[T2] Bus running too hot.

[David Schwarze]

You have more displacement than stock which means you are burning more fuel.  You also have less metal than stock with which to dissipate heat.  I think those combine to put more stress on your secondary cooling system (oil).  I always wanted to build a de-bored engine with the 2 liter crank and 90mm pistons but never got around to it.  I think it would have been a very cool-running combo.

Now that I think about it, those 96mm kits were built for the 1700/1800 engines which had a shorter stroke so the piston pins should be lower in the pistons than the 94mm kits.  That would cause the deck height to be off when used with the 2 liter crank unless spacers were used.  Probably a pretty thick spacer.  Have you verified the deck height of your engine?  What is the compression ratio?  But if the temps were like that before the cylinder swap, maybe that is not the primary cause.

If the 009 is running cooler then the advance curve must be different, which is expected since the 009 is all mechanical.  I would try retarding the svda several degrees and see if it helps, maybe you are simply getting too much advance under light throttle.  Might also try a tank of 93 octane in case all that advance is causing some light detonation that you are not hearing.  Detonation will make the temps skyrocket.  If it runs cooler on 93, then you know you have too much advance.

David

> On Jul 12, 2014, at 1:53 PM, Merrill Lawson <merrilldlawson at yahoo.com> wrote:
> 
> I have a VW bus that's running hot, 250-255 on the hwy, when only driving about 55-60 mph max for about 15-20 min.  It's a 1976 VW bus with fuel injection.  I had a VW mechanic recently install rebuilt VW cylinder heads & valves (96mm piston & cylinder), new oil cooler and all the tins are in place.  New engine seal, too.  I thought the new heads, cylinders and oil cooler would help the oil temps but they have not.  The mechanic feels like he has tested everything that he could think of but does not have a dyno so cannot test fuel mix at highway speeds and suspects there may be an issue with either the fuel injectors (which he feels is unlikely because at idol they seem fine) or the air flow meter on the fuel injection system.
> 
> I suggested he test the distributor after reading that a bad vacuum can will cause an engine to run hot.  Just as a test he swapped my Bosch SVDA distributor with a Bosch 009 and it's running about 10-20 degrees cooler.  Do you have any idea why when swapping the Bosch SVDA distributor for a Bosch 009 it runs 10-20 degrees cooler?