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tuned up 65 365 hp car today

 
Old 06-03-2018, 03:45 PM
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hardhattg
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Default tuned up 65 365 hp car today

The spark plugs in my recently purchased 65 365 hp car were black and not clearing up by themselves , not oil but fuel black . so i decided to dive in and change the plugs today . All i could get locally were AC 45s and that was after two other stores that didn't carry the 45's at all .

a few hours later and my hands both look like i stuck them in the garbage disposal one at a time . the shielding is terrific fun to deal with , especially on the passenger side .

Also changed the cap , rotor , points and condenser etc.. the wires seemed like new so left them . after changing out just the distributor stuff the car would not start . so i took everything out one item at a time and kept putting old back in and trying to start car . finally took everything new out and put it back the way it was and still wouldn't start . watched some videos , read this forum and decided coil resistance may have been a little low . bought a new coil , no difference still wouldnt start . checked for spark with points blocked open , closed etc.. could not get spark to the plug wires . realizing it was probably a ground or other minor item i was missing i put all the new parts back in and it started instantly , still have no idea why . thats when i decided to change all the plugs .

set dwell @ 30 , full timing at 40/42 which is where it was yesterday when car was running good . gapped plugs at 35

now runs like crap . breaking up during even mild acceleration , just a little , bad bogging just revving in neutral , adjusted carb again and power valve . was fine before tune up .

forgot how much fun old cars can be . once i am finished with my transfusion i may try a slightly larger squirter for the carb hesitation .

anyone know what size squirter and jets a stock 365 with holley likes to run typically , think it has a 31 in there now , not sure what the jets are but probably gonna find out .

car would not rev past 5700 or so which is why i decided to tune it up anyway . even though it ran pretty good , that and the black plugs

never appreciated my 2017 corvette more .
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Old 06-03-2018, 04:02 PM
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Did you check the wire order on the cap? Double check that timing that seems wrong 36* sticks out as correct.
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Old 06-03-2018, 04:10 PM
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MikeM
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You might have been money ahead if you just tried to see why the plugs were black.
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Old 06-03-2018, 04:51 PM
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Default Tune up

swapping parts back and forth while watching videos how to do it without knowing how to trace / diagnose issues is not the best course of action. If you did that to your 2017 it would give you the same poor results.

its best to isolate a problem, like stated above, and slowly work that specific issue. Then move on to the next one.
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Old 06-03-2018, 05:19 PM
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It's funny how spoiled we have gotten with the cars built today, I bet that 2017 is one nice ride.

Without having the car to troubleshoot it's just guessing and maybe making more work for you, so here's my guess. If you have the dwell set, go back and set the timing at the initial setting of 10-12* BTDC and see how it runs. Set initial timing at a slow idle speed with the vacuum advance disconnected and hose plugged then reconnect the vacuum advance and set the idle speed correct and adjust the A/F emulsion screws on the primary metering block. You want the emulsion screws about the same turns out on each side.

The 2818 Holley pump squirter size is .025 so if you have .031 there should be plenty of fuel IMO.

Last edited by tbarb; 06-03-2018 at 05:21 PM.
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Old 06-03-2018, 06:26 PM
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Originally Posted by Nowhere Man View Post
Did you check the wire order on the cap? Double check that timing that seems wrong 36* sticks out as correct.

i initially did set timing at total 36 and was advised by reputable corvette shop that it would run better at 42
total timing and it does / did.
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Old 06-03-2018, 06:31 PM
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Originally Posted by Boyan View Post
swapping parts back and forth while watching videos how to do it without knowing how to trace / diagnose issues is not the best course of action. If you did that to your 2017 it would give you the same poor results.

its best to isolate a problem, like stated above, and slowly work that specific issue. Then move on to the next one.

I just purchased the car and Carb floats were intially way out of adjustment and sticking . Adjusted those and car was running ok but plugs Never cleared by themselves like fuel fouled plugs often due.

Its no longer tyoical to change all ignition components at once ? Always thought it was incorrect to change just some
igntion items. I have always changed Cap , points , rotor and plugs at same time when tuning these older cars up.
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Old 06-03-2018, 06:37 PM
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Originally Posted by tbarb View Post
It's funny how spoiled we have gotten with the cars built today, I bet that 2017 is one nice ride.

Without having the car to troubleshoot it's just guessing and maybe making more work for you, so here's my guess. If you have the dwell set, go back and set the timing at the initial setting of 10-12* BTDC and see how it runs. Set initial timing at a slow idle speed with the vacuum advance disconnected and hose plugged then reconnect the vacuum advance and set the idle speed correct and adjust the A/F emulsion screws on the primary metering block. You want the emulsion screws about the same turns out on each side.

The 2818 Holley pump squirter size is .025 so if you have .031 there should be plenty of fuel IMO.

thanks for advice. I did actually set the initial timing at 12/14 degrees first but it does run better with all timing in at 40/42 degrees with no preignition. I did use a vacuum gage to adjust the a/f screws .

I am am hoping I donít have to chnage these plugs again. There was at least a couple forum members that had bad experiences with the r 45s extended tip.

Will let hands heel a bit and see how these plugs are burning.
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Old 06-03-2018, 06:41 PM
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Originally Posted by hardhattg View Post



I just purchased the car and Carb floats were intially way out of adjustment and sticking . Adjusted those and car was running ok but plugs Never cleared by themselves like fuel fouled plugs often due.

Its no longer tyoical to change all ignition components at once ? Always thought it was incorrect to change just some
igntion items. I have always changed Cap , points , rotor and plugs at same time when tuning these older cars up.
Got to wonder how old, or how long fuel has been in the tank, these are not the "good old days" when it comes to this crap gas......just a thought!
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Old 06-03-2018, 07:28 PM
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Sounds silly but it's amazingly easy to accidentally swap plug wires when replacing the plugs, especially when you're hemorrhaging from multiple lacerations and not thinking straight

Also been known to happen that plug wires aren't snug, either at the plugs or the dist/coil.

All wiring that was touched during the operation should be double checked if it runs worse after a tune-up than before. I seriously doubt the spark plugs themselves are the culprit.

Last edited by SW Vette; 06-03-2018 at 07:32 PM.
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Old 06-03-2018, 07:33 PM
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Originally Posted by SW Vette View Post
Sounds silly but it's amazinly easy to accidentally swap plug wires when replacing the plugs, especially when you're hemorrhaging from multiple lacerations and not thinking straight

Also been known to happen that plug wires aren't snug, either at the plugs or the coil.

All wiring that was touched during the operation should be double checked if it runs worse after a tune-up than before. I seriously doubt the spark plugs themsekves are the culprit.
also if the prior owner installed the distributor incorrect and the firing order is one tower off and you install the plug wires starting on the correct tower it wont run very well
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Old 06-03-2018, 09:31 PM
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Originally Posted by hardhattg View Post



thanks for advice. I did actually set the initial timing at 12/14 degrees first but it does run better with all timing in at 40/42 degrees with no preignition. I did use a vacuum gage to adjust the a/f screws .

I am am hoping I donít have to chnage these plugs again. There was at least a couple forum members that had bad experiences with the r 45s extended tip.

Will let hands heel a bit and see how these plugs are burning.
I may have missed the comment, but make sure the vacuum advance is disconnected and plugged at the manifold before tuning initial or total timing advance.

I recommend 38 degrees total timing with no vacuum advance, and then back down the rpm to idle and measure the initial advance. The initial advance at ~800 rpm should be around 12 degrees, with a rough idle but responsive to air/fuel screw changes.

Fuel fouled plugs are not usually black. If you have been washing the cylinder walls with high float levels dumping fuel into the engine you may have lost ring seal. The remedy is to get the float level right, just below the bump test level, and get the engine to run smooth at rpm so you can make some WOT runs with the engine warm to seat the rings. You need the rings to seat to get the air/fuel mix at idle. You need to start there, so drive hard and get it sealed.
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Old 06-04-2018, 06:46 AM
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Originally Posted by 63 340HP View Post
I may have missed the comment, but make sure the vacuum advance is disconnected and plugged at the manifold before tuning initial or total timing advance.

I recommend 38 degrees total timing with no vacuum advance, and then back down the rpm to idle and measure the initial advance. The initial advance at ~800 rpm should be around 12 degrees, with a rough idle but responsive to air/fuel screw changes.

Fuel fouled plugs are not usually black. If you have been washing the cylinder walls with high float levels dumping fuel into the engine you may have lost ring seal. The remedy is to get the float level right, just below the bump test level, and get the engine to run smooth at rpm so you can make some WOT runs with the engine warm to seat the rings. You need the rings to seat to get the air/fuel mix at idle. You need to start there, so drive hard and get it sealed.

thanks this sound like good advice. I believe the float levels are correct now but they werenít when purchased car from auction . I did of course have vacuum blocked at manifold when setting timing . Will back it down a few degrees .

Thanks again all
imput is appreciated
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Old 06-04-2018, 08:22 AM
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When i tuned my 365hp how ever many years back , I remember something about setting the idle @750rpm, and adjusting the air mix to maximize the vacuum at that idle, I believe I achieved 12psi vacuum at 750rpm. Car ran excellent, after going thru the carb, distributor, plugs wires, points, ect... Maybe someone with more knowledge on that process could chime in as I am no expert on this.

Last edited by Rob_64-365; 06-04-2018 at 08:23 AM.
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Old 06-04-2018, 09:00 AM
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Originally Posted by Rob_64-365 View Post
When i tuned my 365hp how ever many years back , I remember something about setting the idle @750rpm, and adjusting the air mix to maximize the vacuum at that idle, I believe I achieved 12psi vacuum at 750rpm. Car ran excellent, after going thru the carb, distributor, plugs wires, points, ect... Maybe someone with more knowledge on that process could chime in as I am no expert on this.

12 in-hg is high for a 30-30 cam. Either your gauge is inaccurate, the lash is too wide, or the engine is using an LT1 cam.

30-30 cam lashed to spec should see about 8 - 9 in-hg @ 750 rpm.
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Old 06-04-2018, 10:16 AM
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I couldn't remember the vacuum numbers, I remember it being spot on to what the forum posts said it should be, it was a while back, I was thinking it was 8 or 12, but point being, that we had set the mixture per the vacuum gauge.
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