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I am at a bit of an impasse with this timing belt job. I'm supposed to set the engine to #1 firing, TDC, and I'm supposed to get that Crank pulley off (with the 24mm bolt). It's been my intention to get the pulley off and, when I can see the timing marks on the crank sprocket, line everything up then. The belt is very slacked and slipping at the crank sprocket. I'm assuming that the teeth on the belt have been damaged where the sprocket has been rubbing while I troubleshot the problem out(even though the rest of the belt looks fine - as it did when I checked it in the fall), so I have a Goodyear belt all prepped to go on as per forum recommendations. [Unfortunately the only thing being changed today is the belt itself. Tensioner, seals, and harmonic balancer all have to be ordered but car must be moveable from street parking by Wednesday. Another belt will need to be installed then also as their are seal issues]
It is my understanding that the crank pulley with it's 3 belt grooves is what mechanics are calling the harmonic balancer(?) and that there is a rubber inner sleeve which damages easily if the crank pulley is muscled the wrong way. I do not have access to the volvo tool #5284. I was considering using some metal strapping (the kind with the holes) to afix the pulley to the tensioner bolt (since it looks like that's what the tool does(?))... but I am very reluctant as I am of limited means and cannot afford to replace the pulley if I damage it by improper removal. I recently read in forum that someone with a manual transmission used the transmission in 4th with brake pressure to hold the crank in position. I have a crank position sensor so the inspection plate option is a no go. Q#1: Can a similar thing be done with an auto trans (low gear with brake)? Q#2: (a)How does the tensioner function? (b) Do I need to relieve tension before removing the bolt which appears to hold the tensioner? Am I setting the belt tension to 37 ft.lbs. by adjusting the bolt which passes through the tensioner bearing or by some adjustment of the spring mechanism which appears to provide the actual tension?
I was planning, once the pulley and remaining timing cover half are removed, to utilize the crank and cam timing marks to establish #1 firing TDC, then install the new belt as per forum recommendations. I was hoping that I could just use a socket and ratchet to move the crank and cam into proper alignment. Is that how it's done?
Thanks for any and all responses.
Wayne
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"...the crank pulley with it's 3 belt grooves is what mechanics are calling the harmonic balancer(?)"
Yes.
"...a rubber inner sleeve which damages easily if the crank pulley is muscled the wrong way..."
Yes, but it may not be quite as sensitive as that. You can remove the pulley vigorously... and usually, it just about falls off.
"...do not have access to the volvo tool #5284. I was considering using some metal strapping..."
Look in the FAQs for the "rope trick." (No, it's not tying the pulley with a rope.)
"...Can a similar thing be done with an auto trans (low gear with brake)?"
Nope.
"How does the tensioner function?"
The tensioner moves in to "consume" the extra length of the belt. Once in place, the tensioner's locked down, so it no longer pushes against the belt with constant force. Once the belt stretches a bit, all tension is off. However, it's easy to "re-tension" the belt by loosening the locknut (easily and quickly done through the access hole), which allows the tensioner to move inward a bit. This means that it "takes up" the extra slop created when the belt stretched. And once you lock down the tensioner, then it's fixed in place to "consume" that extra bit of length.
"Do I need to relieve tension before removing the bolt which appears to hold the tensioner?"
To remove the belt, it's best to pull the tensioner back and lock it back by tightening the locknut (I use big mutha channel-locks to squeeze the tensioner back). Then you'll find a small hole in the rod inside the spring. You can stick a small nail through the hole and then loosen the locknut. The nail holds the tensioner in the compressed mode -- this is useful for removing and replacing the tensioner. Otherwise, you only need to temporarily lock it back using the locknut.
"Am I setting the belt tension to 37 ft.lbs. by adjusting the bolt which passes through the tensioner..."
37 lb-ft is the proper torque for tightening the tensioner locknut. It's also the torque for the bolts that hold the sprockets to the I-shaft and camshaft (useful info when you decide to replace the seals).
Rather than getting your knickers in a twist over setting the timing now, simply remove the crank pulley and belt. When you're ready to reinstall the belt, turn the crank to TDC (align the mark on the crank with the mark on the seal housing) and set the camshaft to TDC (align the mark on the sprocket with the mark on the rear timing cover).
You can usually turn the crank easily by slipping the pulley onto the crank and tugging or turning gently by hand. The engine should turn easily.
The cam turns easily using a wrench on the bolt. I prefer to always turn in the "tightening" direction to avoid unintentionally loosening the bolt.
When you install the new belt line up the marks on the belt with the marks on the three sprockets. (This is a double-check of proper timing.)
Read up on the "rope trick" -- note that the process changes when re-tightening the pulley bolt (vs. when loosening the bolt). Do NOT use an impact wrench on the pulley bolt.
(Rope trick.)
--
Don Foster (near Cape Cod, MA)
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Don;
Thanks a million for the info! Just one more thing. I want to minimize any chance of damaging any valves (not that I really understand how it can be damaged by doing the rope trick incorrectly). I'm not sure what I'm lining up to insure #1 firing TDC. I assume that the standard which overhangs the crank pulley is timing related - corresponding to marks on the pulley(?) (so long as harm. bal. is not defective) - and that #1 firing TDC may be achieved with proper alignment of a mark on the pulley with another of the standard...(centering a pulley mark in the middle of the overhanging standard markings?)... Am I correct in this assumption? If not, with the cam sprocket being inaccessible behind the lower half of the timing cover, is there another way to determine #1 firing TDC? I've read in forum that the #1 plug compression can be felt with the plug removed. What am I feeling for? Where is #1 firing TDC in relation to that felt pressure? You stated in your overview of the rope trick "...making sure you're setting TDC for #1, and making sure you stage the piston to push UP against rope." are two important musts. I don't understand how I insure those two things. I don't have a problem with aligning a mark on the pulley with some mark on the standard which overhangs it - if that's how it's done - then going an additional 90 degrees and cramming in the rope... but I'm unsure if that's all there is to it... If the pulley and overhanging markings are all I need to set #1 TDC, you don't need to get into the compression thing because I'm just going to center, add 90 deg., cram in the rope, and loosen. I further assume that I cannot allow the pulley to rotate beyond the TDC orientation as it's then that I risk valve damage(?)...
Thanks again. I greatly appreciate your helping me.
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"...minimize any chance of damaging any valves..."
Be absolutely sure that you "pre-stage" cylinder at TDC between its compression and power strokes (as opposed to between the exhaust and intake strokes, when valves would be open).
At the proper TDC, the valves will be closed. You can determine this two ways:
(1) Remove the oil cap and observe the cam. At the proper TDC, the intake and exhaust lobes will be facing up (meaning that they're not pushing the valves open).
(2) You can remove plug #1 and feel for compression pressure as the piston approaches TDC in its comp or power stroke. If you're approaching the wrong, TDC, the valves will be open and you'll feel no pressure.
"...not sure what I'm lining up to insure #1 firing TDC..."
Line up the mark on the flange (sits on the crank) with the mark that's cast into the seal housing. The flange has a notch on its rim and is keyed to the crank.
"...the standard which overhangs the crank pulley is timing related..."
Yes, but if the pulley is off and the timing belt cover's off, then those marks aren't available. They're sitting on your workbench.
"...can be felt with the plug removed. What am I feeling for?"
Serious air pressure trying to push your finger from the plug hole.
"Where is #1 firing TDC in relation to that felt pressure?"
Think of it a different way. If you feel the pressure, then you know that the valves are closed (versus open) as piston #1 approaches TDC (which you determine by watching the marks).
If the timing belt is off, then this approach is nonsensical because the cam's not camming and the valves aren't valving. In that case, use a wrench to turn the cam until its timing marks line up. Then the cam is in the proper position for the proper TDC. (Clear?)
Regarding the rope trick, with everything still assembled.....
1) Be sure that you're at the "proper" TDC (discussed above).
2) For loosening the crank bolt, turn the crank about 1/4 turn CW and then stuff in the rope. As you loosen the bolt, the crank turns CCW, jamming against the rope.
3) For tightening, go to TDC and turn the crank about 1/4 turn CCW and then jam in the rope. As you tighten the bolt, the crank turns CW, and the piston jams against the rope.
This is simple stuff. Sorry it seems confusing or intimidating.
The images below were scanned from the Haynes manual and apply to the B21/23 engines. The B230 is very similar, however. In particular, look at image 9.4a, which shows the location of the timing marks on the sprockets, flanges, and block.
Also look at illustration 9.7, which shows the rear belt flange on the crank. You can see the small notch in the edge and how it aligns with the tab cast in the housing.
--
Don Foster (near Cape Cod, MA)
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Wayne,
As usual, Don's advice is right on target, but I would expand on a couple of points...
1) "When you're ready to reinstall the belt, turn the crank to TDC (align the mark on the crank with the mark on the seal housing)..."
The TDC marks align twice — for #1 (which you want) and for #4 (which you don't) Make sure you are at #1 TDC by feeling for the piston top thru the sparkplug hole. (If you get it wrong, #1 will be at BTC, and you will need a LOT of rope for the "trick"... just kidding.)
For future reference, when you have #1 TDC, remove the Oil Filler cap and note the position of the 1st two cam lobes—each slightly up, and pointing away from its mate.
2) "When you install the new belt line up the marks on the belt with the marks on the three sprockets."
With the cam-driven distributor, the Intermediate shaft isn't a timing concern. It just drives the oil pump
Also, I'd suggest pulling all the plugs to make it easier to rotate the crank by hand.
--
Bruce Young,
'93 940-NA (current), '80 GLE V8 (Sold), '86 240dl, '85 244 ti, '83 245t
'76 244 (R.I.P at 255k), 73 142 (98K), '71 144 (ex circle track car)
Used '70 144 from '78 to '92, New 144 from '67 to '78, Used '62 122 from '63 to '67
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