Repair of spark plug hole in Zetec 2.0 DOHC Repairing Sparkplug threads on the Zetec. When I bought my Zetec-powered Focus I did not know there was a ticking time bomb in it. That bomb? #1 cylinder plug hole had been stripped by a prior fumbling mechanic. I don't know what he did to "fix" it but I'm guessing JB Weld on the threads of a replacement plug. Or something. It held long enough for me to buy it and drive it home and use it for a few months. Then one day "boom" #1 plug was ejected from the engine - when I was over 200 miles away from home. There was enough thread left to thread a new plug into the hole and drive the car home on 3 cylinders with the plug wire disconnected. When I got it home I had to repair it. Here is how I did it. Here are some of the links I used: Another Timing Belt Change: http://www.focusfanatics.com/forum/showthread.php?t=198223 How does timing pin work? http://passionford.com/forum/technical-help-q-and-a/302763-how-do-u-use-the-zetec-camshaft-timing-locking-kit.html Changing Zetec Camshafts http://ford-force.forumotion.com/t52-changing-zetec-camshafts 200 BHP version of the 2 ltr Zetec http://my.voyager.net/~quadrant19/XF-to-Zetec.html Tuning the Zetec http://www.zetecinside.com/xr2/zetectune.shtml Engine Info Zetec http://web.archive.org/web/20051102085444/http://www.mwstewart.co.uk/index.php?content=cars_zetec_engine I also used the Factory Service Manual which is on CDROM. Head shop that did the work: Bearing Service Co 1040 Northwest Everett Street Portland, OR 97209 Parts needed and prices 2013 January: Head Gasket O'Reilly Auto Parts - individual Fel Pro part# 9005PT $36.99 Head Bolts O'Reilly Auto Parts - Fel-Pro part# ES72175 $16.99 Note that there are standard hex headed torque to yield bolts available for this engine. However, I will point out that the force needed to break out the existing head bolts and remove them is so great that you really have to get a high quality torx bit or you risk breaking the bit and leaving pieces of it in the engine. So, once you buy that bit, you don't need the hex headed TTY bolts, and they are more expensive anyway. It seems pointless to me to spend extra money on single-use hex headed head bolts just so the next guy to work on the engine doesen't have to buy the expensive torx bit. Torque Angle Tool - $9.95 Autozone Torque wrench: I prefer a beam torque wrench, particularly for head bolts because the beam wrenches basically don't go out of calibration. Proper use of beam torque wrench: 1) Pull to fastner torque then stop pulling, do not keep pulling past torque 2) Balance the handle when reading scale (handle should be centered on the pivot pin) 3) Don't let needle drag on scale 3) Approach torque gradually ) pull not push wrench 4) Clean dry threads, unless manual specs otherwise, blow out threaded holes with air 5) Position yourself properly to avoid parallax error helicoil vs plug insert. Back in "the olden days" there was only 1 way to repair a stripped spark plug thread. You pulled the head off the engine, got out your welder, welded a bead over the threads, then redrilled and tapped. Most people didn't do this. They just chucked the head and got another one from a wrecker. Then the Helicoil was invented and everyone used them. Then, years later, they invented spark plug thread inserts. Thread inserts, like the Timesert, used with care, allow a plug hole repair to be done while the head is still on the engine IF the plug threads are accessible. The usual procedure is they stuff an oily rag down the hole into the cylinder (with the crank turned to the piston at the bottom of the compression stroke) then drill and tap in the insert, then use compressed air to blow the cylinder out as much as possible then pull the rag out and use more compressed air. Some mechanics might run a boroscope down there to make sure all metal fragments are out. Ford prefers inserts and dislikes helicoils. In fact they have issued a TSB - #15815 - for the larger V6 motors used in Mustangs saying to NOT use them, and they have also issued a SSM - #18310 1995-2005 - stating to not service stripped plug threads with helicoils in ANY engine. Why does Ford dislike helicoils? For the following reasons: 1) The helicoil hole must be drilled and tapped perfectly parallel to the old hole or the plug will not seat and seal. 2) The helicoil should be locked into the head with Loctite 620, the high temperature product 3) The helicoil must be installed so that none of it projects into the cylinder. The breakaway tang on the helicoil must not be allowed to fall into the cylinder or it will likely scratch the cylinder walls 4) the plug MUST be retorqued after the engine is run, the expansion and contraction rates of the different materials and the settling of the helicoil into the aluminum head will loosen the plug. Run the engine 25 miles and recheck torque when the engine has cooled down stone cold, then for the next month periodically check the plug torque in the morning before the engine is run, until the plug holds torque. In my case I had to tighten the plug 6 times before it finally held the proper torque value. All of these reasons pretty much require that to properly install a helicoil insert it won't work unless the head is removed and the plug hole tapped in a fixture, using a drill press and pilot shaft to line the head up to the drill and the tap. In other words, a mechanic leaning over the head with a hand drill will almost certainly go in crooked, or the bit will wander and the helicoil will not go in aligned. the spark plug inserts DO NOT require head removal for most heads, and the insert can go in slightly crooked and still seal. Also I would guess that retorquing is not needed except maybe once. Those 3 reasons are enough to understand why a manufacturer would prefer an insert over a helicoil. However, the Zetec head has the spark plugs so deeply recessed that I very much doubt that an insert can be safely installed in the head with the head on. None of the machine shops I called would do this repair with the Zetec head on the engine. I went with the helicoil rather than an insert. Since the head was going to be off, the machine shop could insure the insert went in properly. It also meant as little material removal as possible would be needed, and there would be no interference when using the Motorcraft plug. fig1 2003 Ford Focus fig2 Ford Focus with 2.0 DHOC Zetec transplant fig3 Here is the setup used - positioning in the garage fig4 Just barely enough room to get a floor jack under the car. Raise car. fig5 Drain the coolant fig6 detach brake booster pipe from intake manifold (this is easiest from the bottom) fig7 disconnect oil pressure switch sensor (right behind alternator) fig8 remove air cleaner housing Pull top portion of timing belt Remove passenger side wheel Remove wheel splash shield loosen bolts on water pump serp pully remove serpentine belt and remove 4 bolts left hand timing cover remove all bolts valve cover and give it a gentle wack with a soft rubber mallet it will pop off remove all spark plugs insert screwdriver in #1 plug hole and turn engine with rachet until at TDC and cranks are aligned so a timing bar will go in the ends. pull bar remove crank pully with impact making sure not to turn crank - reinsert timing bar support engine oil pan with wood block on jack and raise engine remove engine mount remove mount studs from center timing cover remove top timing cover reinstall engine mount and remove jack dab paint to mark pully positions loosen cam belt tensioner all the way slide top belt off pullys and lower car. remove cam cap bolts with E10 torx socket. fig9 detach accellerator and cruise control cable fig10-fig11 detach EGR valve and pipe bracket - also detach second pipe bracket in front fig12 pull off vacuum hoses fig13-fig14 disconnect fuel injector wiring fig15-fig16 disconnect camshaft position sensor fig17-fig18 disconnect fuel injector connector & ground connector fig19 remove heat shield fig20 detach thermostat fig21 remove catcon nuts and loosen catcon and exhaust bolts in exhaust line to allow catcon to hang down from car. fig22 detach power steering pipe bracket and oil level indicator, remove oil level indicator handle fig22a detach spark module and move to the side fig23 detach power steering pump bracket fig44 closeup of generator bracket fig76 remove valve cover bolts. Plastic valve cover is now free but is likely going to be stuck on the head. Give a gentle wack with a rubber (soft rubber) mallet and it should pop free. remove cam cap bolts. These are reusable but only 3 times (according to the factory service manual) Your supposed to punch-mark the heads if you reuse them to indicate to any following mechanic that they were removed and replaced. A good E50 torx socket is critical - Sears sells a set - and if you must replace the bolts then Massive sells a set here http://massivespeedsystem.com/_massive_speed_system_/massive_cam_cap_bolt_kit/mahw8592/i-252276.aspx remove cams - the end cap closest to cam may be stuck on - if so, give it a wack with rubber mallet or brass hammer then carefully put a blunt screwdriver into cap gap and lever up. (don't want to scratch the head surface) Make sure to note which cam is intake and which is exhaust. As for engine timing: The FSM states that you must go through the retime procedure for the engine. This uses a timing pin that is inserted into the bolt hole I marked. It is also possible to use a dial indicator to find TDC in the #1 cylinder and set the timing from #1 spark plug hole in the normal manner, since the plug is mounted exactly centered above the piston. figtiming.jpg In my case I did not wish to buy the tooling for this or mess around with the cam timing, I also did not want to pull the engine mount and all timing covers from the engine. So I carefully noted the positions of the cams, using paint marks, and counting the number of timing belt teeth between the wheels, noted the position of the cam belt tensioner, and with the tensioner loose, carefully pulled the timing belt off the top timing wheels, then unbolted the cams after removing the belt. The cam oil seals are large enough so that they can be removed and replaced with new ones while the cams and sprockets are off the engine, without unbolting the cam sprockets from the cams. I was careful with reassembly and the engine retained it's timing. it's critical to take many digital pictures of the belt before removing it from the engine. remove head bolts - this takes a Torx 55. Sears sells 2 Craftsman sets of Torx - one is a 3/8 drive and one is a 1/2 drive. I don't think the Sears 1/2 drive set is small enough to get down into the access hole to get at the head bolt. The best tool is one that Mac tools makes, it is an extra long Torx with a 3/8 drive. The Torx bit must be held perfectly in line with the bolt - I used a 3/8in to 1/2 adapter on a Craftsman extra long "flex handle" you could also use a 3/8 breaker bar. These are Torque-to-yield and must be discarded. NAPA also sells a single Torx T55. Don't use a cheap torx bit like one from the sets of 1 piece Torx bits that Lisle makes. Use Snap On, Matco/Craftsman, SK, etc. if you do buy the Mac tool it may not work very well for torquing on the new bolts as it may put the torque angle guage too high so you may need the smaller 3/8 drive torx bit. fig24-fig26 remove tappets and keep separate and note where they came from fig27 attach engoing hoist to lifting bar, attach lifting hooks on bar to engine lifting eyes. Apply gentle lifting force with the hoist and use a prybar and a block of wood to pry up on the exhaust manifold. You will hear the front of the head detach from the gasket. Remove prybar and crawl under car and reach up behind engine and gently push up on the plastic exhaust manifold, you will hear the back of the head detach from the gasket. Gently lift head with the hoist making sure to move hose and wires out of the way. When head is off vehicle, detach intake and exhaust manifold. fig28 There is a temperature sensor that has a connector attached to a plate on the underside of the intake manifold, and the sensor is tightened down on the block, under the manifold, the factory service manual did not mention this sensor. In my case the lifting action on the head severed the sensor wires - fortunately repairable. fig29-fig39 detach intake and exhaust manifold and take a lot of pictures to note where the bolts are - on my intake 2 of the bolt holes were covered up on the plastic intake and did not have bolts, but the threaded bolt holes still existed in the head. fig40 check condition of the cylinders and pistons fig41-fig42 headgasket used. Now that the gasket is out you can order a replacement gasket fig43 location of PVC valve. Now that the head is it this is easy to get at - replace it. fig45 remove the catalyatic converter gasket and replace with the new gasket that comes in the gasket kit fig46 This is the engine block after the remains of the old head gasket have been laboriously razor-bladed off. Cylinders 1 and 4 are at TDC. The surface of the cast iron block is stained but it has all old gasket material removed. Fig47-fig these pictures are after comiong back from the machine shop fig47 Exhaust port side of the head, after it has come back from the machine shop fig48 Closeup of the casting number on the exhaust port. The -AC indicates it's a version "C" head, this is needed to get the correct gasket kit fig49 closeup of the front of the head fig50 Intake manifold side of the head fig51 back of the head - coolant connection - I don't know if the "A" means anything fig52 Another casting mark - I don't know if the "C' referrs to the head version C or something else. You can see the top of the repaired sparkplug hole fig53 This is the bottom of the repaired plug hole showing the helicoil fig54 This is a spare plug in the next cylinder with intact threads showing the hole depth. fig55 These are the new plugs that I'm putting in the engine, this is the factory callout plug. fig57 THis is a comparison of the NGK plug for this application and the Ford plug. The helicoil repair allows use of the Ford plug. When I bought this car 2 years ago one of the first things I did was replace the plugs. The engine had the original Ford plugs from the factory in it. At the time I didn't know to use the Motorcraft plugs so I used the NGK plugs. I don't want to say that the NGK plug was the cause of the plug being blown out of the spark plug hole because I actually don't think that was the case. But, it is clear in a side by side comparison that the NGK plug electrode does not project as far down into the combustion chamber as the Motorcraft plug - these are not identical plugs and I don't think NGK should list them as interchangable. Fig56 Closeup of the NGK plug fig54 This is a bottom view of one of the used NGK plugs screwed into cylinder #2 fig58 This is a bottom view of the Motorcraft plug screwed into Cylinder #2 notice how nicely it lines up. fig59 This is a bottom view of the same plug screwed into cylinder #1. Notice that it projects down an additional amount into the cylinder. This is, in my opinion, why I had the plug blow out of cylinder #1. I believe that when I removed the plugs 2 years ago and replaced with the NGK that there was carbon buildup on the bottom thread of the plug. When I unscrewed the plug it dragged that carbon back up the threads and damaged the plug threads on the way out. It is clear from the positioning of the plugs in the remaining cylinders that this is a manufacturing defect in the cylinder head. fig60 Closeup of the plug in #1 cylinder fig61 Checking the fit of the new head gasket Fig62 Closeup of the FelPro part number on the new gasket Fig63 Comparison of the Felpro headgasket and the original Ford headgasket that was on the engine. The only difference is the rivits. On the Ford gasket there's an extra rivet in the middle of the top and the bottom left and bottom right. On the Felpro gasket the bottom rivet is in the middle. Fig64 Closeup of the gasket number on the Ford headgasket. fig65 Closeup of the Zetec head intake Fig66 A second closup of the Zetec head intake. I put these 2 shots in to show that not a lot of porting work can be done with this head. Fig67 The intake manifold with new gaskets from the gasket kit, right before mounting on the head. fig68 Attach the camshaft sensor and the antiknock sensor first, before putting back on the intake manifold fig69 Here is my fix to the infamous "collapsing PCV hose" Ford used this weird hose arrangement where the PCV hose is one size until it gets to the manifold then it is expanded out to a larger size. There is a weakness at that location and when the hose is positioned properly it collapses there and cuts off the flow. The hose clamp prevents the hose from collapsing at that point fig70 Since everything is off it's easy to replace the PCV valve, now's the time to do it fig71 Here is the repaired sensor - I think this is a block temperature sensor or something like that. There was no mention of this sensor at all in the FSM during dissassembly and as a result I broke the sensor wires off the sensor when lifting the head off the engine. Fortunately the break was repairable, I resoldered the wires and put shrinktube on them. fig72 - fig73 Inspection photos of plugs - I tightened the plugs into the head before mounting the head on the engine. Not the smartest thing as I realized later this would make it difficult to check timing. make sure to clean the plug seating area of carbon. fig74 - fig75 Lowering the head back on to the engine. The timing belt idler wheel is tightened down. I left the exhaust manifold off to make it easier to see when I had lined up the head. fig76 Here is a shot from the bottom of the engine looking up, this is showing where that sensor with the broken wires is located. The bracket that holds the sensor connector is attached to one of the intake manifold bolts. fig78 Here is a comparison of the old head bolt and the new head bolt. On the top is the Ford bolt and the bottom is the new FelPro bolt. While the threads are identical it is interesting to note that the shank of the Ford head bolt is slightly thicker. You can see that the stretch on the old bolt is very small fig77 Here is a comparison of the old head bolt and the new Felpro head bolt that shows the stretch that has happened with the old bolt. Since they are side by side and the threads are meshed it is clear that the old bolt has stretched. fig79 This is the box the new head bolts came in. fig80 Here is the Torx bit that I used to remove the old head bolts and install the new ones. This is a T55W that I boought for a buck or two from a used tool place. It's a P brand Fig81 The head bolts have to be torqued down in sequence, and to 3 torque levels. This is my 3/8 beam wrench I used to get them to 20Nm Fig82 This is my torque angle guage used to put the final 1/4 turn on the bolts. Under this is a 1/2 to 3/8 adapter. This worked well with the T55 bit, just the right length with the adapter and the bit. This is at the beginning of the last turn fig83 This is at the end of the last turn. fig84 All bolts are tightened and the tappets are reinstalled, this is the last picture. Reassembly is basically in the reverse order of assembly. Install the cams, then the timing belt then put the cover back on and bolt everything back onto the engine. You should check clearance between each lifters and the cams. Refill the cooling system by pouring antifreeze into the heater hose until it comes out of the fitting on the thermostat housing then connect the hoses and fill the overflow tank. For the first 25 miles try to keep the RPM under 2000, then check the spark plug torque and tighten if needed. Check in the morning when the engine is stone cold. Continue checking the plug tightness every few days until none of them are loose. In my case the repaired plug was down to 10Nm of torque after the first 25 miles. It took about 5 mornings checking with the torque wrench in the morning before the plug held the proper torque.