Date: Mon, 17 Jun 1996 11:35:41 -0700 (PDT)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: eugp@uclink3.berkeley.edu (Eugene C. Palmer)
Subject: RE:Troubleshooting Overheating
>From: Mike White[SMTP:MIKE.WHITE@law.utah.edu]
Sent: Monday, June 17, 1996 9:17 AM
=========================================================================
Date:
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From:
Subject: Troubleshooting Overheating...
>It's summer time once again (for those of us north of the equator),=20
>the heat has settled in, and the bus is getting cranky.
>Following St. Muir's advice I checked everything he suggests and=20
>more. Here's my list thus far of things to check to stop that=20
>overheating. PLEASE add to the list. I am stumped in finding=20
>something else to do to cool off my bus:
>=B7 No crap in cooling fan
Fan nut tight? Fan not spinning on it=92s shaft? I looked through a junk
yard for a fan awhile back, virtually all of them had rounded out fan center
holes. I=92m convinced some of these cars were in the junkyard because the
fans weren=92t spinning and the engines blew. Doesn=92t sound like you=
though.
>* Belt to generator taut
>* Engine tuned properly:
> - valves adjusted
>n timing adjusted
Timing set for the compression ratio of this engine? Distributor being
oiled properly and is not worn out or advancing incorrectly? A new dizzy
can have a completely different feel for an engine.
> - fresh oil
>n carb adjusted (adjusted slightly rich to burn cooler)
Fuel system in top shape? Strong pump, big, clean lines, non-restrictive
filter, gas tank finger screen clean, float bowl set properly. Lean
conditions kill. This is especially true with dual carbs. I destroyed an
engine with one of those silver fuel regustrictors.
> - good compression ( > 100 in my case)
> - all spark plugs are firing
>* Bottom and top of engine scrub washed clean. (It is shiny under=20
>there!)
>=B7 Oil pressure release spring and valve clean and operational
A stronger spring can help keep oil going to the stock cooler, don=92t go
crazy though.
>I've done all the above and then took it to my mechanic buddy. He's=20
>quite good, but this time was very busy and basically did a 15 minute=20
>check, ran it on his emmissions tester, and said "Since you have a=20
>1776cc and an advanced cam, it going to run warmer. Put air scoopes=20
>on the sides or drive without a deck lid"
I agree with this mechanic more or less. The 1776 is going to run hotter,
no matter what. I don=92t agree with keeping the deck lid open. An=
airtight
engine compartment should be the coolest. Scoops? Maybe.
>Last summer it passed the dipstick test just fine when running in=20
>the evenings ~75-80 degrees, and would be slightly unhappy when it=20
>was +95 degrees in the day. I do have a slightly advanced cam, but=20
>it also has drilled out oil passages, and they heat didn't seem to=20
>affect it as much last year.
Check those valves often! If they start settling real fast your in for
trouble. I check mine every morning on trips. I run them at .004 exhaust,
.005 intake since I can spot changes quickly. You get a bit more power and
less noise than if they=92re set .006.
>This year so far when driving I can feel it has a little less power=20
>when it gets hot, and after a drive I can touch the dipstick for=20
>about a half second and have to let go. It has that "hot smell"=20
>to it.
>I hesitate to do this, but last year when I tried that Valvoline=20
>synthetic it went balisitc in the heat department. This time I=20
>strayed from my Penzoil SAE30, and put in Castrol 30. It's hot=20
>again. I don't want to blame it on the oil, but I'm stumped!?
I doubt it=92s the oil. More likely the gas this year, though I haven=92t=
been
out there driving in the heat yet.
>I guess I could possibly get a thermometer and drop it down into the=20
>dipstick hole and get some real numbers.
>Can anyone add to my list of things to check to see if I missed=20
>something obvious, and maybe the list will help out someone in need.
Keep the compression at 6.7-8:1 regardless of engine size. Anyone ordering
from GEX or RMMW, etc. should specify this. It makes a bit less power if
it=92s stock, but it runs cooler. Course this doesn=92t help because the
engine=92s already built, oh well. Now we have to fix things. So the oil
galleries are opened up? The pump should be upgraded as well (30mm), this
can be done with the engine in the car. Since this is a big engine I think
a full flow external oil cooler is mandatory. A big fat one with threaded
fittings to handle the extra pressure the big pump puts out. If there is a
filter, it needs to be an HP1 or it=92ll blow with the big pump. Don=92t=
put
them anywhere the heat can get back into the engine compartment. More oil
flow means more heat transfer. A deep sump can help some, and is another
necessity for the big engine. It will eventually get almost as hot, but the
extra oil gets you a couple degrees. Be real careful about the installation
or it will leak. It might leak anyway. Heavy duty valve springs should be
in all busses, they help transfer heat from the valve to the seat. Don=92t=
go
crazy with duals though, they=92re too hard on the rest of the valve train.
At least put .1" shims under the stock springs. This is another thing
GEX/RMMW type orders should specify. Another thing Berg whines about, and
is right as far as I can see, is to not use stock heater boxes or exhaust
with a big valve head. I would put an extractor exhaust on any big engine.
Keep that air moving freely.
Eug,
=9171
