360 Advice Needed - Autocross / Street Engine Build

-
It's ALIVE!!! :lol:

Just fired up last night a broke in the camshaft, that was a loud 20 mins in the garage!
Took a couple refills of the carb bowls before the fuel lines primed, but then she was good to go.

Engine runs smooth, with the oil gauge steady at 40psi idle up to 70psi at 2500rpm.

It got up to about 200°-210° during break in, I was spraying down the rad to keep it down. Hopefully the cooling system will keep up in traffic.

Anyone know which shrouds will work with the Spectra CU526 rad?
It looks like a replica of the 22" that came in these cars, and had the mounting tabs.

:thankyou:
 
Exhaust parts came in, hopefully get that done this weekend and should be a bit quieter!

Jegs 2.5" mandrel kit, no mufflers:
20180715_192914_resized.jpg

Jegs X-pipe kit: They do a nice job on welding these
20180715_192927_resized.jpg

Dynomax Turbos: (hopefully quiet enough!)
20180715_192947_resized.jpg
 
Not really much pre-made other than the set of mandrel bends when you start combining kits.
I've got about 8 hours into it so far cutting, expanding and bending pipe to make it work... :(

Should be onto the final fitment and painting for the exhaust this weekend.
Sure hope the sound from the X-pipe is worth it!
 
Here's the X-pipe and mufflers tucked up tight:
20180726_072808_resized.jpg


Dynomax Turbo style:
20180726_072734_resized.jpg


And the hidden tailpipes, painted black to blend in:
20180726_072709_resized.jpg


I'm going to run a piece of the old single 2" pipe out by the bumper, slant six style. ;)
20180726_072837_resized.jpg

(but will polish it up of course)
 
My '62 /6 has a 1-1/4' pipe... that would really fool 'em... not much for performance tho' LOL

So are you gonna leave either or both pipes open underneath? If so, make sure the fumes don't get sucked back into the passenger compartment. There is a reason to put the pipes out the side or back.
 
Went for the first drive tonight, but overheated after about 2 mins. Something ain't right...

Gonna borrow a infared gun from work tomorrow and check if the coolant is flowing as it should be. Upper hose was frm and scorching hot, lower felt hot to, but so did everything in the engine bay!

Temp gauge hit the 250 mark by the time I looped back home... :(
 
There's at least some, when I did the cam break in I had the rad cap off to get any air out, and you could see the water circulating.

It's a new 180° thermostat, and I boiled it to check that it's working. The cap is holding good pressure, and it's a new rad with just distilled water so far.

Will get some temp readings tonight on the:
- Upper & Lower hoses
- Radiator core
- Thermostat housing
- Headers
- Block

Hopefully that will make something clearly stand out...

20180729_175222_resized.jpg


Also will order the fan shroud from Mancini, haven't had any luck with used ones coming up in the last few months on FABO.

Looks like 2998 325 is the correct one.
 
There may be other issues but, be aware that you have 2 things that are going to make the coolant hotter:
- Higher CR... peak combustion temps go up a couple hundred degrees.
- AL heads... with their much better heat conduction, the coolant and rad are effectively 'coupled' more tightly to the combustion chamber temps.

As for radiant heat in the engine compartment, those AL heads will also couple the heat into the surrounding air a bit better. Ditto for headers, plus the heat they directly radiate out into the surroundings. Header wrap is partly for that purpose. (The other is to keep more heat in the exhaust and keep up exhaust velocity.)

So you have a bigger heat generator and better heat conduction and radiation all over.

Checking the coolant with a pressure gauge on the rad and looking for pulsing is another thing to do if this persists; the pulsing indicates combustion leakage past the head gasket. There are also chemical based detectors for that issue.
 
Last edited:
x2 on the leak detector which finds any CO in the H20
run a reference compression check and record for future use (and check for water)
 
Those headers sure run hot, even right after startup! Got a loaner of a FLIR camera from work, so was able to map out the engine bay.
FLIR0408.jpg


Also checked the timing, it 20° initial at idle, and total advance is 34° by around 2500rpm.
A/F ratio is currently 13.5:1 at idle and 12:1 under load.
Neither of these appear to be a source of excess heat.
(Will pull the plugs and compression test tomorrow after work)

So, for the cooling system:
Thermostat housing: 208°F (180° thermostat installed)
FLIR0411.jpg


Upper Hose: 170°F (rubber insulates)
FLIR0412.jpg


Lower Hose: 167°F
FLIR0414.jpg


Top of Rad Tank: 210°F
Bottom of Rad Tank: 201°F
FLIR0413.jpg


So based on all that, I strongly suspect that the water is flowing to the radiator, but in such low volume that it cannot cool the engine?

Failing water pump?
It's and old one, I probably should have installed a high flow one when rebuilding the engine. Didn't think about that until now!
 
Got a couple more mins tonight, so started compression testing. Plugs look good so far, just a bit of light brown.

Cyl. #1: 131psi
Cyl. #2: 130psi

DCR is about 8.2:1, so I think that's the right ballpark?
 
Kicker92 said:
Those headers sure run hot, even right after startup! Got a loaner of a FLIR camera from work, so was able to map out the engine bay.
View attachment 1715205212

Also checked the timing, it 20° initial at idle, and total advance is 34° by around 2500rpm.
A/F ratio is currently 13.5:1 at idle and 12:1 under load.
Neither of these appear to be a source of excess heat.
(Will pull the plugs and compression test tomorrow after work)

So, for the cooling system:
Thermostat housing: 208°F (180° thermostat installed)
View attachment 1715205213

Upper Hose: 170°F (rubber insulates)
View attachment 1715205214

Lower Hose: 167°F
View attachment 1715205216

Top of Rad Tank: 210°F
Bottom of Rad Tank: 201°F
View attachment 1715205215

So based on all that, I strongly suspect that the water is flowing to the radiator, but in such low volume that it cannot cool the engine?

Failing water pump?
It's and old one, I probably should have installed a high flow one when rebuilding the engine. Didn't think about that until now!
Click to expand...

That's a terrible temperature drop across the radiator.

You have a mechanical fan that was spinning when you were taking those measurements right? You should be looking at like a 30* drop in temps from the top to the bottom of the radiator. I'd suspect a plugged up radiator before a failing pump, but that's just me.
 
It's a brand new Spectra CU526 rad though, that should be clear and free flowing.
I agree though, the lower tank should be cooler than 9° from the upper tank.

It's the 5 blade mechanical fan, with the Hayden viscous clutch.
The clutch is spaced about 3/4" from the rad fins, and the fan sits about 1-1/2" back.
 
Kicker92 said:
It's a brand new Spectra CU526 rad though, that should be clear and free flowing.
I agree though, the lower tank should be cooler than 9° from the upper tank.

It's the 5 blade mechanical fan, with the Hayden viscous clutch.
The clutch is spaced about 3/4" from the rad fins, and the fan sits about 1-1/2" back.
Click to expand...

No shroud though? That would help a little, but, like I said that temperature drop is terrible. I'd expect a small improvement with a shroud, but not a 20* improvement.

Point that FLIR at the radiator, see if you have any cold or hot spots that would indicate uneven circulation. Just because it's new doesn't mean it's good.
 
The shroud is on order, should get here in about a week. It's a part I planned on adding anyways, keeps the fingers safer and will help that fan pull air through.

I didn't save the picture, but the FLIR of the radiator showed it a couple deg warmer in the corners away from the fan, but otherwise uniform.
The tanks were certainly warmer than the core section.

I'll drain a bunch of the water tonight and see what it looks like. Can't hurt to flush it out...
 
The fan may be spinning a bit but that does not mean it is locked by the clutch. I'd agree on the expected drop top to bottom in rad.

Cranking pressures are low for a DCR of 8.2. Ought to be 155-160 psi; you're near sea level.
 
Aha, that might be it! So I warmed it up tonight, and shut it down with the hood closed to get it heat soak.
The clutch fan still spun freely by hand.

What temp do these need to be at before locking up? The aluminum fins measured 160°F when I was spinning them.
 
I'd expect close to 200 F in the engine. This Hayden FAQ says the clutch actually engages around 170F:
Hayden - FAQs

So the air is just building up heat under the hood.
 
My 92 dak 318 with trailer tow had a service bulletin changing fan clutch from 185 with 7 blade 3" pitch fan to 195 with 9 blade 2 1/2 pitch fan and went to a 18 lb thermostat
3" fan was really loud
I'm looking at the GM 11 blade fan to test
all this is serpentine reverse rotation stuff
 
nm9stheham said:
This Hayden FAQ says the clutch actually engages around 170F:
Click to expand...

Thanks for the link! looks like it needs to be a bit hotter before I can ensure if it's working or not.

I pulled the lower hose off and ran some water from the garden hose through the rad. It seemed to have no problem with flow, so should be able to assume it's clear.

Have the shroud and a higher flow Mopar P5249559 water pump on the way for next week. Even if the pump is not an issue I'd rather replace the old jobber one from 22 years ago.

Might put the old 7-blade fixed fan on this weekend and see if the rad temp drops a bunch. That would narrow it down to an airflow issue.

Lots of other little projects in the meantime, finally fixed the loose rear-view mirror! It would swing around every time you gas, brake, or turn.
 
going to do the water pump you might want to do that old timing chain if you have not done so
let me know if it had nylon teeth
interested in your 7 blade test
do you have a valance/ spoiler
all the holes in the core support sealed up
 
You must log in or register to reply here.
-

Back
Top