Rough idle, loss of power on accelleration, IMS?

[Schnell Gelb]

Somebody dropped it into the intake system accidentally? Is it magnetic?

[Morissey]

I am the only one who works on this engine. The last time i did anything engine related was check the air filter and put it back. 4K miles prior to that was an oil change. Perhaps something went in through the intake?

[Morissey]

Oh, does not seem to be magnetic. Although it was tough to tell as it is a small thin piece and the magnet kept gravitating toward the valve head.

[Morissey]

Hi, I am back. Heads and cams reassembly is complete and ready to time the engine. I have the timing tool, but do I need the Porsche tensioning tools as well? I have read mixed conflicting views on the topic. The shop manual clearly requires them in the procedure.

1. Do I absolutely need these to get the timing right? Item B in image below

2. Is there a hack or trick to avoid this tool? I have read pumping the stock tensioners in oil would set the correct pressure...not sure about that

3. Does anyone have a set they care to rent? I have searched and realized they are not readily available for purchase or rent.

 

Any insight/help would be much appreciated.

 

[Ahsai]

If the debri on the exhaust valve was not from the intake side, is it possible it's sucked in from the exhaust side e.g., a loose piece from the cat? May be worthwhile to check to avoid reoccurrence.

 

 

 

[Morissey]

Excellent point. I will do that. Thanks

[Schnell Gelb]

10 hours ago, Morissey said:

Hi, I am back. Heads and cams reassembly is complete and ready to time the engine. I have the timing tool, but do I need the Porsche tensioning tools as well? I have read mixed conflicting views on the topic. The shop manual clearly requires them in the procedure.

1. Do I absolutely need these to get the timing right? Item B in image below

2. Is there a hack or trick to avoid this tool? I have read pumping the stock tensioners in oil would set the correct pressure...not sure about that

3. Does anyone have a set they care to rent? I have searched and realized they are not readily available for purchase or rent.

 

Any insight/help would be much appreciated.

 

E. is Essential ans 2x F.

 

A. is a 5/16" bolt. C. won't fit with the engine in situ. B. not essential in my experience

 

[Morissey]

54 minutes ago, Schnell Gelb said:

 

 

Thanks for the response and confirmation that item B is not essential. In addition, I am replacing all tensioners with new ones so pumping them with oil should do the job well enough.

 

 

[Schnell Gelb]

Thant is based on my experience and reports from others. I am sure it would be nice to have the pretensioners but they are very expensive.

Be prepared for maybe having to adjust the valve timing after about 1000 miles - using the 4 bolts on the EX cam behind the scavenge pump

[Morissey]

Hmmm...

 

I did mark the timing location of the bolts on exhaust cams prior to disassembly. So I put everything back on including the original tensioners and the marks did not line up on either bank while allocating the cams using the timing tool. I have to move the crank off TDC for the marks to line up, thus misaligning the cam notches relative to the cam cover.

 

The misalignment is identical on both banks, and I am sure the chain did not skip and both sprockets were held in original position on the chain the entire time. 

 

I did replace the chain guides on both cams and wonder if that has caused the discrepancy. What are your thoughts on this? Should I button the engine back up aligned to original marked position?

[Schnell Gelb]

It may help others to give a more competent opinion than mine if you :

Look at the dwg in the FSM of the timing procedure. It is common(& O.K.) that the camshaft notch is not perfectly horizontal. Unfortunately , this is a bit vague.

So maybe to help the discussion ,re-time the cams so the notch is perfectly horizontal and note how many CRANKshaft degrees it is 'off' .

Assuming the notch on Bank 1 is slightly up(&outward) - just like the FSM dwg., I would continue and run the engine.Then asses with Durametric, re-asses after 100 miles and recheck the timing .

[Morissey]

On 10/30/2017 at 9:59 PM, Ahsai said:

If the debri on the exhaust valve was not from the intake side, is it possible it's sucked in from the exhaust side e.g., a loose piece from the cat? May be worthwhile to check to avoid reoccurrence.

 

 

 

 

You were absolutely correct. The cat is the where the debris came from. Shook the header and some more pieces came out. Turns out the rock I rolled over last year had put a good gash on the unit and it had been waiting to get into the head.

 

Searching for a good used cat to replace....

 

Thanks!

[Ahsai]

I'm glad you found the culprit!

[Ahsai]

Btw, may be a good idea to examine all the cylinders and valves very carefully and make sure the debris didn't spread to other cylinders.

[Morissey]

7 minutes ago, Ahsai said:

Btw, may be a good idea to examine all the cylinders and valves very carefully and make sure the debris didn't spread to other cylinders.

 

I have rebuilt the heads, so no chance of that :)

 

Thanks!

[Ahsai]

That's good. I'm more worried about the cylinder side because small debris may get stuck between the piston crown and the cylinder wall above the top ring.

[Morissey]

3 minutes ago, Ahsai said:

That's good. I'm more worried about the cylinder side because small debris may get stuck between the piston crown and the cylinder wall above the top ring.

 

Ah got you. Yes, I thoroughly sprayed the walls and the cavity at the crown with cleaner and rinsed out.

[Ahsai]

That's great to hear.