I'm just in the process of finalising the spec pf my new 4.35 engine using the Buick 300 alloy heads, hence the sudden surge of posts.
I spoke to Real Steel regarding cams and Simon said that the only cam they had tested and recommended for the Hotwire system is the Cyclone which is a little softer than I had planned, I was thinking of something with a bit more lift to complement the Buick 300 heads.
In my ignorance, I hadn't realised that cam selection was specifically dependent upon induction systems. Is it that a plenum injection system is more sensitive to the cam than say a throttle body system which is obviously used with some pretty wild cams, Real Steel said that it can be difficult to map the fuelling with wilder cams, I only want something thats going to perform well on the road but be ok for the occasional blast on the track. I do have an Edelbrock 500 and performer manifold on my 3.5 engine so could re jet that but would prefer to go hotwire if possible and have all the hardware for it already.
Kevin.
Cam Selection.
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CastleMGBV8
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How are you planning to control the injection? modified rover ECU?
If so then I would take their advice.
If you go aftermarket ECU, drop the hotwire MAF sensor and go Map sensor instead then you would bave a wider choice as you could use revs and throttle position close to idle and Map from a couple of thousand revs.
IMHO trying to use a moded rover ECU with an engine this far from standard I don't think you will ever get it close to right over the whole rev range.
With choice of cam generally it is dependent on the whole inlet and exhoust tract, you have higher flow heads that I bet make more flow with higher lift than standard, there is no point choosing a cam that doesn't open the valves far enough to make use of that extra flow (you may need higher ratio rockers on one or both valves to get the most out of the cam and heads). The timing of the cam will have to be chosen so as to ballance out any limitations of flow on either port, ie if the exhaust flow is a bit low you will need extra timing.
Obviously the overall choice of cam timing dictates where peak power is, overlap effects the spread of power (lower LSA gives a bigger power peak for a given timing but is will be over and done with much sooner, wider LSA spreads the power band)
If this is a long stroke engine (I'm unsure of this size of rover) you may find it is easier to set up on the carb and those heads than a short stroke big bore engine for a given cam timing.
Best regards
Mike
If so then I would take their advice.
If you go aftermarket ECU, drop the hotwire MAF sensor and go Map sensor instead then you would bave a wider choice as you could use revs and throttle position close to idle and Map from a couple of thousand revs.
IMHO trying to use a moded rover ECU with an engine this far from standard I don't think you will ever get it close to right over the whole rev range.
With choice of cam generally it is dependent on the whole inlet and exhoust tract, you have higher flow heads that I bet make more flow with higher lift than standard, there is no point choosing a cam that doesn't open the valves far enough to make use of that extra flow (you may need higher ratio rockers on one or both valves to get the most out of the cam and heads). The timing of the cam will have to be chosen so as to ballance out any limitations of flow on either port, ie if the exhaust flow is a bit low you will need extra timing.
Obviously the overall choice of cam timing dictates where peak power is, overlap effects the spread of power (lower LSA gives a bigger power peak for a given timing but is will be over and done with much sooner, wider LSA spreads the power band)
If this is a long stroke engine (I'm unsure of this size of rover) you may find it is easier to set up on the carb and those heads than a short stroke big bore engine for a given cam timing.
Best regards
Mike
poppet valves rule!
Hi
Just had a look at the RS catalog, I think that cam has far to little lift to make any use of your heads, If the heads flow over .450 of lift then even with high ratio lifters you wont get any benifit from them have you a flow chart for the heads? really I think that is where you need to start.
I would think also with only 206 of duration and 4.35 litres it will be all over by 5000 revs, where do you want peak power?
Mike
Just had a look at the RS catalog, I think that cam has far to little lift to make any use of your heads, If the heads flow over .450 of lift then even with high ratio lifters you wont get any benifit from them have you a flow chart for the heads? really I think that is where you need to start.
I would think also with only 206 of duration and 4.35 litres it will be all over by 5000 revs, where do you want peak power?
Mike
poppet valves rule!
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CastleMGBV8
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Mike,
Thanks for the rapid response.
The answer to your first question is Standard hotwire with a view to rechipping to optimise fuelling and performance. May have to re-think this.
The engine will have a Bore of 94.89 x Stroke 77mm. = 4350cc.
The Heads are Buick 300 which will have 1.625" Inlets (standard) and 1.4" exhaust (increased from 1.312") Because of the existing port sizes the heads will only be given a clean up and a bit of work behind the valve seats, and the fitment of bulleted guides. I could go up to 1.7" inlets with waisted stems if it would offer an inprovement without affecting the power output at lower RPM's
I am not looking for race engine performance but looking for plenty of low down grunt with the ability to rev smoothly to 5500-6000RPM with good drivability on the road, which is one of the reasons I was thinking of using hotwire injection. I am a complete novice on EFI and obviously don't want to get it wrong which is why I always do a lot of research.
Just seen your second post whilst writing my reply, your comments on the cyclone cam are what I was thinking.
I have some flow information from Dan Jones in the states with some useful comparisons which is available on this link'
http://www.leylandp76.com/technical/tech-headflow.html
Be interested to see what you think.
Kevin.
Thanks for the rapid response.
The answer to your first question is Standard hotwire with a view to rechipping to optimise fuelling and performance. May have to re-think this.
The engine will have a Bore of 94.89 x Stroke 77mm. = 4350cc.
The Heads are Buick 300 which will have 1.625" Inlets (standard) and 1.4" exhaust (increased from 1.312") Because of the existing port sizes the heads will only be given a clean up and a bit of work behind the valve seats, and the fitment of bulleted guides. I could go up to 1.7" inlets with waisted stems if it would offer an inprovement without affecting the power output at lower RPM's
I am not looking for race engine performance but looking for plenty of low down grunt with the ability to rev smoothly to 5500-6000RPM with good drivability on the road, which is one of the reasons I was thinking of using hotwire injection. I am a complete novice on EFI and obviously don't want to get it wrong which is why I always do a lot of research.
Just seen your second post whilst writing my reply, your comments on the cyclone cam are what I was thinking.
I have some flow information from Dan Jones in the states with some useful comparisons which is available on this link'
http://www.leylandp76.com/technical/tech-headflow.html
Be interested to see what you think.
Kevin.
Change your plans for the ECU! Standard hotwire wont cope with that engine very well and by the time you pay for the dyno and chip mapping you will be cheaper and better with an after market ecu. Once you have done that then cam choice is much more open. That said if its low down torque your after you might need to revise your top end ideas. 6000rpm top with high low down torque seldom go together. An after market ECU will help with this as well as you will be able to tune it better for cleaner low down running.
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CastleMGBV8
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Mike,
I had a feeling I would have to go that route if I wanted to optimise the engine, What ECU would you recommend and any idea where I could take the car in the South East to have it set up properly. I am a little surprised that the Hotwire won't handle this engine as it's obviously used on all but the latest 4.6 engines
Sounds like I need to fit a wide band Lamba sensor when we switch the engine over. I thought to mount one in one of the collectors or is it better to have one for each bank of cylinders?
I do have an Edelbrock 500 carb and performer manifold on my 3.5 at the moment, do you think it would be better to use this after re-jetting and would this give me more freedom re; cam selection?
Kevin.
I had a feeling I would have to go that route if I wanted to optimise the engine, What ECU would you recommend and any idea where I could take the car in the South East to have it set up properly. I am a little surprised that the Hotwire won't handle this engine as it's obviously used on all but the latest 4.6 engines
Sounds like I need to fit a wide band Lamba sensor when we switch the engine over. I thought to mount one in one of the collectors or is it better to have one for each bank of cylinders?
I do have an Edelbrock 500 carb and performer manifold on my 3.5 at the moment, do you think it would be better to use this after re-jetting and would this give me more freedom re; cam selection?
Kevin.
I'm looking at the '64 300 heads so...
Right with the valve sizes you are thinking of, 1.7" on an unshrouded (by the cylinder wall) toget maximum flow through the valve you want to open it 1/4 of the valve head diamiter that works out at .425 of an inch. with valve head shrouding you want to open it further, from various articles I've read for a 2 valve head of the chevy type (which is meant to be average to good) add 25% more lift so this is around .531". looking at the flow shown for these heads on the link you posted with 1.625 valves this would seem to be sensable. Infact they seem to need .6" of lift to make the most of them. So for a start I would look for a cam that comes somwhere close on the inlet and possably look at higher ratio rockers for the inlet to make up the short fall.
Exhaust side dosen't seem to gain flow from .4 to .5 of an inch so not alot of point opening it further (they do flow well on the exhaust side though)
Exhaust flow is about 3/4 inlet flow which is what most tuners say is what you aim at so no need for much extra exhaust timing (oh I wish it were the same for the chevy!
)
you want to rev to 6000 revs, you will need atleast 225 deg of timing, I would think 235 with the extra cc the Hydrolic cams are the rs 224 or 234 but both really have too little inlet lift and too much exhaust duration (a good match for the 215 heads which they are designed for.
Mechanical flat tappet side the RS 238 looks a very good bet i(may be 3-4 degrees more than you want), if you can get some high lift inlet rockers for the inlets (and are prepared to do the tappets).
Otherwise its off hunting for a match off another site of off to comp cams catalog for a custom grind (that is how I got my cam for the chevy and they do a very good service, but you need to know what you want ground)
hope this is of some help
best regards
Mike
Right with the valve sizes you are thinking of, 1.7" on an unshrouded (by the cylinder wall) toget maximum flow through the valve you want to open it 1/4 of the valve head diamiter that works out at .425 of an inch. with valve head shrouding you want to open it further, from various articles I've read for a 2 valve head of the chevy type (which is meant to be average to good) add 25% more lift so this is around .531". looking at the flow shown for these heads on the link you posted with 1.625 valves this would seem to be sensable. Infact they seem to need .6" of lift to make the most of them. So for a start I would look for a cam that comes somwhere close on the inlet and possably look at higher ratio rockers for the inlet to make up the short fall.
Exhaust side dosen't seem to gain flow from .4 to .5 of an inch so not alot of point opening it further (they do flow well on the exhaust side though)
Exhaust flow is about 3/4 inlet flow which is what most tuners say is what you aim at so no need for much extra exhaust timing (oh I wish it were the same for the chevy!
)you want to rev to 6000 revs, you will need atleast 225 deg of timing, I would think 235 with the extra cc the Hydrolic cams are the rs 224 or 234 but both really have too little inlet lift and too much exhaust duration (a good match for the 215 heads which they are designed for.
Mechanical flat tappet side the RS 238 looks a very good bet i(may be 3-4 degrees more than you want), if you can get some high lift inlet rockers for the inlets (and are prepared to do the tappets).
Otherwise its off hunting for a match off another site of off to comp cams catalog for a custom grind (that is how I got my cam for the chevy and they do a very good service, but you need to know what you want ground)
hope this is of some help
best regards
Mike
poppet valves rule!
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CastleMGBV8
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Hi Kevin
Ive also been deliberating on cam selection. Im running a 4.6 in my MGB GT, previously had RPI piper 285 which only has 450 lift inlet and exhaust.
Ive actually just ordered a M238 from real steel and am planning to fit yella terra roller rockers.
Will be interesting to see the effects on the rolling road. Last time I had 282hp and 314 torque. Now 10.8:1 CR with Huffaker inlet and new cam.
Hope its not too clattery with the solid lifters.
Cheers
Mark
Ive also been deliberating on cam selection. Im running a 4.6 in my MGB GT, previously had RPI piper 285 which only has 450 lift inlet and exhaust.
Ive actually just ordered a M238 from real steel and am planning to fit yella terra roller rockers.
Will be interesting to see the effects on the rolling road. Last time I had 282hp and 314 torque. Now 10.8:1 CR with Huffaker inlet and new cam.
Hope its not too clattery with the solid lifters.
Cheers
Mark
I did read somewhere that EFI tends to soften the characteristics of camshafts. It might be worth bearing in mind if you decide to use EFI.
You may be able to use a slightly wilder cam than you thought
Obviously, mechanical cams will mean even more expense for lifters, adjustable pushrods or roller rockers.
Steve
You may be able to use a slightly wilder cam than you thought
Obviously, mechanical cams will mean even more expense for lifters, adjustable pushrods or roller rockers.
Steve
Live dangerously, syphon fuel, smoke in bed, run with scissors
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HairbearTE
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CastleMGBV8
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Mark,
As you principly use your MG as a trackday car you don't have to worry too much about how it will drive on the road, sounds like it's going to be a fun engine on the track though,you can always buy earplugs!
Steve
My problem is that I am intending to use a Hotwire based EFI system and Real Steel advised me that you have to be very careful with cam selection if it's going to work with the hotwire system, even with an adjustable ECU, and can take a lot of rolling road time to set up properly.
Unfortunately the only cam Real Steel have, the Cyclone does not have nearly enough lift to do justice to the 4.35 engine and my Buick 300 heads, see Kiwicars comments above, so am looking for a cam with a bit more lift but probaly not too much duration so that the car will be drive nicely on the road, may have to sacrifice ultimate BHP in favour of torque and look for a power band with a lower peak, although the Buick heads fully ported would provide a lot more power with a wilder cam, I am told over 400BHP is achievable on a full race 5.0! I think I'll have another word with Ian Richardson (Wildcat) to see what he suggests.
Kevin.
As you principly use your MG as a trackday car you don't have to worry too much about how it will drive on the road, sounds like it's going to be a fun engine on the track though,you can always buy earplugs!
Steve
My problem is that I am intending to use a Hotwire based EFI system and Real Steel advised me that you have to be very careful with cam selection if it's going to work with the hotwire system, even with an adjustable ECU, and can take a lot of rolling road time to set up properly.
Unfortunately the only cam Real Steel have, the Cyclone does not have nearly enough lift to do justice to the 4.35 engine and my Buick 300 heads, see Kiwicars comments above, so am looking for a cam with a bit more lift but probaly not too much duration so that the car will be drive nicely on the road, may have to sacrifice ultimate BHP in favour of torque and look for a power band with a lower peak, although the Buick heads fully ported would provide a lot more power with a wilder cam, I am told over 400BHP is achievable on a full race 5.0! I think I'll have another word with Ian Richardson (Wildcat) to see what he suggests.
Kevin.
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CastleMGBV8
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Having spent the last hour driving myself mad looking at cam manufacturers spec and giving myself a nasty headache, I thought I'd give it a rest and seek a bit of clarification.
Mike (KIWICAR)
I find it very confusing that cam manufacturers offer cams at advertised duration then quote another figure that appears to be the actual duration, what is actually meant by this?
Secondly in your earlier response you suggested that the deficit in lift on the inlet side might be improved by using a higher ratio rocker on the inlets only, this seems to make sense, but I have not seen higher ratio rockers for the Rover/Buick engine.
I do have to buy valve gear to complete this engine but was hoping not to have to spend a fortune in that area bearing in mind my sensible? rev limit of 5500-6000RPM
Something I did spot whilst on the Crane site was their new quick lift roller rockers which accelerate valve opening in the early stage of operation, not specifically for the Rover engine of course but could possibly be adapted, and they do have a minimum of 1.65/1 ratio.
Also the cams you suggested, would any of them work with the Hotwire system in standard or modified form, at the moment I only have the hardware of the system, ie plenum, trumpet base, manifold and injectors
so can be flexible as far as the electronic management side. I could of course use my existing carb set up Edelbrock 500 and Performer manifold which will be adequate for the job but would prefer EFI.
There was a guy with a 4.3 engine with Hotwire EFI in an MGB down at Brands last year and it ran really well, unfortunately the thought of building another engine wasn't in my mind then, otherwise I would have asked a few more questions.
Kevin.
Mike (KIWICAR)
I find it very confusing that cam manufacturers offer cams at advertised duration then quote another figure that appears to be the actual duration, what is actually meant by this?
Secondly in your earlier response you suggested that the deficit in lift on the inlet side might be improved by using a higher ratio rocker on the inlets only, this seems to make sense, but I have not seen higher ratio rockers for the Rover/Buick engine.
I do have to buy valve gear to complete this engine but was hoping not to have to spend a fortune in that area bearing in mind my sensible? rev limit of 5500-6000RPM
Something I did spot whilst on the Crane site was their new quick lift roller rockers which accelerate valve opening in the early stage of operation, not specifically for the Rover engine of course but could possibly be adapted, and they do have a minimum of 1.65/1 ratio.
Also the cams you suggested, would any of them work with the Hotwire system in standard or modified form, at the moment I only have the hardware of the system, ie plenum, trumpet base, manifold and injectors
so can be flexible as far as the electronic management side. I could of course use my existing carb set up Edelbrock 500 and Performer manifold which will be adequate for the job but would prefer EFI.
There was a guy with a 4.3 engine with Hotwire EFI in an MGB down at Brands last year and it ran really well, unfortunately the thought of building another engine wasn't in my mind then, otherwise I would have asked a few more questions.
Kevin.
Hi Kevin
there are two duration numbers quoted , the .05 (shorter one ) is the one to use, it enables you to compare durations of differnt cams using different types of lifters, the "advertised duration" is taken at .006", on a solid tappet cam the tappet clearance isn't even taken up while the Hydraulic tappet may just start lifting at .05 both types of cams should be lifting similar amounts (remember the oil in a hydraulic cam will compress a very small amount ).
Fuller explanations of cam specs can be forun on compcams website or on Iskey cams website.
High ratio rockers can be found, the buick V6 was started as a buick V8 with 2 cylinders cut off and that has been extensivly developed in the US, try looking at Yella terra they do roller rockers for the rover, I think some volvo ones can be used as high ratio rockers on a rover shaft.
Mopar engines have shaft mounted rockers similar to the rover and may be a start.
As far as the injection is concerned you have the bits you want for this set up and have not commited to a controler, the cam RS are recomending is based on the extreamly limited controler that this set up usually uses and the way you have to bodge it to work with any alterations you make to the engine, with the added restriction of the hotwire AFM. Get an aftermarket controler (VEMS, MS extra or Emerald or one of the many others) and the world is your lobster cam choice opens up because with the mapable contrloer you can actually get it to work with the mods.
If you are now only aiming at 5500 to 6000 revs then a 220 or even a 215 duration cam at .05 may be enough, if you can get the lift, however it will be a bit of a compromise unless you go for a roller lifter set up.
The choice of heads you have made really commits you to higher duration as does the larger capacity.
A bit of explanation
If you look at the flow charts for the 215 heads and the and the ford heads you will see the 215 heads at .2 of lift beat the ford heads even though at .6 lift the fords beat them hands down. Although it isn't always the case generally smaller port heads work better flow wise at lower lift. further with less timing on the cam you actually get alot of the eficiency (and power)of the engine from swirl created in the inlet port thoroughly mixing the fuel air mixture, use bigger ports and then gas flow them you get more flow but you are doing so by reducing the swirl and turbulance in the port and the fuel air mixes less well and although you get more mixture in it doesn't burn as well and your gains are reduced.
Open the valve fully and make the ports work more by using more revs and you get the flow AND the turbulance back so you get good cylinder filling and the turbulant mixing.
You need duration and lift with big flow heads as your heads are working best at high lift figures, unless you can get the valves open quickly hence roller tappets where the opening and closing ramps are very agressive.
(or go 4 valves per cylinder again for the same reason)
This leads to the business of generally having small port heads with a mild cam or in the case of the LS chevy engines big high flow ports and a short duration cam with roller rockers and light weight rockers valves and push rods.
If you are going to stick with those heads (which I would) then use the fuel injection hardware but with a decent controler (forget the hotwire controller it is a bodge on this set up) don't buy a hotwire AFM but use the trumpets etc and go for 225 ish of duration inlet and exhaust with as much lift as you can get with solid lifters and aftermarket lifters. Get a grind on an LSA of 112 or even 114 degrees and I think it will idle nicely, give you buckets of midrange and rev to 6000, with the right controller you should be able to do most of the mapping just driving around.
If you want to talk it over then send me a PM, I'll then send you a phone number to call me on. Sorry everything in a performance engine effects everything else, but it also isn't complicated when you look at the engine as a whole.
Best regards
Mike
there are two duration numbers quoted , the .05 (shorter one ) is the one to use, it enables you to compare durations of differnt cams using different types of lifters, the "advertised duration" is taken at .006", on a solid tappet cam the tappet clearance isn't even taken up while the Hydraulic tappet may just start lifting at .05 both types of cams should be lifting similar amounts (remember the oil in a hydraulic cam will compress a very small amount ).
Fuller explanations of cam specs can be forun on compcams website or on Iskey cams website.
High ratio rockers can be found, the buick V6 was started as a buick V8 with 2 cylinders cut off and that has been extensivly developed in the US, try looking at Yella terra they do roller rockers for the rover, I think some volvo ones can be used as high ratio rockers on a rover shaft.
Mopar engines have shaft mounted rockers similar to the rover and may be a start.
As far as the injection is concerned you have the bits you want for this set up and have not commited to a controler, the cam RS are recomending is based on the extreamly limited controler that this set up usually uses and the way you have to bodge it to work with any alterations you make to the engine, with the added restriction of the hotwire AFM. Get an aftermarket controler (VEMS, MS extra or Emerald or one of the many others) and the world is your lobster cam choice opens up because with the mapable contrloer you can actually get it to work with the mods.
If you are now only aiming at 5500 to 6000 revs then a 220 or even a 215 duration cam at .05 may be enough, if you can get the lift, however it will be a bit of a compromise unless you go for a roller lifter set up.
The choice of heads you have made really commits you to higher duration as does the larger capacity.
A bit of explanation
If you look at the flow charts for the 215 heads and the and the ford heads you will see the 215 heads at .2 of lift beat the ford heads even though at .6 lift the fords beat them hands down. Although it isn't always the case generally smaller port heads work better flow wise at lower lift. further with less timing on the cam you actually get alot of the eficiency (and power)of the engine from swirl created in the inlet port thoroughly mixing the fuel air mixture, use bigger ports and then gas flow them you get more flow but you are doing so by reducing the swirl and turbulance in the port and the fuel air mixes less well and although you get more mixture in it doesn't burn as well and your gains are reduced.
Open the valve fully and make the ports work more by using more revs and you get the flow AND the turbulance back so you get good cylinder filling and the turbulant mixing.
You need duration and lift with big flow heads as your heads are working best at high lift figures, unless you can get the valves open quickly hence roller tappets where the opening and closing ramps are very agressive.
(or go 4 valves per cylinder again for the same reason)
This leads to the business of generally having small port heads with a mild cam or in the case of the LS chevy engines big high flow ports and a short duration cam with roller rockers and light weight rockers valves and push rods.
If you are going to stick with those heads (which I would) then use the fuel injection hardware but with a decent controler (forget the hotwire controller it is a bodge on this set up) don't buy a hotwire AFM but use the trumpets etc and go for 225 ish of duration inlet and exhaust with as much lift as you can get with solid lifters and aftermarket lifters. Get a grind on an LSA of 112 or even 114 degrees and I think it will idle nicely, give you buckets of midrange and rev to 6000, with the right controller you should be able to do most of the mapping just driving around.
If you want to talk it over then send me a PM, I'll then send you a phone number to call me on. Sorry everything in a performance engine effects everything else, but it also isn't complicated when you look at the engine as a whole.
Best regards
Mike
poppet valves rule!
