2.7l engine problems?

[cfletch13]

Thinking of purchasing a 1974 2.7l engine and am curious about what makes these engines so caustic? everywhere i read i hear about how they were troubled engines ,but with no actual reasoning to justify. Can anyone shed some light onto the subject for me? -Colin

[Mike Czech]

Colin,

Do a search on Pelican and you'll find a lot. Basically, the '74-'77 2.7l engines had the following issues, mostly related to running too hot:

1. Heat exchangers that make the underside of the case too hot. This can cause differential expansion of heads/cylinders and head studs and sometimes leads to pulling of head studs. This can be fixed with dilivar head steads which expand at the appropriate rates. (Do a search for "2.7 and dilivar" and you'll find a lot of info).
2. 5-blade fan. Some say it doesn't flow enough volume of air to cool the engine. This can be replaced with an 11-blade fan.
3. Cam chain tensioners are mechanical and can fail. If you replace with hydraulic tensioners, the problem is fixed.

I've got a '77 2.7l 911S and love it. All the 2.7l issues have been addressed and mine runs like a rocket and I don't have any issues. There has been a recent thread regarding the 2.7l motors and how option has changed here: Funny how nobody trash talks the 2.7 anymore

- Mike

[Slush]

Don't get too hung up in the engine model. If you're looking at a specific car, the issue isn't whether it's a 2.4, 2.7, 3.0 or whatever. The real issue is the actual engine itself.

What's the status of it? Has it had a top end job done or a complete rebuild? And when was it?

The best thing you can do is a proper PPI with a leak down test and a compression test. That will tell you most you need to know.

I've been the very happy owner of one of those lovely rev-happy 2.7s for 3 years. If they're well-maintained they're nothing but bundles of joy.

[74-911]

Originally Posted by Mike Czech

1. Heat exchangers that make the underside of the case too hot. This can cause differential expansion of heads/cylinders and head studs and sometimes leads to pulling of head studs. This can be fixed with dilivar head steads which expand at the appropriate rates. (Do a search for "2.7 and dilivar" and you'll find a lot of info).
2. 5-blade fan. Some say it doesn't flow enough volume of air to cool the engine. This can be replaced with an 11-blade fan.
3. Cam chain tensioners are mechanical and can fail. If you replace with hydraulic tensioners, the problem is fixed.

Please note: '74's do not have thermal reactor heat exchangers or the 5 bladed fan and are much less susceptible to heat issues. Dilivar studs present other issues.

Slush gives excellent advice. Many 2.7s have been rebuilt completely or had top end work to replace the valve guides. Find out what has been done to the engine by the POs, have a good PPI with leakdown and compression testing.

If the '74 you are looking has had a good external oil cooler under the passenger side front fender, chances are it may not have any heat related issues. I think this was one of the main causes of 2.7 heat issues - lack of an external oil cooler completely or just the trombone cooler which did little to help.

the 2.7 in my 74 was rebuilt over 25 years ago (due to value guide failure) and is still going strong.

[cfletch13]

Thanks for the info from all of you. Im actually not buying a 911 with this engine. I'm thinking of getting one of these and throwing it into my 70' 914 (i know). The owner of the engine claims its been rebuilt and everything squared away except for the chain tensioner upgrade. But I do wanna be sure im not spending money on a paperweight thats gunna cost me more to fix later on.

[Driver_X]

Fwiw hydraulic chain tensioners fail too. The only truly "fail proof" method is the mechanical tensioners with safety collars. That way, when they fail they only go so far, preventing major damage. Plenty of info on this debate on the forums as well....