po79
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| posted on 2/12/10 at 03:15 PM |
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Pinto big valve heads.
Hi all,
I'm thinking of converting my 2.0 pinto engine to 2.1 and need some pointers please.
Its a 205 block so suitable for this mod but the first thing I want to do is get the cylinder head modded with big valves decent cam and some porting
and polishing.
This isn't cheap so I need to find someone who can undertake the work at reasonable cost.
Once I get the head done I'll run it on the standard bottom end for a while and see if I am happy with new performance but if I still need more
power I'll look at getting the engine bored, I have all ready decided that if I do this I'll use oversized pinto pistons so there
shouldn't be any need to deck the block and these seem to be the cheapest option and made for the job.
So like I say really need to be pointed in the direction of someone to do the head work that don't charge the earth.
Cheers,
Po.
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mookaloid
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| posted on 2/12/10 at 03:43 PM |
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in terms of BHP per £ spent the head work is far more cost effective.
You can spend loads on a capacity increase but the BHP return is very poor by comparison to the returns you get from upgrading
head/valves/cam/carbs/exhaust.
"That thing you're thinking - it wont be that."
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mcerd1
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| posted on 2/12/10 at 04:00 PM |
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yes a 205 block is suitable, you can bore it to 93mm without any issues (93mm = 2090cc)
the you get +2.25mm (~93mm bore) but I think these are the shorter 2.8 V6 ones (please check this)
you can use cossie conrods to make up the difference (they are 0.060" longer) but then you need to have the pistons modified for the floating
pins & circlips
of course the cossie rods are alot stronger than std. ones (the rods are one of the main pinto weak points if you want to rev it passed 7500rpm) but
most people don't actually need the extra strength anyway
in the end you might find that the 2.1 pinto doesn't make that much more power than the 2.0, but it will have a bit more torque...
you'll get more power from the head so thats the first thing to look at,
you don't need to go for bigger valves unless you want the maximum power possible - there are significant gains to be had just porting the head
with std. valves
and a nice lumpy cam will work wonders if you've only got a std. one just now
I know who I'd get to do the work up in this part of the world, but its a bit far away from you 
what spec have you got just now ? (carbs, cam, exhaust, ignition....)
and whats you upgrades budget ?
Its easy to get carried away with these little upgrades - I've spent more than I want to think about on the my pinto and thats before the cars
ever been on the road  (cossie crank & rods, forged pistons, steel flywheel,....... I'm adicted to shinny bits  )
[Edited on 2/12/2010 by mcerd1]
[Edited on 2/12/2010 by mcerd1]
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Confused but excited.
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| posted on 2/12/10 at 04:04 PM |
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Lyons Bros in Swansea did my X-Flow head for less than half what Burton would have charged (They quoted £475 for the same job).
Chemical clean, head ground true on all mating surfaces, new hardened larger valve seats, new big valves, springs and bronze guides. Inlet ports also
opened up to GT size. £220 all in.
Might be worth giving them a ring.
From what I have read on here, would it not be more economical to swap out for a Zetec/Duratec if you want more power ?
[Edited on 2/12/10 by Confused but excited.]
Tell them about the bent treacle edges!
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b16mts
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| posted on 2/12/10 at 04:11 PM |
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I swapped heads on my 205 block this year. the only difference was the new head has a kent fr33 cam. with bike carbs etc. it ended up with 119bhp at
the wheels. wonder how much difference porting etc would do for me. the cam has completely changed the car.
martin
PS. I got this complete head for £83 off ebay with about 1000 miles since full rebuild with new valves followers etc.
[Edited on 2/12/10 by b16mts]
who says you can't drive a kit car when you're 6'5"?
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po79
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| posted on 2/12/10 at 05:07 PM |
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Hi all,
Like I said I'm not over confident that I will need the 2.1 rebore so all I'm planning for now is the head work, not looking for mega
power just better power!
Thats why I would only use off the self oversize pinto pistons as these are a straight fit with no need to deck the block or mess with the con rods
just rebore fit the new pistons and off you go!
The polishing and porting I will probably have a go at myself. Not sure what cam to go for as I have never got involved with these much before.
So does fitting larger valves not do much then?
As for budget as cheap as I can get stuff for really, I've had stacks of work cancelled latey some weeks only working a couple days and none in
others!
Thanks for the feedback so far, maybe I'll put a wanted ad up for a head and see what happens.
Po.
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jacko
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| posted on 2/12/10 at 05:22 PM |
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The biggest increase in bhp was when i fitted zx9r bike carbs
i also had it
reboard 60th
light flywheel
the head was planed 1mm and polished / ported
it has a piper 285 ultimate road cam
On Bogg Brothers rolling road it made 140 at the rear wheels
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snapper
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| posted on 2/12/10 at 06:00 PM |
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Get yourself an injection head for starters, better inlet shortside turn.
Don't polish the ports, use bigger inlet valves with the port throat opened out, 3 angle valve seats and 30deg cut back on the valve.
Skim just enough to make it flat as you will need to match the compression to the bottom end.
Even with +2.25 pistons these will be below the deck.
Cast pistons have a 10.5 to 1 max compression limit, this limits the cam to no more than 300degs duration or you loose low down flexibility.
Adjusa head gasket crushes to 1mm adding 0.5 compression ratio.
If you fit bigger valves, relive the edges of the combustion chamber as Visard or the How to power tune pinto book, this opens up the chambers then
skim head to restore compression.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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mcerd1
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| posted on 2/12/10 at 09:48 PM |
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quote:
Originally posted by po79
So does fitting larger valves not do much then?
they do plenty at the top end, but if your just doing a fast road tune and wanting to keep costs down...
what carbs/ exhaust/ ignition do you have just now ?
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po79
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| posted on 3/12/10 at 03:45 PM |
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Hello,
Exhaust is 4-2-1 mild steel manifold and down pipe (for now) and performance stainless system. Carbs will be ZX7-R when I finish them and the ignition
is standard but I'm still looking for an upgrade.
So leaving the valves will save me a big chunk and sound like it would only be needed if I looked at serious power and tuning.
Good news there then!
Cheers,
Po.
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mcerd1
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| posted on 3/12/10 at 04:01 PM |
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its all about matching up the right bits - not much point in fitting some wild head with massive valves if your only going to feed it for little
carbs.... 
don't know what choke size the ZX7R has, but I'd guess your in the same ball park as twin 40 webber's - so probably not worth going
for anything too wild
that said the stock car boys arn't allowed bigger valves and they still get silly power
ignition wise have you thought about megajolt ?
it should cost less than most modified dizzys and you can re-tune it yourself anytime you make a change
if your carbs have a TPS sensor you can connect it up to get a 3D map for better fuel econommy & power delivery (same job the vac. advance does on
the std. dizzy, which they take off on most tunned dizzys... )
[Edited on 3/12/2010 by mcerd1]
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po79
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| posted on 3/12/10 at 04:28 PM |
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All this is pretty new to me. All the cars I've ever had I have left standard so this will be a learning curve for me.
I just don't want to get out of my depth to quickly!
What are your thoughts on a Kent Fr22 cam? There is one on that auction website and also a gas flowed head with standard valves I was thinking of
bidding on.
I think your right about the bike carbs being about the same as twin 40's from what I have read about them, I have two of them and they both
have the sensors on them.
Po.
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