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Discussion Starter · #1 ·
greetings to all.

since there is not much documentation on the subject, I decided to create this topic with the details and the progress of my cylinder head exchange (12v to 16V) while keeping the same cylinder block (original connecting rods pistons and crankshaft)

does this work in F2T ?

it may work but connecting rods, pistons timing belt and camshaft sprockets are required.

-Why don't you simply perform the full FE3N swap ?

In my country this engine is quite rare to get and if you manage to locate one, it is not usually legalized (in my country it is mandatory to legalize the swaps).

-12V FE motor ?

For my country, Mazda decided to sell a FE 2.0 version with 12V cylinder head and carburetor that delivered an astounding 89 HP. That is the engine that will be used for this conversion.

-It is cheaper to turbocharge the 12V Sohc.

It is true, but it was not very reliable, I lost count of the number of spark plug wires I changed, not counting the ignition problems due to high temperatures in that area of the engine. This engine had installed a Holset HX30 at 15psi with its RC oem (9.5:1).

Well, let's start with a list of necessary parts:

-Complete FE3N Cylinder head (Kia or mazda version).
-Water pump KIA.
-KIA Crankshaft Sprocket.
-KIA timing belt.
-Programmable computer (megasquirt, speeduino,Fueltech ETC).
-Cylinder gasket kit for KIA (manifolds , retainers, valve cover seals, etc.).
-SOHC cylinder head gasket! can be Mazda, felpro, fraco etc.).
-KIA head Bolts.

The first step to do is to modify the cylinder head, SOHC cylinder heads have a huge central oil drain and 1 at the end. While the DOHC version has 4 oil discharges.

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16V head On SOHC Block
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What to modify:

plug with welding the excess oil drains.

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material must be added in the central part or else we will have an oil leak through the cylinder head gasket.

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Mazda did not use 4 oil drains because it wanted to, they exist for a reason, so now we are going to create an external oil drain back to the oil sump.

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after you have your modified cylinder head ready to mount, proceed to install it as you would have done with the SOHC cylinder head.
I recommend using 67 lb/ft as the manual says if you go without turbo, but if the goal is other :devilish::devilish: (which is why pistons are not changed in this construction) torquing to 75 / 80 lb/ft would be a good idea.

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At this point, you will have bolted the DOHC cylinder head (aka FE3N) on your SOHC block (FE, F2, F8, F2T).

In the next update, I will explain the mounting of the timing distribution and the options for the intake manifold.

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Cool build. This has been done and posts have been made about it on this forum but I am sure they are hard to find and the pictures are gone.
I do hope you are planing to turbo charge this motor and assume the devilish faces mean you are.

You can achieve equal or greater clamping force to a head or part while applying less torsion to the bolt:

I would say not torquing head bolts to 75 or 80 ft-lbs is a good idea, there is a point/rating for each bolt at which clamping force is no longer completely applied to the head (or whatever) and the torsion starts stretching the bolt and threads.
I recommend reading this Reduced Torque with Lubricated Bolts and using it to apply more clamping force to the head while taxing the bolt less. They do state *"Note that if torque specified for a dry or slightly oiled bolt torque is applied to a lubricated bolt - the bolt may overload and break."
If factory specs are with engine oil work up the chart for lubricant.
The chart shows that clamping force can be increased from 30 to 55% while respecting factory torque values.
With an original torque value of 69 and a new torque value of 80 you are looking at a 14.7651 increase in clamping force.
By lubricating the bolts the friction at the threads is reduce thus requiring less toque to achieve the same tension on the bolt.
If SAE40 is used as lubricant a torque reduction of 30-40% is require from the dry torque specs, so 48 to 56ft-lbs would yield the came clamping force as 80ft-lbs dry.
Although they state *, all toque is applied to the threads of a bolt and travels from the wrench, through the stem, to the threads so although 80 dry and 56 wet yield the same clamping force and tension on the bolt stem, the dry bolt stem will have to survive 80ft-lbs torsion during torquing but the lubricated bolt stem will see less torsion during installation than they would at 69ft-lbs dry.
Head bolts and studs (and most others) break during installation far more often than they do during operation. Manifold studs are the exception due to the extreme heat cycling they go through.

Personally I use Molly assembly lube on the factory original head bolts and torque them to dry spec, never had a head bolt break or head lift at up to 30psi so far (so far referring to boost pressure not time, I don't believe head bolts or head lift will be the limiting factor of the F2T).

Did you gap your rings for boost? This is very important, the thermal expansion on the rings under forced induction can case them to close, they lock up in the cylinder and break the pistons. Don't worry about extra blow by, rings need to sit at the top of the ring groove and require cylinder pressure to keep them seated there or gravity and friction will drag them down the groove, so they actually seat better with more gap, some pistons have holes in the crown that guide pressure to lower side of the 1st and second ring to keep them seated, these holes often clog with carbon build up, ring gap is better.
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