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Sun Sep 21, 2014 8:53 pm

I'm putting together a 1600 single port and have the following so far....

Stock case, crank, p&c's
Dual webber 34ict's or kadrons (have both)
Trimil euro exhaust

Curious about which cam would work best for this combo. W100, c25, c35, w110, ?,?

Going into a 64 beetle

Sun Sep 21, 2014 8:55 pm

engle 100 or milder.

Sun Sep 21, 2014 9:30 pm

How do the c25 and c35 compare to the w100

Sun Sep 21, 2014 10:06 pm

C25 ~ W100.
C35 ~ W110.
C45 ~ W120

Mon Sep 22, 2014 8:20 am

why do the c35 numbers appear to be closer to the w100, yet most of what i read lists it as almost identical to the 110? is the duration what makes them so similar?

c35 specs
.381" Cam Lift, .420" Valve Lift (1.1 Rockers) 285 degrees of advertised duration

w100 specs
.383" Cam Lift, .420" Valve Lift (1.1 Rockers), 276 degrees of advertised duration

w110
.392" Cam Lift, .430" Valve Lift (1.1 Rockers), 284 degrees of advertised duration

Mon Sep 22, 2014 9:11 am

Don't go over 236° @ .050". They get way too lumpy and loose a bunch of low end. I just did a 1915cc with a 218/119 (242° @.050"), and Kad's. It was too much duration. I should have just done a w100 w/ 1.25 rockers on the intakes only.

Brian

Mon Sep 22, 2014 9:24 am

Youre comparing lift alone. That does not tell you the whole story. you need to look at the lift @ 0,050" to get a better picture.

Until about 10 - 11 years ago I was using a lot of C25´s in mild engines. Then it was sort of superceeded by newer, better grinds. I never cared much for the C35 apart from a couple of very specific builds. There are so many better choices out there. The C45 however, that´s a VERY nice cam for a medium sized nippy engine.
In your case it would be way too much.

CB 2280. Good steady idle, good midrange power. Good fuel efficiency potential.
Engle W100. Slightly lumpy idle, decent midrange, more upper end power.
CB 2239. A tad better idle quality than the W100, in a sgl. port engine the power difference is minor between the W100 and the 2239.

T

Mon Sep 22, 2014 12:11 pm

Cheater cam...

http://www.cbperformance.com/ProductDetails.asp?ProductCode=2280

Casey

Mon Sep 22, 2014 2:54 pm

Brian_e wrote: Don't go over 236° @ .050". They get way too lumpy and loose a bunch of low end. I just did a 1915cc with a 218/119 (242° @.050"), and Kad's. It was too much duration. I should have just done a w100 w/ 1.25 rockers on the intakes only.

Brian

Brian, have your SP heads been ported or larger valves installed?

Mon Sep 22, 2014 4:22 pm

youngnstudly wrote: Brian_e wrote: Don't go over 236° @ .050". They get way too lumpy and loose a bunch of low end. I just did a 1915cc with a 218/119 (242° @.050"), and Kad's. It was too much duration. I should have just done a w100 w/ 1.25 rockers on the intakes only.

Brian

Brian, have your SP heads been ported or larger valves installed?

I spent way too much time on the heads. They are stock valves, but I did a ton of work to the intakes. I filled the 6mm studs, and redrilled 8mm studs with the same spacing as the exhaust flanges. I also filled the sealing ring recess, and then milled everything flat. I didn't use a gasket, just Motoseal. Lots of careful porting and bench testing. The inlet hole is now 31.5mm. I managed to get 123cfm @28" .450" with the fancy custom manifolds and Kadrons bolted on.

Mon Sep 22, 2014 9:02 pm

Sure looks nice! Bummer about the cam. I gathered almost all the parts for the same exact 1915cc single port build almost 4 years ago, and I have been thinking about ditching the 218/119 cam (on a 112 LC) that I originally bought for it. The difference in my engine is the heads will have 37x35mm valves and are getting professionally ported....what I mean to say is I've been waiting on them for 3.5 years now to get finished. :?

I don't want to just throw any old cam into this build as I think it would really do well with a split duration cam, but I'm really not sure which way to go. In reality, I need gas mileage at this point and should stick to a more mild camshaft...but I can't help thinking about the possibilities.

Did you end up using a lightened flywheel? Thanks for the input, my brain is putting in overtime now. I haven't given any thought to this engine in a few years since I don't have the heads yet (plus I have a ton of other stuff going on right now). :)

Andy

Mon Sep 22, 2014 10:14 pm

Alstrup wrote:

CB 2280. Good steady idle, good midrange power. Good fuel efficiency potential.
Engle W100. Slightly lumpy idle, decent midrange, more upper end power.
CB 2239. A tad better idle quality than the W100, in a sgl. port engine the power difference is minor between the W100 and the 2239.

T

^^As usual Very good advice!

In the siamese port engine you have a period when both intake valves are open. This can be a problem but it is no disadvantage up to 40 degrees of overlap.
I "think" past approx 60 degrees overlap between intake valves, there is point of diminishing returns, cylinders 2 and 4 lose more than 1 and 3 gain.

This works out to 220-240 degrees at .050

Another idea is the fk-41. while it is said to be for high ratio rockers, quite a few folks have run it with 1.1 or 1.25 ratio in smallCC engines with good results.

Mon Sep 22, 2014 11:05 pm

Andy, I for one, have never tried the 218/119 in a sgl port and therefore not 112 LC either. Off hand I would expect the split to be on the low side, and then idle quality will suffer somewhat, along with fuel efficiency. But that is pure speculation.
If fuel efficiency is paramount, i would definitely try the 2228 (2280 on 112 LC)

That said, in extention to Modoks reply with FK series cams. I have tried a FK42/41 with 1,3 rockers on a 1914 with set of stock valved sgl port heads. On that I managed to pull 108 hp @ 5000 rpm. and 160 Nm torque. Same engine with a set of heads with 37,5/33 mm valves pulled 114 hp @ 5100 and 162 Nm peak torque. The "large valved"heads made LESS torque below 2800 rpm. but more torque above 4000 rpm.

So, IMHO a good amount of split duration can work very well.

T

Tue Sep 23, 2014 6:36 pm

A nice split duration cam I've seen used as a stock replacement is Crower's 61002.
http://www.crower.com/cam-card-finder/

Thu Sep 25, 2014 11:48 am

any thoughts on using an FK65?

it's been suggested that this might also be a great choice for my build even without using higher ratio rockers?

how would it compare to the w100 (with SP heads)....?

Fri Sep 26, 2014 2:37 am

Personally I do not like the FK65. In your case I would stick to the w100, with 1,25 rockers on intake. That will give you more usable power.

Fri Sep 26, 2014 11:03 pm

Alstrup wrote: Andy, I for one, have never tried the 218/119 in a sgl port and therefore not 112 LC either. Off hand I would expect the split to be on the low side, and then idle quality will suffer somewhat, along with fuel efficiency. But that is pure speculation.
If fuel efficiency is paramount, i would definitely try the 2228 (2280 on 112 LC)

That said, in extention to Modoks reply with FK series cams. I have tried a FK42/41 with 1,3 rockers on a 1914 with set of stock valved sgl port heads. On that I managed to pull 108 hp @ 5000 rpm. and 160 Nm torque. Same engine with a set of heads with 37,5/33 mm valves pulled 114 hp @ 5100 and 162 Nm peak torque. The "large valved"heads made LESS torque below 2800 rpm. but more torque above 4000 rpm.

So, IMHO a good amount of split duration can work very well.

T

Torben, thank you for the insight and suggestions. I am thinking that the 2228, w100, or Fk42/41 will be better choices for my single port build, and I'm really considering the FK42/41. Originally I was after power, but I would rather have something that drives a little smoother in the lower RPM range (and hopefully gets better MPG too).

I wish I would have stuck with stock valve sizes and just used a "smaller" cam like the Engle 100. The larger (37x35) valved heads should really use a more aggressive cam to take advantage of the additional valve size and porting.

Did you use dual springs with the FK42/41 in your single port 1915, or single springs? Also, what lobe center would you recommend using with my setup? Thanks again.

-Andy

Sat Sep 27, 2014 1:01 am

I used Scat sgl HD springs, shimmed 1 mm to get 1,45" installed height.

Normally dual springs are needed with these cams, but the sgl port engines dont rev that high. No need and no cause to rev it past 5700 rpm.

T

Sat Sep 27, 2014 2:39 am

IMO the fk-42 is too much duration(intake overlap)

maybe fk-41 with 1.25 rockers on intake and 1:1 40 horse on exhaust.

Sun Sep 28, 2014 7:59 am

This is exactly the type of insight I was hoping for.

Are you saying just use the 1.25's on the intakes and use stock rockers on the exhaust?
I didn't even know you could or should mix and match. Does it matted which shafts are used (rocker Shafts)?