Stock cam with 1.4 rockers or mild cam

[Scrapefest]

Hi, I am in the UK and have a '69 Bay microbus that I use for camping and take on longish journeys.

My first engine setup was
1600cc
New dual port heads stock valve sizes
Stock cam with 1.25 ratio rockers
Twin 36 Weber IDFs
SVDA Bosch distributor
Stock exhaust
Stock 3 rib trans

This drove very nicely from idle and had a noticeable increase in power

I have since changed the exhaust to this

I would now like more power the simplest way seems to be rebuild it into an 1835cc and change the cam. But could a stock cam with 1.4 rockers be as good or better than a cam change?

Would there be any disadvantages of using 1.4 rockers on a stock cam compared to a mild cam with stock rockers, what valve spring setup would be needed.
I would like smooth power from idle and good fuel economy.
What revs would you expect the engine to have power up to.

Thanks
Andy

[early]

Wondering if you happen to check the head chamber capacity of those AA500 heads before installing.
I was thinking they were like 60cc which would make for a really low compression 1600. Like 6.7:1. Which could be the problem you are having.
I might be mistaken on that 60cc number but when I was looking for stock heads for a 1600 I built last summer I passed on the AA 500 stock heads for that reason. I ended up getting the stock autolinea heads from CB which were 50cc chambers.
As for the other upgrade questions, I'm currently building an 1835 for my split window bus which others here have suggested.
_________________
early-
Barnfind westy project
https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=
my 73 sports bug project build
http://www.thesamba.com/vw/forum/viewtopic.php?t=497088
Current Projects :
73 Sport Bug - L13M gone now
67 Westfalia
57 oval window ragtop - sold june 2021
61 sedan
68 Corvette Roadster - Small Block, 4 Speed
86 GMC Sierra Classic- 4x4, Shortbed
94 Harley Flstn

[Scrapefest]

I built the engine roughly ten years ago so I don't have any notes . regarding compression Ratio, I would have checked it . I don't remember it being lower than stock. It does have more power than other buses I have driven a 1700 type 4 that was a dog compared to mine.

Are you saying it falling on its face is due to low compression, I was wondering if it was due to the stock cam running out of revs or the ports or valve springs.

Has anyone got experience of a stock cam with 1.4 rockers?

[MuzzcoVW]

[Scrapefest]

Ok I have edited the original question to get it to the point I was asking. The engine doesn't run badly and I didn't slap it together, it is just time for more power.

Thanks.

[vwracerdave]

Yes you can put 1.4 ratio rockers on a stock cam but the cost of the new rockers plus the correct length push rods will never be worth the very tiny gains in power. If you are planning to put in 92's then split the cast and get a new cam.
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[rosevillain]

My current driver has 1.4 rockers and a stock cam. I didn't want to split the case, but I wanted more smiles. Single port, dual carb, cheap header. I'd do it again for a driver that I didn't want to build from scratch. I think that this engine will rev until it scatters in a bug.

[Scrapefest]

[Scrapefest]

[Alstrup]

STAY AWAY from the C25 It is about the lousiest cam on the market, at least for now. Totally useless.

Since you have very little idea about where your current engine falls off it is a little difficult to determine what is the reason, - if there is any.
One obvius is that muffler. It is ok for a stocker, but not much more than that. the next is probably timing and fuel. If it runs lean it will not make power. A low compression engine will typically rev, but not pull much.

The 1835 solution is a good option for a bus. Thw W100 is fine for what you want to build. - Yes "we" prefer other cams, but the W100 is not a bad cam for the segment.
As always, the power is in the heads. The AA500´s aint bad out of the box, but if you want decent power out of an 1835 withém they need a little help. Correcting the seats and strategic touching the ports and chambers.
Get a proper muffler If you are not into VS (Which would be my choice for such a vehicle) you can use a regular 1 3/8" header but make yourself a better muffler for it.
A well built 1835 bus engine built around the parts mentioned can easily be around 100 hp and 160ish Nm torque.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[rosevillain]

[Scrapefest]

[Scrapefest]

[mikedjames]

If you get the power up enough with a big engine you will then risk being able to fry the engine even better than with a stock 1600 ..


I have to watch the gauges as the stock cooling gets overwhelmed at a steady 65mph with a 1641 with a progressive and a single quiet pack and crank fire ignition..
With the AFR sitting at 12.5:1 on the gauge, and the timing on the gauge at 28 degrees WOT or 29 degrees slightly off WOT.
_________________
Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Alstrup]

[Scrapefest]

[dgsaz]

It's a shame Aircooled.net is no longer in business.

I used their L-3 heads, 1.4 ratio rockers, pre cut pushrods that only worked if you were replacing stock rocker arms with 1.4s.

They fit and worked great.

I'm sure the heads made more of a difference than the ratio rockers.

I added a pair of IDF 40's to the stock internals 1776 and the combo is sooooo
much stronger than when it was a single port.

Dub Dyno gives it 89.9 HP based on this combo.
dgsaz

[MuzzcoVW]

[Rob Combs]

The only reason I can think of to put 1.4s on a stock cam is if you are absolutely unwilling or unable to down the vehicle long enough to split the case. Racerdave is exactly right on this. Easy to drop upwards of $500 on rockers and pushrods if you go with Berg (~345 on the rockers, and 100+ on pushrods, then shipping, and depending on where you are, taxes & duties too). There are cheaper ways from other vendors whose parts may be just fine and set up easily enough. But once you're done you'll barely notice the difference, all other things being equal.

Been there, and that's been my experience.

Split it, cam it, and build it back right using the information some of our brilliant builders have shared with us, if you are willing and able. Less disappointment that way...

[Scrapefest]