The plot thickens...
 

OKay...got the car to idle okay this morning...let it run for 20 minutes or so...but still had no power. I pulled a plug wire and got a zap so figured spark is okay. I crawled under the car and felt the left heat exchanger and it was COLD. The right one was hot as it should be. Anyone have advice? I'm gettin fuel and spark on both sides, although I haven't checked the spark plug while it's hooked up to the wires outside of the engine yet for fear of starting a fire.

You did put the rocker arms in on the left side? Just kidding! I would first check to make sure you have the left side spark plug wires in the right order on the distributor cap and that all the sparkplug wires/boots are well seated on the plugs and distributor cap. Cheers, Jim

Have you re-checked the timing of the left cam?

Try to adjust the ignition timing to where the engine runs strongets. If this is way of the where it should be, then I would have considered checking the cam timing once again.

you can check the plug wires by using a spare spark plug instead of removing the plug, that way the fuel is not being pumped out of the cylinder head. just remove the plug wire put in the spare, ground it and turn the ignition.

gary

Virus

do you understand what is happenign here? I believe you are not having a healthy combustion "event" on the left side. Its doing domething or it wouldnt run at all. but the combustion is going out a valve or happening at the wrong time. The explosion is not very strong or happening at such an odd time the the hot exahust gases are not going out the exhaust. That; I think, is the big picture. Now you just have to figure out how to get the explosion to happen when it is supposed to. Seems like it has to be the spark is at the wrong time or the valves are opening at the wrong time to make the above scenario possible. Are you able to take the left side valve covers off, rotate the motor and visualize that valves are opening at the proper time in the sequence? i.e. piston up, valves closed, compression (rotor in distributor points to that piston for spark), piston down intake opening gas/air in etc.?? Its ok if you cant I have known alot of car guys that didnt really grasp it. In fact when I did my first cam I didnt - what a mess.

Good luck. enjoy the challenge!!

If the timing was off, wouldn't it affect the whole engine(doesn't hurt to check though)?
"Cold" would indicate a total lack of combustion, not just incomplete. My guesses would be many bad plug wires, mixture settings way off, crimped fuel line/filter for that bank, or even a broken chain. What did you do before to get it to run? Double check the routings/conditions, spark, fuel, and valves. Good luck man!

Please use a spark tester next time-40,000 volts isn't too good for the heart muscle. It also doesn't help the ignition system by having that voltage backfeed into it. They look like a sparkplug with a clip on the outside you put to ground, turn over and watch the spark.
I watched a neighbor doing a power balance on a pickup truck by pulling each wire and checking for rpm drop(while running). There was this loud ticking and there's a spark arcing from his pant leg to the bumper. The same guy had cut open his hand on the fan blade a week before and wrapped duct tape around it. Definitly a learning experience.

double and triple check to make sure the plug wires are on the right cylinders.

...
 

Thanks for all the response! I am leaning towards the left cam being off. I'm out of time tonight but will inspect it first thing in the morning. This afternoon I pulled the spark plugs and switched them...same problem. The plug wires are in the right spots...definately. In fact, there is only one way they can go on because of their length, if you start with the shortest being number 1.

right...but are the other ends of the spark plugs in the right place on the dizzy cap???

double check that...

good luck...glad to hear you are pluggin away...

Plug wires...
 

Yes, I have double and triple checked the order of the spark plug wires to the dizzy...as per the Haynes book: 1,6,2,4,3,5 going clockwise from #1. I'm going to check the chain tensioner today and make sure it's got full tension on the chain and check to make sure it hasn't jumped a tooth on the cam sprocket.

Will keep you posted...

In another post didn't you mention that you had a bunch of fuel in the air box? This would support the theory that the left cam is not properly timed and the intake valves on the left side cylinders are open on the compression stroke and atomized fuel is being forced back thru the CIS into the airbox.

this doesn't make sense. when you say "idle" i can just imagine idle means thumping as it has to be idling really really rough for only half of the engine running? sure it isn't one of those new caddy motors that cut out on the highway? (just kiddin')

The engine can indeed run on 3-cylinders - not well, but it can run. How's the #1 spark with respect to the TDC Z1 mark on the pulley? Is it firing at TDC (or near it)? Check this first. Do it also for number 4 (should be the same timing mark).

If everything is good, then your cam timing is most likely off. You're lucky you haven't bent valves (perhaps you have, and don't know it).

-Wayne

I had this problem after I had the injectors cleaned and put my MSD unit on. I thisnk I was running on two or three, can't remember exactly. Anyway I put new plugs in and bam everything was fine. I had overgapped the plugs and some of them fouled out. I read that you swiitched some of them but did you switch the "right" ones? I would put a new set in and try it before I dug too deep.

I don't know the history of the car in question. What kind of induction does it have? Any chance that it just isn't getting any fuel?

Wayne

Could you have timed both the left and right cams the same (both intakes opening on the same stroke)? This could make it run on three cylinders.

Tim

It's over.
 

Okay. I guess my so-called Porsche mechanic was just a wanna be VW mechanic. All the left side rockers arms have broken, and I can only assume it's due to bad cam timing. See picture. This project has now been terminated until further notice. One can only imagine what the valves look like if the rocker arms have been destroyed. I've spent over $3000 in this motor so far and am quickly learning that I could have bought a completely rebuilt 2.7 for that. Anybody know what a '74 roller is worth?

Yikes! You would have been better off if the mechanic had left them out! :( Jim

If the mechanic timed the camshafts I would go back to him and present him the bill to replace all the valves on that bank.

If I remember correctly you rebuilt this engine already. If so you should be able to get by by replacing just the valves. Not cheap but still not overly expensive.

I feel for you buddy and second the motion of going back to the mechanic who did the timing. Try talking to him about paying for the repair but if that doesn't work then you might want to look into your legal options.

Good luck.

...
 

Well, the mechanic who did the cam timing didn't charge me any money for doing it. It was kind of a favor for a friend type of deal. Apparently this car isn't worth dick, so I'm just going to keep it and fix the engine as time allows. However, I have lots of allen tools, but nothing that will fit in the small space to get the rocker screws out. Does anyone have a good source for these and know the exact size I need?

Sorry to hear about that KC. I thought you almost had her up and running again. Wasn't this mechanic a buddy of yours (trying to remember from previous posts)

When my car lost the tensioner, 3 of the rocker arms broke. But there was no other damage. Do a compression test( with all rockers removed on that side), that will tell you if correct cam adjustment and new rockers will fix it.

DOH! I'm sorry to hear that KC. I hope things get better from here

Virus,
Are you aware that you now need to pull this motor back apart? You can't half-ass it any more- chalk the lost $$$ thus far to (insert adjective & noun here, if I do it I'll get yelled at). Then start reading up, and start rebuilding on a more relaxed schedule, so you can get it right this time.

You appear to have other hobbies in which you are successful, take the lessons you've learned there and bring 'em to your 911 motor. You can do this.

WAIT! Broken rockers are a *GOOD* sign (well, relatively). It's like coming back to your house and finding that you had a small fire that put itself out. The local area is damaged, but not the entire engine.

Porsche originally made the rockers using a forging process. This made them very strong. However, when people started to have tensioner failures, the valves would bent (they were the weakest link gbye). Anyways, they redesigned the rockers to make them weaker so that they would break instead of the valves bending. Rockers are very easy to replace and don't require the engine to be rebuilt!

You also may be really, really lucky, as the CIS pistons, when they hit the valves, they have a tendency to bent the valves, regardless of the rockers (due to their funky geometry). If all you have are broken rockers, consider yourself very lucky.

Wow, I just looked at my previous post, and I pegged it right on! Whoo Hoo!

-Wayne

update...
 

I just took the lower valve cover off, and the lower rockers are broken just like the uppers. I have a feeling that the chain tensioner lost pressure at some point and allowed the cam to become "off" for one fatal moment. If I do a compression test and it shows 120psi like the rest of them...is it possible to replace the rockers with the engine in the car? I've found the right 5 and 8mm allen tools, but am having a hard time getting the shafts out with the engine still in the car.

As far as removing the engine and starting over...it will be some time before that happens. My kid is really sick so the wife and I have been taking turns being home from work, and as soon as he's better, I'll be working a lot of extra hours to make up for lost time and to just get out of the house.

Hell, maybe I'll just leave the rockers out and drive around on 3 cylinders :) JK!

hey

well you're getting there...

as for rockers...they are not horribly expensive, and you can find some used ones...

to get the allen bolts out get a 8 and 5mm wrench...and use a dremel tool with one of those cutting disks to shorten one of the arms...then they will fit in the tight spaces...

taking them out with the engine in the car is possible...but you may need to be a bit of a contortionist...or a partial engine drop may give you some more breathing room...the exhaust probably will not be a problem with the engine in the car

hope things work out...

I thik if you wanted to sell your engine you can probably get in the 2K or under range

and for the chassis...I've seen SC chassis go for about 4K...

hope things work out

MJ

I'll send you as many rockers as you need, in good shape, if you promise to take as much time as is necessary to do it right if your valves got whacked. PM for details, my rockers seem to have multiplied and I've got extras.

KC,

I think you should really take dtw's advice here. I think at this point if you get away with only the broken rockers you should be extremely happy. I know you said you don't have any time to work on the car right now. That might actually be a good thing, you should take it in steps. I would drop the engine, and fix what needs to be done without rushing. So what if it takes you three months.

Don't worry you will have this car running by summer. And I can't wait to read the title of the post when you go for your first drive. :D

Like I said,
Take your time.

I'm sorry about your misfortune, but from the other posts it appears that you may be "lucky" that the rockers broke. I hope you get it sorted, and that your son gets well soon.

I am wondering how does one know when these rocker shafts are tight enough when you replace them? How tight should one go with the two allens? I once had a small oil leak past #6 exhaust rocker shaft, but of course it is impossible to get in there with a torque wrench. I just tightened the offending expanding bolt a little, about 1/16 turn if I had to guess. Is it possible to overtighten them this way? dtw, Superman, JW, anybody?

LeRoux

I know this sounds way unscientific

but what I did was put my torque wrench on one of the engine/tranny nuts and I measured along the wrench shaft the length of the allen wrnech...so I'd pull on the t-wrench to the desired torque value (at the length I measured) then I'd try to replicate that feeling with the allen...

but in layman's terms I pretty much tightened them damn tight

not the best way but I could think of a way to get a wrench in there...

Do a Leak down test not a compression test, You will need to have the valve train in working order to get a correct compression test. A Leak down you just need to have both valves on there seats, And that is what you have with no rockers, Unless they are bent. Just my 02

Dude I am so wrecked. I thought you had it. Run some air into the spark plug holes and see if it is hissing out of exh. or air box. I wish I was closer to help.

rockers...
 

DTW...I'll take 'em...can you send them overnight??? Just kidding. Sent you a PM already. That would be great if you could send me a six pack of them and tell me how much to send. My email is kcmoore@sunflower.com

I have some rockers as well....I am sure you misread the cam timing articles. Once you do bank 1-3, you should follow the procedure for how you check/adjust bank 4-6. I don't recall off hand but I think after you set cylinder 1 you put your gauge on Cylinder 4 and rotate 360, it should be a 1mm or whatever your cam is spec'd at. I had mine 180 out and ran on three cylinder....but I was lucky...no damage.

once you get it timed and ready to go...three things are a MUST: 1. timing light 2. Pressure gauge for fuel pressure....3. A CO. analyzer....

This way your not guessing and having a damn headache chasing your BUTT....these are all items within anyones budget.

Recheck your timing. This can be done with the engine in the car. Also, I *seriously* doubt that your chain tensioners caused this failure. It's very unlikely. I have never heard of three rockers getting broken because of that. I think that the only answer is that you're timing is way off. This is one reason I tell people to spin the engine with a wrench prior to starting it up...

-Wayne

update...
 

DTW...thanks for the offer...got some rockers locally...thanks so much for the offer!

I will be fitting the new rockers probably this weekend. I did another compression test on the left side, and it's still showing 120psi, and I can push the valves in and out a little against the spring, so they're showing movement.

Guys, I turned this engine over probably 100 times by hand prior to starting, and it had absolutely NO resistance. Is it possible to have the left cam off 180 degrees and still have the valves stay clear of the pistons? If so, I'm thinking that's what happened. Unless it's not possible to have set the cam timing to spec. and still be 180 off?

I mean, is it possible, with dial indicator and all, to have set the left cam to the right specs, but have it 180 or 360 off? Perhaps, even having it set exactly the same as the right side and not realizing it? But if it were set that way, would it even turn over?

yes i did that!!!! 4-6 bank headers were cold when running