there wasnt much difference in base circles, wr40 was smaller and HT1 I which ran but didnt actually include in the results was a bit bigger, but it was mainly a variation in followers i didnt always have tp adjust all the tappets.Originally Posted by stevieturbo
its a pinto you dare not reuse followers, so yes new ones for every cam.
i need to look harder to see if theres any correlation between power delievery and timing figures/ lift at TDC.
in terms of peak numbers theres not a lot to choose between any of the cams, As has been said, you can only have so many variations of a theme.
based on what ive seen, a tight twisty stage or loose i would choose the BF63, flowing tarmac stage GTS4, everything else was somewhere in between.
I dont doubt that if i stepped up to 48's or possibly 39/40mm chokes in the 45's, there would of been a bit more power ( but probably not torque) from most cams. I think its probably the same about for exhaust. As for the cylinder head, i have flow tested it and i do not think you will find any " conventional" material removed only off the shelf head that will give significantly more power.
Hi Graham,
Many thanks for such a hard work. This has been an extremely important study as far as the many off the shelf cams go.
What was the CR during the last round of tests ?
Do you think that some of these cams such as the BF63 and GTS4 for example could benefit with a higher CR as it has been always mentioned that they like around 12:1 CR ?
If time and patience wasn’t an object it would be nice to see the If the GTS4 with twin 48’s and a different exhaust manifold could get close to the mythical 200bhp, maybe with a slight increase in compression it might just do that, it is a cam with a lot of overlap @ TDC so would thrive on a bit more compression than Graham’s 11.5.1.
I think for me the most suitable cams are BF63, WR40 and RL31, what I can’t do is make up my mind in which order I would choose them. The only one of the GTS range I have tried is the 4. I wasn’t impressed with the drivability of that cam even with 36mm chokes. If Graham ever gets round to testing the Race cams I would like to see the ultimate Stock Car cam the GTS7 tested with them to see what that can do. The rest of the GTS range doesn’t do anything for me unless the 1 performed well in a Rally engine.
I also think that as a gravel rally cam, BF63, WR40 and RL31 should work very well. But, BF63 may need around 12:1. As a matter of fact, over the past years we have used BF63 and RL31 quite a lot successfully. However, we have used Ashley large bore and some other rather large bore headers on most of our builds but never a small bore Ashley.
You mentioned that drivability was not good with the GTS4 even with 36mm chokes but with that much overlap it is probably normal. I remember, long years ago I have bought a head and cam kit for a 190bhp + engine from Wilcox. Never used that head and the camshaft. But the odd thing is, the cam produces much less lift than the catalog value. Probably, as it was an overseas order from an unknown guy, they did not pay much attention to detail and got the valve length incorrect. I doubt the head is ported and prepped in Wilcox premises as well) The flow figure of that head is not brilliant too. Pity !!
Regarding the 200bhp mark, as you mentioned it is probably achievable with a really good head, 12:1CR, good fuel. If I remember correctly, Dirk has always been mentioning that 45s with 38mm chokes is good enough for 200bhp if not more in a well functioning engine.
I have an in-house dyno as well but we are just sorting out the glitches. Then, in time we will be testing some configurations as well. And of course I will post our findings.
What Graham did for us is extremely valuable !!!
It will be interesting to hear member’s experiences with some custom cam profiles, different heads ( such as raised ports etc etc ) as well.
i never changed the CR, even when i swapped heads it stayed the same its 11.3 or there abouts, ignition timing was 30-31 degrees all in all the tests, carb jetting on the Burton CNC head also stayed the same, the AFR did change a bit with the different cams but was always in the window. on teh face of its some may be shocked but given the pretty small overal change in power its hardly suprising.
im working on a couple of things now, but will get you guys more data and graphs
meanst while BF63 V GTS4
one more before i go home, same two cams but this time ive added in the GTS5
I must check the Data from the GTS5 cam, is it not similar to the Piper A8 cam that Dirk rated highly.
By the way, I was totally unaware of the existence of the GTS5. My downloaded 2019 Kent catalog does not list the GTS5. Not a bad cam at all but for the gravel with shortish straights and lots of corners it still can not beat the BF63 or RL31 in my opinion. However, gearing of the rally car may also come into play significantly.
im at home now, so cant access data, but i think the GTS5 has the RL31 beat
I've put all the cam data in an overview (except for the lift at TDC for the BF63). (sorted by duration)
Looking at the max numbers for torque and bhp you can see that there is little difference between the cams.
What to me is "fascinating" to look at is the torque-curves for the cams (especially cams that are according to the specs are almost the same) between 4000 and 5000 rpm.
Also, if anyone can explain how the manufacturer comes up with the listed powerbands for the cams, I owe you a beer!
Hi Leon,I've put all the cam data in an overview (except for the lift at TDC for the BF63). (sorted by duration)
Looking at the max numbers for torque and bhp you can see that there is little difference between the cams.
What to me is "fascinating" to look at is the torque-curves for the cams (especially cams that are according to the specs are almost the same) between 4000 and 5000 rpm.
Also, if anyone can explain how the manufacturer comes up with the listed powerbands for the cams, I owe you a beer!
Could it be pure marketing
i think the rev range is where they think about working to where they run into a brick wall!
for instance i reved most of them onto about 7500. im guessing with bigger carbs/exhaust the GTS cam may of peaked @ as 7400, in which case you could of probably un it onto 8500, where it would of made no useful power!
with most of these cams i could of found a couple of bhp more in cam timing but i was looking for best spread of power. By that i mean usually as you adjust the cam timing power and torque and both would go up, however you get to the point that either power or peak torque go up. if loosing 1 lbft got me say 3 or 4 bhp i would try a bit more, but once i got to the point that the difference was that i only gained 1 bhp for the loss of 1lbft i stopped or even backed up a bit. We are talking about rally cams afteral, A circuit racer might trade 4-5lbft in the midrange for another 3bhp at the top but even i know thats not much use in a rally car.
a good friend on mine who is not particulary technical asked me to build him a vw engine, his spec, power to 8000rpm, over 200bhp i actually gave him 220BHP it wil rev to 8 but realistically is out of steam around 7500.
the trouble is he cant keep it on cam! it takes off like a scalded cat @4K, it would be great on a race track, round straw bails and trees, nope.
RL31, BF63, WR40
Last edited by Graham; 30-11-2023 at 10:21.
rl31 gts5
you can only have so many variations on a cam!
I think this pretty much sums it up! With a single cam and this particular cam / head configuration, there isn't much variation that can be achieved.
I believe other external factors such as capacity, CR, head flow ie. all the things that affect torque (through airflow) will have greater influence on any cam chosen.
But (if you could) switch to a twin cam head (and 4v as well) and the potential mixes of profile and timing are greatly expanded - shame there aren't more
Holbay or Piper twin cam heads around as I'm sure they would be a preferred choice?
Its interesting to me that with the 'venerable' A series engine, many head combinations have been tried, including BMW motorcycle twin cam'd heads and even
Ford X-Flows through the years but no one seems to have tried alternatives on the Pinto bottom end - other than swapping to a Cosworth (which doesn't really
suit N/A), surely there must be others that have similar bore centres / stud hole patterns ?
Hmmm, a pinto bottom end with a stock ??? dohc head and 200ftlbs / 250hp NA - there's a thought LOL!
Back in the early 80’s Piper did a Twin Cam conversion that bolted onto the Pinto cast head after lopping the cam Towers off. Dave Brooks did his own version in the 90’s that was very similar. I had a conversation with him one day regarding what cams were in it and he replied they are 6R4 profile.
I think the limiting factor with the 8 valve Pinto is not the cams but the head. 16 valve heads have been tried with the Warrior, Holbay and Cosworth, most 2.0 ones were struggling to give anymore than 225, 230 bhp. I tried many permutations of the Cosworth NA, they were money pits and never gave the results that they promised.
As far as I know, Smith&Jones Engineering do have a dedicated N/A YB Cosworth since quite a while. That must be the ultimate head along the Connaught’s 16v Warrior head and also the Millington cylinder head.
Think you are right, this test shows what the head (+ carb + exhaust combination) is capable of, whatever cam you throw at it. Maybe Graham can be persuaded to dyno-test several spec heads from different companies or even one-offs with one type of cam. After he had few days of rest ofcourse ....
at some point i may try different exhaust and carb options, the two big issues are time ( lack of) and money,
Andy Burton cuts me a very good deal on stuff and has donated some bits, but no one is going to give me heads to test, even if they did theres cost of gaskets, not to mention fuel. The You tube channel brings in 4 to £5 a day so its not worth buying stuff purely to make video content, and i refuse to start advertising irreivent stuff just for the revenue, nothing makes me stop watching a video quicker than the presenter suddenly plugging unrelated stuff such as razors or kitchen knives half way through. The most profitable testing thing i do is the Classic Ford articles, but they only just cover costs of the dyno up keep.
im not playing a violin here, or after sympthy/money i do this out of personal interest and fun (?) but this cam test probably cost me about 3K to do! i have 3 cars and 2 motorcyle projects that could do with some time/money
The S&J and Millington are both bespoke things and the Warrior seems to have died of death some what. I had chance to buy one of the Warrior kits direct from the original factory that was near Manchester. The price was £2250 in 1990. Seeing this thread’s about the old iron 8v head we mustn’t get sidetracked.
I think you have gone far beyond the call of duty with these cam tests Graham, we have seen something that no one else has done, not in Public anyway. Even the cam manufacturers won’t be drawn into giving power figures or Graphs, buyers of their products are kept totally in the dark.at some point i may try different exhaust and carb options, the two big issues are time ( lack of) and money,
Andy Burton cuts me a very good deal on stuff and has donated some bits, but no one is going to give me heads to test, even if they did theres cost of gaskets, not to mention fuel. The You tube channel brings in 4 to £5 a day so its not worth buying stuff purely to make video content, and i refuse to start advertising irreivent stuff just for the revenue, nothing makes me stop watching a video quicker than the presenter suddenly plugging unrelated stuff such as razors or kitchen knives half way through. The most profitable testing thing i do is the Classic Ford articles, but they only just cover costs of the dyno up keep.
im not playing a violin here, or after sympthy/money i do this out of personal interest and fun (?) but this cam test probably cost me about 3K to do! i have 3 cars and 2 motorcyle projects that could do with some time/money
I do think maybe sometime it would be nice to see a change in carbs and exhaust manifold change to see if it’s possible to get near to 200 bhp. As for testing different heads I doubt there would many offers off companies or individuals for head loans, I doubt engine builders would want to go Public with their head let alone helping out with gaskets and consumables.
the dyno mule is still equipped with the GTS5, and is consistantly turning out 184bhp, tomorrow i will probably chuck a 3 piece Ashley on it and see what happens, when i tried that manifold on a 145/150 bhp engine it was a huge backwards step, and it was still one on a 170bhp engine. After that i may try some 39 or 40mm chokes in the 45's or possibly switch to 48's. i dont think the GTS5 will see 200bhp but the GTS4 might, even if i dont refit the 4 knowing how the two differ gives me a lot of data or a good insight to what might.
A bit of what im doing is gathering data for a clients engine, its better to put 100's of dyno pulls on one of my mules than a clients engine, i dont want to give them back a worn out engine.
I do admire your persistence Graham but you mustn’t let it get in the way of you making money with your daily work.
A few years ago there was a company advertising 2.0 Historic Pinto’s with 225bhp. Bearing in mind the engines are only allowed a 60 thou rebore and a non injection head unless there’s a spacer plate fitted between inlet manifold and head. I thought this was a strong statement to make so I asked Paul Gardner what he thought when I was collecting some machined parts. He was at a loss how they could quote that sort of power out of a legal Historic engine, he said the best he saw out of one of his Engines was 201bhp and that was only for a couple of seconds before it dropped back slightly. That engine was fitted with 48 Dcoe’s, chokes unknown, cam was either a GTS3 or 4, I can’t remember. So with your 190 bhp you’re not far off that Graham, it’s just that those last few bhp are the most difficult ones to find.
Last edited by Forest_rallying; 02-12-2023 at 05:49.
i am of the mind set that if i say im going to do something i will, probably why ive never claimed im going to give someone a 200 bhp pinto!
daily work is everyday vehicle servicing/repairs/mots etc. when im not having to help out in the office or work shop i do a bit of engine work, for the most part all the dyno stuff has to be done outside of business hours, partly because i dont have time and partly because the dyno room backs onto the office, just running the pumps and extractors made is hard to hear the phones ring, running up an engine makes it impossible
Slight change of plan this morning, i ran the engine up and it made the expected 184bhp, even though i was sure it would be a backwards step i was going to try the 3 piece manifold, much to my suprise it didnt fit! thats because since i last used it i have change the engine mounts. then i realised i would be better off testing a simpson manifold i have here this one i think
https://www.burtonpower.com/simpson-...e-simpm02.html
anyways expensive or not it was worth power 6 bhp and 2 lbft up on the cheapo ashley/sportex the GTS5 is now 190bhp
Last edited by Graham; 02-12-2023 at 15:59.
i then put some 40mm chokes in the carbs that got us just over 190bhp. 192bhp to be exact. Torque was up a bit too 166.5lbft so 79lbft per litre
going to try some 48's next,
Last edited by Graham; 02-12-2023 at 15:58.
You’re getting very close Graham.
yes, but 48's are not the answer! the last time i ran the 48's was on andys 2.3 they made 129bhp on the weber supplied 42 chokes thank you very much
on this with the gts5 they were horrid, with i struggled badly with AFR, got a lot closer with F4 tubes, which left a big lean spot around 6K, eventually i stuck a set of 40mm chokes in, that helped no end, lost the lean spot and i was able to reduce main jet sizes, waste of time though it made exactly the same 192bhp at slightly higher rpm with a slight drop in torque for most of the rev range
so what do i do next other than go home
the moral here, 45's and 38 chokes are big enough for the combo i was running, given that i got 2 more bhp with the 40mm chokes it might be worth trying a set of 39's.
Last edited by Graham; 02-12-2023 at 19:27.
What a valuable study!!!
I think, we can not thank enough to Graham!!!
looking at earlier graph the gts4 should get there as you suspect.
also have to remember that although head is very goods it is also an off the shelf item
indeed, in fact the intake manifold isnt even matched to it! its as cast because i use it on so many different engines.looking at earlier graph the gts4 should get there as you suspect.
also have to remember that although head is very goods it is also an off the shelf item
its also possible i could sneak the gts4 over 200 with a cam timing tweak, although its all a bit academic realistic how many drivers are going to know whether they have 197,198 or 200 bhp?
fully agree.
Hi Graham,
Do you think that the BF63 is still a winner for the tight twisty stages and/or loose stages over the GTS5, considering that BF63 could also benefit from today’s changes and also with a CR increase ?
And by the way it seems that GTS5 is a very potent profile!!
hmm tough questions i would expect the BF63 would show similar gains from todays changes, i suspect most of the cams could use a bit more compression. but for comparision testing thats acedemic. Based on what ive seen (running twin carbs) i would probably choose the GTS5 over the BF63
Last edited by Graham; 02-12-2023 at 20:28.
Thank you very much Graham.
Fully understand. Although GTS5 has a slightly lower torque between 4000-5000rpm than the BF63, it is producing more power at the top end. However, what little bit confuses me is as far as I have read BF63 needs at least 11,8:1 or even 12:1CR. Would this much CR hike be a game changer in your opinion ?
By the way, I did use BF63 many years ago but I can not find my build sheet to see what CR I have used and it was fitted in a less than average CFM cylinder head in comparison to today’s cylinder head from reputable head preparers. Later on, we started using RL31 on most of our gravel spec engines.
maybe not optimum, but any cam will work on less than ideal compression, by way of example i ran up an HT1 in this engine it made 185 bhp with good torque from memory, and this engine is a good ratio too low for that cam
Last edited by Graham; 02-12-2023 at 21:03.
Re other manufacturer's heads,
It has been done over the years, although not very common as it involves major engineering and you are ineligible for most, if not all, racing classes.
Mix and matching other manufactures parts in engines seems more widely accepted and common place in other countries than the UK. (most likely out of necessity???)
Also, unless you are doing the machining yourself, it becomes a cost prohibitive exercise.
Both the Mitsubishi sohc and early SAAB dohc heads have been fitting to the pinto with excellent results. (both require major work)
(This is not to be confused with the Volvo b234DOHC which the Americans etc fit on their 2.3 Lima 'pinto'... )
Shaun
Last edited by escortinadriver; 03-12-2023 at 00:46. Reason: missed quote
Posting Permissions
Reply With Quote
Bookmarks