Author Topic: Over heating nightmare.  (Read 2678 times)

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Offline rekka

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Over heating nightmare.
« on: June 06, 2014, 02:08:29 PM »
Before we begin, I have read tonnes of threads on the SAMBA relating to my problem, followed all the advice and not made any progress.

Here is what i have in my split bus.

New 2180 cc low compression, built by myself full flowed with external cooler/electric fan. FK41 low end torque cam/ 1.4:1 rockers.

Not running lean, timed to 28 degrees max advance, dual 40 weber clones.

J tubes with industrial tins, hoover bit, all factory tin, with the doghouse shroud modified by slicing the ends off to clear the carbs and welded shut again. Ive run it with the snorkels removed and filled and also with the Jake Raby recommended 1 1/2" holes in the shroud.

Ive used a 30mm oil pump and a 21 mm oil pump with no difference in temperature, just lower pressure with the 21.

I'm running a mechanical pressure gauge from the stock oil pressure switch location and the temperature gauge in the type 3 dipstick blanking plate. Temp checks out with an infra red heat gun.

I've tried 15W40 oil and then 5W20 oil.

The Bob hoover oiling mods have been done as well as the piston squirter grooves cut into the rods (which will raise oil temp I know.)

Ive tried a shorter belt with more pulley spacers to speed the fan up but not a 356 pulley. I have the correct 35mm fan,

I can drive at 50MPH on an 80 degree day and have oil temp of 125 C ( 250 F ish). I live at the top of a 2500 ft climb and have to stop halfway up to cool down. The same bus with a 1600 dual port, reduction boxes and stock size tiresmade it up fine.

I have an its in there now with 195/50/15 rear tires.

I've driven air cooled VW's for 20 years so this isn't my first rodeo but it is my first big motor.

What have I missed?????? Any input is gratefully received.
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Offline bwaz

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Re: Over heating nightmare.
« Reply #1 on: June 06, 2014, 04:13:04 PM »
I'll start by saying I know nothing on motors....... did you use a new Oil cooler with one of the dual units to keep the stock cooler?
http://www.cip1.ca/ProductDetails.asp?ProductCode=C13-17-2873

I've made the mistake of a "good used" one before, that I thought was good, but pulled it off after overheating to find it was clogged!
brian waz

Offline rekka

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Re: Over heating nightmare.
« Reply #2 on: June 06, 2014, 06:49:30 PM »
Hey Brian. I've already removed it to check and flushed through. I think i have it solved. My temp guage has gone bad. I put a heat gun on my remote cooler and freshly removed dipstick and both were 85 deg c. Perfect. Thanks for the suggestion though.
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Offline Bruce

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Re: Over heating nightmare.
« Reply #3 on: June 09, 2014, 04:17:24 PM »
, timed to 28 degrees max advance, dual 40 weber clones.

I'm running a mechanical pressure gauge from the stock oil pressure switch location ..
First, advance your timing.  Retarded timing causes high head temps because the burn is still happening when the exh opens.  Fire in the exh port causes high temps.  Give it at least 30º.  Maybe 32º.
What is your operating oil pressure?

Have you calibrated your oil temp gauge?  Comparing it with another instrument that is also not calibrated is of no value.  Best is to use your oil temp gauge to measure the temp of boiling water.  Rig up a setup, it's not hard.

Offline rekka

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Re: Over heating nightmare.
« Reply #4 on: June 10, 2014, 08:39:40 AM »
Thanks for the input Bruce. I retarded the timing as I had some pinging under heavy load. I do not know the compression ratio but was under the impression that it was pretty conservative. I probably should try it with some higher octane fuel. I didn't know that about too little advance, so thanks for the heads up. I'm going to double check the timing anyway as I've been told to put the sensor for the gun at the plug end of the wire instead of the distributor end for a more accurate result.

I'm confident in the heat gun readings now and have driven the bus for 3 hours or so and everything is working well. Oil temp is great and pressures are good with 10PSI per 1000 rpm.
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Offline Bruce

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Re: Over heating nightmare.
« Reply #5 on: June 11, 2014, 07:59:07 PM »
I've been told to put the sensor for the gun at the plug end of the wire instead of the distributor end for a more accurate result.
Now that's FUNNY!!!!
The difference measuring the timing at the spark plug vs. the dist end is 0.000015º, assuming the plug wire is about 3/4 of a meter long.
If you have pinging with proper timing, you need more octane.  Retarding the timing is the short term fix until you get to the gas station to get the right gas.

Retarded timing.  I know one guy that had a problem with his dist and was only getting 22º of total advance.  The engine ran so hot, it blistered the paint on his Beetle's rear apron.

Offline rekka

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Re: Over heating nightmare.
« Reply #6 on: June 11, 2014, 08:05:58 PM »
No, it wasn't the length of the wire, just that I might pick up rogue pulses from the other 3 wires or even the coil wire as they are so close together.
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Offline Darren

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Re: Over heating nightmare.
« Reply #7 on: June 16, 2014, 01:00:18 PM »

I just read through the thread and glad you are getting somewhere with it, however and I am confused, you say you built the engine but you dont know what the compression is?

What is the CC of the headds, and what was the deck height to which you assembled to? we can figure out the compression easily with those numbers

Cheers 


Offline rekka

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Re: Over heating nightmare.
« Reply #8 on: June 16, 2014, 01:23:47 PM »
HI Darren, I bought the motor as a brand new unused long block, It even has a pair of your heads on it. I (foolishly) initially used it as built without the full flow and extra cooler, gauges etc and developed some excessive crank endplay. So I tore it down, did all the above mods, plus had to replace bearings and have the main crank journals ground. I didn't change the spec of anything so didn't measure the C.R. or deck height etc as everything worked perfectly before (apart from the overheating). The heads had 60cc written on them with a sharpie.
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Offline Darren

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Re: Over heating nightmare.
« Reply #9 on: June 17, 2014, 10:21:52 AM »
Hi if the heads are 60cc  a deck height of .040-.060" would put the compression in the 8.8-9.2:1 range,   unless it was built intentionaly with a lot of deck hight to lower the compression more.....

If you have the octane and the pinging figured out you could also advance the timing a little more and see ho it responds. also remember that the cruise air fuel ratio and timing can play a huge roll in running temp.

have you attemted to tune or jet the carbs with a Wideband 02 sensor?  its the easiest way of eliminating the guess work.

cheers

Offline rekka

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Re: Over heating nightmare.
« Reply #10 on: June 17, 2014, 04:07:13 PM »
There are some cylinder spacers in there around 40 thou thick or so, I'm assuming to keep the compression down. The wideband is on my to do list. Waiting for a buddy to bring his home from work. I even welded the nut for the sensor into my header. Plug colours were a nice golden brown, but that is as technical as I've got so far. Super happy with the performance and the economy has been great too. The same if not better than the 1600 that came out. I'll let you know how I get on. Cheers.
Radwerx. Architectural features in wood, metal and concrete www.radwerx.ca