Engine running hot, 1 for the Guru's!

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Bratjie
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Engine running hot, 1 for the Guru's!

Post by Bratjie » Fri Feb 01, 2019 2:48 pm

This one has got me, any input please?

Beetle 1600cc comes in for running too hot, rings had gone and breathing,

Built and fitted new sub assembly, still running hot, (forget me not's are in place)
Changed oil cooler, removed silver dampening material from engine bay, no obstruction in fan area,

Tested against my own beetle at outside temp of 28 deg, both cars ran same distance, let idle for 15 mins each at the same time,

Using laser temp gun;

My car, block at pedestal 76deg
Customer 115deg

My car on sump plate 68 deg
Customer 96 deg

My car at pressure relief valve front 75 deg
Customer 115 deg


Wind flow felt the same on both cars at the back from tin ware, no belt slippage, fan is tightly secured at the back, normal size v belt pulley, flaps inside fan housing removed, no open holes, heater vents blocked off, any help appreciated,!


Esté robusto, ser fuerte!!!!

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74 Beetle 2.1 WBX Turbo'ed & chargecooled
1959 Karmann Ghia Lefty, soon to be turbo'ed and chargecooled

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fig
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Re: Engine running hot, 1 for the Guru's!

Post by fig » Fri Feb 01, 2019 3:43 pm

Blocked oil cooler?
Partially blocked oilways?
Timing incorrect?
Incorrect distributor?
Poorly fitting cooling tins or fan?
Obstruction or missing vanes in fan housing?
fig
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Bratjie
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Re: Engine running hot, 1 for the Guru's!

Post by Bratjie » Fri Feb 01, 2019 4:30 pm

fig wrote:
Fri Feb 01, 2019 3:43 pm
Blocked oil cooler? Replaced and checked
Partially blocked oilways? 2nd engine, new rebuilt, maybe
Timing incorrect? Timing at 12deg
Incorrect distributor? Correct ddizzy
Poorly fitting cooling tins or fan? All in order
Obstruction or missing vanes in fan housing? Checked
Esté robusto, ser fuerte!!!!

73 Beetle project
74 Beetle 2.1 WBX Turbo'ed & chargecooled
1959 Karmann Ghia Lefty, soon to be turbo'ed and chargecooled

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Re: Engine running hot, 1 for the Guru's!

Post by retrovan » Fri Feb 01, 2019 4:44 pm

You may find that she is tight.

Find a long hill and clime to the top no higher then 3000rpm.

Take temp reading at the top,

Run down hill with as little fuel as possible at 3000rpm and test again.

If you have an decrease in temp. she just needs running in, if she picks up temp. then your internal clearances are incorrect,

And she is creating internal friction.

But 1st do air leak test with starter fluid, around carb and manifold.

Herman
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fourier
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Re: Engine running hot, 1 for the Guru's!

Post by fourier » Fri Feb 01, 2019 8:10 pm

Carburettor is possibly jetted too lean.
Incorrect grade oil.
Stuck oil cooler bypass piston.
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sean
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Re: Engine running hot, 1 for the Guru's!

Post by sean » Sat Feb 02, 2019 9:15 am

Is this a twin port or a single port motor?

What size fan is installed?

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Re: Engine running hot, 1 for the Guru's!

Post by fourier » Sun Feb 03, 2019 2:16 pm

Bratjie wrote:
Fri Feb 01, 2019 4:30 pm
fig wrote:
Fri Feb 01, 2019 3:43 pm
Blocked oil cooler? Replaced and checked
Partially blocked oilways? 2nd engine, new rebuilt, maybe
Timing incorrect? Timing at 12deg
Incorrect distributor? Correct ddizzy
Poorly fitting cooling tins or fan? All in order
Obstruction or missing vanes in fan housing? Checked
Why is timing set at 12 degrees? Is this at idle, with the engine warmed up, with the vacuum advance disconnected?

Seems like timing could be too far advanced, which could cause the engine to run hot.

By the book, timing should be set at 7,5 degrees BTDC for later distributors.

As an alternative, maximum mechanical advance (vacuum advance disconnected with engine at 2500-3000rpm) can be set to around 28 degrees, to ensure the engine is not too far advanced.
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retrovan
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Re: Engine running hot, 1 for the Guru's!

Post by retrovan » Sun Feb 03, 2019 2:52 pm

As an old Toppie, I tell you this, as when young, we did not have money to buy timing lights, or dwell meters, so we had to make a plan.

Look at some old video's of the boy racers sitting in the engine bay without a bonnet, they were not being stupid or hot, they were setting the timing to get max power without overheating.

Take the car up a hill in top gear, if she pings, get out set the timing a bit back from your advance mark and try again, you will find the perfect place for the timing for YOUR engine, as not all aircooled engines are the same.

When tightening up the distributor make sure its loose to turn with effort, this will help to do a quick set when you stop with out having to grab a spanner every time.

If you get that max pull without ping, you should be spot on.

Still think you should check for sucking leaks with starter fluid 1st.

Herman
1952 Split Beetle 1835cc (Azure Blue)
1968 Fastback 2Lt.type4( Red)
1972 Low Light Bay Panel Van 2Lt type 4(White)
1975 Fleetline Panel Van 1914cc (Aqua Blue/White)
2019 MeFusco Beetle Truck

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fourier
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Re: Engine running hot, 1 for the Guru's!

Post by fourier » Sun Feb 03, 2019 3:56 pm

You have quite good ears, for an "old Toppie".... :D

Engine knock (ping) is not always audible from the driver seat. Dyno operators use knock detection devices (knock boxes) to know exactly when engine knock starts.

Hearing no ping when driving up a hill, does not mean knock is not taking place. Knock happens even before it can be heard by ear.

Your suggestion is good, as all engines are different, and will tolerate different amounts of timing. Your method will definitely tell you what the engine does not like. Perhaps back the timing off two or three extra degrees from there, just to be safe.

Alternatively, invest in active knock control. It will detect knock and adjust timing long before you can hear it knock.

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