Hi all,
I would greatly appreciate your thoughts & experiences (and preferences) on the great debate between hydraulic & solid cams. My 383 SBC currently has a hydraulic in it, and I've always been pretty happy with it, but I have noticed it's never been the most vicious; or 'sharp' engine (perhaps a trait of hydraulics?).
Engine is currently going through a rebuild, so it's the perfect time to change to a solid (mechanical flat tappet) if I so decide.
What are the pro's and con's of each?
What do you guys run and WHY?
What effects does each have in terms of fuel economy? How about engine response, power & torque, driveability???
Any thoughts and feedback will be all taken into consideration and muchly appreciated.
Thanks,
Brett.
Hydraulic vs Solid Cam
Started by
LXCHEV
, Feb 14 2006 09:43 AM
28 replies to this topic
#1
LXCHEV
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Posted 14 February 2006 - 09:43 AM
#2
makka
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Posted 14 February 2006 - 10:14 AM
about all I can add is that solids sound tough!
#3
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Posted 14 February 2006 - 12:50 PM
I have a roller(not flat tappet) solid in mine, i believe that a solid can rev higher, 6500 i have heard is max for a hydraulic not that its a problem for you coz with 383ci why rev any harder. I think mine needed a solid because it was going to 7500rpm when raced.
With a solid you also need to adjust them every 6months or so, which is a pain for me coz i got all the gas setup sitting over my valve covers, so it all has to come off to get to them!
This is just what i heard sure that others in here know more....
With a solid you also need to adjust them every 6months or so, which is a pain for me coz i got all the gas setup sitting over my valve covers, so it all has to come off to get to them!
This is just what i heard sure that others in here know more....
#4
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Posted 14 February 2006 - 02:17 PM
theres a little more maintenance with a solid cam compared to a hyd. Valve last needs to be adjusted regularly.
Solid and hyd are very similar one uses a solid lifter the other uses a lifter cushioned with oil to take up the slack from wear and tear. My opinion is that a solid cam is better as you dont get pump up in your lifters like you do with a hyd and as a result you get more precise valve lift.
i think it also comes down to what sort of engine you want to build, eg level of power/torque and how hard you want to rev it.
A roller cam would be the ultimate, less wear and tear, you can run big lift cams with aggressive ramp ups and make lots more hp/tq without using radical grinds. But the down side is $$$ as its a far more expensive exercise than a hyd/solid.
Im using a solid cam in my 355 stroker due to the fact that im on a budget otherwise i would have gone roller.
Solid and hyd are very similar one uses a solid lifter the other uses a lifter cushioned with oil to take up the slack from wear and tear. My opinion is that a solid cam is better as you dont get pump up in your lifters like you do with a hyd and as a result you get more precise valve lift.
i think it also comes down to what sort of engine you want to build, eg level of power/torque and how hard you want to rev it.
A roller cam would be the ultimate, less wear and tear, you can run big lift cams with aggressive ramp ups and make lots more hp/tq without using radical grinds. But the down side is $$$ as its a far more expensive exercise than a hyd/solid.
Im using a solid cam in my 355 stroker due to the fact that im on a budget otherwise i would have gone roller.
Edited by 355lxss, 14 February 2006 - 02:24 PM.
#5
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Posted 14 February 2006 - 02:26 PM
I been wanting to know the answer to this for quite some time now.. All i know is a mate with a HQ 350 SBC was running a very big Hydrolic cam and the car used to run 12.7 ETs, all he changed was his cam to a 2nd design solid and hi-stall from 3000rpm to 4000rpm and the car ran low 11s and 10.8 on NOS... So obviuosly it made much more power...
John
John
#6
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Posted 14 February 2006 - 02:42 PM
hydraulic anti pump up lifters?My opinion is that a solid cam is better as you dont get pump up in your lifters like you do with a hyd and as a result you get more precise valve lift.
#7
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Posted 14 February 2006 - 04:01 PM
didnt think their still suitable for high revving applications say to around 7500rpm? could be wrong? Still think a solid would be more relaibe at high rpm's.hydraulic anti pump up lifters?My opinion is that a solid cam is better as you dont get pump up in your lifters like you do with a hyd and as a result you get more precise valve lift.
#8
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Posted 14 February 2006 - 04:51 PM
From what I understand solid cam by definition refers more to the lifters than the cam itself. As 355lxss has said the lifter is a round barrel of metal with fixed base and pushrod cup. Valve lash is supposed to be measured regularily and accurately to minimise the valve lash and free play in the whole valve/rocker etc. assembly. They are noisy, have a shorter lifespan and are mostly intended for comp use from what I can understand.
And I absolutely love my solid cam and wouldn't go back to a hydraulic. Roller cam is un-necessary IMO for a part time drag car because the solid does give excellant valve response. Sounds great, gives great performance and who cares about a little bit of effort every now and then, especially for the amount of time you will be driving it LXCHEV. It would make your motor a serious, serious piece of equipment. But you're not allowed to get bigger lift than me o.k.
Cheers,
And I absolutely love my solid cam and wouldn't go back to a hydraulic. Roller cam is un-necessary IMO for a part time drag car because the solid does give excellant valve response. Sounds great, gives great performance and who cares about a little bit of effort every now and then, especially for the amount of time you will be driving it LXCHEV. It would make your motor a serious, serious piece of equipment. But you're not allowed to get bigger lift than me o.k.
Cheers,
#9
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Posted 14 February 2006 - 05:08 PM
Great info here, Solid, and hydraulic, is there a way to identify a camshaft?, Also i am interested in how one would ajust solid lifters.
#10
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Posted 14 February 2006 - 07:41 PM
hey gstar im not sure about telling the difference between the two actual cam shafts but the solid lifter set up is adjusted on the rockers,
im just about at the end of my engine rebuild now actaully and i went for the 282 solid crow cam i cant wait to see how thatll go after the feed back u guys hav been giving!
im just about at the end of my engine rebuild now actaully and i went for the 282 solid crow cam i cant wait to see how thatll go after the feed back u guys hav been giving!
#11
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Posted 14 February 2006 - 08:26 PM
Brett for your 383, I would stick with a hydraulic cam. Mainly because the solids have the advantage at higher revs, which your stroker simply won't rev to. If you start seeing the other side of 7000 RPM, by all means use a solid, or even better a roller cam.
#12
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Posted 14 February 2006 - 08:35 PM
Just out of interest any one got a ruff figure how much you should pay to have someone adjust a solid cam???? how many hours it should take??
cheers
cheers
Edited by LhMusL, 14 February 2006 - 08:36 PM.
#13
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Posted 14 February 2006 - 08:41 PM
A six should be adjusted in less than an hour. A V8 could take a while if the rocker covers are buggers to get off.
#14
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Posted 15 February 2006 - 12:10 AM
It takes me about an hour to run through them 2 times I m pretty fussy with my consistancee with my shim drag on the roller , half an hour to get to them and half an hourish to clean an put everything back , while having a beer standing between the thermo fans and engine.
Depending how hard you drive or what you do with the engine ,I tend to adjust my valves every 1000 to 2000 km.
As a solid cam my is not a daily driver...
I m a heavy diesel mechanic by trade but anyone can adjust valves , it not hard just fiddley , you ll get a nack for it ...
Just be carefull if you get a mechanical place to do it ,
some charge hard for fast stuff...
Depending how hard you drive or what you do with the engine ,I tend to adjust my valves every 1000 to 2000 km.
As a solid cam my is not a daily driver...
I m a heavy diesel mechanic by trade but anyone can adjust valves , it not hard just fiddley , you ll get a nack for it ...
Just be carefull if you get a mechanical place to do it ,
some charge hard for fast stuff...
#15
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Posted 15 February 2006 - 06:41 AM
Roller is the tappet design, they either come in roller, flat tappet or mushroom tappet (extinct).A roller cam would be the ultimate, less wear and tear, you can run big lift cams with aggressive ramp ups and make lots more hp/tq without using radical grinds. But the down side is $$$ as its a far more expensive exercise than a hyd/solid.
The ultimate is a Solid roller camshaft, but operation is the same for a flat tappet or roller tappet, being mechanical you will still need to adjust lash, it is critical.
If your lazy dont go mechanical, stick with hydraulic.
If you dont mind adjusting lash once a month or eevry 2,000kms then go mechanical.
If it were me in your shoes I would stick with hydraulic due to the fact your 383 probably runs out of puff at 6,000rpm anyway, makes peak around 5,500?
But if you do go mechanical camshaft make sure its an easy maintenance exercise, eg you dont need to take the brake booster out every time to get to the rocker covers etc. If its a pain in the ass to work on it will only deter you away from it.
#16
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Posted 15 February 2006 - 07:32 AM
Is there anything to be gained by running solid lifters on a (hot) hydraulic cam ?
#17
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Posted 15 February 2006 - 08:46 AM
There used to be saying, "solid cams are for race cars, hydraulic cams are for tow cars".
A hydraulic is pretty much set and forget. They are quiet and maintenance free. A solid however will usually generate more torque than an equivalent hyd. due to its ability to have a more aggressive lobe design. Hyd. cams are not just RPM limited. As the lifter attempts to open the valve any hyd. lifter is going to bleed off slightly, slowing down the valve opening event. With a solid there is no cushioning effect and the valve can be ripped open a considerable amount faster, thereby creating more area under the valve lift graph and therefore more torque.
As far as valve adjustments go..... if you tighten the rockers correctly and don't have cam/lifter wear issues how will your lash change ? It is a good idea to check it regularly though, in case some cam/lifter and valve/seat wear is experienced. I recently checked my lash for the first time since the engine was assembled (about 18months ago) it hadn't changed significantly.
Personally, any engine that gets more race work than street work deserves a solid cam, unless you don't want to or are too lazy to check lash. These days there are some hyd. cams out there that have a lot of "intensity". This creates a hyd. that acts more like a solid in that its valve opening rate is very fast and on the edge of what a hyd. lifter can cope with. The down side is rapid cam/lifter wear and excessive valve train noise. It would pay to avoid these grinds.
As for rollers....I haven't used one for years. They are expensive and the lifters and springs are expensive. Yes they work OK and they do have their place in max effort race engines but I personally can't see the value. If you can't make 1.75HP/CID with a solid cam then your not trying. Also they don't float valves due to the enormous spring loads. Miss a gear or break traction and your engine will rev to the moon, usually damaging something else rather than merely floating the valves for a split sec.
This is a trick used in race classes that have a control hyd. cam. I know that AUSCAR 308's had a mild Speed Pro hyd. control cam and most teams used it with solid lifters to get the max from the lobes. It was only worth about 6Hp or less than 1.5%. It would have been worth more with a more aggressive profile (the Speed Pro was a pretty pedestrian design, designed to last forever and be quiet). Basically, if you want a solid cam buy one, if you dont, buy a hydraulic.
Once again these are just my personal opinions.
A hydraulic is pretty much set and forget. They are quiet and maintenance free. A solid however will usually generate more torque than an equivalent hyd. due to its ability to have a more aggressive lobe design. Hyd. cams are not just RPM limited. As the lifter attempts to open the valve any hyd. lifter is going to bleed off slightly, slowing down the valve opening event. With a solid there is no cushioning effect and the valve can be ripped open a considerable amount faster, thereby creating more area under the valve lift graph and therefore more torque.
As far as valve adjustments go..... if you tighten the rockers correctly and don't have cam/lifter wear issues how will your lash change ? It is a good idea to check it regularly though, in case some cam/lifter and valve/seat wear is experienced. I recently checked my lash for the first time since the engine was assembled (about 18months ago) it hadn't changed significantly.
Personally, any engine that gets more race work than street work deserves a solid cam, unless you don't want to or are too lazy to check lash. These days there are some hyd. cams out there that have a lot of "intensity". This creates a hyd. that acts more like a solid in that its valve opening rate is very fast and on the edge of what a hyd. lifter can cope with. The down side is rapid cam/lifter wear and excessive valve train noise. It would pay to avoid these grinds.
As for rollers....I haven't used one for years. They are expensive and the lifters and springs are expensive. Yes they work OK and they do have their place in max effort race engines but I personally can't see the value. If you can't make 1.75HP/CID with a solid cam then your not trying. Also they don't float valves due to the enormous spring loads. Miss a gear or break traction and your engine will rev to the moon, usually damaging something else rather than merely floating the valves for a split sec.
Is there anything to be gained by running solid lifters on a (hot) hydraulic cam ?
This is a trick used in race classes that have a control hyd. cam. I know that AUSCAR 308's had a mild Speed Pro hyd. control cam and most teams used it with solid lifters to get the max from the lobes. It was only worth about 6Hp or less than 1.5%. It would have been worth more with a more aggressive profile (the Speed Pro was a pretty pedestrian design, designed to last forever and be quiet). Basically, if you want a solid cam buy one, if you dont, buy a hydraulic.
Once again these are just my personal opinions.
#18
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Posted 15 February 2006 - 06:51 PM
i agree with everything above. i have seen a lot of solid lifters used on hydro cams...is good for wearing everything very quickly. i'm gonna go solid on my next engine build cause i hate adjusting hydro cams....they annoy me. get oil everywhere. atleats a solid cam you adjust with the motor not running.
#19
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Posted 15 February 2006 - 06:58 PM
Brett can you give me a run down on the complete package? Not just engine but driveline as well.
Everyone has pretty much covered most aspects of hyd vs solid, one thing you should keep in mind is your current vavle train. A hydraulic cam can't run more than approx 120-130lb on seat, overwise the lifters will bleed down when the engine is stopped/idling. A solid flat tappet cam, with its faster opening and closing ramps requires a heavier spring...
People who say a solid only makes more power up high aren't correct, by utilising the fast opening rates cam grinders have less comprimises than with a hydraulic cam. So it is possible to have a larger cam in regards to lift and duration at 0.050" that has less overlap and better torque than an equivalent hydraulic.
Roller followers cannot be allowed to float at all, which combined with the hugely aggressive ramps found on a roller cam explains the need for such massive spring pressures.
If it was my engine I'd run with a solid, a cam that we've used in the past in a 383, fitted to an HG Brougham is the Comp Cams XS282S, part number 12-678-4. That ran 11.80 at 112 mph with 3.7 gears 3300 stall and Ultimate 98 octane. Max power was approx 6200, and with some lower gears it would have performed even better.
Everyone has pretty much covered most aspects of hyd vs solid, one thing you should keep in mind is your current vavle train. A hydraulic cam can't run more than approx 120-130lb on seat, overwise the lifters will bleed down when the engine is stopped/idling. A solid flat tappet cam, with its faster opening and closing ramps requires a heavier spring...
People who say a solid only makes more power up high aren't correct, by utilising the fast opening rates cam grinders have less comprimises than with a hydraulic cam. So it is possible to have a larger cam in regards to lift and duration at 0.050" that has less overlap and better torque than an equivalent hydraulic.
Roller followers cannot be allowed to float at all, which combined with the hugely aggressive ramps found on a roller cam explains the need for such massive spring pressures.
If it was my engine I'd run with a solid, a cam that we've used in the past in a 383, fitted to an HG Brougham is the Comp Cams XS282S, part number 12-678-4. That ran 11.80 at 112 mph with 3.7 gears 3300 stall and Ultimate 98 octane. Max power was approx 6200, and with some lower gears it would have performed even better.
#20
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Posted 15 February 2006 - 08:31 PM
BOTTLEDUP what cam wuld you recomend for a 5ltr EFI motor.. I have a COME racing HVH890 grind cam, lifters and valve springs.. Im only running standerd comp and the rest of the motor is stock VS with 110,000ks on it...
I basicly want a motor that has a nice lumpy note and strong as it can be with a stock EFI 65mm throttle body..Should i get a crane grind or stick to what i have and maybe up the comp by shaving theheads a little?....
I also have Blue top injectors and bosch 500HP pump...Its going in my Hatch with T350 2500rpm stall and 9" 3.55 gears..
Im ready to assemble the engine and drop it all in..
Thanks
John
I basicly want a motor that has a nice lumpy note and strong as it can be with a stock EFI 65mm throttle body..Should i get a crane grind or stick to what i have and maybe up the comp by shaving theheads a little?....
I also have Blue top injectors and bosch 500HP pump...Its going in my Hatch with T350 2500rpm stall and 9" 3.55 gears..
Im ready to assemble the engine and drop it all in..
Thanks
John
#21
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Posted 15 February 2006 - 08:55 PM
ToranaSS I think your combo ina lightweight hatch will be a great street combo, no 11 second engine but a nice streeter.
With COME racing they always specify the smallest camshaft possible for there street car enquiries, so there "stage" 1,2 etc cams are pretty small compared to other brands, but in a light car you dont need much to get them up and going, the biggest problem for your 5.0l is the rpm restricted manifold, that 304 should be able to rev and make power past 6,500rpm, but those banana's drop off power at 5,200rpm, its a miss matched combo from day dot with those efi 5.0l's.
A good manifold and T/B and gets some rpm going and it should be fun.
With COME racing they always specify the smallest camshaft possible for there street car enquiries, so there "stage" 1,2 etc cams are pretty small compared to other brands, but in a light car you dont need much to get them up and going, the biggest problem for your 5.0l is the rpm restricted manifold, that 304 should be able to rev and make power past 6,500rpm, but those banana's drop off power at 5,200rpm, its a miss matched combo from day dot with those efi 5.0l's.
A good manifold and T/B and gets some rpm going and it should be fun.
#22
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Posted 15 February 2006 - 10:44 PM
Thanks for all the great replies everyone, it's been a very informative read.
Firstly, BOTTLEDUP - Here are my basic specs: 383, 6" rods, SRP Forgies, 200cc Iron Pro Lightning heads (currently being cleaned up with a bit more work, 2.02 & 1.60), RPM Air-Gap, 825 Mighty Demon, ICE digital ignition, 10:1 comp. Rest of the driveline: TH350, 3200 hi-stall, 9" with 3.7's.
With regard to the need for frequent adjustment, that thought is not worrying me. It's a very easy 5 minute job to have both my rocker covers off, and I enjoy working on the car, so adjusting rockers every 2000 km's would be ok.
Initially, I was still leaning towards retaining the hydraulic (as Chopper and LS1LX hinted at - my engine is a low-revver, definitely runs out of puff at 6000), however I do like the fact the even at lower revs, the solid will be opening the valves harder/quicker/more precisely etc. This week I have spoken to a lot of people and they all say the same thing - solids are just RESPONSIVE! I have been talked into it.
So yes, even though this donk is not a big revver, I'm looking forward to trying a solid, there's only one way to find out for myself right! I believe it could be time to re-visit my valve springs by the sounds of what you guys have said too....
At the end of the day, I'm not driving this car anywhere near as much as I used to either, so it's time to play a bit more
Once again, thanks to everyone for posting, it has been very helpful indeed. By all means, keep the conversion going....
I will keep you updated...
Firstly, BOTTLEDUP - Here are my basic specs: 383, 6" rods, SRP Forgies, 200cc Iron Pro Lightning heads (currently being cleaned up with a bit more work, 2.02 & 1.60), RPM Air-Gap, 825 Mighty Demon, ICE digital ignition, 10:1 comp. Rest of the driveline: TH350, 3200 hi-stall, 9" with 3.7's.
With regard to the need for frequent adjustment, that thought is not worrying me. It's a very easy 5 minute job to have both my rocker covers off, and I enjoy working on the car, so adjusting rockers every 2000 km's would be ok.
Initially, I was still leaning towards retaining the hydraulic (as Chopper and LS1LX hinted at - my engine is a low-revver, definitely runs out of puff at 6000), however I do like the fact the even at lower revs, the solid will be opening the valves harder/quicker/more precisely etc. This week I have spoken to a lot of people and they all say the same thing - solids are just RESPONSIVE! I have been talked into it.
So yes, even though this donk is not a big revver, I'm looking forward to trying a solid, there's only one way to find out for myself right! I believe it could be time to re-visit my valve springs by the sounds of what you guys have said too....
At the end of the day, I'm not driving this car anywhere near as much as I used to either, so it's time to play a bit more
Once again, thanks to everyone for posting, it has been very helpful indeed. By all means, keep the conversion going....
I will keep you updated...
#23
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Posted 15 February 2006 - 10:51 PM
PS. Liam - how much lift are you running mate? (Just so I know what to aim for!!!).
By the way, I was chatting with our exhuast bloke last week, he was really impressed with your car, esp the engine. Reckons I might have some pretty tough competition!
By the way, I was chatting with our exhuast bloke last week, he was really impressed with your car, esp the engine. Reckons I might have some pretty tough competition!
#24
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Posted 16 February 2006 - 10:03 AM
Cool cool Thanks LS1LX thats what i want a nice street motor.. I spoke to the dude at COME racing when i brought the Kit off them and he reckons this kit makes good power and will work with a Supercharger without needing to replace the cam.. Id love a vorteck V1 on about 10psi
John
John
#25
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Posted 16 February 2006 - 10:03 AM
Jezus brett... wasnt an 11.7 enough! ( dont answer that.. i know the answer myself!! HAHAHA)
Mate I'm running a solid in mine and with a tight lobe centre as stuggler suggested, you can get away with a fairly decent lift cam, but retain good throttle response!!
The ONLY thing for your to consider in a torry is getting those rocker covers off frequently for a tappet check. Its easy in the HQ ( relatively) and infact i'm due for one. I do it whenever i do an oil change.. and ive done about 2000 HARD kms.. so its time!
To do it.. is pretty easy.. I do it at the workshop using some tools that my engine builder has deigned to make the locking - altering - re locking if the pozilocks a breeze, but i think i might buy myself one and the correct feeler guage myself.
I'd say go for it.. you wont look back, as long as you can get to the rockers to adjust them and remeber.. toob ig is only JUST big enough
Cheers!
Mate I'm running a solid in mine and with a tight lobe centre as stuggler suggested, you can get away with a fairly decent lift cam, but retain good throttle response!!
The ONLY thing for your to consider in a torry is getting those rocker covers off frequently for a tappet check. Its easy in the HQ ( relatively) and infact i'm due for one. I do it whenever i do an oil change.. and ive done about 2000 HARD kms.. so its time!
To do it.. is pretty easy.. I do it at the workshop using some tools that my engine builder has deigned to make the locking - altering - re locking if the pozilocks a breeze, but i think i might buy myself one and the correct feeler guage myself.
I'd say go for it.. you wont look back, as long as you can get to the rockers to adjust them and remeber.. toob ig is only JUST big enough
Cheers!
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