleaners etc. to get right into the crank journals. The crank is the lifeline of the engine. It's crucial that there are no blockages or swarf or you'll quickly end up over-heating bearings in the engine which will most likely result in at best a spun bearing, or at worst a complete engine failure. Just for reference, an engine failure will often destroy the turbo too, which add another few hundred quid onto the future repair cost. You can somewhat mitigate this effect by running an in line oil filter to the turbo but that's not really a fix for bad preparation!

 

Finishing up with a photo of the cleaned head and crank shaft..

 

 

 

Feel free to ask any questions.. I've not built an engine for ages so there may be some small details i'm forgetting to cover! Sorry I don't have many photos of the actual processes i'm loosely trying to describe, but the pics were never designed to be a tutorial, just a photo archive really!

 

 

Until next time..

[sidrick]

Nice info.

[waynegc123]

This is really really interesting!

[Stu]

Thanks guys, plenty more to come.

 

Here are a few book I recommend if you want to go down the route of building engines or doing turbo conversions..

 

First up is a great general purpose book on engine building.. it's American and has a heavy V8 focus, but there is a lot of great advice in there (such as measure, measure and then measure again!)..

 

http://ecx.images-amazon.com/images/I/51EFG-71cYL._BO2,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA300_SH20_OU02_.jpg

 

 

Next up is a good book on turbo conversions.. it covers a lot of the theory and physics.. I don't agree with everything in the book, but it's a worthwhile read if you want to understand the concepts..

 

http://ecx.images-amazon.com/images/I/51WDFpv9S9L._BO2,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA300_SH20_OU02_.jpg

 

 

And for the hardcore out there.. this is the BIBLE of automotive topics.. it doesn't go into great detail on a lot of stuff, but it has ALL of the automotive formulae you'll ever need.. this is the book of facts, not opinions or trial and error.. 8th edition is the latest AFAIK

 

http://ecx.images-amazon.com/images/I/41UPkNQYL6L._BO2,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA300_SH20_OU02_.jpg

 

 

Enjoy

Edited September 18, 2012 by Stu

[bongo]

really enjoying this and hope to have funds in the future to do this.

 

(bookmarked this topic link )

[Naylor2006]

Me too, engine builds are my favourite, there is so many different parts all so important to provide one end result, I find it fascinating.

 

Not sure this would give me the confidence to do it myself though, I'd pay Stu to build it still, if he did still build that is.

[Ahmotorsport]

Couldn't agree more with 'Maximum Boost' i read it and some of the stuff was like 'forum bullshite' but when it actually got down to the job in hand i thought it was very informative.

[JC]

very interesting reading and thanks for the links

 

also are you going to put suggested / estimated prices on the steps in the process?

[Jordan99940]

very interesting reading and thanks for the links

 

also are you going to put suggested / estimated prices on the steps in the process?

 

Wouldn't the prices from 10 years ago slightly differ from today's prices?

[Stu]

Wouldn't the prices from 10 years ago slightly differ from today's prices?

 

I wouldn't say they've changed that much. This engine was built in 2005, not 2002, not that it'd make much difference.

 

I would go back and add in some prices but I cannae edit my posts!

 

 

Let me try and re-cap on some..

 

Pistons - £600

Rods - £700 (3 month wait)

 

Machining:

Bore/Hone, Deck, Line-Hone & Clean - £300 or so

Crank Grind - £90 (at a guess)

 

I'll try and remember to add them as I go along.. but remind me if I miss anything!

[Stu]

Okay, let's proceed..

 

 

So got the block clean, cylinder is built up, ready to do a dummy build. The main reason for doing a dummy build at this time is to measure the static compression ratio of the engine. You can do this in three main ways :-

 

1) Using just calculations and hope for the best (inaccurate)

2) Measuring the combustion chamber volumes of the block, head and gasket(s) separately (not too bad)

3) Building the engine up with a single piston in place to measure the actual volume (best)

 

Of course I chose #3..

 

 

So this means you have to put a single piston and rod (+ crank) into the engine, get the piston at top dead centre (TDC), seal the piston in the bore (vaseline), hand-screw the head onto the block (doesnt require full torque). Then you can fill the combustion chamber with a liquid (e.g. paraffin) and using a burette you can measure exactly how many CC's the combustion chamber holds. Then with calculations which incorporate the cylinder bore and stroke, you can work out the compression ratio.. The target CR for this engine was around 7.5:1..

 

So pictures.. nothing too detailed i'm afraid.. but i'll try and describe it..

 

 

So this is the cylinder block after cleaning.. you'll notice how quickly you get a surface rust once you let it open to the atmosphere.. not much you can do about this really other than spray it with a light oil.. I don't tend to worry too much...

 

 

 

So here's the crank bolted into the engine.. obviously with some bearings/shells.. You dont have to use your new shiny crank and bearings, you can use an old crank with suitable shells for the dummy build.. just make sure it's all clean.

 

 

Crank will be hand tight.. no need to torque right up.. not that it'd be a problem

 

 

At this time it's a good idea to have a clean bench laid out with your rotating components.. pistons, rods, rings, etc.. you'll notice the note book.. also a good idea.. currently written down on the note book are the weights of each piston and rod package.. I don't usually bother balancing the rods end to end, but I do like each piston and rod to be very close to eachother.. you need to weigh each piston and rod individually and figure out which is the best compromise.. IIRC I did take off a little material from the rods to get them all down to within a gram of eachother.. worth doing, just don't take material off the wrong place!

 

 

So here on the bench there are pistons, rods, rings, bearings, torque wrench, ring tool, head gasket...

 

 

Here's the piston used to do the dummy build.. it doesn't need any rings fitting to it for this stage which means it just plops straight down into the cylinder without too much grief.. Of course it is attached to the rod.. TIP: be careful when dropping a piston and rod down the cylinder when there is a crank shaft bolted into place.. the sharp edges of the rod can very easily damage the journals on the crank and you'll be left with some repair work to do or risk bearing score and/or engine failure..

 

 

Piston is at TDC (as set with a dial/dti gauge).. and a decent portion of vaseline is pushed down around the sides of the piston.. before the next stage the excess has to be cleared away so that only the gap around the piston has vaseline present.. you don't want any on the piston crown, or in the valve cut-outs, basically no grease above the piston at all!

 

 

Next step is to place the cylinder head carefully on the block (with head gasket).. you'll notice on the previous photo the head locating dowels have been placed back into the block deck..

 

 

 

You can get away with only bolting the head around the cylinder you are measuring.. four bolts in the case of a zetec..

 

 

Unfortunately I don't have any photos of the burette in action.. but i'm sure you can imagine a large syringe full of white spirit filling up the combustion chamber via the spark plug hole!.. Fill the chamber up until the fluid gets to the bottom of the spark plug hole threads.. this is a good point of reference and is probably about as good as you can measure from peeping down the hole..

 

Here's a couple of links if you'd like to know how to calculate CR, or just use a wizard:

 

http://chainganger.co.uk/Page2/Page2.html

http://www.aircooledtech.com/calculating_cr/

http://www.csgnetwork.com/compcalc.html

 

 

 

Okay, so dummy build done (as far as CR goes).. static CR came out at about 7.6:1 which is fine for the package...

 

Used this state as an opportunity to paint the block.. as follows..

 

 

 

Went for a gloss black finish. Probably not the best idea, satin or smooth black from hammerite is a much better finish in my opinion. Each to their own though.

 

You need to mask off EVERYTHING that you do not want painted. As this engine had no sump installed, the underside of the engine was bagged/sealed off and everywhere else was masked off using simple masking tape. If you have had the top deck machined as part of the build, this makes life fairly easy to mask the complex shapes around the top deck. Rather than dick around with a knife trying to get it perfect around the block deck, you can simply overlap your masking tape over the edge and then use the ball end of a hammer around the edge of the deck to effectively cut the tape in-situ.. you don't have to hit it hard.. it's like scoring the tape..

 

I would recommend masking off any faces on the block where you may be bolting something too.. paint or powder compresses when you fasten something to it and over time can break up and make a part go loose..

 

 

Another view, this one shows the front breather location.. a lot of people block off the front breather.. you kind of have to when you're using an escort rs turbo manifold... as you will see later

 

 

 

And here's the block with the tape removed.. doesn't look too bad, but gloss is cack..

 

 

 

 

 

Until next time..

[Scort_CVH]

Very informative, following closely