Engine gurus, please help!!!!
 

So I started my car the other day (1974 911) and noticed that I lost power. The engine starts as usual, but it sounds a bit different. I'm hoping the problem is the spark plug wires (because oil pressure is still the same as before) Does my logic make sense? If not, can anyone recommend a good, an honest, mechanic near Glendale, CA.

You guys have always come thru for me, and look forward to the dispensation of wisdom that surely will follow.

Talk to Dave at TRE in N. Hollywood. He can steer you correctly and is close.

TRE Motorsports, Inc.
TRE Automotive
11046 Chandler Blvd.
N. Hollywood CA 91601-3226
(818) 509-0257
Fax: (818) 509-2638
www.tremotorsports.com
info@tremotorsports.com
Dave Bouzaglou, President, CEO
daveb@tremotorsports.com

Map HERE


There are a lot of things it could be. More info will help.

Did this change occur suddenly or gradually? Were there any other occurrences simultaneous with the change? You said it was after starting, was there a backfire? Does your CIS have a pop-off valve? If so, have you checked its sealing?

With the engine at idle are there any unusual mechanical noises? Does it sound like it is running on all six cylinders? Is there a difference between the normal running and idle? As a test, lift/push on the air filter assembly and note any change in idle.

There might be a simple fix but I’ll give you the worst case first.
The head to cylinder sealing could have failed from a pulled cylinder head stud.
The cam could have jumped time on one side from a failed chain ramp.
And more.

The easiest is there was an intake backfire and the aftermarket pop-off valve didn’t re-seal correctly.

Of course there are all sorts of intermediate possible issues, some very inexpensive and some at the other extreme.

This Forum can possibly help you diagnose the problem. An hour or so at TRE will either fix the problem or give you the necessary diagnostic information to make informed decisions.

Best,
Grady


EDIT - I can't get the vB code to produce the proper links, what is the deal?
G.

74SilverBullet,
You have the attention of a "Guru". Just give him more information, and watch what happens...

what nine9six said..i started to say something, but why bother!
ryan

Thank you very much for the response. The problem happened suddenly. The car was driving perfectly the day before. It has been raining quite a bit and the car sits outside, thus I was thinking that something may have gotten wet (a cable or something)

The car does feel as if it's running on 5 cylinders, I can definitely tell that some power was lost.

Thank you again for your input and I will definitely talk to the folks at TRE.

Obed

Oh yeah, I forgot, the CIS does have a pop off valve and when I checked it it looked fine. I recently re-sealed it because it was sucking in air and the car would not start.
Thanks again to everyone.

I still would re-check the pop-off valve. A little silicone grease on the seal also helps.

What results from pull/push on the air filter assembly?

With it feeling like it is on 5-cylinders, have you looked inside the distributor cap, inspected the plug connectors & wires and checked the spark plugs? The goal here is to identify a possibly dead cylinder. It can also be a fuel issue.


Guys, chill – question authority.

I make at least one significant mistake a month. If it weren’t for other more knowledgeable Pelicans that mistake might be accepted as fact and I don’t want that on my back. This is why the internet is so untrustworthy and Pelican has this wonderful reputation. No one will ever offend me by questioning something I have posted. In fact some of the best info comes from arguing some point. There is no such thing as a “dumb question” here, I ask many. Please “bother” and have a discussion. I hope I have never offended anyone. Honest disagreements are wonderful.

Best,
Grady

i promise to try and chill..'big'..! :p
ryan

Grady, Bigchill, and nine9six,
Thank you so very much for lending a hand.

Grady, what I will do is replace the sparkplugs and wires and see if that does it (it is relatively inexpensive). I looked at the distributor cap yesterday and it looked good (no cracks or burnt spots)

If that does not do it I think I'll just find a dark corner and curl myself into a little ball, because I already replaced this engine not too long ago....

Y

74sb,
another wise move would be to 'baseline' a couple of other parameters: check your points gap with a gapping tool and dwell meter and also check static and dynamic timing with a timing light. if your engine is stock '74, like mine, then you have a vacuum 'retard', rather than advance mechanism. i'd do these after confirming continuity with your plug wires, properly gapped plugs, etc.
ryan

It's been a long time since I owned the '77 Targa. Sold it in '96. But, I have read here that wet plug wires are not a good thing if they are the shielded kind. I had a bit of trouble during the wet weather and never allowed the car to sit outside or the motor to get serioulsy wet during washing. Seemed to help.

Ryan and Zeke,

Thanks...I really hope that the problem is the spark plug wires, as they did get pretty wet from all the rain. I'm not as mechanically savvy as I'd like to be, thus some of the recommendations made here are beyond my technical skills...

Semper fi,

I make at least one significant mistake a month. * * * No one will ever offend me by questioning something I have posted.
_______________________

- I question the error rate -- I think it is much lower.

ditto as a first step