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Topic: Timing and water temp

in Forum: C3 Engines

Timing and water temp (1/16)
 6/29/20 3:03pm
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


Joined: 6/29/2015
Posts: 50

I just had my L82 350 converted to a 383 stroker with roller cam and aluminum heads. The Compression ratio is now 10.4 to 1.

After about 20 minutes of street driving the water temp settles at about 225 degrees F which seems high to me. Also when I shut the car off and then try and start it, say 10 minutes later, it cranks and cranks before starting. I have total timing set at 35 degrees at 2500 rpm which produces about 4 degrees BTDC at idle 900 rpm. If the timing is off does it cause the hard starting and or high water temp.? If so what would be the recommended timing for this set up?  What water temperatures are some of you stroker owners running?

 

any help is appreciated.

 



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"Made to be run hard"
Simsbury, Ct.

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Re: Timing and water temp (2/16)
 6/29/20 4:36pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 631

My experience with timing is that too much advance will cause hard starting and retarded timing will cause it to run a little warmer. How did you arrive at the timing of 4 degrees at idle? I assume that's with the vacuum advance disconnected.



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1973 L-82 4 spd

Re: Timing and water temp (3/16)
 6/29/20 9:05pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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4 degrees btdc is definitely going to make it run hotter than it should. You need to bring the timing up to 8-9 at least. I would first suggest you contact the engine builder(if possible) and find out their recommendations on that. With your compression ratio, assuming it is accurate, you may need to use a higher octane fuel to run more timing advance....which will probably help with the hot start issue.

 



|UPDATED|6/29/2020 6:05:45 PM (AZT)|/UPDATED|


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Joel Adams
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Re: Timing and water temp (4/16)
 6/30/20 12:30am
NorskyLifetime Member
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Twin Lakes, CO - USA

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After shutting the car off is the carb HOT to the touch?  If so fuel in the bowl could be boiling producing vapor lock.  I had that hot start issue with "The Toy" and after putting a Mr Gasket "sandwich" set of spacers between the carb and the intake the carb never got more than warm to the touch.  Just a thought.



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Re: Timing and water temp (5/16)
 6/30/20 8:40am
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


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The engine builder recommended 8 BTDC initial and 35 @ 2500 rpm total timing. At the 8 initial ( were I'm getting the over heating and hard starting)the total timing was way advanced of the 35 degree total desired. If I set the total at the recommended 35 then the initial works out to 4 degrees.  I will take it for a test run today and see how that works out.  I'm nerves with the 4 degrees. I don't want to hurt the motor or valve train as I have too much money in this motor already.

This is with the a pugged vacuum line.



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"Made to be run hard"
Simsbury, Ct.

Re: Timing and water temp (6/16)
 6/30/20 10:50am
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 631

If the heat riser valve is still in the exhaust system, check to see if it's stuck closed.

If 8 degrees advance at idle gives you too much advance at higher RPMs then you might check to see if you can get a different set of centrifugal advance weights for the distributor.

Is it safe to assume that the radiator is clean and all of the seals are in place around it and on top of the radiator and also the fan is working properly?



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1973 L-82 4 spd

Re: Timing and water temp (7/16)
 6/30/20 11:21am
Dblancha79Gold Member
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Weatogue, CT - USA

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1979 C3 L82 383 cu in


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thanks, I'll check out the weights in the distributor. The aluminum radiator and duel electric fans are pretty new and fans are functioning properly. I have ceramic coated headers on it with no exhaust valve. Thanks for advise.



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"Made to be run hard"
Simsbury, Ct.

Re: Timing and water temp (8/16)
 6/30/20 3:25pm
F4Gary
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Grapevine, TX - USA

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Are you using ported vacuum or manifold vacuum for your advance?  I'm using manifold vacuum with an MSD distributor and I'm running about 16 degrees btdc. 

I also blocked off the exhaust crossover at the intake manifold gaskets.



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Re: Timing and water temp (9/16)
 6/30/20 9:42pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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Here's a couple of good threads on timing, vacuum, and carb adjustments. Both have excellent info from super knowledgeable folks.

Timing info 1

Timing info 2

 



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Joel Adams
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Re: Timing and water temp (10/16)
 6/30/20 10:19pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 631

Another potential timing problem is having too light of a spring on the distributor centrifugal advance weights. What can happen if it's too light is that it will start advancing at idle speeds which makes it very difficult to both set the idle and the timing.



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1973 L-82 4 spd

Re: Timing and water temp (11/16)
 7/8/20 12:27pm
nosal1
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Dunedin, FL - USA

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1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.


Joined: 3/21/2006
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Good afternoon,If the picture in this query is the 383 you are having issues with,let me make some suggestions.

I have built several 383 engine here in FL. (VETTER BOB in this forum) and in CA. and the first thing to address and that is you will have to go with a mechanical fan,preferably a 7 blade which they are hard to come by,but can do with a 6 blade.It can be installed with your present pulley with adapter, I had the same pulley on my '80 Vette..After you install the mechanical fan,then we can work on my next suggestion.

Connect a vacuum gauge to the vacuum port in the intake manifold behind the carb or the non metered port on carb,however the intake manifold port is more accurate..Depending the gross lift of your cam the vacuum will be about 9-12 inches optimum of mercury again depending on cam lift.Get the starting vac.. and record the inches and advance the distributor to increase the vacuum if it will,if not set at between 9 -12 inches at the highest you can go without advancing to far and if it does increase vacuum then it will increase idle speed, reduce idle speed as vac. increases to set at 850-950 rpm.If you are advanced to much you will have resistance( bucking and "rumping))  in spinning engine..If all goes well you can install your timing light to get actual timing by gun..

Good luck and success..                          nosal          Sal C

Re: Timing and water temp (12/16)
 7/11/20 8:24am
nosal1
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Dunedin, FL - USA

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1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.


Joined: 3/21/2006
Posts: 260

Good morning .I found a picture of my Vette with a 7 blade mechanical fan.I later installed a fan clutch and electric fan which comes on at 182 degrees..I take no chances as Vettes are notorious for running hot.  & blade fan and extension..

Sal C



|UPDATED|7/11/2020 5:24:26 AM (AZT)|/UPDATED|
Re: Timing and water temp (13/16)
 7/11/20 8:27am
nosal1
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Dunedin, FL - USA

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1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.


Joined: 3/21/2006
Posts: 260

 

Re: Timing and water temp (14/16)
 7/18/20 10:38am
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


Joined: 6/29/2015
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Thanks everyone for the suggestions. I am now able to get 35 degrees at 2500 rpm and 10 degrees advance at idle. A short test drive seemed to produce good results. My starter crapped out and I'm awaiting a new mini high torque 14:1 starter to give it a longer trial but I think I'm ok.



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"Made to be run hard"
Simsbury, Ct.

Re: Timing and water temp (15/16)
 7/18/20 1:31pm
F4Gary
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Grapevine, TX - USA

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1972 LT-1 convertible with factory air.


Joined: 8/26/2006
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Was it the distributor advance springs?



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Re: Timing and water temp (16/16)
 7/28/20 12:31pm
knotacare
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Newark, DE - USA

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1968 Conv, 454HO,500HP-600TQ, TKO-600,3:70 HD rear,hotrod air, custom paint & suspension,1973 Ruby Red,T-top, 383 Stroker, TK)-500,frame off restro, 1977 Yellow (1 of 51 ) L-48 4 spd, 99% original.


Joined: 7/26/2004
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Look into a advance timing light vs the digital one. The instructions are simple & you will get  the timing set perfectly especially on a modified engine.  Use some water wetter & use a 25% antifreeze 75% distled water setup.  If it still heats up you have other problems.



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