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Sun Aug 05, 2012 11:14 am

I was told by a VW parts supplier that installing 1.25 rocker arms on my stock heads and using the stock cam would make my cam shaft prefrom as if it was a aftermarket 110 cam.He tired to explain over the phone how this would work but I didnt understand how it would do so.
Could someone please explain it to me so I can read it for a better understanding?Thank you

Sun Aug 05, 2012 11:52 am

the stock cam has .334 valve lift (in the intakes) .334x 1.25 = 4.18

engle 100 has .392 if your just using the stock 1.1 rocker with it .392 x1.1 = 4.3

so the valve lift with be almost equal. (but actually the engine 100 is .420 lift so more the equal of the stock cam with 1.25 rocker)

however and here is the big how ever, the stock cam has 214° duration (time valve is open) This will be slightly lengthened by the 1.25 rockers So lets call it 220°

the engle 110 has 247° so there is your significant difference

So a stock cam with 1.25 rockers does not = a engine 110 with 1.1's it does not even = a engle 100.

if people cold just get a engine to think it had a engine 110 by putting 1.25's on there stocker no one would be buying 110's

Sun Aug 05, 2012 12:49 pm

dubhead74 wrote: I was told by a VW parts supplier that installing 1.25 rocker arms on my stock heads and using the stock cam would make my cam shaft prefrom as if it was a aftermarket 110 cam.

Your parts supplier is clearly overstating the truth to sell you parts. Adding 1.25 ratio rockers to a stock engine will only add about 2-3 HP at best. You might be able to feel a very tiny bit of difference on the old butt dyno.

Sun Aug 05, 2012 1:05 pm

Thank you..... Krusher that helps and makes a ton of sense

Sun Aug 05, 2012 1:19 pm

right on vw racer dave . you allso for got to tell him that a stock cam is not ground to use high lift rockers of any kind . i know i am going to catch hell for saying that lol but its true and yes guys will tell you it works great use a cam thats made to use high lift rockers . allso there are some real cheap junk 1.25 rockers being sold. if you must use 1.25 buy good ones . to me you wont feal any more power . buying the 1.25 rockers . just my two cents spencerfvee vwracerdave wrote: dubhead74 wrote: I was told by a VW parts supplier that installing 1.25 rocker arms on my stock heads and using the stock cam would make my cam shaft prefrom as if it was a aftermarket 110 cam.

Your parts supplier is clearly overstating the truth to sell you parts. Adding 1.25 ratio rockers to a stock engine will only add about 2-3 HP at best. You might be able to feel a very tiny bit of difference on the old butt dyno.

Mon Aug 06, 2012 12:51 am

Would you like to name the "parts supplier" that tried to sell you this idea?

Mon Aug 06, 2012 11:53 am

spencerfvee wrote: . you allso for got to tell him that a stock cam is not ground to use high lift rockers of any kind .
While the stock cam may not be designed to use higher ratio rockers, they do work. Back in the day, guys used to use 1.4:1 rocker on stock cams with good success.

If anyone wants to use 1.25 rockers, go ahead, they will work. Sure, they won't make as much hp as installing a W-100 cam, but they are a hell of a lot easier to install.

Mon Aug 06, 2012 12:25 pm

krusher wrote: Would you like to name the "parts supplier" that tried to sell you this idea?

CIP1 feed me a line of BS to sell 1.25 rockers.
FWIW you'll likely need shorty pushrods too.

Tue Aug 07, 2012 12:45 am

JasonBaker wrote: FWIW you'll likely need shorty pushrods too.
The difference in geometry between 1.1 and 1.25 rockers is very little. With the same pushrods, you can juggle things around with rocker stand shims to get things working right.

Tue Aug 07, 2012 6:01 am

Bruce wrote: JasonBaker wrote: FWIW you'll likely need shorty pushrods too.
The difference in geometry between 1.1 and 1.25 rockers is very little. With the same pushrods, you can juggle things around with rocker stand shims to get things working right.

Yes, on some types of rockers you can do that. However, The ones I bought get adjustments made on the pushrod side and use's an allen bit instead of a flathead srcew driver.

My OG's were worn slap out. I like the way adjustments are made on the new ones. But in saying that, they may not be for everyone. Vwracerdave had made it clear in other threads in the past that it's problably not worth the money for a few hp. I would tend to agree. But like I said mine were worn slap out

Not saying you must have shorter pushrods, but you might need too.

Tue Aug 07, 2012 9:06 am

I dont think the stock cam cares what rocker you use on it, the rocker changes nothing the cam is doing, just after the end of the pushrod to the valve.and the oe cams are deburred&champherd correctly whtch I havent seen on any aftermarket cams, thus I do it my self so the cam dont eat it lifter lunch.

Wed Aug 08, 2012 6:21 am

When the cam/rocker combo is already providing all the lift the heads need, Dave is right (and this is what he is referring to). A good example is stock heads with an Engle W100 or W110; either cam with 1.1 rockers will give about .420-.430" valve lift, and since stock heads don't really flow any more past .400" there is very little to be gained by adding 1.25's and increasing the lift another .060". Take those heads and port them, and now you have a different scenario; the intake ports will increase in flow and level off at about 1/2" valve lift and that extra .060" is needed to make the heads perform to their potential. NOT using 1.25's is leaving power on the table. Going from 1.1's to 1.25's also increases the duration as measured at .050" valve lift; 4-5 degrees in some cases (Engle W125, noted by John Maher in this thread- http://cal-look.no/lounge/index.php/topic,13225.0.html look for the graph 2/3 down the page).

As Krusher's numbers tell, this is why adding 1.4's to a stock cammed motor (with added carburetion and exhaust) works- the added lift now uses all the flow the heads can give. Adding 1.25's instead will also make a difference, though not enough to really be noticeable, and since the rockers will cost the same (or close) the higher ratio is the best choice here. The dur @ 0.050" will increase (7? 8? 10? degrees), but since VW was so conservative with their cam timing (214' @ 0.050") this is nothing to worry about.

As usual, just my 2 1/2 cents (I'm Canadian, eh). Al

Wed Aug 08, 2012 11:41 am

correct in the added lift wont help much if the heads are already at thier max, but having the valve open longer will and thats what your doing.porting will help, but biger valves unshrouded and ported corectly will help morebetter, and a bit more cr helps too in most all cases.this is a never ending thing till you sell it& get a toyodie so you can race garfield and get to the speggettiiee first for a change.