1981 Aircooled Westy w/ Cali emissions-timing running hot

[VWinVT]

Hi,

I am stumped. Now that I have installed a DD CHT gauge. As to be expected, I was running hot. I adjusted the AFM, to richen the mixture a bit to cool the motor. It worked well and solved my stalling at idle issue, I was way lean. Anyway, I now run at about 410* cruising at +/-55mph.
I decided to check the timing, and found it to be set at 10* ATDC at idle. I have also discovered that the dizzy on my van is from the 83-84 watercooled. I set my timing with hose off and idle stabilizer plug into itself to 28* BTDC at +/- 3500rpm. I eagerly went for a ride, only to discover my head temps rose to 445* at +/-55mph! I tried to readjust the AFM, but went as rich as I could go with no improvement. After a lot of trying different timings and AFM settings, I am right back to where I started from...timing set to 10*ATDC at idle (hose connected) and running a bit rich.
Why does my engine run hotter, the more I advance my timing?

Thanks for you help,
Bob

[germansupplyscott]

your timing is weird. what is total timing at 3500 when you're at 10 atdc idle?

it may or may not help your situation but i have found the CA spec injection to be pretty much impossible to tune and unless you must have a catalyst you will be much better off with a federal system. it's not difficult to switch but you need the harness, the AFM, the ECU. do you have CA exhaust? this is a problem too, the location of the catalyst is terrible, right below the left cylinder head and an awfully convoluted path. i have found what works best is '79 federal (Bus) injection components, this gets rid of the o2 sensor and idle stabilizer. the AFM is available remanufactured and they are good units. the exhaust can be converted easily to federal vanagon and this is a much better setup.

the aircooled vanagon, especially from CA always run very hot and it's more or less impossible to correct this without significant changes to the engine internals or injection components. or lose the CHT gauge and drive it.
_________________
SL

[VWinVT]

I agree the timing is weird. At full advance the timing gets to about 16* BTDC. I am in the process of seeking out vacuum leaks. I am hoping i can make improvements without major surgery...but time will tell. I can't see the motor lasting too long running at 450*

[Wildthings]

[VWinVT]

You are correct. It does run quite weak, bugs out hard on hills of any magnitude. The timing scale has a red dot at 10* ATDC, right where it is set at idle. I will read the ratwell article and be sure this is the proper mark on the pulley.
i have been doing a more thorough/methodical search for vacuum leaks using starting fluid. I have already found and fixed leaks on the PCV, vacuum hose to the dizzy and now a crack in the S boot (just ordered a new one).

[VWinVT]

I hate typing with my thumbs in the phone with auto correct...i meant to say it "bogs down hard on hills"......

[Wildthings]

With any distributor your should be able to set the timing a t 28°BTDC and have it run well. That you can't is odd. If you don't have an operating vacuum retard 10ATDC would be extremely retarded.

Pull the plug the CHT sender is on and make sure the sender looks like it was sealing. If the plug doesn't seal the sender will read very hot.

[VWinVT]

I removed the sender ring and have the crimped wire end snugged down between the Side plug wall and the head. I am going to go check it tomorrow. is it possible that this dizzy is just junk?

[WestyJP]

I'll throw a bit of encouragement in by saying that it seems likely that you can set the overall advance to what you want if the engine runs well at all with that distributor. You may end up wanting to change distributors to be able to get a curve from idle to overall advance that matches better with your engine but for the sake of dialing in highway speed power and temps stable, correct overall advance is all that really matters timing wise. The advance curve of the distributor will have more of an impact on your idle tuning and power during acceleration, partial advance, etc. not the higher-rpm performance, unless I'm mistaken. I set my overall advance to 32 degrees years ago and have had great head temps consistently though you may be safer with 30 or 28 degrees overall and each engine prefers a touch different tuning I imagine.

In my experience once you get the overall advance set to what your engine is happy with you are done in terms of tuning highway speed power and temps with timing. From there you can focus on the air/fuel ratio primarily as long as there aren't other things that are out of whack. You may be resistant to buying another guage but adding an air fuel ratio guage can help you tune the air fuel ratio properly and remove another huge variable from the troubleshooting mix. I'd not drive an air cooled without one but they are a bit pricey and involved to install so I understand why most don't have them.

I can cruise highway speeds in almost any conditions without the head temps going above 350 degrees. I just drove from the Atlantic to the Pacific and back in North America and this was true everywhere but a few times when the head temps went up to 360 or 370 pushing long mountains. Oil temps creep up and I had to add an oil cooler with a fan to keep them under control when it's really hot out. Head temps are easier once the engine is tuned in my experience. I'm running a stock Boston Bob engine with 90k miles on it and tuning the dizzy and the AFM were the biggest steps to controlling temps. I run 13.6 air/fuel and that has worked well though I have to adjust it as altitude changes on my van (federal).

Hope that info helps a bit. You should be able to get performance and temps to acceptable levels without too much more effort and there are plenty of great folks and ideas on here to pull it off with an old air cooler.

Good luck with it,

[VWinVT]

[VWinVT]

By George I've got it!!! After re-reading Ratwell's 'how-to' on finding the timing mark; I couldn't wait till morning to check. Glad I did. It turns out that a PO had painted the 2nd notch on the pulley and used it as TDC to time the motor. This means, my current timing setup is way far advanced and when I advanced it it was off the chart! Soooo, I will remove the marks on the 2nd notch and mark the 1st and proper notch and re-time the motor correctly...as soon as my new S boot arrives.
Wildthings, thank you for telling my to re-read and recheck the timing mark.

[Wildthings]

Pictures would be nice

[VWinVT]

I'll take some with my phone while I work in it. Ive yet to attempt a pic post so that may be an adventure too!
And for those of us using a basic tape measure....42mm is roughly equal to 1 5/8 inches.

[germansupplyscott]

glad you found something. there had to be something vital wrong.

there are not two notches on the pulley. not sure where you're getting that from but there should be one notch. if you have another notch it was made by someone not the factory. no idea what ratwell means about dowels. i looked at the photos and i can't comprehend what's meant by dowel #1 and #2.

also, it's a bit of a cavalier suggestion to 'separate the fan and pulley' to paint them. the fan is factory balanced and separating will upset the balance. unless you're taking the re-assembled fan to be properly balanced i wouldn't take it apart. cleaning it is a really good idea, they can be very dirty and therefore inefficient.
_________________
SL

[Wildthings]

[VWinVT]

I agree, I am definitely not taking the fan apart. I thought that the dowels showed the 2 timing marks on the pulley, nut I guess that is not the case. Anyway, I found the bolt and measured the 42mm and there is the notch. It is about 3 inches CCW of the notch that has been marked by a PO. Now, is there any way this could have been disassembled at some point and put back together 'wrong'...resulting in the factory timing mark being no longer TDC?

[Wildthings]

[VWinVT]

Sweet! I have a Porscheagon!!! I am just glad I found this, so I did not do any more damage to the motor. I'm going to try to get a photo up today, for visual confirmation that I am correcting this issue properly.

[VWinVT]

Well, here it is; my pulley and fan set-up. In the lower left portion of the photo, you can see the white paint dot. This corresponds with the notch that the PO and I have been using to try to time the motor. CCW from this mark, you will see a small piece of duct tape indicating the location of the factory timing mark that measures 42mm (+/- 1 5/8 inches) CW from the bolt seen behind the belt opposite the 'key' in the fan.

[Wildthings]

Do you have a timing scale?

A necessary part if you want your engine to run well. They are available through Bus Depot and others.