1986 Cutlass Supreme V8 307
July 2nd, 2023, 08:18 AM
#1
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Join Date: Jun 2023
Location: San Diego Ca
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1986 Cutlass Supreme V8 307
Hey! I just got my self a 1986 Cutlass Supreme V8 307. First time owning this type of car. What do you guys recommend for maintenance on the engine like what type of oil should I use? Has the original motor and it runs great.
Any tips will help to maintain this beautiful car going.
Also where or how do you guys buy parts for this type of car?
Thanks in advance
Any tips will help to maintain this beautiful car going.
Also where or how do you guys buy parts for this type of car?
Thanks in advance
July 2nd, 2023, 08:25 AM
#2
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Join Date: Oct 2009
Location: Poteau, Ok
Posts: 40,734
Periodically perform a tuneup, change the oil and filters as required, inspect the brakes and repair as necessary, etc etc. Most mechanical repair parts can be bought through your local auto parts store or any of the online options. Use Valvoline VR1 10w30 or equiv that has a zddp friction package for these old cars and a wix or NAPA gold oil filter. The owners manual will have all the required maintenance schedules.
July 2nd, 2023, 08:43 AM
#4
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,595
I'll add that your car has the CCC computer controlled Qjet. Get a factory Chassis Service Manual and follow the tune up and adjustment procedure EXACTLY. There are a million miles of vacuum lines on this car, and a crack or leak in any one of them will make the CCC system go apoplectic. If there's any question about the condition of the lines, get a couple of rolls of vacuum tubing and carefully replace them all. The CCC system uses an ancient 8-bit processor that was designed in the mid-1970s. It has very rudimentary programming and frankly most failures will not set a code since it lacks the computing horsepower to monitor the computer-controlled parts of the system.
July 2nd, 2023, 09:10 AM
#5
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Join Date: Aug 2011
Posts: 3,128
The above plus, don't touch the carburetor unless it is absolutely necessary. The carbs are very different than earlier ones and require a few special tools and knowledge. If the carb ever needs work have the suggested chassis service manual at the ready. Drive it, enjoy it, use the best parts when replacing anything and don't let it sit too much.
July 2nd, 2023, 09:17 AM
#6
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Join Date: Jan 2010
Posts: 1,973
If you plan on keeping the car stock, or stock-ish, your most valuable investment is---
---the chassis service manual, aka CSM. Buy one for your car. The GM one. Nothing else will do as good for your car. And get the complete set with the wiring diagrams as well. I believe in 86 they included the electrical diagrams in the back of the book. I have 69, 70, 71, 84, 85, and 87 sets, and I would never hesitate to crack them open to learn more about that year car. The fisher body manual also helps too, but those are more generic with few specifics about G-bodies.
$15 with free shipping...can't beat that.
https://www.ebay.com/itm/266225791317
I think there's also CD versions of the manuals plus the body manual out there as well, although I can't speak for the quality of the print. Those would come in handy if you were going to do a procedure and print out the pages you need, grease them up and toss them when you're done. No messed up manuals. JMO.
You haven't told us the miles, condition, or anything about the car, so depending on condition, would depend on where you want to throw money at it first.
Secondly, I'd do a general maintenance check/procdures to establish a new baseline. If you have your owner's manual, it comes with a good guide in it when and what minor maintenance items to do. Invest in a couple spools of 7/32 and 9/32 size vacuum lines or know where to get lengths of it as needed. Vacuum leaks are commonplace on these old cars and with the CCC system, it's critical that you have no vacuum leaks. Grab the hoses and flex them and check for cracks/breaks. Replace them ONE BY ONE as needed so you don't get lost. A lot of spaghetti under the hood. Also, check the torque on the carburetor hold down bolts. They like to get loose over time and cause air leaks. While you're in there, consider putting in a new fuel filter. If original carb, you would need GM ACDelco filter GF471.
You have a roller cam in that thing, and not a lot of power. However, the timing chains on these 307s always came with the nylon cam gear teeth and they mostly end up cracking and falling off into the pan, and if enough teeth are lost, you could jump time. It can happen. Not unusual. Also, the aluminum intakes on the steel block/heads/gaskets like to corrode and leak at the corners, so look for mystery corner intake coolant leaks. Another not so uncommon issue.
With the roller cam, you won't NEED a bunch of zddp in the oil. But it won't hurt. Just don't go crazy. The catalytic converter can be harmed and **** the bed if you use too much. I use Mobil 1 5w-30 synthetic in my 87 442 with the roller cam. Regular oil change intervals and a good filter will be fine. Wix 51045, or even the OLDER GM filters. PF45, GM p/n 25010324. I think they changed it to PF61 and then PF61E or something, but I'm not too sure about those.
I'd also change the coolant, belts and hoses, plus the rear end fluid as well. Any good 75W-90 gear oil should work. Specs call for SAE 80W, or SAE 80W-90 GL5. If you have limited slip (G80 on your trunk sticker) you would need to add a bottle of GM limited slip additive. GM p/n 88900330. About 5 or 6 bucks average. As far as the transmission, you would likely need Dexron III, although the more expensive Dexron VI would work. You'll find it under Dex/Merc most likely. Check the condition of the fluid first though. If not many miles and it still looks pink and not burnt smell and the transmission still shifts well...it may be something that can wait.
If the front wheel bearings haven't been repacked with grease, they're due every 30,000 miles and/or brake relining/pad replacement if it's not an HD service vehicle. While you're there, you can check your brake pad life as well and fix that if needed.
Rotor cap is ACDelco D336 or D336X. The rotor is D433. Spark plug wire set is ACDelco 608B. The spark plugs are Delco FR3LS6. I'd gap them to 0.045" although they say to set them to 0.060". Too much strain on the coil at 0.060" IMO, and 0.045" works just fine with the HEI.
THAT should get you started.
---the chassis service manual, aka CSM. Buy one for your car. The GM one. Nothing else will do as good for your car. And get the complete set with the wiring diagrams as well. I believe in 86 they included the electrical diagrams in the back of the book. I have 69, 70, 71, 84, 85, and 87 sets, and I would never hesitate to crack them open to learn more about that year car. The fisher body manual also helps too, but those are more generic with few specifics about G-bodies.
$15 with free shipping...can't beat that.
https://www.ebay.com/itm/266225791317
I think there's also CD versions of the manuals plus the body manual out there as well, although I can't speak for the quality of the print. Those would come in handy if you were going to do a procedure and print out the pages you need, grease them up and toss them when you're done. No messed up manuals. JMO.
You haven't told us the miles, condition, or anything about the car, so depending on condition, would depend on where you want to throw money at it first.
Secondly, I'd do a general maintenance check/procdures to establish a new baseline. If you have your owner's manual, it comes with a good guide in it when and what minor maintenance items to do. Invest in a couple spools of 7/32 and 9/32 size vacuum lines or know where to get lengths of it as needed. Vacuum leaks are commonplace on these old cars and with the CCC system, it's critical that you have no vacuum leaks. Grab the hoses and flex them and check for cracks/breaks. Replace them ONE BY ONE as needed so you don't get lost. A lot of spaghetti under the hood. Also, check the torque on the carburetor hold down bolts. They like to get loose over time and cause air leaks. While you're in there, consider putting in a new fuel filter. If original carb, you would need GM ACDelco filter GF471.
You have a roller cam in that thing, and not a lot of power. However, the timing chains on these 307s always came with the nylon cam gear teeth and they mostly end up cracking and falling off into the pan, and if enough teeth are lost, you could jump time. It can happen. Not unusual. Also, the aluminum intakes on the steel block/heads/gaskets like to corrode and leak at the corners, so look for mystery corner intake coolant leaks. Another not so uncommon issue.
With the roller cam, you won't NEED a bunch of zddp in the oil. But it won't hurt. Just don't go crazy. The catalytic converter can be harmed and **** the bed if you use too much. I use Mobil 1 5w-30 synthetic in my 87 442 with the roller cam. Regular oil change intervals and a good filter will be fine. Wix 51045, or even the OLDER GM filters. PF45, GM p/n 25010324. I think they changed it to PF61 and then PF61E or something, but I'm not too sure about those.
I'd also change the coolant, belts and hoses, plus the rear end fluid as well. Any good 75W-90 gear oil should work. Specs call for SAE 80W, or SAE 80W-90 GL5. If you have limited slip (G80 on your trunk sticker) you would need to add a bottle of GM limited slip additive. GM p/n 88900330. About 5 or 6 bucks average. As far as the transmission, you would likely need Dexron III, although the more expensive Dexron VI would work. You'll find it under Dex/Merc most likely. Check the condition of the fluid first though. If not many miles and it still looks pink and not burnt smell and the transmission still shifts well...it may be something that can wait.
If the front wheel bearings haven't been repacked with grease, they're due every 30,000 miles and/or brake relining/pad replacement if it's not an HD service vehicle. While you're there, you can check your brake pad life as well and fix that if needed.
Rotor cap is ACDelco D336 or D336X. The rotor is D433. Spark plug wire set is ACDelco 608B. The spark plugs are Delco FR3LS6. I'd gap them to 0.045" although they say to set them to 0.060". Too much strain on the coil at 0.060" IMO, and 0.045" works just fine with the HEI.
THAT should get you started.
Last edited by 69HO43; July 2nd, 2023 at 09:20 AM.
July 2nd, 2023, 10:02 AM
#7
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,595
A quality oil and frequent changes are more important than the "best" oil. Wix 51045 filter for these engines. As I said above, regular Castrol is what I use but frankly any brand name oil today is higher quality than when these engines were designed.
July 2nd, 2023, 10:06 AM
#9
Registered User
Thread Starter
Join Date: Jun 2023
Location: San Diego Ca
Posts: 7
If you plan on keeping the car stock, or stock-ish, your most valuable investment is---
---the chassis service manual, aka CSM. Buy one for your car. The GM one. Nothing else will do as good for your car. And get the complete set with the wiring diagrams as well. I believe in 86 they included the electrical diagrams in the back of the book. I have 69, 70, 71, 84, 85, and 87 sets, and I would never hesitate to crack them open to learn more about that year car. The fisher body manual also helps too, but those are more generic with few specifics about G-bodies.
$15 with free shipping...can't beat that.
https://www.ebay.com/itm/266225791317
I think there's also CD versions of the manuals plus the body manual out there as well, although I can't speak for the quality of the print. Those would come in handy if you were going to do a procedure and print out the pages you need, grease them up and toss them when you're done. No messed up manuals. JMO.
You haven't told us the miles, condition, or anything about the car, so depending on condition, would depend on where you want to throw money at it first.
Secondly, I'd do a general maintenance check/procdures to establish a new baseline. If you have your owner's manual, it comes with a good guide in it when and what minor maintenance items to do. Invest in a couple spools of 7/32 and 9/32 size vacuum lines or know where to get lengths of it as needed. Vacuum leaks are commonplace on these old cars and with the CCC system, it's critical that you have no vacuum leaks. Grab the hoses and flex them and check for cracks/breaks. Replace them ONE BY ONE as needed so you don't get lost. A lot of spaghetti under the hood. Also, check the torque on the carburetor hold down bolts. They like to get loose over time and cause air leaks. While you're in there, consider putting in a new fuel filter. If original carb, you would need GM ACDelco filter GF471.
You have a roller cam in that thing, and not a lot of power. However, the timing chains on these 307s always came with the nylon cam gear teeth and they mostly end up cracking and falling off into the pan, and if enough teeth are lost, you could jump time. It can happen. Not unusual. Also, the aluminum intakes on the steel block/heads/gaskets like to corrode and leak at the corners, so look for mystery corner intake coolant leaks. Another not so uncommon issue.
With the roller cam, you won't NEED a bunch of zddp in the oil. But it won't hurt. Just don't go crazy. The catalytic converter can be harmed and **** the bed if you use too much. I use Mobil 1 5w-30 synthetic in my 87 442 with the roller cam. Regular oil change intervals and a good filter will be fine. Wix 51045, or even the OLDER GM filters. PF45, GM p/n 25010324. I think they changed it to PF61 and then PF61E or something, but I'm not too sure about those.
I'd also change the coolant, belts and hoses, plus the rear end fluid as well. Any good 75W-90 gear oil should work. Specs call for SAE 80W, or SAE 80W-90 GL5. If you have limited slip (G80 on your trunk sticker) you would need to add a bottle of GM limited slip additive. GM p/n 88900330. About 5 or 6 bucks average. As far as the transmission, you would likely need Dexron III, although the more expensive Dexron VI would work. You'll find it under Dex/Merc most likely. Check the condition of the fluid first though. If not many miles and it still looks pink and not burnt smell and the transmission still shifts well...it may be something that can wait.
If the front wheel bearings haven't been repacked with grease, they're due every 30,000 miles and/or brake relining/pad replacement if it's not an HD service vehicle. While you're there, you can check your brake pad life as well and fix that if needed.
Rotor cap is ACDelco D336 or D336X. The rotor is D433. Spark plug wire set is ACDelco 608B. The spark plugs are Delco FR3LS6. I'd gap them to 0.045" although they say to set them to 0.060". Too much strain on the coil at 0.060" IMO, and 0.045" works just fine with the HEI.
THAT should get you started.
---the chassis service manual, aka CSM. Buy one for your car. The GM one. Nothing else will do as good for your car. And get the complete set with the wiring diagrams as well. I believe in 86 they included the electrical diagrams in the back of the book. I have 69, 70, 71, 84, 85, and 87 sets, and I would never hesitate to crack them open to learn more about that year car. The fisher body manual also helps too, but those are more generic with few specifics about G-bodies.
$15 with free shipping...can't beat that.
https://www.ebay.com/itm/266225791317
I think there's also CD versions of the manuals plus the body manual out there as well, although I can't speak for the quality of the print. Those would come in handy if you were going to do a procedure and print out the pages you need, grease them up and toss them when you're done. No messed up manuals. JMO.
You haven't told us the miles, condition, or anything about the car, so depending on condition, would depend on where you want to throw money at it first.
Secondly, I'd do a general maintenance check/procdures to establish a new baseline. If you have your owner's manual, it comes with a good guide in it when and what minor maintenance items to do. Invest in a couple spools of 7/32 and 9/32 size vacuum lines or know where to get lengths of it as needed. Vacuum leaks are commonplace on these old cars and with the CCC system, it's critical that you have no vacuum leaks. Grab the hoses and flex them and check for cracks/breaks. Replace them ONE BY ONE as needed so you don't get lost. A lot of spaghetti under the hood. Also, check the torque on the carburetor hold down bolts. They like to get loose over time and cause air leaks. While you're in there, consider putting in a new fuel filter. If original carb, you would need GM ACDelco filter GF471.
You have a roller cam in that thing, and not a lot of power. However, the timing chains on these 307s always came with the nylon cam gear teeth and they mostly end up cracking and falling off into the pan, and if enough teeth are lost, you could jump time. It can happen. Not unusual. Also, the aluminum intakes on the steel block/heads/gaskets like to corrode and leak at the corners, so look for mystery corner intake coolant leaks. Another not so uncommon issue.
With the roller cam, you won't NEED a bunch of zddp in the oil. But it won't hurt. Just don't go crazy. The catalytic converter can be harmed and **** the bed if you use too much. I use Mobil 1 5w-30 synthetic in my 87 442 with the roller cam. Regular oil change intervals and a good filter will be fine. Wix 51045, or even the OLDER GM filters. PF45, GM p/n 25010324. I think they changed it to PF61 and then PF61E or something, but I'm not too sure about those.
I'd also change the coolant, belts and hoses, plus the rear end fluid as well. Any good 75W-90 gear oil should work. Specs call for SAE 80W, or SAE 80W-90 GL5. If you have limited slip (G80 on your trunk sticker) you would need to add a bottle of GM limited slip additive. GM p/n 88900330. About 5 or 6 bucks average. As far as the transmission, you would likely need Dexron III, although the more expensive Dexron VI would work. You'll find it under Dex/Merc most likely. Check the condition of the fluid first though. If not many miles and it still looks pink and not burnt smell and the transmission still shifts well...it may be something that can wait.
If the front wheel bearings haven't been repacked with grease, they're due every 30,000 miles and/or brake relining/pad replacement if it's not an HD service vehicle. While you're there, you can check your brake pad life as well and fix that if needed.
Rotor cap is ACDelco D336 or D336X. The rotor is D433. Spark plug wire set is ACDelco 608B. The spark plugs are Delco FR3LS6. I'd gap them to 0.045" although they say to set them to 0.060". Too much strain on the coil at 0.060" IMO, and 0.045" works just fine with the HEI.
THAT should get you started.
Great information thank you. Thanks for the manual reference definitely getting that.
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