Itinerant Air-Cooled

4 psi within specification for idle pressure? That surprises me, but it worries me more. As this engine wears in, won't it just be getting worse? I know there are a bunch of variables at play here, but this engine was running significantly lower pressure than even my old worn out engine at any given speed. I fear the "hockey stick ramp" of diminishing oil pressure might come sooner than expected.

Brian's long block was completed in April. Broken in in July and been driven hard in his bug since then. It has a leak around the spin-on oil pump/filter mount, but no other build issues have surfaced yet.

That's good to hear about Brian's long block rebuild. Do you feel that problems are related to the type 4 work? Right now, my 2L bus engine is running quite well; only has a very light oil drip. When Colin comes down in late October, we're gonna be taking a close look at it, and have the guru wheel it around a bit.

Ian, what kind of oil pump do you have on your HFM engine now, and do you run a pressure gauge?

I have wild speculation running around in my head, but nothing that I can attest to in a technical forum. So far, there seems to be a correlation between stuffing a 30/36mm Type 1 pump in there and leaks/low pressure engines. Of course, this is just a thought at this point still, as I've only seen a few like this. I'm off to drive the same route today and compare my oil pressure at identical RPM as last week's test.

Robbie

asiab3 wrote:Ian, what kind of oil pump do you have on your HFM engine now, and do you run a pressure gauge?

I have wild speculation running around in my head, but nothing that I can attest to in a technical forum. So far, there seems to be a correlation between stuffing a 30/36mm Type 1 pump in there and leaks/low pressure engines. Of course, this is just a thought at this point still, as I've only seen a few like this. I'm off to drive the same route today and compare my oil pressure at identical RPM as last week's test.

Robbie

Robbie, oil pressure is only in the service of maintaining an oil film within the journal/bearing clearances. At idle, Volkswagens have enormous real estate devoted to bearing surface area where it is easy to maintain an oil film. VW engineers knew full-well that their air-cooled engines would live with low oil pressure when at hot idle. It is in the owner's manuals. This was obvious to them when designing a sandwich of aluminum and cast iron held together with studs cooled only by air. In the early years, they designed the gallery diameters to limit damaging velocity at high speed and generous bearing surface area to handle the loss of pressure that everyone knew was coming as the engines aged. A VW engine is designed to idle happily at 2 psi. Therefore, the oil pressure switches have a generous spread of acceptable triggering pressure, 2-6 psi. This, of course, is laughable at high speed, where VW engines that throw an oil warning light have mostly congratulated you on your impending rebuild.

Two developments occurred that tried to bring these oiling issues under control.

First was the introduction of the "oil control" valve at the far end of the main gallery. Smart move. It allowed VW to design the entire lubrication system to a much higher flow capacity *without damaging the bearings* due to excessive velocities. The control valve allowed for yuuuge pumps really tremendous, to safely dump the excess volume when clearances were tight and engines were cold, but the pump could then easily deliver to the aged/ hot opened-up clearances.

Second was too late for all air-cooled engines, but the Vanagons had that lovely two-stage warning lamp that used a higher trigger pressure when the engine was at high rpm. It would be a nice thing to have an additional oil pressure switch that triggers at 18 psi, let's say, but is only activated above 2,500 rpm. Then we could save our engines if a problem developed out on the highway at speed.
Colin

who is the cam grinder in question?

the miz wrote:...He told me he thought there was a bigger problem here and that it had to do with the cam .
He said that he had been re building VW engines for over 20 years and he had always had success with his cam supplier until just recently...there had been 5 engines (or so) that he had sent out in roughly the last year that had problems...all related to the cam. He said he suspected this was the same issue my engine was suffering from.
"I'm not buying any cams form that guy anymore" he told me."You have a recipe for success and you stick with it" he added, "...until one of your ingredients is no good and it ruins the whole thing". He noted that he had a few very disappointed customers because of this problem and that it was damaging his reputation. I commiserated, briefly.
He mentioned that he had a new cam supplier he'd been working with (in Stockton...or someplace "up north") and that these cams had been working quite well. "They're a lot closer to stock cams" he said.
I mentioned that I had heard of this possible problem...and gave a brief, anecdotal and anonymous synopsis of what I understood to be the THall story. He said..."oh yeah" ..."that was about a year ago...here's that guy's cam". He picked up the cam in question and pointed out a visible flaw in one of the lobes that could only have come from machining, in his opinion. He mentioned that he had put one of these "new" cams in "that guy's" engine...and that he seemed to be happy. He looked down at the old cam and added something to the effect of "these ones are not made well any more" and then proceeded to show me another defective cam from the same source.
"I've got 5 cams on the way from the new source", he told me, "...one of them is yours; I'll get it put in and have your engine sent back to you before the end of April". He continued: "this kind of stuff is inconvenient for you and it's inconvenient and expensive for me...I know you don't want to pull your engine and ship it...you want to be driving your van!"
So we left it at him "making this right" for me...and chalking the incident up to a bad cam and an unfortunate experience altogether. He was very, genuinely, apologetic.
I hope he gets the problem sorted out quickly with this new, non-performance cam...and my engine will run well...

I did a search on TheSamba under "cam and THall." All I can find is a thread there I remember where Adrian put a racing camshaft into a bus engine which left it loping at idle and no vacuum at idle so it fell flat on its face. That is simply an engine builder not understanding what he/she is building an engine for - or perhaps an owner saying something like I want the most horse power I can get. Yes that engine would have put out lots more power than the stock cam but unless someone wants to drive around at 4,000+ RPM 100% of the time the power can't be accessed.

If someone knows of any other threads where it was a cam blank problem please post it here. Schneider was the cam grinder. Putting the wrong camshaft in a car is not the grinder's fault unless they recommended it for that application - and in fact they do not and never have. I spent considerable time researching this one when it happened.

sgkent wrote:

the miz wrote:...He told me he thought there was a bigger problem here and that it had to do with the cam .
He said that he had been re building VW engines for over 20 years and he had always had success with his cam supplier until just recently...there had been 5 engines (or so) that he had sent out in roughly the last year that had problems...all related to the cam. He said he suspected this was the same issue my engine was suffering from.
"I'm not buying any cams form that guy anymore" he told me."You have a recipe for success and you stick with it" he added, "...until one of your ingredients is no good and it ruins the whole thing". He noted that he had a few very disappointed customers because of this problem and that it was damaging his reputation. I commiserated, briefly.
He mentioned that he had a new cam supplier he'd been working with (in Stockton...or someplace "up north") and that these cams had been working quite well. "They're a lot closer to stock cams" he said.
I mentioned that I had heard of this possible problem...and gave a brief, anecdotal and anonymous synopsis of what I understood to be the THall story. He said..."oh yeah" ..."that was about a year ago...here's that guy's cam". He picked up the cam in question and pointed out a visible flaw in one of the lobes that could only have come from machining, in his opinion. He mentioned that he had put one of these "new" cams in "that guy's" engine...and that he seemed to be happy. He looked down at the old cam and added something to the effect of "these ones are not made well any more" and then proceeded to show me another defective cam from the same source.
"I've got 5 cams on the way from the new source", he told me, "...one of them is yours; I'll get it put in and have your engine sent back to you before the end of April". He continued: "this kind of stuff is inconvenient for you and it's inconvenient and expensive for me...I know you don't want to pull your engine and ship it...you want to be driving your van!"
So we left it at him "making this right" for me...and chalking the incident up to a bad cam and an unfortunate experience altogether. He was very, genuinely, apologetic.
I hope he gets the problem sorted out quickly with this new, non-performance cam...and my engine will run well...

I did a search on TheSamba under "cam and THall." All I can find is a thread there I remember where Adrian put a racing camshaft into a bus engine which left it loping at idle and no vacuum at idle so it fell flat on its face. That is simply an engine builder not understanding what he/she is building an engine for - or perhaps an owner saying something like I want the most horse power I can get. Yes that engine would have put out lots more power than the stock cam but unless someone wants to drive around at 4,000+ RPM 100% of the time the power can't be accessed.

If someone knows of any other threads where it was a cam blank problem please post it here. Schneider was the cam grinder. Putting the wrong camshaft in a car is not the grinder's fault unless they recommended it for that application - and in fact they do not and never have. I spent considerable time researching this one when it happened.

So, how does the neophyte owner stand fast against an engine guy who says, "we recommend this (X) cam, helps it run cooler and gives you better freeway performance, you'll like it, I put it in all my engines, etc . . . "

I have listened to this patter myself. When I ask a pointed, focused question like, "What will that camshaft do to idle airflow on my L-Jetronic engine?" they breeze RIGHT OVER ME, "oh, yeah, no, not a problem."

I just today idled up a dirt path in 1st gear with a 4,150 lb Westfalia and the engine pulled smoothly at 1,300 rpm and a 14.9:1 a/f.
I could not do that with a performance cam, I would have had to slip the hell out of the clutch.
Colin

Appears that some engine builders have taken lessons on answering questions from our politicians.

Amskeptic wrote:

sgkent wrote:

the miz wrote:...

I just today idled up a dirt path in 1st gear with a 4,150 lb Westfalia and the engine pulled smoothly at 1,300 rpm and a 14.9:1 a/f.
I could not do that with a performance cam, I would have had to slip the hell out of the clutch.
Colin

I don't have that problem with a 9550 Raby cam so what cam or cams are you talking about?

Bleyseng wrote:I don't have that problem with a 9550 Raby cam so what cam or cams are you talking about?

Just looking at cam numbers, I can't tell what will or will not work. But there are people here who have suffered because of them. Ask RustySub about his lackluster idle on the performance cam 2.0L he's running. (His engine sure works well above 5,000 rpm!) Or about THall and his engine that was sent back for a cam swap. One time I accidentally left my bus in third at a stop sign and let the clutch out slowly. One or two shudders from the crank and it just took off and went. That kind of safety net doesn't come with dropped vacuum and airflow at idle.

Robbie

There are two questions here. One is what cam will work, and the other is who can one trust to build a T4 motor. The answers are simple. To answer what will work do some research before deciding, Drive a bus with the desired cam and see how it runs. I chose the Webcam 142. It is from the stock T4 2.0 95 hp GA 914 motor. It is quite acceptable both as to grind, performance and workmanship. The GD and GE bus motors have 70 hp so the GA motor is a leg up at 95 hp. The second question unfortunately has a bad answer. Probably no one if the standard is a motor that runs well and lasts. The cost would be about $12K for a T4 motor to have it done right turnkey. I base that on $5500 in parts (new heads etc) and $6500 labor. No one will pay that. AND the answers are a moving target. At what point does a name brand change where the parts are actually made? At what point does a well known machinist sell or retire? When does the engine builder retire? Without factory support this answer changes from time to time. I would not want the job - listening to people whine about "when will it be done, can't you cut a couple dollars out of it, I've decided to sell the bus and don't want the engine anymore, I found a $200 block I am going to try to do myself..... " AND, that is with no warranty - I'd add $1500 to the cost if I am to warranty it. That covers shipping costs and the yokels who broke something putting it in.

My point is "if" you say a blanket statement like performance cams don't work please name the cam so people don't buy it for a stockish rebuild. Yes, the Webcam 142 (solid lifters) which is the stock 914 Djet grind is fine in a type 4 bus with slightly better rpm range with plenty of vacuum at idle.

performance cam in my vanagon that just will not idle right, no matter how warm it is. builder swears up and down these engines will run right with this setup but i have been through 6 mechanics now and even the one the builder likes is now telling me "you may never get what you want." i want an engine that will idle and won't die when i go to accelerate. impossible?

What makes a cam "performance"? The angle of the lobes? The length of the lobes? Is there a way to trick the cam with timing adjustments?

I know nothing...woefully...

cegammel wrote:What makes a cam "performance"? The angle of the lobes? The length of the lobes? Is there a way to trick the cam with timing adjustments?

I know nothing...woefully...

You push a child or your girlfriend on a swing. The movement is called an oscillation. It goes first to one side then the other then back again over and over. The rhythm is determined by swing rope length and weight. The same kind of thing happens to the intake charge coming into an engine, and the exhaust in the pipe leaving the engine. It also happens inside the cylinder. The camshaft has a base lobe. That is a circle around the base. Any area above that is the lobe. The lobe can be tall, short, long or peaky. That lobe determines how fast and how long the valve is open. Timing when the valve opens is like you pushing your friend on the swing. If the intake valve opens too soon the pulse in the intake runner is headed the wrong way. Same kind of thing on the exhaust side. And in the cylinder the piston is trying to move air in and exhaust out in time with the piston going up and down. If the valve is not open long enough the process is hampered. If the valves are open too long or both open at the same time they may fight each other. As the engine RPM increases the air column, which has mass, requires a different timing in order to let it in - sort of like a hunter shooting at a fast flying duck vs shooting at one moving slowly. As the RPM and air speed increase, the valve has to lead a little and overlap with the other valve. At low RPM that arrangement won't work. Late cars like Honda's VTEC have multiple lobe cams that adjust with the speed of the engine. Our engines have 1 cam. We have to choose what works well with the engine use. What is happening in this community is that people are generally disappointed with the power their buses have. They are comparing them to late SUV's which have hundreds of horsepower and lots of torque. People want something other than a stock cam so they ask for more and the engine builders, who don't have a lot of experience with heavy slow moving buses are using cams for lighter sportier cars that use the same engine. In general the number of degree a cam is and the timing tells one how it will perform. The reliability of the cam builder tells one how it will last.

The degrees of a cam are given usually 2 ways. One is how long the valve is open in degrees, and the other how long it is open in degrees once it is .050" of lift. The idea being like - the .050" number is how long it is effective. At idle .050" of lift would kill an engine. I use total degrees because that is all which was given when I was racing and that is how data is stored in my mind. There is no standard in the industry for how a certain number of degrees performs due to variances in engine design. That said here is something to consider:

220 - 240 general stock street applications
250 - 270 mildly improved street design, more HP, equal torque, less efficiency but for a more aggressive driver
280 - 300 street racing around. Someone who pushes their street car all the time. Will never pass smog because it will lope badly.
310 - 320 full race track only.