Heat Soak and cooling

mnkytail · Post by **mnkytail** » Mon May 28, 2018 10:40 am

I'm running a 1600 DP engine but have the original decklid on; so I know I'm not getting enough air to cool the engine properly. I have the "SaveMyBug" oil dipstick thermostat and it has never triggered the dipstick, so the oil temp is staying at 220 or below if the dipstick is to be believed.

All the tin is in place including the hoover bit. At this time I can't afford to hunt down a convertible decklid and paint it nor can I afford to add vents to the current decklid.

While it is running she runs really well so, no vapor lock while the engine is running. Once I park it and it sits, it will be nearly impossible to start. It releases a ton of heat (heat soak) while it sits. So it seems like vapor lock after sitting.

What are the solutions/options in this situation? Not sure if greater cooling is needed or some way for heat to escape after the engine is off is needed. I'm in Houston and have temps in the mid 90's in the summer. Do I do decklid standoffs? To let heat escape?

Thanks!

1300 · Post by **1300** » Tue May 29, 2018 5:51 am

I have a 1300 I built two years ago with a square top Pierburg pump that does this occasionally. Just happened at grocery store yesterday. Bug ran fine all morning, stopped at store and no start. I pour a bottle of water on fuel pump and it starts everytime. Or leave decklid up so no heat soak occurs.
Casey

hercdriver · Post by **hercdriver** » Tue May 29, 2018 6:08 am

Mine fires right up when cool. However I have a harder time getting it started after a long drive and more than a few minutes of sitting.

This technique seems to help....

Foot off the gas pedal
Start to crank the engine (3 to 4 revolutions)
Full throttle on the gas pedal (don't pump the pedal)
Slowly let off the gas while cranking

It normally starts with the pedal coming through about the 3/4 position.
I attributed the hard start to fuel getting past the float and flooding the engine, but now I'm thinking it maybe vapor lock.

Hope this helps.

mnkytail · Post by **mnkytail** » Tue May 29, 2018 7:13 am

hercdriver I will give it a shot next time it won't fire up. Any idea why that combination works?

hercdriver · Post by **hercdriver** » Tue May 29, 2018 7:58 am

mnkytail wrote:hercdriver I will give it a shot next time it won't fire up. Any idea why that combination works?

It was a technique recommended by a long time VW driver.

I assumed that it was clearing out any excess fuel in the intake/cyclinders, but now question that assumption. Perhaps it helps clear any vapor in the system by relieving any restrictions in the fuel lines/pump/carb?

CAVEMAN · Post by **CAVEMAN** » Wed May 30, 2018 2:46 pm

I have the same setup as the op . Does a 1600 run hotter than a 1300 ?

hercdriver · Post by **hercdriver** » Wed May 30, 2018 4:16 pm

CAVEMAN wrote:I have the same setup as the op . Does a 1600 run hotter than a 1300 ?

The later model beetles came with more deck lid vents. I'm guessing that the higher horse power engines (1600) created more heat and needed more ventilation.

CAVEMAN · Post by **CAVEMAN** » Thu May 31, 2018 2:06 am

hercdriver wrote:
CAVEMAN wrote:I have the same setup as the op . Does a 1600 run hotter than a 1300 ?
The later model beetles came with more deck lid vents. I'm guessing that the higher horse power engines (1600) created more heat and needed more ventilation.

Thanks for the info . I don't care for the way it looks , but would deck lid standoffs be a viable option ?

hercdriver · Post by **hercdriver** » Thu May 31, 2018 6:33 am

CAVEMAN wrote:Thanks for the info . I don't care for the way it looks , but would deck lid standoffs be a viable option ?

I don't care for the way the standoffs look. It changes the look of the car too much. Not to mention, you shouldn't need them. The Germans are pretty good engineers and spent a lot of time designing a cooling system that didn't need it.

If you're having cooling issues, do you have all of the cooling tins in place? That matters way more than the deck lid. Is the rubber seal properly seated between the tin and the body? Is your timing correct? If your car is overheating, you'll see it when you adjust the valves (they'll be getting tighter-especially cylinder #3).

I also run the SaveMyBug oil dipstick thermostat to monitor oil temps. I can run the bug in 90* heat at highway speeds and not come close to the upper temperature limits.