Chris, thank you for the shoutout and the kind words. Your video will educate the early c4 owners of the different spark plugs. A bit of history on the L98 cylinder heads. 1985 used the iron cylinder heads and was supposed to be the only year with the iron cylinder heads. 1986 started production with the aluminum heads and the heads started cracking around the lower head bolt bosses. These heads were replaced under warranty and there may have been a service campaign to get the heads replaced. The legend is that all '86 convertibles are equipped with aluminum heads and all coupes after convertible introduction also have the aluminum heads.
I agree with Nash, we've ALL done something with ours "toys" that we look back on with just a touch of disgust, embarrassment, regret, thankful to have survived, etc... Thanks for your willingness to share all your Corvette experiences with us.
Hi Chris, my name is Alessandro and I live in Italy. I recently bought my Corvette C4 and I found all your videos very interesting. I wanted to thank you and wish you good work for the future. Thank you, see you soon
Chris, I glad it wasn’t the other way around. ( long reach plugs in a standard reach head).Could’ve been a costly mistake. Your videos are great and inspire other car enthusiasts to undertake these projects. Keep it Up!
the longer thread also provides more force to keep the plug in tight and aluminum being softer it protects the threads, anyway the pressure is like 1500psi or a bit higher so I guess they can hold at least for a while. The other reason is they get better cooling from the head.
with those short plugs the spark begins inside the cavity and should mean slightly longer flame propagation so it would need slightly more advance. Mechanically it puts twice as much stress on the aluminum threads and these engines are also pretty high in torque. there is also less heat dissipation through the treads but I don’t think it’s a problem
Bought a lo mileage 96 LT4. Decided to install fresh plugs and wires. Went to the trouble and expense to source correct GM plugs and red wires. When installing ,I found the #8 plug loose. Dodged a bullet there. She runs like a beast to be stock. Use only AC/Delco parts in your C4 when possible.
Great info! It's amazing what some of our co-corvette owners know and notice things that slip by the rest of others. It is great that we can pass info via this forum. 👍 Can't wait to hear the new c4 exhaust!!!
I bought my '88 in '89. After about 5 years, it was going through alternators almost yearly. I finally figured out what was going on. The alternator would fail on a hot SoCal day while stuck in traffic with the AC on MAX. I was getting Pep Boys "Lifetime" warranty alternators. They replaced each one without any explanation why they were failing so much. I actually read somewhere online how Pep Boys (and others) puts a very cheap Chinese diode set in the alternators. It would work ok in light or moderate loads. But, in a heavy load situation such as stop and go driving on a hot summer day, with the AC on high, one or more of the diodes would fail. So, I decided to cut my losses and NOT get my next alternator at Pep Boys. I bought a high amperage ($$$) alternator about 20 years ago and it is still working.
Great job Chris. You right none of us know everything about everything. I've found it to be a good practice to lay out the old parts and new parts and inspect them carefully. If they are visibly not the same then find out why. A big thumbs up to your viewer for catching that on the video. I wouldn't have ever noticed.
I actually did the opposite and put the long reach plugs for aluminum heads into my iron heads.. the old plugs were long reach too, good news is it never hit pistons or did anything horrible. Got the correct plugs back in it now.
Heres a tip from an old racer, If you have an engine that uses oil and fouls up plugs, like an old fork lift or farm implement etc, use a short reach plug in the thing and the plugs wont oil up, my old fork is running proof of that. As for your little gaff ? WELL this happens from time to time, after all we are ALL human. Keep up the good work fella and i will keep watching........ Eddie C4 Australia.
I actually caught the shop I went to make this mistake but have since replaced the plugs with the proper .035 gapped (with the gasket) plugs. Also torqued to 12ft/lbs. Anyways, nice video!
At 7:11 the belt was on the side of the pulley..!😎 Ive got an 89 That I saved from the stripper and ive got the engine done and back in the car but it is running extra rich. No codes stored..
I just installed mine yesterday and realized they are the wrong ones too. I’m on my way to buy the correct ones and waiting for the cables to come in. Double work. I didn’t run the car.
Great videos. I noticed that your serpentine belt wasn't on when you said let's go start the car. I cringed seeing that. I'm sure the belt seated itself when you started the car, but still was scary to see. Keep up the great videos. C5 50th anniversary convertible owner myself.
I spotted that too. Depending on rotation, the belt will derail and shred itself. I speak from experience with my '88 C4. Like you, I also have a C5 50th Anniversary.
Hey everyone! I just wanted this video, thank you guys for the information! I just picked up an 86 c4 the other week, it’s due for some spark plugs. I’m confused after this video about which spark plugs to buy. Im unsure if it’s a late 86 or early.
If you are getting low voltage off of your alternator, that's a common problem. It's because you don't have the factory radio in. I know, it sounds ridiculous, but I've gone through 4 alternators until a Corvette expert saw it. It usually happens when the car has heated up and the cooling fan kicks in. The best thing to do is find a factory replacement or redo the entire system. I was told that each speaker has it's own amplifier, therefore not any radio can work. However, there are some that make alternate radios. But you gotta look into that.
@ Harry Ballzak So you are saying the car can show low voltage when the cooling fan cranks on AND the wrong radio is on? Does it do it with radio off? Do you believe it is because the wrong radio draws too much AMPS? Just curious...not trying be ugly here. Thx.
@@45auto82 I honestly don't know the real reason, but it seems to be a very common problem. I have several friends with early C4s with the same issue. Even if you get an alternator with higher amperage. I ended up redoing my entire radio system and it solved it.
I have a hard time believing that the original Bose radio could draw that much voltage... even though the eprom used to keep memory of the radio broadcasting station are old technology ... sure it draws some 25mA as well as the ECM when engine not running and key off. Most of the time when alternator go wrong it is because one of the diodes in the regulator is tired or cooked... when tired : 14V when running cold... then 11 or so when hot. Now I admit that if a short occurs in the radio amplifiers like power relays located inside the doors...(not really waterproof..) the case may happen.
Goos afternoon...everybody. I have a c4 1990 corvette and want to know what is the feelig gauge of the new iridium ones that you put into the vette. Tks...Albert from Aruba. GOD bless.
Had you the reverse it would have been catastrophic. Pistons hitting the plugs, plugs exploding into the cylinders, errant plug parts being sucked into the heads and valve train, subsequently destroying the engine.. Excellent catch by the viewer who alerted you..
Thanks for sharing that. I'll be sure to look at that when I work on my c4. Are you going to do another road test run, as before ,after you install the new exhaust? lol
ALWAYS use the plugs installed by the factory, if at all possible. There is nothing to be gained from any of the 'superior' aftermarket plugs, which are mostly marketing gimmicks. The exception would be a case where serious engine mods call for a change in what's called 'heat range'. Physical dimensions, heat range, and electrical resistance values must all be correct. The best way to ensure that is to run the OEM plugs.
@@mycorvettelife That's why I said "mostly" marketing gimmicks. The one advantage expensive plugs sometimes offer is longevity. But, while they cost 5-6 times as much, they don't last 5-6 times longer. Besides, new cars regularly go 100,000 miles on the original plugs. Hence, nothing to be gained. You didn't even address any of the things that are actually important: physical dimensions, heat range, and resistance. Too often, aftermarket plugs meet the physical dimension requirement, but heat range and/or resistance are incorrect. The best way to ensure you get the right values is to use OEM plugs, gapped to OEM specs. But hey, you're the expert. With only 50 years of experience, I haven't had time to learn much yet.
We’ve all been there man, in one form or another. Don’t beat yourself up too hard man. But think about how many people you just helped too. 😎
Chris, thank you for the shoutout and the kind words.
Your video will educate the early c4 owners of the different spark plugs.
A bit of history on the L98 cylinder heads. 1985 used the iron cylinder heads and was supposed to be the only year with the iron cylinder heads.
1986 started production with the aluminum heads and the heads started cracking around the lower head bolt bosses. These heads were replaced under warranty and there may have been a service campaign to get the heads replaced.
The legend is that all '86 convertibles are equipped with aluminum heads and all coupes after convertible introduction also have the aluminum heads.
Good stuff! 👍
I agree with Nash, we've ALL done something with ours "toys" that we look back on with just a touch of disgust, embarrassment, regret, thankful to have survived, etc... Thanks for your willingness to share all your Corvette experiences with us.
The chevy small block is such a good engine theres a reason why it was in production for more then 50 years
Hi Chris, my name is Alessandro and I live in Italy. I recently bought my Corvette C4 and I found all your videos very interesting.
I wanted to thank you and wish you good work for the future.
Thank you, see you soon
Chris, I glad it wasn’t the other way around. ( long reach plugs in a standard reach head).Could’ve been a costly mistake. Your videos are great and inspire other car enthusiasts to undertake these projects. Keep it Up!
Yeah man it would have been catastrophic.
the longer thread also provides more force to keep the plug in tight and aluminum being softer it protects the threads, anyway the pressure is like 1500psi or a bit higher so I guess they can hold at least for a while. The other reason is they get better cooling from the head.
does it have enough clearance to function properly if you put the longer aluminum ones in the iron head?@@rotorblade9508
with those short plugs the spark begins inside the cavity and should mean slightly longer flame propagation so it would need slightly more advance. Mechanically it puts twice as much stress on the aluminum threads and these engines are also pretty high in torque. there is also less heat dissipation through the treads but I don’t think it’s a problem
Bought a lo mileage 96 LT4. Decided to install fresh plugs and wires. Went to the trouble and expense to source correct GM plugs and red wires. When installing ,I found the #8 plug loose. Dodged a bullet there. She runs like a beast to be stock. Use only AC/Delco parts in your C4 when possible.
Again, I learned something new. Thank you Chris and thank you and Jonathan. just looking at the valve cover will let me know.
Great info! It's amazing what some of our co-corvette owners know and notice things that slip by the rest of others. It is great that we can pass info via this forum. 👍 Can't wait to hear the new c4 exhaust!!!
Thanks for the video! Mine was idling very weird at times, decided to just do the plugs, found out that the incorrect plugs were in also!
I bought my '88 in '89. After about 5 years, it was going through alternators almost yearly. I finally figured out what was going on. The alternator would fail on a hot SoCal day while stuck in traffic with the AC on MAX. I was getting Pep Boys "Lifetime" warranty alternators. They replaced each one without any explanation why they were failing so much. I actually read somewhere online how Pep Boys (and others) puts a very cheap Chinese diode set in the alternators. It would work ok in light or moderate loads. But, in a heavy load situation such as stop and go driving on a hot summer day, with the AC on high, one or more of the diodes would fail. So, I decided to cut my losses and NOT get my next alternator at Pep Boys. I bought a high amperage ($$$) alternator about 20 years ago and it is still working.
Do you have a link for it?
@@brutallybrutalbrutality6505 Sorry, that was too long ago. I probably bought a premium alternator through Amazon.
Great job Chris. You right none of us know everything about everything. I've found it to be a good practice to lay out the old parts and new parts and inspect them carefully. If they are visibly not the same then find out why. A big thumbs up to your viewer for catching that on the video. I wouldn't have ever noticed.
You can’t go wrong with the right spark plugs. Glad it worked for you! 👍
I actually did the opposite and put the long reach plugs for aluminum heads into my iron heads.. the old plugs were long reach too, good news is it never hit pistons or did anything horrible. Got the correct plugs back in it now.
Hello Chris doesn't blame you yourself it can happen to anyone and we've all learned from it I'm glad for you that there was no harm, Chris thanks.
Heres a tip from an old racer, If you have an engine that uses oil and fouls up plugs, like an old fork lift or farm implement etc, use a short reach plug in the thing and the plugs wont oil up, my old fork is running proof of that. As for your little gaff ? WELL this happens from time to time, after all we are ALL human. Keep up the good work fella and i will keep watching........ Eddie C4 Australia.
Im glad you willing to accept constructive criticism. Glad you fixed it on camera
That’s what this channel is about. Learning and teaching others.
On the C5, it could be your harmonic balancer that is causing the belt squawk issues
Yep, if that hot rod hasn't had a new balancer installed, it needs one.
I had the same issue, and replaced the harmonic balancer and the problem was solved.
I actually caught the shop I went to make this mistake but have since replaced the plugs with the proper .035 gapped (with the gasket) plugs. Also torqued to 12ft/lbs. Anyways, nice video!
Looking forward to the exhaust. Been trying to make a decision for my 87 convertible.
I have a magnaflow catback on mine and it sounds pretty great
At 7:11 the belt was on the side of the pulley..!😎 Ive got an 89 That I saved from the stripper and ive got the engine done and back in the car but it is running extra rich. No codes stored..
Did the same thing. Had no idea about 86 having the 2 different alloy/ iron heads! Of cause I got the wrong ones haha
I just installed mine yesterday and realized they are the wrong ones too.
I’m on my way to buy the correct ones and waiting for the cables to come in.
Double work.
I didn’t run the car.
Great videos. I noticed that your serpentine belt wasn't on when you said let's go start the car. I cringed seeing that. I'm sure the belt seated itself when you started the car, but still was scary to see. Keep up the great videos. C5 50th anniversary convertible owner myself.
I spotted that too. Depending on rotation, the belt will derail and shred itself. I speak from experience with my '88 C4. Like you, I also have a C5 50th Anniversary.
you just saved me from fkn myself... i got iron heads and i bought the aluminum head spark plugs
Lol I'll take the plugs lol
Love the C4 content.
Close call... Somebody had a good eye...
🌴Tip of the day:Brisk USA Spark Plugs are Totally Nuclear.🐂
You almost scared me. I bought these plugs for my LT1 engine. It seems they went back to that "wrong" design for the LT1 engines.
Hey everyone! I just wanted this video, thank you guys for the information! I just picked up an 86 c4 the other week, it’s due for some spark plugs. I’m confused after this video about which spark plugs to buy. Im unsure if it’s a late 86 or early.
Definitely subscribing to this guys channel I have a 94
Welcome !
Charlie Drobac lives in Mesa Az and I have an 1986 Corvette. I was going to purchase a new set of plugs
They have already been taken.
If you are getting low voltage off of your alternator, that's a common problem. It's because you don't have the factory radio in. I know, it sounds ridiculous, but I've gone through 4 alternators until a Corvette expert saw it. It usually happens when the car has heated up and the cooling fan kicks in. The best thing to do is find a factory replacement or redo the entire system. I was told that each speaker has it's own amplifier, therefore not any radio can work. However, there are some that make alternate radios. But you gotta look into that.
@ Harry Ballzak So you are saying the car can show low voltage when the cooling fan cranks on AND the wrong radio is on? Does it do it with radio off? Do you believe it is because the wrong radio draws too much AMPS? Just curious...not trying be ugly here. Thx.
@@45auto82 I honestly don't know the real reason, but it seems to be a very common problem. I have several friends with early C4s with the same issue. Even if you get an alternator with higher amperage. I ended up redoing my entire radio system and it solved it.
This is great stuff
What jack/lift is that on?
I have a hard time believing that the original Bose radio could draw that much voltage... even though the eprom used to keep memory of the radio broadcasting station are old technology ... sure it draws some 25mA as well as the ECM when engine not running and key off. Most of the time when alternator go wrong it is because one of the diodes in the regulator is tired or cooked... when tired : 14V when running cold... then 11 or so when hot. Now I admit that if a short occurs in the radio amplifiers like power relays located inside the doors...(not really waterproof..) the case may happen.
Great, informative video!! Hey...what's that music at the end where you have all 3 of your cars shown?? Catchy tune!
What do you think of underdrive pulleys? They claim 10 to 20 HP GAIN.
🤷♂️
Goos afternoon...everybody. I have a c4 1990 corvette and want to know what is the feelig gauge of the new iridium ones that you put into the vette. Tks...Albert from Aruba. GOD bless.
Were the correct plugs the NGK BKR4EIX?
Had you the reverse it would have been catastrophic. Pistons hitting the plugs, plugs exploding into the cylinders, errant plug parts being sucked into the heads and valve train, subsequently destroying the engine.. Excellent catch by the viewer who alerted you..
Do you send to Canada? I’m long time subscriber
👍👍
👍
I could use them👍🏾
Why was it making spark in the cylinder hole?
I put anti-seize on the threads,pain in the neck job
Yeah unfortunately I'm going to the same thing right now
Thanks for sharing that. I'll be sure to look at that when I work on my c4. Are you going to do another road test run, as before ,after you install the new exhaust? lol
Yep
What type of NGK plugs BKR…?
So 1985 use shorter plugs ??? Right
Interested in the plugs if they work for an 84 corvette
Already taken.
Spark plug gap is ???? .035 or .045
Either seems to work fine.
If someone had to tell you you’re putting in the wrong spark plugs, then you don’t need to be making videos on how to change C4 Corvette, spark plugs!
I'll take them off your hands. I have an 86 with iron heads and am right around the corner from you
Already taken.
Why it was running on the wrong sparkplugs? Simple: it's a Detroit iron! LOL
ALWAYS use the plugs installed by the factory, if at all possible. There is nothing to be gained from any of the 'superior' aftermarket plugs, which are mostly marketing gimmicks. The exception would be a case where serious engine mods call for a change in what's called 'heat range'. Physical dimensions, heat range, and electrical resistance values must all be correct. The best way to ensure that is to run the OEM plugs.
This is 100% false.
@@mycorvettelife
OK, explain why it's false.
Iridium or even Platinum plugs will absolutely last longer than standard plugs. There is plenty of research to back this up.
@@mycorvettelife
That's why I said "mostly" marketing gimmicks. The one advantage expensive plugs sometimes offer is longevity. But, while they cost 5-6 times as much, they don't last 5-6 times longer. Besides, new cars regularly go 100,000 miles on the original plugs. Hence, nothing to be gained.
You didn't even address any of the things that are actually important: physical dimensions, heat range, and resistance. Too often, aftermarket plugs meet the physical dimension requirement, but heat range and/or resistance are incorrect. The best way to ensure you get the right values is to use OEM plugs, gapped to OEM specs.
But hey, you're the expert. With only 50 years of experience, I haven't had time to learn much yet.