1977 911s
09-18-2006, 02:30 PM
#2
Race Car
There are lots of things to look for. You should not buy any 911 without an independent shop doing a pre-purchase inspection. With 1974-77 cars, this is even more important. See the sticky thread on this forum with Peter Zimmerman's article on PPI's.
Understand going in that 1977 might represent the worst year ever for the 911. The soft magnesium engine cases let headstuds pull out. Thermal reactors used as a quick fix for U.S. emissions cooked the engines. (I can't remember now for sure if 49-state cars had them in 1977, but I think they did.) Five-blade cooling fans made the situation even worse. For a model labeled 'S,' power relative to weight was at an all-time low. Even more than other pre-89 911's, they typically cost double or triple to restore what they end up being worth.
That said, they're great cars. Lighter than other impact-bumper cars and distinct looking with the narrow-body look. With the right details taken care of in an engine rebuild, and other things (like the magnesium-cased transaxle) being maintained and rebuilt, they can be great bargains.
But most of the ones out there are not bargains. Don't leap without a mechanic going through the car first. And don't buy it if the seller won't allow that. There's a reason they're frequently sold to first-time 911 owners.
Understand going in that 1977 might represent the worst year ever for the 911. The soft magnesium engine cases let headstuds pull out. Thermal reactors used as a quick fix for U.S. emissions cooked the engines. (I can't remember now for sure if 49-state cars had them in 1977, but I think they did.) Five-blade cooling fans made the situation even worse. For a model labeled 'S,' power relative to weight was at an all-time low. Even more than other pre-89 911's, they typically cost double or triple to restore what they end up being worth.
That said, they're great cars. Lighter than other impact-bumper cars and distinct looking with the narrow-body look. With the right details taken care of in an engine rebuild, and other things (like the magnesium-cased transaxle) being maintained and rebuilt, they can be great bargains.
But most of the ones out there are not bargains. Don't leap without a mechanic going through the car first. And don't buy it if the seller won't allow that. There's a reason they're frequently sold to first-time 911 owners.
09-18-2006, 03:50 PM
#3
Rennlist Member
Jack makes lots of good points, but I would like to offer a minor correction and a couple of observations. The transmission, type 915/61 with aluminum case was first used in '77 models, and was fitted with the hook-style clutch cable used through '86 production. '77s also received some nice bits, such as aluminum chain tensioner housings, and, finally, better valve guides that will last well past a 100K miles if given the chance (removal of those pesky thermal reactors and the use of high quality oil both help in this regard). '77s are good cars, but as Jack pointed out, a PPI by an experienced 911 mechanic is a must!
Pete
Pete
09-18-2006, 04:16 PM
#5
Drifting
Thermal Reactor is a round metal cylinder that is located underneath the motor that is designed to generate tons of heat to reduce emissions which also results in fried valve guides, oil leaks and all sorts of other problems.
They are required in some states to pass visual emission inspections.
Another item to consider is that not many shops know how to rebuild a 2.7 motor properly since the magnesium cases tent to warp with heat. Usually you might be better off swapping with a 3.0 liter if the miles are very high and it needs a rebuild.
I almost purchased a 77 911s with 65,000 miles on it. The car was a gem and it only had 5,000 since the top-end was overhauled and case-savers were installed. Thermal-Reactors were reinstalled on the motor and it was already starting to leak quite a bit onto the heat exchangers.
They are required in some states to pass visual emission inspections.
Another item to consider is that not many shops know how to rebuild a 2.7 motor properly since the magnesium cases tent to warp with heat. Usually you might be better off swapping with a 3.0 liter if the miles are very high and it needs a rebuild.
I almost purchased a 77 911s with 65,000 miles on it. The car was a gem and it only had 5,000 since the top-end was overhauled and case-savers were installed. Thermal-Reactors were reinstalled on the motor and it was already starting to leak quite a bit onto the heat exchangers.
09-18-2006, 05:32 PM
#6
Poseur
Rennlist Member
Rennlist Member
Porsche AG had to come up with a design compromise in 1977 as they were trying to hold up going completely to catalytic converters. As such the thermal reactor design resulted. They are part of the exhaust headers (between the heads and the heat exchangers) and added a significant amount of weight to the engines as well as heat,--really not a great idea for those magnesium cased-air cooled motors. Along with the thermal reactors were injectors that injected fresh air into the engines in that area. There should also be an additional little belt-driven fresh air pump (on the left of the central fan) and roughly over the distributor cap). That little pump injects fresh air into the system down below to help with the burning of unburned hydrocarbons within the thermal reactors. When thermal reactors are removed from an EPA compliant car, the fresh air injectors should also be removed and the holes in the bottom of the heads need to be plugged. At that point that little pump on the left side of the motor can be removed as well.
Thermal reactors were the worst thing ever conceived by Zuffenhausen and they seriously detract from the life of the engine,--adding nothing but heat to an area that is already too hot. A word of caution: Leaking oil onto the heat exchangers can ultimately result in a fire down there if the timing of the car is off (retarded) and the headers get cherry red. (Ask me how I know).
The 1977 cars were the first to get the central fresh air vents, and the first to get the recessed door locks. They also received a large brake booster seen in the trunk. So many better things showed up inthe 1978 911SC cars that the 1977 911S was quickly outdated and less popular to restore. It is the last of the so-called 'narrow body' 911 cars.
Thermal reactors were the worst thing ever conceived by Zuffenhausen and they seriously detract from the life of the engine,--adding nothing but heat to an area that is already too hot. A word of caution: Leaking oil onto the heat exchangers can ultimately result in a fire down there if the timing of the car is off (retarded) and the headers get cherry red. (Ask me how I know).
The 1977 cars were the first to get the central fresh air vents, and the first to get the recessed door locks. They also received a large brake booster seen in the trunk. So many better things showed up inthe 1978 911SC cars that the 1977 911S was quickly outdated and less popular to restore. It is the last of the so-called 'narrow body' 911 cars.
09-18-2006, 06:30 PM
#7
Instructor
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I think im going to wait until a better deal comes around...I dont think I want to deal with the 2.7 and all its problems. Thanks guys...dont know what id do without you.
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09-18-2006, 09:29 PM
#8
Don't run too fast! At least check and see if the car has a 3L motor in it - that solves most problems. You can post the engine # here and people can tell you what type it is.
IF the price is low enough, then the car may be worth it. The '77 does have full galvanizing, which earlier years don't.
IF the price is low enough, then the car may be worth it. The '77 does have full galvanizing, which earlier years don't.
09-18-2006, 09:37 PM
#10
Team Owner
look in the back at the engine and you will see the engine cooling fan. look to the right and down where the fan shroud meets with the casing and you will see the engine number...
09-18-2006, 09:45 PM
#12
Team Owner
also look at the engine shroud if I reacall the different engine sizes had different shroud colours, not absolute of course, mine is orangy red and it is a 3.0l I think the 2.7l may have been green ! can anyone confirm this ?
09-19-2006, 05:06 AM
#14
Racer
Also write down the chassis VIN and use this site to confirm that it is correct
for the year and model. http://www.adelgigs.com/911vin%20numbers.shtml
Either a sub-pages of this site or somewhere else on the net is a site for
deciphering engine VIN's or just post here. Also try to google for what a
thermal reactor setup looks like versus a "backdated" exhaust setup or better
yet ask to see receipts for engine work or exhaust work done...
for the year and model. http://www.adelgigs.com/911vin%20numbers.shtml
Either a sub-pages of this site or somewhere else on the net is a site for
deciphering engine VIN's or just post here. Also try to google for what a
thermal reactor setup looks like versus a "backdated" exhaust setup or better
yet ask to see receipts for engine work or exhaust work done...