1998 550 Maranello "sorting" thread--DIY

Photo 1 shows the tensioner in place. Notice that I have wedged a 1/4 inch extension into the tensioner. The tensioner generates force on the timing belt moving to the LEFT of the photo, so applying the 1/4 inch extension loads the spring and moves the bearing to the right of the screen.

Once this is all finished, place the two plastic shields (DONT FORGET THOSE!) to which the timing belt covers fasten over the camshaft ends, and then install the timing cog gears on each camshaft. Each cog gear is labeled with which cam it goes on the inside well. There should be NO dowel in place at this point. The process will continue tomorrow (Photo 2)
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Henry you are too damn funny...but since you mention it I did purchase a whole new OEM carpet set for the interior, as my tan carpeting just doesn't look good. It has been previously cleaned but is faded a bit and looks a little dingy. I have seen a few 550's with tan leather and black carpets, and absolutely love the look.

No more cows need to die as my interior leather is in excellent shape.

And lastly, I have spent the last week touching up every chip in the paint, and have repainted the bottoms of the rockers and rear bumpers black due to peeling. Did some wetsanding of RIDS also, as the car's paint thickness is on par with other Fcars I've measured (150-160 microns or so)

 

John...those are both new tensioner bearings.
I replaced one of the two accessory belt bearings. The other was fine.

 

I'd be interested to hear from the other experts here as to whether moving things by hand could indeed bend valves. I doubt it, but I need further information. However, aggressively torquing the cam in the wrong position could do it I suppose. The reports of bent valves that I've seen on these interference engines seem to come from episodes where the engines were running when the interference occurred.

Carl, this is an excellent point and one that bears repeating.
When I laid the cams "flat" they were still not totally flat, but they were flat enough to get the caps on. They were not more than about a cm off with regards to the assembly marks. The point of this was to be able to get all the caps to be able to sit on the studs far enough to have the nuts threaded on finger tight.
Once all the nuts had several threads grip on the studs, that's when I rotated the cams by hand (with gloves on). The point of this is that the cam caps are a weak point here, not the cams themselves. As you said the cams are quite strong.

A couple of other points. All of my lifters are new and therefore all have 1-2mm of "spring" travel to them. This means there is some give to the lifters and not all the force during the rotation step is directly transmitted to the valve stem. Half of my old lifters were frozen with no play and i think this could have been a bigger problem if I reused them.

The cams were not fully tightened down and torqued until they were fully lined up.

Sark, the assembly marks all line up on both banks when piston 1 is at TDC. When you check cam timing of bank 7-12 you need to find TDC of cylinder 7 also. I will detail that later.

 

Dave, thanks very much for the information! I guess if when I start it up it sounds like silverware in a garbage disposal I will know what happened!

FBB scared me enough this morning that I went back out and looked at the cams I had put in. At TDC on cylinder 1, the lobes of the cams are not depressing the lifters of cylinder one at all, so I hope I'm okay. I was extremely careful putting them back in to not force anything so I think everything will be okay.

 

This evening I picked up where I left off after conferring with a few experts in the field.
Many thanks to them for their kindness and patience with a lowly DIY-er like me

When we last talked I had placed the cog gears on the cams without securing them. They are able to move somewhat loosely without moving the camshafts at all. At this point I locked the tensioners in their "loosest" position by wedging a prybar onto the tensioner base and cranking the spring out, and then tightening the tensioner bolt (marked "X" in the photo) to hold it at maximum looseness. This makes it easiest to apply the belts, which are quite robust. (Photo 1)

After sliding the belt in place, which takes some force and a very slight manipulation of the loose cog gears, I had the timing belts on in proper location. Do not fret if as you slide them on you see a little bit of white crust on the cog gears..this is the wax overcoat on the kevlar coming off, not the kevlar itself (Photo 2)

At this point, take the cam bolts which hold the cogs in place and replace the o-ring seals, and then coat each bolt with a light film of Molykote BR-2 or Permatex Copper antiseize. (Photo 3)

Then, thread the bolts into the ends of the camshafts but do not tighten them, not even finger tight. DO NOT PUT THE DOWELS IN AT THIS POINT. You want the cogs to be able to move independent of the cams when you loosen the tensioner bolt and apply tension to the belt (Photo 4)
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At this point, you can loosen the tensioner bolt and let the tensioner pulley apply tension to the belt. It is not going to jump...it just takes up any slack you see. Tighten the tensioner bolt by hand so it doesn't wobble back and forth.

Once this is done, the next step is to unscrew the cam bolts and remove one at a time, so you can get a good look at the holes in the cam cog. The camshaft also has holes, and with any luck one of the cam cog holes will align well enough with one of the cam holes below such that you can place one of the metal dowels in. If it is just about there but won't go all the way in, don't force it, just put a gentle thumb pressure on the long travel of the timing belt while simultaneously pushing inward on the dowel with another finger. I was able to get all 4 in this way. Replace the cam bolt and screw in finger tight, taking care to note that the dowel sits in a groove on the inside of the cam washer. (Photo 1)

At this point you have the cam cogs locked to the camshafts such that rotation of the crankshaft by hand will drive all 4 camshafts. You are NOT finished however, as you must determine the belt tension and set it appropriately.

Rotate the crankshaft two full revolutions to seat the belts, and then break out your handy harmonic cambelt meter

The cambelt meter has attached to it a small microphone, which when held close to the belt can sense the frequency at which the belt oscillates when plucked with a finger. You must measure the timing belt of each bank at two points, which is the midpoint of the two lengths of the belt, and then sum the two values together to get a final number in Hz.(locations pointed out in Photo 2 and Photo 3)

It takes a little practice to pluck the cambelt correctly to get consistent readings, but after a few minutes I was able to get consistent numbers. You can see the red MotoReva meter above my left hand in Photo 4. Hold the mic as close to the midpoint of the cambelt length that you can, and pluck it with the other finger. Record the values. You need to take 5 separate sets of readings, rotating the engine over in between each one by hand, and then average the five readings. Each reading after rotating the engine is slightly different, but should all be pretty close to each other.
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Sark,
If you "let the spring set the tension", the numbers came out at 195 Hz per bank. General Fchat opinion (from reading prior threads) is that this is too loose.

The WSM for the 575 belts states 330-360Hz. The way you increase the tension on the belt when the "spring setting the tension" is to loosen the tensioner bolt, and then rotate the engine by hand and retighten the tensioner bolt while the timing belt is moving. Then rotate the engine over and recheck the tension. It will be significantly tighter this time.

I will not reveal the numbers I chose to set the timing belts to. The last thing I want to do is take the blame for someone replicating what I do and having a disaster. I am solely responsible for my own vehicle and the choices I make on it. Suffice it to say that I am a believer that the recommended tension in the WSM is too tight, evidenced by the amount of rubber dust present when I removed my covers.

 

Okay...I've been fiddling around with timing the motor the last couple of days and believe I have finally succeeded in getting it to where I want it to be.

I previously detailed the WSM method of setting the timing on the 550, in post number 106.
This method is a "lift at TDC" method, and it is also the easiest for me to understand. The WSM doesn't seem to give enough information to use any of the other methods.
I will detail the "lift at TDC" method, and will set my car exactly to the factory specs.

In order to set the timing, the bare minimum you need is:
1. a HIGH QUALITY dial indicator gauge, with a relatively long extension (4-6 inches). I chose a Mitutoyo. I actually used another "off brand" dial gauge first and could NOT get the numbers to be even remotely accurate. I machined the extension to a flat, small diameter point so that it could fit as correctly on the tappets as possible.
2. A TDC plate, which I detailed in a prior post and which can be made from Lowes stuff.
3. A good quality rubber mallet. Tape the ends with electrical tape for reasons I will detail later.
4. I think an impact gun is important for this job, but it is not mandatory.

PRECISION IS CRITICAL HERE. Every last hundredth of a millimeter counts because the more exact the timing the better the car runs. If you have ADD or lack patience don't do this job.

Start with bank 1-6. Rotate the engine to some point PRIOR to TDC on the non-firing stroke, lets say 40-50 degrees. The cam assembly marks line up on the firing stroke. Rotating the engine 360 degrees clockwise from TDC on the firing stroke gets you to TDC on the non-firing stroke. (Photo 1)

Place the TDC plate on the second set of screw holes back from the front of the cylinder head, over the second spark plug hole. Place your dial gauge holder on the plate and position the dial gauge so that the tip of the probe is on the intake tappet of cylinder 1. Be as precise as possible in adjusting the pointer and angle of the probe so that the direction of deflection of the probe is as close to the direction of travel of the tappet as possible. The probe needs to be TIGHTLY screwed into the dial indicator and must not be excessively flexible. Any deflection of the tappet needs to precisely and directly deflect the gauge. (Photo 2)

At this point (40-50* before TDC on the non-firing stroke) the intake cam has not begun to deflect the intake tappet of cylinder 1. Set the dial gauge to zero. Verify that the probe of the gauge moves up and down freely and does not rub on the lobe of the camshaft, and then reverify that the gauge reads zero. Now, rotate the engine in the driven direction (clockwise) and approach TDC. When you get to about 10* before TDC slow down, because your goal is to stop the engine rotation exactly on TDC. Slowly complete the rotation by stopping the engine exactly on TDC. I used my degree wheel to determine where TDC was but if you have dial gauges coming out of your ears you could set a second dial gauge on the cylinder surface to determine it that way.

At the point where your engine is sitting at TDC on the non-firing stroke the dial gauge on the intake tappet should read EXACTLY 0.70mm +/- .05mm.
When I rotated my engine and measured, it showed that the cam was just a little bit advanced from what it should be (Photo 3). Surprise. The dial gauge read 0.84mm (the smaller numbers on the gauge apply with this direction of gauge rotation). So, I will need to adjust the cam.

Leave the dial gauge exactly where it is, and loosen the intake cam cog bolt. Remove the bolt so you have access to the centering dowel and remove it. You may need to wiggle the timing belt a bit to get it out as there is a little play in the two holes that can cause the dowel to be hard to remove. (Photo 4)
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Once the dowel is out, use a rubber mallet to tap the lobes of the camshaft either clockwise or counterclockwise depending on whether your timing needs to be advanced or retarded. Make sure to have taped the mallet with electrical tape, otherwise each strike of the mallet on the cam lobes will leave behind little bits of rubber debris (Photo 1)

Watch the dial gauge as you tap, as with this intake cam you will be able to watch the gauge approach the correct value you are seeking. Stop tapping the cam when the gauge reads 0.70mm +/- .05mm. (Photo 2)

Once you have arrived to the correct position, reinsert the dowel in whatever hole lines up and allows the dowel to fully go in (Photo 3) If no hole fits exactly, use a flashlight to determine which hole is closest and then gently tap the cam lobe with a mallet to and fro while simultaneously pushing the dowel. It will drop in at some point and then you can use the mallet to then tap the cam back into spec (there is a little play in the two holes).

Once you have done this thread the bolt back into the cam with a new o-ring and after verifying sufficient lube of the threads with Molykote BR-2. Take care to make sure the dowel fits in the slot of the cam cog washer, and then hit the bolt with a few pulses of the impact gun to lock the cam to the gear. Rotate the motor over 360 degrees and repeat the prior measuring procedure to make sure the cam didn't move out of spec when you used the impact gun. Tightening by hand with a wrench resulted in me moving the cam out of spec lots of times, and therefore the impact gun was recommended. You have now set correct timing on the intake cam of 1-6.
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Now, with the engine still sitting at exact TDC on the non-firing stroke, move the dial gauge over to the exhaust tappet of cylinder 1, taking pains to position it as exactly as possible in line with the direction of travel of the exhaust tappet. (Photo 1)

Zero the gauge once it is positioned properly. Rotate the engine clockwise beyond TDC and watch the gauge deflect. As you rotate the crankshaft clockwise, at some point the gauge will stop deflecting and freeze at a number. The exhaust cam is set correctly when the gauge stops deflecting at 0.69mm +/- 0.05mm. Mine was also off a bit. The procedure for adjusting the cam is the same as with the intake cam, with the exception that you will not be able to use the dial gauge to guide you....you just have to guess a little bit on how much to advance or retard the cam's position before you lock it down again. Once you have locked it down again rotate the engine by hand 720 degrees to recheck where it sits now. With some trial and error you can get it into correct spec.

Once you have locked this cam with the impact gun you need to apply final torque to the cambolt, which is 98Nm. Recheck and verify the timing on this bank one more time and you are set to move to bank 7-12.

I used cylinder 12 (the one closest to the front of the motor) on the second bank to set the timing of this bank. The WSM states to use cylinder 7 but in truth it doesn't matter which one you use. Just be consistent. (Photo 2)

Repeat the above procedures for the second bank and you have set the correct timing for your motor. YAY!
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Sark,
No. There are several ways of saying what I'm talking about, so please ask me to be clearer if I misspeak
A 4 cycle engine utilizes two "pumps" of the piston during it's cycle. Starting from TDC on the non-firing stroke, the piston travels downwards, and the intake valve opens to let fresh air/gasoline in. The exhaust valve is just finishing closure as it starts down. When it reaches BDC it begins to rise as the intake valve closes, compressing the fuel/air mix. During this time of compression both intake/exhaust valves are closed. This is what I am referring to as the "firing stroke". When the piston reaches TDC again, ignition occurs (firing), slamming the piston down. During the firing stroke the cam lobes are not exerting any force on the tappets, hence the closed valves. THIS is the position the cams are in when you reinstall them and line up the assembly marks. As the piston travels down to BDC again the exhaust valve opens and the piston rises again, forcing out exhaust gas. At the top of this "non-firing" stroke, the intake valve opens again. As you can see it is during the non-firing stroke that the cam lobes are deflecting the tappets and it is HERE that you measure tappet deflection to set timing.

After my cams were correctly timed and verified, I went around and photographed the assembly marks relative to the cam caps. I was surprised that the bank 1-6 (Photo 1) and bank 7-12 (Photo 2) assembly marks lined up almost exactly. I also realized that my cams were off when I took delivery of the vehicle and started this project, albeit just a little bit.

NOTE: I did not set the timing by lining up the assembly marks. I set the timing by measuring lift at TDC and then after the fact photographed these assembly marks.
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Now the engine can finally start to go back together.

Photo 1 : Waterpump reinstalled, torsion damper reinstalled, all bolts torqued to correct specs. Make sure to use blue loctite on the torsion damper bolt.

Photo 2 : New gasket trimmed and fit, making sure to use silicone sealant at WSM specified locations.

Photo 3 : Repainted cam cover torqued in place. I sure as hell hope I can remember how this thing goes back together. I'm curious to know how many washers I will have left over at the end
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