996 3.6 3 chain rebuild timing question

Hi, I am rebuilding my engine and getting close to finishing. I have a habit of second guessing myself especially when it comes to cam timing. I have been following the proceedure in the bently and 101 projects books. I started with 4-6 bank, pnned the crank at 1 tdc, installed cams as pictured, cam honlding tool in place no problem. I continued to bank 1-3, pinned the crank dropped the cams in, locked the cams, everything just went too easy. cam holding tool fits in both 1-3 and 4-6 bank with crank in same 1tdc position. Was I suppose to turn the crank 360degrees after completeing installation of 4-6 cams before initiating 1-3 cam installation. I am recalling when I initially took engine apart the cam plate did not fit in both positions with crank pinned at tdc, maybe chain was stretched/worn, or in fact was I was suppose to turn engine 360degrees before initiating installation of cams in other bank? There is such little info on the 3 chain engines. neither of my printed sources mention turning crank 360 degrees cant go any firther until I resolve this Thanks Glenn 2003 C4S M96 03 3.6 LN nickies

That is correct. Otherwise you'll be in for a surprise when you start the engine - only one bank will fire. This should never happen -> "cam holding tool fits in both 1-3 and 4-6 bank with crank in same 1tdc position."

I was suppose to turn the crank 360 degrees after 4-6 cams were completely installed and before 1-3 were installed? none of the printed material says to do this

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Correct. Actually it was printed in one of the older versions (3.4L engine) but in the later versions I couldn't find that. Jake Raby had mentioned multiple times about this easy mistake.

Thanks so much for this info, glad I second guessed myself. To correct this, I need to lock the cams 4-6 and crank to tdc, disassemble 1-3 side, remove cam lock from 4-6, turn engine 360 dgrees clockwise, Pin crank at "tdc" line up cams 1-3, lock cams, bolt the sprockets I turned engine gently through by hand no damage done

You can disassemble either side. No damage was done even with your current setup because each cylinder still have the correct 4 strokes. Just that bank 1 and bank 2 are 360 degree out-of-phase so instead of the normal one compressing cylinder every 120 degrees, you have two compressing cylinders simultaneously every 240 degrees.

Actually it does matter, doesn't it ?

If I reassemble the wrong side it will be on the exhaust stroke when the Piston is going up on number one, instead of compression?

Timing for a bank is correct if you can fit the cam timing tool with engine pinned at TDC #1. For the timing between the banks to be correct, you just need to add a 360 degree offset between them so only one bank will fit the tool at any time.

Doesn't the reference for fuel and ignition timing need to be correct, does that come off of the cams or the crank

Just undo that side and rotate the crank 360 - everything will be fine

Unless the crank is rotated CW 1 full 360* rotation between timing each bank. If this doesn't occur you'll end up with both banks timed the same, which will be an issue. One bank should be @ TDC at the exact same time the opposite bank is @ TDC overlap Of course, we spend 6 hours on this in my hands on class, which is where Ahsai learned about it :-)

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Yeah, in fact we learned the timing procedures for both the 3-chain and 5-chain engines. It makes your head spin

Thanks for all the info unfortunately the published material I was armed with leave bout the important step of rotating the crank 360 after the first bank is timed Glenn

I will be doing this as soon as the rest of my parts come in. Any other tips or tricks you can provide that will help with this?

Get Porsche shop manual , you will thank me later

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have that.

I'm in the same camp, will be doing this soon too. I'm glad I read this thread first! Also thanks to Ahsai who has already been a big help.

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Ahsai rocks!

3rd here to vouch for the man Ashai. thanks for all your help.

My pleasure, guys. Always happy to help my fellow Porsche enthusiasts!

Also back me up guys - but if I already have an IMS tool kit (including the TDC pin and the camshaft locks), I don't need any other special tools to adjust timing on a 3 chain engine right? I've flipped through the manuals and looks like I have everything I need for removing/installing the cams... Looks like the bolt on supports that go on in the middle to hold it down are more for 5 chain adjustments, right?

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Correct. Is your manual specific to the 3-chain engines?

It isn't as far as I can tell - I have a digital copy of a factory manual (I think just for the 3.4?) the Bentley Manual which does have some 3-chain specific stuff (but can't be sure if it's ALL there), and the 101 Projects book.

There is one tool for setting the timing on a 5 chain engine and a completely different tool for setting the timing on a 3 chain engine.

For 3-chain, you need this set http://www.ewktool.com/PorcheEngineTimingTool?product_id=138

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Throw away those and please don't follow any of those! You need the procedures specific to the 3-chain engines. I'll post some links later.

Combine the following and they are ALL you need. Make sure you read AND UNDERSTAND every single step before you even touch the cam covers. 1) Post #20 here https://rennlist.com/forums/996-foru...ml#post7168230 2) http://workshop-manuals.com/porsche/...nd_inspection/ 3) Rotate engine 360 degrees before installing and timing the other bank