Photos of the head and dyno sheet
Photos of the head and dyno sheet
Still confused !!!
Although RL31 is one of the best profiles from Kent ( as it is ), I doubt it can create this much torque with the calculated/existing CR.
On the other hand, as far as I know, RL 31 can work with up to 11.5:1 but the sweet point should be 11.0:1 for RL31. I am sure, friends here might have share their experiences with the well known RL31.
Graham - Thank you. Link below:
hawk1903 - the torque was confirmed on two dynos (one showed 210nM, the other 207nM). The only thing different was power but I believe more in the latest/smaller one (above).
If you think that for this cam CR 11:1 is the optimal then I should skimm only 1mm more...wonder if that can significantly help with power though..? Btw - new 2.25" Ashley manifold is also here
Well, 11:1 is what I wouls use if I was building an engine with RL31 due to our hot climate etc issues. However, RL31 may accept very little more CR as well, may be even up to 11,5:1
Here at TS, there are friends very familar with RL31 and successfully used RL31 in their builds.
If I remember correct, Graham build a very nice engine with RL31 but I am not sure about the capacity of that engine at this moment.
Certainly it is a good cam out of the box but there can always be much better custom profiles which is designed by knowledgeable people..
Well, 11:1 is what I wouls use if I was building an engine with RL31 due to our hot climate etc issues. However, RL31 may accept very little more CR as well, may be even up to 11,5:1
Here at TS, there are friends very familar with RL31 and successfully used RL31 in their builds.
If I remember correct, Graham build a very nice engine with RL31 but I am not sure about the capacity of that engine at this moment.
Certainly it is a good cam out of the box but there can always be much better custom profiles which is designed by knowledgeable people..
Regarding the target chamber volume, it is hard to say cut/skim 1mm and you will reach to xy cc. I normally skim bit by bit and keep measuring the chamber and modify the chamber shape if it is needed etc.
thank you. I have to stay now with a ready / of the shelf cam as it is. Any other opinions from "TS friends" familiar with RL31 ? what CR you have/recommend for this cam? Unfortunately I have to decide by morning - last moment to do the skimming (then workshops vacation, and then the rally). M.
RL31 (BP300 for Piper customers) is indeed a very nice profile. It's always working in a good prepared engine. It was still in the days of trial and error I already found this as a good torque / power cam. This cam is perfect for a very fast road / track day car.
You can never go wrong, over the top with this cam and will give high Bhp numbers as well. RL31, A8 (Piper) and HT1e all tested in the same engine where within 4 Bhp from each other. Engine made 189 (RL31) and 193 (HT1e) Bhp. The RPM range for HT1e was higher and the engine was able to run higher in RPM but not making extra power. The RL31 did stopped sooner.
Onyd - thank you , it's very valuable info. What compression ratio you recommend for and engine with such cam ?
Guys, one more question. How much valve advance For this cam I should set (as an entry stage, before adjusting on pulley) ? I think we had something around 16 degrees in past....but I'm not sure and different garage is working on this now. Ps. Sorry for vocabulary / not professional wording
Last edited by grzelu; 12-08-2017 at 07:37. Reason: More info
Hi again,
Regarding the camshaft timing ( via the adjustable cam vernier ), Kentcams catalog says, inlet valve must be open 3.33 mm @ TDC or if you are using the full lift method, Kentcams says 106 degree @ Full lift.
These figures are from the catalog. Once you decide about the static CR and build your engine and time the camshaft with either of the above figures than fine tuning of " camshaft timing " ( towards advance or retard ) best be done on the dyno along the fuel mixture ( at least to be on the safe side at wide open throttle under the load )
Note: As a general rule, regarding the camshaft timing, instead of 3.33@TDC you may start with inlet valve very slightly more open than exhaust valve @ TDC and start from here and fine tune/time on the dyno.
Due to your selected CR ( during the build ), you may end up, may be with a more advanced cam timing, for example 3.50 mm @ TDC during the dyno/rolling road session. But I believe, RL31 will be good around 3.15-3.30 mm @ TDC cam timing.
There may be other replies from TS members and they might have end up with different cam timing figure during their builds. Then, the main problem is very much related to unreliable cam manufacturers and the difficulty of getting the Pinto valve geometry correct in my opinion. At this moment, things get complicated on this particular engine.
i would time the cam in as i do most 1 degree advanced ie. full lift 105 degrees after TDC, my reasoning is, unless you know for a fact the cam will work better timed some other way its best to time it as per the manufacturers specs, i similpy go 1 degree advanced to allow for belt stretch.
RL31 timed at 105 was what gave 200 bhp on the 2.2 i built dazzle
thanks everyone for valuable comments. The head has been machined. After workshops vacation we will put it back together and go to dyno.
ok so all the calculations and skimming was done (heads height is now 91,6cm), car was put back on dyno (on wheels). Except for signifacantly different sound and little bit smoother acceleration in higher revs (but worse on lower), there is very small change in performance.... only 7Hp gained and no change in torque. Dyno chart attached. It seems very odd taking into accounbt that CR was rised from 9.68 to 11.21. Compression has been measured and rised from app. 9 to 11. What do you think ?
My impression is that we can't get anything more from this engine (unit) or maybe I'm simply tired with no proper results.
BTW - I also made a check on Carbs. They are ok and the current setup is:
Weber 45 DCOE 152G
choke tubes 38mm
main jets 145 (played with 150 and 155 but mixture was to reach)
air jets 180 (changed to larger, 200 or near due to fuel flooding during dyno)
pumps 45
emulsion tubes F16
Idles 55f9
Sorry I've got not time to read whole topic but did you made a change in camshaft?
What where the changes, more as raising the compression ratio ?
Was it 140-145 bhp at the wheels or at the crankshaft?
In my experience F16 tubes in a newer 45DCOE carb is no good.
A 145 main jet is consistent with 150 something bhp.
Why is a 145 main jet in consistent with +/- 150 Bhp ? I had a Golf 2 ltr 16V in Rally-Cross a few years ago. Made 200 Bhp and a lot of torque. Almost standard engine with perfect balanced cams. Running 45 DCOE, 36 mm chokes, F16 emulsion tubes and 145 main jet.
Last edited by grzelu; 10-01-2018 at 23:40.
Hi grzelu powers at the wheels good results what type of head are you using who ported it cheers mario.
7 Bhp at the wheels extra from only a manifold change (or head work). You should be happy. Please note, you always come to a point where finding extra power is a lot more difficult as when the engine is still on 110 Bhp and you want 120. That's easy.
As I always say, raising the compression ratio from 9 tot 10 does make a noticeable difference. Raising from 10 to 11 makes a lot less extra power. Usual little over 10,5 / 1 it all drops dead for a normal rally camshaft.
Slight drop at low RPM can come from exhaust and / or flow work. As can be the extra power on top.
given that we are talking power at the wheels, it looks like a decent power gain to me, not only have you got more but it hangs on to it much better, thats a much more user friendly power curve, ok you have lost a bit low down, but in a competition car if your ever using full throttle down at around 2500rpm, then your in the wrong gear!
Nearly 20 years ago now i brought a Mk2 RS 2000 from Rally & Competition Equipment , it said 180 hp Pinto on 48's .... well got it home had a tinker then popped it on the dyno at work that i operated. It was 124hp flywheel !!!!
The head was removed and skimmed to get 10.5.1 valve heights done and another inlet manifold .... it was running a GP 1 cam and 44 inlet & 38 exhaust valves and 36mm chokes and 40 mm trumpets.
In the end i got 136 at the wheels 165 flywheel and 149 ft it drove like a injected motor very smooth and grunty.
So it only takes a few things not quite right or miss matched or " to big " to get a poor result and driving like a pig ...
Last edited by Dan Johnston; 11-01-2018 at 15:42.
Over 20yrs ago my car went on the rollers.
It was running 48's what was said to be slightly better than a grp1 cam a big valve head and 93.5mm pistons on a cossie crank an rods with cast pistons with about 10.8.1 cr. It had a 3pce manifold, not sure who it was made by though....
It started off with the operator saying it wasnt running well and putting out about 125bhp@ the wheels. He asked me if I had any other plugs I could put in it while he changed messed about with jets, I said I only had some standard ones. He said ok, give them a go.
It went from that to 160bhp @ wheels. He said he'd never seen a set of plugs and some jetting make another 35bhp.
I remember it being really crisp an clean but only ever revved to 7k then stopped dead. I dont know how much torque it put out.
Last edited by rallyrob; 11-01-2018 at 16:08.
I always say, it's very easy to loose 20 Bhp by doing things wrong than gaining and other 5 Bhp on an already correct build end setup engine.
Most people get stuck somewhere between 160 and and 175 Bhp. I've never seen any engine making 185 Bhp or more without a pro build head from company's like Vulcan CNC-heads etc..
thanks for all the comments. On one hand I should be happy with results but on the other I'm way below results that others achieve.
OK, maybe 7hp gain isn't bad after changing the exhaust and CR but where to look for significant change? My problem is towards current performance after all mods made to the engine from the beginning (not lat only).
Onyd - you say that most people get stuck somewhere between 160-175....well, I got stuck on 145-150.
I also remember Graham building engines around 200Hp...Ok, he is genius but I was aiming at 180 with this set up and more with different carbs, cam etc.
Please advise where to look....or maybe I have to switch to an 16v modern engine and convince local scrutineers to treat it as replacement for BDG. Otherwise I can't compete in FIA3 class where my colleagues cars have 200Hp + (on wheels)
OK, this was 150 Bhp flywheel power, not engine power. For een RL31 it is rater low. But it's all in the head. Second, none of the other colleagues have 2 ltr Pinto's with 200 Bhp at the wheels. This can only be done with 16V modern engines like BDA, Warrior, etc...
If you want a 190 Bhp Pinto engine, very simple, you order a Stage 4 cylinderhead from Vulcan (or other pro head), fit Piper A8 or HT1e camshaft, get yourself a set of 45 mm DCOE and 38 mm chokes, put a decent ignition on it (like Bastek), Ashley 4-2-1 Big-bore and you got it. You need a strong bottom end and valve pocket in your cast pistons.
Even poor setup these heads still make 180 Bhp+ at the flywheel. Believe me, it'a ll in the head. I had 2 engines in less than 3 days one after the other on my dyno. Complete same stuff, even sharing the same exhaust. One made approx 187 Bp, the other barely 165 bhp. Only the head work was not the same. The 165 Bhp was also build by a so called pro engine builder but I believe this guy must have been drunk.
at the moment we are all guessing, but you cam, carbs, compression and exhaust should all support 180bhp, so either they dyno reads very low or the head doesnt actually flow well at all, most likely the issue is the head. i assume it is a 2.0 carb (not injection) casting? do you have any pictures looking down the inlet ports? does the cam give the valve lift its supposed to?
it would be expensive but if you send me the head i could flow test it, then we would have some idea as to whether its any good or not
Approx 25 year ago I've build several Capri engine, all round big valve heads bought in UK. One I had back on my dyno a few years ago for a camshaft swop. It made +/- 145 Bhp with RL31 but was setup with 44 IDF. You may expect little more with 45 DCOE.
The same cam went into a rally engine I had in at the same time (I sold the cam second hand). This engine made 187 Bhp, Vulcan head and Weber DCOE 36 mm chokes.
Believe me, it's the head that sets the max power, not the cam. This same rally engine made little over 190 Bhp with HT1e and 189 Bhp with Piper A8. And this result was also confirmed on a other dyno (Superflow).
RL31 and BP134 compare
Please note, this power issue is not only related to Pinto's, it the same with all kind of engine. My friend got a flow bench and does work a lot with it and ofter testing a head he always makes a power quote by estimating. He is always very close
I see 2Ltr VW T1 engine coming in with almost standard heads and making 130 - 140 Bhp and then you got "fully build" 2,3 Ltr engine making 125 Bhp (and not a few). Just to compare.
Ok so the head is the issue almost for sure. The cam is right. Maybe the chokes little to big (38mm) but shouldn't affect the output that much. Also the torgue is very good so it's the power that doesn't follow.
Graham - my head was originally injected version from sierra.
I will also PM you in regards to your suggestion.
Others - do you know how much a Vulcan heads cost? I have a spare engine and think weather not to build a new engine and use current one as spare / back up. On the other hand I'm considering putting a newer affordable 16v engine but must be ford and as close to BD as possible (or at least not have and structural / modern advantages over BD). Was thinking of YB without turbo but they miss torgue. Zetec seems cheap and structurally 'worse' then BD so maybe local ASN would allow it. What engines your regulations favor for old escorts (as replacement) ?
yb without turbo is very expensive to great real power from, most dont make much more than a much cheaper pinto can
38 mm wil indeed not "choke" the max power. Can have negative effect on torque.
There is nothing like "cheap power". Specially not if it has to be old school Ford and close to BDA. Once you want to go over 200 Bhp, let say 240, even a 16 valve engine will be expensive. A stroked, over-bored Pinto does make nice Power and Torque but again, not cheap.
The Duratec Mazda chain drive engine is another one to consider. A decent head as std that requires little modification if any to get over 200bhp. No free lunch though as you'll need management and bodies, rod and pistons, cams, ex manifold and much more including belhousing engine mounts and so on.
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