Introduction: Polishing Cast Engine Parts and Dressing Up a Tatty Old Engine

About: Evil Genius. Diabolical Scary Man. Dark Lord. Lover of Bagpipes and Accordions. Leaver of Lego Brocks on the Carpet in the Dead of Night. Ok, ok. I am really an engineer, I work on ships for a living, usually…

The car has been a labour of love for many years . It's the embodiment of the "Hotwheels toy" I've had in my head some I was a kid, and a test to see what limits my skills and creativity really have .

This instructable is about the engine in my Volksrod. The spec:

Stock 1600 stroke and bore, but with forged pistons and con rods.

Engle TS20 turbo camshaft and straight cut cam gears

John Maher Racing ported and polished heads, stainless valves and double valve springs

Lightened and dynamically balanced bottom end

8 dowel counterweighted crank with forged and balanced lightweight flywheel

009 Bosch distributor with max advance limited to prevent manifold detonations

Dellorto DHLA sidedraft carburettor

Garret T3 turbocharger in drawthrough configuration

This instructable touches on the build up, but mostly on making any engine aesthetically pleasing with little more than elbow grease and standard tools.

Credit to LVH Engines and Restos, without whom many of my Instructables would not be possible!


Mostly, you will need nothing more than:

Various grades of sand paper and wet & dry

Some polishing compound

A good rotary tool (drill, dremmel, air sander, whatever your preferred weapon of choice is)

A large industrial tin of elbow grease

Extra large cup of pateince

A selection of spanners, tools and whatnot appropriate to your engine and the parts you want to clean up

Carefully managed expectations - if you can't do this, then a dustpan and brush for sweeping up those shattered hopes and dreams!

If you are going advanced, then this really depends on what you want to achieve. My Instructable shows what can be done with some vision, basic tools, lots of work and a clear idea of where you want to end up.

Step 1: Step 1 - the Starting Point

This engine was sort of thrown together out of whatever was available at first. The end result was a functional engine that looked a mess. I hated the oil line routes, I hated the oil filter location, I really hated the exhaust, for a custom engine this needed a little work to be made pretty.

The exhaust header was thrown together from mild steel exhaust parts, cut and welded to route to the turbo. So, the first thing to do was to look at possibilities for making a new header.

Mild steel is not a great material for a turbocharged car, the walls were too thin and the steel just not thick enough to tolerate the immense heat generated. At sustained full chat, this car would make the runners glow cherry red.

I set about pulling the existing header off, and mocked up a few ideas on SketchUp.

There's a great deal of misunderstanding about exhaust headers out there. Many folk have the vague notion that all the runners have to be the same length, because this magically "tunes" the engine and makes it "more powerful". This is true, to a point, but the subject is huge, and making all the runners the same length "tunes" to a certain very narrow RPM band with the length of the runner dictating "where" that tuned peak in power is in the rev range. Blindly making them the same length is not some sort of magical recipe for a more powerful engine, there's a good deal more science and physics behind a well designed exhaust header. People also misunderstand what "BHP" is, it is a product of torque and RPM. It's too big of a topic for an Instructable, that's for sure!

Furthermore, just because your power peaks at a higher value, that does not necessarily give you more usable power. It is far better to have a flatter, wider power band for a road car than it is one with a very sharp peak in power high up the rev range. If you imagine the power plotted on a graph, and calculate the area beneath your line, a greater area here is a far higher average power. this is what you should strive for in a road going vehicle. This is why in many standard production cars, the exhaust manifolds tend to have different length runners - note particularly the Subaru flat 4.

Suffice to say, I do not want to tune for a sharp peak in power. nor do I want an exhaust that sounds like a whiny drone. so, I deliberately made my runners vastly different lengths. It also has the advantage of looking a bit bonkers! the header evolved somewhat organically from this point though...

Step 2: Step 2: While It's All in Bits...

At this point, I figured I might as well strip the engine down and take a look inside. Don't take an engine apart without a workshop manual, good tools, and most importantly make sure you have the time to do it, and don't need the car right away if you realise you can't put it back together!

The VW Flat 4 engine is a simple beast, and with a selection of standard tools and a workshop manual, anyone mechanically minded should have no trouble stripping and rebuilding one.

I won't go into rebuilding a VW type 1 engine here, as there's nothing I can add that a good workshop manual can't tell you (Haynes is my personal "Go To"). Suffice to say, all looked well inside the engine, the pistons and barrels were in great condition, the crank bearings were well in spec and the heads looked almost new aside from a little carbon build up.

I gave everything a clean, pressure washed the crank case before putting that through the wash tank and treated it to a jolly good scrubbing. Nothing more than care, attention, and love.

I would not recommend steam cleaning these, as they are magnesium alloy in a VW Beetle (or aluminium if you have an aftermarket case), some kerosene, de-greaser, scotch bright, a tooth brush and some patience are all you really need. Once it had dried off, I gave it another pressure wash to make sure it was clean of any solvents etc, dried it in the sun, and gave the outside of the crank case a liberal coating of black engine enamel paint. Make sure you mask everything off properly, you don't want paint on any mating faces!

I decided to polish the cast aluminium manifolds and turbo compressor housing while I was at it, so dismantled the turbo and set about the parts with an air powered rotary sander.

This is very easy, it just takes time and managed expectations. The castings were rough, with a sand finish from the casting process.

So the first step is to take some 80 grit paper and gently knock this back to shiny metal. I also took all the casting numbers off, as I don't need them and sanding around them is Jedi Level polishing. However, if you leave some detail, you can always paint the recesses to make them really pop!

Once you have an even finish with the 80 grit (and go easy, 80 grit is aggressive), you simply up the grit of paper you use. 120, 240, 500, and so on. I did not want a mirror finish, I like the satin finish, but you can go as nuts as you like until you can see your mad gurning face in mirror-like finish. Once you have the castings smooth enough, you could get a polishing mop in your rotary tool and use any off the shelf polishing kit to get that mirror finish if you like.

Be careful though of what you expect from this. Getting things to a perfect, chrome-like finish is really hard without the correct tooling. You will also have areas that you just can't get to properly, so don't be disheartened when it doesn't look like the whole thing is made of liquid metal.

Once I was happy with the finish, I gave it all a final polish with a polishing mop and standard cutting comound to get rid of most of the abrasion marks, and then a nice coating of wax polish to preserve the finish. Wax polish will also fill the tiny imperfections and make the piece look a little smoother.

Aluminium is somewhat reactive, and you run the risk of it dulling over time as it forms an aluminium oxide layer. Likely you could anodise them, dye them, whatever you like, but for me I like a little genuine patina on metal and it gives me something to polish later on. I was very happy with the results though, a big improvement from the factory finish.

At this stage I also made myself a little stainless oil return for the crank case. This was a piece of stainless pipe, tapped to 1/2" BSP to accept a brass compression fitting later, as I had something special planned for the oil lines... I TIG welded this to a stainless fuel pump blank that I drilled out to match the holes, as my oil return is where the factory push rod driven fuel pump used to be on top of the crank case (I have long since swapped for an electric fuel pump as the stock pump cannot deliver the volume of fuel I need when the engine is at full chat and full boost).

I guess the point I'm driving at here is attention to detail. Simply cleaning, polishing and painting can work wonders on a tired looking engine. The mantra is simple:
If it's mucky, clean it.

If it's stained or rough, polish it.

If it won't polish, paint it.

Use correct paints for the application, make sure it has the temperature resistance for the environment it will be in, and the real trick is that your paint will only look as good as the surface to which it is applied. Your secret weapon is satin, matte, and hammer finish paints. If the surface is rough, your paint will be to. Make it look like it is supposed to be that way!

Step 3: Step 3: Rebuild the Engine

Once I was happy, I started to put the engine back together.

I had purchased myself some new tin wear which was cadmium plated. I was going to paint this, but decided I quite liked the look of the plating.

I also bought some anodised pushrod tubes as they matched the cadmium plated tin wear and are a nice investment. For anyone who knows these engines, they do like to throw oil out at the slightest excuse. The pushrod tubes are a particular problem but these SCAT aluminium ones are re-usable and seem to seal quite nicely.

I'm sure you will agree the engine is already looking far tidier than when she started!

Carefully following the workshop manual I triple checked everything and built the engine slowly, being sure to take plenty of coffee breaks and not jump ahead. It is very easy to get carried away only to have to disassemble several parts because you missed something small but crucial!

Step 4: Step 4: Fabricating the New Header

The new header was manufactured in 316 marine grade stainless steel, 38mm outer pipe diameter, and TIG welded with a gas purge inside the tubes to give a nice, clean weld.

It was made using lots of small bends welded together, and as you can see, things got a bit carried away with the "Make it look bonkers" remit. A stainless "Y" shaped intake runner was made in the same way at the same time.

the careful designs I made in SketchUp went in the bin, and the header was made organically.

There really isn't much to say that the pictures can't communicate. This takes skill, time, and expensive tools. Leave advanced stuff like this to the pros, unless you have the time and resources to really immerse yourself. I was extremely happy with it, the welds are gorgeous and really add a nice aesthetic quality to the overall look. Unfortunately, I have no pictures of the manufacturing process - only of the finished product.

Step 5: Step 5: Rebuilding the Carburettor

The Dellorto carburettor really had seen better days. The carb body was damaged, tired, and really needed vapour blasting. However, I don't have a vapour blaster.

I contacted a couple of spares places, and one told me they had a reconditioned DHLA body on the shelf for sale for the princely sum of £90. I opted to go for it along with a rebuild kit, and was not disappointed when it arrived.

I carefully dismantled my carburettor and transferred all the parts over using the fresh gaskets and parts in the rebuild kit. I also painted a few parts in satin black to give a nice bit of detail. I used an exploded diagram I found online to make sure I put it back together properly. If you do something similar with a carburettor, just take your time, make notes, take pictures and remember where you left stuff. I lost one critical part and it took me over an hour to remember it was in my pocket!!! I would STRONGLY advise laying down a white cloth and working on that, then you can easily find the parts. A cluttered workbench is not a great place to work.

All the brass parts got a jolly good clean on the wire wheel. I did contemplate polishing them but quickly decided against it since they would stay shiny for less time than it took my coffee to cool down in the salty sea air where I live.

I had a Vintage Speed air cleaner, but sadly the one I had was for an Weber IDF carburettor which has a slightly different top place footprint. Not to worry though, where there's a will there's a way!

The mounting holes were closed up with a piece of aluminium machined to size, threaded, and bonded in. The surface was sanded flat, and new holes drilled in the correct place. Studs fitted, and the carb now accepted the base plate. The good thing is that the manifolds are interchangeable between Dellorto and Weber carbs, which means the throttle bodies were in the same place. This in turn means that the holes here at least lined up with teh filter plate.

Air cleaner fitted, and my carburettor was looking factory fresh again!

Step 6: Step 6: Fitting the Carb and "Silencer" and FIRE IT UP!

Once I was happy with the carb, it was time to fit it along with the supertrap silencer I had. I don't think I will keep the supertrap, but it's all I have at the moment and I quite like the upright "Smoke Stack" look.

Once the carb was fitted, it was time to test fire the engine. I stuck the old oil lines back on for now while I made sure the engine fired and could be put back in the car. Timing was set as per manual; rockers adjusted to specification, compression and oil pressure checked, and a final once-over of everything was made before hitting the button.

It is very good practice at this point to remove the spark plugs and spin the engine over to allow the oil pressure to build. removing the spark plugs means that the cylinders aren't sealed and so the starter motor has not got to work against the compression of the engine to generate oil pressure.

Once you have oil pressure (we simply hooked up a test lamp to the oil pressure warning sensor), watch to see how long it takes pressure to die off again. It should hold for a few seconds and not die the second you stop spinning the engine. If you lose pressure immediately, repeat this step until pressure holds. This is to remove any air locks and to get oil around the whole engine. It is also where you will discover problems without costing you a whole engine!

To my amazement, it fired up almost immediately - usually after a fresh build there are teething troubles, things don't want to behave, and you have to do a lot of cranking before you get a successful start. But this engine REALLY wanted to go!

I was delighted with the sound it made! It was also far easier to start with the new intake, as it matched up far better and flowed far more freely.

Step 7: Step 7: Plumbing

After deciding I didn't like any of the traditional oil lines on offer, and wanting to avoid the braided steel with anodised aluminium option since everyone with Ebay and a spanner seems to use them now, I once again decided to go "Old Skool".

Out with the standard plumbing tools, and fitting compression joints to all the oilways on the crank case. Happily, BSP and NTP threads are close enough to what was on there in most cases, and where there wasn't a match, I was able to machine something up on the lathe.

I had to remove the fanshroud to get in there with the tools.

I sealed each coupling up with a little locktight 574 engine sealer, and measured and bent copper to fit. The tool I used left too many marks on the copper for my liking, but I will have another go with a different bender at some point. The larger 15mm diameters needed annealed copper which is quite pricey, but the 10mm and 12mm lines were just fine to bend without the walls collapsing.

I was very happy with the results, and so reattached the fan shroud and moved on to the ignition leads...

It is worth noting that a this was done with standard tools available in any hardwear shop.

Step 8: Step 8: Keeping the Spark!

After looking at the various options out there for HT leads and finding I didn't like any of them all that much, I decided to make some and draw inspiration from old motorcycles.

I got hold of some cloth braided cable, terminals, screw caps and some brass round bar.

The brass bar was to extend the spark plugs, since they are buried in the heads and access is really tight. But by boring both ends and tapping them and putting a knurl on one end (for grip!), I could remove the push fit screw caps from the spark plugs to leave the threads exposed, and screw on the brass bar.

Then in the outboard side, I wound in some grub screws to put the flag terminals onto and secured them with knurled brass nuts.very easy, very simple, and rather effective!

WARNING: If you do this, remember that there are tens of thousands of volts pulsing on these things. So, when the engine is running,DO NOT put your fingers ANYWHERE NEAR!!!!!! Seriously, you will only do it once.

The effect is quite good, I think!

I also replaced the oil filler with a Vintage Speed stainless filler and breather can, but this was just a bolt on part and not worth talking about.

And that, ladies and gents, is how you dress up a tatty engine! A little creativity, elbow grease, and using readily available materials and you really can achieve "old skool" effects that can definitely hold their own with modern "Need For Speed / Fast n Furious" style cars done in LEDs and fibreglass that the younger generation enjoy running around in.

I hope this sows some seeds of inspiration for you!

Step 9: The Finished Engine

And this is how it looks back in the car.

Finished, for now!!


Added a couple more pictures after the car was painted (see my other Instructables!) that really who the engine off in all it's glory.

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