Type 4 stock cam specs

[E4ODnut]

I'm looking for the cam specifications for the stock type 4 engine, '76 bus in particular. I'm not having much success. Anyone have this information?

[modok]

The hydro cam is probably about 200degrees at .050"
Go to www.webcamshafts.com, and find the type-4 camshaft listings, click on the grind number to see the cam card

[nextgen]

Interested, what are your plans with the engine are you trying to compare an after market cam.
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[E4ODnut]

Glen,
Thanks for the link. I had found that site before and it is the only reference I've found for the stock grind, solid lifters. It would be nice to get another opinion.

Nextgen,
Actually this is part of my research for an engine my son built for his '76 Westy. The build hasn't worked out as good as hoped so we plan to tear it down this winter and correct whatever is wrong. I have serious reservations about the cam he was recommended to use.

The engine was to be built for torque. The bus is heavy fully loaded and pulls a little cargo trailer as well. Cruising RPM is between 3000 and 3200. It will probably never see over 4200. My gut feeling is that it would probably be hard to beat the stock grind in this application. In any case if I have the stock numbers I can plug all our data into Desktop Dyno then play around with different available grinds and see what it does for the theoretical torque curves.

[modok]

You could just degree the cam and find out yourself. IMO, you don't need to know, just think of the wimpiest cam possible......

The stock engine has a super wimpy hydro cam and very small valves. I don't think dextop dyno will appreciate how bad it really is, in fact people who bought them new won't even admit how bad they were.

With a web 73 and 42x36 valves it will probably make more torque from 2000 RPM up....... I don't know what you need to go bigger on the heads AND cam, but i would do at least one of those things.

[E4ODnut]

Certainly, I could degree a stock cam myself if I had a new one, which I don't. I don't even have access to a used one which doesn't show obvious signs of wear.

What I am trying to do is establish a known baseline to compare to. Without that anything else is just conjecture.

[Alstrup]

The type 4 bus cam is the lousyest cam of them all, period! if you are about to swop cam, take a serius look at what is avbailable and take a look around and see what works and what don´t. I can easily see your son been mislead about cam choice for a bus, - and the entire set up. Too many desk guys think in the wrong directions.

But before we paint the ugly one on the wall, the question is: What size is it? what is in it? what CR ? What heads? what carbs? what exhaust? and what transmission?

Then we can begin to make a picture about how and why.

T

[E4ODnut]

1976 Westfalia. ~ 4200 lbs loaded weight. Maximum cruising speed @ ~ 60 MPH ~ 3200 RPM. Location elevation ~ 1700 ft above sea level.
Type 4 engine. 2258 CC, 96 mm bore. 78 mm stroker crank. Brothers Machine power master ported heads, 44 mm intake, 37.5 mm exhaust. Stock 1.3:1 ratio rockers with swivel feet. Stock aluminium push rods and solid lifters. Compression ratio ~ 8.3:1. Dual HPMX 40 carbs, 38 mm venturis. Monza exhaust. Stock transmission and tire size. He has installed a large auxiliary oil cooler with inlet and outlet temperature gauges as well as a cylinder head temperature gauge.

My feeling is that the cam should be selected to have a relatively flat torque curve peaking at ~ 3000 RPM. Idle quality and off idle torque is very important. Anything above ~4200 RPM is not important because it is highly unlikely that the engine will ever go there.

[Alstrup]

[E4ODnut]

I do know the specs on the installed cam, but I'd sooner just leave that out of the picture for the time being.

If you have suggestions as to what he should have done I'd be most interested to hear them.

[dawie]

VW type 4 bus cam- (1700 automatic and all later 1800-2L solid lifters, both auto and manual):

At 1mm lift: (0.04 inch)

Inlet opens: 2deg btdc
Inlet closes: 35 deg abdc
Exh opens: 35 deg bbdc
Exh closes: 5 deg atdc

(1700 manual had different cam timing, and max power there is 66hp at 4800 rpm instead of 62hp at 4200 for the 1700 auto).

"Horrible hot-running hydraulic" Vanagon cam:

Inlet opens: 2deg btdc
Inlet closes: 33deg abdc
Exh opens: 36 deg bbdc
Exh closes: 3deg BTDC (note, not atdc).
Problem here is early closing of exhaust valve. Possibly meant to trap some exhaust gas in the camber at full load for reduced nox-emissions.
Note that it has -1 deg overlap at 1mm, the 411/914 cam has 16 degs overlap and the stock type 1- 1300-1600 has around 12degs overlap at the same 1mm lift.

411-914 D-jet cam:

Inlet opens: 12 deg btdc
Inlet closes: 42 deg abdc
Exh opens: 43 deg bbdc
Exh closes: 4 deg atdc.

Just for interest's sake, the 2.1 WBX DJ-series Vanagon (112hp)
Inlet valve is only 40mm, and closes at 48 deg abdc. And it still makes good torque at low revs.

These are VW's specs, as per various publications.
Remember that this is at 1mm lift. Also, this is not the full picture, as total lift and ramp speed is different as well.

I just gave these specs because you asked. As others mentioned, probably best to avoid the bus cams.

Remember that at very low rpm's, oil pressure is low, and cooling airflow not optimum. Personally i would never use an "early closing inlet valve" (high torque at off-idle), type cam on an aircooled bus engine. Later inlet valve closing opens the way for higher compression ratio, and helps protect the engine at lower rpm's. Rather do gearshifting than lugging your engine.

What is your deck height? Assume it has manual transmission?

[E4ODnut]

dawie,
Thanks very much for the numbers. Do you have the lift at cam, or lift at valve with 1.3:1 rockers?

I don't know what his deck height is, but he calculated the compression ratio to be ~ 8.3:1 if that's what you are looking for.

Stock manual 4 speed.

Off idle torque is important because the bus has to crawl around for short periods of time in fairly rough off road areas. No low end torque makes for abused clutches.

Your point about keeping the steady state revs up is well taken, but I would expect ~2500 to ~ 3000 should be sufficient.

[Randy in Maine]

I think I would be looking a "non stock" camshaft as your engine is not exactly stock.

A more correct camshaft (along with lifters to match the camshaft) would allow you to take more advantage of the changes you have made.

[udidwht]

[Alstrup]

Yeah, it almost hard to build an engine that will not make power above 4200
Nut, drop me a pm and I´ll give you a proper answer in the weekend.

T

[E4ODnut]

Unfortunately I'm not in a position to start from scratch on this build. Rather, I'm trying to salvage what we can. It is a compromise for sure.

As for the mild port heads and big valves, I wouldn't have gone that route, but in the big picture, do they really hurt in the power range we want? I think not much.

I agree the vent size is probably too large, but that's the smallest he had at the time we were tuning. It's a tuning thing and easy to correct with new parts. For that matter, I'm not sure that I would have chosen that carb set up, but I think it can be made to work well for him with proper tuning.

If I seem hung up on stock cam specs it's only because we want to run this engine in the RPM range that I expect the engine was designed for. VW engineers aren't stupid, but they do have a lot of things to take into consideration. Performance, economy, engine life, production cost, and emissions, to mention a few. It's all a compromise.

He was advised to go with a larger bore and stroke. I agree with that. Displacement makes torque and he needs torque. Just how much torque it will make and at what point in the RPM range is a function of many factors, not the least of which is the cam grind. The object is to make as much torque as we can, in the RPM range that he will use, with the least stress on the engine to have a smooth running, dependable power plant.

I don't doubt that some aftermarket grind might better suit our needs, but having the stock specs at least gives us a base for comparison. Desktop Dyno, or most other similar programs certainly do not produce fool proof results, but they are based on sound engineering principals and are certainly a good place to start and a good source to compare components as long as the input data is sound.

[udidwht]

[E4ODnut]

I've read about Jake Raby. I've prowled about on his forum and joined it about a month ago to post some questions to a type 4 expert. To date I haven't been able to post. No response from the administrators.

He claims many good things about his "Camper Special" engine, and seems to have many supporters for it. But as yet, I have seen no specifics on what he is using, cam grind in particular. Maybe I'm just not looking hard enough or in the right places. This information would appear to be "proprietary". This might be good for his personal business, but does nothing for anyone trying to compare their engine building options. The "just trust me and buy my engine" approach might be fine or even preferable for many people, but I have a problem with it. If he does have a "special secret ingredient" then good for him, but in general, for a good street engine, the quality of the build trumps the components. I don't doubt that Jake is a good engine builder and shouldn't have to resort to "secret" components. Good engine builders are and will always be in high demand.

[Alstrup]

Well, you wohnt get any "loose" details out of him. Its either "buy the parts that you want or let us do it"
To a certain extend I understand him, especially when I think of all the crap engines coming in from the West coast. 25% of my shop time is consumed with trying to salvage what is possible to salvage from totally mismatched and very bad assembled units. I still do not understand why price and looks are the ultimate factors. To me a "180 hp" 2332 cc engine that in real life pulls 146 hp and has waaay too much mechanical noise has very bad fuel efficiency and ultimately kills itself in 10.000 miles is a very expensive engine. That is what I´m about to dive into in the next couple of days.

T

[modok]