Engle W-120 with 1,4:1 ?

[RSK-718]

Hi Folks
Have a friend with a dilemma, he has a freshly build 1835cc with a Engle W-120, nicly hand ported heads with 40x32 and new dual springs.
Now what to use, he has one set of 1,4:1 rockers (measures 1,37:1) and one set of 1,1:1, the springs can handle the lift with the 1,4 without coilbind.
He knows the cam is not designed for 1,4 but would really like to take advantage of the nicly ported heads.
Use the 1,4 or 1,1?
What could happend?

[dyno don]

Use 1:25's for xlnt results...  Tested and proven/...and yes, you can use and run the 1:4's but the cam is NOT designed for them and you will experience early valve train wear and internal wear as well. Now get back to it and enjoy it...!!  Good Luck

[dirk zeyen]

Use 1.25!!! 1.4 is to much lift for a 40 mm valve and like said before it kills your valvetrain!!!

Greetz: Dirk (2017cc 40/35.5 Valves W120 with 1.25 Rockers and 45DRLA)

[RSK-718]

Doing some calculations, w120 has 10,08mm camlift.
With 1,25:1 valvelift is 12,6mm.
With 1,37:1 valvelift is 13,8mm.
Is really the 1,2mm extra lift gonna kill the valvetrain?

[richie]

Doing some calculations, w120 has 10,08mm camlift.
With 1,25:1 valvelift is 12,6mm.
With 1,37:1 valvelift is 13,8mm.
Is really the 1,2mm extra lift gonna kill the valvetrain?

The speed the cam opens the valves with those rockers is what will do the damage,the 120 has about the same lift[0.1mm less] as a fK87 at the cam,that is a big cam with 1.4 rockers on it

It would be better to swap the cam out for one designed for 1.4/1 rockers

cheers Richie

[RSK-718]

OK, so consensus is that the valve train will suffer damage.
Are we talking wear or breakage?
What part(s)
Valve?
Seat?
Guide?

[Zach Gomulka]

OK, so consensus is that the valve train will suffer damage.
Are we talking wear or breakage?
What part(s)
Valve?
Seat?
Guide?

Put it together and find out

[bugnut68]

OK, so consensus is that the valve train will suffer damage.
Are we talking wear or breakage?
What part(s)
Valve?
Seat?
Guide?

Contact Engle and ask them specifically what factors come into play where cam design and their respective rockers come into play.  What better resource than the manufacturer?

The general consensus here is to use the cam with rockers its designed for, or else pursue a cam designed to be used with 1.4 rockers.  The Engle W series cams are designed for 1.1 or 1.25 rockers. 

[dyno don]

DUDE...  Run the 1:4's....  its NOT MY engine..!!  Although the measurements dont appear that CRITICAL to YOU, I can assure you, that with over 40 years experience in the VW industry, having( been there and done that)... you will encounter premature valve train as well as internal problems from lifter bore failure, plain and simple..!! The 1835 in question will run just fine with the 1:1 rockers. The 40x35 heads no matter who ported them will only carry so much air to the valve. Carbs,compression,and exhaust all play a critical role as well. Yes, you can run the 1:4's as some off roaders have as well as short trackers being that most of the driving is accomplished in a short time frame but dont expect ANY life expectancy from your engine build if wanting to drive,enjoy,and appreciate for any length of time. A cam designed for 1:1 rockers will accomodate 1:25's  quite nicely and would be the most exotic in my humble opinion to use without encountering a premature mechanical failure.  Good Luck, Dyno Don   www.dynodon.net

[Bruce]

. The 40x35 heads no matter who ported them will only carry so much air to the valve.

This and what Dirk said is why using 1.4 rockers is a complete waste if effort.  You can hang the valve open further and it will NOT flow more air.  Now if you had a 44 mm valve, the increased lift will likely flow more.
When I ran a W-125 cam with 40mm valves, I tried using 1.25s instead of the 1.1s.  The engine didn't make any more power, so I went back to the 1.1 rockers.  And the engine lived a long and happy life.

[Jim Ratto]

Doing some calculations, w120 has 10,08mm camlift.
With 1,25:1 valvelift is 12,6mm.
With 1,37:1 valvelift is 13,8mm.
Is really the 1,2mm extra lift gonna kill the valvetrain?

It's how fast the spring/keepers will be accelerating/deaccelerating. It would be hard to find a VW sized dual spring that could track the profile seen at the "leveraged" side of the rocker. I once made a plot graph in MS Excel of a few VW cams in lift/degree @ lobe, then "just for fun" added a ratio multiplier to the graph. The lift per degree rate with 1.25 even on cam designed for 1.1:1 is pretty eye-opening. What you think is .050" lift happening @ x degrees (lobe) is now happening much earlier, and by looking @ how "steep" the ratio-rockered valve lift (not lobe lift) is compared to lobe lift you can see rate of lift is crazy. I did a stock cam with 1.4 mutiplier and it was easy to see why that "works". As far as what's going to die.... springs, keepers, keeper grooves on valve will widen, retainers might pull through, pushrods might end up in knots, broken lifters.... in other words, catastrophic. I know someone that ran 1.4 on a W125, and when all of the above happened it was all over.

[fish]

I wouldn't do it, but then again I'm currently setting up FK43 @ 108* with 1.25 rockers on a turbo motor so I can get a long valve train life without chasing every ounce of HP.
I will swap you the 1.25 for your 1.4 rockers.

[Bruce]

... I'm currently setting up FK43 @ 108* with 1.25 rockers on a turbo motor so I can get a long valve train life ....

My engine has an FK-44 with 1.25 rockers.  120k km on it so far.

[fish]

Yep the valve train lasts so much longer when the ramp speed is slowed down @ the rocker.

[Bruce]

And you use soft springs.
When I built my engine, I installed some well used Bugpack VW sized duals.
The only downside is that the engine does not want to rev past 6500.

[fish]

I'm using new duals in DDR heads have not measured pressures yet.
Your heads or carbs may be the culprit in limiting the revs, FK44 should rev past 6500 even with 1.25

[chopper476]

have you considered an engle fk8? would suit the combo well i feel.