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Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 05:59PM

OK, I set the dwell to 32 (32.8 - 33) and the timing to 12 or 13 BTDC, and it pings like hell. Seems to ping less at higher rpm/speed, but pings really bad taking off at a light or stop sign. 91 octane gas with whatever CA puts in it, I think 10% ethanol.

It's fairly hot today (was about 95, now it's closer to 91). It almost seems like the engine is overheating, but it idles fine sitting still. RPM's around 850-900, and then I take it down the highway at 65-70 MPH and it runs just fine.

It's a 67 500 with a 95hp powerglide. If it's any consolation, the transmission is shifting perfectly. The car sat for several months with a transmission fluid/ can or trans-x blend in it. The trans-x seems to have restored the transmission back to like new condition (ok, probably not, but it shifts fine)

All cylinders have good compression. It seems to run really well. It just pings!
Is it getting ready to come apart at the seams?

Thanks,
Duane

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Re: Dwell and Timing and Pinging
Posted by: bill darcy ()
Date: September 05, 2011 06:36PM

Duane, you may want to check mechanical advance for missing,broken springs.A dial back timing light can be a real lifesaver when trying to diagnose ping issues.You can check advance at any rpm increments you like through the whole curve and see whats really going on.I usually set total timing to 33-34 degrees @ 3000 rpm and it has worked fine for me.I am at 5000ft elevation so your car may not be able to handle quite that much timing.If you havent allready checked you're damper now would be a good time to do so as they have been known to slip and then getting accurate timing is virtually impossible.Keep us posted.

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 05, 2011 06:55PM

Even though you "think" it still has stock 95 hp compression.... if it pings... use premium

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Dwell and Timing and Pinging
Posted by: RAV_AIR ()
Date: September 05, 2011 07:00PM

matt...91 IS premium.

something else is going on. like has been noted, check your damper, check your springs. What size jets in the carbs? What kind of spark plugs? maybe you need to dump some water or seafoam down the carb throats after you get it real hot...

"So where do they put the engines in these things?"
"They put em where they belong....in the rear."
1964 500 coupe
Topeka, KS
Searching for a complete 95 to rebuild. (changed my mind)
If this is still in my sig, I'm still looking.
Moderator

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 05, 2011 07:02PM

AHH... saw the 91 TEMP mentioned..forgot the 1st..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 07:38PM

The stuff about checking the damper and the springs is kind of out of my league. Maybe it's easy, I'm just not familiar with that.

I've never messed with the carbs. A local club member checked them for me and said they were balanced. He set the idle speed. I fear messing with carb adjustments. If it doesn't seem broken, I don't touch it. My lack of knowledge adjusting carbs keeps me in the area of "leave well enough alone".

I just saw in the shop manual that I should be plugging off the vacumm advance when I set the timing. I haven't been doing that. I'll go adjust with it blocked, and see if that makes a difference.

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Re: Dwell and Timing and Pinging
Posted by: LeeS ()
Date: September 05, 2011 08:30PM

I wonder what the compression ratio is and if this might be a simple case of carbon build-up...

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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 08:45PM

So I disconnected the vacuum advance, and the idle speed didn't change. I plugged the hose, and checked the timing again. It appears that the vacuum advance isn't doing anything, at least not at idle. But, with it hooked up, I can see the arm in the advance move when I increase the rpms. Seems to me the hose connected to the vacuum advance should be sucking air at idle. If it is, it's not much.

I drove the car about 6 miles just know. It's dark now, and around 75 degrees. While it did still ping, no where near as much as earlier today when it was in the 90's. I wish I could snap my fingers and have cyl head temp gauges in that instrument cluster that appear to be there just for decoration.

I got some carb cleaner that I willspray and check for vacuum leaks. I will also check the base of the carb to make sure it's not clogged with something. It should be creating enough suction that I should at least be able to feel it....right?

Isn't it fun trying to diagnose problems online? I think I might replace the vacuum advance unit on the distributor. I remember the guy that helped me adjust the carbs telling me to pound in the nipple with something to create more tension on the spring. Maybe I should just get a new one. Is that part accessible at NAPA, or is that a Corvair distributor part? (pun intended)

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Re: Dwell and Timing and Pinging
Posted by: lowandslow ()
Date: September 05, 2011 08:49PM

You said the car sat for several months. Any possibility of miserable mousies setting up housekeeping under the top shroud and blocking the airflow over the cylinders and heads?

I've used the Trans-X before and had success with it.

Patrick McGhee
1963 Spyder convertible
Weatherford, Texas

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 05, 2011 08:56PM

Duane, the VA only functions above idle opening of the carb...

And then it only advances the timing if the vacuum is high enough... it's for Economy....only functions when the engine isn't under moderate to heavy loading...

IE: cruising on the road at 40-70 mph...approx.!


You have been reading B-Nasty's topic? he's suffering overheating..

lots of good tips ...

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 08:57PM

When the car sat, it bumped my commuter car outside and it had an indoor garage spot. No mice around here, maybe just an occasional lizard. I cleaned the engine up pretty well abount a year ago, deflashed heads, and cleaned out any crap that was lingering in there. While it does seem to me that it's getting hot, I don't think it's anything caused by mice.

The car only has an idiot light for the temperature. Is there any way to check cyl head temp with a temporary solution? A dwell meter/timing light version of a temperature gauge? Just plug in into the hole on the cylindewr head? Am I dreaming?

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 05, 2011 09:18PM

[www.harborfreight.com]

If your heads are under 482F... should be!

[www.harborfreight.com]

Up to 962F

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Dwell and Timing and Pinging
Posted by: lgoodwin ()
Date: September 05, 2011 09:41PM

Duane, I don't recall you stating what the timing reading was with the hose from the vacuum advance to the right carburetor plugged off. The '68 shop manual says timing for 95hp/PG is 14 degrees BTDC--that is IF you have the correct distributor for that engine/trans combination SEE BELOW!

Your engine idle speed should be 600 RPM. If you are running higher, this will cause the vacuum advance to advance your timing at "idle".

From your description, it sounds like the mechanical advance is working, but you might want to remove the points plate and inspect the mechanical advance. I found that it COULD NOT advance on the distributor that came with the used '68 110 engine that I installed in place of the original '68 110.

While you have the distributor apart, check to see if you have the ORIGINAL DISTRIBUTOR model. I found a table in the SPECIFICATIONS section of the '68 shop manual that lists the "Ignition Distributor (Product Part No.)" for the 95hp/PG combo as "111031".

Lastly, check to see if the two damper doors at the rear of the car are opening up when the engine gets nice and hot. If they aren't opening up, this could be contributing to overheating. BTW, the "magic temp sensor" you were asking for DOES exist. It uses a laser to sense heat inside the engine from the outside.

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 09:45PM

Matt.....do you know anyone that has one of these infrared temp devices? Does it work? Seems like $20 well spent for me. If anything else, it will help eliminate overheating problems, as well as isolate them too.

Will it tell me the inside temp of meat on the grill as well? (not a requirement, just a bonus) Point it at your forehead and walla, it tells you if you've got a fever. Point it at what you think is a hot chick, should help determine just how hot she is. Lots of uses!

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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 05, 2011 09:58PM

Luke,

I saw the link from Matt on the temp device. For $19.99, I think I'll get one.

The damper doors on my car stay open all the time. The rods and bellows are in a box in the front of the car.

I'll check to make sure I have the correct distibutor. I took the vacuum line off the VA, and plugged the line. It made no difference. It didn't seem to have much suction, if any at all. I'm off tomorrow and I'm going to check to see if I can diagnose some of the things you guys have suggested this evening.

My car has the original hub caps and wheels on it. I like the way yours looks with the slotted mags. I've been thinking about getting either 14X7 or 15X7 Chevy Rally wheels with trim rings and the shallow center caps. What a difference it makes with the way it looks. (wheels, rings, caps, 4 tires - minimum of $400, that's the reason it still has hub caps, hard to justify for purely looks)

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 05, 2011 10:04PM

Duane.... larger wheel diameter and larger tires make a BIG difference in ride and handling

Go with 15" or 16".....13 /14's are getting hard to find..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Dwell and Timing and Pinging
Posted by: Chilly Willy ()
Date: September 06, 2011 07:53AM

Duane, What plugs are you running? I run the cooler plugs on a higher compression engine.also, have you tried to back off the timing a couple degrees?

Does it have the A.I.R. system on it ?

Did it run fine before you parked it ?

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Re: Dwell and Timing and Pinging
Posted by: corventure Dave ()
Date: September 06, 2011 12:12PM

Duane,

As a fellow Kalifornian... Lots of great advice given so far. Definately check the distributor number and mechanical advance springs under the points plate.
If everything checks out, you may be back to a timing issue.
First. Look at the crank pulley. In line with the timing mark is a couple scribe marks that are either side of the rubber center bushing of the crank pulley. If they are not all in alignment with the timing mark on the pully "found at the belt grove" then there is no way to set the timing correctly and the crank pulley will need replacement.I have seen many old and even bad new crank pullys that have slipped right there!
As for our Kalifornia fuel. It contains moon-beams and sun-flowers! Boutique gas it is called.... just for Kali. Back in the day Regular gas was around 90 octain. So our concocted Premium is not that great.
Here is what I do.
Balance the carburetors at idol as usual. Balance them again to get idol smooth and in spec's with the engine running and the transmission in "Drive". Chock the wneels and set the brake for this!
Timing... Fuels change with seasons, flowers blooming and what ever our governer is smoking! So I set the timing as advanced as possible without pinging. Drive testing is the way I do this. Upon hard accelleration one should not get a ping. Advance until you do... then retard the timing a little. I do a final check with the timing light, but I do not trust that printed setting with todays fuels.
Again this is after all vacuum leaks and other timing items have checked out.

Just passing this along.

Corventure Dave

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Re: Dwell and Timing and Pinging
Posted by: Duane1967 ()
Date: September 06, 2011 09:14PM

I thought I was on to something today. My heater is not hooked up, and the three inlet/outlet holes on the tin were blocked off with duct tape. The two on the bottom of the engine had melted through on the bottom corner. I thought the air that was getting out of those holes was causing the car to overheat. I replaced the duct tape with a supple aluminum tape, and went for a test drive.

It still pings. BUT, it only seems to ping after driving the car for a while. Taking off after the car sits for quite a while, it accelerates strong and doesn't ping at all. During the day today, it pinged quite a bit, but it was hotter outside, and I drove it much further. Within 5 miles after driving it tonight, the pinging came back, but no where near as bad. Then again, I didn't drive it longer to see if it got worse. Another time.

I don't think it has anything to do with timing or dwell. I think it's not cooling effectively, for some unknown reason. I will pull the cover on the oil cooler and look for some obstructions, and then I'll check the spark plug holes for bits of paper towel or something. All in all, it runs pretty darn good. But the pinging can't be good. If it's getting hot, it can't be good for anything that requires consistent lubrication.

I don't think the plugs are too hot, I don't think it has the wrong distributor, but I guess it could. I am the 2nd owner in the last 20 years, Who knows what the car/engine went through in the previous 25 years. The previous owner said he bought it from the original owner. He had it for 17 years, and only drove it 120 miles. Weird huh?

I'll report back on the obvious cooling restricting things. Maybe someone will enlighten me on blocking off the heater ducts. Maybe that isn't a good thing.

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Re: Dwell and Timing and Pinging
Posted by: MattNall ()
Date: September 06, 2011 09:28PM

Duane...as we've just told others this summer...


The ONLY outlet on the engine that is important to have the cose connected is the Fresh Air Hose to the heater...

Front right of your engine...a 3" hose..... AND you must make sure it is unbroken all the way to the heater connection!!

Many cap it off as it's really not needed by the heater.

And tell us again...

When did this pinging start? What had you done to it since the last time it drove well?

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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