Question about solid valve lifters....?

[Gen1GT]

im sure that all of us out there who don't regrind cams or most all of us who didn't even know there was a difference between solid/hydraulic cams...are sorry to have you get all edgy about this....

you have to take into consideration that most people don't have a ****ing clue... you had to learn about them...so do the rest of us.

anyway... im glad you made it a point to look up the difference on a search engine...
as well as the need to familiarize ourselves with this...*otto cycle*

Otto cycle is jargon for '4 stroke'.

I'm sure Mike didn't need to seach anything on google either.

solid lifters are a solid bucket which when acted on by the cam, push down on the valve. Hydraulic lifters are a floating system, where oil-pressure pushes up on the lifter, creating a zero-tolorance at all times, and doesn't need adjustment. Solid lifters need to be shimmed to maintain the correct valve lash(the distance between the cam and the lifter), and has to be checker periodically. HLAs are zero-maintainence, but aren't as good for high RPM usage.

[jitb37]

spoon fed? lol i just asked a question and wanted an answer....everyone knows something that someone else doesnt know...gotta ask questions to learn..

I searched the forum, and ididnt find anything, so i found themans Faq...and read it and found my answer...but i had a question about that. Thanx for those who actually posted helpful info...

[mike323]

The main difference and the only difference is the first 0.010"on the cam ramps. The ramp are the slopes (how quickly or how slowly the valve opens/closes) on the cam profile.

The ramp on cams that use hydraulic lifters are quicker as opposed to the cams that use solid lifters. If I we had the same cam profile (same lift, same duration at 0.010", 0.020", 0.050", 0.100"and so on) the one that will be used in the hydraulic lifter setup will have less duration at 0.004"cam lift as opposed to the solid lifter setup.

Advertised duration is what controls your combustion pressure. Actually intake valve closing and exhaust valve opening controls your combustion pressure. If I install a solid cam profile on the HLA setup I would start loosing combustion pressure, hence loose power.

Also, all cars with solid lifter setup have a clearance of 0.006-0.008"between the cam base circle and the lifter, the reason for the clearance is in order to achieve a similar opening and closing point as the hydraulic setup. BTW the engine with the HLA setup will always create more torque at low rpms due it's ramp design.

[Gen1GT]

Oh, I see. So a solid lifter cam will have slightly more duration at a uselessly low lift, which lowers your dynamic compression ratio?

Mike, what do you belive the upper limits of HLAs are, concerning lift and RPM?

[mike323]

Oh, I see. So a solid lifter cam will have slightly more duration at a uselessly low lift, which lowers your dynamic compression ratio?

Mike, what do you belive the upper limits of HLAs are, concerning lift and RPM?

The HLA limits are between 7300-7600rpms.
The lift of the valve has nothing to do with the HLA, it's the valve spring that determine the max lift. Max lift needs to take into consideration spring binding.

[Gen1GT]

Looks like I'm going to have to use shim under bucket, because I plan on running til at least 8000RPM. Also plan on getting Eibach valve springs.

[Protoss]

Otto cycle is jargon for '4 stroke'.

no the otto cycle is the thermodynamic cycle for simulating and calculating internal combustion engines. is it similiar to the brayon cycle.

[Gen1GT]

no the otto cycle is the thermodynamic cycle for simulating and calculating internal combustion engines. is it similiar to the brayon cycle.

Dude, what are you talking about? Internal engines ARE thermodynamic, that's the point. The 4 cycle engine was developed by Nicalaus Otto, which is why it's called the Otto cycle.

And it's BRAYTON cycle not Brayon cycle. Brayton cycle is for turbine engines.

You might have heard of the Miller Cycle, which Mazda used in the Millenia. It's the same as an Otto cycle, but uses a supercharger, and the intake valve stays open for part of the compression stroke, which increases effeciency because it puts pressure on the supercharger instead of the cylinder walls.

Diesel cycle engines were developed by....you guessed it, Rudolf Diesel.

[mike323]

Looks like I'm going to have to use shim under bucket, because I plan on running til at least 8000RPM. Also plan on getting Eibach valve springs.

If you're planning on running the engine near 8000rpms you'll need to change more than valve springs. The shim under bucket is a shim used to raise the HLA or even solid lifter since the base circle on the cam was reduced too much.

BTW I would scrap the BP intake manifold and replace it with individual throttle bodies setup in order to get great results above 7000rpms.

The main restrictions on the BP is the intake cam and intake manifold.

[Gen1GT]

If you're planning on running the engine near 8000rpms you'll need to change more than valve springs. The shim under bucket is a shim used to raise the HLA or even solid lifter since the base circle on the cam was reduced too much.

BTW I would scrap the BP intake manifold and replace it with individual throttle bodies setup in order to get great results above 7000rpms.

The main restrictions on the BP is the intake cam and intake manifold.

Are you sure about that? VICS is a pretty good manifold. Plus, plenty of Miata guys run 8-9000RPM.

[jitb37]

im learning alot....keep it up

[jitb37]

99+ is when the VCIS started right??

[Gen1GT]

dude, at 8000rpm, the stock VICS intake manifold is a flow RESTRICTION... the runners are too damn long at that rev range and thus you LOSE power... ITBs are needed for high RPM flow because of the super short distance needed for air to flow into the combustion chamber, they also increase throttle response tremendously... what you take away though is low end torque... it's always a compromise when tuning an engine... you want high RPM performance, you screw the low RPM crap

there's a BIG reason why the MazdaSpeed C-Spec BP-ZE had ITBs and a big plenum you know

I've never had the manifold flow-benched, so I don't know how much of a restriction it is. If I can still get usable power upwards of 8000RPM, I'll be happy. I'd rather maintain the midrange the VICS is good for, since average hp is more important than peak hp. You're partially wrong with ITBs, since they're good for torque too. Since they're small in diameter(45mm being normal), they maintain velocity, but because there's 4 of them and combined volume is large, it's able to flow a lot of air at higher RPM too. I'd love to have them, but you need a stand alone which operates strickly on maps and throttle position, not to mention they cost minimum $2Gs.