914 1.7 Knocking Sound -- New Here, First Post, Horrible knocking coming from the motor Options

[UberElectricEagle]

Greetings. I am new to the Porsche world and I purchased a 1972 914 1.7 about a month ago. It's a pretty nice car over all, but I think the motor, or part of the motor, might be toast.

When I purchased it, it badly needed a muffler. The knocking noise was harder to notice and sounded more like an exhaust leak over the horrible sound of the lack of a working muffler. The car seemed to run decent even with the poor exhaust and the price was good so I bought it. I just wanted a decent car over all that I could drive around for fun on sunny days before the winter gets here. It came with stainless heat exchangers I installed and I installed a really nice dual muffler from Dave at Triad.

When I fired it up with the new muffler, I really noticed the knocking when I drove it since the all the exhaust leaks were now sealed up and I wasn't wearing ear plugs. At idle it's not too bad, but once I get going, the knocking is very noticeable. It's odd too, because it's not real consistent under power in motion.
To me it sounds like the noise is coming from the #1 cylinder. I think the cylinder is providing no power, because when I take the wire off the cap, there is really no change in performance. (I put a video link of the horrible sound below.)

Any advice on where to go from here would be great. My gut feeling is telling me the motor is going to have to come out. If I'm going to do all that, I might as well put a 2.0 liter in or ????? I'd even settle for just a solid running motor with some minor upgrades to make it a little quicker. Any advice on what route to take on a good used motor would be great. I guess A motor that runs on 4 cylinders would be an upgrade. Thanks for your help, a mildly depressed Sam

http://www.youtube.com/watch?v=a5JhEd7SUH4...re=channel_page

[VaccaRabite]

Hey Sam,

(IMG:style_emoticons/default/welcome.png) !!
Before you pull the motor, try and adjust the valves. It may be that the rocker arm has come off. It happens, and makes a clatter and the cylinder won't fire. If thats it, it is a simple fix, and will be very noticable when you go to adjust valves.

After valves are done, do compression test. (valves need to be right, throttle needs to be open). That will tell you if the cylinder is at least building compression.

if you have dropped a valve seat (zero compression on #1 is probably a dropped seat), it is rebuild time. At that point, source a 2.0, or rebuild the 1.7 into a 1911. (IMG:style_emoticons/default/smile.gif)

Zach

[x6in6flames6x]

(IMG:style_emoticons/default/welcome.png) nice to see another PNW teener. and zach pretty much summed it up. (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/beerchug.gif)

[Pat Garvey]

Hey Sam,

(IMG:style_emoticons/default/welcome.png) !!
Before you pull the motor, try and adjust the valves. It may be that the rocker arm has come off. It happens, and makes a clatter and the cylinder won't fire. If thats it, it is a simple fix, and will be very noticable when you go to adjust valves.

After valves are done, do compression test. (valves need to be right, throttle needs to be open). That will tell you if the cylinder is at least building compression.

if you have dropped a valve seat (zero compression on #1 is probably a dropped seat), it is rebuild time. At that point, source a 2.0, or rebuild the 1.7 into a 1911. (IMG:style_emoticons/default/smile.gif)

Zach

Beg to disagree!

The 1.7 is a rock solid motor. You aren't going to get a significant HP increase by zooming the motor.

BYW - to the owner - welcome to the mayhem! Those wheels are not proper for a '72.
Pat

[Rod]

welcome. Do a valve train check first. Shame the car has lost it's FI (IMG:style_emoticons/default/sad.gif)

I run a standard 1.7l with D-jet and it's a great little motor... Did 400 miles over the weekend and it ran as sweet as a nut. Yes 170hp would be nice, but it keeps up with modern traffic very easily..

Do you like the sound of the Triad?? (IMG:style_emoticons/default/biggrin.gif)

[type47]

BYW - to the owner - welcome to the mayhem! Those wheels are not proper for a '72.
Pat

(IMG:style_emoticons/default/popcorn[1].gif) (IMG:style_emoticons/default/driving.gif)

[underthetire]

I agree with Zach. Maybe roll the pushrods to check if one is bent ?

[Rand]

Hey Sam,

(IMG:style_emoticons/default/welcome.png) !!
Before you pull the motor, try and adjust the valves. It may be that the rocker arm has come off. It happens, and makes a clatter and the cylinder won't fire. If thats it, it is a simple fix, and will be very noticable when you go to adjust valves.

After valves are done, do compression test. (valves need to be right, throttle needs to be open). That will tell you if the cylinder is at least building compression.

if you have dropped a valve seat (zero compression on #1 is probably a dropped seat), it is rebuild time. At that point, source a 2.0, or rebuild the 1.7 into a 1911. (IMG:style_emoticons/default/smile.gif)

Zach

Beg to disagree!

The 1.7 is a rock solid motor. You aren't going to get a significant HP increase by zooming the motor.

BYW - to the owner - welcome to the mayhem! Those wheels are not proper for a '72.
Pat

Huh? I don't get the disagreement. First have to find out if this 1.7 is rock solid or not. It would be great to find a valve train problem that could be fixed without having to tear the motor all the way down. If you do have to rebuild it then choose your build based on the level of performance/economy you want. A 1.7 with FI is a sweet economical package. Carbed with a stock cam, not so much. A strong 2.0+ is a lot more fun.

Those are the most-desired 4-lug wheels. The only way they are improper is if you are being judged on a concourse. The other 99.9% of people will appreciate your Fuchs.

Welcome. Hang in there and cross your bridges one at a time.

[UberElectricEagle]

Hey Sam,
(IMG:style_emoticons/default/welcome.png) !!
Before you pull the motor, try and adjust the valves. It may be that the rocker arm has come off. It happens, and makes a clatter and the cylinder won't fire. If thats it, it is a simple fix, and will be very noticable when you go to adjust valves.

After valves are done, do compression test. (valves need to be right, throttle needs to be open). That will tell you if the cylinder is at least building compression.

if you have dropped a valve seat (zero compression on #1 is probably a dropped seat), it is rebuild time. At that point, source a 2.0, or rebuild the 1.7 into a 1911. (IMG:style_emoticons/default/smile.gif)

Zach

Thanks for the help. I'll give it a look and see what's going on under the valve cover. I hope it is fixable. I just want to drive the car for now and use all 4 cylinders.
If the motor does come out; I think something faster will go back in because The car is not completely stock anyway.
Sam

[UberElectricEagle]

Beg to disagree!

The 1.7 is a rock solid motor. You aren't going to get a significant HP increase by zooming the motor.

BYW - to the owner - welcome to the mayhem! Those wheels are not proper for a '72.
Pat

Thanks for the welcome. I'd be happy with the 1.7 if it was running on all 4, but it's not. If it's fixable, it will stay in as is.
There are several things on and in the car that are not stock for the year. I really like those wheels on the car and They are very light too.
Sam

[UberElectricEagle]

welcome. Do a valve train check first. Shame the car has lost it's FI (IMG:style_emoticons/default/sad.gif)

I run a standard 1.7l with D-jet and it's a great little motor... Did 400 miles over the weekend and it ran as sweet as a nut. Yes 170hp would be nice, but it keeps up with modern traffic very easily..

Do you like the sound of the Triad?? (IMG:style_emoticons/default/biggrin.gif)

Thanks. I too was sad the fuel injection car was gone, but was happy to see two carbs instead of one. (probably does not need dual carbs)
I was real pleased it has 5 speeds and does great on the freeway even on 3 cylinders. I'm surprised it runs as well as it does even with the malfunction. I know I'll be much more pleased with 4 fully functioning cylinders.

I do like the sound of the Triad and I like how it looks too. I just wish I could hear it with a healthy motor because I think it will sound even better. It's built really well and I'd recommend one if you are looking for louder than stock. It's a good price for the quality.

[Cupomeat]

If you like the wheels, keep them as they are the right offset and look great on that car.

I agree with Zach about checking the valve train first, especially if I hear it right and the knock is not every rotation of the engine, but about every other, which points to the valve train.

Pull the covers, see if everything is in place and the rocker shafts are tight to the heads, that the adjustment screws are in place, and that none of the rockers has enormous play in them.

Then report your finding, including a picture, as it keeps people interested and there will be lots of help.

Certainly, you could have a real engine threatening problem, but let's do the easy stuff first.

Good luck and I hope this helps.

[UberElectricEagle]

Huh? I don't get the disagreement. First have to find out if this 1.7 is rock solid or not. It would be great to find a valve train problem that could be fixed without having to tear the motor all the way down. If you do have to rebuild it then choose your build based on the level of performance/economy you want. A 1.7 with FI is a sweet economical package. Carbed with a stock cam, not so much. A strong 2.0+ is a lot more fun.

Those are the most-desired 4-lug wheels. The only way they are improper is if you are being judged on a concourse. The other 99.9% of people will appreciate your Fuchs.

Welcome. Hang in there and cross your bridges one at a time.

Thanks for the encouragement. I don't know first hand, but I just seem to think a bigger motor would be more fun too. I'm not looking for fuel economy or a quiet ride. I have regular cars for that stuff.

I really like the Fuchs too and was happy they were on the car. If it didn't have them already, I'd go find some and buy them.

[Cupomeat]

Just one more thing of encouragement, that doesn't sound like the "BAD" sounds that I've heard.

Last DE I was in at Watkins Glen, I guy came off the track spewing oil in his recent top end rebuilt 3.2 (911) and that engine was just destroying itself.

We tried to get him to let us push it on the trailer, but he wanted to drive it up.

It was as if we were just throwing hundred dollar bills into the intake for the damage it was doing. Probably was throwing bits of a piston around in there...

he would have saved thousands of dollars if he had just killed the motor while on the track and let the tow truck pull him in.

The worst noise I've ever heard on a motor. I've heard ones like yours before and they survived. Of course, this is all from an youtube clip so...

[VaccaRabite]

Hah! I did not even see the youtube clip.

Anyway, that sounds a lot like my motor sounded when the rocker arm backed off the studs. Scared the living daylights out of me at the time. Took about 15 minutes to fix - its just two nuts.

Check your valve train fo-sho! I'm sending you positive waves!

(IMG:http://www.canadaka.net/modules/My_eGallery/gallery/funnypics/military/ODDBALL_SAYS.jpg)

(IMG:style_emoticons/default/driving.gif)
Zach

[ME733]

(IMG:style_emoticons/default/popcorn[1].gif) First things FIRST....BASIC THINGS FIRST...."I pulled the wire out of the distributor cap....and there was no change". (in the dead cylinder). CHECK THE SPARK PLUG WIRE for continuity. (does electricy flow through it, and the spark plug connector , and connector that inserts into the CAP....= good or bad., bad = replace ALL of them. Good = go to spark plug next. remove and inspect, , oiled = missfiring, (can also have gas smell=misfiring). BAD = replace all spark plugs. be sure to gap them properly. Note ; there are replacement spark plug wire sets out there, that are of the suppression type. these are carbon impregnated, coated, (nylon, fabric, or some such). THEY are great for radio static suppression. BUT THEY will break internally. causes obviously, misfires or dead spark plugs. The noise may be from ..THAT particular Piston not being hot and ratteling in the cylinder. After these basic things well...Post.. what you do and discover. (IMG:style_emoticons/default/popcorn[1].gif)

[ME733]

(IMG:style_emoticons/default/popcorn[1].gif) One ADDITIONAL THOUGHT...whenever you purchase any car with a "bad muffler"...just assume the owner is intentionally masking an engine problem. it,s a very old con/trick. you will also find the price is really good almost too good to be true. Pass it by, or FACTOR into the price and value a replacement engine. (IMG:style_emoticons/default/popcorn[1].gif)

[r_towle]

valve train
tune up
carbs adjusted

[Cupomeat]

Any update?, Inquiring minds WANT to know!

[UberElectricEagle]

Any update?, Inquiring minds WANT to know!

I'm just getting started right now. Had to work last night until 5am.
Hoping for fixable.