2000 L problems

doug77 · Post by **doug77** » Sat Jun 09, 2007 2:56 am

Hi guys

Camperman are the cutoffs you mention the one in this pic ?

labelled as "idle circuit cutoff" and "Pilot cutoff" the whole article (excellent) on adjusting 34 PDSIT 2/3 carbs by Richard Atwell can be found here

Most articles on adjusting carbs without pictures just make me dizzy.

I haven't the guts to pull my carbs off ... it's not running too bad .. but it's not right.

The other comment was to do with replacement carb and i can't remember where i got the hint from but it went along the lines of one night on the net - got tip about single pierburg carb and the next day there was one for sale in the junkmail (with manifold and air filter holder)-it stood out like a saw thumb. so i grabbed it (not the thumb) for R150 (plus travelling to Queensburgh) If you want I can get the info from it lying in the garage. It's lying there in case of emergency type of thing.

camperman · Post by **camperman** » Mon Jun 11, 2007 8:21 am

That is the ones that gave me some pain. My idle cutoff valve (fattest one) is disabled at the moment, cant get a replacement. I also had problems with the rubber elbows and replaced them with spark plug wire boots. Works great. That is the ones that goes onto the base of the inlet manifold, I think they help with equalization or something. Ratwells site is the best place to get info on these busses.

Post by **IMPI** » Mon Jun 11, 2007 8:37 pm

once valve clearance goes away it means that valve is stretching
replace all the exhaust valves.
Armand

doug77 · Post by **doug77** » Mon Jun 11, 2007 9:21 pm

Can u guys confirm the following?

The guy that sorted my valves out said that the motor (1800) same as campermans', had self adjusting tappets .. or something like that. I notice sometimes when i start up in the morning it's a little noisy then goes away quickly not like piston slap .. my pistons are good.

The other thing that's been puzzling me is regarding exhaust. It's not so much that the two lengths must be equal but more the correct size of the box? I.e I was told that if the box is not right size then back pressure will be to little and THIS will also shorten the lifespan of the exhaust valves.

The second issue is bugging me now beacause my valves were replaced not so long ago and i see from your comments impi that it was pretty much spot on with the mileage you suggested. (75 000km) and i want everything to be correct.

The other exhaust issue was stainless vs mild steel.

I'm alsmost inclined to pull the stainless off and put mild steel just for temp reasons but if some one can convince me not to, BIG THANKS in advance for saving me some bucks.

Post by **Tony Z** » Tue Jun 12, 2007 12:47 am

The exh valves are known to start failing at around the 75K miliage (I thought it was more like 60k to be honest)

there were numerous VWs (even the humble 1600TP) That had hydraulic tappets. Yes, thats the knocking you hear in the morning waiting for the cam followers to build up pressure and take up the valve clearance.
I have never worked with hydraulic tappets, but I think I may be correct in saying that if they clatter and bang in the mornings, the non-return vlave in them is leaking and the next time you have your heads off, you should pull out the tappets and have them reconditioned.

I am not so sure of the exhaust comment - lack of pressure. I actually dont know which way to look at that comment. two ideas
1) if you dont run an exhaust, you have zero backpressure, but you do end up burning valves. Then again, you also have nothing to remove the heat from the head - the exhaust does act as a good heat remover from the head allowing a lot of the heat to get soaked into the metal itself and get drawn away from the head
2) too little back pressure in my eyes would mean that the exhaust would flow away from the head more quickly. Meaning cooler valves. If the exh gas would get stuck around the valve (high back pressure), it would heat the valve from the back and the chamber would heat it from the front. Not good. Maybe the thought of overheating your valves comes from the possiblity of having slightly more power due to better breathing ability of the chamber in a whole and thus higher combustion chamber temps as well as higher exhaust gas temps, thus the vlaves do run at a higher mean (average) temp which they were not designed to do and thus fail.

I feel like a lecturer here, its 0045, midnight shift and I am slowly waking up....

As for the Stailess steel... well, stainless is known to be a bad conductor of heat (metalically speaking), so it doesnt like recieving heat, so yes, it doesnt cool the head as well as mild steel will. But it does last longer.
This actaully brings up a question in my mind.... how well does the ceramic coated exhaust work. hmmm, the exh gas doesnt really heat the pipe, so it remains cool. The heat from the head will get into the pipe through conduction.... but then??? Its ceramic coated on the outside too, so it wont shed the heat that well through convection to the atmosphere... hmm, more thought invlolved here... I'll get back to you on that one

camperman · Post by **camperman** » Tue Jun 12, 2007 8:31 am

Regarding the exhaust: I replaced mine myself the beginning of this year with a stock standard bosal exhaust. The previous ones insides rusted away so it made a bit of noise. My feeling is that I definitely want the stock exhaust - I really like the traditional flat four vcw sound from a kombi engine, also these exhaust will last many years as they do get very hot so rust is less than in say a normal car. Obviously this depends on the distances you travel - going only to the corner cafe will create more vapor that will not evaporate as the engine doesnt get that hot. These autovillas were meant for long distances so this should not be a problem. In soeaking to a guru from the beetle club it was suggested that the stock exhaust works better as it was engineered specifically for the komby. That is why it am keeping my stock one. It is expensive +- R900, but easy to install yourselve. I am not sure if you get these standard ones in stainless? The heat exchangers is another issue

I am not sure about the valves, but I was under the impression that only 2 litre engines were made with them

It definitely sounds as if you do have hydraulics. Mine is not so I check clearances EVERY tune up. By the way - it seems that the single carb setup is a nono. Read Ratwells website... http://www.ratwell.com

Here is what he has to say about hydraulic lifters:
"In 1978 VW introduced Hydraulic lifters to the Type IV (GE) engine. Because they were only used for 2 years on the baywindow bus, they attract the usual disdain and confusion that the Type IV engine, fuel injection and other late model parts and features have to endure. Bob Hoover thinks they are a good idea and like the rest of the Type IV improvements, so do I, coupled with the fact they've never let me down.

Over and over you will hear how they were a bad idea and they should be removed from the engine but the fact is that VW produced over two million vehicles (mostly Vanagons) with these lifters and there was never a single recall. That number doesn't even count that number of hydraulic engine equipped beetles running around in Mexico and Brazil.

So who's right? The beetle owner who has never seen one and who insists that they should be removed from every engine or VW? Let's find out."

doug77 · Post by **doug77** » Tue Jun 12, 2007 7:25 pm

The plot thickens.. thanks to all the plot thickeners...

Tony Z - Good luck with the can of worms you've opened there with the ceramic story.

The stainless vs mild steel thing still hinders me.
Buddy had his 1600TP redone and put stainless on - had problems (heat) and swopped back to mild steel. But it's not clear that the problems were exhaust related as there were other snags at the time with the freshly redone motor. But he is for mild steel.

Then camperman ..looks like you are pro mild steel ... but you went from susty mild steel to ..er.. new mild steel. And Tony Z remained neutral i.e.
My feeling is surely keeping the head as cool as possibe would save more money than replacing the exhaust every say 5 years. If the head has to be done evey 5 years anyway then i suppose why worry just stick to stainless. Gut feeling says mild steel.

As everybody knows on a cool day there's much more grunt (well for tortoise anyway) as opposed to a hot day.

Another buddy has little heat sinks (with fins) on his exhaust at the head.
Maybe that's the solution .. well cheapest anyway. So where can i find these heat sinks? Any one in Joburg area sell these? if so please pm me. My sister is coming to visit soon ans she can bring/fetch them.

<edit>

Post by **Tony Z** » Tue Jun 12, 2007 7:36 pm

those heat sinks are the stock beetles heater box, with the cover removed. They limit the exhaust and cause dropped exh valves on anything other than a stock engine....

as for the hydraulic lifters, you can buy stock 1600 cases from mexico which are meant for use with hydraulics.

I have done some research.... and here it is...
the reason for having no exhaust and then dropping valves is actually pretty simple, but not something I thought would happen... It is pretty good for getting the exhaust gas out, but then when the cylinder pressure is lower than atmospheric, the flow is reversed and fresh air enters the chamber. This air adds to the incoming air and thus leans out you mixture and you get extremely high temps from the lean mixture and this kills the valves, piston and causes engine overheating. Apperently the exh itself doesnt do too much in the lines of head cooling.

I personally have run mild steel (lack of money) twice and am fairly happy, except that they rust through. I now have a ceramic coated exh sitting at home and if I had the time and the funds would definitely go stainless - but not for a turbo though

doug77 · Post by **doug77** » Tue Jun 12, 2007 7:58 pm

Aahh Thanks Tony Z

So the comment about the size of the silencer box is correct because that determines the back pressure? Just want with your help to conclude the myth busting on that one. Can we go on to say that the size of the silencer/s is more critical with aircooled? ( Can't let it go can i!)

Post by **Tony Z** » Tue Jun 12, 2007 8:05 pm

the size plays no role in airflow in any way. You can have a 10litre can with a shit design that adds backpressure until you car wants to burst, while at the same time, you can have a properly designed 5 litre can that silences very well and has minimal restriction. You get what you pay for, buy cheap and you get cheap

doug77 · Post by **doug77** » Tue Jun 12, 2007 8:15 pm

Ja u see these tyre guys try and con u. When i replaced my rear tyres (Qui..F..) the guy looked at exhaust and made the comment about the silencers...basically he just wanted to sell me something extra while i was there...

doug77 · Post by **doug77** » Tue Jun 12, 2007 8:28 pm

Tony Z ... if your're still online ..any suggestions on exhaust studs. Two of mine have come out with the 2 nuts.

What is correct length of the studs? (1800/2000 motor)
Are the studs the same on all aircooled?
Any tips? i.e can i buy some threaded bar and cut to length and make my own or are there a few snags to watch out for?

Post by **Tony Z** » Wed Jun 13, 2007 12:53 am

the easy answer here is to use loctite blue or red and surely it will help. You might never get the studs out again with the red....

For me, my exhaust needs a bit of fighting when I put it on or take it off, so a stud that comes out is sometimes a saving grace.

I am not sure if VW every recommended a thread locker compund to keep them in the head. I just use a moly slip on the outside threads (moly holds higher temps than copper) to make dissasembly easier and prevents rusting. Also a good wad on it after the nut is tightened helps prevent corrosion of the rest of the stud at a later stage.

Take the studs into a good nut and bolt centre and see if they have replacements. Its not an uncommon size thats used on the heads. You actually want the bit in the middle that makes it a stud and not a threaded rod, it helps locate the exh better and doesnt get fretted away like threads would.

If you do use thread bar, use a good grade, like 8.8. I suppose a grade 6 is ok, but stay away from grade 4. Grade 10.9 is prob overkill and not that easy to find

doug77 · Post by **doug77** » Wed Jun 13, 2007 4:46 am

thanks for that.

I don'y actually have the studs that have come out.
They are lying on the road somewhere from here to ..?
I have a piece of a stud that sheared from the panel van days so i can match the thread. I just assumed it was threaded all the way... and the length?

Post by **Tony Z** » Wed Jun 13, 2007 10:01 am

no idea about the length. Go to your local volla guy (volkspares if really necessary) and see what they got lying around