TheSamba.com :: View topic - Engine cooling success story: tennis ball plus jetting

Sun Jun 24, 2012 7:18 am

I occasionally see that people ask questions about having their engine run cooler. I had the same problem recently, and I've made moderate improvements in my car. I did a quick search but I didn't see a sticky or a particularly prominent post to respond to, so I'm starting a new one.

Briefly history on the car: a 1972 SuperBeetle I bought it in 2006. A couple of years ago I replaced the top end and oil pump; the cylinders were painted flat black with radiator paint. Recently I got a 34PICT-4 set up and tuned for the car. The engine is a basically stock AE-series 1584. Generator, original air handling including working cooling flaps and thermostat. Doghouse oil cooler has all the tin, and all the tin is in place around the engine, including the sleds. It has standard aftermarket heater boxes. The arm of my Hoover Bit broke off, but I fabricated a sheet aluminum air dam to block air in the same place. Stock 4-speed manual trans. Decklid has the stock-for-that-year 4 vents. I do have a black plastic rain shield that goes above the vents. I have a SVDA distributor with a Pertronics points replacement unit. The carb has the smaller-hole throttle plate to go with the distributor. Fuel pump is stock mechanical shimmed to produce just a bit under 3.5 psi.

So it's not perfect, but I would imagine that it's as close to stock as many people get, and this should apply to people with fairly standard cars.

Because I just got the 34PICT-4 running, in the last few months is the first time I've been driving it on the highway for long periods. I have a dip-stick temperature sensor that I have wired to a separate light on the dash (I prefer to have my oil temp indication separate from my oil pressure). Driving on the highway, on a fairly warm day, I would start getting significant flickering on the temp light at 65 mph on the speedo (that's 62 mph according to my GPS). I was hoping it was mis-calibrated sensor, but I later pulled out my IR thermometer, and checked the temp on the side of the block; it was about 230 F. (I've cross-checked using the IR thermometer vs. a thermometer in the dip stick hole; it's within 2 or 3 degrees in all cases, and the IR thermometer is faster.)

On that same drive, I took a 1-cup measuring cup and put it under the deck lid latch (it's what I had along). That got me 5 mph--I could drive with no flickering at all at 65 on the speedo, and 70 mph with some flickering (and when measured, the temp was in the same range).

By the way, my 34PICT-4 carb had a stock jet, 127.5. I was getting about 29 mpg on that trip.

More recently, went up two jet sizes to 132.5 (I bought the 127.5-140 jet kit from CIP). In a drive on a sunny day yesterday, I was able to drive at 70 on the speedo with no temp light and 75 with some flickering. When I stopped, the block temp was 225 F. I also measured my fuel economy for the same drive; it had dropped to about 26 mpg.

So for people who want their cars to run cooler, here are two things that will make a difference. I can't emphasise the importance of the oil temp sensor enough. It's cheap, relatively easy to install, and it wil keep you from burning up your car's engine.

Here's one question for the group: at any given temp, the temp light flickers MORE when I let off the gas. That is, it's an instantaneous change. Push on gas, light flickers less, let up, light flickers more. Can it be vibration? I tried turning the sensor to different directions in the dip stick hole; made no difference. It can't be voltage, can it? It's not critical but I'm curious.

Next:
- I'm going to try the 130 jet, just to see where that puts me
- I'm also going to try fabricating something to stand the decklid up, rather than sticking something in there. It won't fall out when I open the deck lid.
- I'm going to try bracing the decklid up farther. So far it's been about an inch up at the bottom. I want to set it up 2 or 3 inches to see if that makes a significant difference.

(I'd rather not put hinge stand-offs on the decklid; I don't want to worry about getting rain directly into the engine compartment while I'm driving.)

Craig Steffen

Sun Jun 24, 2012 7:37 am

Converted to doghouse cooling this weekend..and a hoover bit too.Last weekend it was a carter rotary fuel pump to end the heat related check valve failure,so my temp battles are over.

Glenns 019 is the shit,smooth as silk...and yes if I know if I move the wires the bosch tag will show...

Sun Jun 24, 2012 9:17 am

worth every penny

http://www.summitracing.com/parts/CRT-P4070/?rtype=10

Quote: It's not critical but I'm curious.
im not sure the type sensor inside.
(bimetal thermoswitch, sure vibration)
or thermistor
or a rev. biased diode , temp probe, like home thermostats use.
but the latter 2 can very voltage sensitive. (poor cheap designs)

but that motor is hot, the IR gun dont lie. trust it.
why your motor wants more deck air.
(this smacks of , all excess cooling is gone) but why.?
not photos, so i must speculate...
my guess is the main body to tins rubbers are missing or shot.
show a photo?
that includes both of them , front and rear, they are critical parts !

read the HOTVW test last month, it proved how easy it was to overheat.
and you jetting ,?? if it rich now and still hot, you have cooling problesm

1: cooling actual
2: motor lean (no)
3: advance is not right, try plotting the advance over RPM and posting that.
the we can put advance to bed.

Quote: i have a
SVDA distributor

who;'s dizzy, correct orig, vw/bosch or a clone.?

did you use hand vacuum tool to make sure the dizzy works?
and diaphragm dont leakdown?
and then block the vacuum and race motor and see "oldvolkshome" ALL" in
mech advance? spec? (only basics here, he dont show RATES@!)

are you sure you are using the SVDA correct nipple on the carb.
some have 3 nipples. one is EGR.
and tested that nipple for correct vacuum direction and amounts?
sorry if you did all that, but the dizzy must be first right, way before you tune any carb.
if the spark is wrong, the carb will not tune.
Like an 009 they run it rich to hide the stupid flat spot, (wrong)

the 1st thing to do , is make sure the fuel burns in the combustion chamber
and not as the piston flies all the way down to the BDC..!
IF dizzy is bad, the jugs get real hot. and all excess cooling is gone.
I like to call this the After burner effect, great on jet planes, sucks in bugs.

I don't have a SVDA Bentelys timing chart. sorry, if i did, it post it.
but id not run any bug with out one. why not get one?
maybe some nice soul will post it......?????
that chart is the full rate of advance for both sides.. vacuum and mech.
you need to make sure it happens ,just as it shows.

you should post all P/N of these devices, on this engine
carb body and maker, ? german or brazil?
carb base flange numbers.
dizzy actual pn.

you post these facts , answers get way better....

the SVDA dizzy
it does 3 things (besides the starting advance and end)
it advances by load ( vacuum) if this is dead, you get horrible heat
(think about that, you burn the same fuel , it's your choice, to put that
heat to the cylinder walls, (wasted) or to the axle (heat becomes HP)

the RPM advance, is for running at max RPM.
it too is important.,the starting points and the rate it advances.
the stock bug likes aggressive advance (low CR) if not, it makes heat.

1: Mech, advance
2: vacuum advance.
3: and the RATE OF BOTH, IT'S A CURVE, AND HAS A SPEC. FOR THIS STOCK MOTOR. sorry can show it.. sadly../...

please disregard my post if all parts are on car, all parts not missing (rubbers) and carb is stock and dizzy is stock and connected and timed to spec. if not, please show which parts are not stock.

Sun Jun 24, 2012 9:56 am

chapter 2
the 74 came in 4 incarnations ( i say this in the odd change it has 74 parts)
fed , calif, MT and AT.
which one was yours.? (was here, and went to, there.....)

the fed MT has a SVDA , in calif and A/T both had a DVDA. DAY 1

the spec for the FED MT is this
and must match the carb. does it?

details count, just exactly what carb and dizzy, exactly ?

Quote: Beetle 1974 * 1600 Federal Manual Trans

Distributor: VW 043-905-205, Bosch 0231 170 034
Can Use: VW 113-905-205AL, Bosch 0231 146 101, VW 043 905 205 ZB (Mexico) (See Note Below)
Points: 01 011
Condensor: 02 074
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Parts Kit (Shims, Washers & Hardware): 059-998-211, Bosch 1237 010 007
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 059
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 7.5deg BTDC @ 800-950rpm w/strobe and w/single vacuum hose disconnected and plugged
Advance/Retard Range: Vacuum: 8-12deg Adv; Centrifugal: 7-12deg @ 1600rpm, 20-25deg @ 3800rpm
NOTE: Volkswagen (with Bosch's help) now makes this distributor in Mexico and is available brand new and ready to install. Please click this link:Beetle (Puebla, Mexico) With Points Distributor to view the specs.

there are 36 overheating causes....
lots of photos and full spec, on wrong parts on motor , will solve this.
here is the full complexity ,
you must not just mix up parts willy nilly, and not get issues.
there are ways to hack this, and there are zillion words this forum, DVDA,and SVDA. but the below worked DAY1. and did not overheat.

let me GO MACRO.
the wide view.

1 the cooling is bad (rubber missing. bad, or not interlocked with the bib? or fan is not making full flow FOR ANY REASONS.
are you letting exhaust heat , up top side? FAIL !

2 The engine is tuned too lean (or air leaks) and it lean and overheating or pinging (can ping softly) or both.

3 the SPARK ADVANCE IS ALL WRONG, this causes the AFterBURNER , EFFECT AND WILL OVERHEAT THE MOTOR,
my PO cracked a piston boss doing this stunt (dead SVSA)

yes, never run any bug gauge free, unless deep pockets or got that motor free.
for $1600 back when ,you dont get free gauges. but dont make it right,

Sun Jun 24, 2012 10:08 am

Please don't take this the wrong way, but...

Your car is still running too hot. The decklid shenanigans and the rejetting are Band-Aids, but I think I would spend time trying to find out why it's running hot instead of wondering about the flickering and the accelerator and all that. You should never have to run around with anything under the decklid to keep a stock engine at normal temp.

I'm with Candy: I would suspect a timing issue, or some missing seals. Please post pictures!

Sun Jun 24, 2012 10:22 am

x2 and concise .... very good

i think he knows that, and is just trying hard to prove that extra air helps
that stock car must not need extra air at all.
ever.
cept if you put 1000 of lead on rear seat and WOT it up pikes peak.
but no..

if he'd just post the freaking P/N,.

and a close in photo of the BIB tin (his photo lib is ZERO) he asks for help
with almost no input, but it runs a 250F.

I am sympathetic for hot running bugs. i want to save it from the sure destruction....
no starts.
no fires
no melt downs.

one guy found a way to get 50degress total advance with a SVDA.
the ports were wrong and he got full Vacuum and Mech total advance at the same time.. what a horror. (under full load too)
no photos. no p/n , no joy.

Sun Jun 24, 2012 10:30 am

Donnie strickland wrote: Please don't take this the wrong way, but...

Your car is still running too hot. The decklid shenanigans and the rejetting are Band-Aids, but I think I would spend time trying to find out why it's running hot instead of wondering about the flickering and the accelerator and all that. You should never have to run around with anything under the decklid to keep a stock engine at normal temp.

I'm with Candy: I would suspect a timing issue, or some missing seals. Please post pictures!

I wouldn't say that is completely true. For instance my 69's decklid has no vents on it; that's fine for a bone stock 1500 with a non-doghouse shroud...But now I have a 1776 with doghouse cooler and dual ICT's. The amount of air that the engine needs for cooling and breathing has to increase with the added displacement and fan size. I run with a tennis ball in the summer months because of this.

Even if your decklid has vents, it may not be adequate if you are running a big motor.

Sun Jun 24, 2012 10:38 am

And you will notice I said a stock engine.

For a 1776, I agree, but that's not what Craig's running. His is a stock 1584, with all the decklid vents.

Sun Jun 24, 2012 2:53 pm

You can run a 1776 with a closed decklid...hell folks run 2 liter engine with closed decklids.

all this distributor jazz with models and types and base idle settings...run your distributor ar 30 degrees max timing,and let the idle timing fall where it falls.

engine oil viscosity has a big effect on temp as well,the thicker the oil the more heat it holds,the higher the pressure and flow related to thicker oil causes the oil to pass through the cooler (or even bypass) faster.

driving habits greatly effect heat as well,dont flog your engine like a slave...let it work,back off it some.

all this is provided all the tins are in place and the engine is relatively clean...so many you see with an 1/8 coating of oil and dirt which acts like a blanket.

just ran mine 90 freeway miles averaging 68 mph,two adults,two kids in the car,the dipstick could be held no problem..it was hot,but could be held.

Sun Jun 24, 2012 3:08 pm

Johnnypan -
Congrads on your Oil Temp !
:)

Sun Jun 24, 2012 6:37 pm

candymustang66 wrote: if he'd just post the freaking P/N,.

and a close in photo of the BIB tin (his photo lib is ZERO) he asks for help
with almost no input, but it runs a 250F.

As a matter of fact, I didn't ask for help at all. I offered my post for anyone who wants a bit more cooling, to tell them how much more raising the deck lid or changing the jetting gets them, since people ask that all the time. Thank you for adding information about distributors and such, since those are also often issues, but don't rag on me for asking for help without providing information, 'cause I didn't.

However, since you brought it up, I'll fill in some more information.

As I said, all the tins are there, including the rear and the front breastplate tin. The rubber seals were partly disintegrated in both places when I bought the car. I replaced them both. They're not perfect, there are a couple of places where the seal flips over to the other side of the tin, and the corners aren't perfect, but there is rubber basically all along the edges of both tins.

I'm aware that I could look up all the parts that went together in a year. However, I have mis-matched parts, and I'm not going to change that. I like the simplicity of the SVDA distributor; I can basically time it statically and be almost exactly right on. I like the 34PICT-4 (not -3) that I have, because it gives better acceleration when the engine's cold than the 34PICT-3; but the 34PICT-4 was california-only and was only ever paired with a DVDA. The carb with the original throttle plate (with 5/32 hole) ran like crap with that distributor. I swapped in a throttle plate with a 1/8 hole from a 34PICT-3, and it runs great.

I have checked the can on that distributor in the past, but not lately. I seem to recall it worked as I expected.

Yes I'm using the correct vacuum port on the carburetor (the unused ones are plugged).

I don't know what distributor I have other than it's SVDA. I will have to look at the part number. I suppose I will check the advance curve, but I'll need to have some way to look up what it's supposed to be.

By the way--no-one try to help me asked the most important question. All of the things we've talked about, timing, carburetion, torque, etc., are all entirely dependent on the most important parameter of the engine: compression ratio. If you don't know that, nothing else matters. As for my engine, the CR (as close as I can measure it) is 7.54. Stock for that year is 7.3; it was 7.5 a year earlier.

For completeness' sake, I'll post part numbers when I don't have company over; that will be a day or so.

Craig Steffen

Sun Jun 24, 2012 7:12 pm

gevmage wrote: By the way--no-one try to help me asked the most important question. All of the things we've talked about, timing, carburetion, torque, etc., are all entirely dependent on the most important parameter of the engine: compression ratio. If you don't know that, nothing else matters. As for my engine, the CR (as close as I can measure it) is 7.54. Stock for that year is 7.3; it was 7.5 a year earlier.

Craig Steffen

I didn't ask, because you said of your motor...

gevmage wrote: So it's not perfect, but I would imagine that it's as close to stock as many people get, and this should apply to people with fairly standard cars.

Craig Steffen

I can only speak for myself, but I appreciate all of your info about your mods, and how much difference each one makes. This is the sort of hard data which is always so scarce on any automotive site, TheSamba.com included.

You doubtless take great enjoyment in your VW, as do all Samba members. I just don't want to see a motor burned up if the cause(es) can be corrected.

Nothing wrong with using a SVDA. That's what I run! :)

The curve itself is not so important, as long as the drivability suits you. The total advance, however, does matter.

Have you checked the degrees of total advance with a strobe?

Sun Jun 24, 2012 7:26 pm

Donnie strickland wrote:
I didn't ask, because you said of your motor...

gevmage wrote: So it's not perfect, but I would imagine that it's as close to stock as many people get, and this should apply to people with fairly standard cars.

Craig Steffen

I can only speak for myself, but I appreciate all of your info about your mods, and how much difference each one makes. This is the sort of hard data which is always so scarce on any automotive site, TheSamba.com included.

Point taken; I should have mentioned it, but I didn't think of it. Frankly my motor's CR is almost the same as a stock one from 1 year before; to do that, I had to put in .030 shims under the cylinders. I suspect that lots of folks just put in new cylinders or heads without measuring anything, and end up with 8.0 or 8.1 for their CR (what I would have had with no shims) and wonder why the engine runs hot.

Quote:
The curve itself is not so important, as long as the drivability suits you. The total advance, however, does matter.

Have you checked the degrees of total advance with a strobe?
I think I have, even with this distributor, but it's been awhile. I should have some time this week to do that.

Craig Steffen