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unleaded quiery

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rozrob Slammed & Awesome Dubber

85 posts · joined Jan 2003 ·

#425702
ok this has probably been asked before but i'll ask anyway. what do i have to do to get my kombi running on unleaded fuel without adding the additive? is it a matter of getting hardened valve seats put into the heads? the reason i ask is because it looks like i'll have to get my heads rebuilt in the near future would like to get it converted to unleaded if it aint to exey.:beer

PrettyBlueBug Almost over it...

2,032 posts · joined May 2005 ·

#425715
I took my Beetle to my mechanic on Friday last week because she's been running a bit ragged on idle and lacking a bit of power.... and I was told to stop putting the additive into my fuel tank! They don't need it. I filled up this morning without it, so will see how she goes! Apparently it can build up with a gel-like substance and cause probs in the carby, fuel filter, etc.

Purple Martin Fahrvergnugen

913 posts · joined Feb 2003 ·

#425882
vw heads don't need the seats hardened, they are already hard! Therefore they can run on unleaded without any additive.

I've heard that the additive makes the heads run a bit cooler, which seems to me to be a good thing in an air-cooled motor with a reputation for valve troubles.
1959 red & white Beetle
1975 Kombi camper

Secoh Fahrvergnugen

926 posts · joined Sep 2002 ·

#426138
if it pings then use premium and retune it to that. That's all you have to worry about with unleaded and air cooled VW's.
If it aint broke,
Make it go faster!!

Kombi Dad Slammed & Awesome Dubber

96 posts · joined Jun 2003 ·

#426507
I find it strange then that Stan Pobjoy still recommends Flashlube in the 1380 that he built for my '63 single cab.

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#426528
Different people have different opinions

Personally i just use 95 Octane

Have been for a long time.

Others swear by Flashlube.
I think this is slightly different from Lead Replacement Petrol. (LRP). Flashlube is a upper head lubricant as opposed to thehard/spft valve seats.
I think it is unanimous the LRP is crap.

If you feel better using Flashlube then use it
Futue te ipsum!!!

rozrob Slammed & Awesome Dubber

85 posts · joined Jan 2003 ·

#428385
well i think i'll just keep using that additive, might fork out that extra couple of cents for premium. I have tried a few different aproaches,travelled most of the way round australia without any additives at all on unleaded with no short term effects. and a little while back even tried using 2 stroke oil. the only reason i am a little concerned now is i got her compression tested the other day and the engine is not in great shape. it goes like this cylinder 1) 100% 2)70% 3)75% 4)70%. so can't help thinking something caused ecesive wear on the engine.
Then again could be all the km's we've done in hot conditions. or a bit of neglect on my part.

tom_1973 Learner Dubber

3 posts · joined Nov 2005 ·

#429265
rozrob wrote:ok this has probably been asked before but i'll ask anyway. what do i have to do to get my kombi running on unleaded fuel without adding the additive? is it a matter of getting hardened valve seats put into the heads? the reason i ask is because it looks like i'll have to get my heads rebuilt in the near future would like to get it converted to unleaded if it aint to exey.:beer
Apparently there are "stellite" valves available these days which are more appropriate (harder) for unleaded fuel but I've accumulated a variety of opinions on the issue - including the Muir section and the consensus seems to be that the valves themselves don't need to be any harder.

The key issue is the octane level. The octane level of the old 'super' or leaded fuel was high - 90+. High octane leves prevent pre-ignition in the cylinders. Pre-ignition causes a pinging sound and is harmful to the engine. Lead was used partly to increase the octane level and partly to lubricate valve seats.

If VW valves are hard enough to not worry about the lubrication bit, then we simply need to deal with octane levels: ie. use premium unleaded which has a much higher octane level. This can also be solved by changing the compression of your engine - ideally done at the same time as your valve job. If the compression is lowered then you can use regular unleaded. This basically involves adjusting the length the pistons travel within the cylinders.

Personally, I'm interested in raising the compression, and staying with premium u/l for more power and a cleaner burn ... but it's a question of economy too.

tom_1973 Learner Dubber

3 posts · joined Nov 2005 ·

#429266
rozrob wrote:it looks like i'll have to get my heads rebuilt in the near future would like to get it converted to unleaded if it aint to exey.:beer
btw - i got a couple of quotes on having the compression changed and it varied from $500 for a straight compression change (good mechanic) to about $1500 for a conversion to stellite valves and compression change (from someone who has since turned out to be really dodgy).

nonetheless, if that's what you decide to do then there are the figures i have. Personally, I'd just use premium and keep searching for an answer about whether flashlube really does help or not. Muir believes that it only creates more pollution ...

cab1303 Seriously Crusin Dubber

104 posts · joined Apr 2005 ·

#429512
I have been running unleaded 95 since it came out but before then i was using optimax, and i have had no problems also adding an additive every 3rd or 4th fill. Does anyone else use unleaded 95 over optimax.

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#429538
cab1303 wrote:Does anyone else use unleaded 95 over optimax.

yep :thumb
Futue te ipsum!!!

PrettyBlueBug Almost over it...

2,032 posts · joined May 2005 ·

#429551
I mostly use Unleaded 95 in my Bug... was using Optimax, though every now and then I'll use it. I don't use any additives now. 😀

Che Castro ankle straps

1,945 posts · joined Aug 2002 ·

#429565
been running it on premium for the last 10,000 miles on a rebuilt engine. no problems with valves.
Jon

PrettyBlueBug Almost over it...

2,032 posts · joined May 2005 ·

#429652
Helbus wrote:
cab1303 wrote:Does anyone else use unleaded 95 over optimax.
We only use 95 in all our cars and bikes, except the KOC Beetle which is a little slut and only deserves 91 because it only runs on 3 1/2 cylinders.
Hahahaha poor thing.... :P
My 2nd car was a 1983 Ford Laser.... for a few months it was running on 1.5 cylinders, no idea how. :P