How would I know if my 914 is overheating?, Here we go... Options

[1972 914 2.0]

This may sound like an odd and silly question but here it goes:
How do I know if my 914 is overheating?
I just rebuilt the motor over the summer: 2.0L, Euro pistons/cylinders, mild WebCam, new bearings throughout, rebuilt heads, Weber 40s, running 20W-50 Valvoline conventional.
Its a 72 914 with no gauge or anything to indicate temperature.

The reason I ask this question is I've been having some rough running issues lately (past week or two). Before that the car was running an absolute treat.
Symptoms: rough running, hesitant, irregular idle, and it wont rev smoothly.
I think its ignition (just ordered new distributor, coil, and pertronix yesterday) or fuel.

The reason I think its overheating is it seems to run fine for the first 10ish minutes I drive it runs fine and even warms up fine.
And then its like a switch is flicked: I put up to a stop sign or change gear and it starts running like shite.
Either way I'm changing the ignition components but if its over heating then I don't want to drive it until figure that out.

So heres a conundrum for all you teener-heads to ponder while you sneak off to the garage to avoid your relatives on this beautiful holiday. (IMG:style_emoticons/default/type.gif) (IMG:style_emoticons/default/hide.gif)

Oh and Happy Thanksgiving!

[sb914]

This may sound like an odd and silly question but here it goes:
How do I know if my 914 is overheating?

buy a gauge or Mainely dipstick (IMG:style_emoticons/default/confused24.gif)

[Montreal914]

Well, after spending money and time to properly rebuild your engine you might want to think about some monitoring devices. I would invest in an oil temp, cylinder head and AFM gauge in order to see how you are running and tuned.
Many things can be off after a complete and modified rebuild.
Of course, everything related to ignition should also be in top notch condition.
Timing mark on the pulley is not a sure bet either.
Many things to look into, one at a time...
Good luck.

[toon1]

Get a CHT gauge pronto.

Dakota digital is a great gauge but its pricy. Money well spent if it keeps you from blowing a freshly built motor.

[thelogo]

Also wonder about this

With my bone stock 73.1.7

Really is no provision for temp the car is at


Mechanic told me just to not use bad judgement ( driving out to Laughlin in middle of summer , etc)

And to shut it down if red oil light ever comes on




Don't really know how exactly these cars over heat but





???




Please define effect of oil heat vs cyclinder head heat

[BeatNavy]

Get a CHT gauge pronto.

Dakota digital is a great gauge but its pricy. Money well spent if it keeps you from blowing a freshly built motor.

(IMG:style_emoticons/default/agree.gif) Don't guess. Get peace of mind or at least know for sure. Dakota Digital is a good setup.

Please define effect of oil heat vs cyclinder head heat

Oil temperature largely dependent on effectiveness of your oil cooling system, ambient temp, and how hard you're driving (which causes friction). As your oil gets hot (225 and north) viscosity breaks down. You'll either need to change oil much more frequently or end up destroying bearings.

Head temps are a function of tuning and load, but also dependent on whether you have a functioning cooling system: tin in place, rubber seals, fan without missing blades, etc. It can also be dependent upon how you drive. Those RPM's mean your fan is pushing more cooling air over the heads. As you approach and exceed 400F on your heads you're in real danger of damaging them and the whole valve train.

Worth Reading: Oil & Head Temps

[r_towle]

What are you running, carbs or FI?

If carbs, do you have phenolic spacers between the head and manifold, and manifold and carb?
Carbs can heat sync pretty fast if not separated properly from the engine.
Hot carbs can boil the fuel.
Also, look at the whole fuel system for heat sync potential....line routing, pump location etc.

Also, when hot, see if you can move the advance plates on the distributor, which may be moot if you already ordered a new distributor...

Rich

[Dave_Darling]

John Muir tells us that you should just be able to hold the dipstick, maybe passing it from hand to hand. If you the dipstick is too hot for that, then the engine is too hot.

I haven't actually tried calibrating my hands for that, though.

--DD

[1972 914 2.0]

John Muir tells us that you should just be able to hold the dipstick, maybe passing it from hand to hand. If you the dipstick is too hot for that, then the engine is too hot.

I haven't actually tried calibrating my hands for that, though.

--DD

I remember reading that. "How To Keep Your VW Alive"!
I've tried that test and it seems to be fine. Although I usually tend to be less sensitive to hot surfaces.

[1972 914 2.0]

What are you running, carbs or FI?

If carbs, do you have phenolic spacers between the head and manifold, and manifold and carb?
Carbs can heat sync pretty fast if not separated properly from the engine.
Hot carbs can boil the fuel.
Also, look at the whole fuel system for heat sync potential....line routing, pump location etc.

Also, when hot, see if you can move the advance plates on the distributor, which may be moot if you already ordered a new distributor...

Rich

Yes I do have the spacers under the manifolds. I'm running Weber 40s
Good thought Rich, I'll have a look at the fuel line routing tomorrow.
I was also thinking mechanical advance (suggested by my father as well) but I keep forgetting to check it.
New distributor on the way anyway but I would still like to know whats causing the issue.

[1972 914 2.0]

And yes, I will be investing in at least a temp gauge and sensor this winter.
Just need the cash!

[r_towle]

How old is the distributor?
Ever been taken apart and cleaned, then re greased?
Does the rotor move by hand easily?

You can wait until you replace it, but you could also search here for a thread.
http://www.914world.com/bbs2/index.php?sho...c=70988&hl=

[1972 914 2.0]

How old is the distributor?
Ever been taken apart and cleaned, then re greased?
Does the rotor move by hand easily?

You can wait until you replace it, but you could also search here for a thread.
http://www.914world.com/bbs2/index.php?sho...c=70988&hl=

Its the Bosch 009 unit, if its not original then its very old.
It probably needs to be taken apart
The rotor moves by hand but there seems to be a fair amount of play in the shaft

[era vulgaris]

What rpm do you cruise at?
If you're regularly cruising below 3,000rpm then you're in serious danger of overheating your heads, especially if you're doing that uphill. Cruising should be done between 3,000 and 4,000 rpm to keep the cooling fan speed going fast enough to cool the heads.

If you get a head temp gauge, I'd highly recommend getting a digital one with a sensor that fits under the spark plug. You'd be amazed at how quickly head temps can change, and the digital gauge shows the exact number so you know for sure.

[BeatNavy]

You'd be amazed at how quickly head temps can change

Indeed. And you'll probably start using the transmission to brake more.