how hard is it to swap a focus sohc to a dohc
9 Answers
Its not the easiest thing in the world and it will either be a lot of work (if you do it yourself) or a lot of money (if you pay someone). we did it in a friends (an SPI SOHC to a ZX2 Zetec DOHC motor). we did this on a 2003 focus. The basics are as follow, you will have to change the motor (duh), the ECU (computer controlling the motor) both sides of the engine harness (in engine bay and in car), the motor mount on the passenger side only, the alternator and power steering pump, AC compressor needs to flipped over, exhaust up to cat needs to be changed, flexplate is different on auto trannys, tranny sub harness will need to be changed, throttle cable/cruise control, serpentine belts, air intake and a few misc. tubes/hoses. I know it looks like a lot but really its not too bad, most of the stuff should already be on the motor if you get it out of a junkyard. Oh and be careful with the Passlock module in the computer...or else the car wont start and it costs a fortune to get a new key/module at the dealership. good luck with everything, hope this helps.
I"ve been looking into this and have decided to pay someone to do it for me. I found a shop near Green Bay WI that has done this at least 30 times and have it down to a science. I'm looking for someone within 200 miles of Minneapolis MN that can do this. Is there anyone out there that can do this for less than $1500 parts and labor?
thanks good imformation , any video how to rebuilt the engine split port ford focus 2002 ?
If you are planning to rebuild the SPI engine after dropping a valve seat (typical failure) you need to check how badly the engine was damaged. If your pistons are all still intact and not broken you will have a pretty good chance at only removing the head and having it rebuilt. But make sure it is rebuilt by someone who is familiar with what they need to do to fix the factory mistake of the loose valve seat press fit clearance on all the valve seats. You also need to check the head for cracks and other damage caused by the dropped seat. If your piston is broken chances are your engine block is damaged by the piston connecting rod flopping around inside the bore and pounding the cylinder so far out of round it is too expensive to repair because it needs sleeving. Good Luck. AZ
Cyrl is talking about the ignition electronic recognition system that is part of the ECU unit. The ECU needs to be changed when going from the SOHC to the DOHC engine so the key that matches the new ECU needs to be moved over to the receiving car. Other wise if you don't use a key that matches the ECU Passcode it won't start, I don't think it will even turn over. Cyril seems to indicate that the passcode module may be separated from the ECU but I haven't heard that. If you don't have the ignition key that matches the ECU passcode the dealer can program a new key for you I think it costs about $50 to $100. It hope that helps.
Um they are separate I think but in the same plastic holder peice I ended up doing all harnesses cause my Donner car had power evert hint and my first car didn't
I am currently doing one of these swaps, do I need to swap the whole ignition system like the tumbler and stuff? And do I need to do the wiring harness behind the dash on the inside of the car or just the engine bay and what’s on the engine?
You don't need to change the dash wiring. Just use the ignition switch from the donor car so your donor car key works. Otherwise you should be able to take your donor car key to a hardware store and have them make you a key with your original key tooth pattern but with the donor car pass code thingy in the key. That will cost you about $50 for a "smart key". The problem with that is that (mixing the teeth and the smart thingy) now you will have an "orphan" key set and if it gets lost, you can't replicate it by just using a VIN number. If you use the donor key set "as is" you will be able to make a working key by giving a Ford dealer the donor car VIN. Also, one of the main things with the chassis wiring in the engine bay and body is that the donor car (DOHC) has to be the same year as the original (SOHC) car . That will make your life much easier. There are some wiring differences between years even though the plugs still fit. These wiring differences can be "fixed" but you need the wiring diagrams for both years and compare each wire in the harnesses and moving them as needed. The guy that did mine ended up causing a fire in the dashboard because the years weren't the same. Good luck with your project. You might want to consult with the guy I mentioned in Wisconsin who has done a lot of these. I think the shop name is SpeedWay motors near Green Bay Wisconsin.
