1981 Vanagon loss of power and over heating

FuzzyVan81

Hello everyone! As I've been restoring my 1981 Vanagon Westy for the last 8 months I've referenced The Samba many times so let me start by saying thank you Smile

The question at hand is this, I bought the Vanagon after it sat, not running, for about 8 years. After changing the fuel lines, flushing the fuel system, replacing filters, lubing the cylinders, new spark plugs, hand cranking the engine, and starting it up it ran after three tries!!! I was really surprised and happy at the time.

Since then I've adjusted the valves, changed the oil cooler seals (what a pain), replaced the valve cover seals, and replaced the oil a couple times with high quality oil and so far no major leaks and the engine runs really well... for about 10 mins. Once it gets to about 180 degrees, it starts to loose power and once it hits about 200 plus degrees I might as well get out and start pushing.

My speculation is there's a cracked cylinder, leaking compression, that opens up as the metal gets hot, but what are your thoughts?

On a side note, the exhaust has holes after the Cat and I have one or two pieces of tin missing from under each cylinder head (would that effect the heat that much though?). It passed smog and seems to idle great.

Thanks everyone!

djkeev · Posted: Wed Oct 09, 2013 4:10 pm Post subject:

Take off the catalytic Convertor.....yes, physically remove it.

Try it again.

It may have nothing to do with engine temperature but everything to do with a clogged Convertor building up back pressure and strangling the engine.

Dave
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Microbusdeluxe · Posted: Wed Oct 09, 2013 5:40 pm Post subject:

Replace that tin!! Once you get this to run after it's warmed up you will fry the motor if you have missing tin. Try the classifieds & local junk yards.
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RCB · Posted: Wed Oct 09, 2013 7:15 pm Post subject:

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50338

Have your checked the resistance of your TSII sensor? If it is shot, isn't grounded well, or the wire that connects it to the ECU is bad your engine will barely after it warms up, that is if it will run at all.

FuzzyVan81

So I replaced the tin and it's still overheating. I haven't tried removing the Cat yet because I don't know what to put in place of it (just a standard pipe, or exhaust pipe?).

I'm not sure what the TSII Sensor is either.

Any comments on doing those two things? Thanks again everyone!

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50338

TSII=Temperature Sensor #2

It should be located in the left head just in front of where the manifold bolts down. When it or the wires to it fail it causes the ECU to hold the injectors open way too long flooding the engine out. The Bentley tells how to test it and what the correct specs are.

midmo81 · Posted: Thu Oct 17, 2013 5:37 pm Post subject:

Just to review aircooled 101.
Upper tin and seals forms the box the fan draws cool air in from the side pillars. Lower tin forms the box the fan pushed the cool air over the hot cylinders along one side around the back and along the other side and down through the oil cooler.

This picture is not my engine but marked up for illustration. Note the edge seal and the heater tube being critical.

Image may have been reduced in size. Click image to view fullscreen.

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FuzzyVan81 · Posted: Mon Nov 25, 2013 1:34 pm Post subject: Over heating fixed... sort of

So I took it to my local shop (Old Volks Home, Santa Cruz) and they determined the main issue as a broken distributor. The part that's supposed to advance as the engine heats up and rpm's increase/decrease was broken. They rebuilt it and it runs waaaaayyyyyy better, maintains power at higher temps, and runs much cooler... However, it still gets to about 240.

So I installed an external oil cooler under the driver side rear wheel well with a fan, helped a lot, and now, on a cool day, it runs pretty consistent at 212 - 220.

With the oil cooler, is that going to be good enough on a hot summer day? Do those temps seem within the normal range?

Thanks again to anyone that can help!

mightyart · Posted: Mon Nov 25, 2013 1:42 pm Post subject:

Your oil temps are fine, you need to worry about Cylinder head temperature.
That's a engine killer.
Never above 400 or you'll start dropping valve seats.
Put in a NEW stock oil cooler and it'll drop the oil temps.

FuzzyVan81 · Posted: Mon Nov 25, 2013 2:06 pm Post subject:

Randy in Maine · Posted: Mon Nov 25, 2013 2:14 pm Post subject:

This is the one we use as it is the best one for monitoring CHTs.....

http://www.dakotadigital.com/index.cfm/page/ptype=...prd347.htm

buy the 18' long sender for 14mm plugs. It mounts around the spark plug.

The Temp Sensor 2 over my #3 cylinder is to allow the ECU to know what temperature the engine is to allow for the ECU to adjust the air:fuel mixture in order to lean out the mix as the engine temp goes up.

mightyart · Posted: Mon Nov 25, 2013 2:18 pm Post subject:

You have the correct setup for oil temp.
In an air cooled vanagon the head temp is critical.
There is allot of debate as to the correct temp guage to use.
I just have the standard VDO CHT guage. it's sender is on #3 spark plug. not in the holes on the head.
Read more about CHT guages here:
http://ratwell.com/technical/VDOGauges.html#cht

FuzzyVan81 · Posted: Sun Dec 15, 2013 11:57 am Post subject: CHT above 400 degrees

After temporarily installing a VDO CHT gauge and driving it up a 15 mile incline (Hwy 17 in Santa Cruz) the oil temp stayed consistent at about 215 and the CHT went from about 350 at idle/start of climb to about 450/475 during the climb.

I've heard the VDO gauges are inaccurate and my engine seems fine and seemed good on the climb (gauge was returned). I'll probably get a more accurate one listed in this stream, but my question is that it's stated the normal CHT should be about 350-375 on an air cooled engine and it's also stated that going above 400 degrees is an engine killer, so there's only 25-50 degrees of wiggle room? That seems to small of a range based on my test (CHT rose pretty fast).

What is a dangerous CHT for my 1981 air cooled Vanagon? Thanks everyone!

a1fa · Posted: Sun Dec 15, 2013 1:41 pm Post subject:

Someone said 450-475 is dangerously high.... May want to ask in aircooled specialty forums such as Colin's IAC in Type2 forum or shoptalkforums.
IAC for stock stuff..
shoptalkforums for some crazy turbocharged stuff Wink

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wolfej1 · Posted: Sun Dec 15, 2013 3:10 pm Post subject: Re: CHT above 400 degrees

a1fa · Posted: Sun Dec 15, 2013 9:07 pm Post subject:

I need to check on my CHT with microsquirt and very crazy timing...
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