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
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 ·
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.
Secoh ·
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.
Kombi Dad ·
I find it strange then that Stan Pobjoy still recommends Flashlube in the 1380 that he built for my '63 single cab.
Bizarre ·
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
rozrob ·
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 ·
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 ·
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 ...
helbus ·
We have run our Beetle on 91 unleaded for two years with no additive and no change in motor running
The Bus was run for about 5 years on Optimax and no additive with no problems.
And well duh we just run it on 95 unleaded with the Suby motor now, but I know that;s different.
cab1303 ·
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 ·
cab1303 wrote:Does anyone else use unleaded 95 over optimax.
yep :thumb
PrettyBlueBug ·
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 ·
been running it on premium for the last 10,000 miles on a rebuilt engine. no problems with valves.
helbus ·
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.
PrettyBlueBug ·
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