Hi,
Does anyone have the seat to seat timing for a 285 cam such as the piper BP285 and also if possible the .050 inch timing.
Best Regards
Tom
Hi,
Does anyone have the seat to seat timing for a 285 cam such as the piper BP285 and also if possible the .050 inch timing.
Best Regards
Tom
Hello Tom,
from an old cambook: Piper BP285 cam,
timing 34/70 70/34
lift 10.8 mm
valveplay inlet & exhaust 0.35 mm
34/70 actually means its a 284 degree cam ....
Regards, Leon.
Are you taking about a pinto cam?
I pressume so,
The pinto BP285 valve timing is as follows,
In opens 27 btdc, In closes 63 abdc,
Ex opens 73 btdc, Ex closes 37 atdc.
270 deg inlet 290 deg exhaust.
No 1 inlet valve fully open @ 108 deg atdc.
This is a very good cam for fast road or competition on tracks with lots of tight corners.
160 to 170bhp is about the max you will get with this cam.
Here is a link to the pinto cams piper makes.
http://www.pipercams.co.uk/NewPiperW...CamFrames.html
Thanks for the replies. I should have been more clear in my question but it is in fact for the Pinto engine. The engine will go into a tarmac rally car so may be a bit lacking in power for the application.
Regards
Tom
That's the BP285/2 (assymetric); since they don't make the old one any more I think they just named it the BP285.Originally Posted by RWD fords rule
The cam is old so it is most likely the one from your old cam book. I did some calculations and ran it through the engine simulator and it tells me that the max power will be at 7200rpm if the engine is ported with correct length inlet and exhaust. RPMs are a bit low for really big power but gives good torque.
Regards
Tom
What engine simulator did you use and where did you find it?
Aslo do you have formulas for inlet and exhaust length?
A BP300 Rally cam is the next step up in the Piper cam list.
Power band 2500 to 7500
292 degree
12.57mm lift
Timing = 40/72 72/40.
It is an excellent rally cam.
Next step would be a 947 cam
Power band 3000 to 7900
300 degree
12.95mm lift
Timing = 46/74 74/46.
I wouldn't recomend going for the 947 cam unless you are using forged pistons and 12 to 1 compression.
Kent cams also have good cams but they all seem to have a little more duration than Pipers cams for a given type of cam.
Example=
Kent RL31 Rally cam
power band = 2750 to 7500
Duration in 304 ex 297
lift in 12.7 ex 12.44
Verses
Pipers BP300 Rally cam
power band = 2500 to 7500
Duration in & ex 292
lift in & ex 12.57
Also, all pipers cams are chill cast but kent only do a couple of chill cast cams such as HT1 cam.
Trust me, Piper are the best!
I have two simulators Dyno2003 and engine analyser pro. The Dyno2003 is very good for some quick testing an comparisons between two cams and is also very easy to use. The Engine analyser pro is much better but much more complicated and requires much more input from the user but has the advantage of giving a more realistic output.
I am working on an excel spreadsheet that can be used to calculate the inlet and exhaust lengths when you want to tune for a particular max rpm. The exhaust calculations are only for a 4 into 1 system but I may be able to do a 4-2-1 system eventually. It is quite interesting to look at the inlet lengths for a peak at a particular RPM
eg. Inlet length form back of valve to the end of the Trumpets of 410mm gives peak ramming effect at 7574 rpm. There is another peak at 5616 rpm which is fairly good for the BP285 cam as peak power is 7250 and peak torque is at 5000rpm The only problem with this length is it will not fit inside the engine bay of an escort.
Best Regards
Tom
Hello,
Any one know what the tappet clearance to use with the old Piper BP285 cam. I am thinking of using 0.010 on both inlet and exhaust.
Best Regards
Tom
i'd be interested to see how this goes, i've never used any engine simulators, my experiece says a 285 cam is highly unlikely to peak at 7200 rpm much more like 6,200
Group4 - I use both those bits of s/ware as well. Where did u get all the Pinto info required for Engine Analyser Pro ? I hope ur not using the American Pinto specs.
I am not sure where I got the files but the output from ea pro is about 105 bhp with the settings which is not too bad. I find ea pro hard to use as there are so many parameters and it is difficult to know what to use. I find that dyno2003 much easier to use but I would not think it is as accurate. It has a nice feature where you can iteratively test different cam profile to see what timing gives the best torque or power between set RPM values.
I have attached the ea pro file for the pinto, all that you need to do is rename to remove the .txt extension.
Regards
Tom
Last edited by Group4_Mark2; 06-01-2008 at 17:20.
i have attached a word-document. it shows how i ended up with PIPER bp285 long time ago...
i used 1600 head, with modified gp1 valves. i had to shorten valves quite a lot.
11.8:1 compression ratio with 99oct normal pump gas.
Cheers, Tepi
Thanks, Dyno2003 is'nt to bad we saw a 5kw differance from what it gave and what the dyno read.
Graham is right here, my old engine had a BP285, and it struggled to rev over 6500rpm, and that was with 48's and a half decent manifold.
Tom,
from the same old cambook both inlet and exhaust clearance should be 0.35 mm (or 0.014 inch).
Regards, Leon.
Hi,
Thank you for the info. There was a bit of a rush in the end and I did not see the info on the gaps so I had set the inlet to .2mm and the exhaust to .25mm already. I measured the cam timing and was getting inlet = 25/71 and exhaust = 73/40 at the valve which gives durations of 276 and 293 degrees with the cam set at max lift at 109 degrees. I did not do the head but when I measured it the compression ratio was only 10.5:1 which is lower than exected.
We will see how it goes
Regards
Tom
Last edited by Group4_Mark2; 07-01-2008 at 00:25.
Thanks for all your help on this one. If anyone is interested The following dyno plot is from Dyno2003 and is from the actual valve events as measured using my installed cam.
I am thinking of increasing the valve gaps on the exhaust valves as the duration is very long in comparison with the inlet. I reduced the valve timing by 3 degrees and the following dyno plot shows and increase of nearly 3bhp. While the actual power from these plots may not be entirely representative of the actual power I trust that if it shows a relative change that this change will be reflected in the eingine.
If anyone is interested I can try different cam profiles while leaving everything else the same.
Best Regards
Tom
Last edited by Group4_Mark2; 08-01-2008 at 10:19. Reason: images do not seem to be working
BTW the plots on the last post were done with 12:1 compression ratio. Using the engines actual compression ratio of 10.5:1 the power drops by over 10bhp
Regards
Tom
Tom,
195 bhp from a 285 cam???
Leon.
Hi,
The program always over states the power figures. With 12:1 compression ratio I would expect 175bhp maximum from the engine combination. With the actual engine with 10.5:1 compression ratio I would expect a maximum of 160 - 165bhp
It would be nice if it could give the power as in the previous plots
Regards
Tom
i have no dynochart. but i did 14.57/100mph on dragstrip.
3.89dif with lsd and 205/60-13 street tires. total weight was 995kg.
i think it could made 175-180bhp
Cheers, Tepi
I would be happy with that. What would be the weight of a MK2 rally car with pinto, quaife, cage and sailbury axle. I will connect up the G-tech pro and see what the rear wheel HP is. I would guess about 875kg
Regards
Tom
Bit low that mate, the cage does add a fair bit, you'd probably looking at about 950kg there or thereabouts.
Got the engine started today and was hoping to give it a bit of a run. It started on the second or third turn of the engine which is not bad but there was a terrible noise coming from the back of the engine from what seemed to be the head. I had visions of having to strip the engine again. We switched it off to think about what could be the problem and decided to give it another go. Started first go again but same noise. Pressed the clutch and noise gone. Engine idled as completely smoothly. The gearbox has just been rebuilt but it sounds like there is something very wrong with it. So it has to come out again tomorrow and back to the gearbox guy to see what is wrong.
Rgds
Tom
Tom,
have you checked that there is a spigot bearing and that it's the correct size???
Leon.
There is a spigot bearing and it is in good condition. Normally that would make noise when the clutch pedal is pushed in but this is the opposite and makes a lot of noise when the clutch is engaged in neutral.
Regards
Tom
i assume the gearbox has got oil in it?
Had just added new oil. The gearbox also seemed to be loading the engine so was in bad shape. I personally hate gearboxes and anything to do with them so we will see what the expert comes back with.
Clutch release bearing?
normally release bearings only make noise with the clutch pressed
I am thinking it is the main bearing on the input shaft to the gearbox. It was making a terrible racket but at least the engine is Ok. I had visions of a total re-build for a while. I will try to put up some more photos but my phone camera is refusing to connect to my PC at the moment.
Regards
Tom
Gearbox came back and was fitted today. Working perfectly now. The guy who did it said there was nothing wrong with the box, he just stripped it down and re-assembled it and all was OK afterwards. Sounds like a tall tale to me, most likely trying to cover up for some silly mistake first time round but at least it is OK now.
Regards
Tom
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