Author Topic: Engine Operating Specifics (Read 3206 times)

Milkman · « **on:** May 20, 2007, 03:41:50 PM »

Well we took the '66 out for the 1st long drive of the season this weekend. I just wanted some opinions based on the gauge readings. For one thing, the RPM seems a little high to me...

Here are the specs:

1966 Beetle
1600cc
Dual 34 ICT's
019 Distributor with pertronixs
4.37 Ring & pinion tranny
165/70R15 tires (Is that stock size or close to it?)

What the gauges read today:

Ambient outside temperature: 22c
Speed: 100kph
RPM: 3400
Cylinder head temp: 370F (That seems high to me)
Oil temperature: 190F
Oil pressure: 35PSI

Sustained speed of 100KPH for about an hour there & an hour back. Does everything seem to be reading within the correct ranges? CHT & RPM both seem high to me.

Greg

egspot · « **Reply #1 on:** May 20, 2007, 05:03:12 PM »

Quote

Well we took the '66 out for the 1st long drive of the season this weekend. I just wanted some opinions based on the gauge readings. For one thing, the RPM seems a little high to me...

Here are the specs:

1966 Beetle
1600cc
Dual 34 ICT's
019 Distributor with pertronixs
4.37 Ring & pinion tranny
165/70R15 tires (Is that stock size or close to it?)

What the gauges read today:

Ambient outside temperature: 22c
Speed: 100kph
RPM: 3400
Cylinder head temp: 370F (That seems high to me)
Oil temperature: 190F
Oil pressure: 35PSI

Sustained speed of 100KPH for about an hour there & an hour back. Does everything seem to be reading within the correct ranges? CHT & RPM both seem high to me.

Greg

I am not an expert.

That rpm at 100KPH does not sound too bad with that trany and those tires. However, I think with that trany you would rev higher than a 4:12 and I think stock tires are 165 80 15 and they stand at 25.39\" so yours are probably a bit smaller.

As for the Cylinder heads temperature, I think they are hot at 370F and it seems to me that I read some literature about it and 250f-290f comes to mind.

I am sure that you will get more informative feedback from other guys soon.

Milkman · « **Reply #2 on:** May 20, 2007, 05:56:13 PM »

Would it be souly the higher RPM that is making the heads hot? All the engine tin is in place, all the engine compartment seals are new & I'm running the correct fan for the doghouse set up. I thought that was kind of hot for CHT...

Hansk · « **Reply #3 on:** May 20, 2007, 08:28:32 PM »

What do the cht's do when you come to a stop or around town or if you accelerate hard?
If they only creep up like that at those steady speeds I'd wonder if it may be a bit lean.

I remember my cht's would jump up and down . eg -hard accelerating + 30f , deccelerate - 30f , average - aprox 300f (something like this)

Milkman · « **Reply #4 on:** May 20, 2007, 09:42:06 PM »

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What do the cht's do when you come to a stop or around town or if you accelerate hard?
If they only creep up like that at those steady speeds I'd wonder if it may be a bit lean.

I remember my cht's would jump up and down . eg -hard accelerating + 30f , deccelerate - 30f , average - aprox 300f (something like this)

When I'm stopped or idling the CHT gauge sits around 250-275. When accelerating hard it goes up to around 400-420. I'm pretty sure I'm not running lean, but I can't remember what jets I have in the carbs.

One thing I did notice tonight with the engine cold though. As soon as I turn on the key the CHT gauge is already at about 125-150F. Is it possible that I could have a bad gauge? Out of calibration?

Chris · « **Reply #5 on:** May 20, 2007, 11:05:35 PM »

what type of sender is it?

Cameron · « **Reply #6 on:** May 21, 2007, 11:12:11 AM »

I would suggest that you double check your ignition timing. Also, make sure the distributor is advancing correctly.

Think it's lean? What do your spark plugs say?

Milkman · « **Reply #7 on:** May 21, 2007, 11:15:02 AM »

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what type of sender is it?

VDO brand. The type that goes where the #3 spark plug washer should be.

Milkman · « **Reply #8 on:** May 21, 2007, 11:17:21 AM »

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I would suggest that you double check your ignition timing. Also, make sure the distributor is advancing correctly.

Think it's lean? What do your spark plugs say?

Timing is set at 30 degress total advance at around 3000 RPM, advances nice & smooth too. At last check (about 3 weeks ago) the spark plugs were a nice tan color.

Everything seems ok, I think maybe I have a CHT Gauge that is not very acurate.

Trevor P · « **Reply #9 on:** May 21, 2007, 12:33:05 PM »

Do you have an infrared temp gun to try?
Point it at the bottom of cyls # 3 & 4, and compare it to the gauge to see if it's out of wack.

Milkman · « **Reply #10 on:** May 22, 2007, 07:15:36 PM »

I'll take an infared gun with me to FarFrumHome this weekend & see where the head temperatures are really at. Thanks for the tip!