running hot

['68OrangeSunshine]

Originally Posted by dave`12

First, I have taken radiator caps off of hot engines, and can do it safely. I hate to see an argument about this, but I do know that you have to be careful with advice. A shop teacher once told me a story about when he told someone that if you could turn the pulley on an alternator, the belt was too loose. Some fool tried it with the engine running and ended up with a mangled hand - so you have to be careful.

Anyway,


Thanx for all the replies. To address some of the points:

1. the radiator cap is new 16psi.
2. the coolant is new, 50-50 with distilled water
3. I guess a cheap mechanical temp gauge is not a bad idea, not sure how or where to hook it up? I really do think the engine is getting too hot, after years of tinkering on cars, I just think it is.
4. suprized on the timing advice. I looked it up, and I'm pretty sure it said 0 is the required timing. I did the timing with the vacuum to the distributer plugged. The vacuum is the only vacuum port on the engine, and it comes from the base of the carb. I will retime it.
5. @ swamp rat: I'm gonna reinstall the thermostat. I tend to agree that the alternator is most likely the sound I'm hearing. Bummer, one more thing to replace.

6. as far as the shroud, I have none, just a little thing on the very top to keep you from touching the fan. The fan appears stock (I have no idea) non-clutch, non-flex. It has a spacer and is about 4 inches from the radiator. I have what appears to be a 2 core radiator.

Should I get a shroud? Do you gentlemen think my fan is sufficient?

thanks again.

dave

L6s don't come with a fanshroud. If it's not OEM you don't need it. They may be critical for V8s but a six doesn't need one. There's a big black fingerguard over the fan but that's all.
A bigger radiator would help. Operating in southern Florida, you may want to think "tropical". I live in Tucson -- I have 4 tier cores on my trucks with V8s and a 3 tier on my 292 L6. The OEM L6 radiator was also about 3 inches shorter [narrower] than the V8 radiators. It's very hard to get an L6-specific radiator anymore. For about the same money, the V8 radiator fits and works great, once you move the brackets on top and bottom out to their new marks. Longer hoses may also be necessary, IDK.
I like the Stant "safety cap" it has a red lever so you can pull up the lever to release pressure, then twist open after the steam has blown off.

[Stocker]

Originally Posted by leftybass209

You have a 6 cyl, those never came with a fan shroud, only what you mentioned. There are lots of guys running that dinky little finger saver and their inlines don't overheat. While there's nothing wrong with a shroud and clutch fan and in fact, it's a great addition, it seems as though there's still something wrong. I'd hate to see you invest money in a band-aid first, rather than a solution. A shroud and clutch fan could possibly keep the engine cool enough to operate, but aren't necessarily the cause of the overheating issue, IF in fact, it's a mechanical fault and not a faulty old gauge.

Agreed on all points. I completely missed that it is a 6-cylinder. Guess I'm guilty of assuming SBC until someone yells at me to get my attention.

[RenoKeene]

You should also "BURP" the system. Jack up the right front of the truck so the radiator cap is at a high point. You can squeeze the bottom radiator hose to induce the bubbles to rise. Air will make its way up and out.
Sounds simple but it works.

[Mac's]

I agree with making sure the thermostat isn't reversed; I have done it.
I also have had an engine overheat because the timing was too retarded. I run my 307 at 12 degrees and it runs a lot cooler than the 2 degrees the manual says.

[Gromit]

Sorry to keep harping on ignition timing as your potential likely solution for running hot - but it is just a gut feeling.

You took the trouble to use distilled water - that says a lot in my book - and is a good sign among other things of what I observe as your sound instincts.

I found another good free source to help eliminate ignition timing as the source of your running hot issue - I still like our board member Bruce's thinking - but this is kind of a third opinion since you after all are kind of betting your motor on the decisions you end up making here and whose advice you listen to in attempting to correct the situation..

Here is a link to a Google scanned book: (at least previews are scanned; not the whole book)

https://books.google.com/books/about...d=8fsgc6GWR2wC

That link should take you to Google's preview of the 2004 3rd edition of the following book:

How to Build & Power Tune Distributor-Type Ignition Systems By Des Hammill

Google has extensive previews of that book so if you start reading on page 19 Google should let you look through the each consecutive page and it looks to me as if it will be helpful for your issue. So I'd suggest starting at page 19 and reading through at least about page 31..

One observation - there is no way around the fact that one way or another you do need to know exactly how many degrees of mechanical advance are built in to your exact distributor before you can set your initial timing accurately. For example if you just blindly set it at 11, 12, 13 BTDC and then spin your motor up to 3000 RPM; you are taking a big bet..

Sorry to keep talking about small blocks when you have a straight six - but after all there is a lot more info about ignition timing written out there about SBC 350's so I think it is still helpful to take the SBC 350 V8 ignition information into account and do your best to translate the theory or the principles into your inline six situation.. - but anyway just as an example; small block chevy distributors from the 60's and 70's eras have designed in mechanical advance ranging from 18 to 34 degrees (of crankshaft advance mechanical timing) built in; and so in my opinion I believe that you have to know what you have before you can set the initial timing on a points distributor..

One little tip I just learned is that many cam plates on the Delco-Remy Distributors had the number of designed-in mechanical degrees stamped into the Cam Plate... so that might be a good thing to check for starters..

Best of luck

['68OrangeSunshine]

Dave , what is your ignition set up? Points, Pertronix, or HEI? Timing is easy to set up on the Chevy L6. Stock one barrel carb?
Also if you get a mechanical water temp gauge, the sensor input threads into the drivers side of the head, replacing the electrical water temp sensor. A pipe of 1/8'' diamenter feeds thru the firewall to the gauge under the dash. You may need a gauge holder, but many temp gauges come with one.

[Aus69c20]

I don't think anyone has suggested it yet. But it could be as simple as a bad thermostat. In the past I've had two bad ones from brand new. Which caused the temp to rise very quickly.

Now I test thermostats in a pot of water on the stove. place the thermostat in a pot of water. heat the water and note when and if it opens with a temp gauge. A standard kitchen one should do.
Good luck

[dave`12]

Thanx Grommit. That stuff brings me back to my days in college, lots of reading and learning.

Just trying to get it to start easily and run fair and cool at the moment. Once I can get there, I will dig into that with a vengeance.

[dave`12]

@68 orange. As far as I can tell, everything is stock. It's a points distributer, 1 barrel Rochester (just purchased).

Anyone know how to set the dwell? I have no meter, and the cap has no window. I just want to get it close, does not have to be perfect at this point, that can come later with the excellent reading provided by grommit.

I would think the accelerator pump would be preset correct as I just bought the carb from summit. Anyone know how to adjust it to make sure?

thanx all

[dave`12]

played with the timing. seems to run a little cooler. Gauge gets 1/2 inch or so from the red and didn't go up for about 10 minutes. Anyone know the numbers? Where does yours sit? engine did seem a little cooler, I think the gauge works, but not at all sure it is completly accurate. Trying to avoid spending money on the mechanical for the moment.

[davepl]

The vacuum line going to the distributor should have no vacuum at idle; it's called "ported" vacuum and is a signal that represents part throttle load, which is where the vacuum advance can adds more advance.

At WOT, there's no vacuum. At idle, no vacuum. In between, ported vacuum.

Generally if it's below the level of the throttle blades, it's manifold vacuum. Above is usually ported, but that's not always the case.

[dave`12]

Thanx. So how can I use vacuum to help tune?

Originally Posted by davepl

The vacuum line going to the distributor should have no vacuum at idle; it's called "ported" vacuum and is a signal that represents part throttle load, which is where the vacuum advance can adds more advance.

At WOT, there's no vacuum. At idle, no vacuum. In between, ported vacuum.

Generally if it's below the level of the throttle blades, it's manifold vacuum. Above is usually ported, but that's not always the case.

[leftybass209]

Originally Posted by dave`12

Thanx. So how can I use vacuum to help tune?

Using vacuum, such as a vacuum gauge to tune, is done by connecting it to a full vacuum source. Then the carburetor is adjusted at idle, to produce maximum vacuum read on the gauge. This does work particularly well, but can only be done AFTER all other issues are sorted out, or it will just throw things off and you'll chase your tail.

Vacuum as in vacuum advance of a distributor, shouldn't NEED to be adjusted on a stock engine, as long as the components are in good condition. Custom applications and adding performance parts usually requires a vac advance to be tuned.

Sounds like timing was a factor in your engine running hot. You really should take it out and do some real-world driving and simulate some conditions to be sure it's running cooler.

[davepl]

Yep, like lefty says, no adjustment related to vacuum advance. You can get adjustable cans and lock out stock ones but generally only needed with significant engine modifications.

Get yourself a good initial advance (10 or 12 or whatever was decided) and see if its solved. If you go much more than that you'll likely need to lock out some vacuum advance, but that'd be indicative of the wrong solution, probably.

['68OrangeSunshine]

Originally Posted by dave`12

@68 orange. As far as I can tell, everything is stock. It's a points distributer, 1 barrel Rochester (just purchased).

Anyone know how to set the dwell? I have no meter, and the cap has no window. I just want to get it close, does not have to be perfect at this point, that can come later with the excellent reading provided by grommit.

I would think the accelerator pump would be preset correct as I just bought the carb from summit. Anyone know how to adjust it to make sure?

thanx all

L6 POINT-TRIGGER TIMING:
Get fresh set of Points and Condenser; remove old parts and replace. Bump rotor to point at #1 Cylinder, Timing Mark should be near timing tab off harmonic balancer and point to 0. Bump so points arm is on 6-sided cam and open most. Adjust gap with 2 screwdrivers** to .019 for new [.016 for used]. Plug Vac Advance temporarly.
Inspect cap and rotor. Reassemble if good. Start engine and after loosening distributor hold down bolt [9/16"] rotate distributor until groove in HB flashes at Zero mark on timing tab. You can advance from there if necessary.
To set Dwell you need a Dwell Meter*. Hook meter leads to Coil (+) and Ground, as specified in Meter instructions. Read on Six Cylinder scale. To make adjustments, shut off the engine, remove Dist. cap and rotor and use 2 screwdrivers to close or open the points gap, Closer gap = more degrees of dwell. [The option to adjust while running, with an allen key thru a 'window' is a V8-only thing.] Reset dwell gap and replace rotor and cap, start up and note readings again. It's still a trial and error process.
* With the popularity of HEI ignitions it's harder to find dwell meters. Check yard sales, swap meets, and used tool shops. I'll look up the p/n on my Sears Dwell/Tach/Voltmeter later. They may still have then in stock.
** The 2 Screwdrivers technique: One large flat blade on big screw in middle of pointset, one smaller flatblade in Gap hole to tweek points gap open or closed. When desired gap is RIGHT ON, lock down with big screwdriver.
OBTW Spark Plugs should be gapped to .035 for points.
Sorry I'm no help with the Monojet. I ditched mine in 1978 for a 4 Bbl Holley on an Offy intake.
Hope this helps.

[dave`12]

Thanx much, orange. I'm going to get the points and condenser, and try. I have an ugly (old looking) condenser also on the coil, is that part of the coil, or should I consider getting it as well?

and the scary part? the "condenser on the coil has a wire off it that goes NOWHERE!

I'm guessing it should go the the positive coil.

We may be getting to the bottom of my problems, I'm hoping that hooking that wire up makes a BIG difference.

[LONGHAIR]

Overheating, if it really is, generally comes down to "flow".
If it gets hot in traffic or in town at low speed.... it's and air flow problem. (lack of shroud, blocked fins, improper fan, etc.)
If it gets hot on the highway, is is a coolant flow problem.
(clogged radiator, crusty block, blocked/ in-operative thermostat, leak/low coolant, even low pressure in the system)
Timing can be a factor in either case, but that gets into a very detailed discussion.....

['68OrangeSunshine]

Originally Posted by dave`12

Thanx much, orange. I'm going to get the points and condenser, and try. I have an ugly (old looking) condenser also on the coil, is that part of the coil, or should I consider getting it as well?

and the scary part? the "condenser on the coil has a wire off it that goes NOWHERE!

I'm guessing it should go the the positive coil.

We may be getting to the bottom of my problems, I'm hoping that hooking that wire up makes a BIG difference.

Condensor on a coil sounds like an audio attenuator. It was used to keep ignition noise out of the stereo or [showing my age here] the Citizens Band radio. Delete it unless you plan on some ratchetjawing down the interstate. I doubt if it's necessary for simple ignition.

[hamjet]

Originally Posted by '68OrangeSunshine

Condensor on a coil sounds like an audio attenuator. It was used to keep ignition noise out of the stereo or [showing my age here] the Citizens Band radio. Delete it unless you plan on some ratchetjawing down the interstate. I doubt if it's necessary for simple ignition.

Also for AM if you don
t have resister plug wires...

['68OrangeSunshine]

Here's the p/n of my Sears Tach/Dwell/Voltmeter: 161.216500.
You might check Sears online for availability.

[dave`12]

Originally Posted by '68OrangeSunshine

Here's the p/n of my Sears Tach/Dwell/Voltmeter: 161.216500.
You might check Sears online for availability.

Thanx. It's too bad the multimeter I just bough does not do that. Trying not to spend too much money on getting it running, especially around the holidays. Do you think if I set the points correctly that I will be close enough for now? And I don't have a radio, but I already hooked up the wire, so I don't guess it will hurt.

p.s. That looks like my kind of truck in the pic
I really wanted one older than the 67 I ended up with, but could not find one without a ton of rust at my price.

['68OrangeSunshine]

Well, here are some pix of "Orange Sunshine" then:

As far as distributors, I had to revert to a point trigger set up when the Pertronix electronic ignition I had, burned out after only 7 Tucson summers.
And constant messing with the HEI on my '71 GMC's 350 has discouraged me from the HEI stuff.

[dave`12]

Love the stepsides. And it's a driver, so much the better.

['68OrangeSunshine]

Originally Posted by dave`12

Love the stepsides. And it's a driver, so much the better.

Thanks. Yeah, I've been driving it since I was 23.

I ran the numbers for the Dwell meter on Sears.com, but they don't have the whole unit availavble anymore. You can still buy replacement screws and pieces of the plastic case, but no instruction sheets either. Try thrift stores, swap meets, yard sales, Ebay.

['68OrangeSunshine]

Hey Dave:
Sears does sell a Sunpro Actron CP7605Dwell/Tach/Volt Meter,
Item# SPM6863027604
Model# B00062YUUS
$31.00