Technical: Engines; why and what we do to them.

Quality, you get what you pay for. Sorry, not the most exciting of posts, but if you’re thinking of buying an engine from here then…

This is about why and what goes into a full professional build. Here is an explanation, starting at the top of the engine and working our way down. It’s about leaving the bits that don’t need doing and modifying or replacing the parts that do. You’ll then get a better quality job and save a lot of money, both in the short and long term.

Dipsticks. There is a lot of confusion over dipsticks, not only on stock 2.0 (see appropriate blog), but even more so when a swap is done. I either use a 2.3, 2.5 or a 2.0 cam cover, whichever I have an excess of or is easiest/best condition. The length of the new dipstick/camcover combo is checked against the original so the max level remains correct. Simple isn’t it? Well yes, so I don’t know why so many get their pants tied in a knot over it. If you buy an engine from me you can be sure it was considered and something done about it, no guesswork was involved or asking people on FB and getting 72 different replies, none of which can be substantiated and ordering special dipsticks from the US.

Or even worse, running low on oil on track! Spend the money on something worthwhile, because when you consider what you’re doing it’s nothing more simplistic than dangling a stick into a pool of liquid to check how deep it is.


If the engine is built with high power in mind then it really does pay to upgrade to larger injectors early on. What I mean by that is the originals will cope ok up to about 230bhp, but will be flat out at that with no room for power related upgrades (such as ITBs). We generally fit new Bosch 550s.

This is mainly due to the fact we are using the factory ECU. You need to tell the ECU that the engine size has gone up and also the injectors are larger, once you’ve done that it’ll perform much better (the engine will act like a standard one at low rpm, idle, cruise etc), you need certain Ecutek permissions to do this so it will already have been done when you buy and engine & ECU combination from us.

Cylinder head.

Is completely stripped, cleaned and assessed. I have the tools and knowledge to check for wear in the various moving parts. If new valves aren’t fitted then the old ones are always cleaned up as new, seat face recut and an extra angle put on to aid flow.

What is done to the ports is obviously down to the spec of the whole build, but again I have the wherewithall to improve the flow quite easily so quite often a mild job is enough. Valve seats are always recut. EGR passageways are blocked off.

When cams are fitted I never rely on the slots at the end and always use a dial gauge to check lift at TDC. You really need to have some figures to work from and can never trust with 100% the cam manufacturer got it right.

Pistons. Pretty rare I use the orginals unless asked to do so or on a budget build. Mainly because the compression ratio is too low. Whilst putting a bigger cam in a std CR engine will see some kind of positive result, matching a big cam with high CR is a marriage made in heaven. This isn’t the time nor place to go into this extensively as it’s really a discussion all of it’s own, but doing it the proper way will not only make more power and torque (at every single RPM) it’ll also see better MPG. People get to thinking it’s all about some dick waving peak BHP figure yet it isn’t. It’s more about how an engine performs at idle, at low rpm and mid range too. ‘The area under the curve’ is very important and once you’ve driven a properly modified engine it will become very apparent.


For the price you can get a decent set of forged ones for it just is not worth using the originals. The engine is in bits in front of me so the labour factor is zero.

Crank: Gets cleaned, polished and oilways modified for improved oiling. The jury is out on the effects of removing the BS ring gear. The pulleys on an MZR/Duratec engine are of the floating variety, that is they have no keyways to locate them, you can spin them round and only the end bolt and often a diamond washer hold them from moving. This is ok for the cam sprockets, but the pulley on the crankshaft is known to move under duress. We therefore key the pulley to the crank to stop this. It also means taking it off (especially whilst in the car) is a lot easier. If it does move pistons will hit valves:

The block gets a clean and check like everything else and any unwanted holes blocked up. You can buy kits to do this, but as I have the equipment in the shop to do it quickly and properly there would be no point to buy something which is aimed at a DIYer with no tools. Some time and money saved there.

The bores are often re-bored and honed, if they are then a deckplate is used. This allows me to run the piston to bore clearance really tight. Less piston rock, no piston slap (a knocking noise when cold) and more power, less wear due to components fitting together properly.

The tumble flaps are removed and the housing gently blended in internally to aid air flow.

I think that more or less sums up a full build, it’s always good to know what you’re getting for your money.

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