Rod Knock???

enzof · 03-04-2006, 02:53 PM

Can someone explain what a rod knock is? Can it be fixed easily and cheaply? Would you purchase a vehicle that has a rod knock?

Grady Clay · 03-04-2006, 03:11 PM

Enzof,

WELCOME to the Forum.

What car are you considering (year, model, configuration, mileage, condition)?

Why do you say “rod knock”?

A rod knock is the audible symptom of a failed connecting rod bearing failure. Big deal and expensive problem. Fortunately fairly unusual for a 911 engine. If this is the problem, it takes a complete (expensive) engine repair.

Exactly what are the symptoms and conditions (rpm, temperature, acceleration, load)?

Has anyone done a definitive diagnostic? I can’t tell you the number of times someone (non-Porsche) diagnosed a failed chain tensioner as a rod knock.

To answer your question; yes, I would buy a 911 with a rod knock – if the price and condition were right.

You will get really good advice on this Forum. You can help by presenting as much info as possible.

Best,
Grady

enzof · 03-04-2006, 03:24 PM

Its a 1978 911 SC with 160,000 miles. The condition of the vehilce is poor.

jerhic · 03-04-2006, 03:58 PM

rod knock is bad news. what does the oil pressure look like when the vehicle is at operating temperature and at idle ,and say at 3000 rpm? if you have good oil pressure you might look else where for your noise. if you do have a rod making noise you will have to open the engine and repair the problem. this could be $$$.

Jack Olsen · 03-04-2006, 05:06 PM

Snapped head studs left unaddressed will eventually produce some interesting sounds.

Grady Clay · 03-04-2006, 08:32 PM

Enzof,

Tell us more about your goals and skills. Do you want a “project” and are willing to DIY an engine repair and more? Do you want a nice 911 to drive or track and are looking for a bargain (like all)?

When you say “condition poor” what exactly do you mean? There are some cars that need so much expensive attention they aren’t worth accepting for free. I looked at a similar 911 last year that was just wonderful – original paint, provenance, nice leather, etc. but to bring all the systems back to proper performance (had broken head stud, very marginal syncros, poor clutch, needed heat exchangers, shocks, brakes, CVs and much much more) would cost double what the 911 would be worth. My heart wanted to do it, my common sense said no. If it were given to me I might have attempted the rejuvenation but I wasn’t about to offend the owner with such an offer. I passed.

The best long term bargain is to buy the absolute best condition 911 within your budget and maintain it at that level and better. If you want a “project,” find a special 911 with provenance and have a 5-20-year fun effort.

Best,
Grady

enzof · 03-05-2006, 04:36 AM

My skills are very limited when it comes to cars, so a DIY engine repair would be out of the question.
I love Porsche's and have purchased new Porsche's in the past. I just find the fun of a new purchase wears out quickly. I am looking for a "project" car that I can take my time and learn how to restore it to my likes and specs. Some of the work I would do myself, but the more complicated work I would send out. As for the $$$. This is not a investment and I am fully aware of whatever I purchase I will never get my money or time back....but thats the whole point. I think I would appreciate the car knowing that I did all(most) of the work.