TheSamba.com :: View topic

Tue Apr 06, 2010 8:07 am

Hi all, I have an '89 Vanagon with stock engine. I recently found a pretty good deal on another '88 Vanagon in a little better shape so I'm going to "upgrade."

One thing I noticed driving the '88 home is it seemed to have less power, even though a rebuilt engine was installed 5-6 years ago (seems to have had low miles since then).

The biggest difference is that my '89 has the A/C compressor removed (previous owner said for "more power").

Has anyone else seen a noticeable power difference with and without A/C? I wasn't running the A/C... it should have just been turning the pulley, unless I have pulley clutch problems I suppose.

There was also a noticeable whine from the back-end... I need to check the diff/trans oil ASAP (manual transmission). But I do not suspect this for the lower performance.

Thanks!

Tue Apr 06, 2010 8:12 am

Different tire sizes can make it feel like a performance difference. Larger tires make it feel slower.

Tue Apr 06, 2010 8:46 am

Is it not true that A/C can decrease the power in any four cylinder. ? There is a noticeable downgrade when it kicks in. At least I've always found it so. I've owned all 4 cylinder standard vehicles. I gave up on constant repair of A/C as its like fighting yourself! They say that running an A/C is like driving with a window wide open at highway speed.

My 84 Westy has its compressor out for the same reason as mentionned above and was done by the previous owner.

Tue Apr 06, 2010 8:59 am

Tires are 205-70r14 on the new van. Same as on my other van I believe, definitely both 14".

If the a/c only hits performance when running, why remove the compressor? Weight?

I'm in southern California so definitely want to keep the a/c with summer coming up!

Tue Apr 06, 2010 9:07 am

The tires on the other van might be stock 185 / 14's. That might make a noticible difference.

Also if the AC clutch isn't working, you will have a draw from the compressor.

Tue Apr 06, 2010 9:31 am

Hmm I'll have to compare tire widths and check out the A/C clutch... thanks for the info!

Tue Apr 06, 2010 10:10 am

Here in the Great White North (and remember Cda is a lateral country east to west) I don't think as many people feel that the A/C is an absolutely necessary thing but having said this I know that a lot of car vehicles are addicted to their A/C. We get some hot and some really muggy weather but we are fortunate not to get like the south and south west/east of the States get. I don't mind heat as long as its dry!!!

Guess you all have a different head space than most of us. Don't get me wrong, I have a dehumidier and A/C at home for those muggy muggy times. A gals gotta sleep after all.

On my 4000 mile trip last Nov I really liked the wee wing windows. They are great and I'd be more upset not to have them than not having a functional A/C. I will wait for the winter to head to Az, NM, etc....

Tue Apr 06, 2010 10:35 am

carlivar wrote: it seemed to have less power, even though a rebuilt engine was installed 5-6 years ago

I would be suspicious of the rebuild. They're not all the same. Your slow engine might have been rebuilt with low-compression brazilian or chinese pistons.

Tue Apr 06, 2010 10:38 am

I've got a receipt with the van showing 130 compression in all cylinders. But that was from several years ago -- so good idea, I'll do my own compression test.

Tue Apr 06, 2010 10:41 am

I've only once in my life seen an AC clutch stuck closed (in a brand-new Ford Exploder, go figure; it roasted the compressor), so it's rare but it can happen. Funny thing was how my friend noticed she had a problem: when she switched on the defroster there would be a terrible squealing and the engine would die. Since about the mid-80's most cars with AC use it to dry the air for the defroster.

Just look at the compressor hub with the engine running, the hub should only be seen turning if the AC is switched on, it will engage and disengage intermittently then. Otherwise there is no significant power loss from just running the belt over the idling pulley.

Quote: They say that running an A/C is like driving with a window wide open at highway speed.

Well people like to generalise, it's in our nature, but there could be no rule of thumb for that kind of choice because every car design has different aerodynamics that also vary greatly with speed, and adding something like a roof rack or even as small as a bullibar or changing the side mirrors can affect overall drag coefficient (Cd) dramatically and in unexpected ways, as can opening a window. But we can know how much power the compressor consumes, and it's generally around 6-8 hp, when it is engaged, which is only part of the time. The duty cycle varies directly with how cold you want it inside vs. how hot it is outside, obviously. In newer more aerodynamic passenger cars the increased aerodynamic drag of having one or more windows open at highway speeds is easily more than the overall power use of running the compressor, don't forget that you have to use the duty cycle to compare, not the actual compressor load because it's only a load a part of the time. With a barn-on-wheels like a Vanagon, it's probably a moot point, opening windows won't have as large an effect on Cd as a more streamlined body would. But swinging the vent wings out for old-school "VW AC" I could practically promise you would cost you more in fuel usage than running the AC system at a reasonable level, and at a certain point the air those vent-wings direct at your face is too warm to provide comfort anyway.

I don't find an AC system to be any real trouble to keep working at all, if the system is tight it generally doesn't need any attention for ten years at a stretch, or even more. There are loads and loads of 20-year-old vehicles on the roads with the factory R12 refrigerant charge still in the pipes, all that has ever needed changing is the compressor belt. But then most of the complaints poeple have about so-called "complicated systems" say more about their or their mechanic's general ineptitude than the they do about the complexity of the systems; an AC system is not very complex and is pretty much the same from one car and even one make to another. I can walk up to any AC system regardless of manufacturer and service it, with little to no change in my procedures. Most things in cars are actually this way, people develop a favored "mystique" around their favored vehicles, but 85% of how any car works it has in common with most of the other cars of its era.

But as to the OP's doggy new van, the announcement that the engine was rebuilt makes me think it might have the low-compression Cofap pistons in it that have been popular with budget rebuilders for many years now. They can be put in a 2.1 engine and make it less powerful than a factory 1.9, and it gets poor mileage to boot. There are ways to determine if this is so, a compression test can indicate that (it will only be in the 110-130 psi ange, not 150-170 like you typically see on original 2.1's). There are also ways to directly get a deck clearance measurement but they are beyond the scope of a forum like this.

<late edit> While I was writing you guys already touched on the piston issue and by the numbers I would say that's what you bought. Carry on...

Tue Apr 06, 2010 11:14 am

I've had nothing but problems with A/C hoses. I've never gotten more that 1 maybe 2 seasons and then they leak. Our Ontario laws are that the whole system must be tested and reset. I believe that I have had all the rotten luck with A/C's so have given up BUT you should see cranky me when the relative humidity is way up. I'm a grrrrr :evil:

Tue Apr 06, 2010 12:06 pm

tencentlife wrote: makes me think it might have the low-compression Cofap pistons in it that have been popular with budget rebuilders for many years now. They can be put in a 2.1 engine and make it less powerful than a factory 1.9, and it gets poor mileage to boot.

Ugh. This sounds like the most likely explanation. Didn't know about this piston problem. It certainly explains why my '89 with high mileage stock engine feels more powerful. Well, thanks for the explanation... now to choose which Vanagon to keep...

Tue Apr 06, 2010 6:00 pm

Unfortunately it's a common problem. I think that lots of vanagon owners who complain about the underpowered waterboxer may be driving low-compression dogs. I've bought three vanagons and two of them had the wrong pistons in the engine. The commonly used aftermarket pistons for rebuilds have a lower deck height and/or wrong dish in the piston, resulting in insufficient compression in the combustion chamber. Tencent and I have written about it on the samba, he at greater length and with more clarity if you care to search for some of his posts. And there's this Gowesty article with pictures, to give you a visual:

http://www.gowesty.com/library_article.php?id=105

I bought my van with leaking headgaskets, discovered that it would only go up hills veeeery slowly, and when I pulled the heads for a reseal I found the pistons at TDC were still well shy of the top of the cylinder. I splurged and bought the Gowesty 2.2 pistons and installed them along with new headgaskets. Well worth the money if your engine is otherwise sound.

Tencent also builds a nice, higher compression WBX and does an excellent job by all accounts. Rocky Jennings can put together a nice custom kit for rods and pistons, and has the know-how to build an engine (although I don't know if he's advertising such a service). And Gowesty builds good engines, too.

Tue Apr 06, 2010 7:35 pm

Yes, Rocky builds wbx's too.

Tue Apr 06, 2010 10:54 pm

<<Also if the AC clutch isn't working, you will have a draw from the compressor.>>

No Sir.
If the AC clutch isn't working there is no drag at all on the engine.
So--in essence , and in reality, removing the belt or the compressor is a total waste of time and of no benifit to get more motovation out all of your 90 horses.

The only time the boat anchor kicks in is when the clutch is operational, and the compressor is working.

Tue Apr 06, 2010 10:57 pm

<<I've had nothing but problems with A/C hoses. I've never gotten more that 1 maybe 2 seasons and then they leak. >>

By simply replacing the 20-30 year old hoses & fitting O-rings , you just might get more than 2 seasons out of an AC recharge.

Wed Apr 07, 2010 12:10 am

guess I didn't make myself clear. All hoses replaced on my cars every two years approx and have to go thru test and refill. About a $600 plus bill. Our winters are harsh on A/C systems in old cars. We only need air for a very short time altho with climate change that seems to be increasing. No I don't have A/C in my Westy. Its there but no compressor and no intent to replace.