Skip to content
Aussieveedubbers

Unleaded v leaded engines

0 likes
Share Share on Facebook Share on X Share on Reddit

squizy Thinking about another dub...maybe

4,082 posts · joined Dec 2002 ·

#276360
My cab is running a factory unleaded setup. What is it that allows a VW motor to run on unleaded. Is it the compression ratio of the motor, different cylinder heights etc etc?

Just curious I suppose, given that sometime in the future we may all have to do some sort of mod to our motor.

Also, given that I have a catalytic converter, does anyone know of any exhaust specialists that will keep my cat in if I was to have some extractors made? I have been told V-Force will be able to do this.

Squiz....

type1ute Casual Dubber

49 posts · joined Oct 2004 ·

#276367
it has to do withthe valve seats, the lead used tolubricat them to prevent wear, now you can get harden valve seats to run unleaded

mnsKmobi Wolfsburg Wizard

589 posts · joined Aug 2002 ·

#276416
Do a search on unleaded. This q. has been asked heaps of times.

squizy Thinking about another dub...maybe

4,082 posts · joined Dec 2002 ·

#276448
The question I'm asking is what is the difference - and it appears only the valves seats are harder. Is that all? No compression ratio differences?

I did a search and found this thread http://www.aussieveedubbers.com/forum/viewthread.php?tid=2909
which covers the debate unleaded v leaded, but doesn't technically really cover the motor differences.

Re the exhaust setup then - it appears that a lot of people on the forum might be running unleaded in their motors then without a catalytic converter? So theoretically, I could just go and get an after market exhaust and not worry about putting a cat on?

Squiz....

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 ·

#276462
Sqiz

I think you will find the cat is more to do with exhaust emissions.

Yes - you could do a standard exhaust. It would fail emissions for that year though if it was tested. This is more a Cali thing. Never really heard of it being done here.
What year is yours?? 1978? later??

"IF" you were to modify yours and need an engineers certificate you "may" need it again

The difference between leaded / un leaded is the seats. Unleaded ones are harder.
ALL post 1967 VW's had these heads
Yes - some people lower the compression, but that is more to do with the lower octane of unleaded than unleaded itself
Futue te ipsum!!!

squizy Thinking about another dub...maybe

4,082 posts · joined Dec 2002 ·

#276726
Thanks for the reply Barry. Mines a '76. So if I do replace the exhaust, I could just keep my old exhaust anyway and put it back on if I get hassled. I haven't seen the RTA do any emission test lately [touch wood] so I'll add this to my list of things to do.

Cheers,

Squiz.....

Che Castro ankle straps

1,945 posts · joined Aug 2002 ·

#276907
All VW heads have always have had hard steel seats as the heads are alloy. Unleaded isnt a problem and you dont need to modify anything to run unleaded IMO.

Running unleaded fuel on an old car is more a problem when the car has a soft cast iron head with soft cast iron valve seats.

[Edited on 8-12-2004 by Che Castro]
Jon

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#276912
as I said previously in another posting... VW Engines have had Hardened Valve seats and guides otherwise the engine wouldn't last a week as the very soft Aluminium/Magnesium alloy would be worn away....

I believe it could be the Valves themselves...
I have seen Stainless steel Valves for sale...
Maybe these are needed for Unleaded fuel...
If You have a higher than normal compression ratio then Premium unleaded - should be used... plus anything else that will lower the high head temperatures...
and Valvemaster etc just for added protection...
it can't hurt....

I haven't seen this question asked before..... and I don't mind answering the same questions over & over ..
[but only if I know the answer etc]

Lee Noonan -- 20C Heavy Rain - 12.20am SCONE NSW
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#276915
I forgot about the Catalytic converter...
I don't know of anyone still using them on Beetles...
Most have been replaced by a standard replacement Muffler or Extractors..

The charcoal canister is usually thrown away etc...
although if You want to keep using yours, pull it apart and buy some charcoal from a pet supply as its used for filtering water for tropical fish etc... and replace the old stuff....

I don't believe anyone will be checking old cars exhausts IMHO..

Lee --

http://community.webshots.com/user/vw68autobug

1 attachment · Log in to view

- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

carisma Officially Full-On Dubber

263 posts · joined Sep 2004 ·

#276974
i have a cat converter on my 72 bug, and run premium in it and has this weird exhaust twin pipes that join to one and stick out the back so when you walk around the back of car you burn leg if not careful

barls Administrator Causer of Chaos and Mayhem

9,473 posts · joined Jun 2004 ·

#277839
squizy wrote:Thanks for the reply Barry. Mines a '76. So if I do replace the exhaust, I could just keep my old exhaust anyway and put it back on if I get hassled. I haven't seen the RTA do any emission test lately [touch wood] so I'll add this to my list of things to do.

Cheers,

Squiz.....
its in the cards for emissions testing in the rego inspection in the next couple of year i found this out from my old man who is an auvis station inspector
“We all pay for life with death, so everything in between should be free.” Bill Hicks
the chaos project - click me

squizy Thinking about another dub...maybe

4,082 posts · joined Dec 2002 ·

#277998
That'd be our luck Barls. I think I'll definitely keep the cat converter locked up safe and out of the rain for when I need to reattach it. Thanks for the tip.

However how will that set everyone else up who is running unleaded without a cat? Will every possibly be up for an emmissions violation?

Squiz....

barls Administrator Causer of Chaos and Mayhem

9,473 posts · joined Jun 2004 ·

#281992
im willing to risk it for the moment as i know mine is running well with in the specs
“We all pay for life with death, so everything in between should be free.” Bill Hicks
the chaos project - click me

carisma Officially Full-On Dubber

263 posts · joined Sep 2004 ·

#285501
cat=catalistic....think thats how its spelt

Menangler Custom Title Time!

1,991 posts · joined Aug 2002 ·

#285519
I think people are getting mixed up between the charcoal canister (fitted to post '72 beetles in Australia) and Catalytic converters, these were never fitted to any Beetles in Australia, they are only fitted to some late model US imports

The charcoal canister has nothing to do with exhaust emissions, it filters fuel tank vapours only.
FAHRVERGNUGEN;
Description of a pleasurable sensation,
Experienced when a car and it's driver are in mutual harmony, A unique driving experience, Pleasure, Satisfaction,
A feeling experienced by Volkswagen Drivers.

shiftyvw Wolfsburg Wizard

523 posts · joined Sep 2002 ·

#285726
An original VW head should have hardened valve seats suitable for unleaded but when heads got reconditioned back in the day it was unlikly that hardened valve seats got put back it. If you do run unleaded on an old set of heads check the valve lash frequently as a receding valve seat will close up your adjustment.