HELP- mild HP engine Overheating-

Hi guys just installed my new engine. 1916cc, engle 120, twin 40idfs, 044 heads - Good HP, V quick!!
BUT
The thing is overheating terribly even when taking it easy I get 10 minutes before I need to park it and wait 1/2 an hour. So hot yu can't even hold the oily end of the dipstick!
Q1. I have the std dog house cooler and it is not enough. I have added a remote oil cooler in the rear wheel well but it did not help (no air flow I guess). Where does one mount remote oil coolers on the replica speedsters?
Q2. Is there an issue with the oil pump when it comes to long plumbing lines if I mount the cooler near the front?
Q3. Has enyone ducted cool air from underneath the car into the fan intake? Any piCs on how to do it?
PLease help me avoid lunching my engine!!!

How do you US guys get thumpin big engines in your speedsters and keep themdrivable???

1. how do you know you are "overheating"? Pinging? power loss? what's the symptoms?
2. The oil cooler in the front is the best position. Oil pump psi is the same 1 foot away
from the pump or 8 feet.
3. Lots of people have ducted the fan intake to a hole cut in the firewall
If you are actually overheating there are plenty of things that could be giving you issues
and you are jumping ahead trying to fix a problem that was caused by you, the engine builder or other. Timing, fuel ratio's have a huge effect on temp/perfromance. Is your engine compartment sealed properly top to bottom. Separating the cooling air above from the heated exhaust air below? What type of exhaust do you have?

Apron sealed well.
Exhaust is empi hideaway type venting down and away from engine.
There is however a big gap fwd of the fan to the firewalland I can see the ground!
Also my deck lid appears quite restrictive in terms of getting fresh air in from the top.
Wondering if I am not sucking thru the top and maybe getting too much hot air from the bottom.
Duplicated this post at

http://speedsterowners.com/forum/readmsg.asp?t=12655

Please respond on that one.

There is no signs of pinging. Timing is set correctly.
Carbs seem fine too. Not lean or rich. Yet to verify O2 exhaust mixture wit a computer yet. On the cards for this week.

The oily end of the dip stick should be about 180 to 210 degrees. Too hot to hold. Do you have any gauges. Along with the oil temp, Its good to also monitor your head temp.
Yes its a good idea to seal the engine compartment
Also being a new engine its still being broken in. My 1776 ran hot in the beginning.
Also on you remote oil cooler do you have a fan? If not you could add a thermal switch and connect it to the fan.

Here's that thermostatic cutout switch Ben was talking about. Mine comes on at 180 and shuts off on its own, even if the car's off.
Wired to the battery with its own fuse; located on the hot side of the cooler.

Nick, Again, how do you "know" it's hot?

Does your shroud have the flaps and thermostat? If not, VW put them there for a reason.

Great posts above. Also try to install OEM VW cylinder tin and doghouse fan.

Once again I am going off thread topic, but Cory, how does the oil cooler work after the engine is off? Is it still flowing oil somehow? I have wondered if this was possible, like a turbo timer or something.

Sorry..

James

I've wondered that myself. The only thing I can think of is convection due to the temperature difference.

All that's "working" is his fan - it's only wired to the fan thermostat, so when he turns off the ignition, the fan is still running. Oil doesn't circulate, it just cools off in the cooler.

I would check and clean BOTH the oil galley releaf valves!!!! One may be stuck in cold run mode and not allowing oil to pass into the oil cooler.

It's more common to have one stuck the other way and have it burst the oil cooler with a over pressure situwaction. But this can happen too...

Also,,,Mainely Custom By Desizn,, offers a dip stick gauge If you want to check it in the case.

While we are on this subject. What is the ideal Oil temp target 180 ? 210? or 220.

That's a good question....

I was always told that:

170 is a bit too low

180 - 210 is just about right (because it'll get hotter on a long uphill and cool off a bit downhill or on a flat)

215 is beginning to get hot

220 is when I start sweating for it

230 is time to pull over and let it cool off for 1/2 hour

Over 230 is time to SERIOUSLY look into better cooling - what you have ain't cuttin' it.

BTW: I've been using a www.mainelycustombydesign.com dipstick thermometer for a few years now. Expensive at $50, but the best (and most accurate) way I've found to check the sump oil temp. You just can't check it while driving!! I used mine to calibrate my dash (electric) temp gauge, using fine lines in the glass.

I also have a new "Mainely" dipstick and it seems to read a pretty constant 185 to 190 after a good run. Sounds like I'm in the sweet spot.

The Speedster does offer some cooling challenges that we don't see with other cars.

I recently took a trip to Special Edition and completed two days worth of data acquisition in a new Speedster with a 1915cc T1 engine outfitted with my DTM cooling system.this was done to compare the the engine bay and fan inlet temps of the Speedster to that of an early VW Beetle as I am working on the ultimate cooling system for fit,function and cosmetics and needed this data before going further...

I am still analyzing the data, but I'll post a few graphs later this week...

Let's just say the results are drastic in comparison, BUT the highest recorded temp I saw from the 1915/ DTM was 320 CHT and 200 OT.

Since there is only a quart or so of oil in even a fairly large remote oil cooler (unlike a normal water cooled car's radiator which may have couple gallons of coolant) I would think the fan could shut off when you turn the engine off since it running after shut off would only cool a limited amount of oil. Then again - you'd hate for the quart in the cooler to bake off from high temps. I noticed (short sampling though) that Cory's fan only stays running for maybe 5-10 minutes after a good run.

Wolfgang:

I have my cooler fan wired up to the ignition circuit such that it shuts off immediately when the key is turned to off. Sounds kinda cool - you hear it wind down for a couple of seconds.

Basically, when everything is turned off, nothing happens. The engine isn't generating any more heat, so it begins to cool and the fins of the external cooler cool the oil that's in it at a slower rate than when the fan is running, but nothing big happens.

Start it up again and everything just acts normally.

Water cooled cars that have the fan running after the ignition is switched off do so to prevent the coolant from expanding too much and/or generating too much pressure so that the over-pressure valves (radiator cap) don't open or they don't rupture something (hose, radiator, heater core, etc.)

Oil temperature IS NOT ENGINE TEMPERATURE!!!!!!

In fact, they are only slightly related when analyzing data. Oil temperature is much more impacted by fan inlet temps, engine RPM(gearing) and oil effectiveness.

I have seen engines die of catastrophic failures that never had oil that was over normal operating temp...

Cooling your oil won't cool the heads.

James -- it just cools the quart that's in the cooler, that's all. It doesn't kill the battery to do it that way, and it's good for moving a little air out from under the engine compartment.
No real logical reason; the important thing was to get it to come on when the oil was at the optimum temperature and to try to hold it there.
Jake predicted -- correctly -- that I was going to need an external cooler in addition to the one I had already mounted in the shroud he made. Remember, though, my friggin engine is enormous compared to the 1641 I had.
That Type IV is a different animal altogether. Seven hundred eighty-three ccs bigger, and not intended to be cooled vertically. I'm all about listening to advice, 'cuz I never want to have to do that engine again. It's already had the top end redone once. ...

Jake, what can I use to watch engine temp? what should that temp be? Cabanaboy ~ Mahalo

Westash 1-800-400-7024 offers a aray of instuments that are aircraft grade. get the catalog
I have seen that Jake uses them alot in all aspects of his testing and even on some of his personal cars.

I have been to some of the events that he showed his stuff. OPPs.and I take pretty good shorthand. and should have been a detective.

Not tryin' to sound like I know anything, because I don't really, so I'll just repeat what I have heard before, and what I think Raby is saying, in different words: these engines are AIR cooled, not OIL cooled. I do believe it will be possible to cook your heads/valves to a very bad result while keeping everything in the sump within "noraml" range. And if you want to get down to cases, there will be a rather large temperature gradient through out the heads while operating normally. Closer to the combustion chamber will be hotter than farther away from it. Also, within a given head, closer to the exhaust valve will be hotter than farther away from it. Exhaust valve seat will run hotter than intake valve seat. You want to get even closer still, there is a gradient in temperature just going around the exhaust valve seat, because there is no symmetry in the structure: some parts are closer to the fins than others. Just the nature of the beast. So there really is no specific, constant "head" temperature. What you do is measure the head temp at some convenient place on an engine that is running "correctly". Then, you assume that all the other temps through out the engine will rise and fall in like manner with this point measurement. Then by some magic (or in Jake's words, after he massages the data) you decide what is too hot and what is OK.

If something changes in the engine to alter the heat flow, and the normal thermal gradients, then there may be hell to pay -- or if not hell, then the mechanic. Case in point: If you develop a slight unseating of the cylinder to the head and so get the tiniest bit of blow-by where the two pieces should be in good thermal contact, the temps in that area of the head are going to change dramatically, while overall, just about nothing else will be noticed: oil temps just fine, and engine running like it always has, or not so different. But right at that spot, temps are going way up. If that spot is, say, right near the exhaust valve, then the seat will heat up in a little place, and when the valve sits there a little while each cycle, it will not cool like it is supposed to. Pretty soon this little part of the exhaust valve gets too hot, and the metal starts to melt, and the valve burns just in this spot. THEN you notice the trouble. You might wonder how I know this. I still have the exhaust valve w/ the little pie-shaped piece burned out of it . . .

Again these are air cooled engines that depend on a considerable amount of heat conduction through the aluminum parts and the fins. The parts you really care about are a good ways removed from the temperature of the oil. Not saying you can't cook your oil, cause you can, for a whole bunch of reasons, so it is good to keep oil temps from going too high.

Kelly, thanks for the info, starting to understand what might be happening in my engine (loose head/cylinder)?? I'll keep you updated. Cabanaboy ~ good nite

I also have heard this, With full flow oiling a engine can tolerate hotter thinner oils and still maintain good enough lubrication to all the bearings. and thats basicly the extent of what thin oil distroys.

But head temps???

To lean a fuel mix caused by too small jets in the carbs is one culprate.

But a to restrictive exhaust system is a real killer.,and ussally that, OR a to high compression ratio which can be checked with a compression gauge, may require you to shim the jugs at the bottom to lower it ,,,are the most likely possibilties,,

Or is it a drag racing engine. They usally have high compression heads on them. You may have the wrong kind of heads installed ,,small chamber heads can do this.

What's involved in adding head temperature gauges, and are they worth the trouble?

Head temp gauges are MANDATED in every vehicle that runs one of my engines- they are that important.

Oil is a lubricant- not a coolant. If it were an effective coolant you'd be running it in the radiators of your "other" cars...

Oil temp and head temps both need to be monitored. When doing this one will see just hopw little the CHT is impacted by ambient temps, but how it is very sensitive to load when compared to oil temps.

RPM+friction=oil temp
Load+ Head temp

Either can be uncontrollable if the engine is misconfigured or ran out of tune. Tuning is the #1 cause of heat related failures with these engines.

What's involved in fitting them, and can you recommend a good source?

I've got almost the exact motor, only I have the 041 heads with big valves. I'm in Dallas and I have no overheating problems. Not running all over the freeways at 80 mph for 35 minutes at a time, nore in bumper to bumper where you go from 0 to 10 to 0 to 20 and back to 0.

Jake of Massive...
What head temp gauge set up do you Mandate? Whose gauge do you recommend? VDO? Do you have a specific location to mount the thermocouple? Under the Spark Plug with the VDO type thermocouple?
Do you monitor all cylinders? 4 gauges or 1 gauge w/digital or mechanical switch.
What temps do you consider to be normal operating range? What variation between cylinders do you consider normal? (Do Type I and Type IV have different standards?) What temps do you consider to be Max. And where do you draw the line, temperature wise to shut down and fix?
Thanks,
Greg

I stay away from the VDO gauges because they lack accuracy and are slow to respond to changes. My favored units are from www.westach.com and www.dakotadigital.com

The senders for these must go UNDER THE SPARK PLUGS- NOP WHERE ELSE IS ACCEPTABLE FOR ACCURACY as different portions of the head can be 100 degrees different and usually cooler.

250-325* is extremely good for head temps
325-375* is typical for most engines
375-400* is OK for pulling hills, but don't run at these temps for extended periods of time
400+* = Engine damage most of the time.

If a sending unit is used, what cylinder should be monitored? #1?

some systems display the highest temp of the set automatically, some continually roll thru all or you can select the cyl. of choice.

Kevin:

#3 is typically the hottest of the lot, because it is behind the oil cooling tower. The VW fan shroud designers made some concessions to this in the placement and configuration of the shroud, the moveable air vanes and the tower to move more air over the #3 head to compensate, but it is still usually the hottest.

But I have a DTM and wasn't sure if it cooled equally or if there was one single cylinder to look out for. If Jake posts here, I am certainly going to tap him for his suggestion... since it is his shroud. I was looking at the links that he sent, but I did not see a gauge that read multiple... or if there was, I did not see it. Not the best consumer-friendly web sites.