cam timing and induction lengths
Discussion
So ..
I've been at it again with a bit of experimenting ..
Car comes in, the owner is well known to me as I've run many of his cars over the years. It's a land rover tomcat but fitted with a tvr cerbera AJP8 4.7 litre engine mated to a tko600 gearbox driving through a modified land rover transfer box by rakeway engineering. All works perfectly, great job all round.
The engine however was initially a bit let down
Below is a comparison of how the car performed after a full throttle remap versus what it made after correcting the (massively retarded) cam timing and adding some induction length, and a pic of my blue pipes again haha.
You'd never believe it was the same engine, but I promise you this is the same engine on the same day (yesterday in fact, we finished after a 12 hour day at 8pm) but well worth the effort I think. 105bhp gain is the best at just under 4000rpm.
I'm still laughing about that improvement now..
I've been at it again with a bit of experimenting ..
Car comes in, the owner is well known to me as I've run many of his cars over the years. It's a land rover tomcat but fitted with a tvr cerbera AJP8 4.7 litre engine mated to a tko600 gearbox driving through a modified land rover transfer box by rakeway engineering. All works perfectly, great job all round.
The engine however was initially a bit let down
Below is a comparison of how the car performed after a full throttle remap versus what it made after correcting the (massively retarded) cam timing and adding some induction length, and a pic of my blue pipes again haha.
You'd never believe it was the same engine, but I promise you this is the same engine on the same day (yesterday in fact, we finished after a 12 hour day at 8pm) but well worth the effort I think. 105bhp gain is the best at just under 4000rpm.
I'm still laughing about that improvement now..
Good result, reminds me of a race B which came in for a dyno with the cam a tooth (18 degrees) out! Being a small engine in comparison to your V8 the effects were horrendous 
I attach a pic of the graph, the two higher lines are with correct cam timing and the highest bhp one with a little less low rpm torque is with fitting high lift rockers.
I attach a pic of the graph, the two higher lines are with correct cam timing and the highest bhp one with a little less low rpm torque is with fitting high lift rockers.
spitfire4v8 said:
So ..
I've been at it again with a bit of experimenting ..
Car comes in, the owner is well known to me as I've run many of his cars over the years. It's a land rover tomcat but fitted with a tvr cerbera AJP8 4.7 litre engine mated to a tko600 gearbox driving through a modified land rover transfer box by rakeway engineering. All works perfectly, great job all round.
The engine however was initially a bit let down
Below is a comparison of how the car performed after a full throttle remap versus what it made after correcting the (massively retarded) cam timing and adding some induction length, and a pic of my blue pipes again haha.
You'd never believe it was the same engine, but I promise you this is the same engine on the same day (yesterday in fact, we finished after a 12 hour day at 8pm) but well worth the effort I think. 105bhp gain is the best at just under 4000rpm.
I'm still laughing about that improvement now..
I work with a couple of tuners, and they love your blue intakes I've been at it again with a bit of experimenting ..
Car comes in, the owner is well known to me as I've run many of his cars over the years. It's a land rover tomcat but fitted with a tvr cerbera AJP8 4.7 litre engine mated to a tko600 gearbox driving through a modified land rover transfer box by rakeway engineering. All works perfectly, great job all round.
The engine however was initially a bit let down
Below is a comparison of how the car performed after a full throttle remap versus what it made after correcting the (massively retarded) cam timing and adding some induction length, and a pic of my blue pipes again haha.
You'd never believe it was the same engine, but I promise you this is the same engine on the same day (yesterday in fact, we finished after a 12 hour day at 8pm) but well worth the effort I think. 105bhp gain is the best at just under 4000rpm.
I'm still laughing about that improvement now..
. Now you have to fit that length under the bonnet - although curved runners are pretty common.ps
Did adjusting the cam timing bring the static compression up?
To be honest time was against us towards the end. I did a compression test after the initial bad results .. around 195 on the odd bank, 165 on the even bank .. didn't test again after resetting the cams though, just banged it back together (just removing the spark plugs requires the rear exhaust headers - and a panel at the rear bulkhead - and cylinder head cooling pipes to be removed, as you can see in the pic there's no space to get the plugs out).
The cam timing was roughly reset by removing the starter and turning the flywheel a tooth at a time until we could feel a screwdriver through the spark plug hole reach approx TDC (the starter is in the passenger footwell - it's sited backwards on the nearside of the bellhousing..) , then setting the cam followers on equal lift. The timing will still be several degrees out I'm sure, but with no crank pulley to get any reference marks on or to get a good swing on a long bar we did the best we could through the starter motor aperture with a screwdriver on the ring-gear.
We moved the cams maybe 1 tooth on both banks, something like that. Again, no measurements taken, just got somewhere around TDC and then set the followers equal .. as that was the quickest and easiest route for us to check if the engine was ever going to make any power at all, or just be a hopeless case. As it turns out it's looking very promising for being a good engine once the owner has made a longer intake setup.
The cam timing was roughly reset by removing the starter and turning the flywheel a tooth at a time until we could feel a screwdriver through the spark plug hole reach approx TDC (the starter is in the passenger footwell - it's sited backwards on the nearside of the bellhousing..) , then setting the cam followers on equal lift. The timing will still be several degrees out I'm sure, but with no crank pulley to get any reference marks on or to get a good swing on a long bar we did the best we could through the starter motor aperture with a screwdriver on the ring-gear.
We moved the cams maybe 1 tooth on both banks, something like that. Again, no measurements taken, just got somewhere around TDC and then set the followers equal .. as that was the quickest and easiest route for us to check if the engine was ever going to make any power at all, or just be a hopeless case. As it turns out it's looking very promising for being a good engine once the owner has made a longer intake setup.
Edited by spitfire4v8 on Wednesday 7th November 10:54
On the topic of cam timing....valve timing and settings things up.
Scopes are very useful tools these days, Pico always gets good reviews, but this Ukranian based setup could be a very useful tool with this "script" in their software.
nevermind dial gauges and/or guessing valve timing in real use....
https://www.youtube.com/watch?v=I3v40pcYr3g
Scopes are very useful tools these days, Pico always gets good reviews, but this Ukranian based setup could be a very useful tool with this "script" in their software.
nevermind dial gauges and/or guessing valve timing in real use....
https://www.youtube.com/watch?v=I3v40pcYr3g
Max_Torque said:
Hmm, did i miss the bit where you disconnect the fuel injector to avoid exotherming the cat to death??
What an absolutely pointless bit of kit! Basically does what a compression tester does, but costs massively more........
An oscilloscope is pointless ?What an absolutely pointless bit of kit! Basically does what a compression tester does, but costs massively more........
Live testing for compression that can also give valve timing and other things is pointless ?
And a compression tester can do that ?
And presumably yes you would disable the injector on that cylinder.
stevieturbo said:
Max_Torque said:
Hmm, did i miss the bit where you disconnect the fuel injector to avoid exotherming the cat to death??
What an absolutely pointless bit of kit! Basically does what a compression tester does, but costs massively more........
Live testing for compression that can also give valve timing and other things is pointless ?What an absolutely pointless bit of kit! Basically does what a compression tester does, but costs massively more........
"Valve timing" for diagnosis also, broadly speaking, pointless to be done via cylinder pressure, and critically, requires a FIRING cylinder to show real effects such as reversals, pressure wave tuning, blow down, residual mass fraction, internal EGR etc etc.
Max_Torque said:
Why? If the engines broke, the engines broke. Measure the compression, if it's low, you need to fix it, matter not one jot why. Usually, the moment you take the head off, the problem is obvious (or the moment you take the cam cover off if it's a valve issue)
"Valve timing" for diagnosis also, broadly speaking, pointless to be done via cylinder pressure, and critically, requires a FIRING cylinder to show real effects such as reversals, pressure wave tuning, blow down, residual mass fraction, internal EGR etc etc.
Who said the engine was broke ? And that is measuring the compression as well as other aspects. Do you never try and diagnose a problem before pulling things apart ? You know you know better than that."Valve timing" for diagnosis also, broadly speaking, pointless to be done via cylinder pressure, and critically, requires a FIRING cylinder to show real effects such as reversals, pressure wave tuning, blow down, residual mass fraction, internal EGR etc etc.
And how on earth does checking valve timing require a "firing" cylinder ?
When your engine is on a stand and you're playing with dial gauges...you dont need a firing cylinder....nor would it be easy to get one ! And you arent looking for any of those effects at that stage...because the engine isnt even running.
And it's a fair bit cheaper than a Pico !
Mignon said:
PeterBurgess said:
Wow, clever stuff, next thing we know with all this technology they'll be sending someone to the Moon!
I can think of a couple of people I'd like to nominate. Do we get to leave them up there?
Mignon said:
80 ft lb per litre is good going for a 2v lump. I can't imagine there's anything much left to find. Well, not unless you're one of the folks in here that think a Ford Crossflow can crank out 96 ft lbs per litre
Indeed .. ever since first reading your comments on lb.ft/litre I've used it as my bullsEdited by Mignon on Wednesday 7th November 17:41
t-o-meter PeterBurgess said:
Good result, reminds me of a race B which came in for a dyno with the cam a tooth (18 degrees) out! Being a small engine in comparison to your V8 the effects were horrendous
I attach a pic of the graph, the two higher lines are with correct cam timing and the highest bhp one with a little less low rpm torque is with fitting high lift rockers.
I think your graphs are wheel figures yes?I attach a pic of the graph, the two higher lines are with correct cam timing and the highest bhp one with a little less low rpm torque is with fitting high lift rockers.
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