Replacing the cam (Type IV)

fido · Post by **fido** » Thu Feb 22, 2007 2:35 pm

I love my auto.. It changes from 2 into 3rd at 4500 rpm - perfectly right, landing you at 3000 rpm in top gear. It does wait till 2200 rpm to downshift from 3 into 2, which I think is a bit too low, but all it takes is to tug the gear lever back into 2 (which you have to do on a manual anyway) and you are there! Push it back to D and it'll wait until the throttle is light or 4500 rpm or so and go back to D (or 5200 rpm with kickdown). Same with deceleration - hit 50 mph and bring the lever back to 2 (no need to even press the button or pull the button up), she'll drop into 2nd gear and give very nice engine breaking. Only thing different is you dont need to use the clutch pedal!

BTW, the torque converter is also aircooled (has tubes welded on to pass airflow over the converter surface), so as the heads cool nicely with the engine breaking, so does the tranny! I have found that the transmission tends to be more efficient in the heat (70 F upwards) - e.g. in the summer I run 60 mph at 3400 rpm, but in the winter (<40 F) I'm seeing 3600 rpm at the same speed and fuel economy is down a few mpg. That box also dumps its heat into the engine pretty well when you park up - you can see the oil temp going up more than you expect...

Another nice thing is they give you an extra 100 rpm or so when under load - can help push the engine into the optimum rpm torque range if you are careful :)

spiffy · Post by **spiffy** » Thu Feb 22, 2007 2:53 pm

Be careful to not lug the engine in third though...around hilly areas behind a manual tranny 2.0 the manual kicks my butt every time. 3rd gear does not pull well under 55mph so to avoid lugging it I must slow down to around 47mph and pop it into 2nd....by that time the manual 2.0 has managed a better pull up the hill in fourth gear and has pulled ahead of me.

They do great around town though....I just wish I had a '2.5' gear for the hills.

fido · Post by **fido** » Thu Feb 22, 2007 3:25 pm

I have the earlier 003 tranny and some dellorto carbs - mine doesnt like pulling below 2800 rpm (head temps rise quick), but that fits in well with my tranny (2800 rpm in 3rd is 45, which is 4000 or so in 2nd - she shifts up naturally at 50 mph, 3000 rpm in 3rd). It loves 4500-4800 rpm too (never over 360* head temps here). The joy of a 1700 with that higher torque peak and HP peak. Only drawback is top end is limited to around 70-75 absolute max before the heads heat up to near 380-400. I usually keep to 65-67, where it is around the 3800 rpm cooling sweetspot. I guess these vehicles are not the most aerodynamic...

chitwnvw · Post by **chitwnvw** » Thu Feb 22, 2007 4:05 pm

fido wrote:The joy of a 1700 with that higher torque peak and HP peak.

Is that the advantage of the 1.7? I knew I'd read something somewhere.

What exactly does that mean higher torque peak and HP peak?

vwlover77 · Post by **vwlover77** » Thu Feb 22, 2007 4:43 pm

Engines do not make their rated horsepower or torque at all engine RPM. The horsepower usually starts low and builds up as RPM increases, hits a peak, then drops off again as RPM goes over that. Torque does the same thing, but is a little "flatter" curve usually.

The "higher peak HP and torque" of the 1700 engine means it reaches its horespower and torque peak at a higher engine RPM than the 2 liter, for example. But, the peak values of the 1700 are less than the peak values of the 2 liter, I believe.

fido · Post by **fido** » Thu Feb 22, 2007 4:46 pm

2L peak torque is at 3000 rpm and peak HP is at 4200 rpm. i.e. after about 4500 rpm, there is no more power to be gained and you'd be better off in the next gear.

1700 bus engine has peak torque at 3200 rpm and peak hp is at 4800 rpm, so the useable powerband is slightly highewr up the rev range and you can have very useable power all the way to around 5200 rpm.

fido · Post by **fido** » Thu Feb 22, 2007 4:50 pm

1700 was 66 hp and 81ftlb torque

2L was 67hp and 101 ftlb torque.

1700 in the 411 was 80hp and 99 ftlb torque... different cam, compression ratio and fuel injection making the difference. My engine is this variant, but with dished pistons to reduce CR and carbs.

mycoleptodiscus · Post by **mycoleptodiscus** » Thu Feb 22, 2007 8:29 pm

I really do like my auto bus. I was bemoaning the fact that the bus had an auto when I bought it (the price was right) but now I really enjoy it, having driven a manual aircooled vanagon before and TrollFromDownBelow's bus when I test drove it for him, i'd even say I prefer it.

That said, my bus does run hot and I haven't been able to figure out why, but that's another story...

spiffy · Post by **spiffy** » Fri Feb 23, 2007 9:52 pm

I dealt with this 'hot running' on my auto bus and I just decided to trend the temperatures I was reading, take an occasional IR reading around the engine...valve covers, case, exhaust and my engine has been fine....and I have purposely pushed it a couple of times.....yet I still see no cokeing under the valve covers and my valve adjustments have not strayed at all for 8K miles.....I would go with what ya have and see what happens. Cause I threw all the parts and tips at I could and it didn't change the temps...just slight performance gains.

BTW I read head temps anywhere from 380 to 450 on the freeway and last summer while we were crossing the many continental divide points in Montana she held a steady 440 to 450 for awhile, I just kept the revs around 3800 or so and gave her nice easy cool downs on the downhills.

So far so good!

Whip618 · Post by **Whip618** » Fri Mar 02, 2007 2:45 pm

I have decided to change cams to see what difference the Raby 9550 will make. I pulled my motor and tranny last night and will tear down tonight and start with the reassembly tomorrow morning after a parts cleaning session. There is only 33k on my last rebuild but I am changing all the bearings and freshening the rings.

I have been running a CB cam and have not been real pleased with it which is the main reason to try a new cam this early into a rebuild. I'm hoping the new cam will get me slightly lower head temps and a little boost on the hills.

Along with the cam is a new set of 1.8 heads from RIMCO. I'll post some pics if anyone is interested.

Phil

bottomend · Post by **bottomend** » Mon Mar 05, 2007 12:25 am

Sounds like you really know what you're doing whip! Whats your background? Glad you're here and digging right in!

vwlover77 · Post by **vwlover77** » Mon Mar 05, 2007 5:57 am

Phil,

What CB cam were you running? When my engine was rebuilt the builder put in the CB high-performance 2205 "torque special" hydraulic lifter cam, even though it is not recommended for FI, which is what I have. I'd be interested in more details of which cam you had, and your experiences.

Bleyseng · Post by **Bleyseng** » Mon Mar 05, 2007 8:44 am

Whip618 wrote:I have decided to change cams to see what difference the Raby 9550 will make. I pulled my motor and tranny last night and will tear down tonight and start with the reassembly tomorrow morning after a parts cleaning session. There is only 33k on my last rebuild but I am changing all the bearings and freshening the rings.

I have been running a CB cam and have not been real pleased with it which is the main reason to try a new cam this early into a rebuild. I'm hoping the new cam will get me slightly lower head temps and a little boost on the hills.

Along with the cam is a new set of 1.8 heads from RIMCO. I'll post some pics if anyone is interested.

Phil

I switched to the Raby 9550 cam and lifters and installed new 1800 heads (w/42x36 valves) on my 2.0l. What a difference! You will have to adjust the AFR with FI or Carbs to match the better breathing of the combo.
Lower CHT's is the biggest benefit. I used to hit 400 alot and now 300-350Fmax.

Itinerant Air-Cooled

Itinerant Air-Cooled

Replacing the cam (Type IV)

FWIW