All You CHT Gauge Drivers Report Here

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asiab3
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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Thu Feb 27, 2014 9:30 pm

Amskeptic wrote:
asiab3 wrote: I also want to put my stock exhaust back on and try all this.
I like to experiment, but I don't know if I could do that experiment in an evening after/before work.
I like reading the results of experiments . . . :happy1:
I'll acquire the exhaust from storage this weekend. Expect results in 5-10 business days.

Tonight I limited the total mechanical advance to 20*, down from 30* Now I idle at 7*btdc and max out at 27*. Pickup off idle doesn't stumble when cold cold anymore, (another reason to grab the old exhaust,) and the power band feels much closer to the 205Q DVDA I had for a few weeks. The freeway cruise was cut short by traffic, but temps didn't go above 400* until I really put my foot in it up a 4th gear grade.

I "allowed" a few more degrees of vacuum advance in from the adjustable can, taking me from about 4* to about 6*, and I didn't really see or feel a difference. Hard to say when every few miles gets you down to 3rd gear for some rubberneckers. More tests to come tomorrow and 300 miles over the weekend with plenty of time to stop and adjust. Hope the bus doesn't get mad that I'll be picking up parts for an upcoming engine build… :pirate:
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Tue Mar 04, 2014 12:16 am

asiab3 wrote:More tests to come tomorrow and 300 miles over the weekend with plenty of time to stop and adjust. Hope the bus doesn't get mad that I'll be picking up parts for an upcoming engine build… :pirate:
Sometimes these buses have a tricky way of making our lives better.

I drove three hours in the pouring rain to pick up some NOS single port heads for my build, and they ended up being the small-valve FI heads that I don't really want. So now I'm 100 miles from home, soaked, camping out at a cancelled swap meet. At that moment I had a thought- something like I've read in one of the past itinerary threads: "It's not raining 400 miles from here." Add to that my girlfriend's first birthday I wouldn't have been there for, and baseball spring training, so it's off to Phoenix we go.

I'm still seeing a gratuitous rise in CHTs when I push the pedal more than 75%. I have plenty of power up to there, and I was pulling the Indio grade at 55mph until I chickened out at 430*. The bus absolutely would have made the climb, but I didn't want to risk it. I took that as the sign that I could retard the timing more, and I did. took it from 28ish hose off to 25*btdc. Three degrees of vacuum advance dialed in both times. Temps didn't change very much, only a few degrees cooler. Had a wonderful time in Phoenix with good friends, and even got a bit of a sunburn. :sunny: Power felt the same, but I averaged 26 miles per gallon over three fills on the way home. After the third fill up I had to figure out the problem. One of my dual port intake boots has a tiny leak, when I hit it with carb cleaner the idle dropped down :( I rotated the boot and tightened the clamps down and kept the timing back at 25. CHTs stayed below 400 for rest of the desert, but the Tecate Divide saw some 430s when chugging along in 4th until it didn't want to maintain 50 and I downshifted. As soon as I descended into the San Diego area, temps dropped by about 25-30* all around. I could cruise at a real 65 on flat ground with temps not above 380. When I slowed to 60 for traffic and hills 370 was the norm. In the desert, those same conditions saw 410 and 400 respectively.

I'm back in San Diego now, so the stock exhaust comparison will have to wait. I'm curious if you have any thoughts on the differences in CHTs. Ambients don't affect THAT much, do they? Gas was always from Shell stations, always 87. Does air density/humidity make that much of a difference? Do I have a secret stroker motor? Did driving with my shirt off make the bus all hot and bothered? Are we stupid for driving 45-year-old cars across creation on a whim?

Did I mention the bus RAN great? If it wasn't for the gauge readings I'd say it was perfect.

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1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by Amskeptic » Tue Mar 04, 2014 12:22 pm

asiab3 wrote: NOS single port heads ended up being the small-valve FI heads that I don't really want.
. . . as in, they were actually dual-port heads?
asiab3 wrote: took it from 28ish hose off to 25*btdc.
Temps didn't change very much, only a few degrees cooler.
26 miles per gallon over three fills on the way home.
One of my dual port intake boots has a tiny leak,
CHTs stayed below 400 for rest of the desert, but the Tecate Divide saw some 430s

As soon as I descended into the San Diego area, temps not above 380.
any thoughts on the differences in CHTs. Ambients don't affect THAT much, do they?

Did I mention the bus RAN great? If it wasn't for the gauge readings I'd say it was perfect.
Do I guess correctly that you meant to write that you were looking for dual port heads?

If you are getting 26 mpg, I think you might have a lean condition that rears its head under hillclimb full-throttle. By the way, which boot had the leak?

Ambient temperature effects still elude me, I see the same reduction in CHTs coming down to the Pacific from the high deserts, but where I get thrown is seeing how readily these engines will throw a big CHT at you when it is only 43* outside. So, yes, I while expect a 20*+ hike in CHTs if the ambients are in the 90s or 100s, we sure don't seem to see a corresponding reduction when the temps drop into the 30s or 40s.

What are your current main jet/air correction jet numbers? Wait! I found them: 127.5 main/75air.
Try a 130 main and a 60 air correction jet, a 95 power circuit jet. How do your spark plug insulators look after all of this driving?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Wed Mar 05, 2014 10:15 am

Small valve EARLY heads. I don't why I said FI heads. They were stamped part 113 101 373B. Which is something like a 1300 head, no? I think I was brain-farting while thinking about Chloe's original valve blunder.

I am looking for NOS single port heads with the 35.5mm and 32mm valves. 211 101 373A or equivilent, (311.). Unless there is a trusty rebuilder that I don't know of. Everyone rebuilder I talk to wants to sell me dual port heads to go faster. That's not my priorty.


Last time I had the engine out I replaced both boots (even though they were fine, 8 months old) because it's a pain to do it engine in. I threw the boots on a shelf... Last month the right boot completely fell apart, 7 moths old. I put both used boots on and went on my way. This weekend the left boot was the one leaking. No visable cracks or holes. :scratch: Does it matter which side? The stock exhaust typically forces heat riser air from left to right, but my Vintage Speed exhaust is backwards- air goes right to left.


95 power circuit jet? I've never heard of that jet. Is it the same style jet as a main or idle? I can't find any reference to it shopping online. The local shop says "bring in yer old ones cause we dunno either..."

I'll check the plug insulators this afternoon.
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by Amskeptic » Wed Mar 05, 2014 11:16 am

asiab3 wrote: I am looking for NOS single port heads Everyone rebuilder I talk to wants to sell me dual port heads to go faster.
95 power circuit jet? I've never heard of that jet. Is it the same style jet as a main or idle?
I surmise that you want to retrofit back to singleport 1600 which would require a singleport intake manifold, which would require the smaller carburetor either a Solex 30 Pict2 or Pict 3, so what's the deal?

The power jet looks like a little round piece of brass stuck in the carburetor, it is not a screw-in jet.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Wed Mar 05, 2014 2:50 pm

Amskeptic wrote:
I surmise that you want to retrofit back to singleport 1600 which would require a singleport intake manifold, which would require the smaller carburetor either a Solex 30 Pict2 or Pict 3, so what's the deal?
Yes. I'm trying to build an engine from the ground up, so I KNOW what it going on back there. I'm still running on PO borrowed time. I'd like to complete it before the summer of 2015. No rush, I just want the good stuff.
The power jet looks like a little round piece of brass stuck in the carburetor, it is not a screw-in jet.
Colin
Does it have a number on here? I can't replace it if I can't find it :compress:

34pict3 exploded view:
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1969 bus, "Buddy."
145k miles with me.
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Re: All You CHT Gauge Drivers Report Here

Post by Amskeptic » Fri Mar 07, 2014 9:55 am

asiab3 wrote: Does it have a number on here? I can't replace it if I can't find it :compress:
34pict3 exploded view:
Ah, do a Google Search, there are so many variations . . .

Image


Image

Please note that the 34 Pict 3 uses drillings in the float chamber and that the "jet" might only be a pressed-in pot metal restriction and not the lovely brass deal of the PDSITs. . .
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Thu Mar 13, 2014 6:39 pm

I drilled out my power jets today....

...with GumOut :bootyshake:

I took the top off the carb and stuck the spray straw up into the passages that lead to the power jets. I sprayed the first one and the GumOut shot out of the jet just like it would out of the straw. The second one gurgled and had a lot of back pressure for half a second, then it sprayed freely like the first one.

So before attempting to switch anything else out, in the name of science I went for a drive. (Still timed 25*btdc from last week.) There's a series of hills on the 5 by my place that make a nice 15 mile loop, and routinely gets my head temp to 400+ on the first or second hill. By the fifth or sixth hill I could hit 430+ last week if I kept my foot in it. All of this used to be at 55-60mph. Today I really genuinely floored my bus for the first time. I could not get the head temps above 380*!! It held a true 65mph up the steepest hill at 375* floored. At the crest I saw 380* right before temps dropped down the back side. After that run I increased the timing back to 28* like I used to run, and there's about 2-3* of vacuum advance allowed when I plugged the hose back in. I did the 15 mile circuit again to make sure I wasn't seeing things. Floored at 68mph this time the DD gauge showed 390* at the peak. Ambients were 75*f at the local airport.

Needless to say, I'm really happy I'm able to just drive it again now. The "free" fix was an added bonus, and now I know what a power jet is too!! I'm not sure if it's a placebo thing- but cold takeoffs from a stop seem to be smoother now too. :scratch:

Thanks for all the help in this. I'll be much less embarrassed for your test drive in June now :)
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Thu Mar 13, 2014 9:31 pm

I'm going to leave that post above as a monument to my stupidity, and hopefully an educational reminder to future readers…

…Because I forgot to plug my electric choke wire back in after cleaning the power jets. So the engine was just suffocating itself to get those sweet CHTs. As soon as I plugged the wire back in and did my loop, 400* on the first hill, 410* on the second hill, etc. Maybe there wasn't a chunk in the jet after all. My head is spinning reading all kinds of sites about who calls what jet a "power" jet and an "auxiliary" jet, and how they might not even be jets after all.

I want to get to the bottom of these readings. And driving with the choke always shut doesn't sound like a fix to me.
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by Amskeptic » Fri Mar 14, 2014 8:16 am

asiab3 wrote:I'm going to leave that post above as a monument to my stupidity, and hopefully an educational reminder to future readers…

I forgot to plug my electric choke wire back in

I want to get to the bottom of these readings.
Stupidity? Naaaah. You have discovered that your engine wants more fuel. So . . . . . . . give it more fuel.

a) check float level - adjust to upper side of range
b) check main jet - go up one increment
c) check air correction - go down one increment
d) check upper gasket indexing - make sure power passages are clear
e) put the timing at the retarded side of the range
f) recheck power brake booster hose by a test drive with it blocked off - lower CHT readings?
make good notes so you don't chase your tail

You remember the agonizing trial and error testing of Chloe when I first bought it? I went to the end of my brain on that one.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Fri Mar 14, 2014 12:56 pm

Amskeptic wrote: Stupidity? Naaaah. You have discovered that your engine wants more fuel. So . . . . . . . give it more fuel.

a) check float level - adjust to upper side of range
This means removing one washer to raise the fuel level, correct?
b) check main jet - go up one increment
c) check air correction - go down one increment
Went from a 75 to a 60 two weeks ago and didn't see a difference.
d) check upper gasket indexing - make sure power passages are clear
That's originally why I took the carb top off yesterday. Spritzing the jets clear was a side thought.
e) put the timing at the retarded side of the range
That's the only way I can keep the temps decent. But I'm talking like, 20*btdc hose off. 24*-30* all show the same readings, just a little higher.
f) recheck power brake booster hose by a test drive with it blocked off - lower CHT readings?
'69- so not for me. Maybe when I'm older, since WW sells nice boosters made new.
make good notes so you don't chase your tail

You remember the agonizing trial and error testing of Chloe when I first bought it? I went to the end of my brain on that one.
Colin
Following Chloe's saga was keeping me on the edge of my seat. At least I discovered this site after that itinerary, so I could read the whole thing and not get nervous with anticipation of the next chapter. My valve adjustments are routinely mundane, one or two valves grow to .007 and the rest stay the same. I check every 2k miles. Maybe swivel foot adjusters will be installed in June......

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Re: All You CHT Gauge Drivers Report Here

Post by asiab3 » Sat Mar 15, 2014 11:00 pm

Last week:
127.5 main, 60 air, unknown power circuit.
Timed@ 25* hoses off: 390* cruise on flat ground, 60-65mph. 410* up hills at 55mph, could easily get it Too Hot up those hills.

This week:
Changed to 130 main.
Timing:
28* hoses off: 380* cruise on flat ground at a real 65mph, hills stay at 400* and don't easily get to 410* unless I really floor it, but then temps still can get dangerous.
25* hoses off: 370* cruise but did not exceed 395* from San Diego to Los Angeles this week, and only the steepest hill at a real 65mph showed 395*. Otherwise it was below 385* the whole trip.


Still wanting to make sure- If I take a washer out from under the needle valve, that will raise the fuel level, how will that affect mixture during operation?
1969 bus, "Buddy."
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Re: All You CHT Gauge Drivers Report Here

Post by energyturtle » Sun Mar 16, 2014 9:28 am

Stupidity? Naaaah. You have discovered that your engine wants more fuel. So . . . . . . . give it more fuel.
Colin
I talk to my bus everyday. When I listen and give it what it wants, it returns the favor. Today it is saying get a DD and report. The DD is on it's way. The first time we fired my new build, there I was in the AFM with my hand on the wiper with Colin saying, "Ask it what it wants". That has stuck in my brain like the words to Freebird. I will never forget it. I tried to hook up a VDO gauge, but I can't get the ring terminal over the spark plug threads. I also do not understand how the ring terminal is going to fit down in spark plug recess on the head at #3? Any thoughts are appreciated. :scratch:

Scottie

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Re: All You CHT Gauge Drivers Report Here

Post by Amskeptic » Sun Mar 16, 2014 12:27 pm

asiab3 wrote: Changed to 130 main.
Timing: 25* hoses off: 370* cruise but did not exceed 395* from San Diego to Los Angeles this week, and only the steepest hill at a real 65mph showed 395*. Otherwise it was below 385* the whole trip.

Still wanting to make sure- If I take a washer out from under the needle valve, that will raise the fuel level, how will that affect mixture during operation?
The above is "acceptable". Don't the perfect be the enemy of the good.

You do NOT just TAKE A WASHER out from under the needle valve. You CHECK the fuel level as per Bentley and REPLACE present washer with a small increment of thickness in whatever direction you want to go.

For example, if you reading is 17mm (float still in there) you want to shoot for 16mm (that is 1mm higher in all of the passages, a serious move towards richer).

Please note, since we are in a CHT thread, that distortions in the ring terminal can lead to insanely higher readings, because any hot gas leakage is horrendous. Check ring terminal for that stupid stretch where it has to bend to clear the spark plug well (are you reading this Energyturtle?). Sometimes you will see that the actual contact area is barely a tenth of a millimeter.
see diagram:

Image
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: All You CHT Gauge Drivers Report Here

Post by energyturtle » Sun Mar 16, 2014 1:39 pm

Check ring terminal for that stupid stretch where it has to bend to clear the spark plug well (are you reading this Energyturtle?). Sometimes you will see that the actual contact area is barely a tenth of a millimeter.
see diagram:
Colin
Got it. Mother nature is misbehaving today in TN. Tomorrow I will report my findings with the new build.

Scottie

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