New Heads and 1.25 Rockers?

[Brian_e]

Correctly sized and correctly built heads will get you much farther than a set of 1.25 rockers. The 218 with stock rockers is right close to .460" lift.

You might be able to get away with the bolt-on style 1.25's, because they only lift 1.18 in real life. Most of the wiper style 1.25's are closer to 1.3 ratio, which I would never do on a 218.

Why not pull your heads, and have a 37mm intake installed, and have them properly ported? This would be the best of everything. To big of heads on a small engine with a mild cam is no fun to drive. Just as the heads start working, the cam is about done....

Brian
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[vdubrookie]

posted by mistake

[Brian_e]

[Alstrup]

I love it when you talk dirty But I totally agree on the Scat rockers.
I also agree that in a bus that is set up like Mikes my first choice would be a well made set of 37,5 x 32/33 valved heads. The 218 cam is perfect along with such a combo.
If you decide on the P heads after all I would leave out the 1,25´s to keep lower rpm torque best possible with that transmission.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[mikelars]

Ok, so let me write out my full modification here:

Current Engine:
74x90.5 = 1904
218 WebCam
Dual Weber 40 IDF with 28 vent and 1.15 main
1.1 rockers
AA500 DP heads 35.5/32
Performance Heater Boxes 1 1/2
Vintage Speed SuperFlow 155-706-052SF

Modification for Fall 2021:
74x90.5 = 1904 (same)
218 WebCam (same)
Dual Weber 40 IDF with 32 vent and 1.3 main
1.1 rockers (but could “try” 1.25 because the 218 supposedly “can” use 1.25)
Panchito heads 40/35.5
Performance Heater Boxes 1 1/2 (same)
Vintage Speed SuperFlow 155-706-052SF (same)

Looking to go from about 85HP to 115HP without losing too much low end…. Not sure how fuel economy will suffer with new setup…

I know there have been a few suggestions to use 37/32 or just port the AA500s, but I just want something I can buy out of the box, and swap in without taking the bus out of commission for weeks. I don’t know where to get porting done or how long it would take, so it seems easier to swap in the Panchitos and sell the AA500s.
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[vdubrookie]

Made new post

[sled]

as mentioned previously, Steve Tims has 37x32 hand ported heads available.

https://www.thesamba.com/vw/classifieds/detail.php?id=1069091

as also mentioned, I would personally stick with the stock rockers (with elephant feet) on the 218




the 1968cc that Brian_e mentioned previously went into one of my customer's buses...it hauled the mail plenty of torque down low and didn't run out of steam till 'plenty fast'.

37x33 hand ported heads
218 cam with stock rockers
.040 deck
8.8:1 compression
1-1/2 heater boxes
A1 sidewinder exhaust.
40 idfs with I believe 32 chokes.

lots of good advice previously in this thread, I would heed it.
_________________
drive your split.

[Brian_e]

Since the OP is set on buying panchitos, rather then other heads that would be near perfect, why don’t you make the rest of the engine better suit the new big heads?

While you have the heads off, add a new set of AA 94mm A pistons and cylinders with grant rings. Then you will have a 2054cc, WAY more power, and the displacement will then start to match the larger heads. The 218 with stock rockers will still work fine.

Brian
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www.type-emotorsports.com

[mikelars]

Ok - well I haven’t bought the Panchitos yet, so it isn’t a done deal. I can probably still be convinced…. The ones you say would be near perfect are either the ported 37/32s or else the ACN L3s?

If I go with those and I leave the 218 with 1.1 rockers - should I bother to change the Venturi / main jet to 32/1.3 or just leave at 28/1.15?

I am not set on the Panchitos - but just thought it wasn’t a bad choice to get the bigger valves. Now I am starting to feel like most folks agree that the smaller valves with porting would suit me better.

I was not planning to open the case, since my 1904 setup is running well and just broken in at 10k miles…
_________________
Here is my 1961 Beetle Restoration:
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Here is my 1966 Split Bus - Restoration Channel:
https://youtube.com/channel/UCPBRysmvrJlif2wzwEwiuwQ

2332 Torque Motor Build
https://youtube.com/playlist?list=PLW_2wBCs4Ny2HwsKM9QT4LFpcSqP3QG0p

Engine Rebuild 1968cc Playlist:
https://youtube.com/playlist?list=PLW_2wBCs4Ny1JbZ2EgJQQ2awfo0koZRqz

[mikelars]

Ok, I contacted Steve Tim’s about the Super Stock 37x32 heads.

Sounds like I could get these and either leave everything else the same, or up the Weber’s to 32/1.3 along with these heads…
_________________
Here is my 1961 Beetle Restoration:
https://www.youtube.com/playlist?list=PLW_2wBCs4Ny2qXEPvdnfvEzN42T8JA8zO

Here is my 1966 Split Bus - Restoration Channel:
https://youtube.com/channel/UCPBRysmvrJlif2wzwEwiuwQ

2332 Torque Motor Build
https://youtube.com/playlist?list=PLW_2wBCs4Ny2HwsKM9QT4LFpcSqP3QG0p

Engine Rebuild 1968cc Playlist:
https://youtube.com/playlist?list=PLW_2wBCs4Ny1JbZ2EgJQQ2awfo0koZRqz

[Brian_e]

Trim the bases of the 94mm cylinders down to slip into your current case. No need to open the case. Been done lots before.

The L3’s are pretty much exactly what you have. No porting on an AA casting with 35x32 valves.

You should be running at least 30mm vents.

The other cheapest option is to doll up your current heads and have a real valve job done on them at a local shop. You can pick up about 10-20cfm easy with some blending and a correct valve job.

Brian
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[Teeroy]

I would leave the 28mm vents no matter what you choose to do with the rest, you want torque and good throttle response not high rpm horsepower in a bus. I have a big valve 1776 in my beetle with 32 vents in 40 IDFs, all jetted and dialed in, will pull to 7000 rpm but very poor low end. Put said 1776 in my bus will I freshened up its 2007, was not a good combo. I would leave your combo alone and only change the heads (send your to Brian to rework or a set of Tims ported Super Stocks). When I finally dyno my 1776 this fall, I'm gonna pull it apart for refresh and change heads and drop vents to 28 and rejet
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ARR #3
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[mikelars]

Doing more research - looks like CB’s 1179 Builders Choice puts Panchito 44s on a 1904. They just use a different cam than I have.

https://www.cbperformance.com/product-p/1179.htm

So it seems that some people do use 40/35.5 on a 1904.
_________________
Here is my 1961 Beetle Restoration:
https://www.youtube.com/playlist?list=PLW_2wBCs4Ny2qXEPvdnfvEzN42T8JA8zO

Here is my 1966 Split Bus - Restoration Channel:
https://youtube.com/channel/UCPBRysmvrJlif2wzwEwiuwQ

2332 Torque Motor Build
https://youtube.com/playlist?list=PLW_2wBCs4Ny2HwsKM9QT4LFpcSqP3QG0p

Engine Rebuild 1968cc Playlist:
https://youtube.com/playlist?list=PLW_2wBCs4Ny1JbZ2EgJQQ2awfo0koZRqz

[sled]

of course they do, and some people probably even use 42x37. Does that make it better? not necessarily.

CB doesn't even sell heads that have smaller than 40x35 valves, so it makes sense they would offer panchitos on a 1904.

if you really want to stick with the 1904, then I really think some nice 37x32 heads and 30 chokes in your carbs would be good. If you're willing to up the displacement, then the panchitos would be the logical choice.

no one is trying to sabotage your engine and make you unhappy with the outcome
_________________
drive your split.

[Paul.H]

Only reason I built my 1904 with big valve heads is because that's what I had lying around not something I'd choose to build from scratch. Maybe if you had a 1776 with a duff crank and chunky rods you'd could slip a 74mm in there otherwise it'd be a 2017

[Brian_e]

Ok..here are some numbers for you. These always seem to help people understand the iportance of correctly sizing the valves.

These numbers are all based on a 88% valve to throat ratio, which the panchitos have, and usually what I shoot for on a street engine.

A 1904cc with a 35mm valve should rev to 5376rpm before being choked by the valve seat cross sectional area.

1904cc with a 37mm valve will rev to 6036rpm

1904cc with a 40mm valve will rev to 7074rpm

Now that you have seen the numbers, you need to sit down and decide how high you honestly want to rev this engine. Since your cam is perfect for what you are wanting, it should stay. The 218 is an amazing cam, but it is on the shorter side of duration. In a 1904cc engine, it will be running out of steam around 5800-6000rpm.
Since the cam runs out of steam around 6000rpm, there is no reason to have heads that will be working up into the 7K RPM range. The ultimate engine combo will have ALL the parts matched to one specific RPM range where it will be used.
Ideally all the parts will start making power, and quit making power all at the same time. If you can achieve this, it will have a wide, and very powerful powerband, and then fall on its face at your designed upper RPM limit.

Hope that makes some sense.

Brian
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www.type-emotorsports.com

[mikelars]

ok - I think I am leaning toward the 37/35.5.

Since the cost is similar, I just want to make sure I don't wish I had bought the 40/35.5 down the road.

I am not totally sure how much more performance I would get out of 37/32 ported versus Stock 35.5/32, but it sounds like it can make a bigger difference than the valve sizes suggest - due to the porting.

Getting info on the 37/32 from Steve Tims...

Thanks all...
_________________
Here is my 1961 Beetle Restoration:
https://www.youtube.com/playlist?list=PLW_2wBCs4Ny2qXEPvdnfvEzN42T8JA8zO

Here is my 1966 Split Bus - Restoration Channel:
https://youtube.com/channel/UCPBRysmvrJlif2wzwEwiuwQ

2332 Torque Motor Build
https://youtube.com/playlist?list=PLW_2wBCs4Ny2HwsKM9QT4LFpcSqP3QG0p

Engine Rebuild 1968cc Playlist:
https://youtube.com/playlist?list=PLW_2wBCs4Ny1JbZ2EgJQQ2awfo0koZRqz

[mikelars]

I meant 37/32 from Steve Tims...
_________________
Here is my 1961 Beetle Restoration:
https://www.youtube.com/playlist?list=PLW_2wBCs4Ny2qXEPvdnfvEzN42T8JA8zO

Here is my 1966 Split Bus - Restoration Channel:
https://youtube.com/channel/UCPBRysmvrJlif2wzwEwiuwQ

2332 Torque Motor Build
https://youtube.com/playlist?list=PLW_2wBCs4Ny2HwsKM9QT4LFpcSqP3QG0p

Engine Rebuild 1968cc Playlist:
https://youtube.com/playlist?list=PLW_2wBCs4Ny1JbZ2EgJQQ2awfo0koZRqz

[Brian_e]

Some flow bench numbers for you to look at. Measured on my Audie Tech dual motor flow bench, 28" with a matching IDF manifold with a radius inlet.

Port volume is more important than flow numbers, but this will give you an idea of what the larger valves can do.

Your out of the box AA500 35x32 heads = right near 120cfm @.500" lift

My ported AA500 35xx32 heads = about 135cfm @ .500"

My ported AA500 37x32 heads = about 155-160cfm @ .500"

Non-cnc panchito's = about 145cfm, and choked about .450" lift.

Brian
_________________
www.type-emotorsports.com

[chrisflstf]

Its hard to give up the idea that bigger is always better, but in this case, I would follow Brians advice. He definately knows how to build good, proper working and functional motors. My 2 cents.