Peugeot 405 XU9J4 (MI16) head porting

Competition engines and ancillaries - general discussion
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zhenya_
Posts: 3
Joined: December 10th, 2009, 10:05 pm

Peugeot 405 XU9J4 (MI16) head porting

Post by zhenya_ »

Hello Guy and everyone.
It is very pleasent for me to write here.
This car works on bike carbs from Kawasaki Ninja zx9r.
Now I am trying to modificate the head of this engine.
I'd like to ask your opinion about my work.
Is it necessary to cut the seats into 3 angles? And what can it give?
Thanks,
Yours very sincerely,
Zhenya.
Attachments
ignition chamber<br />ignition chamber<br /> ignition chamber<br />ignition chamber
ignition chamber
ignition chamber
ignition chamber
ignition chamber
31.jpg (112.89 KiB) Viewed 8931 times
inlet port
inlet port
32.jpg (100.69 KiB) Viewed 8931 times
33.jpg
33.jpg (81.53 KiB) Viewed 8931 times
37.jpg
37.jpg (87.54 KiB) Viewed 8931 times
exhaust port
exhaust port
34.jpg (143.88 KiB) Viewed 8931 times
35.jpg
35.jpg (49.96 KiB) Viewed 8931 times
36.jpg
36.jpg (59.34 KiB) Viewed 8931 times
inlet and exhaust valves after polishing
inlet and exhaust valves after polishing
DSCF3608.jpg (132.05 KiB) Viewed 8931 times
Guy Croft
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Joined: June 18th, 2006, 9:31 am
Location: Bedford, UK
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Re: peugeot 405 XU9J4 (mi16) head porting

Post by Guy Croft »

I have done similar heads.

I recommend a very small diameter top cut (or grind) to true up the top section of the seat inserts first, this is important because if it's not concentric to the valve axis and properly perpendicular to it the contact face can be elliptical and you can lose the alpped seat altogether in places. I suggest 15 deg or better 20 deg. I know there isn't much room for the cutter, I think I used a Neway 20 deg set just slightly bigger than seat diameter. Always start on the seat insert which is in the worst condition as that will then set the valve tip height for all of them.

Other angles inlet: 45deg x 2mm x 75deg - fully blended into throat at the bottom.

Give the OE inlet valves (only) a 25 deg back grind leaving a contact face the same width as the seat insert one.

Exhaust: top cut as inlet the 45 x 2mm x 70 deg again fully blended into throat.

I suggest you do the inlet valve back-grind and lap in/ex valves before doing the final 75 & 70 deg throat grind as you can then grind right up to the contact face on the inlet (which, if you've done the back grind right will be 2mm wide); on the ex side you can use the 70 throat grind to reduce the width of the ex contact face down to 1.5-1.75mm


Hope this helps some,

G

Remember that seat mods drop the valve deeper into the head - be careful that you can do the valve clearances. Of course you can grind the valve tips to reduce the tip height.
Attachments
showing reground inlet 45 contact face and 75 deg throat grind
showing reground inlet 45 contact face and 75 deg throat grind
misc 010.jpg (114.05 KiB) Viewed 8915 times
blending the 75 throat into the port. The angle that joins the 45 and 75 must be left sharp. Poor casting quality has left a savage undercut below some of the seats - there's NOTHING you can do about this so don't try.
blending the 75 throat into the port. The angle that joins the 45 and 75 must be left sharp. Poor casting quality has left a savage undercut below some of the seats - there's NOTHING you can do about this so don't try.
x 004.jpg (118.94 KiB) Viewed 8915 times
fully dressed chamber and finished angles ready for lapping. Best to do the chamber first otherwise you have to fit dummy valves to protect your precious seats.
fully dressed chamber and finished angles ready for lapping. Best to do the chamber first otherwise you have to fit dummy valves to protect your precious seats.
x 028.jpg (119.39 KiB) Viewed 8915 times
Inlet valve back-grind
Inlet valve back-grind
x 032.jpg (120.3 KiB) Viewed 8915 times
record the valve tip height data before and after seat work  - this is from an S16 I did
record the valve tip height data before and after seat work - this is from an S16 I did
Peugeot 306 S16 05.096 VSH data.jpg (104.57 KiB) Viewed 8915 times
zhenya_
Posts: 3
Joined: December 10th, 2009, 10:05 pm

Re: peugeot 405 XU9J4 (mi16) head porting

Post by zhenya_ »

Thanks Guy for your advice. I try to do as you said.
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