The plot thickens... - Page 2

porsche_virus · porsche_virus's Garage

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?

crashr · 02-11-2003, 06:40 PM

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)

69911e · 02-11-2003, 07:16 PM

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.

Tim Walsh · Tim Walsh's Garage

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

dtw · 02-11-2003, 08:04 PM

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.

Wayne 962 · Wayne 962's Garage

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Porsche originally made the rockers using a forging process.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

porsche_virus · porsche_virus's Garage

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!

82SC · 02-11-2003, 08:57 PM

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

dtw · 02-11-2003, 09:01 PM

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.

crashr · 02-11-2003, 09:45 PM

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.

Like I said,
Take your time.

LeRoux Strydom · 02-12-2003, 02:11 AM

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

82SC · 02-12-2003, 02:15 AM

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...

gregk1 · 02-12-2003, 07:39 AM

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

Elombard · 02-12-2003, 09:35 AM

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.

porsche_virus · porsche_virus's Garage

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

Jbabic · Jbabic's Garage

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.

Jbabic · Jbabic's Garage

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.

Wayne 962 · Wayne 962's Garage

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

porsche_virus · porsche_virus's Garage

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?

Jbabic · Jbabic's Garage

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