3vzfe and 1mzfe cylinderheads how to modify them.

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[url=https://imoc.co.uk/app.php/kb/viewarticle?a=155&sid=dd37aab9517bf1f3608908698aebfc3f]Knowledge Base - 3vzfe and 1mzfe cylinderheads how to modify them.[/url]

Most of the 3vzfe info here is applicable to the 1mzfe, note that the exhaust ports on the 1mzfe are more like the 1uzfe and still respond similarly to the 3vzfe when being modified.

I have tried to ensure as much relevant detail as possible is included but errors and omissions
can unfortunately creep in, so if in doubt at any point, re-read and if still unsure, ask!
Now thats out of the way, lets see what tools are needed.
Youll need either a high speed air or electric die grinder (electric is best) although an electric drill can be used and at a pinch a dremel type tool- however theyre generally unsuitable because the tools are smaller and remove less material.
Better to use that for detailing/cleaning up jobs later on.
A supply of 80 grit abrasive cloth on a roll.
A carbide “Oval” Burr.
Some wd40.
Paper towels ( lots of them)
A vacuum cleaner would be useful also.
A plastic storage box for washing purposes.
A valve spring compressor to remove the valves.
A piece of ¼ inch rod around 6 inches long with a slot hacksawed into one end.
A dust mask and some eye protection.
At this point ill assume you have enough knowledge to have removed the heads off the engine,removed and ordered the valves correctly.
Read the engine manual if youre unsure how to do that and get familiar first!
Clean the head in the plastic box with Jizer or some other engine cleaner that has a corrosion inhibiter in it otherwise the guides and seats will rust.
Once done with the majority of cleaning, dry the head and blow it off with compressed air if available and use your can of WD40 to coat the guides both inside and out and the seats to further protect them along with the cam cap retaining studs.
Unless you want your hands torn to shreds, its a good idea to deburr all sharp external edges with a carbide cutter or sanding roll, so do that next and save your fingers.
Deburr all the coolant transfer passages also, build ups of corrosion here can impede cooling.


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Ok, if you look down the intake ports youll see all manner of interesting stuff.
Casting marks, valve guides, the bosses and ridges left by machining ops at the factory etc.
The first thing to note is this: Be guided by the fact that youre not going to be making these ports monstrously bigger so resist vigorously the urge to go bananas with your carbide cutter!
If youve got a pile of chippings as deep as your armpits when youre finished, then you may have gone a little too far.....
This first photo shows a view down the port as itd normally appear minus the valves of course.

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Things to note.
Rough surface texture, guide bosses and guides, fairly wide splitter, machining ridges left by
the factory.

The next shot shows the chamber, the seat and bowl areas.

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Note the thin light coloured ring of material around the base of the seat insert.
Thats been left by the machining ops.
At the top of the port theres a sharp edge.
The clean ring around the valve seat is where i already cleared the usual ridge left by the factory.

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So where to start?
First attach a vacuum cleaner to the port and use it to keep the dust and chippings down.
If you cant use a vacuum cleaner, then wear a dust mask, aluminium dusts not supposedly good for your memory ( alzheimers) so protect yourself just in case.
I usually start at the port mouth and smooth the surface, just removing casting lines, flash etc.
Its important to run the tool fast enough to cut the port material but not press on it as itll clog
up rapidly and end up slowing you right down.
Just let the tool cut steadily and keep it moving.
Youll develop a natural sweeping motion as you progress.


Once youve done all the port floors or roofs, turn over the head and do the opposite sides, just removing marks and ridges.
By now youll start wondering if youve done the right thing and worrying how long itll take.
Its not a fast job and thats where the patience part comes in.
This is how itll look as you proceed.

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Ok so youve removed the casting marks and generally smoothed the surface.
The valve guide bosses on these can give you a couple of cfm for just a few minutes work, so its worth spending that time to reduce their size.
Just remove the material at either side and lower the height of the surface blending it in to meet the guide, making it more aerodynamic.
Try to get both sides of the boss symmetrical and mirroring its neighbours but dont worry too much about surface condition at this point, minor changes wont make any noticeable differences and in any case the surface will be addressed lastly after everything else is done.
Use the photos as a guide for what to aim for.
Assuming youve got all the guide bosses reduced in height and nicely shaped and the ports lead in sections all roughed out, we can turn the head over and start from the other side.
Position the head so the manifold face of the intake port faces upwards.
At the bowl area (arrowed) use the oval burr to remove the edges of the alloy that overlap into the airstream, blending the material so it ends up level with the valve seat insert.
Youll notice at the sides of the port a deep ridge that alternates on each set of ports, caused by the factory machining.
Feather these into the seat insert and port as youve done with the rest of the bowl.
Now turn the head over ( prop it up on a length of timber if needs be) so the intake manifold face is pointing downwards.
The short side radius turn is next up.This is opposite the bowl that youve just blended in.
If you look at it, youll notice an apparent lip, almost an overhang where the factory tooling has cut into the port to produce the seating area for the insert.
This sharp lip is detrimental ( very) to getting air into the cylinder because air dosent like to take sharp turns and when its moving at close to supersonic speeds as in a port it really
dosent like to change direction.
The air coming off that lip creates vortexes and back eddys that make the stream turbulent which stops air further back up the intake from going where we want it.
When reshaping this turn we want to be making it aerodynamic, which is what the profile will be when we’ve finished on it.
Ive already done the hard work for you here and made a copy of the profile in 3D and scanned this radius gauge thatll allow the port to flow close on 245cfm as opposed to just 204 if that radius is wrong.
You need to copy the shape as closely as you can and use it to check the shape of the turn as
you go.

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Typical flow result from simply rounding the edge.

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Result of modifying to the shape shown with the radius gauge.

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This is one of the hardest parts of the job and itll take quite some time to get it just right but the payoff is way better flow with the valves in than youd get just by rounding that edge off.
Once youve carefully shaped the short side radius, you need to apply some efforts to the sides of the port walls where the SSR meets the vertical parts.
If you position the head on its end and look back up the intake from the valves, youll notice a “hump” type shape as the port wall makes the turn.
Its present on both outer and inner walls ( splitter side).
Youll need to be careful how you approach this bit of the job, what youre doing is making room for the air as it slows and goes around the SSR and blending the sides and SSR together, but not cutting into the already modified SSR.
In my case I transfer the head back and forth to the bench, test it, modify the area then retest to check the changes, takes ages.
Youre not going to be able to do that, so just aim to smooth and flatten that hump on both sides of the port, blending it in to the SSR at the apexes.
A gentle touch with a finger can usually detect what the eye dosent, so use that as a guide and stop when it feels smooth and flat.
Now youve done all these, turn your attention to the port divider/splitter.
The basic idea here is to slim the bluff nose of it down, reducing its width at the leading edge and smoothing the surfaces as it proceeds further into the port.
No need to knife edge sharpen it, just apply a small radius so its not dead sharp and dont work soley on one side, itll end up biasing the flow one way or the other which affects overall flow, again patience and care will see you right.
Use a pair of dividers to keep it central in the port by comparison.

Incidentally, i discovered that a small pea sized piece of plasticine applied to the bottom of the splitter had the effect of altering the air flow characteristics so a totally unmodified port would flow something like 225cfm, although post modification the phenomenon is absent.

Once youve completed all the major works in the ports you can start to apply a surface finish.
I use 80 grit sanding drums and 80 grit emery wrapped around a rod to further flatten and smooth the surfaces and impart a nice flow friendly surface.
Its best to run this at a moderate speed as too fast will just make it uncontrollable and the media wears faster.
You can use wd40 to help but I dont find it always necessary except in the chambers.
Start at the port mouth and work around the periphery, youll feel and see the effects of it almost immediately, continue that method all the way .
To get that cross hatch effect, make a copy of the split fork deburrer tool shown in the photo,stroke the tool back and forth covering the entire port, but be sure to not dwell in one area, keep it moving until youre satsified with the results and you
have a uniform finish.

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Basic shape differences between the modified on the left and the as factory cast ports on the right, notice the nice smooth radius.

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In the chamber, use the sanding drum to carefully dress the surface and remove the myriad of pits and marks in the alloy.
Youre just aiming to remove sharp edges and blending surfaces.
Try to form smooth contours where the alloy runs down to the seats.
There are lots of edges in this part of the chamber and I use a homebrewed cutter to remove them evenly, but its possible to use old valves with the outer diameter reduced and the head ground with a bevel to protect the seats while youre working in the chamber with a sanding
drum, something i also use.
Aim for a 120 grit finish in the chamber and use a small piece of red scotchbrite to polish the chamber off with.
You can go smoother but it takes a lot of effort and time.
Aim to get the ports and chambers as shown in the photos.

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The exhaust ports are far simpler to work on believe it or not.
They too suffer from all the intakes casting flaws and can be improved quite markedly.
The 3vz fe has an odd head design especially on the exhaust ports because theyre not identical across all three of them.
Two are of a “dog leg” design whereby one side of the port is a straight shot out with the
other runner coming in at around 40 ish degrees and merging.
This creates turbulence and a loss.
All we can really do here is improve it so it flows better.
The “odd” port out on the end of the head is more of a siamesed design with almost equal length runners and this definitely flows better to the tune of around 10cfm over the other
exhaust ports.
That kind of leads to a bit of a quandry.
Improve it or not?
Well yes, but bear in mind itll easily outflow the other exhausts if you apply the same measures to it as all the others.
I tend to develop the dog legged ports to flow equally and as highly as I can bearing in the mind the exhaust to intake ratio and try to get them at 80% and then do that “straight shot” port last, balancing the airflow to match the others.
All youll be able to do, is make them resemble each other as closely as possible and leave it at that.
I have it on great authority that balancing the exhaust flows isnt as critical so im happy to bow to much greater knowledge on that score.
Ok, proceed with the exhaust ports as per the intakes, removing casting lines and imperfections at the port exit (at the face and working inwards).
Theyre awkward to do due to their shape, but stick with it and youll get there.
The guide bosses are a fair size on these.
Reduce them as per the intakes, mostly on the widths and the “ramp” at the front of them leading to the guide, smoothing and blending them in.
Once youre happy with these, turn the head over and examine the bowl area ( under the valve
head).
Youll notice some material just below the seat which needs smoothing and a rather large overhang.
I try to blend the overhang into the seat insert/ port but its pretty much impossible to remove
it entirely as youd have to burrow into the material far deeper than really is good and its
purely an aesthetic operation to remove it which you wont see when its all together anyway.
In this case, just smooth it as best as possible.
The sides of the ports at the divider have a similar “hump” to the intakes, so again its a case of basically flattening them and blending in to the rest of the port.
The exhaust also has an SSR which heavily influences how well the port can flow.
A finger prodded into the port will expose a sharp edge which creates restriction and turbulence just as on the intakes.

Exhaust port mould, notice the sharp edge at the left, (short side radius is non existent).

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Using the template for exhaust ports, develop a nice radius as shown here which will flow a significant amount more than stock.

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Use the tool template shown to develop a highly flowing port.
Once youve addressed that, apply a similar finish to the exhaust port surfaces as the intakes using the methods youll now have developed.
You can finish these to 120 grit as itll help to reduce carbon buildup than a rougher surface which can alter the flow of the ports over time.
If youve done a good job, you should have ports that are closely matched for both flow and give a good improvement.

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Areas requiring attention.

Heres a 3vzfe head in section view, the most important areas to modify are between the red lines.
This ports already had the sharp edges removed and flows better than stock but its nowhere near as good as it can be.

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Added extra info.

Refer to the two photos of the sectioned lower intake manifold.
Note the "bump" in the roof just prior to the injector.
This creates a loss and should be reduced as much as possible to match the intake port size.
Care needs to be taken to remove only enough material so as not to break into the the air assist channel that feeds the injectors.
Remove material also from the sides and upper corners of the runner using a pair of dividers calibrated to the port size as a guide, leave the floor of the runner alone, removal of material here has no effect.

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Looking down the lower intake, notice the top of the runner is closed off by that "hump" in the roof.

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Note: the radius gauge templates should display at full size (119mm long on the longest run) simply trace it to paper or plastic and transfer to steel or alloy sheet.