I'm a Clot... (9590 cam tuning thread)

[corrieb]

Many years ago, Top Gear had a feature called "I'm a Clot and I Ruined My Car" in which people were invited to send in pictures of the thousands they'd spent turning a perfectly good car into a "modified" one, which they'd basically ruined.

There have been moments over the last few weeks where I've felt like that Clot. But I'm getting ahead of myself... Let's start at the beginning.

3 years ago, I bought an air-cooled Vanagon Westfalia. I wasn't specifically seeking an air-cooled one, but it seemed like everything I was looking for - one family owned, good price, good color, no rust etc. I flew to Colorado in the middle of summer and drove it back through tortuous heat through Nevada to Oakland, CA. The owner had "rebuilt" the engine himself and had some vague stories around the transmission that I half listened to. Long story short, it made it to within 2 miles of my house before collapsing in a pool of oil. Both the engine and the transmission were shot. It was recovered to a local "specialist" who took nearly 6 months and $5k to get it back to me, running and smogged. At this point, I was stunned by the lack of efficiency of the type IV motor and this was not helped by the lack of attention to detail of the engine work they did (oil leak, bad injector etc).

Fast forward a year and roughly 6000 miles later and the engine is running well, but making an intermittent deep knocking sound. We drive the van to Seattle and back, it gets worse. I take it to a bunch of shops, none of whom can diagnose what it is... but all of whom tell me I should probably stop driving it. (Turns out it was a missing c-clip on one of the wrist pins which was working itself loose - entirely the fault of the garage who'd done the work, but outside the warranty window).

At this point, I was questioning the whole thing. I'd previously owned an ex-Dutch military 1.7 N/A diesel Vanagon that was slow, but ran like a champ, so of course I start to think about an engine swap. However, I was also consuming as much info as I could online about the type IV engine. Forums, Jake's stuff, Richard Atwell's wonderfully detailed write-ups. The more I read and the more I understood about my engine, the more I grew to respect it. Importantly, the more I read, the more I grew to understand that it didn't have to be an unreliable pig. Provided it was built and maintained correctly - and most importantly - kept in good tune - it could actually be an easily-maintainable characterful friend.

So I decide to rebuild it, "but this time I'm going to do it right". I planned to find an engine builder with a track record of experience, get them to build me a long-block and then I'll re-install it; making sure that it's all done properly.

It was at this point that I became a Clot.

I got sucked in by the idea that while I have the engine apart, I might as well upgrade it. Who wouldn't want more power, more torque, more efficiency. I read a bunch of stuff about Jake's Camper Special project, a bunch of posts from Geoff Bleyseng and others that convinced me I should take it upon myself, without any prior knowledge or experience, to spec up an engine that deviates from stock. My brain in its excitement ignored the posts about "never passing smog" or "simply couldn't dial it in" or "you need X or it'll run like crap".

To be fair to myself, I am an engineer, I love tinkering, I am comfortable repairing cars as an amateur and I believe that things can be made better with a lot of R&D. It seemed that Jake had done a ton of this kind of R&D and what I read convinced me that his 9590 cam was probably what I wanted.

So I tore into the project. I took out the engine and stripped it to a long-block. I ordered the super cam kit from the Type IV Store and mostly influenced by Geoff's posts, I specified 36x42 valves, 7.5:1 CR, stock displacement and got the whole thing balanced. I got it back from the engine builder sometime in December and with our second child's arrival imminently looming, I scrambled to put it all back together and get it fired up. At this point, I'm about another $5k in with the cam kit, engine build and other parts.

And of course it ran horribly.

I doubled checked everything, read more posts, used Colin's wonderful post on AFM adjustment http://www.itinerant-air-cooled.com/viewtopic.php?t=7761 to try to dial it in. I found a sweet spot, but it still ran like crap.

So of course I decided to make it someone else's problem and took it to some local experts. "Please double-check my work and get this thing running" I simpered as I dropped the keys off, feeling every bit the clot that I was. After a few days, they concluded - as they handed the keys back - that the cam was incompatible with stock FI (contrary to everything I'd read), that I should convert it back to hydraulic lifters - basically that I should throw it all away and start again. Not only that, but one of the pistons wasn't seating properly.

It was at this point that I was forced to contemplate what I'd done. I'd taken it upon myself to spend a ton of money based on anecdotal evidence, opinions of people I'd never met and forum threads that always ended frustratingly prematurely; and the resulting situation was now entirely my problem. I'd contracted out to an engine builder who had followed my instructions to the letter, but who bore no responsibility for actually making the thing run.

Amazingly - and I'm still not quite sure why or how - when I pulled away from the shop, the stupid thing actually ran surprisingly well. Whatever they did, it's actually kind of worked. The van feels like it has as much torque in the low/mids as it did, but seems to have a little more power in the higher revs. Nothing sensational, but definitely good enough as a starting point. It's not great starting from cold, but it's not bad either.

So that brings us to today. What's the point of all this? Well, I actually want to document where it goes from here. I promise you dear reader that I will post whatever I do, however good or bad it turns out, and I will persist with the thread so that others might benefit from the whole dumb saga. I will be installing an AFM gauge, I plan to experiment with modifying the exhaust, I plan to do some dyno runs. Most of all though, I plan to be honest.

Thanks to Geoff Bleyseng for responding to my PM cries for help. Next step is to follow his instructions for trying to get this piston to seat properly...

[Abelabelabel]

Haha. Here here - You're obsessed. Join the club. The Vanagon motor is infamous since it's not very bullet-proof in even the best of circumstances.

Keep us posted.
_________________
1991 Vanagon GL / Carat Interior / Auto - White "Daily"
1990 Vanagon Carat / manual / Cherry Red "Bella Rouge"

[IdahoDoug]

Well, to your other accomplishments, you can add bravery for laying out the tale of woe you have created for yourself by being on the "bleeding edge" of innovative engine work. I hope you are rewarded with a reliable mill at some future date. The whole point of these neat rigs is, after all is said and done, to take us to cool spots in comfort to relax and explore this beautiful world. Keep it coming.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Bleyseng]

Really it's usually just a few simple things that add up to it runs terrible.

Go slow and fix things.

Look at how your engine builder forgot a wristpin C clip retainer and it killed your engine. Small details are really important in engine building and forget those storys of how someone rebuilt their engine in the desert, with only a visegrip!
_________________
70 Ghia Black convert-9/69 build date-stock w/133k 1600 SP-barn find now with a rebuilt tranny and engine
77 Westy 2.0L w/Ljet, Camper Special engine-95hp and with LSD!(sold)
76 Porsche 914 2.1L L20c, 120hp Djet (sold)
87 Syncro Westy Titan Red 2.1L 2 knob 100k miles

[djkeev]

Well corrieb...... My hats off to you for your honesty and be Bravery!

I too rebuilt my unit (an 86).
I decided early on for complete transparency during to process.

If what I did was glorious and correct..... People who follow could learn from it.

If what I did was hopelessly wrong and ended disastrously....... People could learn from it.

I had mostly good results..... I took some ribbing and had a few "what the heck are you doing there David?!?" Comments as well.

I look forward to your discovery posts.

I'm guessing those dead end unfinished threads you mention probably didn't end well and they were too embarrassed to report that fact?

Good luck! I support you!

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[corrieb]

Thanks for the support everyone...

Confirmed today the blow-by in the one cylinder is significant. At idle you can feel the pressure pulsing out the top of the case if you take the breather off. I can't help feeling it might be better if that wasn't venting back into the engine - surely it has the same effect as a vacuum leak?

Geoff recommended I pick up some break-in oil and then run up and down from 20-60mph in 3rd gear 10 times, so that's my next task. The engine builder told me they'd broken it in (at least the cam) but I would be so much happier if this piston seated itself and I didn't have to pull the engine again.

[djkeev]

If the blow by is that significant it will show on a compression test.

Do one....... Dry and then wet.

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[corrieb]

[djkeev]

Wasn't broken in properly........ Drive it like you stole it!

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[corrieb]

I've managed to put about 300 miles or so on the van over the last couple of weeks with the Brad Penn break-in oil after 150 initial miles on Castrol GTX 20w50. I'm not yet sure whether the piston rings have seated themselves correctly, but with the (now overdue) imminent birth of our second child around the corner, I've had other things to worry about.

I did manage to sneak some time for a bit of "seat of the pants" tuning of the AFM per the instructions here: http://www.itinerant-air-cooled.com/viewtopic.php?t=7761 with encouraging results. Remarkable how sensitive the static adjustment needs to be to yield noticeable results. I ended up getting 65-75mph acceleration of around 14s, which seems reasonable. Low to medium revs are very driveable with decent pull up hills in the mid range. I've been holding off spending too much time fiddling until I get my AFR gauge in. All this was with the stock exhaust system... until today

Today I could barely conceal my delight at the new exhaust setup. The one thing I've consistently read about the longer duration cam is: Get a better-flowing exhaust. I found an awesome muffler shop in Berkeley who were able to combine the stainless header from here (https://www.vwheritage.com/shop/bay-bus/AC251704/stainless-steel-header-for-type-4-engine-1700-2000/) with the stock cat, bung for the O2 sensor and a nifty little muffler. It looks beautiful, sounds great and to my untrained behind, seems to have added some pep to the thing too. I decided to keep the stock heat exchangers - they may not be optimal, but bang-for-the-buck/hassle ratio of swapping them out just didn't seem worth it to me. If I can be bothered, it would be very interesting to dyno the difference between the old exhaust and this new setup - just to see. That's for another time though.

Next steps - get the AFR gauge installed, give it another oil change, check the valve clearances and put some more miles on it.

It's still a pretty crappy idle at cold start - needs a good 5 min warmup till it's happy. Not sure how much of that is due to the expanding pushrods and how much to do with the cold start mixture. It would be nice if there were a separate idle setting for cold vs hot... but all of this is for another day.

[spacecadet]

[corrieb]

[corrieb]

Significant progress today. I got the LM-2 AFR gauge installed and got some tuning runs in. I also checked and adjusted the valves and was pleased to note that they were only very slightly out (500 miles of break-in).

The measurements from the LM-2 are very informative and useful, but I can see that the absolute numbers in themselves are of limited use outside of the context of any one particular engine setup. Small changes seem to make a big difference! For what it's worth, here are my observations from today:

- Setting the idle mixture is an interesting balance. Too high and it bogs down on acceleration due to the swinging of the flap making the mixture too rich. Too low and it won't idle well on warm restart. AFR of just over 14:1 seems to be the happy medium here.

- It's surprisingly rich on the over-run. What I've read is that the controller should cut the fuel over a certain RPM (1700?) when decelerating, but I'm seeing AFR of around 13-13.5 on deceleration regardless of RPM. Temp sensor 2 is brand new and Temp sensor on the air filter passes the Bentley test for resistance. Deceleration valve also passes the Bentley test. What else could be wrong?

- The LM-2 was great at confirming that the dynamic setting (spring tension) on the MPS is correct. AFR is touching 14 throughout the rev range without load.

- Driving around, I'm seeing medium load around 13 - 13.5 and WOT at 12. Doesn't go much above whatever the idle mixture is set to.

The final observation is that the LM-2 is very good at telling you how much the MPS adjustments have affected things. Very small changes at the MPS seem to affect the seat-of-the-pants performance noticeably. I'm very happy with the general performance of the engine at this point, but I'd like to get some time on a dyno and really get the thing dialed in.

[a1fa]

You could always megasquirt it, and have it running right.. You are also 1/4 there with LM2.
_________________
Learn to ride. Ride to learn.

[corrieb]

[corrieb]

Some good Samba bedtime reading this evening on some pertinent topics:

This thread highlighting the differing opinions on AFR ratios: http://www.thesamba.com/vw/forum/viewtopic.php?t=609948
...led me to this thread on dyno results: http://www.thesamba.com/vw/forum/viewtopic.php?t=426641
...which then led me to this discussion on valve clearances for chromoly pushrods (which I'm pretty sure I have from the type4store cam kit) http://www.thesamba.com/vw/forum/viewtopic.php?t=447258

Conclusions:

- 60hp at the wheels is a good result for a mildly-tuned 2L engine with a stock cam. This will be a useful baseline.

- Seems like when it comes to AFR, it's basically a balance between CHTs, power and fuel consumption. You would think that getting the engine to burn fuel at close to maximum efficiency would get you a reasonable mix of all three, but maybe it's more complex than that. Unfortunately my CHT readings are not at all useful, despite my DD gauge, due to the engine builder advising that I mount the sender on the side of the cylinder head (and tapping it accordingly). Relocating it at this point with the engine in place and all the tinware located will be a PITA.

- Interesting info on the chromoly pushrod expansion. The engine builder initially advised a loose zero setting. This was reset to 0.006 by the local shop; and having read about the importance of valve clearance, I made sure to set it exactly to 0.006 myself. I'm now back to realizing that maybe the loose zero advice from the engine builder was "right" (right in the sense of being fine, rather than being "correct").

[corrieb]

I took the van out for an hour last night and got some data on the current state of tune. This particular setup feels lively and responsive and I'm going to treat it as the baseline from which adjustments are made.

Note that some of the numbers here will only be useful for relative comparisons for me, rather than being universally useful. CHT numbers for example are way out due to the DD sender being on the side of the cyl head, not under the plug (this was due to bad advice from the engine builder, not me being "clever"). Speeds are 8% out (indicated 70 is actually 75) for whatever reason. All that being said, the AFR gauge is just awesome for getting real useful data.

Test was to drive up and down the 880 around Oakland, which is relatively flat and allows for acceleration and cruise tests. Then to drive up and down the 24 towards Walnut Creek, which is a reasonably challenging hill. Note that the "death spiral" idle noted below is when the warm idle is leaned out to the point where it cannot sustain stable RPM.

Tune 1:

Environment: 55F ambient & dry, 1/3 tank fuel 2/3 tank water in van.
Engine: Stock timing (set by shop), 0.006 valve lash
MPS: Static at baseline point, Dynamic at -3 clicks, Idle 1.5 turns out.

Idle AFR:
- Leanest before idle death spiral: 13.7
- Actual during test: 13.5 early on (post warm-up). 13.9 at the end (hotter air?)

WOT AFR in 4th gear:
- 50mph 11
- 55mph 11.5
- 60mph 12
- 65mph 12.2
- 70mph 12.5

Cruise AFR in 4th:
- 50mph 13.3
- 55mph 13.5
- 60mph 14
- 65mph 13.5
- 70mph 12.8

Part throttle AFR in 4th:
- 40-50mph 13 - 13.2
- 50-60mph 12.5 - 13
- 60-70mph 13 - 13.5

Acceleration tests:
- 0-50mph 16.5s
- 50-60mph 13s
- 60-70mph 14.5s

Up Hill test:
Low 12s on approach at 65mph. Lost 4th gear at 50mph early on. 3rd gear part throttle at steady 50mph in low 12s. Back in 4th in tunnel PT at 50mph in low 13s. 252F pulling off at Fish Ranch. Could have accelerated in 3rd and in the tunnel.

Down Hill test:
13.6 (idle value) overrun the whole way down @ 60mph in 4th. Interesting that slight throttle at 60 towards the end gave 14.5. 200F at bottom.

General observations:
Feels really lively and responsive, particularly accel to 50 and accel through 1st and 2nd. Seems to deal well with hills, although 24 hill seemed to die in 4th earlier than expected. Interesting that weaker MPS spring seems to require richer idle before death spiral. Curious to see how the idle mixture impacts overall mixture. Can't test with this dynamic setting as can't idle in lower AFRs. Seems like the idle mixture dominates the lower revs/speeds; then it's too rich in the mid range (50-55mph in 4th) and then pretty much bang on around 60-70. Cold start is reasonable. Doesn't stall, but takes a while before it will keep a steady idle. CHTs (FWIW) were consistently around 220F on the flat freeway and 235F at idle once pulled over to record data.

Summary:
Drives great, but AFR numbers in mid range (50mph), idle and overrun seem too rich.

Next steps:
Tune for linear WOT across 50-70 of around 12.5. Examine effect on other parameters. Confirm suspicion that a weaker MPS spring leads to an earlier death spiral due to tendency to oscillate more easily.

[jberger]

Sounds like you have a nice little runner there. Last year I built up a 2.0 with a 2199 (says stock but my clocking shows a bit different) camshaft and a super tight deck height. Once broken it and tuned it pulls a 77 bay camper with ease all around the bay area.

That said, I would recommend you swap the head temp sensor to the #3 plug location. It is very doable with the engine in and you really need to know that information. Coupled with your AFR meter you will be able to ensure the health and longevity of that underpowered, overworked air cooled beast.

[corrieb]

[surfwagonorangevw]

jberger wrote:
That said, I would recommend you swap the head temp sensor to the #3 plug location. It is very doable with the engine in and you really need to know that information.

I would agree with this to get real cht , also will be of interest to see the difference . Though it looks like your temps are good ,you want to be sure you're not pushing 400 degrees when loaded on hills .