Alu push rods vs spring preassure

[Eddie DVK]

Call me stupid, but I won t get it, we all use the same headstuds, aren t they keeping the heads / cilinders from expanding?

Regards confused Edgar

[Airspeed]

Now I am even more confused, my point was a relatively cold engine[alcohol fuel] with good oil temp and I still have enough cylinder expansion[steel cylinders,not cast] to gain 0.030 thou lash from cold,I am hoping ally pushords would gain some of this back by expanding more than the chromoly I used, I think that 0.030 thou lift lost is alot

cheers richie

Yeah, brainfart on my side, sorry: Of course your (steel) cylinders have expanded considerably more then usual in this case, resulting in overly large hot lash.
Maybe your right and steel cylinders expand more then cast iron. I still think your cylinders got very hot, despite the use of a fuel that gives relatively lower EGT's then gas.
Either way, yes, running alu pr's will reduce the lash.
Caution should be had too as you're probably running a drag cam with very early exhaust valve opening and on high boost that can ask (too?) much from the strength of ally pr's.
I have seen pics of some 'other' pushrods from you that weren't pretty 

greets,
Walter

[John Maher]

Call me stupid, but I won t get it, we all use the same headstuds, aren t they keeping the heads / cilinders from expanding?

Regards confused Edgar

Yet another variable to throw in the mix.... head studs expand too.
They help limit overall engine expansion but can't eliminate it completely.

If a head stud had zero expansion, effective head torque on a hot engine could be in excess of 60ftlb.
Remember how often pre 1970 engines used to pull their 10mm head studs?

[ovaldriver56]

Hi

I´m currently working on my valvetrain-setup and have a question to the experts

Parts:

 - SLR XR310 cam
 - 42 x 37,5 valves
 - 1:1,4 rockers
 - 56g T. Pieper Lifters
 - Alu-Pushrods T. Pieper
 - Ti- retainers

I´ve got a set of vw650 springs and am thinking about just using the outer spring. The single spring has 48,5kg at 39,6mm and 115,5kg at 25,66mm (valve lift= 13,94mm).

Do you think that is enough spring pressure for my setup?

Mario

[andy198712]

i too am trying to find a spring.... but trying to find the recommended spring pressure for the 86B is proving tricky,

does it work like that? you start with a reccomended pressure at the cam and then that must be adjusted for weights of valve train parts or what?

i've emailed comp cams about their beehives and they asked me about the spring pressures for said cam ......

seems quite the black art!

[Shag55]

In our industry it's a trial and error situation most of the time.
The xr310 is not to aggressive. We had some float above 7k with the std  Bugpack dauls then went to the 650s and no issues since. Motor is 2110 with 42x37 heads and 10.0:1 comp  street motor.
I'd keep the inners as they act as a dampener which is important.

[spanners]

Gentlemen, no ones mentioned head expansion yet, which surprises me, as its a considerable part of the overall expansion rate across the width of the engine, with the capability to pull studs so easily, VW under estimated the pulling power of head expansion when with engine development the extra  horsepower and heat  increased, and the long type rocker studs anchored in the combustion chamber roof became unreliable and pulled out, these were designed to allow the head to expand and grow over the stud seal in the rocker chamber floor, oil leaks were common in the seal area, then the mk2 version was a failure also, and finally we got the 311 head with the rocker studs fixed to the rocker chamber floor. with the early long stud motor, the valve clearances decreased with warm up, with the 311 head, they increase as you know, one advantage of the modern Multi valve engines lighter valve assemblies, is the ability to run hydro lifters at up to 8000 rpm, now if we could do a similar trick...

[bedjo78]

 130psi seat pressure on 48x39 SS valves. With aluminum pushrods and TP lifter?  Posible to rev 8000rpm? Fk89 with 1.5 rocker

[TexasTom]

There are things about your engine you may consider as not being directly related to the valvetrain but can still play a part in whether you float the valves or not.........

Regarding engine expansion (as mentioned in my previous post when talking about aluminium pushrods), an interesting point came up in conversation with Johannes from JPM the other day.... aluminium cylinders expand approx twice as much as cast iron. Zero cold lash becomes as much as 1mm (.040") when the engine is hot. All camshafts feature relatively gentle opening and closing ramps, designed to smoothly take up slack in the valvetrain (valve lash) before applying rapid acceleration to lift the valve off the seat. Most aftermarket cams feature an opening ramp on the assumption hot lash is approx .006" to .008". But with 1mm (.040") hot lash, the cam is well into its acceleration phase while the valve is still on the seat. WHACK!!

Same thing happens on valve closing.... instead of being decelerated in a controlled manner, the valve smacks into the seat before the lifter has made it on to the closing ramp of the cam. In this situation, regardless of what valve springs you're using, the valvetrain can never work as intended, except for the first few seconds after you set valve lash.

Just another example of how seemingly unrelated components can affect the end result and why it's often impossible to make a specific recommendation without taking a whole lot of stuff into account.

Does any one make cams with really soft initial ramps that would work better with aluminum cylinders? I'm thinking something that goes to 6500...

JPM
 
TxT

[K-Roc]

Hi

I´m currently working on my valvetrain-setup and have a question to the experts

Parts:

 - SLR XR310 cam
 - 42 x 37,5 valves
 - 1:1,4 rockers
 - 56g T. Pieper Lifters
 - Alu-Pushrods T. Pieper
 - Ti- retainers

I´ve got a set of vw650 springs and am thinking about just using the outer spring. The single spring has 48,5kg at 39,6mm and 115,5kg at 25,66mm (valve lift= 13,94mm).

Do you think that is enough spring pressure for my setup?

Mario

Hi you should not run a single outer spring by itself the harmonics will be very bad, the springs are designed by the engineer to work as a pair.
If you desire a lighter spring pressure, find a lighter dual spring set, or a single spring with a damper. ( or ovate wire beehive springs)

Cheers. K-Roc,

[neil68]

I run Logmech aluminium pushrods, Raptor camshaft, JPM 230 heads and k800 I have reved it over 8 000 rpms without any problems. Last run I had 7600 rpm over the finishline with 2.4 bars of pressure. I think the engine is more quiet and responds quicker on the throttle.

I have a similar combo:  Raptor 06908 camshaft, JPM MS230 heads, CB 650 springs,  and have been using Manton chromoly pushrods.  However, I find that when the engine warms up the clatter starts!  I pulled a valve cover and measured valve lash at 0.015" (0.38 mm) after hot lapping at the track.

Just ordered a set of Logmech aluminum dual-tapered pushrods.  Should also help in city driving.

[Udo]

I think you can not run the CB 650 springs with aluminium pushrods - results would be interesting

Udo

[Fiatdude]

I've ran the dual taper AL push rods with the 650 and 800 springs with a 86b and 86c cams respectively -- I ran a zero plus (tightening) a 1/4 turn for my cold adjustment on the 86c with the 800's --

I recently changed over to a single beehive style springs, Chromalloy push rods, and a smaller Pauter pro turbo cam just to get away from a issue I was having with breaking rocker studs and my HP only dropped about 5% from the big stuff and my max RPM is down to 6500. (With zero reliability issues so far)

I was talking to one of the Pro Mod teams and they are running HUGE spring pressure rates (which they wouldn't tell me what they were) to counteract the high boost levels, they are running a cold lash at zero plus one full turn with their 1/2" Aluminum push rods -- They said that most of that full turn is just made up taking all the slop out of lifters, push rods, rockers, and valves... ......

[JS]

Don´t know about the 650´s, but I have run K800´s with aluminium pushrods previously, without problems. Just be sure to get some made from a good alloy, like 7075.

[Udo]

And with what alupushrods did you run the k-800 ?

Udo

[BeetleBug]

I have used JPM alu pushrods for the last 6 years or so. K800`s, BugPack Chevy, Oteva and CB650 springs.

Best rgs
BB

[JS]

And with what alupushrods did you run the k-800 ?

Udo

Udo, from JPM.

[Jim Ratto]

I use Connolly's HD aluminum pushrods in my car since 2001-2. That includes against ERCO triples set up 0.070 from bind and most recently CB650's, @ 365lb over the nose and regular 7500rpm blasts. No issues in 13-14 years.

[neil68]

I use Connolly's HD aluminum pushrods in my car since 2001-2. That includes against ERCO triples set up 0.070 from bind and most recently CB650's, @ 365lb over the nose and regular 7500rpm blasts. No issues in 13-14 years.

I also ran a set of the straight 3/8" ACN HD aluminum pushrods for many years, without issue.  However, when I changed my engine width (then the alu pushrods became too short), I decided to go with Manton chromoly, since I had a lot more HP.  They have been great, but just a bit too noisy from valve train clatter when driving around town.

[JS]

I use Connolly's HD aluminum pushrods in my car since 2001-2. That includes against ERCO triples set up 0.070 from bind and most recently CB650's, @ 365lb over the nose and regular 7500rpm blasts. No issues in 13-14 years.

I also ran a set of the straight 3/8" ACN HD aluminum pushrods for many years, without issue.  However, when I changed my engine width (then the alu pushrods became too short), I decided to go with Manton chromoly, since I had a lot more HP.  They have been great, but just a bit too noisy from valve train clatter when driving around town.

Neil, I have the same experience from my previous pushrods(Manton).

[neil68]

Just received my Logmech dual-tapered aluminum pushrods today.  Shipping from Sweden to Canada was prompt, with excellent email contact throughout!

[Airspeed]

I'am gonna use the dual tapered alu pushrods from Thorsten Pieper, black anodized. They look very high tech and nice.
Its nice we have so much choice these days in quality stuff!

[Udo]

Just received my Logmech dual-tapered aluminum pushrods today.  Shipping from Sweden to Canada was prompt, with excellent email contact throughout!

Looking nice

Udo

[pupjoint]

Just received my Logmech dual-tapered aluminum pushrods today.  Shipping from Sweden to Canada was prompt, with excellent email contact throughout!

bump for this old topic. Neil, u tried on the logmech dual taper aluminium pushrods yet?

thinking of using them on my 2110, Tims Stage 2, Snakeskin valves, titanium retainers, VW650 springs, JPM 01008

[richie]

I have tried a set of JPM ally pushrods on CB VW650 springs and worked very well

cheers Richie

[pupjoint]

I have tried a set of JPM ally pushrods on CB VW650 springs and worked very well

cheers Richie

great. thanks for the feedback

[neil68]

Just received my Logmech dual-tapered aluminum pushrods today.  Shipping from Sweden to Canada was prompt, with excellent email contact throughout!

bump for this old topic. Neil, u tried on the logmech dual taper aluminium pushrods yet?

thinking of using them on my 2110, Tims Stage 2, Snakeskin valves, titanium retainers, VW650 springs, JPM 01008

I never got around to using the Logmech aluminum pushrods yet.  I'm still experimenting with engine width (cylinder shims/head gaskets) and didn't want to cut the pushrods until I finally settle on the new deck height.  I will use them next spring with my CB650 springs.  It's snowing here now, so no racing until April