Dropping in a set of RS or DC21/22 cams - info and cams needed?
02-16-2011, 06:52 PM
#16
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Thread Starter
Hi MarinS4. Noted the stock DC21 has cam lobe seperation angle of 112. Interesting about the RS inlet and GT2 exhaust profile. It sounds like you had you existing cams ground. Did you end up with a different speration angle - 115?
Thanks M
Thanks M
02-16-2011, 09:11 PM
#17
Rennlist Member
Yes I went with the stock 115 lobe separation angle to keep the torque curve broad and flat. This also helped keep overlap down for a better idle. One of the reasons I did this was to compliment the VRAM and to spread out peak cylinder pressure due to mechanical limits.
John can grind the lobe separation angle to your specs. All other specs being equal wide separation angle gives better idle, flatter torque curve and more top end power. Narrow lobe separation angle gives you a higher peak torque but not as flat. Poorer idle due to more overlap and earlier peak HP.
For the standard intake manifold you can do a 113-114 lobe separation and still be happy.
Check with John I am sure he will say pretty much the same thing I am. No need to tear into the motor for intake valves. Valve springs would be a great idea though given the age of the motor. I would also suggest converting the rockers to solids. Adjustments every 10k is really not a big deal. Those expensive factory hydraulic rockers got to be getting tired.
John can grind the lobe separation angle to your specs. All other specs being equal wide separation angle gives better idle, flatter torque curve and more top end power. Narrow lobe separation angle gives you a higher peak torque but not as flat. Poorer idle due to more overlap and earlier peak HP.
For the standard intake manifold you can do a 113-114 lobe separation and still be happy.
Check with John I am sure he will say pretty much the same thing I am. No need to tear into the motor for intake valves. Valve springs would be a great idea though given the age of the motor. I would also suggest converting the rockers to solids. Adjustments every 10k is really not a big deal. Those expensive factory hydraulic rockers got to be getting tired.
Last edited by MarinS4; 02-16-2011 at 09:36 PM.
02-16-2011, 09:48 PM
#18
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Thread Starter
Thanks Marin. Again thats usefull information. I see the DC22 has a 113 degree seperation. I guess that cam could also be an option but mya be lumpier. Once john cotacts me I will ask him the best solution for non varioram 993 and my application. I suspect I will not beable to go the regrind due to istance and time so will likely buy a fresh set off the shelf...
If I change the valve springs should I stick with stock or use heavier duty ones (I am not changing max rpm). If I stick with standard ones should I levae the valve retainer alone if they look ok? If I go stronger soring do I need new valve retainer?
Sorry for the 100 questions.
Lastly - any idea on which specific gaskets or o rings I need it only taking the top of to do the cams?
Cheers
M
If I change the valve springs should I stick with stock or use heavier duty ones (I am not changing max rpm). If I stick with standard ones should I levae the valve retainer alone if they look ok? If I go stronger soring do I need new valve retainer?
Sorry for the 100 questions.
Lastly - any idea on which specific gaskets or o rings I need it only taking the top of to do the cams?
Cheers
M
02-16-2011, 10:00 PM
#19
Rennlist Member
John may have cores that he can do an exchange on. Best to call (or e-mail) and ask.
Prior to making a choice I spoke to one of John's clients who loves the DC22 cams. He even uses it on the VRAM cars.
Upgraded valve springs are not needed but very welcome. They are not very expensive.
Once again I defer your all of questions to John. He really is the expert on the topic.
Prior to making a choice I spoke to one of John's clients who loves the DC22 cams. He even uses it on the VRAM cars.
Upgraded valve springs are not needed but very welcome. They are not very expensive.
Once again I defer your all of questions to John. He really is the expert on the topic.
02-16-2011, 10:58 PM
#20
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Thread Starter
Thanks mate. Will indeed talk with John. Sounds like the DC21 DC22 grooved for hydraullic lifters are the way to go. Overall very positive feedback. Thanks again....
M
M
02-16-2011, 11:59 PM
#21
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Thread Starter
MarinS4 or others. Do you recall how many hour labour you paid to have new cams only dropped in and timing done? Mechanic is quoting me approx 30 hrs plus a tonne of gaskets! Yikes. If hes correct then at his rate this isnt a cost effective 10hp/10lbft for me :-(
02-17-2011, 12:36 AM
#22
Rennlist Member
I had mine done when the motor was apart. I don't think the labor to rebuild my motor was much more than 30 hours. That seems very high for a cam change. 30hours is almost 4 days of work. IMHO 16-20 hours sounds about right.
02-17-2011, 01:01 AM
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02-17-2011, 01:04 AM
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Good to know you are doing the cams. Lets share notes. Why not consider the solid lifters? I am going solid.
02-17-2011, 03:38 AM
#25
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Hi Camlob. Im actually watching your install and feedback first LOL! If the labour is more like 16 hours I will proceed - otherwise this falls into the "beyond economical return" for me....
As an aside Id like to know how long the job takes for you at the end of the month?
I had long discussions with Steve Wiener on this last year. The most effective way to do this is to have my heads removed with cams and sent to his shop in US. The would then check the components, install new inlet valves 51.5mm (RS), springs, guides and retainers. He will seat the new valve and flow test the heads making some small improvements in his shop and bolt together and send back. He will replace any exhaust valves that need replacing. He recommends a Viton gasket set and ARP bolts and redurbishing the rockers. Steve recommends leaving the hydraullic system in for a street car (otherwise add $1400usd). Given a free flow exhaust (no cats Dach X and RSR mufflers) I could expect 12-15bhp/15lbft improvements with peak figures in the 5500-6500 rpm band and no more than 6800 rpm red line unless bottom end modifications are made.
The above is what I believe e3photo is having done and it is the ultimate solution as the inlet valves on the non varioram engines uessentially limit the benefits of the cams especially with a free flowing exhaust (such as your headers). The physics dictate I guess that although you can advance timing and match with more aggressive cam lobes you need to allow air to enter and exit the chambers more efficently otherwise essentially there will be abottle neck or weakest link (i.e. inlet valve size, manifold design or air intake system and conversely exhaust valve size, headers and catalytic converters).
However - my logic is that this car is for weekend driving pleasure and long touring. Its neever going to be a GT3 with 8500 rpm revline making 350bhp+ without spending 30k usd and some significnat compromises.
What I have learnt to date is that for every significant modification to the 993 comes some form of compromise. To this day I have been very luck to have an engine that has responded well to light modification (syno plots sho its one of te stronger engines on this board) while travelling well over rough pavement, handling well and not stalling (I have RS LWFC on 1994 993). I have had my fingers crossed at each modification and luckily escaped to date with no ill effects to pratciality and driving pleasure at all. The car runs beautifully cold or hot, high rpm or low - even my wife can hop in and drive it same as always.
So, when contemplating putting in an LSD (still not convinced i will do this), I thought - heck while the engine is out (again second time in 15 months as RSLWFC was done last Feb) I might look at costs around dropping in simply a pair of cams. Nothing more, nothing less assuming of course my top end is still in nice condition after 17 years and 72k km. Reading back through my notes it appears that it is possible I could just open it up, drop in some grooved cams for RS, DC21 or DC22 to be used with the hydraullic rockers, add new gaskets and close her up. Ive been told by Steve this solution should see maybe 8-10bhp/10lbft on my engine. As long as the cams are not too aggressive I can leave my idle where it is at 880rpm (lifted slightly already by Steve Wong for RSLWFC) and enjoy a vehicle that isnt too lunmpy at idle or stall/mis behave will having a slightly higher output in a similar Rpm range where I currently make peak power and torque. Essentially with my existing intake and exhaust mods and overall upgrades, replacements and refurbishments of other key components over the last 12 months this should make the engine good for 300bhp and 265lbft (about what the 1994 Cup cars made and similar to my old RS - although that car made less than quoted hp for some reason...). Again, the above would be accompanies by a new custom mapped chip from Steve Wong (I already have one from existing set up) based on AFR traces emailed to him from my Dtyno operator (I use the same operator and dyno on this care over the last few years)...
Assuming a new set of cams is $1000 usd, gasket set $400 usd and labour is say $1000 usd I figured that was a pretty reasonable return which would keep me happy for the next 50k km or 8-10 years at which time should something necessitate a top end overhaul I can then send the heads off to Steve to rebuild for almost no additional cost over what i would have to spend locally.
That was my logic. The key with keeping the Hydraullic cams was reduction in cost ($1400 usd approx), reduction in furture labour (significant every 15-20,000 km as potentially the negine needs to be dropped) and to ensure a modifcation route that does not spoil the driving experience. Yes solid rockers with mechanical adjustment will make a fraction more power and are more reliable at sustained high rpm as experienced on agressive track days or for a racing car (hydraullic system is known to "pump down" the rockers at extended 7000 rpm + runs) - but the reality is this car only see regular hi rpm when I go for a weekend drive on backroads - and not for extended periods of time.
Ive been really well rewarded over the years researching everything well before going ahead with it and talking with others who have been down a particular path. Although there are a few mods I would never have bothered performing if I had have known the cost and time involved for seemingly small improvements (see my one of my past threads) I can honestly say that if money were no object i would do it all again - nothing I have done to the vehicle has had a significant down side to date. I really dont want to jump into stuff and come out with a big dissapointment - a car that stalls or wont run when cold properly or which is really compmoised and looses its fun.
My original 2011/2012 plan was to go the full 9M stage 2 route. After 6 months of reserach and a bit o soul searching I decided to push the 993 no further power wise and enjoy it for what it is putting that spend into my future 997.2 GT3. However your recent thread regards doing the cams got me thinking there may still be a way to achieve a nice round outcome for lower cost. esstentially 300 bhp for 1300 kg and 265-270lbft torque has been my ultimate final goal for the 993 for quite some time now. I thought I had reached as far as I could go after the last round of work and dyno but you got me thnking and resarching again and going back through past correspndence and notes. I now believe its possible to achieve this and if it can be done for circa $2500 usd all up for a set of DC21 or DC22 grooved for Hydraulic lifters and the gods are with me with the condition of my existing valve train then I will do this without from what I have been told by almost everyone any real compromise to driveablilty. I should also Ive been led to believe fairly comfortably meet my hp/lbft targets. All good.
Thats the plan but Im still researching and the instllation of your DC24 cams with I assume solid lifters and your new headers (nice) will be another data point I wouldlike to learn from....
Hurry up and do it :-)
Cheers
M
As an aside Id like to know how long the job takes for you at the end of the month?
I had long discussions with Steve Wiener on this last year. The most effective way to do this is to have my heads removed with cams and sent to his shop in US. The would then check the components, install new inlet valves 51.5mm (RS), springs, guides and retainers. He will seat the new valve and flow test the heads making some small improvements in his shop and bolt together and send back. He will replace any exhaust valves that need replacing. He recommends a Viton gasket set and ARP bolts and redurbishing the rockers. Steve recommends leaving the hydraullic system in for a street car (otherwise add $1400usd). Given a free flow exhaust (no cats Dach X and RSR mufflers) I could expect 12-15bhp/15lbft improvements with peak figures in the 5500-6500 rpm band and no more than 6800 rpm red line unless bottom end modifications are made.
The above is what I believe e3photo is having done and it is the ultimate solution as the inlet valves on the non varioram engines uessentially limit the benefits of the cams especially with a free flowing exhaust (such as your headers). The physics dictate I guess that although you can advance timing and match with more aggressive cam lobes you need to allow air to enter and exit the chambers more efficently otherwise essentially there will be abottle neck or weakest link (i.e. inlet valve size, manifold design or air intake system and conversely exhaust valve size, headers and catalytic converters).
However - my logic is that this car is for weekend driving pleasure and long touring. Its neever going to be a GT3 with 8500 rpm revline making 350bhp+ without spending 30k usd and some significnat compromises.
What I have learnt to date is that for every significant modification to the 993 comes some form of compromise. To this day I have been very luck to have an engine that has responded well to light modification (syno plots sho its one of te stronger engines on this board) while travelling well over rough pavement, handling well and not stalling (I have RS LWFC on 1994 993). I have had my fingers crossed at each modification and luckily escaped to date with no ill effects to pratciality and driving pleasure at all. The car runs beautifully cold or hot, high rpm or low - even my wife can hop in and drive it same as always.
So, when contemplating putting in an LSD (still not convinced i will do this), I thought - heck while the engine is out (again second time in 15 months as RSLWFC was done last Feb) I might look at costs around dropping in simply a pair of cams. Nothing more, nothing less assuming of course my top end is still in nice condition after 17 years and 72k km. Reading back through my notes it appears that it is possible I could just open it up, drop in some grooved cams for RS, DC21 or DC22 to be used with the hydraullic rockers, add new gaskets and close her up. Ive been told by Steve this solution should see maybe 8-10bhp/10lbft on my engine. As long as the cams are not too aggressive I can leave my idle where it is at 880rpm (lifted slightly already by Steve Wong for RSLWFC) and enjoy a vehicle that isnt too lunmpy at idle or stall/mis behave will having a slightly higher output in a similar Rpm range where I currently make peak power and torque. Essentially with my existing intake and exhaust mods and overall upgrades, replacements and refurbishments of other key components over the last 12 months this should make the engine good for 300bhp and 265lbft (about what the 1994 Cup cars made and similar to my old RS - although that car made less than quoted hp for some reason...). Again, the above would be accompanies by a new custom mapped chip from Steve Wong (I already have one from existing set up) based on AFR traces emailed to him from my Dtyno operator (I use the same operator and dyno on this care over the last few years)...
Assuming a new set of cams is $1000 usd, gasket set $400 usd and labour is say $1000 usd I figured that was a pretty reasonable return which would keep me happy for the next 50k km or 8-10 years at which time should something necessitate a top end overhaul I can then send the heads off to Steve to rebuild for almost no additional cost over what i would have to spend locally.
That was my logic. The key with keeping the Hydraullic cams was reduction in cost ($1400 usd approx), reduction in furture labour (significant every 15-20,000 km as potentially the negine needs to be dropped) and to ensure a modifcation route that does not spoil the driving experience. Yes solid rockers with mechanical adjustment will make a fraction more power and are more reliable at sustained high rpm as experienced on agressive track days or for a racing car (hydraullic system is known to "pump down" the rockers at extended 7000 rpm + runs) - but the reality is this car only see regular hi rpm when I go for a weekend drive on backroads - and not for extended periods of time.
Ive been really well rewarded over the years researching everything well before going ahead with it and talking with others who have been down a particular path. Although there are a few mods I would never have bothered performing if I had have known the cost and time involved for seemingly small improvements (see my one of my past threads) I can honestly say that if money were no object i would do it all again - nothing I have done to the vehicle has had a significant down side to date. I really dont want to jump into stuff and come out with a big dissapointment - a car that stalls or wont run when cold properly or which is really compmoised and looses its fun.
My original 2011/2012 plan was to go the full 9M stage 2 route. After 6 months of reserach and a bit o soul searching I decided to push the 993 no further power wise and enjoy it for what it is putting that spend into my future 997.2 GT3. However your recent thread regards doing the cams got me thinking there may still be a way to achieve a nice round outcome for lower cost. esstentially 300 bhp for 1300 kg and 265-270lbft torque has been my ultimate final goal for the 993 for quite some time now. I thought I had reached as far as I could go after the last round of work and dyno but you got me thnking and resarching again and going back through past correspndence and notes. I now believe its possible to achieve this and if it can be done for circa $2500 usd all up for a set of DC21 or DC22 grooved for Hydraulic lifters and the gods are with me with the condition of my existing valve train then I will do this without from what I have been told by almost everyone any real compromise to driveablilty. I should also Ive been led to believe fairly comfortably meet my hp/lbft targets. All good.
Thats the plan but Im still researching and the instllation of your DC24 cams with I assume solid lifters and your new headers (nice) will be another data point I wouldlike to learn from....
Hurry up and do it :-)
Cheers
M
02-17-2011, 07:57 AM
#26
JMO, but if you aren't going to throw cubic dollars at it and want a satisfying street engine, keep the hyd. lifters, use RS cams and head configuration, use Arp or Raceware rod bolts, a chip and RS rev limit, even more satisfying for street use is more displacement but then that's getting expensive,
A stock 3.6 built as above will be seeing close to 300hp, right Mike?
A stock 3.6 built as above will be seeing close to 300hp, right Mike?
02-17-2011, 03:35 PM
#28
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Thread Starter
Hi Bill. I think you are right hence my original post was titled does anyone have any (RS) cams for sale. I changed it when the subject started to broaden LOL!
I tghink essentially I will stick to the plan of RS or DC21 cams for hydrallic lifters, do the arp bolts (not expensive), bump the rpm to 6800-6900 and have the chip optimised on the dyno. If that gets me the desired outcome Ill be a really happy man...
Camlob. Do you have the specific gasket part numbers for this job available to share with usall here or did you just end up buying teh entire gasket kit for $400+?
Cheers
M
I tghink essentially I will stick to the plan of RS or DC21 cams for hydrallic lifters, do the arp bolts (not expensive), bump the rpm to 6800-6900 and have the chip optimised on the dyno. If that gets me the desired outcome Ill be a really happy man...
Camlob. Do you have the specific gasket part numbers for this job available to share with usall here or did you just end up buying teh entire gasket kit for $400+?
Cheers
M
02-17-2011, 06:45 PM
#29
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Hi Bill. I think you are right hence my original post was titled does anyone have any (RS) cams for sale. I changed it when the subject started to broaden LOL!
I tghink essentially I will stick to the plan of RS or DC21 cams for hydrallic lifters, do the arp bolts (not expensive), bump the rpm to 6800-6900 and have the chip optimised on the dyno. If that gets me the desired outcome Ill be a really happy man...
Camlob. Do you have the specific gasket part numbers for this job available to share with usall here or did you just end up buying teh entire gasket kit for $400+?
Cheers
M
I tghink essentially I will stick to the plan of RS or DC21 cams for hydrallic lifters, do the arp bolts (not expensive), bump the rpm to 6800-6900 and have the chip optimised on the dyno. If that gets me the desired outcome Ill be a really happy man...
Camlob. Do you have the specific gasket part numbers for this job available to share with usall here or did you just end up buying teh entire gasket kit for $400+?
Cheers
M
So if I were you, get the complete head gasket set so you can rest assured that everything is there.
http://www.pelicanparts.com/cgi-bin/...FILTER_TOOL=ON
http://www.pelicanparts.com/cgi-bin/...94),%20Each%20
02-17-2011, 09:14 PM
#30
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Thread Starter
Thanks Camlob. I will look into that. Like yourself wasnt keen on paying $450 usd on a full set when I only need the smaller ones but looks like it may be the only way. Im quite suprised someone hasnt listed the specific gaskets and they dont have a part number form the OEM supplier to Porsche that they could be acquired using. I have not found such a list yet on searching Rennlist but your Pelican links are as close as I have seen....
John D has come back to me and to use DC21 which he recommends for my application it looks like indeed I need to go for solid rockers. Looks like I cant use hydraullic. However his pricng on teh solid lifters seems resonable. Mmmm. It started out looking lik a good bang for buck mod at this level now the slow is slippeery again LOL!
M
John D has come back to me and to use DC21 which he recommends for my application it looks like indeed I need to go for solid rockers. Looks like I cant use hydraullic. However his pricng on teh solid lifters seems resonable. Mmmm. It started out looking lik a good bang for buck mod at this level now the slow is slippeery again LOL!
M