ryanill
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| posted on 5/9/12 at 08:26 AM |
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Which cam should I pick ?
Hi all
I have a 2 liter pinto 205 block, lightened flywheel, cvk 38 mm bike carbs with megajolt
I am planning my winter upgrades now and have already started working on a spare head I have. The valve throats are 37mm standard so can open them up
fairly easily so no need for a big valve head. I'm having the head skimmed just not sure how much ? Any ideas out there guys ? 1 mm is
apparently conservative and you can get up to 1.5 mill skimmed.
The ports are being opened and ported as well as the combustion chambers tidied up and volumes matched.
I have checked all the valve stems and guides and are all in tolerance and valve seats are good also
I've been checking out burtons site and I'm planning on getting a cam kit it fit with the new head once it's all done.
I use the car on track days and for weekend touring so need a cam that will still be drivable at low end
At the moment the fr 32 and fr 33 cams seems to be the suggested ones cam any one guide me to witch one would be better?
The 32 power band is between 2500-7000 rpm
The 33 power band is between 3000-7500 rpm
A recent rolling road shows the current engin ( not with new head on) only produces power up to 5500 rpm but this may change after the above
improvements are made ??
Any help would be great
Cheers ryan
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mookaloid
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| posted on 5/9/12 at 09:01 AM |
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The key to it is how much head work you have had done. If it is only minimal then the FR33 won't release it's potential and the FR32 will
be a better way forward. If you have had the 'full works' on the head then the FR32 won't extract the best from the work that you
have done and the FR33 is the best choice.
It's difficult to tell from your description of the work but I think I would go for the FR33. I have used this one and I got a perfectly
acceptable tick over and good power up to and over 7000 rpm in bursts. I used the 205 block injection engine as a start - it has the best conrods and
and biggest valves as standard.
"That thing you're thinking - it wont be that."
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ryanill
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| posted on 5/9/12 at 10:04 AM |
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quote:
Originally posted by mookaloid
The key to it is how much head work you have had done. If it is only minimal then the FR33 won't release it's potential and the FR32 will
be a better way forward. If you have had the 'full works' on the head then the FR32 won't extract the best from the work that you
have done and the FR33 is the best choice.
It's difficult to tell from your description of the work but I think I would go for the FR33. I have used this one and I got a perfectly
acceptable tick over and good power up to and over 7000 rpm in bursts. I used the 205 block injection engine as a start - it has the best conrods and
and biggest valves as standard.
Ok sounds good. The head is a carb head and is off an spare engin I have for repairs.
The head porting will be done by myself. I'm and engineer by trade and have acces to all the tools ( apart from the miller to skim the head .
Btw did you skim the head you did ? If so how much by)
I'm not interested in generateint the absolute maximum out of this head. More than I am interested on how much power I can gain on a relatively
low budget ( just the cost of cam kit and skimming ) I've read many guides on porting and have ported a mini cylinder head in the past. All the
bumps and sharp edges will the removed and the inlets ports matched to the manifold. The carbs ave been spaced to line up with the ports so no bends
in the manifold allowing the inlets to be as short and straight as possible. I'm currently making this manifold. The inlets will be finished in
80 grit emery and the exhaust in 120.
Hope that has made it a bit more clear for you
Ryan
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snapper
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| posted on 5/9/12 at 10:20 AM |
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Just to add a bit...
The injection engine has better rods and inlet port short side turn
Ports do not need enlarging bigger inlets will help
Compression needs to be 10. To 1 or above but 10.5 is the cast piston limit
Rods are good to 7000 with the odd 7500
You need to measure piston to deck height & combustion chamber size, you can only work out compression accurately with these measurements.
There are head gaskets with different thickness which can be used to good effect
The Pinto likes compression
The pistons don't
The FR32 & 33 like to rev
The rods don't
Most Pinto cams have a little more lift and lots of duration, the Pinto likes lots of lift and less duration
The FR34 does well here but is all done by 6500
I had a 2.1 with standard injection head, FR32 and bike carbs it made 130bhp and 135ft/ibs with little tuning
IMHO FR32 for a better all round drive and would not only tick over well but pull hard low down and go on untill my nerves ( and ears) gave out.
I am in the process of building a 2.1 with Cossy rods & V6 pistons, (should have gone forged) I will use an RL31 cam and 10.7 to 1, when I tried
this combo the engine felt weaker than the FR32 to 3500 then took off
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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ryanill
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| posted on 5/9/12 at 10:38 AM |
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quote:
Originally posted by snapper
Just to add a bit...
The injection engine has better rods and inlet port short side turn
Ports do not need enlarging bigger inlets will help
Compression needs to be 10. To 1 or above but 10.5 is the cast piston limit
Rods are good to 7000 with the odd 7500
You need to measure piston to deck height & combustion chamber size, you can only work out compression accurately with these measurements.
There are head gaskets with different thickness which can be used to good effect
The Pinto likes compression
The pistons don't
The FR32 & 33 like to rev
The rods don't
Most Pinto cams have a little more lift and lots of duration, the Pinto likes lots of lift and less duration
The FR34 does well here but is all done by 6500
I had a 2.1 with standard injection head, FR32 and bike carbs it made 130bhp and 135ft/ibs with little tuning
IMHO FR32 for a better all round drive and would not only tick over well but pull hard low down and go on untill my nerves ( and ears) gave out.
I am in the process of building a 2.1 with Cossy rods & V6 pistons, (should have gone forged) I will use an RL31 cam and 10.7 to 1, when I tried
this combo the engine felt weaker than the FR32 to 3500 then took off
Ok well the engin Is compleat lay being striped this winter. I've never stiped and engine befor so want to do it to further my knowledge. I have
a very knowlageable friend to fall back on if I get stuck so all the compression can be figured out during the re build. And as the engine has never
been taken apart to my knolage the piston may well need changing any way.
Iv measured the smallest part if the inlets and the measure at 37 ( problem my bad explanation) so I'll leave them at that I think . As
I've said I would like to do this more as an experiment to see what results a relative newbie to this thing can achieve.
I'm not tied to ether a fr32/33 just seems to be what everyone's has suggested in my research
The engine currently has 113bhp so there is defiantly room for quite and improvement from what your saying
I'm going to stick with the carb head as once again it is at hand and ready to go
Thanks for the info
Ryan
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mookaloid
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| posted on 5/9/12 at 11:07 AM |
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If you have a little more cash to spend, a good thing to do is lighten the flywheel and have the whole bottom end dynamically balanced. This will make
it accelerate better (less inertia) and run smoother particularly at higher revs.
"That thing you're thinking - it wont be that."
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ryanill
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| posted on 5/9/12 at 11:10 AM |
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quote:
Originally posted by mookaloid
If you have a little more cash to spend, a good thing to do is lighten the flywheel and have the whole bottom end dynamically balanced. This will make
it accelerate better (less inertia) and run smoother particularly at higher revs.
Right oh
The fly wheel is already lightened and balanced
I asked the guy to make it as light as possible and still be safe. Ended up getting it to about 5 kg. how much dose the engine balancing generally
cost ?
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mcerd1
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| posted on 5/9/12 at 11:35 AM |
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I'm looking for a similar result with mine and I ended up picking a piper 285 cam (2200 -7000rpm, 270° duration, 11.81mm/0.465" lift)
I've got a 205 block rebored to 93mm (=2090cc), running with cossie rods & crank, forged pistons, steel flywheel all ballanced together
I've got ZX9R 'CVR' carbs, megajolt and dax's std. 4-1 exhaust.
I've left the head almost standard for now (just bronze guides, 3 angle valve seats and a bit of a skim) will do some porting later if I keep
the head (may go for a NA cossie instead)
the engine builder that did the maching for me skimmed the head to give me around 11.0 - 11.5 CR not sure what he took off, but he builds
pinto's all the time and knows what he's doing (I'll measure the combustion chambers to work it out exactly at some point)
my pistons are flush with the top of the block so there isn't much room for things to go worng 
I'll find out if its the right choice once I actully finish building the car....
[Edited on 6/9/2012 by mcerd1]
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mookaloid
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| posted on 5/9/12 at 11:36 AM |
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quote:
Originally posted by ryanill
quote:
Originally posted by mookaloid
If you have a little more cash to spend, a good thing to do is lighten the flywheel and have the whole bottom end dynamically balanced. This will make
it accelerate better (less inertia) and run smoother particularly at higher revs.
Right oh
The fly wheel is already lightened and balanced
I asked the guy to make it as light as possible and still be safe. Ended up getting it to about 5 kg. how much dose the engine balancing generally
cost ?
Not a huge amount - just ask your local machine shop for a price. Also if you are raising the CR then don't rely on a cheap head gasket - get a
good quality one - Cometic or similar preferably or at least a genuine Ford one.
"That thing you're thinking - it wont be that."
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ryanill
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| posted on 5/9/12 at 11:48 AM |
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I have all the gaskets ready for the rebuild but not a head gasket yet as I was aware there are different thickneses that with alter compression ratio
. So that with be sorted once it all goes back together . I'll defiantly look into balancing the bottom end yes
I'm sure the work will yield improvements in power, I'm just interested to see how much I will see and if you can get noticeable results
with small budget and a bit of work or if you want to see results do you have to pay for the head work to be done professionally .
Yes please post back once the car is finished will be interesting to compare results
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mcerd1
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| posted on 5/9/12 at 12:43 PM |
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quote:
Originally posted by ryanill
I'm sure the work will yield improvements in power, I'm just interested to see how much I will see and if you can get noticeable results
with small budget and a bit of work or if you want to see results do you have to pay for the head work to be done professionally
do you have a copy of one or both of these books ?
the second one is a bit out of date (it was writen before the EFI and cossie engines existed) but its still a really good read with loads of
background and advice on port shapes etc
you can find copies on ebay and the likes for less than a tenner 
also u2u me your e-mail and Ill send you a link to some stuff I've collected over the last few years
[Edited on 5/9/2012 by mcerd1]
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BaileyPerformance
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| posted on 5/9/12 at 01:10 PM |
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quote:
Originally posted by snapper
Just to add a bit...
The injection engine has better rods and inlet port short side turn
Ports do not need enlarging bigger inlets will help
Compression needs to be 10. To 1 or above but 10.5 is the cast piston limit
Rods are good to 7000 with the odd 7500
You need to measure piston to deck height & combustion chamber size, you can only work out compression accurately with these measurements.
There are head gaskets with different thickness which can be used to good effect
The Pinto likes compression
The pistons don't
The FR32 & 33 like to rev
The rods don't
Most Pinto cams have a little more lift and lots of duration, the Pinto likes lots of lift and less duration
The FR34 does well here but is all done by 6500
I had a 2.1 with standard injection head, FR32 and bike carbs it made 130bhp and 135ft/ibs with little tuning
IMHO FR32 for a better all round drive and would not only tick over well but pull hard low down and go on untill my nerves ( and ears) gave out.
I am in the process of building a 2.1 with Cossy rods & V6 pistons, (should have gone forged) I will use an RL31 cam and 10.7 to 1, when I tried
this combo the engine felt weaker than the FR32 to 3500 then took off
Why do you say 10.5/1 CR is the limit on the cast piston?
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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ryanill
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| posted on 5/9/12 at 02:56 PM |
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No I don't have a coppy of ether sadly but I do recal a friend mentioning a dave vizard book he had I'll have to ask him, if not fleabay
it will be for me
U2u sent . Thanks for offering the info i look forward to reading it.
Ryan
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snapper
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| posted on 5/9/12 at 05:39 PM |
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All the info i have ever read has said 10.5 max for Pinto cast pistons, i know some get away with 10.7 and even heard of 11 to 1 (Turbosports forum)
but they will "life" the pistons as Pinto pistons and rings are big and the ring lands are known to give way.
Personally I don't want to be the one that does the research.
Des Hammil says 10.5 to 1
Vizard says 10.5 to 1
Mike Egan quoting a lot of respected US builders says cast pistons are worthless
I could be running close to 8,000 with Cossy rods but will red line at 7500 due to the 2.8 V6 pistons.
If you have valid info on running over 10.5 on cast pistons i would be happy to add that to my bank of Pinto knowledge.
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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snapper
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| posted on 5/9/12 at 05:44 PM |
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ryanill,
The Des Hammil book is an easier read but if you do nothing else on your standardPinto head, smooth off the inlet port short side turn just below the
valve seat.
If you compare the standard Pinto and the Injection head its this area above all that makes the difference and gives the injection engine 5 to 10 bhp
more.
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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ryanill
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| posted on 5/9/12 at 05:56 PM |
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quote:
Originally posted by snapper
All the info i have ever read has said 10.5 max for Pinto cast pistons, i know some get away with 10.7 and even heard of 11 to 1 (Turbosports forum)
but they will "life" the pistons as Pinto pistons and rings are big and the ring lands are known to give way.
Personally I don't want to be the one that does the research.
Des Hammil says 10.5 to 1
Vizard says 10.5 to 1
Mike Egan quoting a lot of respected US builders says cast pistons are worthless
I could be running close to 8,000 with Cossy rods but will red line at 7500 due to the 2.8 V6 pistons.
If you have valid info on running over 10.5 on cast pistons i would be happy to add that to my bank of Pinto knowledge.
Ok fair point . I enjoy driving the car and doing track days but would not want to get it to such a level that it would keep wearing the internals
out.
So to clarify if I was to keep CR between 10:1 / 10.5:1 then the standard pistons and Rods will cope with it ?
At the moment the edis unit is a limited one of a fiesta and will not go past 6000 rpm so a non limited one will need to be found during the rebuild
what sorts of rpm is safe for the standard rods to take ?
Thanks to all you guys for the info by the way it's very much appreciated
Ryan
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ryanill
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| posted on 5/9/12 at 05:58 PM |
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quote:
Originally posted by snapper
ryanill,
The Des Hammil book is an easier read but if you do nothing else on your standardPinto head, smooth off the inlet port short side turn just below the
valve seat.
If you compare the standard Pinto and the Injection head its this area above all that makes the difference and gives the injection engine 5 to 10 bhp
more.
Yes I've stared the port work and have smoothed the edge so no sharp edges or bumps between the port and the seat . Is it just smoothing
I'm after or actually making the turn less severe ?
Ryan
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BaileyPerformance
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| posted on 5/9/12 at 06:02 PM |
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quote:
Originally posted by snapper
All the info i have ever read has said 10.5 max for Pinto cast pistons, i know some get away with 10.7 and even heard of 11 to 1 (Turbosports forum)
but they will "life" the pistons as Pinto pistons and rings are big and the ring lands are known to give way.
Personally I don't want to be the one that does the research.
Des Hammil says 10.5 to 1
Vizard says 10.5 to 1
Mike Egan quoting a lot of respected US builders says cast pistons are worthless
I could be running close to 8,000 with Cossy rods but will red line at 7500 due to the 2.8 V6 pistons.
If you have valid info on running over 10.5 on cast pistons i would be happy to add that to my bank of Pinto knowledge.
The limit of any piston is to do with the force applied to it or the amount of abuse it will take, for example running stock compression on a pinto
but with a well ported head, race cam ect will subject the piston to more force than a otherwise stock pinto with 11/1 CR. (as the tuned pinto will
make more power due to high cylinder pressure)
It is much more likely piston damage will result from poor engine setup than excessive CR, failed ring landings is caused 99% of the time by
detonation. Detonation is more likely to happen with high CR - so hence the "limit" was born!!
The fact is you can run high CR on almost any engine as long as it is set up correctly, the pinto is a good example as a stock engine will take 8PSI
of boost forever without a piston failure - this amount of boost produces far higher cylinder pressures that an NA engine will make using 11/1 CR.
As soon as you install forged pistons a poor tune can be tolerated as the pistons are much more robust - the key to a reliable pinto (or any other
engine) is to get it set up correctly. Then it has a fighting chance of staying in one piece regardless of CR.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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snapper
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| posted on 5/9/12 at 08:25 PM |
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Interesting points you make, I think the issues is getting it set up properly with pump gas and bike carbs, or any carb.
I would feel better if I had injection set up properly and have also heard of reduced advance to negate detonation, perhaps loosing some bhp.
I take your point though and seeing your forum name understand where you are coming from.
I have a conundrum, the head I have gives 11.2 to 1 on a 93mm bore, the cam needs at least 10.5 to 1 and I have been working on the premise that 10.5
is my max for the pistons, although when push comes to shove ill be closer to 10.7 but 11+ you sure??
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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BaileyPerformance
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| posted on 5/9/12 at 08:40 PM |
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quote:
Originally posted by snapper
Interesting points you make, I think the issues is getting it set up properly with pump gas and bike carbs, or any carb.
I would feel better if I had injection set up properly and have also heard of reduced advance to negate detonation, perhaps loosing some bhp.
I take your point though and seeing your forum name understand where you are coming from.
I have a conundrum, the head I have gives 11.2 to 1 on a 93mm bore, the cam needs at least 10.5 to 1 and I have been working on the premise that 10.5
is my max for the pistons, although when push comes to shove ill be closer to 10.7 but 11+ you sure??
You will be fine at 11/1 CR on 97/98 RON fuel - to be on the safe side (just encase you get some crap fuel) i would set the timing to 34deg TOTAL
(pinto's normally need 36 to make full power) assuming you are using a stock dizzy. The key to it is get the fuelling and timing right, luckily
the stock dizzy has a very soft advance curve, so setting the dizzy for a total of 34deg give you 12deg (ish) idle. Leave the vac advance
disconnected.
Big gains in drivablity and MPG can be found with mappable ignition such as megajolt - full EFI is the pukka way to go!
You MUST check the fuelling under load, get yourself a wideband AFR meter, you need 12.5AFR at full throttle. 13.5AFR is OK it light load but no
leaner.
After all this convention tuning you will be lucky to get over 160BHP. Consider leaving the engine stock and supercharging/turbocharging for 200BHP
plus with better MPG and drivablity. But this would involve full engine management to do it properly.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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snapper
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| posted on 6/9/12 at 06:12 AM |
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Don't want to nick the thread, but I'm running a well built head, large inlet standard exhaust, very nice porting, V6 pistons on Cosworth
rods, RL31 cam, bike carbs and Megajolt with MAP.
Engine has ARP everywhere, balanced inc light steel fly and clutch cover
Crank scraper, modified Cossy pickup with spraybar and high pressure pinto oil pump with cosworth oil pump top plate
Next purchase is an AFR meter and lambda
Thanks for the info I will build to the conservative 10.6/7 and limit the all in to 34 for starters
Always interesting technical conversations on this forum and I learn every day
Will keep you all posted on my build
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 6/9/12 at 07:42 AM |
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quote:
Originally posted by snapper
Engine has ARP everywhere, balanced inc light steel fly and clutch cover
Crank scraper, modified Cossy pickup with spraybar and high pressure pinto oil pump with cosworth oil pump top plate
the same as me 
that RL31 cam is a bit wilder than mine though, 304°/297° with .509"/.495" (2750-7500rpm) - that should be interesting to drive 
we'll need to have a rolling road day once were all up an running
[Edited on 6/9/2012 by mcerd1]
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cliftyhanger
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| posted on 6/9/12 at 08:15 AM |
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A couple of things that I have picked up over the years.
Firstly, it is VERY easy to over-cam an engine. The figures look good on paper, but remember what type of driving the car will be used for. The
compromises lower down the rev range can be hard to live with
Secondly, the dynamic CR is affected by the cam? so a wilder cam will require more CR. I expect many of teh compression issues are, as pinted out
earlier, to do with incorrect ignition and/or fuelling. I get really worried when people talk about a nicely built engine, then ask if the carbs
should just have the jets drilled out to XXXmm. That is no way to treat an engine, mapping needs to be far more accurate when pushing the engine.
All just observations (and some hard-won experience)
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BaileyPerformance
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| posted on 6/9/12 at 08:19 AM |
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quote:
Originally posted by snapper
Don't want to nick the thread, but I'm running a well built head, large inlet standard exhaust, very nice porting, V6 pistons on Cosworth
rods, RL31 cam, bike carbs and Megajolt with MAP.
Engine has ARP everywhere, balanced inc light steel fly and clutch cover
Crank scraper, modified Cossy pickup with spraybar and high pressure pinto oil pump with cosworth oil pump top plate
Next purchase is an AFR meter and lambda
Thanks for the info I will build to the conservative 10.6/7 and limit the all in to 34 for starters
Always interesting technical conversations on this forum and I learn every day
Will keep you all posted on my build
Sounds a good spec, one comment - you need to convert you megajolt to TPS from MAP - you will find TPS better for as the cam you have (and the bike
carbs) will not produce a very stable vac signal.
Dont be afraid to install a wild cam, for the weight of a the car (and the fact you have mappable ignition) you can get away with a hairy profile -
you need a good cam to get any power out of a pinto. You will be able to dial out the lumpyness of the cam with careful ignition mapping, abit awkward
to get the fuelling right with the bike carbs but not impossible. Dont do the usual trick of blocking the air correctors as this is a bad idea!
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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snapper
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| posted on 6/9/12 at 03:00 PM |
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I have a set of R1 carbs and a TPS megajolt ready to swap out the Mikunies and MAP jolt
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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