flak monkey
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| posted on 14/5/07 at 05:24 PM |
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Unleaded pinto heads and bigger valves
I have an unleaded pinto head as a base for modification and am wondering how the seats are hardened. I.e. if i have gp1 valves fitted will I need to
have new hardened seats fitted too?
This isnt happening until the winter, but I am trying to find out all the relevant info now so i can budget 
Cheers,
David
Sera
http://www.motosera.com
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mark chandler
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| posted on 14/5/07 at 06:13 PM |
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They cut em out and drop in inserts, just make sure the inserts have a large throat area.
rgds Mark
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flak monkey
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| posted on 14/5/07 at 06:16 PM |
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I know how they fit hardened seats to normal leaded heads, but I was wondering if my unleaded head (not modified to be unleaded, its an
injection head) will need new hardened seats putting in if I have GP1 valves put in?
Sera
http://www.motosera.com
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TangoMan
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| posted on 14/5/07 at 07:15 PM |
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It really depends on how big seat inserts are. It will have had steel inserts during production which will be slightly bigger than you valves so may
cope with larger valves.
I would suggest measuring the seats and then deciding how big your valves can go without requiring new inserts. It may be that you are stuck without
new inserts but hope not as it could get expensive.
Summer's here!!!!
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snapper
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| posted on 14/5/07 at 08:05 PM |
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Injection head only had or needed hardened exhaust seats and there is plenty of meat for the biggest valve seats to be cut. Generally you can get away
with standard exhaust valves and very little modification of the port throats.
If you really must have the big numbers then 38mm valves with the throats opened to 34.5mm and blended in for the exhaust and 45.4mm inlet with the
throats opened to 39mm.
Visards book is full of info but really for the full race engine, how to power tune the Ford SOHC by Des Hammill is a more street orientated book.
Its worth thinking about the cam you want to use, and whilst i can't find my Burton catalogue at the moment i am pretty sure that after you have
fully flowed your head you will get no more flow once valve lift at the seat exceeds 1/4 of the valve diameter.
[Edited on 14/5/07 by snapper]
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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flak monkey
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| posted on 14/5/07 at 08:25 PM |
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Thanks Snapper, got the books with the info in, just couldnt find any reference to the hardened seats
Itll be GP1 valves so 38.1mm ex and 44.5mm in with the ports opened out as described in the Des Hamill book. Probably fit a Kent FR33 or Piper 285
(whatevers cheapest at the time!). Full balance on the bottom end, and a fat pair of 45s should see a nice amount of power, hopefully! 
Thanks again, looks like I might just get away with it.
David
Sera
http://www.motosera.com
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david walker
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| posted on 14/5/07 at 08:26 PM |
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The answer to your question monkey boy is YES, they can be machined to accept the big valves.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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flak monkey
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| posted on 14/5/07 at 08:41 PM |
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quote:
Originally posted by david walker
The answer to your question monkey boy is YES, they can be machined to accept the big valves.
Thanks very much David, as far as I am concerned your word is gold, so thanks a lot!
Who you callin' boi?
David
Sera
http://www.motosera.com
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PeterW
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| posted on 14/5/07 at 10:03 PM |
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No point in going bigger valves on the pinto heads as they are already over sized as it is.
Increasing flow is the key, and getting the angles right. The top of the inlet tract is not steep enough, it needs opening up towards the rocker gear,
get bronze valve guides put in the head, slim down the tops of the valves and bobs your grandmas son.
Also, roller rockers are a good idea (see Holbay for ideas) and watch the cam overlap and lift cos it can start to become self defeating.
Tighe Cams in Australia could sort you a decent cam for Burton money, and done to your spec. Guy at
work used to run a reliable 175BHP on a 2l pinto....
Cheers
Pete
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TangoMan
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| posted on 14/5/07 at 10:15 PM |
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quote:
Originally posted by PeterW
No point in going bigger valves on the pinto heads as they are already over sized as it is.
Increasing flow is the key, and getting the angles right. The top of the inlet tract is not steep enough, it needs opening up towards the rocker gear,
get bronze valve guides put in the head, slim down the tops of the valves and bobs your grandmas son.
Cheers
Pete
ERM..... I think larger valves will be a benefit as you can't get too much valve area. The ports are not ideal but are much better on the
injection head that Flak has.
In any head, normally aspirated, valve area will always be the bottleneck as the valve spends most of it's time opening and closing so is rarely
full open. Port shape/size and transition into the throats all helps give a clear run to the valve but the valve area is key. Slimmed down RimFlo type
inlets will be a benefit but don't go too thin with the exhausts as they need to handle a good amount of heat.
Don't forget to unshroud the valves by opening out the sides of the chambers as you will lose all the benefit of those larger valves.
Summer's here!!!!
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flak monkey
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| posted on 15/5/07 at 06:38 AM |
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I did a load of head work on the one i have at the moment, but nothing too substantial. All that got done was the ports and valve throats opened out
slighty, but nowhere near the full amount. I am planning on opening the ports to the recommended sizes in the Hamill book (the inlet port itself
doesnt need much doing to it, its mainly the throat and flattening off the turn. The exhaust side is where most of the work is required.) Including
removing the old valve guides which protrude into the ports, and having them all replaced with bronze guides when I get the seats re-cut.
I am after a copy of the Vizard book if anyone has one that they no longer require? It seems to now be out of print. 
Thanks for the input gents.
David
Sera
http://www.motosera.com
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david walker
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| posted on 15/5/07 at 11:22 AM |
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Be carefull, money is usually hard earned and don't forget most of the people on here (but by no means all) are only bar room/internet
experts.
Race valves benefit not only through shape and size but also weight. Compare them when you buy your new ones.
175bhp today from a 2L Pinto is average. F2 Stockcar boys get 160 on a std engine, blueprinted and a cam.
Up to you but forget roller rockers - they offer little gain on a Pinto and are horrendous things to fit and adjust - particularly the Holbay ones.
And yes, I've fitted them in the past.
Best cam for the Pinto is (IMO) the Piper A8, nothing comes near it.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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flak monkey
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| posted on 15/5/07 at 12:27 PM |
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Thanks David, I had no intention of fitting roller rockers etc as they are way out of my price range!
Would the A8 need any extra machining on the head (valve spring seats etc?) as I see its got 0.5" lift? I cannot remember what the limit is.
Thanks,
David
Sera
http://www.motosera.com
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iank
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| posted on 15/5/07 at 12:33 PM |
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Would it not be cheaper (at the end of the day) to get the power you want by fitting a zetec? Post SVA obviously.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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flak monkey
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| posted on 15/5/07 at 03:17 PM |
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If you factor in the cost of the zetec (say £150), megasquirt (same again), ITBs (because I am fussy), a pair of cams (£300+) complete new exhaust
(£400), new bonnet (£100) and the list goes on to get close to the power I am expecting from the pinto.
The pinto will cost me however much getting the valve seats cut will cost, plus the cost of the cam kit and valves (so say £500 in all) - the rest of
the work I will do myself. Plus I also have a set of 40dcoes for sale, a complete refurbed mild tune head etc which will recoup much of the
expense.
The pinto will cost me very little to upgrade, an engine swap to get close to the power will cost a substantial amount.
If I had the money I would drop in a duratec, but thats several grand over my budget.
Each to their own.
Sera
http://www.motosera.com
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david walker
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| posted on 15/5/07 at 04:06 PM |
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In my opinion, for a sports car application the Pinto is streets better than the Zetec. The Zetec's expensive to tune and in std form a bit
lame. That said it's a modern unit, smooth usually trouble free, but at the end of the day its a saloon car engine.
The Monkey's also right about the Duratec. People talk blandly about fitting one and seeing an instant 200hp. It doesn't just happen it
costs a substantial amount of cash to get there (with reliability). Prices will come down, and already we see them as taking over from the XE - but
not for the budget racer yet!
Too often the Pinto is put down on here, usually by people who have no first hand experience of them. Still an excellent unit, easy to mod, not as
heavy as everyone says and well within the scope of the diy mechanic.
How many "contributors" and "advisors" on this forum have actually driven a 180hp se7en? - I know I'm getting old but
they can be frightening!
The A8 cam requires no seat machining but you will need the matching Piper springs. I've fitted a good many and always buy their camkit.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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flak monkey
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| posted on 15/5/07 at 04:09 PM |
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Thanks David, your advice has, as always, been invaluable.
Now I just need to find a piper dealer
[Edited on 15/5/07 by flak monkey]
Sera
http://www.motosera.com
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