The biggest single mistake people make is modifying the stock tin work. The engine needs it all and the seals that go with it. Leave the shutters or flaps or what ever they call them on the engine. These are what the thermostat operates. They direct the air flow in the proper direction. I have found with a stock engine they do definately help cooling. If you have a thermostat makes sure it works, operates the flaps, and keep it as it helps maintain a steady engine temperature year round. The seal around the engine apron is the most important as the fan can suck hot air from under the car and cause the engine to run hotter.
As others have said keep the RPMS up (be reasonable) and make sure the cooling fins on the motor are clean. I have tore apart motors from the junk yard and on every one of them I don't see how the air even flowed with all the trash the fan stuck on them. Could be why they were there.
Keep your ignition timing where where it should be and you should be fine.
All the mechanics I talk to swear by Castrol GTX in 30w or 10w30. None suggest using a synthetic oil, althrough the syn aircraft oil sounds promising.
If your machine still heats up which it shouldn't you can go to a Type 4 oil cooler which bolts right up to the stock oil cooler adapter and get a sheet metal shroud to adapt it from Gene Berg. You cut off the old shroud and pop rivet the new on. The thermostat and flapper are a necessity with this conversion or the engine may run too cool.
If you are running a modified engine three things will help you keep the engine cool. Keep the compression down to about 7.5, watch yur ignition timing, and run a T4 oil cooler. If this does not fit in your envelope get a large thermotatic fan cooled aux oil cooler with a large sump. Rumors are 70% of the engine cooling is from cooling the oil. Hope this helps.
cooling question
-
stevestromberg
- Posts: 434
- Joined: Tue Mar 13, 2001 12:01 am
cooling question
I buy my AEROSHELL 80w from the local Shell oil dist. as they have sales areas the one in your local area should have it in stock if not get a Trade-A-Plane (big yellow newspaper) there are dealer who willsend it UPS. Steve
-
aussiebug
- Posts: 1520
- Joined: Wed Mar 07, 2001 12:01 am
cooling question
Hi AJM,
You've had a heap of replies here - some very useful, and some so-so.
Here's a summary.
1. Make sure ALL the engine tinware is in place, with no holes in the horizontal parts (where the cabin heater pipes used to be etc) left open - any holes here causes a lot of hot used air to leak up from underneath and mix with the nice cool air above the engine - the engine will run hot. If you don't have the cabin heaters connected, the holes in the fan shroud MUST be blocked off to prevent cooling air leaking out. Also check that the rubber washers on the plug leads are firmly seated on the tinware - no washers can increase head temps by up to 25 degrees through wasted cooling air. Makes sure all rubber seals are in good condition - the upper side of the engine must be sealed from the underside for good cooling.
2. Make sure you have the cooling flaps above the cylinders, and the thermostat which operates them. Many folks remove these, "becuase VWs don't need them". This is rubbish - VWs need the flaps and thermo very much. The thermo makes for fast and EVEN warming - even on hotter days (hot for a VW engine is 140c, not the 40c outside temp), and the flaps help direct the air where it's needed most - more to the hot running heads, and less to the cooler cylinders. No flaps means the cylinders wear out faster as they are overcooled, and the heads can crack from overheating.
3. The small deflectors under the cylinders. Look under the engine, at the gap between the cylinders, and above the pushrods - there should be a flat metal plate up against the fins. This is essential for cooling the underside of the cylinders - it forces cooling air through the underside fins, otherwise is just spills out between the cylinders. Type3 cars have "cool tins" here - an advanced version of the deflectors, which wrap around the underside of the cylinders, and can be fitted to beetles - but should not really be needed.
4. The underside tinware - the curved parts which point the used air to the rear of the car - these are essential too, otherwise you get turbulent air flow under the cylinders from the motion of the car, and this reduces cooling. The heat exchangers of normal VW exhuasts provide the outer "cover" for this underside plenum - if you have j tubes which leave this area open, make some tinware to fill the larger gap at the sides of the plenum, so ALL the used cooling air is pointed backwards.
5. If you have a later doghouse engine in an earlier car, you MUST use the louvered (slotted) engine lids. The doghouse fan is 10% larger (fatter) than the 1200/1300/1500 fan, and NEEDS the slots in the engine lid to feed it enough air. Standoff hinges for solid lids will work here too, though in my opinion, they look ugly.
6. You DON'T need fancy oils like Aeroshell or synthetic motor oils. Any good quality multigrade engine oil does a great job. Castrol GTX 20w50, Valvoline 20w50 etc works VERY well, and they are not too pricey. VW used to recommend single weight oils, but these days multigrades are very good, and suit the VW engine just fine. In a snowy climate (not your's I know) a 10w30 does just fine. Change your oil every 3000 miles - this keeps it clean and fresh. You don't have to change it more often unless you live in a dusty environment. The crankcase has slots behind the engine pulley and a sprial groove in the crankshaft which pulls in unfiltered air (positive crankcase ventilation) so it's important to change it as recommended, so that crud doesn't build up and increase wear. Synthetics work fine, but were designed for super hot turbos etc - they aren't needed in the VW engine, and will cost a lot more. You can NOT use their extended change periods (the open crankcase design is the reason - it will still get dirty). Don't use aviation oils - they contain different additive packages to suit the different fuels and operating conditions of aircraft engines. Even the so-called low lead LL100 avaiation fuel has a LOT of lead in it - up to .84gm/litre (just a lot less than previous avaition fuels) and aero oils are designed to cope with this, plus other differences in fuel design. It MAY not harm your VW engine, but why use something which it was not designed to use when there are more suitable and cheaper althernatives. Avoid cheap "supermarket" oils though - their' additive packages may contain cheap ingredients, which may not hold up to use in the slightly hotter running VW engine. A decent motor oil changed at the right time is the BEST insurance for long life you VW engine can.
7. Driving style - as others have said, don't lug the engine, keep it spinning - that doesn't mean revving it's head off either. Max heat accumuluatuion occurs at idle (lowest fan speed) and at highest rpm (where the fan is loosing efficiency and lots of heat is being generated). Don't set the idle too low - 850-900 rpm is right so he cooling fan will still work to shed the heat you just built up accelerating away from the last set of lights.
Use 3rd gear climbing longer hills, don't lug the engine in 4th - it won't save you fuel, and the fan won't be spinning fast enough to cope with the high throttle setting. 3rd gear can be used up to 60mph without damaging the engine (that's about 4500rpm).
8. Keep the car tuned correctly. There's a tuneup guide on my web site below.
9. Avoid oxygenated fuels if possible. These have MTBE, ETBE, TAME and/or alcohol in them - all containing used oxygen, so there is less "fuel" in the fuel (in California and Denver for example, 11%MTBE makes the fuel mixture 2% lean). Electronic fuel injected cars fix this on-the-run by enriching the mixture, but carby cars carn't do this. Lean mixtures make the engine run hotter. If you can't avoid oxygenated fuels, you can increase the main jet by one step - the normal 34PICT/3 has a 127.5 main jet - a 130 jet increases the fuel mixture by 2%, which nicely counteracts Cal/Denver MTBE fuel.
If you can't avoid oxygenated fuels, try different brands - most modern fuels are designed for fuel injected cars (less volatile - not so good for carburettors) and so experiementing with brand can get good results. Use the right octnae of course. The 1200and 1300 engines needs 87RON (84AKI) fuel, the 1500/1600 engine use 91RON (87AKI), but if you hear any knocking/ pinging (a distinctive harsh clicking sound when you floor the throttle at 30mph in 4th with the engine hot) go up to a higher octane.
10. Forget "deep sumps". The amount of cooling provided by the extra sump area is almost non existent. Since you still have to change the oil every 3000 miles (to keep it clean remember) you are just replacing more oil, for no additional benefit.
11. You can't easily change pulley sizes with the VW (since the generator pulley is a special split pulley, and the sizes are set to suit the full range of VW engine operations - actuall 1.75:1, which means that the fan is spinning at over 7,800rpm when the engine is at 4500rpm. You don't want the fan disintergrating, and in any case it become less efficient if you spin it faster than it was designed (airflow dynamics). Make sure though that the fan belt isn't slipping - or loose. It should have just .5 inch movement when pulled in-out in the middle. It's adjusted using the shim stack between the generator pulley halves - if you didnt' know that yet.
Hope this helps,
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html
You've had a heap of replies here - some very useful, and some so-so.
Here's a summary.
1. Make sure ALL the engine tinware is in place, with no holes in the horizontal parts (where the cabin heater pipes used to be etc) left open - any holes here causes a lot of hot used air to leak up from underneath and mix with the nice cool air above the engine - the engine will run hot. If you don't have the cabin heaters connected, the holes in the fan shroud MUST be blocked off to prevent cooling air leaking out. Also check that the rubber washers on the plug leads are firmly seated on the tinware - no washers can increase head temps by up to 25 degrees through wasted cooling air. Makes sure all rubber seals are in good condition - the upper side of the engine must be sealed from the underside for good cooling.
2. Make sure you have the cooling flaps above the cylinders, and the thermostat which operates them. Many folks remove these, "becuase VWs don't need them". This is rubbish - VWs need the flaps and thermo very much. The thermo makes for fast and EVEN warming - even on hotter days (hot for a VW engine is 140c, not the 40c outside temp), and the flaps help direct the air where it's needed most - more to the hot running heads, and less to the cooler cylinders. No flaps means the cylinders wear out faster as they are overcooled, and the heads can crack from overheating.
3. The small deflectors under the cylinders. Look under the engine, at the gap between the cylinders, and above the pushrods - there should be a flat metal plate up against the fins. This is essential for cooling the underside of the cylinders - it forces cooling air through the underside fins, otherwise is just spills out between the cylinders. Type3 cars have "cool tins" here - an advanced version of the deflectors, which wrap around the underside of the cylinders, and can be fitted to beetles - but should not really be needed.
4. The underside tinware - the curved parts which point the used air to the rear of the car - these are essential too, otherwise you get turbulent air flow under the cylinders from the motion of the car, and this reduces cooling. The heat exchangers of normal VW exhuasts provide the outer "cover" for this underside plenum - if you have j tubes which leave this area open, make some tinware to fill the larger gap at the sides of the plenum, so ALL the used cooling air is pointed backwards.
5. If you have a later doghouse engine in an earlier car, you MUST use the louvered (slotted) engine lids. The doghouse fan is 10% larger (fatter) than the 1200/1300/1500 fan, and NEEDS the slots in the engine lid to feed it enough air. Standoff hinges for solid lids will work here too, though in my opinion, they look ugly.
6. You DON'T need fancy oils like Aeroshell or synthetic motor oils. Any good quality multigrade engine oil does a great job. Castrol GTX 20w50, Valvoline 20w50 etc works VERY well, and they are not too pricey. VW used to recommend single weight oils, but these days multigrades are very good, and suit the VW engine just fine. In a snowy climate (not your's I know) a 10w30 does just fine. Change your oil every 3000 miles - this keeps it clean and fresh. You don't have to change it more often unless you live in a dusty environment. The crankcase has slots behind the engine pulley and a sprial groove in the crankshaft which pulls in unfiltered air (positive crankcase ventilation) so it's important to change it as recommended, so that crud doesn't build up and increase wear. Synthetics work fine, but were designed for super hot turbos etc - they aren't needed in the VW engine, and will cost a lot more. You can NOT use their extended change periods (the open crankcase design is the reason - it will still get dirty). Don't use aviation oils - they contain different additive packages to suit the different fuels and operating conditions of aircraft engines. Even the so-called low lead LL100 avaiation fuel has a LOT of lead in it - up to .84gm/litre (just a lot less than previous avaition fuels) and aero oils are designed to cope with this, plus other differences in fuel design. It MAY not harm your VW engine, but why use something which it was not designed to use when there are more suitable and cheaper althernatives. Avoid cheap "supermarket" oils though - their' additive packages may contain cheap ingredients, which may not hold up to use in the slightly hotter running VW engine. A decent motor oil changed at the right time is the BEST insurance for long life you VW engine can.
7. Driving style - as others have said, don't lug the engine, keep it spinning - that doesn't mean revving it's head off either. Max heat accumuluatuion occurs at idle (lowest fan speed) and at highest rpm (where the fan is loosing efficiency and lots of heat is being generated). Don't set the idle too low - 850-900 rpm is right so he cooling fan will still work to shed the heat you just built up accelerating away from the last set of lights.
Use 3rd gear climbing longer hills, don't lug the engine in 4th - it won't save you fuel, and the fan won't be spinning fast enough to cope with the high throttle setting. 3rd gear can be used up to 60mph without damaging the engine (that's about 4500rpm).
8. Keep the car tuned correctly. There's a tuneup guide on my web site below.
9. Avoid oxygenated fuels if possible. These have MTBE, ETBE, TAME and/or alcohol in them - all containing used oxygen, so there is less "fuel" in the fuel (in California and Denver for example, 11%MTBE makes the fuel mixture 2% lean). Electronic fuel injected cars fix this on-the-run by enriching the mixture, but carby cars carn't do this. Lean mixtures make the engine run hotter. If you can't avoid oxygenated fuels, you can increase the main jet by one step - the normal 34PICT/3 has a 127.5 main jet - a 130 jet increases the fuel mixture by 2%, which nicely counteracts Cal/Denver MTBE fuel.
If you can't avoid oxygenated fuels, try different brands - most modern fuels are designed for fuel injected cars (less volatile - not so good for carburettors) and so experiementing with brand can get good results. Use the right octnae of course. The 1200and 1300 engines needs 87RON (84AKI) fuel, the 1500/1600 engine use 91RON (87AKI), but if you hear any knocking/ pinging (a distinctive harsh clicking sound when you floor the throttle at 30mph in 4th with the engine hot) go up to a higher octane.
10. Forget "deep sumps". The amount of cooling provided by the extra sump area is almost non existent. Since you still have to change the oil every 3000 miles (to keep it clean remember) you are just replacing more oil, for no additional benefit.
11. You can't easily change pulley sizes with the VW (since the generator pulley is a special split pulley, and the sizes are set to suit the full range of VW engine operations - actuall 1.75:1, which means that the fan is spinning at over 7,800rpm when the engine is at 4500rpm. You don't want the fan disintergrating, and in any case it become less efficient if you spin it faster than it was designed (airflow dynamics). Make sure though that the fan belt isn't slipping - or loose. It should have just .5 inch movement when pulled in-out in the middle. It's adjusted using the shim stack between the generator pulley halves - if you didnt' know that yet.
Hope this helps,
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html
-
Tarnx
cooling question
Covered every thing I could have thought of and more. Thanks guys. I have been running T1s for thirty years and they covered things I didn't know.
-
RonsVws
- Posts: 24
- Joined: Mon Apr 23, 2001 1:01 am
cooling question
Lots of good replys, thanks Aussiebug for all of the info. I've had Bugs for 22 years and have never had a cooling problem until now with our first Vert. It's a 76, my last 10 miles home gain 2,200 ft elevation. I have told my wife to stay off the highway as it lugs the motor in 3rd. Instead I asked her to drive it on the back roads where the speed limit is 35. This helps, I will install a head temp guage this in the near future.
Thanks,
Ron
Thanks,
Ron
-
aussiebug
- Posts: 1520
- Joined: Wed Mar 07, 2001 12:01 am
cooling question
Pimpwagen - wash your mouth out!!!
You should NEVER remove the cooling flaps and thermostat - ESPECIALLY in a warm climate.
The thermostat makes for a fast and even warm-up even in warm climates. The VW head temps are around 140c, so "a warm climate" of 40c is not much different to the engine than a cool climate 20c. The thermostat and the choke are set to work together so the choke backs off as the thermostat opens the vanes - the engine warms evenly and the car drives smoothly.
When warm the cooling flaps are open they help direct air where it's needed most - more to the hotter heads and less to the cooler cylinders.
But then - if you don't mind excess wear on your cylinders because they are running too cool - you go ahead and remove the flaps and thermo - at least you'll keep the manufacturers of cylinder and pistons happy
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html
You should NEVER remove the cooling flaps and thermostat - ESPECIALLY in a warm climate.
The thermostat makes for a fast and even warm-up even in warm climates. The VW head temps are around 140c, so "a warm climate" of 40c is not much different to the engine than a cool climate 20c. The thermostat and the choke are set to work together so the choke backs off as the thermostat opens the vanes - the engine warms evenly and the car drives smoothly.
When warm the cooling flaps are open they help direct air where it's needed most - more to the hotter heads and less to the cooler cylinders.
But then - if you don't mind excess wear on your cylinders because they are running too cool - you go ahead and remove the flaps and thermo - at least you'll keep the manufacturers of cylinder and pistons happy
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html
-
frwent
- Posts: 51
- Joined: Tue Mar 06, 2001 12:01 am
cooling question
Rob and Dave, I really appreciate your post, it ought to be published. I think the thing that a lot of folks don't realize is that these little cars are so popular and durable because of the very careful and thoughtful processes that were involved in their design. Much of the technology is very old, back to pre-WWII, but most of it is very solid and well-grounded in engineering theory. It is characteristic for a lot of shade tree mechanics to think they can second guess the original designers of these cars, but they didn't get to be the 4th largest auto maker in the world by making poor products. The VW bug is one of the modern world's most significant engineering marvels and all the advice about leaving them stock, in this case the cooling design, is sound and well-intended. I have learned a lot in recent years from sites like this one, and feel that these forums have contributed greatly to my understanding of my bug. Thanks to all of you for your contributions, and let's keep the bugs moving! Fred W.
-
aussiebug
- Posts: 1520
- Joined: Wed Mar 07, 2001 12:01 am
cooling question
Hi Fred,
Thanks for the kind thoughts re the post and the web site.
I agree with you completely. The VW design is a marvel of cleverness - it looks so simple but only because huge amounts of research went into making it that way.
To all who read this I would say...
If you modify the car, YOU become the design engineer, and I for one certainly don't have the expertise or financial backing which produced 22 million of these little marvels.
You can get away with heaps of changes and the car will run, but will it run well, or last like it was intended???
If you keep the changes within the general parameters VW used - yes you'll still have a viable car which will last the distance, but step outside those parameters, and you're on your own.
For example, putting 1600 cylinders into an otherwise stock 1500 will give you a useful boost in hp and still give you long life, since that's what VW did to produce the first 1600s.
But make a 2235cc monster with twin 48IDAs ratio rockers and and 150hp, remove the cooling flaps and manifold, fit a "power pulley".... and do you REALLY expect it to last 100,000 miles between rebuilds; or be something your wife can jump in and run down to the school to pick up the kids every day?
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html
Thanks for the kind thoughts re the post and the web site.
I agree with you completely. The VW design is a marvel of cleverness - it looks so simple but only because huge amounts of research went into making it that way.
To all who read this I would say...
If you modify the car, YOU become the design engineer, and I for one certainly don't have the expertise or financial backing which produced 22 million of these little marvels.
You can get away with heaps of changes and the car will run, but will it run well, or last like it was intended???
If you keep the changes within the general parameters VW used - yes you'll still have a viable car which will last the distance, but step outside those parameters, and you're on your own.
For example, putting 1600 cylinders into an otherwise stock 1500 will give you a useful boost in hp and still give you long life, since that's what VW did to produce the first 1600s.
But make a 2235cc monster with twin 48IDAs ratio rockers and and 150hp, remove the cooling flaps and manifold, fit a "power pulley".... and do you REALLY expect it to last 100,000 miles between rebuilds; or be something your wife can jump in and run down to the school to pick up the kids every day?
Regards,
------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html