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

[boyt911sc]

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

[mreid]

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.

[manbridge 74]

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

[VFR750]

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.

[Flieger]

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.

[boyt911sc]

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

[VFR750]

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?

[john walker's workshop]

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?

[boyt911sc]

Originally Posted by VFR750

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?

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

[Tippy]

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?

[boyt911sc]

Originally Posted by john walker's workshop

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?

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

[boyt911sc]

Originally Posted by Tippy

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?

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

[911pcars]

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.

[Alan L]

+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

[boosted79]

"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.

[VFR750]

^ +1

[MaRu]

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...

[boyt911sc]

Originally Posted by MaRu

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...

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

[Tippy]

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.

['78 SC]

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.

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).