#flex-dev Logs

Jan 19 2025

05:13 AM JT-Cave: morning
05:14 AM Tom_L: morning
05:25 AM Tom_L: i noticed some plugs in one of the pics.. were those from yours?
05:25 AM Tom_L: i'd run a compression test on that engine with the plugs out to check the valves condition
05:26 AM Tom_L: no backfire thru the carb.. intakes ok.. low compression then would be exhaust valve leakage
05:26 AM Tom_L: i'd look for between 140 - 160psi
05:28 AM Tom_L: more often than not it will be the exhaust valve on that test
05:29 AM Tom_L: low number could indicate that or ring blowby which can be further indicated by black wet plugs
05:34 AM JT-Cave: plugs in what photo?
08:44 AM Tom_L: https://www.corvetteforum.com/forums/c3-tech-performance/4898613-82-l83-runs-rough.html#&gid=1&pid=9
08:45 AM Tom_L: must not have been yours
08:46 AM Tom_L: https://cimg4.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1504/ac_r45xl_57bc68c2c910b91caf373a5b837618efbc8c5d7e.jpg
08:52 AM JT-Cave: those are all my photos except the black cap
08:58 AM Tom_L: i found those scrolling to the right after clicking on one of the pics
08:58 AM Tom_L: probably wasn't yours then
09:00 AM Tom_L: (2nd black cap) and if you keep scrolling there are more plug pics
09:00 AM Tom_L: the vise didn't look like something you'd own either :)
09:03 AM JT-Shop: I'm not seeing any plugs in my post
09:04 AM Tom_L: https://cimg1.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1504/looking_down_into_spark_plugs_1_cc8305f7bb735ac4035ad92363ce814768d50a7e.jpg
09:04 AM Tom_L: the one that shows #5 in the header
09:04 AM JT-Shop: where is that from?
09:04 AM Tom_L: your link :)
09:05 AM Tom_L: scroll down to the black cap in #5 post
09:05 AM Tom_L: click on the cap then scroll to the right
09:06 AM JT-Shop: those are just random photos
09:06 AM Tom_L: ok
09:06 AM JT-Shop: and I'm not seeing any of those photos when I click on the black cap
09:07 AM Tom_L: do you see the arrow to the right if you click on the cap?
09:08 AM Tom_L: from there, there are 5 plug pics
09:14 AM JT-Shop: yup I clicked on the arrow and it just goes around the photos in my post
09:15 AM Tom_L: in #5? odd
09:15 AM JT-Shop: 4 and 5
09:15 AM Tom_L: 4 doesn't do it here either
09:16 AM Tom_L: must be a forum thing i guess
09:16 AM JT-Shop: you have a magic browser!
09:17 AM Tom_L: how many miles are on your engine?
09:39 AM JT-Cave: 92k
09:40 AM Tom_L: shouldn't have any major issues yet then if it was serviced right
09:40 AM Tom_L: some of the patch jobs you've run across makes me wonder about that though
09:43 AM JT-Shop: actually I have no idea how many miles are on that engine... I've not verified that it's a numbers matching engine yet
09:44 AM Tom_L: does it have a 100k mile counter or just up to 99k?
09:44 AM Tom_L: iirc some of the older cars didn't go that high
09:45 AM Tom_L: iirc my S10 had 230k on it when the kid up the street bought it and it ran great still
09:48 AM C3-Shop: 99,999.9 max
09:50 AM Tom_L: so it's very likely rolled over once
09:51 AM C3-Shop: it would show up on the title if it has
09:56 AM Tom_L: ok
10:00 AM Tom_L: given that, a compression test will eliminate anything major
10:00 AM JT-Shop: well it ran fine on the way home so something has changed since I put the carb on
10:00 AM Tom_L: ok
10:02 AM Tom_L: that carb plate mentioned might help but it may be rich/lean on the top end
10:03 AM JT-Shop: the carb plate would not do anything IMHO
10:04 AM JT-Shop: the base of the carb and the gasket set the size
10:04 AM Tom_L: unlikely but i haven't messed with alot of intake changes
10:04 AM Tom_L: what carb was on it?
10:04 AM Tom_L: you could compare jet sizes
10:05 AM JT-Shop: a rebranded carter
10:07 AM Tom_L: check/change the fuel filter would be an easy check
10:07 AM Tom_L: i've seen some with bad hoses that plugged the filter
10:07 AM JT-Shop: it's not starving for gas for sure
10:07 AM Tom_L: rust in the tank etc
10:08 AM Tom_L: then maybe it's getting too much on the high end
10:09 AM Tom_L: put efi on it and you can play with that on your laptop :D
10:13 AM JT-Shop: I might have the vac advance connected to the wrong port but need to id the dist first
10:19 AM Tom_L: what's the factory say for the basic advance?
10:20 AM Tom_L: usually that's around 6-10 deg
10:21 AM Tom_L: For a 1982 Corvette, the recommended ignition timing is typically around 10 to 12 degrees before top dead center (BTDC), with the total timing (including mechanical advance) aiming for approximately 36 to 38 degrees at around 2,500 RPM for optimal power delivery
10:21 AM Tom_L: says google AI
10:22 AM JT-Cave: you have to look for an 81 not 82 because the 82 stock the ecm from the crossfire controls the advance
10:22 AM Tom_L: ok
10:23 AM Tom_L: full advance is the same
10:23 AM Tom_L: 36-38
10:23 AM JT-Cave: it's been basically turned back to an 81 with a carb and dist
10:24 AM Tom_L: 81's didn't come with vacuum advance.
10:24 AM Tom_L: https://www.corvetteforum.com/forums/c3-tech-performance/1881743-how-to-set-timing-on-an-81-a.html
10:31 AM JT-Shop: maybe 80 IDK
10:32 AM Tom_L: they're all gonna be similar on the full advance but the vacuum is better since it's not that advanced at idle
10:32 AM Tom_L: for a smoother bottom end
10:33 AM Tom_L: unless you have a crazy camshaft you seldom go beyond 35-40deg full advance
10:33 AM Tom_L: then if you do, it's not gonna idle smooth
10:34 AM JT-Shop: I'm thinking if the timing was set for full manifold vacuum and I plugged it into the ported vacuum that might be the issue but it's too cold to open the door and run the engine
10:34 AM Tom_L: that's why drag cars sound the way they do at the line
10:34 AM Tom_L: you need an exhaust tube :)
10:36 AM JT-Shop: https://www.corvetteforum.com/forums/c3-tech-performance/1430339-info-on-timing-long-post.html
10:36 AM JT-Shop: is that similar to a muffler bearing?
10:36 AM Tom_L: exhaust tube?
10:36 AM JT-Shop: yup
10:36 AM Tom_L: no shops use them in the cold weather
10:36 AM Tom_L: rubber tube put over the exhause ported outside
10:37 AM JT-Shop: ah I have some tubing but it's a tad small for the exhaust pipe
10:37 AM Tom_L: generally around 3" approx
10:39 AM Tom_L: that dist wouldn't have a centrifugal advance if it has a vacuum pot
10:39 AM Tom_L: inside the dist
10:39 AM Tom_L: spring loaded weights
10:40 AM Tom_L: that's some old old school stuff
10:43 AM Tom_L: if they didn't want the garage door cracked open they'd install a pluggable tube in the wall for the hose
10:49 AM JT-Shop: I've seen that before on garages
10:53 AM Tom_L: the stuff you use on your cyclone is probably too big
10:53 AM JT-Shop: stuff?
10:54 AM Tom_L: tubing for the dust collector
10:54 AM JT-Shop: oh too big for the exhaust
10:54 AM Tom_L: yeah
10:55 AM JT-Shop: stuff it with rags lol
10:55 AM Tom_L: you don't have to, just make sure it's well up on the exhaust and it will pull the fresh air in with it
10:56 AM Tom_L: depending on which way the wind blows that day :)
10:59 AM Tom_L: this ship we're going on doesn't burn diesel... they've converted to liquid natural gas
11:06 AM C3-Shop: the dist has both weights and vac advance
11:07 AM Tom_L: i wonder if you're getting too much advance then
11:07 AM Tom_L: the vacuum pot came with that dist though...
11:07 AM Tom_L: right?
11:08 AM Tom_L: figure out what the total advance is then and keep it in ^^ that range
11:08 AM Tom_L: but you'll have to test that with everything connected
11:08 AM Tom_L: since the weights rely on centrifugal force
11:10 AM Tom_L: i don't know how much advance each one gives you (weights and vacuum)
11:10 AM Tom_L: they may come in at different rpm too
11:12 AM Tom_L: the weights may give you half the total advanced and the vacuum the rest at different stages
11:15 AM Tom_L: that's where a timing light with the advance dial comes in handy since you can zero out the advance on it. the advance timing mark generally isn't marked
11:15 AM JT-Shop: yup I need a new timing light
11:18 AM C3-Shop: the thing is nothing prob changed since I put the carb on except the vacuum source for the adv
11:19 AM Tom_L: https://shop.snapon.com/product/Timing-Lights/Digital-Timing-Light-(Blue-Point)/EETL5568A
11:19 AM Tom_L: i'm sure that's a good one :)
11:20 AM Tom_L: mine isn't near that fancy
11:21 AM Tom_L: https://www.summitracing.com/parts/sum-g1059
11:21 AM Tom_L: that one is probably decent
11:23 AM Tom_L: you don't get the digital advance readout on that one
11:23 AM Tom_L: but it has the dial
11:25 AM C3-Shop: nice
11:31 AM Tom_L: you'll probably only use it once :)
11:39 AM JT-Shop: https://www.summitracing.com/parts/sum-850032
11:40 AM Tom_L: gonna change it all out ehh
11:40 AM Tom_L: ohm the wired before you hit 'pay'
11:40 AM Tom_L: wires
11:40 AM JT-Shop: the plug is glued to the cap so yup change it all out for new
11:41 AM JT-Shop: ohm what wire?
11:41 AM Tom_L: the plug wires
11:41 AM JT-Shop: what am I looking for?
11:42 AM Tom_L: https://www.youtube.com/watch?v=4_EFGAFxi1w
11:42 AM Tom_L: about halfway thru
11:51 AM Tom_L: that whole thing is actually pretty good
11:51 AM Tom_L: i've never done the water test
12:03 PM JT-Shop: https://www.corvetteforum.com/forums/c3-tech-performance/4898613-82-l83-runs-rough.html#post1608497784
12:03 PM JT-Shop: nap time
12:08 PM Tom_L: the black thing is the pickup sensor (hall?) i'm not sure
12:08 PM JT-Shop: I took it apart and it's just a connector
12:08 PM Tom_L: i'm sure included in the kit you're getting
12:09 PM JT-Shop: yup
12:09 PM JT-Shop: nap time
12:09 PM Tom_L: do check the plug wires if you're going to all this trouble though
12:09 PM Tom_L: lunch then nap
05:33 PM JT-Shop: https://www.corvetteforum.com/forums/c3-tech-performance/4898613-82-l83-runs-rough.html#post1608498302
05:37 PM Tom_L: getting the new kit?
05:39 PM xxcoder: anything look melty in car is never good
05:39 PM JT-Shop: yup and a new connectors for the power and tach and a proper accelerator cable stud for the carb
05:39 PM Tom_L: and a timing light..
05:39 PM JT-Shop: still looking for that
05:39 PM JT-Shop: I want to restab the dist so the #1 is in the right spot
05:40 PM Tom_L: would be nice to have one that shows advance but you'll only use it probably once
05:40 PM Tom_L: does it drive off the oil pump? i forget on those
05:40 PM JT-Shop: that's what I thought about the torque wrenches
05:40 PM Tom_L: heh
05:40 PM JT-Shop: drives off the cam
05:40 PM JT-Shop: er oil pump yea
05:40 PM Tom_L: most of your cars are efi with all electronics so setting timing on those is kinda moot
05:42 PM Tom_L: unless you plan to hop up the kabota or something :)
05:42 PM Tom_L: that plug wire in the pic doesn't look too old
05:44 PM Tom_L: they are likely ok
05:45 PM JT-Shop: https://www.amazon.com/INNOVA-5568-Pro-Timing-Light-Tool/dp/B000EVU8J8
05:47 PM Tom_L: should do the trick
05:49 PM Tom_L: iirc if you get the whole dist sometimes you have to rotate the oil pump with a screwdriver etc to align where the dist want's to be
05:49 PM JT-Shop: yup
05:49 PM Tom_L: since you're replacing one it shouldn't need to
05:49 PM JT-Shop: I plan on pulling the dist to get the plug wires in the correct place
05:50 PM JT-Shop: so I need the timing light to do that
05:50 PM JT-Shop: and new front tires on the C8 Friday
05:52 PM Tom_L: wonder what caused the plug to melt
05:57 PM Tom_L: i used to have a bent wrench for getting under the dist for the bolt
05:57 PM JT-Shop: I "think" I still have one
05:57 PM Tom_L: dunno if it's still in the box or not
06:05 PM * JT-Shop calls it a night