mcipseric

Hi,

Has anyone here replaced their valve springs with the titanium RSR Valve Springs? What are the part numbers and is it a difficult job?

Thank you!

flatsixforme

Geesh, Eric, is today the "I just ran at CFOS and I want my car to be as fast as all those sweet club racing 993s" day? I've seen a couple "RS" related posts out of you!

I can't offer too much info on the RSR valve springs but having just had my valvetrain apart I can tell you that it likely could be done with the engine in the car but access would be tight and you REALLY risk getting a lot of dirt and particles in the engine so I would caution you there. I imagine these are stiffer and obviously lighter. The question I have is whether the RSR used solid lifters or hydraulic and whether that matters in this situation (i.e. can the hydraulic lifter work with an RSR spring). Also, I'd want to know the difference in the RSR cam to see if that would have any adverse effect on only changing the springs. I'm thinking if you are doing the springs to RSR there are a few other motor upgrades that should be done along with them...just my $.02. Hope that helps.

VNTGSPD

Eric -

Why?

There may be a potential issue with the hydraulic lifters and I'm sure others here will chime in to confirm.

But, why??

Unless you are changing cams and modifying the rest of the internals for high rpm duty, I don't see where this "upgrade" will do you any good. Nothing worse then spending a ton of money on mods and then not being able to tell the difference.

mcipseric

I am happy with the car's performance. My best lap was a 1:58 with 150 top speed, 145 mph turn 1 entry and 140 turn 2 exit. I believe I could get down to 1:55 ish on the Roval if I get a better line in turn 1 &2 and get the nerve up to not to lift in the turn 1 entry.....

The purpose of the Springs is to just have a bit more protection from a possible over rev..... not performance.

http://www.youtube.com/watch?v=pVzmg7lqjo4

mcipseric

Hey David,

Agreed, just want more protection from possible over rev. I might be barking up the wrong tree....

FisterD

Eric, Nice video

mcipseric

The Stage IIIs are sounding NICE!!

Quadcammer

I don't think these springs would offer much protection there. They lighten the valvetrain and may be better than a set of worn stockers on that front, but I'd say a new set of stockers would be just as good. Plus the ti springs will need more regular replacement.

Macca

Hi mcipseric. Ive just been through a similar dilemma during my 993SS cam install and back date to solid lifters/rockers. You can see more detail on my thread "self gratrification with pictures...". I didalot of research and talking with various folks.

My 2 cents is that the issue you are concerned about is valve float and/or "pumping down" of the hydrallic lifters. I dont know your engine spec but my advice is unless you are increasing your max rpm above say 6800 rpm using a more agressive cam and a custom chip then your only real concern in these regards is the condition of your current springs and hydrallic lifters. If your engine is factory then I would suggest simply replacing the lifters and keeping regular oil changes. The next stage would be to drop the engine and remove the cam towers to replace the springs, re shim them and while your in there chang the valve stem seals. If you were doing this you would be well advised to consider a more agressive can and backdate to solid lifters/rockers/timing sprocket. You will get 18-20bhp more power if you choose the right cam and this is set up properly. If you are going to this expense for a track engine it would be adviseable to look at the Aasco springs/retainer and seat option. the set is around 700+ usd. Assuming you are having your shop do this job, with springs, gaskets and other while you are in there jobs the full job with cams, rockers, lifters, valve spring kit, gaskets, labour and retiming etc is likely to run you 4000usd.

The next stage is removing the heads. This means you can inspect the valves and valve guides. You could update to tilton gaskets too. More labour all up. Replace any damaged exhaust valves. Probably would be a good idea to get a matchedvalve set and seat grind and clean up from Steve W. New head studs are good too. I would add another 2000 usd at least on top of above for this including labour.

The last step would be bottom end work. Oil tubes, oil pump. you could loose yourself here for 4000 usd incl labour to make a really strong race engine...

Basically what I learnt on my journey is that for a street engine stick to 6800 rpm. The factory springs have been used for years in many 993 applications. They are fine for street and should last a long time. Valve stem seals go hard with age and valve guides do wear over time. Hydrallic lifters can apparently fair over time too.

For a track engine assuming no race class restrictions then if your engine is likely a bit tired you could opt for hot cams, raise the rpm a tad (maybe 6900) using a custom chip and either have the existing springs checked, re shimmed and news valve stem seals or buy a new set. Then revert to solid lifters. This way you rid yourself of the valve float AND pumping down issue. Your bottom end is still your weakest link.

I dont know a nut from a bolt but this is what I learned on this forum and from talking with my engine builder, Steve w and Colin B etc. Steve is a big fan of keeping the hydrallic set up in a non "race" engine and going for an RS cam...

Hope ths helps...

M

Bill Verburg

I don't believe that even the RSRs used Ti springs, retainers, yes

the limiting factor on revs is not the hyd lifters(these are after all used on 8K rpm GT3s), it is the con rods, bearings, bolts and oiling

yes, the seals in the hyd lifters can fail and will then need to be replaced

John D wrote a great pice on replacing the hyd lifters, here

chaoscreature

There was a guy at the last PCA Tour with an SL63 that also races a 993 Targa. He has done some internal engine mods for durability... I think he has titanium springs and custom valves etc.
I would try to get his contact information and ask him. I feel horrible because I forgot his name (I think it might have been Javier?), but all the local 993 people seem to know him...

cgfen

titanium SPRINGS?
i guess it's possible, but i'm trying to imagine drawing Ti into a wire and making springs.
Ti valves = yes
Ti retainers = yes
Ti springs = i've not seen them, but i'm not really a gear head anymore.

have fun.

Craig

Steve Weiner-Rennsport Systems

Precisely!!

Titanium is a VERY poor choice for valve springs and thats why they are VERY rarely used. There are good alloy steels used for these applications, however the real trick is to avoid using springs with too much seat pressure, otherwise one suffers excessive valve train wear. The final choice depends on what RPM operating range the engine is used in.

Over time, OEM valve springs do lose their seat pressure due to fatigue and that lowers the threshold of valve float (if you miss a shift). This the main reason we use good aftermarket springs in street and track cars.

Now then, Titanium is an excellent choice for valve spring retainers in these engines when used for the track due to the propensity to crack of the OEM (they are sintered metal) ones if the valves float. Ti ones are more durable and they lighten the valve train weight.

As Bill said, Porsche hydraulic valve lifters work pretty well and the only reason to change them to mechanical ones IMHO, is when the engine will see operation above 7K RPM. Over time, the seals do fail and they lose their capacity to hold oil so we replace them when they get noisy (its an easy job).

Lastly, even with RS cams, these engines are well past their BHP & torque peaks above 6800 RPM so there isn't a need to twist it any harder, especially with stock rods and bearings. There are certainly many things one can do to the bottom end to ensure improved durability, however thats a totally different discussion,.....

Hope this helps,

mcipseric

WOW! I love this place. I think I will leave well enough alone and work on the nut on top of my shoulders.... :-)
Thank you, everyone!

geolab

Does anybody have figures on factory valve springs seat pressure and open pressure ?