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raising compression and increasing valve size in 2L kombi
tom_1973 - November 16th, 2005 at 02:30 PM

Hi all,

my mechanic, who I trust, reckons that by using premium u/l, increasing cam lift (by a little - a mild cam apparently), increasing valve size and raising compression can radically increase the hp of the engine.

Anyone had any experience with this?

My concern is that by raising the compression it'll shorten the life of the engine.

Should it increase or decrease economy?

Any experiences greatfully heard.

Cheers,
T


barls - November 16th, 2005 at 02:41 PM

ill let you know as i put a mild cam in my t4 powered bug


Bizarre - November 16th, 2005 at 02:55 PM

I would agree with you mechanic

I have done similar in my 1982 2L air cooled bus.
Cant quote figures but it is happy after 50,oookms in 3 odd years from rebuild

It is also the logic behind my type 1 motors.

Compression goes up say....to 8:1 maybe a tad over
A mild cam (AP2 or Engle 110 etc etc)

I would also improve carburation
Say dual Webers over the PICTs

Done properly it will increase HP, improve economy and make negligible difference to longevity

The compression increase and cam are bugger all in cost.
Cam is a cam in cost and you need (should) to machine your heads anyway. It is just how much you fly cut the heads.

The valve increase can be a cost.
I have not done this. But i did get a 3 angle valve job when they machined the heads


pete wood - November 16th, 2005 at 03:23 PM

um, my bro had 1800 heads put on his 2l when it was rebuilt. Apparently they have larger valves. Also raises the compression a bit too he reckons. Can anyone confirm this?


barls - November 16th, 2005 at 03:23 PM

i can recommend vforces mild cam as thats what i put in. it was a good price about $200 with a full set of lifters i think but give richard a call any way


Andy - November 16th, 2005 at 03:51 PM

http://www.tunacan.net/t4/tech/heads.htm#aftermarket 

Not that I've done any such work myself, but 2L heads apparently "flow better" depite the smaller valves (they have a different combustion chamber shape).
Also consider twin plug heads, they seem to get good reports, and not a huge cost mod if your already getting head work done.

Just remember if it's going back into a kombi, a good flat torque curve from low revs is better to drive than high HP.

Have a good search through past posts, this has come up often before.
:thumb


Menangler - November 16th, 2005 at 05:43 PM

I ran a "hottie" 2ltr in by old '77 delux micro.
It used a European "E" grind cam, (like an Engle 120)
flat top Beetle 94mm "B" pistons on modified 2 ltr rods,
stock 71mm crank, 1800 heads, twin 44 idf Webers, Quiet Thunderbird exhaust, it had 8.5 to 1 compression, ran cooler than stock, gave 25 + miles per gallon on a trip and made around 110hp, up from the standard 70 ish of a stock 2 ltr. It did 130,000 kms before I pulled it out to sell the car.
If anyone wants a similar engine, I will have one 4 sale in a few weeks, complete ready to bolt in.