Itinerant Air-Cooled

I would gladly second the Raby recommendation. He has a cam that will make more power and let the engine run cooler. The 9550 I think.

vic74 wrote:Thanks for link Bleyseng-I like the way that the Raby components are sold in comprehensive kits. Helps to eliminate a bad part choice by a newb like me! His expertise is worth a lot for sure if I go with a non-stock option. People seem to be consistently happy with his stuff.

Thanks for the CB "econo cam" recommendation. What improvements did you notice? Looks similiar to the web 73 I'm also considering. Sounds like your pretty happy with it and it might work with stock solexes which I may use. I'm wondering if either of these cams would help lower CHT's or otherwise benefit a loaded westy.

I don't plan on keeping the progressive permenately, but I hope I can break in the engine with it. I doesn't work great in the winter but does pretty well the rest of the time (at least with the stock cam). I have some stock solexes that need to be re-bushed/rebuilt, and'm I'm assuming re-jetted for a 2.0. I'm also considering dual webers-but I don't want to have to set up dual carbs at the first start up. Thanks for the input so far.

The Raby cams have his special exhaust valve timing duration so that CHT's go down. The Web73 and I'd guess the econo cam have the same as stock exhaust duration but different than stock intake lifte and duration.

Oops double post...

Curious about how these numbers relate to performance.

The following chart is a comparison between the Webcam 107i grind and the (webcam stock grind)

Volkswagen Type 4 8v
Part #: 00-612 (00-370 ; 00-372)
Grind: 107i vs (Stock)
--------------------------------- Intake------------ Exhaust
Valve Lash (Inch):------------ HYD------------------HYD
Valve Lift (Inch): -----------.430(.333)------------.430(.313)
Valve Lift (mm):------------ 10.92(8.46)----------10.92(7.95)
Advertised Duration:--------255°(224°)----------255°(230°)
Duration @ 0.050":--------- 225°(196°)----------225°(196°)
Lobe Center: ---------------- 108°(108°)---------108°(108°)

Intake Opens 4.5° (-10°)BTDC Exhaust Opens 40.5° (26°)BBDC
Intake Closes 40.5° (26°) ABDC Exhaust Closes 4.5° (-10°) ATDC

Valve Timing Is Checked With Zero Valve Lash @ 0.050 Inches Of Valve Lift.
Comparison Chart:
http://www.vwparts.net/mm5/merchant.mvc ... webcamt4ch

My question is can anyone explain what is happening in the engine?



I can see that the 107i lifts higher and sooner and for a longer duration, (the Raby 9550 has a little less lift for a longer duration) but I am not understanding the why's and wherefores.

What makes the 107i 'good for overall performance'.

Mine runs great on the open road but does not like the spec'd idle (ie at spec idle, 950ish, the vacuum is waaay down) but will perk right up with 100-200 more rpms.

Also, Why do the webcam hydro lifters instruct to set .5-1 turns as opposed to (1.5-2 turns)?
Geoff, I am hoping that you can give some of your insight here...

no experience cookin' up an engine, but have a grasp on whats going on.

longer duration and lift let more air fuel into and out of combustion chamber.

there is an optimum size difference between the intake and exhaust valve size, exhaust being smaller. seems counter intuitive to me but science has proven it.

lower lift will increase velocity into the chamber.

longer duration and valve overlap have to have the airflow to support it. think about match porting intake manifolds to exactly match the ports in the head. some high duration cams have valve overlap, both valves open at the same time. for them, you have to bump the compression ratio up to compensate. once in this territory you have to think about head porting and better induction. carbs or modern EFI, with a bigger throttle body. you also have start considering a tuned exhaust.

I have a type 1 built like this, in my buggy, anibal chico of cpr engines built it. 2275 cc, dual weber 44 idf's, engle 120 with ratio rockers. mini D-port on stock heads, oversize valves, estimated at 175 horsepower. every thing in that engine is part of a known recipe for a combo that works.
i've been thrashing this engine for 5 years now with nothing but maintenance done to it. buggy with me weight 1500# + 175 hp = stoopid fast

point being that mine doesn't idle at 900-950 either real happy at 1000. bump yours up

have you ever heard a radical v8 idling real bumpy? they call it loping. its because the cam is so radical that the engine doesn't come alive until it achieves the flow needed for the cam design, then its hang on time.

On the hydro lifters, different manufacturers engineered their own way of doing things?

















[quote][/quote]

Thanks vdubya.

This helps. More data to process.

I have liked the higher idle rpms in the past anyway.

One of the issues I struggle with is the automatic transmission. If I were to offer an opinion about a cam choice with an automatic, I would suggest sticking close to stock to avoid having to have a higher idle speed.

at 1200 in Park or Neutral I am in the 1000 zone in Drive. Quite a bump when she engages.

I have a balancing act om my hands. just have to deal.

Ran nice today. Working on being light on the accelerator pedal to maximize city mileage.

I have a 200 mile round trip planned for this weekend. Can't wait.

Bleyseng wrote:

vic74 wrote:Thanks for link Bleyseng-I like the way that the Raby components are sold in comprehensive kits. Helps to eliminate a bad part choice by a newb like me! His expertise is worth a lot for sure if I go with a non-stock option. People seem to be consistently happy with his stuff.

Thanks for the CB "econo cam" recommendation. What improvements did you notice? Looks similiar to the web 73 I'm also considering. Sounds like your pretty happy with it and it might work with stock solexes which I may use. I'm wondering if either of these cams would help lower CHT's or otherwise benefit a loaded westy.

I don't plan on keeping the progressive permenately, but I hope I can break in the engine with it. I doesn't work great in the winter but does pretty well the rest of the time (at least with the stock cam). I have some stock solexes that need to be re-bushed/rebuilt, and'm I'm assuming re-jetted for a 2.0. I'm also considering dual webers-but I don't want to have to set up dual carbs at the first start up. Thanks for the input so far.

The Raby cams have his special exhaust valve timing duration so that CHT's go down. The Web73 and I'd guess the econo cam have the same as stock exhaust duration but different than stock intake lifte and duration.

Rabys cam has a split duration on the exhaust side. The intake & exhaust duration on the Web 73 differs from the stock set-up slightly. Both are far better than stock so long as their coupled with better than stock flow heads. I'm running (2056cc) 42x36 heads with my Web 73 and it's drive ability is better than the stock set up and runs cooler. And that's even with my German 009 tweaked.

If you are using the stock Ljet there are limits to what it will tolerate in regards to the valve overlap. This injection likes a good vacuum signature at low rpms to produce a good idle. The intake duration and lift is increased to get better flow and fuel charge and a bigger valve than the stock 37mm helps too. More fuel = more power. Exhaust is limited by the muffler set up so the duration isn't changed much and again a slightly larger valve helps. The exhaust charge is also pushed out by the fuel burn so the valve is smaller than the intake valve. Raby has the duration timing set longer to get more heat out of the exhaust valve when its seated and also when its open IIRC to allow more exhaust to leave. That's why he wants everyone to use a better than stock muffler, 72-74 HE's to utilize the better exhaust valve timing to lower CHT's. Meaning get the heat out of the head and out of the engine more efficiently. Better intake charge and better exhaust removal means more hp and cooler temps but you are really limited in what can be done due to the Ljet. These are small changes but the results are a cooler running than stock setup equals longer engine life with more hp and torque. With hydro lifters the ramps of the cam are different but its the same principle. Open longer and higher intake and open longer and higher exhaust than stock but it still affects the idle. For the best idle stick with a stock cam if you have a auto tranny or you have to live with a higher idle and the off idle "bump".

Geoff,
well put. Thank you.

I can confirm, through my recent experience with the Webcam 107i, that the idle struggles and the increase in idle speed I am using to overcome the low vacuum and 'loping', combined with the Auto tranny, are contributing to the parts having trouble playing nice together.

Live and Learn...

72Hardtop wrote:Rabys cam has a split duration on the exhaust side. The intake & exhaust duration on the Web 73 differs from the stock set-up slightly. Both are far better than stock so long as their coupled with better than stock flow heads. I'm running (2056cc) 42x36 heads with my Web 73 and it's driveability is better than the stock set up and runs cooler. And that's even with my German 009 tweaked.

I need some definitions and proofs here.

What is your definition of "split duration on the exhaust side".

What is your definition of "driveability better than stock" "even with your 009 tweaked"?

I have some comparative experience with dual carb engines and fuel injected engines and Raby engines and others.
Colin

Gypsie wrote:Geoff,
well put. Thank you.

I can confirm, through my recent experience with the Webcam 107i, that the idle struggles and the increase in idle speed I am using to overcome the low vacuum and 'loping', combined with the Auto tranny, are contributing to the parts having trouble playing nice together.

Live and Learn...

Let's also remember that if you extend the exhaust valve duration, you are immediately hampering its ability to shed heat.

I am discouraged with watching these poor L-Jet modified-cam engines unable to obtain a decent idle because there is no friggen airflow. My stock engine has a steady idle down to 550 rpm and pulls right off. I do not use the upper rpms but for an occasional on ramp.
Colin

If extending the exhaust valve duration hampers the ability to shed heat - wouldn't those 9550 Raby cam's make things run hotter Vs the cooler temps that most report seeing using them?

It would be a little annoying to have a poorly idling motor, but if the trade off is more power, lower CHT's and retained fuel economy - eh. I guess if you do mostly highway vacation driving it would be an easy trade off. I do most of my driving around town and a crappy idle wouldn't be worth it to me.

Amskeptic wrote:

72Hardtop wrote:Rabys cam has a split duration on the exhaust side. The intake & exhaust duration on the Web 73 differs from the stock set-up slightly. Both are far better than stock so long as their coupled with better than stock flow heads. I'm running (2056cc) 42x36 heads with my Web 73 and it's driveability is better than the stock set up and runs cooler. And that's even with my German 009 tweaked.

I need some definitions and proofs here.

What is your definition of "split duration on the exhaust side".

What is your definition of "driveability better than stock" "even with your 009 tweaked"?

I have some comparative experience with dual carb engines and fuel injected engines and Raby engines and others.
Colin

Well the split duration is what Raby offers in his cam as he's already confirmed many times. As for the 'Driveability' I compare that to the stock dizzy I chucked years ago when jumping to the dual Webers. Keep in mind my German 009 is nothing close to the crap 009's laying around these days and it's been tweaked a bit. I'm also not using a stock T-4 cam either. Running Web 73 with Web solids. Mine idles better from a cold start and that's without those crappy Solex carbs that won't hold a synch after 30,000 or so miles due to the bushings wearing out in them.

I have learned over the course of 30+ years of owning and working on my bus is that there is better out there. The problem these days is that it's not getting easier but harder due to the availability of quality parts. Couple that with the dwindling number of competent builders and you have a recipe for disaster waiting to happen.

72Hardtop wrote:

Amskeptic wrote:

72Hardtop wrote:Rabys cam has a split duration on the exhaust side. The intake & exhaust duration on the Web 73 differs from the stock set-up slightly. Both are far better than stock so long as their coupled with better than stock flow heads. I'm running (2056cc) 42x36 heads with my Web 73 and it's driveability is better than the stock set up and runs cooler. And that's even with my German 009 tweaked.

I need some definitions and proofs here.

What is your definition of "split duration on the exhaust side".

What is your definition of "driveability better than stock" "even with your 009 tweaked"?

I have some comparative experience with dual carb engines and fuel injected engines and Raby engines and others.
Colin

Well the split duration is what Raby offers in his cam as he's already confirmed many times. As for the 'Driveability' I compare that to the stock dizzy I chucked years ago when jumping to the dual Webers. Keep in mind my German 009 is nothing close to the crap 009's laying around these days and it's been tweaked a bit. I'm also not using a stock T-4 cam either. Running Web 73 with Web solids. Mine idles better from a cold start and that's without those crappy Solex carbs that won't hold a synch after 30,000 or so miles due to the bushings wearing out in them.

I have learned over the course of 30+ years of owning and working on my bus is that there is better out there. The problem these days is that it's not getting easier but harder due to the availability of quality parts. Couple that with the dwindling number of competent builders and you have a recipe for disaster waiting to happen.

I recently bid farewell to my '73 bus with factory dual carbs and stock distributor at 558,238 miles. Its travels are documented here in the Itinerary forums and on theSamba dating back to 2003. Driveability rivalled fuel injection. Some members here drove that car, and they too can attest to its beautiful smooth manners.

I think many of our discussions and opinions have to be filtered through our personal experiences, i.e. in my experience, correctly set up stock Solex PDSIT carbs and that 205j distributor are damn close to perfect . . . I enjoyed mine for thirty years eight months and eleven days.
Colin

airkooledchris wrote:If extending the exhaust valve duration hampers the ability to shed heat - wouldn't those 9550 Raby cam's make things run hotter Vs the cooler temps that most report seeing using them?

CHT temps tell you what is happening at the plugs.
Nobody has a gauge that reads exhaust valve face temps.
The combustion temps can be perfectly normal when you burn an exhaust valve,
its failure is a localized trauma that only the valve metallurgy can tell you.
I have not heard of exhaust valve failure in Raby engines due to excessive open duration. But I ask about long duration exhaust valve seat time because I am curious.
Colin