Cylinder head porting

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Mc Tool
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Cylinder head porting

Post by Mc Tool » Thu Feb 07, 2019 9:44 pm

I have a couple of spare pairs of rover heads, 1 rangies and 1 sd1, so I'm thinking about doing a bit of a port job myself , specially after after getting a quote of the port guru guy .
I have got me a set of uncle Rimmer's 35.5 mm ex and 41.4 mm intake valves and will get some of their guides as well ( the ones with the proper seals ). Bearing in mind the engine is going to be in a street car only, and will end up a 3.9, what does one have to do to improve things? A description or pix would be real helpful. Is it just the throat area or are the port runners in need of a bit of work too?
Thanks
Hamish


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stevieturbo
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Re: Cylinder head porting

Post by stevieturbo » Sat Feb 09, 2019 11:44 am

No doubt there are various books that could guide you.

But often for a novice, the less you do the more chance you have of not making a cock up lol.

Simple cleanup and smoothing around the throat area, improve the short side radius area. Do not damage the seats whatsoever, and ideally have someone very competent cut new valve seats.

Also some better valves will always be a good shout.
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Darkspeed
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Re: Cylinder head porting

Post by Darkspeed » Sat Feb 09, 2019 7:59 pm

Loads of posts and info on the subject will be found with a quick search as its a questions that has been asked many many times in the past.
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Mc Tool
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Re: Cylinder head porting

Post by Mc Tool » Sun Feb 10, 2019 7:48 am

Darkspeed wrote:
Sat Feb 09, 2019 7:59 pm
Loads of posts and info on the subject will be found with a quick search as its a questions that has been asked many many times in the past.
Yeah , you would think . Maybe I'm poop at searching but I got nowt,........hence the topic
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garrycol
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Re: Cylinder head porting

Post by garrycol » Sun Feb 10, 2019 8:45 am

The old port and polish will not do a lot for the RV8 - however just smoothing out the casting imperfections will improve thing greatly. As the RV8 inlet needs just a little roughness to get the best possible fuel/air mix, going to full hog of polishing etc will add little extra over a simple cleanup.

I got this advice from my 4.6 builder when I asked about this and he indicated that for a relatively standard RV8 just to remove the casting dags but not enlarge the ports and definitely no polish. When I got my heads back you could see the dags were gone with improved airflow but was not mirroe smooth.

Garry

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Re: Cylinder head porting

Post by Darkspeed » Sun Feb 10, 2019 5:17 pm

.
Last edited by Darkspeed on Tue Feb 12, 2019 8:05 pm, edited 3 times in total.
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ChrisJC
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Re: Cylinder head porting

Post by ChrisJC » Mon Feb 11, 2019 6:46 pm

There's some port sections partway down this page:
http://www.cowdery.org.uk/miscv8.php
You can see where material is best taken away!

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Mc Tool
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Re: Cylinder head porting

Post by Mc Tool » Tue Feb 12, 2019 8:25 am

Thanks for that Chris , helpfull in more than just the port pix . I have been having harrassments ( re runs of "some mother's do have them" on TV at the mo 😆 )with the bits between the end of the crank and the torque converter and the pix showed me that I have some bits of both gems and Thor set ups so no wonder the bits didn't all fit or make sense. I just need the correct bit that bolts to the crank with 6 bolts and to the flex and drive plates with 4 bolts ( I have all gems bits plus an extra Thor drive plate and the 4 bolt pattern on that is different ,couldn't figure where the firetruck that went 🙄😁 )anyhow , thanks man
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Re: Cylinder head porting

Post by ChrisJC » Wed Feb 20, 2019 9:10 pm

Good luck!

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Re: Cylinder head porting

Post by Mc Tool » Fri Feb 22, 2019 11:01 am

Just received a copy of " how to Port and flow test cylinder heads" by David Vizard, so make way for another instant expert :P
Garrycol, buddy " the old port and polish will not do a lot for the RV8 but removing casting imperfections will improve things greatly ".....I read it lots of times :roll: and ,well,doesn't really help....much :wink: ,and being as I'm going efi port wall texture ain't that important as the fuel doesn't get into the mix till after all that but it is relevant to all carbed engines. Seriously the book is a good read if your thinking of having a go yerself ,specially if you just want to tweak things a bit for a road car without blowing big gold on after market head castings.
Hamish
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Re: Cylinder head porting

Post by GDCobra » Fri Feb 22, 2019 7:28 pm

When I did mine I cut back the valve guides very close to the port, this probably opened the port more and gave less turbulence than anything else. I think.

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