The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-21-2022, 06:44 PM   #1
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Frustrated overheating, timing issue?

Folks help me out - i spend tons of time reading this forum and others, I feel like I’ve tried everything, and it’s tough for me to ask for help but this trucks got me feeling like I’ve got more dollars than sense.. Pretty frustrated with my daily driver. It seems to overheat, stalls at idle, poor throttle response, gets harder to time the longer the truck sits with the fans running, seems to get really hot when running the timing procedure.

Truck: Bought this thing in september, it ran great in cold New York, not doing so well down here in 90 degree weather. 1971 350 2bm from an impala, 478 heads, performer aluminum intake, hooker headers with some cheap dual pipe exhaust job but no exhaust leaks, edelbrock 1406 600cfm. This thing sees some serious heat soak.

Cooling: I installed a cold case radiator with 12” electric fans, aluminum panels above the radiator and core support so the fans pull in more fresh air. It sees enough amps, but the shroud seems kinda tight - cold case claims that’s for better suction at idle. 180F thermostat. Temperature meter doesn’t present correctly - i put a lectric limited sender in it with no teflon tape, replaced the lead in the engine harness, have high heat wire loom around that wire under the headers, the sender itself has proper resistance and grounds well, cleaned the four posts on the temperature meter itself, but none of that changed the temp meter’s behavior. Thinking about replacing the temp meter and printed circuit board in the dash. Also thinking about putting the original shroud and clutch fan back on.

Fuel:Put a 2” phenolic spacer under the carb (2” might be a little much but don’t think that’s my problem.) . I rebuilt the carb, first with a cheap knockoff kit then with an edelbrock kit and set float to 7/16. Tuned AFM to highest steadiest vacuum with a vaccum guage - best i can get at most timing settings is 16-17. I’ve replaced the old fuel lines from the pump up to the carb, have a pressure gauge inline, fuel pump seems fine.

Air: oiled spectre air filter. Replaced header gaskets, brand new mufflers, no exhaust leaks.

Spark: I’ve spent the last few weeks messing with the ignition system. NGK spark plugs gapped to .45. MSD superconductor wires cut to fit, loomed really well (pretty proud of that), then messed with the timing. Had an old delco remy HEI in it, I replaced the broken vacuum can with an adjustable one and put it on the middle adjustment.i used the procedure in here to make sure my balancer’s TDC mark was accurate, it was only off .53 degrees but i marked it and use my new mark. Did all kinds if timing - wondering if I’m making an error here. So with the old HEI I put new moroso curve kit in it, the weights were not upside down and moved all the way in and out easily on the bench, i used the lightest springs. Vacuum removed and plugged, i turn the idle screw up until the timing light read 3000 rpm, 36 degrees total advance. Turned it back down to as low as possible, and initial advance only read 26 (10 degrees mechanical advance seemed wrong, seemed low), vacuum installed into manifold vacuum, brought it up to 53 (27vacuum advance, a little high). Troubleshooting by replacing parts is poor form, but this is where I started getting frustrated, so I installed a pertronix Ignitor II with their ignitor II coil. No ballast resistor, coil gets 12.4v, timed it to 36. Mechanical advance provides 24 degrees. When I get the timing to a good spot at total advance, I bring the idle screw back down to ~800 rpm, attach vacuum advance to manifold vacuum, then turn the idle back down to ~800 rpm.

As the truck gets hotter, it won’t idle unless I advance the timing more. Last weekend With the delco remy HEI I got it advanced as much as I could without pinging, drove the truck for ~4hrs that day, and it still seemed to be overheating past where I could advance the timing.

Doesn’t like to idle, sputters on throttle from idle (so i switched to ported advance to get home which seemed to work, but then really didn’t like to idle.

I’m thinking I have an overheating problem more than a timing problem.

I need to get the temperature meter fixed correctly. Probably just going to run a mechanical temp guage for now to be sure.

What jumps out to you guys? This is my first carbureted vehicle, i want to daily this thing in the georgia heat - can I get it running well enough for it to start up at 5am when it’s 50-60F and also after it’s hot in 95F heat of the afternoon.
69swb is offline   Reply With Quote
Old 05-21-2022, 07:17 PM   #2
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

Pics of the motor and rad/fan help.
geezer#99 is offline   Reply With Quote
Old 05-21-2022, 07:24 PM   #3
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,019
Re: Frustrated overheating, timing issue?

I sort of got into a loop like that. I ended up replacing the thermostat with a high-flow model after I noticed low flow in the radiator. Overheating at idle is poor air flow, overheating on the road is poor coolant flow. Mine was overheating in both regimes! I switched to a severe duty fan clutch and made my own fan shroud because the fan is too close to the radiator and wasn't coupling with the shroud. After all that is when I noticed the poor flow when hot with the cap off.
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is offline   Reply With Quote
Old 05-21-2022, 07:26 PM   #4
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Name:  53494041-714F-4F73-8584-568853A912B0.jpg
Views: 476
Size:  65.6 KB

Name:  C985AF5D-9B42-4282-9F87-16CFD4E3852F.jpg
Views: 543
Size:  67.7 KB
69swb is offline   Reply With Quote
Old 05-21-2022, 07:34 PM   #5
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by Steeveedee View Post
I sort of got into a loop like that. I ended up replacing the thermostat with a high-flow model after I noticed low flow in the radiator. Overheating at idle is poor air flow, overheating on the road is poor coolant flow. Mine was overheating in both regimes! I switched to a severe duty fan clutch and made my own fan shroud because the fan is too close to the radiator and wasn't coupling with the shroud. After all that is when I noticed the poor flow when hot with the cap off.
I might be having both problems, too. Cold case claims their 12” fans provide better cooling, but once I get this guage figured out I’m going to swap the fan clutch and shroud back in to compare. Maybe I hurt myself with their smaller option electric fans.

My fans kick on at 190, thermostat is just a 180 thermostat from autozone. Would a lower temp thermostat help me?

My brother advised that I get one of those funnel things to really make sure the rad is burped correctly, and troubleshoot the waterpump. He agrees that it sounds more like a heat than a tuning issue.
69swb is offline   Reply With Quote
Old 05-21-2022, 07:36 PM   #6
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

Check your bottom rad hose. Might be soft and collapsing.
While it might not help a bunch, your heater hoses are hooked up wrong. You can get trapped air bubbles in the coolant system. Should be intake to bottom of core, top of core to water pump or rad.
I’m not a fan (pun intended) of electric fans. I’d use a stock fan and shroud.

Stick with your 180 thermostat.
geezer#99 is offline   Reply With Quote
Old 05-21-2022, 07:50 PM   #7
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

I was just thinking about the bottom rad hose
69swb is offline   Reply With Quote
Old 05-21-2022, 08:04 PM   #8
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

Another thought about timing.
When checking it don’t assume the mechanical is all in at 3000 rpm. It might not be all in until 4000 rpm. Best to keep increasing rpm until advance stops climbing.
geezer#99 is offline   Reply With Quote
Old 05-21-2022, 08:07 PM   #9
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by geezer#99 View Post
Another thought about timing.
When checking it don’t assume the mechanical is all in at 3000 rpm. It might not be all in until 4000 rpm. Best to keep increasing rpm until advance stops climbing.
Yeah it’s all in at about 3200, I just kept it simple in the previous post. One interesting thing (i just put the all-in at 3000rpm springs in this brand new dist), turning the idle screw up it’s definitely all in by 3200, up to 3600 no change. At 3600, i wack the throttle lever - timing moves. Timing mark also isn’t super stable. Seems like timing chain to me.
69swb is offline   Reply With Quote
Old 05-21-2022, 08:32 PM   #10
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

Easy check for timing chain.
Pop cap off and rotate crank pulley both ways while watching the rotor. Shouldn’t move much.
geezer#99 is offline   Reply With Quote
Old 05-21-2022, 08:39 PM   #11
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,019
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by 69swb View Post
That engine's mighty sexy, right there!

I'd also replace that upper radiator flex hose. Those things can put a strain on the nipple at the tank. If it fits without a lot of finagling, it's probably OK.

Switching to a lower temp thermostat probably won't help.

As far as the gauge goes, mine was all over the place, so I changed to an aftermarket mechanical gauge (which I already had for a different vehicle which I sold); that cured some of the uncertainty.

If you're getting hot enough to vapor lock driving, the gauge isn't the issue.
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is offline   Reply With Quote
Old 05-21-2022, 08:47 PM   #12
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by Steeveedee View Post
That engine's mighty sexy, right there!

I'd also replace that upper radiator flex hose. Those things can put a strain on the nipple at the tank. If it fits without a lot of finagling, it's probably OK.

Switching to a lower temp thermostat probably won't help.

As far as the gauge goes, mine was all over the place, so I changed to an aftermarket mechanical gauge (which I already had for a different vehicle which I sold); that cured some of the uncertainty.

If you're getting hot enough to vapor lock driving, the gauge isn't the issue.
Thanks, it’s been quite some work to get it there.

I’ve got a fitted hose ready for it, but i’m just waiting for a free air gap to come then that hose and my fan sender can coexist.

Yeah it looks like burp real thoroughly, mech gauge, then probably put the fan clutch back on ( :/ bummer, the electric fans look so cool )
69swb is offline   Reply With Quote
Old 05-22-2022, 12:48 AM   #13
RichardJ
Registered User
 
Join Date: Apr 2010
Location: So Cal
Posts: 1,402
Re: Frustrated overheating, timing issue?

If your problem is overheating at idle, what do you care what the timing curve looks like at 3000 or 3600?

800 rpm is not idle rpm unless you have a big cam.

At 800 rpm the throttle blades are opening the transition slots and you really can't adjust the idle mixture screws.

At 800 rpm, most stock distributor curves have already begun to advance and you can't set your base timing. You mentioned softer advance springs which could be problematic, at least until you get your other problems sorted.


You need to get the idle down to 600-650 rpm.
For now, remove the vacuum advance hose and plug the carb port.
Check for vacuum leaks.
I'd put a radiator pressure tester on it and make sure the system holds pressure.


>>gets harder to time the longer the truck sits with the fans running, seems to get really hot when running the timing procedure.<<

What do you mean by "gets harder to time"? "timing procedure"? You turn the distributor until you reach the base timing that you want and then lock it down.

>>Tuned AFM to highest steadiest vacuum with a vaccum guage - best i can get at most timing settings is 16-17.<<

Is AFM supposed to be an acronym for fuel mixture? Does the "16-17" mean inHg or base timing. i can't tell for sure.
__________________
'67 GMC 2500, 292, 4spd, AC

Last edited by RichardJ; 05-22-2022 at 12:54 AM.
RichardJ is offline   Reply With Quote
Old 05-22-2022, 03:49 AM   #14
RustyPile
Registered User
 
RustyPile's Avatar
 
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,512
Re: Frustrated overheating, timing issue?

There are 12" fans and then there are 12" fans.. I have a Derale dual electric fan set-up on my aluminum radiator. The engine is a mild 454 BBC. I have it wired one relay for each fan. One fan is on a simple on-off switch and the other is on a temperature sensor set to come on at 200 degrees coolant temperature.. I live in East Texas and our temperatures are already hitting 100 degrees.. These days I start the engine, hit the fan switch and drive away.. Regardless of driving conditions, the coolant temperature settles in at 180 degrees and the second fan NEVER comes on. Here's a link to the Derale system.

https://www.summitracing.com/parts/der-16927

You have a severely restricted coolant flow if the engine overheats at highway speeds. Overheating while sitting still and idling means restricted air flow across the radiator, or those fans aren't spinning fast enough or just aren't capable of moving air.
RustyPile is online now   Reply With Quote
Old 05-22-2022, 09:25 AM   #15
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by RichardJ View Post
If your problem is overheating at idle, what do you care what the timing curve looks like at 3000 or 3600?

800 rpm is not idle rpm unless you have a big cam.

At 800 rpm the throttle blades are opening the transition slots and you really can't adjust the idle mixture screws.

At 800 rpm, most stock distributor curves have already begun to advance and you can't set your base timing. You mentioned softer advance springs which could be problematic, at least until you get your other problems sorted.


You need to get the idle down to 600-650 rpm.
For now, remove the vacuum advance hose and plug the carb port.
Check for vacuum leaks.
I'd put a radiator pressure tester on it and make sure the system holds pressure.


>>gets harder to time the longer the truck sits with the fans running, seems to get really hot when running the timing procedure.<<

What do you mean by "gets harder to time"? "timing procedure"? You turn the distributor until you reach the base timing that you want and then lock it down.

>>Tuned AFM to highest steadiest vacuum with a vaccum guage - best i can get at most timing settings is 16-17.<<

Is AFM supposed to be an acronym for fuel mixture? Does the "16-17" mean inHg or base timing. i can't tell for sure.
It’s the idle in park with an automatic trans. I’m in that ballpark in drive.

I time to total timing so that my car works. It’s 12 at idle, 24 mechanical advance, so 36 total. It’s a new distributor, So I wasn’t going to just set initial and drive off without testing all of the advance specs.

That’s a good point about the curve starting early - i’ll put in stiffer springs so centrifugal doesnt start till after 1000.

Because it’s overheating and idling all over the place. I’ll address my cooling issue.

inHG.
69swb is offline   Reply With Quote
Old 05-22-2022, 09:30 AM   #16
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by RustyPile View Post
There are 12" fans and then there are 12" fans.. I have a Derale dual electric fan set-up on my aluminum radiator. The engine is a mild 454 BBC. I have it wired one relay for each fan. One fan is on a simple on-off switch and the other is on a temperature sensor set to come on at 200 degrees coolant temperature.. I live in East Texas and our temperatures are already hitting 100 degrees.. These days I start the engine, hit the fan switch and drive away.. Regardless of driving conditions, the coolant temperature settles in at 180 degrees and the second fan NEVER comes on. Here's a link to the Derale system.

https://www.summitracing.com/parts/der-16927

You have a severely restricted coolant flow if the engine overheats at highway speeds. Overheating while sitting still and idling means restricted air flow across the radiator, or those fans aren't spinning fast enough or just aren't capable of moving air.

That’s one mean set of fans. About twice the CFM as mine. I’m gonna install mechanical temp guage, run a heat cycle with the electric fans, than switch back to shroud and fan clutch to compare. If the fan clutch works better, I’ll leave it for a while then maybe go to those stronger fans.

Gonna get a highflow 180F thermostat to replace my normal 180, check my water pump and lower hose.
69swb is offline   Reply With Quote
Old 05-22-2022, 11:29 AM   #17
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Name:  image.jpg
Views: 472
Size:  54.8 KB

Getting ready to get quite a bit done this afternoon

Install Mech guage, bench test and install higher flow thermostat, will be certain i’m burping thoroughly (just did uphill before this expensive funnel contraption), slap on the tighter curve springs while checking the timing chain then ensure I’m at correct initial timing, check the water pump weep hole, check the lower rad hose under load when hot. If it’s still getting hot I’ll swap to the original shroud and fan.
69swb is offline   Reply With Quote
Old 05-22-2022, 12:42 PM   #18
68 P.O.S.
Registered User
 
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,659
Re: Frustrated overheating, timing issue?

Straighten out your timing first or nothing else will be right. Sounds like you mostly have it handled at ~36 degrees total timing. Those Moroso HEI kits aren't really meant for a daily driver. Personally, I would put the stock weights and centerplate back in and put in springs that allow full advance between 2500-3000 rpm. Adjust your vac advance to provide 10 degrees of advance and then connect it to manifold vacuum (which helps with running cooler). Also, spark plug gap with HEI is 0.045.

Next I would move on to the carb. You rebuilt it so that's a good start. Edelbrock carbs can be finicky if not set up right. Set everything up to Edelbrock specs. Double check the float drop and rise. Fuel pressure must be restricted to no more than 6 psi (with a fuel regulator or a <6 psi fuel pump (Edelbrock recommends 5.5 psi)). Your accelerator pump should be in the middle position. These carbs need a spacer, or else they percolate fuel, so your spacer should work fine. Once carb is setup, you need to set the transfer slots in the main throttle bores to look like a square using the throttle adjustment screw. Once square, don't touch the throttle adjustment screw again. Then you can throw the carb on and give it a whirl. With the carb adjusted as above, the transfer slots squared,, and the vac advance connected to manifild vac, your idle should come out to 750 rpm. You'll also need a calibration kit to change jets, rods, and step-up springs. But you can do that after you get it running.

For your cooling, I would look at every part of the cooling system to make sure it's functioning correctly. Do a back flush of the radiator (heater core too) to get any possible clogs out. Correct the heater hose routing. Make sure your water pump and thermostat are functioning correctly.
__________________
72 C10 lwb fleetside -stock 350/350 combo
68 P.O.S. is offline   Reply With Quote
Old 05-22-2022, 02:01 PM   #19
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by 68 P.O.S. View Post
Straighten out your timing first or nothing else will be right. Sounds like you mostly have it handled at ~36 degrees total timing. Those Moroso HEI kits aren't really meant for a daily driver. Personally, I would put the stock weights and centerplate back in and put in springs that allow full advance between 2500-3000 rpm. Adjust your vac advance to provide 10 degrees of advance and then connect it to manifold vacuum (which helps with running cooler). Also, spark plug gap with HEI is 0.045.

Next I would move on to the carb. You rebuilt it so that's a good start. Edelbrock carbs can be finicky if not set up right. Set everything up to Edelbrock specs. Double check the float drop and rise. Fuel pressure must be restricted to no more than 6 psi (with a fuel regulator or a <6 psi fuel pump (Edelbrock recommends 5.5 psi)). Your accelerator pump should be in the middle position. These carbs need a spacer, or else they percolate fuel, so your spacer should work fine. Once carb is setup, you need to set the transfer slots in the main throttle bores to look like a square using the throttle adjustment screw. Once square, don't touch the throttle adjustment screw again. Then you can throw the carb on and give it a whirl. With the carb adjusted as above, the transfer slots squared,, and the vac advance connected to manifild vac, your idle should come out to 750 rpm. You'll also need a calibration kit to change jets, rods, and step-up springs. But you can do that after you get it running.

For your cooling, I would look at every part of the cooling system to make sure it's functioning correctly. Do a back flush of the radiator (heater core too) to get any possible clogs out. Correct the heater hose routing. Make sure your water pump and thermostat are functioning correctly.
I’ve moved on to a pertronix ignitor II since and the vacuum advance doesn’t seem to be adjustable, and unfortunately their vac cans aren’t the same size as my new adjustable can. I’ll report what vacuum advance it provides in a moment, just got home. I expect to be able to get 12 initial, 22 initial+vacuum, 36 initial+mechanical.

I have a calibration kit but did not replace anything yet - my metering rods are behaving correctly. Didn’t know about that “square” thing, I’ll remove and do that, thanks. Only actual changes I made other than replacement pieces/gaskets were the float rise. Guide I used showed a procedure using 7/16 drill bit to check total drop into the bowl - one was right on the money, the other was way off. i checked the floats for leaks and they were fine.

I’ll look up back flush procedure and check it out. About the heater hose routing - how come when I look up pictures of the routing all the pictures seem to match how mine is set up?

Thanks for the tips
69swb is offline   Reply With Quote
Old 05-22-2022, 06:41 PM   #20
68 P.O.S.
Registered User
 
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,659
Re: Frustrated overheating, timing issue?

Good deal on the pertronix

Good thing you have the cal kit. You can wait on changing rods and jets until you get the overheating under control. You can change step-up springs now. With your vac level you'll need the plain colored springs. Squaring the transfer slots is essential for proper carb operation.

For the heat, the intake manifold hose goes to the bottom heater core inlet, and the water pump return line goes to the upper heater core outlet.
__________________
72 C10 lwb fleetside -stock 350/350 combo
68 P.O.S. is offline   Reply With Quote
Old 05-22-2022, 08:12 PM   #21
rockyrivermark
Registered User
 
Join Date: Apr 2011
Location: Fairview Park, Ohio
Posts: 1,027
Re: Frustrated overheating, timing issue?

My 2 cents

1. I’ve seen more than one Brand new out do the box thermostats be bad.
2. Make sure electric fans are ran off a relay with heavy gauge wire going to the fan motors. If wiring is undersized fans won’t run at needed rpm
3. Head gasket failure could cause overheating. Make sure no water in oil or coming out tailpipe.
4. Back flush cooling system. Cleaner additive then flush. Prestone sells a nice kit with hose adapter and cleaner additive.
5. Get cheap IR gun to verify actual temp at thermostat hosing.
6. Both upper and lower rad hoses hot? Restriction?
__________________
My build page
http://67-72chevytrucks.com/vboard/s...d.php?t=764662
My cabinet building site
http://www.cbcabinets.com
rockyrivermark is offline   Reply With Quote
Old 05-22-2022, 09:38 PM   #22
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by rockyrivermark View Post
My 2 cents

1. I’ve seen more than one Brand new out do the box thermostats be bad.
2. Make sure electric fans are ran off a relay with heavy gauge wire going to the fan motors. If wiring is undersized fans won’t run at needed rpm
3. Head gasket failure could cause overheating. Make sure no water in oil or coming out tailpipe.
4. Back flush cooling system. Cleaner additive then flush. Prestone sells a nice kit with hose adapter and cleaner additive.
5. Get cheap IR gun to verify actual temp at thermostat hosing.
6. Both upper and lower rad hoses hot? Restriction?
Thanks
1. Replaced the thermostat with a high flow model and bench tested that new one today - it works. I had a cheap motorad normal 180 which I’ve not bench tested yet.
2. It’s in a relay and spent the extra $$ to get cold case’s wiring kit to make sure I had everything right (sure, made in china, yes the wires feel cheap), it has full power and correct amperage going to it. Currenty running both fans on on 190F sender
3. Yeah, I’m kinda worried about that - will see if it keeps overheating tomorrow after all of today’s work. I’ve had condensation coming out of the tailpipe at startup since I bought the truck. If it overheats tomorrow I’m going to get one of those fluid tests for exhaust gasses in the coolant.
4. I flushed it, new prestone coolant, used that funnel thing that screws into the rad. Filled the block first, then the rad, ran it with the funnel in the rad , whacking the throttle, until no more bubbles. I did get some steam coming off the top of the coolant in the funnel - that just because it’s not under pressure right?
5. I’m going to use an IR gun tmrw. Here’s a wrinkle: the fan sender is 190F, with the fans on (presumably engine coolant 190F), new bosch guage read 160F at the block. Only got up to 170F on the guage. Burped it really well with that radiator funnel contraption, and corrected the heater hose routing.
69swb is offline   Reply With Quote
Old 05-22-2022, 10:02 PM   #23
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

You mentioned proving tdc #1 is accurate.
What method did you use?
geezer#99 is offline   Reply With Quote
Old 05-22-2022, 10:19 PM   #24
69swb
Registered User
 
Join Date: Apr 2022
Location: Columbus GA
Posts: 34
Re: Frustrated overheating, timing issue?

Quote:
Originally Posted by geezer#99 View Post
You mentioned proving tdc #1 is accurate.
What method did you use?
Used a crank turning tool and a piston stop. compression stroke, marks at stop clockwise and counterclockwise, marked center of those two marks. Was only 1/32 (.53”) off of the mark on the balancer.
69swb is offline   Reply With Quote
Old 05-22-2022, 10:32 PM   #25
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Frustrated overheating, timing issue?

Another one!
Do you have a catch can/overflow coolant return system or just a vent line to the ground?
geezer#99 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:37 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com