Never ending problem for the 13th engine rebuild (very long post)......
 

HI am not superstitious but the current engine rebuild project has taken me to my knees and begging for help. Prior to this engine rebuild, I have successfully done more than a dozen engine rebuilds with no major problems at all. Here are the series......

11th rebuild..........completed, tested, and delivered.
12th rebuild..........partially done and put aside. This is my son's engine.
13th rebuild..........completed, tested, and delivered. This was a twin plugged, crank fired with individual throttle body fuel injection system at 10.3 CR.
14th rebuild..........this is actually the 13th that I am trying to finish and complete.
15th rebuild..........awaiting in the garage.
16th rebuild..........awaiting in the garage.

While I had successfully rebuild several engines in the past, I am not an expert by any means at all. Just an avid engine rebuilder and enjoying the successes through the help of other members like Bruce Abbott and a few others.

Background:

A PP member contacted me in 2014 to rebuild his 3.0 liter engine which two professional shops failed to do. The engine was delivered to me in several boxes and started sorting the engine parts. It was in the fall of 2015 that I started rebuilding the engine up to winter and was temporarily delayed when my wife and I traveled abroad from January to March (2015).

As soon as I got back home, the rebuild was initiated for the start up. It was in April 2015 that I began the engine start up. Right away, a noticeable problem was observed. Heavy oil leak was leaking from the flywheel end. Engine removed from the engine test stand and inspected the source of the problem. Wow!!!! What a stupid mistake I had committed. There was no flywheel oil seal installed. Corrected the problem and the engine is dry as it could be.

Engine installed back on the test stand for start up. It was almost end of April 2015 but have a month before Memorial Day. This was the first target date of completion. June 2015 came and still no luck getting the engine to even start or idle. July 4th passed with no progress!!!! Very frustrating and disappointing. It took me a few hours to test and run the fully rebuild engine/s in the past. But this particular motor refused to cooperate at all. After Labor Day, after months of trouble shooting, I discovered the problem for the fuel pump caused by a wiring anomaly. The engine wire harness was new from Timmy2. Contacted Dennis P. about the wiring problem of his wire harness. Initially he did not believe it was the culprit. And I explained to him why it was the culprit. The engine wire harness is a piece of art. Well designed and built but has a flaw which I believe Dennis has corrected.

Now that I could make the FP run and the CSV with correction to the wire harness, the engine still refuse to start. The CIS unit was removed four (4) times and tested. No vacuum leak. A clogged fuel injector line was replaced, and a newly rebuilt FD installed too. Still no fuel was coming from the injectors (?). The engine was not sucking air to create vacuum. The cams were inspected and discovered another mistake committed. The 964 cams were installed at the wrong side. What a blunder! I know which cam goes to the left or right, but when I installed them I inadvertently placed them at the wrong side of the engine. I had a senior moment to remember which is the left or right side of the engine. All the rockers were removed and cams switched.

Tests have demonstrated that the engine was creating suction from the intake manifolds. Installed the CIS unit back on the engine. FP running, injectors delivering fuel during manual tests, FD good, but no fuel delivery during cranking. This was a very discouraging time. I was hoping to finish this project by Thanksgiving Day and still have time to do it. But I have to solve the fuel delivery problem. After many hours of investigation, I discovered the problem. It was the aluminum elbow connected to the CIS. The elbow connector was removed and replaced with the correct one. Lo and behold, I got the fuel coming out of from the 7 injectors during cranking for the first time. It has been several months of work and finally got to the point where I could run the engine. I was ecstatic and jubilant. I was happy and celebrating for the success.

The celebration was short lived! I heard an abnormal sound like metal breaking apart. Found out that the exhaust rocker for cylinder 6th was broken. Further inspection showed bent valves (see my post about bent valves). And the engine won't turn more than 180 degrees and some sort of obstruction was causing it. The piston was hitting the valve/s as far as I could tell that required partial engine disassembly for the nth time.

To remove #6 cylinder, I have to remove the cam, rockers, cam tower, etc. Found a nut causing damage. Cylinder head was brought back to Atlantic Anchor for repair. Got the repaired head within 2 days. Bob Hirst was real helpful to work and have it done at a very short notice. Bruce Abbott kindly supplied me a couple of good rockers.

The weather was so cold to work outside last month (January). I don't have a heated garage so I decided to bring the motor inside my house and deliver it back at my basement. With a warm basement, I should be able to spend more time and finish the project. So I planned to bring the motor inside the house after my birthday on January 23. You know what happened on my birthday? A snow storm with 2 feet of snow buried my backyard. The ramps and dolly that I use to transport the engine inside my house were under more than 2 feet of snow and ice. Spent my 73rd. birthday doing snow removal for the whole day and was exhausted. Too much physical work for an old guy like me. This was another setback and won't stop me from finishing this project before Super Bowl Day. But my wife was not happy to see me working in my unheated garage with bone chilling temperature.

To my surprise, she asked me how much time I needed to finish the engine. I explained to her that I was planning to bring the motor inside the house and bring it back to the basement to work on it. Two weeks should be sufficient and it was almost end of January. But the ramps were buried in snow and it would take weeks to get the snow to thaw. My wife felt my disappointment and failure to get this motor finished. She voluntarily offered to me to use the kitchen for two weeks and bring the motor out before February 7.

In short, I was allowed to bring the engine and engine stand into the kitchen. My wife hates the odor of gasoline and oil. So to overcome this problem, she is running an electric deodorizer to mask the odor of the engine oil. I was able to assemble and complete the engine before the Super Bowl Day.

Cam timing, valve adjustments, sprocket alignment, etc. completed. However, I noticed something very peculiar. When you turn the crankshaft 360 degrees, it goes around with no impediment. Turned the crankshaft so many times and no restriction. But why is there a slapping noise from the engine at 120 deg. intervals? Another annoying problem? Here is a description of the problem when you rotate the crankshaft.

@ TDC Z1............a slapping noise of the cam/valve occurs between cylinder #1 going to cylinder #6. It is about 1/3 between #1 and #6 markers on the crank pulley.

Cylinder #6.........a similar slapping noise occurs between #6 to #2. Same as before, 1/3 distance to cylinder #2.

Cylinder #2.........same as above.

Cylinder #4.........same as above.

Cylinder #3......... same as above.

Cylinder #5..........Same as above.

The slapping noise occurs consistently at a 120 deg. sequence. The cams and rockers were abundantly lubricated.

Anyone had encountered this problem before? Any suggestion or recommendation welcome. This was not observed before, so there is something very wrong that I have obviously overlooked. I will post additional pictures. Thanks.

Tony

When you realized the cams were installed incorrectly, did you completely disassemble the engine and inspect all components for damage?

Rotating the engine with the cams installed in the wrong banks, can cause significant damage particularly with a high lift cam.

Hmm, I'd start by removing rockers from #6 and see if pattern changes.

Tony

I can't imagine what's causing the slapping sound. 1/3 from TDC you get the sound, every 120 degrees of rotation?

If I think about it, 1/3 from 1 going to 6 is where 2&5 are getting very close to BTDC. They have not yet bottomed out, but are getting close to getting pushed upwards. 1&4 are really just starting to go down because the dwell at TDC as the crank journal reaches the "top" and has started to pull the piston down. 6&3 are halfway up. Could the rods be loose? Pistons loose in the bores?

I sketched the valve opening and closing on a circular graph and it would seem you are far away from valves getting close to the pistons. But maybe it's possible?

I have to ask, why didn't the other shops want to rebuild this engine? It seems very odd. And you've had some real misfortune with this build. Are you sure all of the parts were good to start with?


First, I'd pull the plugs and shine a bright led light into the plug holes and look into the intake and exhaust ports to see if the valves are getting too close to the piston. You should be able to see the piston top quite easily. Then rotate the crank in small increments and look in all ports, keeping notes of what you see. That should answer the question on clearance.

My thoughts:

Cams spin at half engine speed so 720/6=120 so it would be in the timing not the crank/pistons.

Piston valve relief too small? Valves touching each other?

But I'm not really the right one to ask. I've got no experience.

Update for tonight........
 

My son came over the house to give me a hand and offer a set of second eyes and ears. As I turned the crankshaft (clockwise) starting @ TDC Z1 for cylinder #1 (1-6-2-4-3-5) sequence, my son was closely observing the movement of the cam and rocker arm for each cylinder. As anticipated, the slapping noise came as predicted at 1-6-2-4-3-6 sequence.

And a very close up observation at cam and rocker arm inter-action seems to show a sudden loss of contact between the cam lob and the rocker arm during engine rotation. This was the 3rd time the cam timing was set. The previous 2 times never had this slapping problem. So I will re-test the cam timing setting. Both sides were set @ 1.30 mm cam timing. Previous setting was @ 1.26 mm.

Please feel free to offer any ideas, suggestions, recommendations, etc. and will consider them. It is obvious that there is mechanically wrong or out of spec. that I do not realize at the moment. Thanks.

Tony

Good to hear your son is helping.

When you say a loss of contact between the rocker and the cam lobe, I am going to assume you mean, as the cam profile decreased, the valve stayed open, the rocker was loose, and then the valve closed some and took out some slack?

Please explain exactly what was happening verse what should have happened. Intake or exhaust? During opening or during closing?

My first thought is the valves are sticking in the guides, maybe?

Perhaps the tensioners are not pumped up. I hear a noise like that when turning over an engine by the pulley bolt while setting cam timing and adjusting valves sometimes. It has carrera tensioners, right?

Will evaluate sticking valve condition........
 

Mike,

We have been observing closely the left bank (1-2-3) and noticed the intake rocker arms making the noises during valve closing when the cam start to decrease in height. And you could observe a sudden movement of the intake rocker arm/s as it comes in contact with cam lob. My son's first reaction was that I might have the wrong valve springs.

But it never occurred to me about 'sticking valves'. Now that you mentioned it, I will focus on this problem. If sticking valves are the culprits, why it did not occur previously? So far, I am very interested and concerned about it. Will do further observation to evaluate 'sticking valve' phenomenon. Will keep you posted. Thanks.

Tony

Are the cylinders machined and the case spigots?

Sounds like valve to piston contact? Backing off all rockers, then spinning again might tell what's going on.

If there is still noise, wonder if the pistons are contacting the heads from question above?

Did you ever do a clearance test between valves and pistons?

Hydraulic tensioners.......
 

John,

I have the mechanical tensioners from Stromski installed. I've been using these tensioners for cam timing set up and never had any problem in the previous dozen engine rebuilds. They are still installed at the moment. And will be removed when I installed the Carrera hydraulic chain tensioners.

Could I remove the valve springs with the cam tower installed so I could test if the valves are sticking? Do you know the ID of this Porsche tool? BTW, this was the 3rd. time the cam timing was adjusted and set. The first 2 times there were no slapping or ticking noises when you rotate the crankshaft. This time after the 3rd. time to set the cam timing, you could hear the noise every 120 deg. travel of the crankshaft pulley.

I am trying to think very hard what I did differently this time compared to the previous cam timing jobs. I am listening to suggestions and comments from everyone. What would you do if you were in my shoes to resolve this problem? Thanks.

Tony

Standard 3.0 liter SC engine.......
 

Tippy,

The cylinders nor the crankcase was not machined. The first time the engine was assembled, the engine rotated 360 degrees without noise coming from the cam or valves areas. But the engine was partially disassembled when I discovered that the cam shafts were inadvertently installed at the wrong bank. Thus requiring another cam timing and valve adjustment job. Unfortunately, exhaust rocker #6 broke and bent the valves. Requiring another partial disassembly for the cylinder head removal and inspection.

Now, during the 3rd. cam timing job, I noticed the peculiar noise when I turned the crankshaft pulley with only cylinders #1 & #4 rockers installed. If my recollection is correct, it was every 1/2 turn of the crank pulley I could hear the slapping noise. Hope this explains clearly what I've been having. Thanks.

Tony

My suggestion is to isolate the source of the noise. Is it valve train (cam, valves, rockers, etc.) or reciprocating parts (crank, rods, pistons, etc.)?

As Tippy suggested, back off the valve adjustment on all rockers, then rotate the engine by hand and see if the noise persists. Listen and observe the moving parts.

Reassembling a basket case is risky if there isn't any history on what was done to it prior to your taking over the project. Did you inspect parts and measure the typical clearances during assembly? Were the heads rebuilt? Any parts machined that could modify factory specs? Did the short block (with and without heads) rotate smoothly w/o noise?

Conservatively, I would remove the top end and heads and inspect the pistons for any damage, insure the crank and attached parts rotate cleanly, then double check all parts before/during reassembly. Performing incremental checks increases confidence that no steps (or parts) were bypassed.

Best wishes.

+1. Eliminate the cam/valve /timing issue and see if you still have a problem. if you need to, pull the rockers (hopefully you can do that without disturbing too much). Then if need be, put them back row by row - ie 1/4, check rotation etc.
A long route, but sure to identify source of problem. Good luck.
Alan

"She voluntarily offered to me to use the kitchen for two weeks and being the motor out before February 7.

In short, I was allowed to bring the engine and engine stand into the kitchen. My wife hates the odor of gasoline and oil. So to overcome this problem, she is running an electric deodorizer to mask the odor of the engine. I was able to assemble and complete the engine before the Super Bowl Day. "

Take very good care of your wife, she's a gem.

^ +1

Maybe the valves are bend because of the wrong timing when the cams were on the wrong side. And now when you spin the engine the valves are shortly stuck in the guides but become loose soon because auf the valve spring force...

Bent valves investigation.......
 

The intake and exhaust valves of cylinder #6 were replaced after a stray nut got into the cylinder causing the rocker arms to break. Anchor Atlantic did the machine work. At this point, I have to test and confirm if the valves are sticking or nut. Without the rockers installed, the crankshaft rotates without producing this peculiar noise I am observing.

The next step of the investigation as suggested earlier is to isolate the valve train and drive train which I will perform immediately. Could someone make a comment if I could remove the valve springs insitu (cam tower installed) using P7I & P7E tools? I have not done this test before so anyone with experience please chime in. Thanks.

Tony

Are any of the valve guides cracked inside the port bowls? If so, as MaRu stated, you could have contacted the valves by the Pistons when the banks were backwards.

Don't know the answer to removing the valvesprings. But, you should be able to move valves by hand slightly, then a screwdriver (careful not to scratch parts!) move as far as needed.

Yes, these tools work with the cam tower in place. One is sized to bear on the intake valve stem and the other is for the exhaust. Obviously the rockers have to come out first. You will need to pressurize the cylinder at TDC to hold the valves against the seat (I use my leak down tester for this).

Yes you can remove them in situ. I did some a few weeks ago. I made a special tool to compress the valve spring. (I used to replace them at the track on an earlier race car). You take the piston to compression TDC - or any where if you have the cam disconnected. Lock it in place (TDC helps), you compress the cylinder to around 100 psi (I use my leak down tool). Then you lock the valve spring tool in place (screws on to a stud) and lever on the spring. You will be surprised how easy it is. It helps to give the valve keeper a whack with a socket first - breaks the seat between the collets and keeper.
I can post a pic of my valve tool set up on a valve if you want (home made - like most of my special tools). I have an engine apart at the moment.
regards
Alan

Valve spring removal........
 

Steve,

Thanks for the information. I am looking to buy a P7E and P7I tools for the test. Thanks.

Tony

Picture of special tool....
 

Alan,

Could you post a couple pictures of your valve spring tool? Appreciate taking time to help 911 enthusiast. BTW, where are located in NZ? Are you close to Auckland? I will be visiting your beautiful country in a couple of weeks. Thanks.

Tony

Tony,

The P7 tools are very compact and can be used with the engine installed (not that I would want to try that). Since you have the engine on a stand, access is much improved and other tools could be made to work. Sounds like Alan has a design.

Are you 100% positive that the cams are on the correct side? It almost seems like the rocker is pushing down and releasing at the wrong time, hence the rockers having excessive play in them at certain points in the rotation.

My tool was originally made for a non- P car. But with a small tweek, worked on the porsche. You can see the connection for an air hose in the spark plug hole too. Made that from a drilled out spark plug (and welded some galv tube to it).
I was trying/hoping to find some loose valve seals (to avoid a tear down). I was out of luck and the tear down is underway.
This tool needs the cam box removed to fit in there - but you could make something more compact - like I say - it was made for another engine. But it can be done.
I haven't seen the factory tool.
I am not in Akl - about 5-6 hrs drive sth.
You are not on a cruise boat by any chance? Another Pelican is due here in a few weeks on a cruise boat.
Good luck.
Alan http://forums.pelicanparts.com/uploa...1455583281.jpg

Black 993,

I have rebuilt more than a dozen 911 engines and some of them are extensively used as track cars. Never had any major problem in the past until I started to work on this motor (14th motor, actually 13th to test run). I rebuilt the motors and test run them before the owner/s come and pick them up. Year 2015 was a very memorable time for me because I had undergone two eye surgeries, discovered to have an irregular heart, spent 2 months in Asia and Australia, 3 weeks cruising the British Isles, 4 weeks in Monterey, CA for the Rennsport Re-Union, etc. Pretty good achievement for someone who does not know what he's doing.

CIS troubleshooting is my bread and butter. You simply did not comprehend or misunderstood the post. The FP was fine with the old engine harness but has problem with the newly made wire harness built by Timmy2. Explained to the wire fabricator that there was a problem with the new harnes that has to be corrected. If I didn't know anything about CIS FP operation, how do you think you could convince the fabricator about his defective product?

The fact that I could make the newly rebuild engines run in my test stand and a pretty decent CIS troubleshooter is some achievement for someone who does know what he is doing. How about you, how many engines have you rebuilt? Any technical contributions to the community? Keep us posted. Thank you.

Tony

Yeah, I wouldn't sweat the comments, but I too questioned what you meant by the rocker moved with the lobe.

Figured you simply worded it funky.

You'll get this one, it is just becoming a PITA to reach root cause.

Cam tower installed during removal......
 

Alan,

You have the cam tower installed as shown in the picture. I will probably order the P7E and P7I Sir Tools very soon. My wife and I are on a Cruise from Auckland, NZ to Sydney, AUS. After the cruise, I will stay in Sydney for several weeks and come back home by the end of April. Wife stays behind until end of May. So I have the whole house for me.

My wife allowed me bring the motor inside our house but was not able to bring the motor down to the basement because the ramps I use for bringing the motor down to the basement were under two feet of snow last month. So it got stranded in the kitchen. I promised to get the motor out before Super Bowl but with problem I have now, I was given an extension date. Notice what's on TV screen. Forget it. You guys play Rugby instead.

http://forums.pelicanparts.com/uploa...1455589779.jpg

Do you or your buddies need some parts I could hand carry to NZ? I am not bringing my golf clubs so I have plenty of luggage space to spare. PM me.

Tony

Tony,

Black993 wasn't really helpful. No need to explain yourself. Every expert had to get past number 13. You are just having the joy of doing it publicly in the 21st century.

But the kernel of truth is you've put a lot of stress on yourself. Time to step back and digest the data. I think you'll solve the riddle.

Hi Tony - very kind offer to bring something, I just shipped a new P/C for my 930 - $200 freight. I keep Fedex in business. But right now, I am good. Enjoy your holiday.
The pic I posted I just mocked up with the tool so you could see how it all works. But the head on the tool is a bit big to fit down the cam tower. Only just - but I had to pull the towers to check for valve seals. But a small adjustment would make it do-able with cam tower on. That would be the way to go if you can make or beg/borrow a proper tool. It is quite easy to do. Fitting the collets back in may be a bit of a trick down that orifice, but if you can avoid tearing the motor down again, worth it.
I once stripped my M/cycle down in my bedroom - but I only had a girlfriend at that time, and the bike was more important if it came to an issue. She is my wife now, so she is well educated in this stuff.
Buy your wife something nice on the cruise and forget P engines while gone.
I hope I still have the ability and enthusiasm to get up each day and tear into a P motor at 73. I am also retired and spend half my time trying to make my track car go , and when it is going, trying to make it go better. At least I don't have to do it in the snow. I built a nice shed for my retirement.
All the best.
Alan

Heres' the P7x tool in use. It is pricey, but well made, quite compact and tailored for this application. The P71 and P7E are slightly different to account for differences in the intake and exhaust valve to stud geometry.

http://forums.pelicanparts.com/uploa...1455630347.jpg

The plastic star wheel and allen wrench are not standard with the tool. It comes with a straight handle.

P7X valve tool.......
 

'78SC,

Does the P7X work for both intake and exhaust valve spring removall? Where did you source it? BTW, I have a '78SC too. Thanks for the post with the picture.

Tony

I think the P7 (x) means P7 (I) and P7 (E)
Alan

Thanks for the clarification, Alan. Sorry for any confusion.

Have you tried slackening the valves off yet - as suggested earlier?
Alan

Alan,

No. But I will be doing it later after I get home tonight. I am currently sitting by the ladies dressing room while my wife is shopping for dresses at Nordstom Rack in King Of Prussia Mall. This engine rebuilt is causing me a lot of downtime and $$$$. Some Good Samaritans are lending me these tools tomorrow.

http://forums.pelicanparts.com/uploa...1455658649.jpg

It will start investigating and removing the rocker arms, valve springs, etc. to check and test each valve. If you have any suggestion please let me know so I could incorporate it. Will keep you guys posted.

Tony

Don't let the valve spring split locks drop into the oil drain tubes. Plug the tube openings and have a magnet handy to capture the locks.

S

Good luck. That is good news some good soul is lending you the tools. Don't forget - you need to pressurise the cylinder you are working on. And lock the engine - you don't want it rotating with 100 psi behind the piston. Once your wife gets the new dress I would break the news you also need your compressor in the kitchen/w/shop - for a short while. You need the pressure to hold the valves shut while you push down on the spring. I find a sharp crack with a socket on the keeper before that helps it break free. But it may already break free since engine hasn't been running.
I would try slacking the valves off first - in case the issue becomes clear without having to pull the springs. Then maybe, if the issue isn't obvious then, try adjusting just one set of valves and see what happens.
Regards
Alan

You just saved me from another debacle.....
 

Sherwood,

With all the things going in my rebuild, I got to be aware of the things that could go wrong. This is what I have listed on my reminder list; magnet pick-up tool, tweezer, leak down tester, piston @ top position during removal of valve spring, nut & washer, 13-mm wrench for mounting P7E/I tools, a piece of plastic tube for pushing/pulling the valves up & down, install spring back before going to another cylinder, etc. What else?

Now, I have to add about plugging the return oil tubes that skipped my mind. Do you approve if I apply some lubricant to the valve stem and valve guide? I am planning to have some sort of plastic tube to hold the valve close or in place so I could move from one cylinder to another without installing the springs during my investigation. Do you think this is a prudent course of action. Any comment, remarks, suggestion from you or anyone is welcome. Thanks.

Tony