Ti Valve Spring Retainers

[Lynn]

Guys-n-Gals,

Well, as the cam is selected and the AFR 205 heads have been checked as to their install height capability, we have narrowed down the springs that will be used to 4 sets. The cam specs Comp 977-16 with 939-16 as the premium choice. The engine builder I have been working with lately, who is very well known in the circle track ranks, says he likes and uses Comp 929-16 springs in a lot of his engines. These will work fine and have just a bit more resistance. There is also a coated version of this spring that uses a molydisulfide coating. This is supposed to give them a incredibly low coefficient of friction on the outer surface of the spring to reduce heat; I guess this works at the molecular level. The coating is also supposed to act as a heat dispersant to draw engine heat away from the springs. I am not sure what the price difference is between the 929 and the 9290, but does this coating sound like something we would need in a 7-7.2K rpm GT40?

Now about the titanium retainers; with all things considered what is your opinion on the need for titanium retainers in the aforementioned engine? At list price, one Ti set is 2.6 times the steel and the other is 2.9 times the price of regular steel retainers. The actual prices are $66.56 for steel, $173.76 Ti-1 and $195.04 Ti-2. Now, I can get the Ti-1 set for $125 on eBay, but that is still nearly twice the price of steel. The one argument for Ti, that I am aware of, is that the springs specified are not exceptionally stiff: 150lbs. on the seat (1.850"-1.9") and 420lbs. at 1.250". I am not going to change valves at this point, so anything I can do to decrease the mass that the springs have to deal with will help. The weight is not given for either retainer so I don't know what the exact weight savings is.

So, what do you think:

Should I go with coated springs?
Should I spring for the Ti retainers?

Thanks,
Lynn

[Paul Thompson 'Hooligan']

Hi Lynn

IMHO, go with the Titanium retainers, we use them in Roys engine and whilst we have changed/used several sets of springs, we still have and use the Ti retainers - money well spent.

I don't honestly know anything about the coated springs you mention, the description sounds a little bit like 'sales-techno-babble' to me. (again - IMHO) [img]/ubbthreads/images/graemlins/grin.gif[/img]

[Lynn]

Paul,

Who made the Ti retainers you used? I was just reading about some Ti retainers galling and cracking somewhat easily. It wouldn't be a good thing to have one break and drop a valve!

The only brand name that was mentioned was Isky. But they were also talking about a Honda team that changed them every season. Some guys in the SBC crowd said they had never heard of an issue with the Comp Cams Ti retainers. Comp was the brand I was looking at and they go to great lengths in their catalog to assure the customer that their Ti retainers are made from a better grade of 6AL4V titanium and that "no longer will you be preoccupied with splitting a retainer and tearing up an engine when turning 10,000 rpm."

Thanks,
Lynn

[Paul Thompson 'Hooligan']

Hi Lynn -

I'm fairly sure they were comp cams - if not i'll post again with correct details.

We used to turn up to 8000prm fairly regularly with these installed in the steel A4 engine. (which will probably find its way into the aluminium semi-monocoque MkII currently being built [img]/ubbthreads/images/graemlins/grin.gif[/img])

[killroy]

You should look at Comp's beehive spring for the big block chevy. It has a 1.880" installed height, 155lbs on the seat, and the o.d. at the bottom is 1.445".

They have the smaller retainers, so you save weight even if you use steel, but they do make titanium retainers that will fit 11/32" valves, and the springs themselves are lighter and more resistant to valve train harmonics.

These are on my short list, they are more expensive than a standard dual spring, but it just seems like a really elegant solution.

Here is a PDF:

http://www.compcams.com/Information/...%20Spring2.pdf

[Lynn]

Built2rev,

There are some down sides to them as well. One big one is that, since they are a non-dampner single spring, if they break, there is a real chance of the valve being swallowed. This is the main reason some head makers (AFR for one) won't use them. They also tend to only allow about 0.600" lift or so. And I have heard of guys having to machine their own retainers because there isn't a very wide range of choice.

On the other hand, Chevy is using them in some production engines. And when you hear claims like the following, it does tend to get one a little excited: "I ran a set of Comp's 918 springs about 2 weeks ago during a test of some new SBF heads from AFR. The 918 spring is designed for LS1s and the diameter is a bit small for the spring pockets in the head, but they worked OK after we cobbled together a retainer/lock combo. We tested three sets of springs and the beehive raised the rpm where valve float occurred from 6400 to 6900 rpm compared to a dual spring with damper and a single with damper, both of which had more seat and open pressure. Comp's BBC beehive can be made to work on the AFR's and is probably a better choice. That spring has more seat pressure and will go to 7500 easily."

Lynn

Edit: Since I made the comment about AFR above, I though I should share with you what we discovered when we were checking the install height and spring pocket depth on my AFR 205s. First, I did buy these heads slightly used and they guy I bought them from may have changed the springs, but I don't think so. What we found was very poor fitting retainers on the springs. Since there was no spring locating device on the seat, either cups or seats, there was far too much room for the springs to bounce around. Use of this setup for to long of a period would have led to worn out spring pockets at best and spring failure at worst. In the middle would not have been optimum performance for sure. The moral of the story is, "just because they came from the vendor that way, take nothing for granted. Check them yourself!"

[killroy]

That's a good point about valve spring failure, but if one part of a dual spring fails, I think you would have the same problem.

The good news about the Big block spring is that it has more installed height, and while the specs say .600" lift, I think their coil bind figure is probably off.

Look at part #26595 here:

http://www.compcams.com/Technical/Cu...ML/329-338.asp

It is their race version with a taller installed height, similar seat pressure, but a 1.100" coil bind figure.

They are different springs, but I don't think that they are different enough to have that big of a gap in the coil bind figure.

Also, there is no retainer problem with the big block spring, normal big blocks have 3/8" valve stems, and they make valve locks that work with 11/32" valve stems in those retainers.

Lastly, these springs have more pressure than the LS1 springs, just what the doctor ordered for a solid roller valve train.

[killroy]

Besides the Chevy LS1, I think the Ford 4.6 and 5.4 liter SOHC and DOHC engines use a beehive style spring also, but smaller with less pressure.

[Dave Bilyk]

Lynn, I would do a cost / benefit analysis here. The cost you already know; the benefit, well you do need to know the masses involved.
The effective mass the valve spring has to deal with is the sum of;
Half the valve spring mass plus
the valve mass plus
the mass of the retainers and collets.

First, calculate this for the standard components.
Then establish what options you have.
Next calculate for each option the reduction in weight, and express it as a percentage of the total as calculated for the standard components.

The percentage figures will be a clear indication of the overall benefit of lighter retainers.

Clearly if you had the masses, you would be able to see the benefit of changing valves, springs and retainers, and where the best weight savings are.
My guess is that the percentage reductions best to worst would come from Ti valves, then springs, then retainers, but it will only be by comparing percentage reductions and cost that you will have clear information to work with.

Normally, to feel that any change was really worthwile I would need about 5%, if the saving was less than 2% I certainly would not bother. On the other hand if we are talking racing and winning, 1% can make the difference, but you can only see whats practical if you consider the cost as well.
Hope this helps
regards
Dave

[killroy]

The real benefit is that his intake manifold makes it a royal pain in the behind to take off the valve covers.

He wants a solid roller setup because more RPM=more power with his combination. Everything he can do to make the valve train lighter and more resistant to harmonics is going to help.

The beehive with titanium retainers is the lightest by a large margin. It's about the same weight savings as running titanium valves with steel retainers and standard springs, but it's only about $250 more than all steel.

It also isn't some monster 200+ lb on the seat roller cam spring, so it won't be as hard on the cam, lifters and rocker arms. This will let him stretch his maintenence intervals while still having a high rpm valve train.

Lastly, spintron results have shown that reducing weight in the valve train does not always increase the stability of the valve train. For example, titanium pushrods will not be as stable as 4130 steel, and will create valve bounce at a much lower RPM.

[Lynn]

Guys,

You are all right, of course. The cam I have specifies the spring rate, 150 on the seat and 420 open. Which aren't monster numbers. If there are indeed beehive springs in that range, I will certainly consider them for the reasons stated. There are, however, tried and true double spring setups that fall perfectly in that range or slightly higher (a little stronger won't hurt you, but a little weaker will for a lot of reasons), so it will probably come down to a cost factor. I have the utmost confidence in the guy I am working with on this who has a VERY good reputation in the circle track world and the experience to almost instinctively tell me if a certain combination of components makes sense or is worth the cost difference in my application. He is extremely busy right now, so I thought I would poll the GT40 community to get their feelings on whether Ti retainers are worth the additional cost. This is especially true when I have read of the galling and splitting issues that have been seen with some Ti retainers. It appears that the problems have arrisen mostly with Russian and Chinese produced retainers where the quality of the titanium that has been used is questionable. It appears that, if one purchases US made products from well known vendors, this issue can all but be eliminated. One of the major factors that seemed to contribute to the retainer problems was the presence of a dampner in the spring set. A careful deburring of the dampner appears to go along way in alleviating the issue. So a qaulity retainer and good spring prep puts Ti retainers on a fairly level playing field with steel where longevity is concerned, but one would have to give the edge to steel just because of the slight uncertainty with titanium. So the real question comes down to my particular cam profile and rpm range that the engine will be run in the majority of the time. For me, this is too close to call and I will let Charlie (the engine guy) make the call; because, either way, I think I'll be OK. If I were building an all out racing motor, there would be no doubt: I'd use not only Ti retainers, but Ti valves as well.

Lynn

[Ian K]

Actually, I'm kind of intereted in this subject too.

DSS Racing now has an option to use their own
high rev mods to their head selection to allow the
use of hydraulic lifters up to 8200RPM.

To quote them:

************************************************************
*D.S.S. "HI-REV" CYLINDER HEAD UPGRADE

The D.S.S. "HI-REV" CYLINDER HEAD UPGRADE allows you to take
advantage of today's " HIGH REV " Hydraulic roller camshaft
technology. We have cam grinds that make power all the way
up to 8200 RPM!

INCLUDES: Special "High Rev" HYD Roller springs, lightweight
Titanium retainers,+.050 extra installed height 10 DEG locks
and check / correct comp heights
************************************************************

If I build a 331, I might look into this. [img]/ubbthreads/images/graemlins/cool.gif[/img]

Check http://www.dssracing.com and look at their
cylinder head section.

Ian

[Lynn]

Ian,

Wow, that is quite a claim: 8200 rpm with hydaulic lifters! They would obviously have to be using very light valve train parts to obtain these kind of revs without collapsing the lifters. I have to believe that there are some restrictions on the lift both ramp and max.

Good luck and, if you go this way, let us know how you make out!!

Lynn

[Lynn]

Well, the conventional wisdom seems to be, if you are not turning your engine over 8K rpm and/or the available springs for your setup are fully capable of handling the mass of the retainers, locks and valves then Ti retainers are probably not worth the extra money. I can obtain springs which are very capable of handling the mass, so it looks like it will steel for me since I don't plan on turning over 7200 rpm.

Thanks,
Lynn