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Thanks for allowing us to join your group. Looking forward to participating in anyway we can.
My son and I recently purchased a 1966 Delta 88 Holiday Coupe
with a 425 cu in 4 barrel engine in it. As far as we know the engine is stock with a rebuild done a few years ago. We have been told it was bored out 0.30 over and that’s about it. When sitting for a day or two it’s requires about 5-6 kicks on the gas peddle to start, even then there’s some cranking going on. Once it does start it stays on high idle for quite sometime. Seems to idle okay but after driving for a bit and the engine is warm while in gear it gets really rough. Because all we’ve done so far is drive and enjoy it we haven’t really dug into anything yet. The car seems very sluggish, when driving and under hard acceleration the trans kicks down and it really doesn’t go anywhere. Off the line it’s also a dog. We are looking for a starting point as we will be starting our work on it this weekend. Wish I could offer more information but we haven’t delved into anything yet.
The starting point is probably a tune up and resetting the choke. It is not abnormal to have to pump the gas pedal a few times to get the car to start after sitting a few days.
Just on the face of what you describe, sounds like the choke is sticking. However, I agree with the others that a complete tuneup is mandatory. If that doesn't solve your problem, a carb rebuild may be in your future -- I believe '66 was the first year for the Q-Jet in these cars.
Regardless, I agree with SB -- one of the first things to do before you spend a bunch of money is a compression test. This will give you a better idea of what you're dealing with.
I also concur with the others that it's a very nice car.
Awesome car , like the 2 door models. Both 425 engines here starts with 1 kick at the gas peddle when they
have sit for some weeks and not much cranking on the starter.
I owned a ‘67 Delta 88 convertible (sold it in 2020) that had a 425 with a 2-barrel, and that car had some nice pep. In stock condition, when new, your car was certainly not lazy.
I did rebuild the carburetor on mine, and I suggest you do that. Do the tune-up everyone suggests as well. I’d start with that (new plugs, wires, ignition coil, points, check timing, etc.) and see what that does all by itself.
I would also check all vacuum hoses for any leaks. Along with testing the compression, put a vacuum gauge on it and see what you get at idle. It ought to be somewhere around 15 psi and, most importantly, hold steady. If it doesn’t do these things, look for leaks.
One thing I would not do is go nuclear and start throwing at it all sorts of costly, aftermarket presumed performance enhancements. Make sure the basics are working right before you decide that you’re still not happy with the power and want to start making modifications.
As mentioned look at the ignition system from the plugs up to the distributor...
Verify the vacuum canister functions, points condition and setting, and centrifugal weights are free.
Set dwell at .016" or 30° dwell angle.
Read the plugs. They will tell you what the fuel system is doing.
Give the engine as much timing as it will take without spark knock. (typically 12-14° base).
Use a vacuum meter hooked to the intake to adjust the timing and air-fuel mix together.
You want the highest vacuum reading possible at a warm curb idle. Don't pay attention to what the book says about the timing spec.
The carb may need a rebuild. Exhaust all of the tuning items before moving to the carb. How's the fuel filter?
Run high-octane non-ethanol gas.
Resist buying aftermarket or big box rebuilt items.
Never turn in your parts for core charges, especially if OEM originals.
Get it all rebuilt by a reputable company that uses USA made components.
We can help you locate the right parts vendors or rebuilding services. From alternators, water pumps, starters, wiper motors, to USA made wheel bearings and grease seals et al.
Change ALL of the fluids in this car...trans, brake, pw steering, coolant, diff. Inspect the soft brake and fuel lines for deterioration. Tires 10+ years old replace.
Do you have collector car agreed value insurance???
Just on the face of what you describe, sounds like the choke is sticking.
Originally Posted by ourkid2000
Let's get a look at that carb. It certainly seems like you could have a simple problem with your choke. Start simple right!
Also note that if the choke is not opening fully, the secondary lockout will prevent the secondary air valves from opening at full throttle, which will drastically reduce the engine's power.
One last thought........check to make sure the "Switch pitch" transmission is functioning properly. If its not going to "high stall", it could feel "doggy".
One last thought........check to make sure the "Switch pitch" transmission is functioning properly. If its not going to "high stall", it could feel "doggy".
Other than checking if it's good electrically, how can you even test this?
The starting point is probably a tune up and resetting the choke. It is not abnormal to have to pump the gas pedal a few times to get the car to start after sitting a few days.
been awhile since I had to that but yes your right. Thanks
As mentioned look at the ignition system from the plugs up to the distributor...
Verify the vacuum canister functions, points condition and setting, and centrifugal weights are free.
Set dwell at .016" or 30° dwell angle.
Read the plugs. They will tell you what the fuel system is doing.
Give the engine as much timing as it will take without spark knock. (typically 12-14° base).
Use a vacuum meter hooked to the intake to adjust the timing and air-fuel mix together.
You want the highest vacuum reading possible at a warm curb idle. Don't pay attention to what the book says about the timing spec.
The carb may need a rebuild. Exhaust all of the tuning items before moving to the carb. How's the fuel filter?
Run high-octane non-ethanol gas.
Resist buying aftermarket or big box rebuilt items.
Never turn in your parts for core charges, especially if OEM originals.
Get it all rebuilt by a reputable company that uses USA made components.
We can help you locate the right parts vendors or rebuilding services. From alternators, water pumps, starters, wiper motors, to USA made wheel bearings and grease seals et al.
Change ALL of the fluids in this car...trans, brake, pw steering, coolant, diff. Inspect the soft brake and fuel lines for deterioration. Tires 10+ years old replace.
Do you have collector car agreed value insurance???
I’m wowed by all the great information you are all passing onto us, really really appreciate you all and the info. Our plan was to do all the fluids as recommended by the group. It’s been over 30 years since I’ve messed around with these types of engines etc…Hope it’s like riding a bicycle lol. Keep you all posted.
The starting point is probably a tune up and resetting the choke. It is not abnormal to have to pump the gas pedal a few times to get the car to start after sitting a few days.
Exactly on tune, etc. And my ride can start easy or be difficult depending on the weather. 3 pumps, crank and instantly on after a week. Or sit a week and 3 pump crank no, 3 pump crank no, 3 pump crank on. And that's actually literal from the past few weeks, as I keep a loose diary on my ride. Humidity definitely bothers her and the choke is wonky. If I start her every day good weather 3 pumps crank on every time. When in a garage, 1 pump crank on.
Originally Posted by Oldmanitoban
stock with a rebuild done a few years ago.
The car seems very sluggish
One of the reasons I am not looking forward to having my engine rebuilt till there is absolutely no choice. Your observations are a very common compliant on recent rebuilds (barely used engines). Have friends and acquaintances that have been disappointed at least initially. Closest to me, one was a mild Olds 455 (Edelbrock performer cam kit, 3 angle valve job, etc) the other a built Chevy 454 (LS6 territory). Both done professionally. After build fine tuning and corrected timing very important...
Originally Posted by Oldmanitoban
Off the line it’s also a dog.
Keep in mind these are 4200 lb cars. 800 lbs heavier than 66 Cutlasses. They are powerful but don't feel nimble. If you are used to 5 second 0-60s these models can take up to 10 seconds... Beautiful car by the way.
