So how light are TI Valve retainers?

[jluetjen]

Anybody ever weigh them?

[racing97]

12g vs. 19-20g for stock


Best Regards

[jluetjen]

BTW Racing97, the stock retainers that I weighed (from a 2.4 engine) weighted 17.35 grams.

Thanks for your response.

[David]

I don't know the weight, but I just got off the phone with EBS talking to them about the work they're going to do on my 930 heads. Don said with their valve springs and titanium retainers, the engine would be good for over 8000 rpm! I will still set my rev limiter at about 7500 and try not to go over 7000.

[racing97]

Every thing has its degree of importance. Years ago (late 60's) GM did some work with a Strobe Tach for thier Can Am motors. and founded the basis for the Spring design based on Harmonic Number and Natural Frequency (in regards to racing) Although Spring material has improved tremendously over the years the concept sitll is weight of Sprung Mass, thusly Tia Valves,Retainers. The only question is does the Cam you are using warrant the expense and does the Motor really make its power in the higher ranges of RPM. The only real use I have seen in Porsche Engines is as a replacement for the forged stock units over cracking issues.

Best Regards

[jluetjen]

David;
I've been trying to break down the contribution of stiffer springs versus the TI retainers. Reducing the valve train mass is a free win since it doesn't increase friction. On the other hand "competition" valve springs carry a significant increase in friction as a result of their increased pressure. So what's the trade-off???

Based on what Don said, their springs and retainers are a panecia for rev's. But on the other hand Grady has first hand experience using stock with Ti retainers and an 8500 RPM rev limit. What are the factors that were different in Grady's example compared to what Don was thinking about? (To answer my own retorecal question, such things as cam choice and valve weight matter as well).

That's the problem with a lot of the information that people toss around, it's so vague and self serving as to be almost useless for making a decision. According to my estimates, using TI retainers (a less then 4%-5% reduction in valve train weight) may only result in a 100 or 200 RPM (2-3%) increase in the peak engine speed.

[garibaldi]

Yeah, but they dont last very long. If you run them, pull them out after a while and take a look at where the spring rides and where the keepers sit. For race motors that need the extra edge, but come apart often they are fine. But for a street car, that you want to put together and not take apart for another 100,000 miles, I woudl use the steel retainers.

[jpnovak]

Does this mean that the high-rpm ability is due to the reduced mass of the keepers/retainers or the increased spring tension preventing valve float?

Can you still safely spin to 8K with stiffer springs and steel retainers? John's numbers make sense.

[cstreit]

Christian,

How many hours are we talking about here?

I realize the wear would differ based on spring pressures, but can you ballpark it? 20 hours? 60 hours? 300 hours?

[David]

I had decided weeks (OK months) ago when I started this project that I would use steel retainers for longevity so I think I'll stay with steel retainers. Does anyone have a feel for what the disadvantages of heavier springs are? HP loss, engine acceleration, cost, etc.

[racing97]

As Jamie stated high Rpm operation is improved both for both reduced mass and increased spring tension. In defense of improved components
the Spring is probably the important factor and remember that the Cam Harmonics is were we began. But once again make sure you don't want Rpm for Rpm sake and your components can sustain the load.
Everything is important in regards to Racing Engines it just has to be applicable to your situation. the stock Porsche spring if I remember correctly has a Spring Rate of 315lbs per in at 34 mm of installed height it exerts 74 lbs and will tolorate 11.8 mm of lift to an open pressure to 227 lbs at 1.25 mm from coil bind. it has no interference between inner and outer coils but the windings will reach coil bind on the inner way before the outer, it is the proximity of the coils that aids the damping, that is one of our poor Harmonic issues with the stock component
The other reasons for improved Springs are increased lift and duration capabilites for competition use, and flat out missing a shift and being able to absorb that energy in your valve train. To increase the capabilities the Wire Stress must rise to compensate, ergo the increase in pressure in lbs per inch. The Spring design must be reasonable and many manufacturers make a one design that fits all, which is not prudent.

Best regards



Best regards

[jluetjen]

While were at it, does anyone have information on the different spring pressures. The stock spring data was listed by racing97 (and elsewhere on this BBS), does anyone have data on the Aasco springs or other products. Do they all have the same pressures?

This is of interest to me since I'm building a full-race motor that will most likely be rev-limited by the mandated 34mm venturis in the carbs. So while it looks like I need more pressure to deal with the cams' acceleration, I'd rather not run any more pressure then I need in the interest of reduced wear and friction.

[racing97]

I believe the Aasco spring is somewhere around 360lbs per inch 75 to 80 lbs @ 34 mm, and will allow a lift of 13mm or so @ 1.25 from coil bind
with 270 lbs open pressure at 13mm. It also has a slight interference between the inner and outer springs of about .03 to .04mm. I think the wire dia is just a tad larger on either the inner or the outer but I don't think both are larger. I think you massage the perch just a bit for fit.
It is a good design for porsche not to overboard in spring rate and definately capable of high RPM and Harmonic dampning.
I sorry I don't have any more spring data the project I was doing only had Aasco and stock.

Best regards

[911pcars]

Racing97,
I've been looking for those spring specs for awhile. Thanks for sharing.

Sherwood

[camgrinder]

Elgin Ti retainers weigh 13.2 grams. The retainer is made for a larger diameter valve spring than the normal aftermarket spring.
Using Titanium allows a better cross-section in the critical areas without a weight gain.
If there is signs of wear under the retainer where the spring rides, this usually means the valves have been floating. The retainer should have a snug fit into the valve spring, this helps dampen vibration. A slight interferance fit in between the inner and outer can also dampen vibration , but sometimes causes friction.

[KobaltBlau]

Originally posted by camgrinder
Using Titanium allows a better cross-section in the critical areas without a weight gain.

Do you guys recommend putting these in a 100k mile street/DE engine if the desired rev limit is high?

[camgrinder]

Thats a tough question. I recommend the retainers and valve springs for camshafts that require them. I doubt an 8000 RPM 2.7 litre is going to last 100k.
I would recommend them on a street 930 that shifts at 7000 RPMs with a set of Evo camshafts. We have been selling Ti retainers for 911 Porsches for at least 14 years, and I have never even heard about a retainer breaking. We used to make chrome moly retainers for our old design valve springs but the demand was so low we discontinued them.

[Grady Clay]

I made the decision that I wanted light weight valve train as opposed to stronger springs. The benefits are obvious; less load on the cam, rockers, and many other parts.
There is a cost ($) to this. I used Factory Ti retainers and 935 (non adjustable) forged rocker arms. These are expensive Porsche race parts but the best for racing. I was able to use stock springs, set at the high end of stock setting. I don’t think we ever saw piston to valve contact, even when I worried about an occasional 9000. The clearances were always close enough for the valve to leave a shadow on the piston.

The first time I ran one of these engines, we did a maintenance overhaul at about four hours. No problem and I reduced the deck clearance. The next time was perhaps 6 hours. Again, no problem and I reduced the deck some more.

Keep in mind I had an engine dyno to run-in the engine, re-torque the heads, reset the valves (PITA), and check cam timing and everything else.

I settled in on 12 hours (2-4 race days) just to be careful. I would much rather spend a little too much rebuilding and a little too often than suffer the consequence of a catastrophic failure. There are a LOT of expensive parts. Catastrophe can happen anyway, regardless of your care, fortunately not to me.

A maintenance rebuild consists of gaskets & seals, flywheel bolts, main & rod bearings, rod bolts & nuts, piston rings, and very careful touching up the valves. Very careful cleaning and inspection of everything is crucial.

A 911S engine that is never “buzzed” (seen over 7200) is a VERY long lived engine. I wouldn’t hesitate to run a well built 911 to 7200 over a 100K+ lifetime.

These racing parts are not suitable for use on the street. They are very expensive and a PITA to service. You can’t adjust the valves in the car. I used both center oil cams and the spray bar to keep the cams and rockers sufficiently lubed.

Best,
Grady

[jluetjen]

Thanks everyone for sharing. This turned out to be a very informative thread.

[Henry Schmidt]

A quick comparison.
Valve springs are important, but racing springs are only needed for sustained high RPM.
Remember 962s ran specially sorted stock springs.
Options
Stock spring :specs are well known , with a any real lift these will coil bind or have less than 50 lb @ installed hieght.
Aasco spring : 80 lb installed 260 lb over the top (.070 from coil bind) max valve lift +or- .490
Supertec spring: 80 lb installed 265 over the top (.070 from coil bind) max lift .525
Most other after market springs 100 lb+ installed way over 300 over the top. Who whats that wear or friction? Just so you know, most after market Porsche "racing" springs are Chevy or Buick or who knows what.
I think only Aasco and Supertec are specialy designed and manufactured.
Retainers:
Factory steel : 19.4 grams
Titanium: 11 grams
Valves:
Stock :49 mm intake 111 grams
Del West Titanium : 49 mm intake 78 grams

Conclusion: Money talks
If your engine spins 7500 or less: stock everything properly shimmed for 2.0 to 2.7 Ty retainers for 3.0 and larger.
If you'll see 8000 : ty retainers and good springs.
If you're made of money or you just like the best:
Ty valves, Supertec springs and Ty retainers.
Don't forget, with all that Ty why not add some lift?

Stock, Aasco, Supertec



Stock, Titanium



Stock steel, Del West titanium (available in stock @ Supertec)

note the Ty valve is not concave, more compression?