Engine Reconditioning

I've had a couple of people ask about the process of reconditioning the Fiesta ST150 Duratec 2.0L N4JB engine destined for the Fury. Although the rebuild isn't yet complete (awaiting the final steps of fitting the Raceline sump, timing chain cover, crank pulley and ancillaries) it is the second reconditioned Duratec I'll have built. The first being the 2002 Mondeo 2.0L CJBA (lo-port) engine used in my Tiger Super 6.

Worth noting that the Ford Mondeo MkIII Haynes manual, that I have, states that the Duratec bottom end has 'no serviceable parts' and must be replaced with a whole new bottom end from Ford... oh no it doesn't!

To give the full history I located the engine on eBay as an accident damaged engine (for spares). The damaged to the engine was where one of the lower drive shaft mount bosses on the block had been torn off in the accident.

Once the engine was collected the first job was to strip it completely and have the block welded and then checked by my local machine shop. Happily the engine block repair was given a clean bill of health and then the cylinders de-glazed along with the block, pistons and girdle cleaned (hot dipped). At the same time the crankshaft, flywheel and clutch cover were balanced as an assembly (in the same way as the CJBA had been).

With the block away being looked after at the machine shop worked started on the cylinder head. On the N4JB this is the 'hi-port' head meaning that the inlet port tracts are physically taller and as a result flow better (apparently by 10-15 BHP - I've not yet confirmed this myself but plan to find out with the Fury).

Cylinder Head

With the head stripped down all main parts were cleaned using Nitromors paint stripper (does a great job on built up carbon and I prefer it to wire brushing etc.). The only time when abrasion was needed was with the carbon on the valve heads themselves (to due the temperatures involved). By putting the valves in a pillar drill and using oil and emery cloth the carbon deposits were reasonably easily removed (taking care not to make contact with the part of the valve stem that runs in the valve guide).

Then the delightful job of lapping in 16 valves - a valve lapper drill attachment makes this job slightly more bearable (loaned by my friendly 'unpaid helper'):

The thing with valve lapping is that the inlets are usually quick and easy to get to where you want them - a little coarse grade paste then a few times with fine... The exhaust valves, on the other hand - lots with the coarse grade paste and then more than a few with the fine! It's nice in the end when they're all done though.

Then came the process of fitting new valve stem oil seals - green for inlet and black for exhaust:

Valves refitted with the trusty valve spring compressor:

With all the valves in place next step was to fit the buckets, camshafts and caps although only a trial fit to establish the valves clearances (lobs to buckets). Camshaft caps tightened in sequence and in stages to the specified torque:

Carrying out the procedure for measuring and establishing the valve clearances requires a lot of patience and care (along with a good whiteboard to write all the numbers down):

Once you've got all the clearances you take it apart again. Out comes the camshafts (again in loosening sequence and stages) and one by one remove, measure and record the bucket sizes (not relying on the marked sizes). Then a bit of maths and fiddling around with available sizes of buckets to hand (including ordering some new under size ones where necessary - Cosworth better value than Ford) you end up with the clearances within the required tolerances:

Just put it all back together again and double check the clearances to make sure your maths is good.

Engine Block

Engine block, crankshaft, pistons, flywheel and pressure plate back from the machine shop. Engine block looking nice and clean and with the glaze removed from the cylinders. First job was to get it mounted on the engine stand ready for work to begin:

Assembly begins with the main bearings fitted. Parts ordered from Burton Power. Standard size and standard duty Mahle main bearings but standard size heavy duty Cosworth big end bearings:

Only problem was that the main bearings were shrink wrapped together and in transit they'd knocked against each other damaging the surfaces:

Burton Power sent replacement very quickly and originals returned and refunded.

Main bearings then fitted although, all except centre top bearing, have no locating tabs/mechanism so the vernier calliper is needed to locate the top and bottom halves of the bearing accurately (a right pain to do). At the same time engine assembly lube carefully used - making sure none makes it's way onto the outside of the shells otherwise they could spin I guess:

In goes the crankshaft, taking care not to disturb the upper main bearing shells. Also carefully lubed again:

Note: Bottom left corner of the photo shows the nice job done in terms of aluminium welding the boss back on that was torn off in the original car accident.

Preparing the 'girdle'. This is a nice piece of engineering in the Duratec. Instead of individual bearing caps this part provides all lower bearings and helps with bottom end rigidity. On the LHS of the picture you'll see the home made alignment tool bolted to the girdle itself. This is used to ensure the girdle is aligned with the block and therefore gives a square mounting surface onto which the rear crankshaft oil seal assembly is attached:

In goes the girdle, again taking care not to disturb the carefully positioned lower main bearing shells:

Decided to reuse the original Ford main bolts, as had been done with the CJBA engine. These are stretch bolts and are recommended for a maximum of 3 uses (IIRC). The bolts were checked visually and for length etc. Torqued and then 90 degrees (IIRC) - again the home made alignment tool can be seen in action:

The original standard pistons were fitted with new rings, carefully done on the bench and the big end bearings, again using a vernier calliper to get the shells in the correct positions in relation to each other (since no locating tabs). Also needed to make sure the rings were fitted in the correct orientation and with the ring gaps in the correct positions around the piston. Not too much engine assembly lube and then into the block, rings compressed, piston correct way round and taking care not to 'ding' the cylinder wall with the connecting rod on the way in:
Use of a spare piston to carefully push, evenly, the piston down the bore until the rings are all in the bore itself:

ARP big end bearing bolts fitted, based on the instructions - including the ARP fastener lube. Then all torqued up and ready to go:

Oil Pump

Quick detour to strip, clean and check the original N4JB oil pump. The oil pump front cover can be split from the pump body by carefully drifting it off its pegs using a long bolt and nut carefully applied to the tabs on the edge of the front cover. Fit a bolt into the of the pump drive shaft (sprocket removed) and then use this to hold the pump vertically in a vice.

Using the bolt and nut carefully tap, turn, tap, turn etc. until the cover comes off:

This what's inside once the front cover comes off:

Cleaned, lightly oiled and then reassembled the clearances were then checked. Outer rotor clearance (nearest feeler 0.063mm):

Inner rotor clearance (nearest feeler 0.063mm):

End float clearance (nearest feeler 0.076mm):

Oil pump front cover loosely reassembled and oil pump fitted to block. The four mounting bolts were then used to evening pull the front cover closed:

Back to the Block

Rear crankshaft oil seal assembly fitted. Shown in the following photo the white oil seal protector used whilst fitting:


Raceline lightweight flywheel and ARP flywheel bolts. Note the spigot bearing is fitted but it turned out to be the wrong way round - not easily sorted without a spigot bearing puller! (but it is sorted now):

To tighten the flywheel bolts I came up with a homemade flywheel holding tool that I can leave in place (cylinder 1 @TDC). Teeth cut to roughly match the flywheel and MIG welded:

This allowed the ARP flywheel bolts to be torqued up in a diagonal sequence.

Build Up Continued...

Next 'on with the head'. Two old cylinder head bolts with the heads cut off are great for helping to align the head as it is lowered onto the block (didn't get a chance to take a photo of this though sadly). They're also useful for ensuring the threads are clean in the block itself.

Cylinder head, minus cams and buckets, lowered carefully onto the block. A small amount of sealant is needed on each side at the front where the edges of the timing chain cover meets the small gap between the head and block (this is to ensure no oil can track along this small gap). New cylinder head bolts (stretch type) fitted and torqued up in the prescribed sequence:

Next in go the buckets, following the earlier sizing/clearance work, with a small amount of engine assembly lube (more will go on the cam lobes):

All buckets in place and ready for the camshafts:

In go the cams, again well covered with assembly lube:

Both cams in and bearing caps in place - just need tightening in sequence and to the correct torque (hopefully for the last time!):

On go a number of ancillaries. Water distribution block, coil pack and coolant temperature sensor:

More ancillaries fitted - thermostat housing, oil separator, water bi-pass hose, EGR blanking plate and knock sensor:

Cam cover loosely fitted to stop debris getting in. Suzuki GSXR 1000 ITBs mounted 'direct to head' via a design of my own employing a 10mm thick aluminium adapter plate and using the original Suzuki rubber inlet mounts - the adapter plate drilled and tapped to take the runner inlet mount bolts. Masking tape left in place for now to stop debris getting into the cylinder head. Modified fuel rail also final fit:

Also shown in the above photo is the standard sump fitted loosely just to keep debris out of the bottom end.

Attention turned to the front of the engine with new parts ready to be fitted. Oil pump drive fitted = crank sprocket (rear teeth), oil pump sprocket, oil pump chain guide + tensioner and then oil pump drive chain itself. In front of that is the camshaft drive fitted = crank sprocket (front teeth), camshaft sprockets (losely fitted for now), cam chain guide + tensioner and then camshaft drive chain itself:

The Raceline sump can be seen losely fitted for now in the above picture. The following shows the inside of the sump with windage track and crankshaft scraper. All cleaned and ready to fit (blown out with an air line):

Next engine inverted, cleaned up the mating surfaces and carefully applied RTV sealant - "not too much but just enough...". At this point the timing chain front cover is on but not sealed - this is to provide an alignment guide for the sump to be bolted to and ensures it is square as the sealant cures:

Sump then lowered into position, avoiding smearing the sealant, cap head bolts fitted and torqued up - also shown is the Raceline oil filter housing fitted with new gasket:

Once the sump sealant had cured the timing chain cover was readied and again RTV sealant applied (note the crankshaft seal is missing since this is better fitted once the cover is on):

Cover fitted and torqued up - just cleaning off the sealant that's ouzed out (this can be done once cured but one less job for later):

Forgot to get a shot of fitting the front crankshaft seal. Cranshaft pulley in position and ARP lube on the surface where the crank pulley bolt makes contact. Also shown is an M8 bolt used to position the crank pulley in relation to the crankshaft - much prefer a keyway..! Remember not to leave the bolt in whilst tightening to full torque...:

ARP crank pulley bolt all lubed up. Lube under the bolt head, under the washer and on the threads:

Crank pulley bolt torqued to 150 lbft. Also shown is the Crankshaft position sensor alignment tool doing it's job:

Final jobs relating to camshaft timing. Not shown but there are slots in the rear end of both camshafts into which a bar is fitted to confirm the correct timing. Shown is a nifty tool I sourced for loosening/tightening the larger camshaft sprocket bolts with the timing chain cover in place (this is a fuel injector removal socket from Sealey):
N4JB engine rebuild complete!

Government health warning:

Note all information provided is for the interest of the reader and is in no way a recommended approach etc.

Please seek expert advice before attempting any of the work shown and take appropriate safety precautions.

Thanks for taking the time to visit this page!

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