1966 Pontiac Catalina Convertible - Engine

[Solittle]

I'm looking at a 1966 Pontiac convertible with a the original 389 CI 275 hp with a two barrel carb.

Can I run this as a daily driver with todays fuel? What grade fuel? Will I need additives & if so what? The owner says he adds a bit of racing fuel once in a while but I do not want to get into that.

Any advice on this or other tips on this combo?

 

[eastont]

Re: 1966 Pontiac Catalina Convertible - Engine

You can run it with today's unleaded fuel, but the timing will have to be adjusted to compensate for the different way the fuel burns. I think it is to be retarded 15 degrees, but I forget exactly, it's been awhile.
Make sure you take it to a mechanic who is familiar with this, not a guy just out of college.......
Also try to ensure there is very little on no ethenol in the fuel. It will ping no matter what you do. I've tried various additives and not found one yet.
Good luck, it's a nice car.

 

[bruceb58]

Re: 1966 Pontiac Catalina Convertible - Engine

You can run it with today's unleaded fuel, but the timing will have to be adjusted to compensate for the different way the fuel burns.

It burns the same, it just doesn't have lead in it now. You may have to use premium fuel though.

I think it is to be retarded 15 degrees, but I forget exactly, it's been awhile.

No way!

Also try to ensure there is very little on no ethenol in the fuel. It will ping no matter what you do. I've tried various additives and not found one yet.

ethanol actually raises the octane.

Bottom line to the OP. Since the engine was designed to run with leaded fuel, your valve seats will wear after a certain amount of time. At that time, you get thge heads re-done. That is if they haven't already been done. if the car does ping because it is now running on slightly lower octane and it is a high compression engine, back off the timing a few degrees off of spec. If it still pings, repeat until it stops pinging under load. You may have more ping due to carbon build up on the pistons as well than due to the compression issue.

 

[Bigprairie1]

Re: 1966 Pontiac Catalina Convertible - Engine

I believe that 389 is part of the 'trophy' series of engines offered in the big pontiacs in the late 50's to early/mid 60's. This engine series was offered in different hp's all the up to 'theoretically' 376hp.
The motor you have (275hp/2bbl) however is not the higher compression model...it is something more like 9 to 9.5. It was designed at the time to be more economic and to run on 'regular' fuel for the time. So if you might get away with running 89 octane in it..with maybe the odd tank of 91 just for good measure.
That said, if you go have the heads rebuilt with new guides you will be good to go and not have to add additives to the engine. They changed the head/ valve guide design in the early 70's to have the valve guides lubricated without non-leaded fuel.
If the rest of the head (and valves) are in good shape this should not cost too much.
Good luck and keep us posted.
BP

 

[Solittle]

Re: 1966 Pontiac Catalina Convertible - Engine

Thanks for thee quick response so far. I have just seen the car for a few moments and it looks cherry at first impression. Red with black interior and top. The owner claims that it is a Florida car with the original papers, matching numbers and 87K miles. Very minor rust. He also has a 58 vette & GTO of some vintage.

My wife will kill me - - - - but I gotta look!!

 

[avenger79]

Re: 1966 Pontiac Catalina Convertible - Engine

another issue may be rubber seals in carb and what not due to eythanol in fuel. i had heard they break down with new fuels.
change valve seats as already said. remember there are plenty of guys out there running old cars with no probs. we have a 74 Torino and a 73 VW that both run regularly with no issues.

 

[Solittle]

Re: 1966 Pontiac Catalina Convertible - Engine

Forgot to ask you guys what you think this car might be worth assuming great condition but perhaps not at show winner quality?

What I have seen on the internet goes all over the palce from a low of $3k to well over $30K.

 

[avenger79]

Re: 1966 Pontiac Catalina Convertible - Engine

hard to say without seeing it, but with the orig 389 it's value is quite a bit higher. most people swapped them out for 400's.

i had a 66 bonneville when i was in high school. fun car. (that was many years ago) i got it for $25 out of some guys front yard.

 

[Bob_VT]

Re: 1966 Pontiac Catalina Convertible - Engine

That said, if you go have the heads rebuilt with new guides you will be good to go and not have to add additives to the engine. They changed the head/ valve guide design in the early 70's to have the valve guides lubricated without non-leaded fuel.
If the rest of the head (and valves) are in good shape this should not cost too much.
Good luck and keep us posted.
BP

Absolutely worth the change along with any rubber carb parts too and never worry again.

 

[j_martin]

Re: 1966 Pontiac Catalina Convertible - Engine

It was designed to run on regular of the time, which was about 93 octane. High octane was 98 - 100. I would expect it would run fine on 92 octane non-oxygenated (no ethanol) fuel, sold around here for classic cars. For sure you'd have to back off the timing a bit to run 89 octane. 87 would be pushing it. Altitude reduces octane requirements across the board.

The equivalent fuel for 60's high octane is av gas 100LL.

The timing mark in those old engines were on the harmonic damper, and sometimes weren't real accurate. We always timed them by ear, setting the timing to just before it would ping at full throttle mid RPM.

I have greatly extended the mileage without sacrificing performance with a 4 bbl carb by rigging a solenoid driven linkage that locks out the secondary throttles and advances the timing until the solenoid is energized, retarding the timing 10 - 15 degrees and letting the secondaries go. With 2 bbl yer stuck with base timing.

hope it helps
John

 

[rbh]

Re: 1966 Pontiac Catalina Convertible - Engine

If your going to tear the heads off, you might want to think about hardend seats and valves, I am pretty sure thats one thing that that will give you alittle more life out of your motor.

 

[WIMUSKY]

Re: 1966 Pontiac Catalina Convertible - Engine

Thanks for thee quick response so far. I have just seen the car for a few moments and it looks cherry at first impression. Red with black interior and top. The owner claims that it is a Florida car with the original papers, matching numbers and 87K miles. Very minor rust. He also has a 58 vette & GTO of some vintage.

My wife will kill me - - - - but I gotta look!!

If it's a numbers matching car, you need to verify it yourself. You don't want to pay for numbers matching only to find out later it isn't. Does his paperwork include a build sheet, invoice etc? There's alot to decode to verify it is numbers matching. Date codes for the heads, block, tranny and rearend. Block/heads casting number, engine code. You get the picture. You need to know what you're looking for and where to find it.

One example, there were no 275hp, 389's in '66 from the factory.
Here's what was available:
1966 389 256HP 091 1.92/1.66 8.6 c.r.
1966 389 290,325,333HP 092 1.92/1.66 10.5 c.r.
1966 389 335,360HP 093 1.92/1.66 10.5 c.r.
What hp it is depends on what the casting code is, 091,092 or 093. Is the motor/heads from a '66 "for sure"? The only way to tell is to decode it. What does the data plate say for options. That needs to be decoded.

Here's the best resource for Pontiac factory options. You can fill it out online and for $50 find out exactly what that car was born with. You just need to supply the V.I.N. For an extra $15 they'll fax the info so you can get it in your hands immediately...

http://www.phs-online.com/

Being a Catalina it wont be "cloned" like turning a Lemans into a GTO. But, it may not have the original running gear.

Also, always run premium.... Good luck!

 

[Solittle]

Re: 1966 Pontiac Catalina Convertible - Engine

Thanks to all - I did look at one beautiful unrestored and extemely well maintained 66 Catalina. I am not a car nut but in my opinion it would not take an awful lot to present this car as near factory original. It does have after market chrome valve covers, a chrome air cleaner and oversize non factory rims & tires. In all other aspects it is in far better condition that I would expect in a car that is 44 years old with 87K miles.

O.K. so what did I do? Well I did drive it and except for a tire rub in sharp trurns caused by the wide tires it ran pefectly. When I started thinking about this a couple of days ago I got all hoped up and excited remembering the absolute joy I felt driving my 59 Olds convertible backin my college days. But today much to my surprise I did not get the emotional high that I expected. Then I asked myself what would I do with it if I did get it. I kinda think I would get bored after a few months. Soooo - - The guy has ofered to let me take it for a couple of hours for a drive with my family. I may do that yet but then again may pass.

By the way if you are interested send me a private message with a way to contact you. The seller is asking $12.5K and the car is in Miam, fl.

As a footnote I nearly flipped when I got to the sellers house. He lives in a nice residential area on a 1/2 acre lot. Back behind his pool/patio is his his garage. It is a two story twin bay full blown garage with a lift on one side. The Pontiac was on the bottom of the lift with a cherry GTO above it. In the other bay was his wife's play car - a 65 vette that looked as if it had just rolled off the showroom floor.

Guys and thier toys!! For now I think I'll clean up my boat.

Again thanks -