SBC cooling/ timing advance etc...

So I've got this purty Merc with a belly button crate engine.

Here is a chronology of how it runs. Now I spend 60% of my time going from light to light in traffic.

-First day, ran fine, But I was mostly moving.
-Second day, would give it gas, it would feel chocked out. I had to tow it a few blocks.
-So I put gas in the carb, started up. I decided to replace the fuel line from the mechanical fuel pump to fuel filter, the fuel filter, and the fuel line to the carb (which is 3/8). Done.
-Used a big clear filter. I can see it working.
-Day three, drove it a little, no problems.
-Day four, drove it about an hour. I can't honestly say what's normal for the engine yet from an operating standpoint. Usually it gets above 200F on my VDO gauge, and can get to 210-220 no problem. Today it was 96F out, super hot, and after getting stuck in slow traffic, temps creeped from 225 on the gauge to 235. Noticed my idle was dropping. No puking, thought maybe a little dieseling mighta been paranoid.
-Came home, sprayed carb cleaner around the vacuum line from the carb to HEI, idle drops. Sprayed around base of carb, idle drops. Tightened carb on the studs, was barely snug. Went to good and tight. Also bought new vacuum line, and used worm clamps on each end.

Setup:
-350 SBC, headers, Edelbrock with vacuum secondaries
-MSD HEI
-Electric puller fan
-Mechanical fuel pump
-Running mix of water and antifreeze

-Also notice that my idle in drive is too low. If I raise it up in park, then I have to have my idle in park up like at 1500.

----------
So for next steps, should I:
-Adjust carb first, or check timing first, or swap our thermostat first?

I'm leaning towards the stat only because I don't know what's in there. I'd prefer to run something like a 160 or 175 only because I'll change the oil pretty regular and I just don't want it to overheat.

Thoughts?

Thanks!

Some pics:







Old fuel line and filter, replaced it:

 

Sounds like a vacuum leak- high idle, cant idle in gear, hot. yup vacuum leak- you already found one- if it still does has issues then keep checking -intake, hoses, maybe bottom of intake (in the valley at the intake to head gasket)

dont run a stat colder than 180, unless you dont want the engine to last. If the cooling system can keep it at 160 then you'll oval the bores, and kill the bearings with acids/varnishes from water in the oil. If the system cant keep it at 160 then a 160 stat isn't helping is it.

factories put the correct stat for that engine in them (if one is provided)

rick

 

Pull the carb replace the gasket. If carb was loose for awhile it could have ruined gasket, and it could be old and cracked, brittle. A bad carb gasket will have a vacuum leak. check that vacuum tube on back of carb also. Check timing and replace the stat. All easy and cheap things. Mike

 

Do you have a heater? Did you bleed the heater core when you filled the radiator? There could be a pocket of air in your coolant system somewhere. Though I don't think this is your main problem, it may be contributing. Also, check the thermostat before you install it. Very easy. Just boil a pot of water, then drop it in and watch to see if it opens. Then remove it and see if it closes properly as it cools. I've had brand new ones that failed. Good luck.

 

#1 Advance Vacuum should be sourced from manifold vacuum which is the driver's side port, not the passenger side one you have it on in the pictures. Cut another longer hose and switch ports. That will give you enough advance most of the time to not run hot from retarded timing.

#2 (or #3)It appears you have the passenger side idle mixture screw all the way in. That and your claim of a 1500RPM idle makes me think you have the idle speed up so high it's trying to idle on the "mid range circuit" instead of the idle circuit. screw the mix screws in then back out 2-4 turns and lower the idle speed turn out the screw till changing the idle mix screws start having some effect on the idle. (repeat/fine tune #3)

#3 (or #2) Check timing with the vacuum advance disconnected and plugged and set to the advance to whatever the car the distributor is made for/came out of says it should be set to. could be anywhere from 11º to 0º depending on what "smog car" the dissy came from and whether it's still internally stock or not. (repeat/fine tune #2)

 

A belt driven mechanical fan ... would be my choice. And a good 180 thermostat. Run a shroud on the radiator and be done with it.



Mercury shown with a 460 Ford ... mechanical fan and a shroud.

 

Thanks guys will print out your suggestions and go through all the suggestions.

 

Do NOT put one of those open spacers on the car! It will bog like crazy. The Edelbrock manifolds all accept Edelbrock carbs without any adapter or spacer and should run just fine. Mine does. If you add a spacer, use a four-hole not an open one.
The carb gasket does sound likely, as does the detailed advice from DrJ.
It should idle and run like a new car when set up properly. You might still have a cooling problem (or not), but that is a separate issue from the poor idle and poor running.

Might want to check or replace the PCV valve, too, just to be sure it's not the source of a vacuum leak.

Personally, I'd check the timing too just because that is free and easy to fix if it's off. Probably should be around 10 degrees at low idle with advance plugged, at least as a ballpark number to start with.

How does it go down the road at speed?

 

Other than off-idle hesitation when I get going, it drives good.

I appreciate all the comments. Car was not driven for 3 years, so I'm fine with replacing hoses, pcv valves etc., just so I know that the stuff is new and that I did it.

So far:
-new battery
-new fuel line from pump to carb
-new fuel filter
-tightened carb nuts on the studs
-replaced vacuum line, clamped it too
-ran some lucas injector cleaner in the tank

 

Put a holley on it

 

I see you have steel braided lines, as I did. I had a problem similiar to yours and it ended up that a piece of rubber in the steel braided line came loose and it got stuck in the inlet of the carb, also a smaller piece ended up in the bowl. The larger piece would move around and cause rough idle or hesitation. My vehicle also sat for a while and I'm guessing that Ethenol ate the hose. Remember that the old gas line you have hanging around the garage might no be up to "Ethenol standards".

 

Well, actually, the edelbrock 'performer' series intakes are direct factory replacement and DO NOT work well with the edelbrock carb. Those intakes are for spread bore carbs and the edelbrock is a square bore. You can get a vacuum leak around the rear, what edelbrock reccommends is that you use thier plate #2732 to seal the carb to the intake. I prefer a heat shield, like mr gasket # 97 or 98 - they'll seal it off and cut down on the heat at the carb.

 

Get one of the after market large intake thermostats. I think Mr gasket is one brand? It allows more coolant to flow through it. 180 degrees is what I would recommend. If you are using a old radiator, you might what to consider having it boiled out and checked. The after market desert cooler or aluminum radiators are very good for higher performance V8 motors. The Edelbrock carbs can percolate if the motor is hot. Check for a thick cab to manifold gasket to help isolate it from the manifold.

 

I have faux braided lines so far. I replaced the fuel line to the carb. It was braided on the outside.

Hmmm hadn't looked into square bore vs. spread bore, I'll check that out.

I usually have to give it a little gas to start it, but it does not typically hard start. I'll go out on a limb and say the timing is potentially not super out of wack. But what sounds like a 500 rpm in park and drive is something I have to fix, and the cooling issue.

I'm thinking new aftermarket stat and some water wetter.

 

I think you have already been given pretty good advice, one thing I would add is to mark TDC on the balancer and then with the vac advance disconnected make sure the mechanical advance is actually advancing well past the timing mark when the rpms are up past 3000 or so 36* or so total would be about right.

 

Did you move the vacuum advance to the port on the drivers side as DrJ pointed out in his
post?

 

Well, actually, Edelbrock says you should use a plate on any spreadbore manifold EXCEPT their own Performer intake! Trust me, I read the fine print when I got my brand new Performer intake and carb because I'd never ever run an aftermarket manifold before and never bought a brand-new carb before.
The heat shield won't hurt, though, but if the gasket is leaking it's the gasket's fault not the manifold.

 

I've always run 160* thermostats and I've never had a problem with a block and cylinders. I'm not a fan of that carb either,Holleys are easier to work on and run better.
I'd check the thermostat and put a 160* in it,running a engine over 205* is asking for problems IMO. With the A/C,make sure you have enough airflow threw the condenser and the radiator.

 

It's been a while since I ordered from Summit, so it was fun to pick up the phone and get some stuff once it's way to me.

I ordered a Mr. Gasket 160 stat, carb insulting gasket, and some water wetter.

I will move the vacuum line to the other side as suggested for sure, I'll have to pick up another piece.

Michev, I'll look at my ac condenser setup, I haven't paid any attention to it. I see your point.

 

A 160 thermostat will open at around 160 and STAY OPEN ... so basically you have no thermostat after the engine warms up.

Go read this

http://www.chevelles.com/forums/showthread.php?t=281092

 

I get what you are saying (and linking). I just don't know what stat I have at all.

I've got an electric puller fan, but I guess I can also think about my water pump. I could also flush the radiator.

I think if I start looking at 7-8 things I might just drive it over to my buddy Pete at Pete's Auto Clinic on Bryn Mawr and let him help me avoid replacing good parts. ;(

 

I would agree that a 160 deg thermostat is a bad idea, I also think it is a bad idea to remove the thermostat and 'core it out' -like the guy on the Chevelle forum mentioned. I think the thermostat acts as a check valve to keep the water flowing in a loop, if it was 'cored out' I would worry about hot spots in the block and poor circulation.

 

You guys got me all riled up so I called Summit Racing back up, talked to Titus (great guy btw, had a '53 Chevy)...

So for now I will:
...Keep going with the 160 stat since I don't know what's in there
...Remove my newly purchased 16 psi radiator cap, and go to a 6 psi cap
...Add one bottle of water wetter.

When I drove the car prior to last time (when I had the old rad cap on), it did not get this hot, and the high psi cap per him will make it run hotter (which it did).

He also agreed with DrJ and the other poster in this thread that I needed to swap the vacuum reference to the driver's side, that the passenger side was for timing.

He theorized a bit about my park vs drive idle drop, and threw out the idea that maybe my motor has a little bit of cam in it and I need a looser converter. It used to lunge forward like an eager puppy on me so that's interesting. I really don't want to do a converter and that's probably a convo for after I make some serious progress on the cooling issue.

Thanks again all.

 

Most factory specs call for a 195* thermostat. A properly adjusted SBC tends to run cool. If it runs cool with a 160 then it will run better with a 195 and won't overheat. The problem with your setup is timing. You must run ported vacuum to the distributor. A retarded engine will run hot everytime.

 

If by ported advance you mean running the vacuum line to the driver's side port, I'm going to do that.

 

do not use mechanical fan with your AC/alt setup!!! the belts do not have enough "grip" on the water pump pully and the water pump fails to turn at proper speed, BTDT, it ate me an ass for months until I grabbed fan one day and could not tighten up belts enough to not let it slip, went with electric fan AND SHROUD, 180 high quality thermostat. the other issue also sounds like a vacuum leak as others have stated.

 

A high pressure cap will not make an engine run hotter. The higher pressure only raises the boiling point of the water. It reduces the hot spots that can create steam pockets and allowa the water to transfer heat. Steam will not transfer and makes the hot spot larger. Make sure that you have the proper water pump for your rotation. Some waterpumps are reverse rotation.

 

Thanks guys. Water pump is on my list for inspection.

No way I'm putting an mechanical fan on the car this year.

 

I'll have to disagree on this quote...You need full vacuum for the distributor

 

I've got 3-4 guys saying to switch to the driver's side outlet on the carb on the front, so that's my plan unless MSD wants to register and post.