TheSamba.com :: View topic - Convertible cooling issues: Time for external oil cooler?

Wed Jul 31, 2019 2:53 pm

Hello Guys,

Well just like the title suggests, I have a '71 convertible super beetle, and when the top is down, and I'm on the freeway buzzing along for more that 15-20 minutes, my bug me dipstick starts to make a fuss that it is getting pretty hot back there.

I'm thinking that it is probably time for an external oil cooler, but i'm a little bit at a loss for which one I should go with, just a lot of options out there. my engine set up is a 2110 with 40 idf webers. All my tins are in place, and seals as well. Using 10w-30 oil currently, incase anybody asks.

I recently tried the tennis all trick, and it maybe extended my "range" by about 5 minutes without me starting to get a little nervous.
No i don't have a actual oil temp gauge.

Any ideas on what oil coolers and such I should use for my Vert would be appreciated! I am getting tired not being able to drive very far with the top down.

Best

Wed Jul 31, 2019 3:16 pm

Oil coolers don't cool heads.

Maybe time to try and get more air into the compartment?
Remove the front tin, or make up a scoop?

Wed Jul 31, 2019 3:28 pm

close the open hole in the rear tin, that and the wide open preheat riser holes are
killing you. You are trying to cool the engine with hot air, doesn't work very well.

Wed Jul 31, 2019 3:31 pm

I see the ground thru the big hole where I think pre-heat used to be. You may also be pulling in hot exhaust air thru that. So maybe what Clatter said about a scoop, and close up that hole.

edit: John and I were posting at the same time. You also should do like he suggests and close up the manifold heat openings in the tin. There is also ground showing on both sides of the engine. I don't know if that is normal on a bug or not but on a bus you want all air pulled in from above, not from under the car.

Wed Jul 31, 2019 3:36 pm

cjsuner wrote: No i don't have a actual oil temp gauge.

Best

Get this, it only takes a few minutes to install. Then you'll know if you are worried over nothing.

https://www.thesamba.com/vw/classifieds/detail.php?id=1196002

Wed Jul 31, 2019 4:24 pm

He already has one of those. But they really arent worth much unless they are calibrated. They are supposed to start warning around 210 F. But I see them "all over the place" Many start warning as low as 195 and a few on the spot and another few at 220ish.
That said, hot weather, in a convertible, with the top down, is a challenge. Like said, first thing to do is to block that hole in the rear tin. Second you can drill 4-5 2" holes behind the license plate, and use a couple of extensions on the bolts so the licence plate sits 3/4" further out. Then you increase the air supply to the engine compartment and can keep the lid closed. It will work better than the tennisball trick, but most likely wohnt cure it completely. But then you know the engine gets a decent amount of air.
I see you are using an SVDA distributor. Thgat is well, but IDF´s usually do not give a proper signal for the vacum can. Have you checked that the can actually pulls the ignition back properly ?
210F is not alarmingly warm. 220+ and I would start slowing down.
If you do a lot of longer freeway rides I would agree with you that a thermostatic controlled external cooler is a good thing, because it gives you more room to use the power you have.

Wed Jul 31, 2019 4:29 pm

OP is missing the fresh air hose seals too, air leaks around the hoses where they go through the rear tin.

Wed Jul 31, 2019 4:35 pm

Does your engine have a doghouse cooler/fan shroud like a 1971 did originally??? I can't tell from your photo.

I ran stock 1600cc DP engine in my 1971 Super Convertible from its purchase in 1976 until I removed that engine and installed my just-sitting 1835cc DP engine about 2006. I say stock but it did have a 30/31 PICT carburetor and a vintage German 009 distributor, and an aftermarket fuel pump. The 1600cc engine had been out exactly once when I replaced the front oil seal and installed a new clutch disc. I never had any overheating issue with this. In 1978 I installed a 2-vent engine lid to replace the existing dented engine lid, so I installed lid standoffs at that time, and had it painted by Maaco.

Yes, it will run a little hotter with the top down.

I find with my 1835cc engine now in it (with the shroud-mounted oil cooler I've used since 1976 on this engine), that I experience hotter oil temperatures (VDO gauge) if I drive it over 75 mph on the Interstate, and sooner with the top down.

Wed Jul 31, 2019 5:24 pm

[email protected] wrote: close the open hole in the rear tin, that and the wide open preheat riser holes are
killing you. You are trying to cool the engine with hot air, doesn't work very well.

Will do, and I will also see about getting the fresh air hoses holes their proper seals. The heat riser holes are actually blocked off, but you just can't see it in this picture.

Alstrup wrote: I see you are using an SVDA distributor. Thgat is well, but IDF´s usually do not give a proper signal for the vacum can. Have you checked that the can actually pulls the ignition back properly ? How do I check that the carb is giving enough?

Cusser wrote: Does your engine have a doghouse cooler/fan shroud like a 1971 did originally??? I can't tell from your photo. Yup, it has the dog house oil cooler, with new seals all around.

Thank you for the current suggestions guys! Keep them coming, especially if you have any ideas about external oil coolers.

Wed Jul 31, 2019 7:47 pm

What is your jetting and vents like? Convertibles can be finicky, but if you're a bit off it will aggravate the issue in any bug. On a stock engine bug depending on the small details, a 127 vs a 130 main can make a giant difference and not hurt mpg. Just something else to consider.

-Frank

Wed Jul 31, 2019 8:03 pm

Frank Bassman wrote: What is your jetting and vents like? Convertibles can be finicky, but if you're a bit off it will aggravate the issue in any bug. On a stock engine bug depending on the small details, a 127 vs a 130 main can make a giant difference and not hurt mpg. Just something else to consider.

-Frank

I'm with Frank... I would bet your jetting is way off. What are they? Idle/main/airs?

Wed Jul 31, 2019 10:02 pm

cjsuner wrote: Hello Guys,

All my tins are in place, and seals as well.

The picture shows otherwise. The dipstick is right above the hole in the rear engine tin, right above the exhaust and the fan is pulling hot air through it.
The rear apron looks like it's been replaced as well-is it sealed where it should be welded shut?

What is your louver status on your rear deck lid? Are there louvers? (may have been swapped out with a standard lid over the years) Are there rain gutters inside? Could be stuffed with leaves or rat nest...

Thu Aug 01, 2019 6:50 am

yep close up all of the holes in the sheet metal. Actually get matching proper sheet metal. Then fab up one of these for the rear engine cover. Using this on my vehicle lowered my oil temps and I have reason to believe that the head temp is low also.

Thu Aug 01, 2019 8:12 am

[quote="YDBD"] cjsuner wrote: Hello Guys,

The picture shows otherwise. The dipstick is right above the hole in the rear engine tin, right above the exhaust and the fan is pulling hot air through it.
The rear apron looks like it's been replaced as well-is it sealed where it should be welded shut?

What is your louver status on your rear deck lid? Are there louvers? (may have been swapped out with a standard lid over the years) Are there rain gutters inside? Could be stuffed with leaves or rat nest...

As I mentioned above, I will get on that hole (but to my point, the tin is in place :p ) the rear apron is removable, which is where there is both a cut on each side, and it looks a bit different.

The decklid is the correct late model vert decklid, with 4 columns of louvers. No rain tray or anything like that to speak of.

@gt, I like the look of that decklid prop, I'll look into fabbing one up.

Thu Aug 01, 2019 10:48 am

The best thing I did for my early vert when running a larger than stock engine was to remove the front engine tin completely. I extended the oil cooler exit and wrapped the header tubes to reduce the amount of heat that could get pulled into the fan.

I first tried drilling a bunch of 1/2 in holes, then cut it in half and left the dog house side. The half started to rattle so removed it completely. Did the same on my early bus and kept the temps down in the desert.

Only down side is the engine gets pretty dirty if you do a lot of dirt roads.

Dont mess around, get a CHT and OT gauge otherwise you are just guessing

Sat Aug 03, 2019 10:29 pm

Setrab cool the best from what I’ve heard.

Sun Aug 04, 2019 12:40 am

If there is not enough air to cool the oil, there is not enough air to cool the heads.

Im kinda worried about my vert, the decklid still has the stock welded rain guards and the 2.2L will need a lot more than a wheezy 36r.

Yo Jason, what are your plans for keeping your big build cool?

Sun Aug 18, 2019 9:54 am

those carbs may not be providing enough fuel for that size motor, you probably are running lean, change the idle jets to a larger size and the main jets see if that helps with the temperature. Opening the deck lid really doesn't help with air intake the engine compartment was designed to create a vacuum so the fan draws in the air through the vent holes, you should have a large oil sump under the engine I have a 3 quart sump on my 2084cc but I am using 48idf's on my engine, plus I have a oil filter and a 78vane oil radiator with manual fan. My oil temp stays around 185 to 200 depending on the engine load conditions.