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Mild Pinto rpm @ max power?

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Wozzah
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Re:Mild Pinto rpm @ max power? 2013/02/25 17:17:46 (permalink)
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Noono

Thanks James & spigot,
The full story is:

Club rego, so will be driven in city occasionally as well as club level motorsport.
Twin 40mm dcoe webers, 4-2-1 headers, 2.25" exhaust.
Pinto block bored 1mm o/s, decked 0.25mm, standard crank & rods, Hepolite flat top cast pistons which come to 0.3mm below block deck.
Current head decked 2.3mm, Grp1 valves, basic Vizard porting, Waggot cam In 43/80, Ex 80/43, duration 303, lsa 108.5, lift 11.2mm.
The theoretical c/r is 10.8 : 1 which I've read is a little high for cast pistons.

It's a dog at low rpm, which I think is due to the large duration & valve overlap.
I have picked up a good untouched head, so I thought would get built with a different camshaft & about 10:1 c/r.
With the current block/piston setup, I would only need to shave the head 1mm max.

I liked the look of the Kent FR30 because of 260 duration & 12mm lift. I guess it's great around town, but may have peak power
too low for motorsport.
James, the Piper 270 looks like it could be a good option. Also the Kent website figures for the FR32 are
In 34/71, Ex 68/32, Duration 285/280, Lift 11.6/11.2mm, Lsa 108.
Spigot, the websites don't give 0.050" durations, but I guess only an email away. What does std hc bottom end mean?

Cheers, Gregg


 
Gregg, the cam specs I suggested earlier should be about on the money for that rpm range.
 
Cheers,
Woz
 

Mk1 RS2000 replica (IP hillclimb car) fitted with Ford Laser 1.8 DOHC (BP) Cossy cams, Webers, 230hp
EB XR8 5sp, heads, cam, extractors.
http://www.facebook.com/p...rmance/135194779879292
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spigot
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Re:Mild Pinto rpm @ max power? 2013/02/25 17:27:04 (permalink)
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What was the timing set at?
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Noono
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Re:Mild Pinto rpm @ max power? 2013/02/25 21:56:16 (permalink)
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Thanks Wozzah.
 
I found the 0.050" timings for the Waggott - In 2/42, Ex 42/2, Duration 224
Is that similar to problem you mentioned with Crow - large advertised duration for small .050" duration ?
 
Spigot - full lift of inlet valve set at 108 deg ATDC,
Ignition timing 14 deg BTDC @ 1000rpm, Max 35 deg BTDC achieved at 3,500rpm
 
Cheers, Gregg
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spigot
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Re:Mild Pinto rpm @ max power? 2013/02/25 22:47:42 (permalink)
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I have had a very bad experience with waggot.

Have you done a compression test?

Have you verified the actual cam position?

Have you tried loosening up the clearance on the lash, this will simulate a smaller cam?
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Wozzah
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Re:Mild Pinto rpm @ max power? 2013/02/26 12:46:38 (permalink)
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Noono

Thanks Wozzah.

I found the 0.050" timings for the Waggott - In 2/42, Ex 42/2, Duration 224
Is that similar to problem you mentioned with Crow - large advertised duration for small .050" duration ?

Spigot - full lift of inlet valve set at 108 deg ATDC,
Ignition timing 14 deg BTDC @ 1000rpm, Max 35 deg BTDC achieved at 3,500rpm


Cheers, Gregg

 
You're right, it Looks like it suffers from the same issue as the larger Crow grinds, bugger all @.050" and massive amount of advertised. 
 
What you will be finding is the car will be very doughy down low, and because of the size of you carbs it will flatten off up top as well.  Bad combo, as it will lack basically everywhere.
 
Woz

Mk1 RS2000 replica (IP hillclimb car) fitted with Ford Laser 1.8 DOHC (BP) Cossy cams, Webers, 230hp
EB XR8 5sp, heads, cam, extractors.
http://www.facebook.com/p...rmance/135194779879292
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Noono
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Re:Mild Pinto rpm @ max power? 2013/03/04 22:00:29 (permalink)
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spigot

I have had a very bad experience with waggot.

Have you done a compression test? Average 195 psi cranking

Have you verified the actual cam position? was set at 108 deg atdc if that's what you mean

Have you tried loosening up the clearance on the lash, this will simulate a smaller cam? No


Thanks for all replies
Cheers,
Gregg
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ratta tat tat
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Re:Mild Pinto rpm @ max power? 2014/06/08 00:11:24 (permalink)
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I compression tested my pinto a couple of weeks ago with the Crow Mild Street Cam (26874)
 
Cranking PSI was 180 on all four cylinders
 
I have to say the motor (and carb) has been built very well. Loads of torque, good idle and just feels very reliable I guess because all the power's down low and the engine doesn't need high revs to get off its arse
Woz your guess was bang-on. Power's gone by 5500-5800rpm 
post edited by ratta tat tat - 2014/06/08 00:26:15
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