The power increase is probably only down to better rocker ratio geometry, any move away from a std camshaft on an Xflow means adjusting the std rocker adjuster by screwing it down more, this then moves the pushrod ball pivot point away from the std position to take up the the clearance of the smaller base circle on the performance camshaft, as a result the pushrod ball then moves further out from the std sweep of the central tip of the adjuster ball by as much as 1mm, this then reduces the theoretical rocker ratio geometry, I've studied this in detail recently on my own Xflow, I measured valve lift for a BCF3 camshaft and found that I was only getting full valve lift of 9.4mm and not the advertised 10.47mm! I simply wound down the adjuster to get the correct valve clearance then measured the lift to find the disappointing result. I worked out that the center pivot point of the ball on the adjuster had indeed moved away from the central pivot sweep by 1mm, this change then meant that the std Xflow theoretical rocker ratio of 1.52-1 was now down to 1.40-1 and that's where my missing lift went, the mathematics does not lie in this case. My answer to this was to shorten the rocker posts by 2mm or so to bring that adjuster ball back to the std position, that sort of worked as I got some missing valve lift back lift back by 0.5mm 9.9mm, this shortening of the rocker post presented a new problem, the central pivot of the rocker to the rocker tip then was reduced as the rocker was tilted further back, the solution to that was to re shape the rocker tip pad to a more favorable shape & position, this then clawed back my rocker ratio geometry to the std Xflow 1.52-1 according to the mathematics, I finally had 10.3mm of Valve lift, still not the advertised 10.47mm as claimed by Kent cams, so I decided to measure cam lobe lift to find I was only getting 6.9mm & not the advertised 7.15mm, well I suppose you never do get the advertised lift. So if you ever fit any type of performance camshaft to an Xflow check your valve lift accurately because I bet your not getting anywhere near the advertised valve lift, this will be a result of very reduced rocker ratio geometry because of the adjuster & a very much milder camshaft profile compared to what you think your actually getting. Camshaft duration will also take a hit in this case, thus reducing performance further. Come on Graham from penguin motors show us a video of what valve lift your actually getting from your BCF2 with the std & roller rockers.
one think is the peak power, but what really is surprising is how evenly it makes more power across the whole rev range. a most pleasant upgrade i imagine
Nice, power right through the rev range and maybe it wanted to roll over even higher up the rev range looking at that. I'll never get tired of the x-flow or anyone still working and running them. The best low end grunt noise of any engine I've ever heard, magic.
I always love your XFLOW videos! I bought my roller rockers for my 1700XF maybe 10 years ago just for peace in mind. I never aspected this to have a small power gain - Voila
I've had a set on my xflow for nearly 20 years. Bought them for similar reasons as you described. Also, peace of mind with beefy springs and a high lift cam. My guess is the roller bearings reduce parasitic loss. They are very free moving under load compared to standard rockers. Btw, they dont help much with bad geometry. Heavily skimed heads need the posts shimming to avoid valve guide wear. Dont ask me how i know 😢
Another fascinating video, I do remember looking at the crossflows hotrod racing at Wimbledon in the late 1970s, a few at least had a strange braced arrangement where the rocker shaft and pillars were effectively part of the lower section of the rocker cover. (I have described it badly) I am sure you know what it looked like. Of course at the time we did not appreciate just how high the engines were revving relative to our roadgoing tuned X-flows. I have recently seen a channel "Sorceress" where they have done a deep dive into valvetrain dynamics, you might find it interesting. They have oscilloscope style plots of valve position at varying RPM. On a lighter note no-one disputed that my 1700 crossflow was 130hp, 40 odd years later you may have exposed me as a liar... (I may have sometimes added another 10hp to that) 🙂
To be honest I can’t see what effect the sleeve would have, the rockers do not walk sideways even if the did it wouldn’t damage a valve. I’ve known plenty of engines which spend there whole life screaming around at 8k that still have springs
Good explanation Graham. I had myself steel rockerpost in the past, because at that age i believed that it was more rigid. But after many years, and considering road use, no more then 6000 rpm shifts, it may be not worth the money spended. I have seen roller setup from Yella Terra also sold by Burton's , but expensive, Is it well money spend for road use, that's a question i would answer by no. It doesn't in my humble opinion. For racing yes. And how good are they? I question i have. Do you know About the Burton's cam profile BLF22 for the Kent engine? I still kept one in very good shape. May want to save it for the lil'Cortina 1200 cc.
Anyone seen one of the 2-piece Piper rocker covers that Piper made for Ford Kent engines in the 1960s/70s, with integral rocker shaft mounts ? Did away with individual rocker posts , and supposedly held the rocker shaft much more rigidly than even steel rocker posts. That in combination with Burton roller rockers ought represent the ultimate Kent engine rocker gear.
yes i remember them, the two biggest issues were cost and oil leaks, but modern sealants would put paid to the oil leaks. ultimately i dont think it achived anything regular steel posts couldnt
Seeing as many phones nowadays have the ability to record video in super slow motion , would it be possible to see what's happening in close up with the rocker cover removed?
I am sure the roller bearings on the shaft help and perhaps stiffness , but as someone else said, > is the rocker ratio the same, you can measure with a micrometer point to point and they appear the same, but installation of shaft height and points of contact between rocker designs are quite capable of giving, different ratios
yes i understand, as far as i know there is no such thing as an uprated pushrod for this engine, apart from which the push rod holes in the heads are pretty thin, drill them out and you WILL break through to the inlet ports given a decent sized inlet port
Good stuff as usual. What kind of valve spring pressure are you running at the seat for these things? I expect you can ran just a hair less with lighter rockers too
the head was an off the shelf head supplied with double springs, i didnt do any spring pressure checking but i did remove the inner springs before fitting it, at a guess they would be something like 85 seat and 160 on the nose.
I'd think one would see a bigger difference with high lift cams with steeper ramp angle. Roller would also put less stress on cam lobe so less friction wear in the long run
dont know, but that was why i had them in the first place to try and wear them out, i couldnt, and if a days high rpm running hasnt worn them then you can reasonably assume they will last a good long time all things being well
Be interesting finding out if gain is due to less friction. Maybe friction difference between rollers and standard rockers could be crudely measured with torque wrench on crankshaft , and measuring torque required to rotate crankshaft. @@PenguinMotors
Can you do a pull with just the steel post & shaft less the roller rockers to see if it makes a difference or roller rockers on standard post & shaft I had the steel post & shaft but couldn’t afford the rockers at that time but was always curious if it made a difference without the rockers
No. These are a cross flow. Years ago a couple of companies made roller followers for Pintos because of cam failure issues but you needed their matching camshafts too. Just not necessary now with the quality of current day cams.
@@richardjackson5380 I’m not sure why I just typed “Makes Sense” when the 1.6L in my 73 is a crossflow. I’m not going to invent excuses why I didn’t respond properly. My 71 is a 2.0L, my 72 is a 2.0L and the 73 is the baby of the bunch with the 1.6L
@@PenguinMotors it's interesting the difference in cost of tuning an original engine and just putting a modern engine in. I've got a Zetec in my 7 that cost next to nothing to get 150bhp. My MGB still has the original B series and I'm seriously considering a Mazda or ford engine as an alternative to tuning.
I guess it's relative to how far you want to push the whole setup too. Over this kind of bhp on the way to 200ish you would need them, this is just a good display of what you get on a low budget build with top end parts bolted on.
You ready boys? Let's make some noise... My favourite TH-cam catchphrase
The power increase is probably only down to better rocker ratio geometry, any move away from a std camshaft on an Xflow means adjusting the std rocker adjuster by screwing it down more, this then moves the pushrod ball pivot point away from the std position to take up the the clearance of the smaller base circle on the performance camshaft, as a result the pushrod ball then moves further out from the std sweep of the central tip of the adjuster ball by as much as 1mm, this then reduces the theoretical rocker ratio geometry, I've studied this in detail recently on my own Xflow, I measured valve lift for a BCF3 camshaft and found that I was only getting full valve lift of 9.4mm and not the advertised 10.47mm! I simply wound down the adjuster to get the correct valve clearance then measured the lift to find the disappointing result. I worked out that the center pivot point of the ball on the adjuster had indeed moved away from the central pivot sweep by 1mm, this change then meant that the std Xflow theoretical rocker ratio of 1.52-1 was now down to 1.40-1 and that's where my missing lift went, the mathematics does not lie in this case.
My answer to this was to shorten the rocker posts by 2mm or so to bring that adjuster ball back to the std position, that sort of worked as I got some missing valve lift back lift back by 0.5mm 9.9mm, this shortening of the rocker post presented a new problem, the central pivot of the rocker to the rocker tip then was reduced as the rocker was tilted further back, the solution to that was to re shape the rocker tip pad to a more favorable shape & position, this then clawed back my rocker ratio geometry to the std Xflow 1.52-1 according to the mathematics, I finally had 10.3mm of Valve lift, still not the advertised 10.47mm as claimed by Kent cams, so I decided to measure cam lobe lift to find I was only getting 6.9mm & not the advertised 7.15mm, well I suppose you never do get the advertised lift.
So if you ever fit any type of performance camshaft to an Xflow check your valve lift accurately because I bet your not getting anywhere near the advertised valve lift, this will be a result of very reduced rocker ratio geometry because of the adjuster & a very much milder camshaft profile compared to what you think your actually getting. Camshaft duration will also take a hit in this case, thus reducing performance further. Come on Graham from penguin motors show us a video of what valve lift your actually getting from your BCF2 with the std & roller rockers.
love these no bs tests, great content mate
Thank you!
one think is the peak power, but what really is surprising is how evenly it makes more power across the whole rev range.
a most pleasant upgrade i imagine
Nice, power right through the rev range and maybe it wanted to roll over even higher up the rev range looking at that.
I'll never get tired of the x-flow or anyone still working and running them. The best low end grunt noise of any engine I've ever heard, magic.
I like your no nonsense approach,say it as it is👍💯
Right on
285 cam was by far my favorite in my road car
I always love your XFLOW videos! I bought my roller rockers for my 1700XF maybe 10 years ago just for peace in mind. I never aspected this to have a small power gain - Voila
I've had a set on my xflow for nearly 20 years. Bought them for similar reasons as you described. Also, peace of mind with beefy springs and a high lift cam.
My guess is the roller bearings reduce parasitic loss. They are very free moving under load compared to standard rockers.
Btw, they dont help much with bad geometry. Heavily skimed heads need the posts shimming to avoid valve guide wear. Dont ask me how i know 😢
Another fascinating video, I do remember looking at the crossflows hotrod racing at Wimbledon in the late 1970s, a few at least had a strange braced arrangement where the rocker shaft and pillars were effectively part of the lower section of the rocker cover. (I have described it badly) I am sure you know what it looked like. Of course at the time we did not appreciate just how high the engines were revving relative to our roadgoing tuned X-flows. I have recently seen a channel "Sorceress" where they have done a deep dive into valvetrain dynamics, you might find it interesting. They have oscilloscope style plots of valve position at varying RPM. On a lighter note no-one disputed that my 1700 crossflow was 130hp, 40 odd years later you may have exposed me as a liar... (I may have sometimes added another 10hp to that) 🙂
what you describe was a Piper intgeral rocker box
@@PenguinMotors thank you, I guessed that you would know!
The rocker sleeves are useful, have had a rocker fall from the valvehead. Changed the springs to sleeves next day.
To be honest I can’t see what effect the sleeve would have, the rockers do not walk sideways even if the did it wouldn’t damage a valve. I’ve known plenty of engines which spend there whole life screaming around at 8k that still have springs
Interesting comparison, thanks for posting.
Good explanation Graham. I had myself steel rockerpost in the past, because at that age i believed that it was more rigid.
But after many years, and considering road use, no more then 6000 rpm shifts, it may be not worth the money spended.
I have seen roller setup from Yella Terra also sold by Burton's , but expensive, Is it well money spend for road use, that's
a question i would answer by no. It doesn't in my humble opinion. For racing yes. And how good are they?
I question i have. Do you know About the Burton's cam profile BLF22 for the Kent engine? I still kept one in very good shape.
May want to save it for the lil'Cortina 1200 cc.
no BS in your vid`s mate , the way it should be
Anyone seen one of the 2-piece Piper rocker covers that Piper made for Ford Kent engines in the 1960s/70s, with integral rocker shaft mounts ? Did away with individual rocker posts , and supposedly held the rocker shaft much more rigidly than even steel rocker posts. That in combination with Burton roller rockers ought represent the ultimate Kent engine rocker gear.
yes i remember them, the two biggest issues were cost and oil leaks, but modern sealants would put paid to the oil leaks. ultimately i dont think it achived anything regular steel posts couldnt
Seeing as many phones nowadays have the ability to record video in super slow motion , would it be possible to see what's happening in close up with the rocker cover removed?
I am sure the roller bearings on the shaft help and perhaps stiffness , but as someone else said, > is the rocker ratio the same, you can measure with a micrometer point to point
and they appear the same, but installation of shaft height and points of contact between rocker designs are quite capable of giving, different ratios
You get slightly variations in ratio with standard rockers, but a few thousands of lift change isn’t going to make much difference.
the difference between the roller/ std set is what i am pointing out, also would be worth seeing if really stiff push rods help TQ @@PenguinMotors
yes i understand, as far as i know there is no such thing as an uprated pushrod for this engine, apart from which the push rod holes in the heads are pretty thin, drill them out and you WILL break through to the inlet ports given a decent sized inlet port
Good stuff as usual. What kind of valve spring pressure are you running at the seat for these things? I expect you can ran just a hair less with lighter rockers too
the head was an off the shelf head supplied with double springs, i didnt do any spring pressure checking but i did remove the inner springs before fitting it, at a guess they would be something like 85 seat and 160 on the nose.
I'd think one would see a bigger difference with high lift cams with steeper ramp angle. Roller would also put less stress on cam lobe so less friction wear in the long run
What's the life span of the roller rockers itself?
we all think you would see a bigger gain with more radical cams, but for me teh real takeaway from this is that even the mild engine benefitted
dont know, but that was why i had them in the first place to try and wear them out, i couldnt, and if a days high rpm running hasnt worn them then you can reasonably assume they will last a good long time all things being well
Be interesting finding out if gain is due to less friction. Maybe friction difference between rollers and standard rockers could be crudely measured with torque wrench on crankshaft , and measuring torque required to rotate crankshaft. @@PenguinMotors
Can you do a pull with just the steel post & shaft less the roller rockers to see if it makes a difference or roller rockers on standard post & shaft I had the steel post & shaft but couldn’t afford the rockers at that time but was always curious if it made a difference without the rockers
That engine is off the dyno now, but if i get a chance in the future i will
Have you tested different ratios rockers and do they make more power.
ive not tested different ratios yet
That's for your replys, I love your videos and learning alot.
is there any length difference that will increase stroke/duration
they are stock rocker ratio
But is the ratio the same,
yes it is
Would those fit on my 1973 Pinto 1.6L?
Overhead valve rockers on an overhead cam engine? Er… what do you think?
No. These are a cross flow. Years ago a couple of companies made roller followers for Pintos because of cam failure issues but you needed their matching camshafts too. Just not necessary now with the quality of current day cams.
Makes sense.
@@tonylockhart1963
Who has an overhead cam engine? I don’t?
@@richardjackson5380
I’m not sure why I just typed “Makes Sense” when the 1.6L in my 73 is a crossflow. I’m not going to invent excuses why I didn’t respond properly.
My 71 is a 2.0L, my 72 is a 2.0L and the 73 is the baby of the bunch with the 1.6L
So roughly £250 per bhp.
Most people will buy new shaft, spacers and posts anyway so what cost then? but that wasnt really the point of the test, it was what would they do?
@@PenguinMotors it's interesting the difference in cost of tuning an original engine and just putting a modern engine in. I've got a Zetec in my 7 that cost next to nothing to get 150bhp. My MGB still has the original B series and I'm seriously considering a Mazda or ford engine as an alternative to tuning.
I guess it's relative to how far you want to push the whole setup too. Over this kind of bhp on the way to 200ish you would need them, this is just a good display of what you get on a low budget build with top end parts bolted on.
It would be interesting to see the horsepower difference on a SOHC engine going from a slider cam to a roller . Great video keep them coming!