I have a 1990 740 Wagon with B230 (non-turbo) engine with 180k. I have already cleaned most of the gunk from the engine that resulted from a bad camshaft seal oil leak, no bellypan and years of neglect.

At the present time, the valve cover is off, distributor is removed, valve lash has been adjusted, top timing cover is off, old timing belt is still attached. I do not have on hand the waterpump, tensioner, timing belt and lower seals to do the timing belt job now, but I will be doing it soon -- maybe in a couple of weeks. The camshaft seal is leaking buckets and I have a new valve cover gasket, valve hushers, and cam seal in hand. While I am here, I want to remove the camshaft to clean it up (especially the heavily varnished distributor socket)and check out the camshaft seal groove. I am hoping to replace the cam seal without removing the rear timing cover, if possible, since I will be back later for the timing belt. I have checked the fAQ, but I want to double check my procedure to avoid disaster.

1. rotate engine with the Harmonic Balancer nut clockwise to TDC #1 piston.
2. Mark the belt and cam sprocket to make sure the timing belt goes on the right tooth on reassembly.
3. Loosen the bolt holding the CAM sprocket and the belt tensioner.
4. Clamp the timing belt above the lower cover to make sure it doesn't move off the lower crank and intermediate shaft sprockets.
5. compress the spring on the tensioner and remove the cam sprocket and belt from top sprocket.
6. Break loose the cam retainer cap bolts. Back them all off 2-3 turns at a time to allow the cam to rise slowly. Keep the numbered caps in order.
7. Lift out the cam from the rear.
8. Clean everything up, change the hushers, lube everything when replacing it.
9. Lube cam seal ID and slip it onto the camshaft, leaving it about 2/3 in and about 1/3 out of its final position between the head and the front cam holdown.
10. Use a little hypalon at the mating surface of the front cam cap to seal the crack there and place the rest of the caps on.
11. Screw down the camshaft 2-3 turns at a time to lower it progressively.
12. Torque nuts to 14 ft-lbs. (Is this dry or with oiled nuts?)
13. press camshaft seal in the rest of the way 'till flush with front of head.
14. replace cam sprocket and torque to spec.
15. replace timing belt, release tensioner and tighten tensioner bolt.
16. Rotate engine a couple of turns and loosen then re-tighten tensioner bolt.

Have I overlooked anything in this procedure? Any warnings?

After having replaced the front cam seal without removing the lower belt cover, crank damper, etc., I would offer up the following comments. By the way, this only applies to 700/900 series with a cam-driven distributor:

1. rotate engine with the Harmonic Balancer nut clockwise to TDC #1 piston.

- - At this point, make darn certain that when the crank is at TDC, that the cam is on it's mark also. If the marks on both shafts don't align simultaneously, yet the car now runs good, then the outer ring of the harmonic balancer has spun. However, even if that's the case, it's not the end of the world. With the cam on it's mark, paint a mark on the harmonic balancer aligning at TDC.

2. Mark the belt and cam sprocket to make sure the timing belt goes on the right tooth on reassembly.

- - No marking really required.

4. Clamp the timing belt above the lower cover to make sure it doesn't move off the lower crank and intermediate shaft sprockets.

- - Also not really necessary, as the I-shaft timing is not critical, and you will have visible timing marks on both the cam and crank. (The mark on the crank may either be the factory mark OR the painted mark you applied due to a spun damper.) The heck with the marks on the belt - they aren't a very reliable way of indexing the shafts anyway. Also, even though you can't see the crank sprocket, it is quite easy to tell if the belt teeth are locked into the sprocket teeth.

Additional note: Even though the cam seal won't fit through the hole in the rear belt cover, I was able to replace it by removing the sprocket and just bending the rear cover forward enough to get the seal behind the cover and over the end of the shaft.

Also, you would probably do this anyway, once you remove the top belt cover, stuff a rag in the opening on the top of the lower cover to avoid dropping seals, tools, etc., down inside.

Good luck.

My harmonic balancer is OK and reads correctly at TDC with Cam pointing to its mark. Thanks for the reminder and I will add the rag to the lower cover opening to avoid having to go fishing.

I have now successfully removed and cleaned up the camshaft and caps, the mating surfaces of the head, the shims and valve pusher buckets, and have removed the old bits of petrified valve husher. My ultrasonic cleaner works wonders on hard to reach places. The camshaft hole for the distributor shaft was pretty well gunked and now it is ready to rock and roll. I cleaned up the groove worn in the camshaft by the old seal with 800 grit, then 1500 grit. there is still a depression, but no sharp edge to cut the new seal. In reading up on seals for the distributor rebuild, I found out that you don't want to polish the shaft to a mirror finish. There are no microscopic nooks and crannies for the oil to stick to an the seal can run dry.

I stuffed a rag between the valve spring washer and the valve bucket sidewall to prevent the tiny pieces of husher from falling down into the guts of the bucket pocket. I used a shop vac to pick up every bit of old husher that broke off during removal. I wish there were a way to replace the valve seals without removing the head, because I am sure they are brittle, too. If I could replace them, then the head would have all new rubber.

I wish there were a way to replace the valve seals without removing the head, because I am sure they are brittle, too. If I could replace them, then the head would have all new rubber.

It can be done. Camshaft removed. You rotate the crankshaft until the cylinder is at TDC (valves closed). There is a device that screws into the sparkplug hole and accepts an air chuck. Apply air to force the valves to remain closed.

Now the hard part. Find the tool that will compress the valve spring so as to remove the keepers and release the tension. Remove the spring and replace the seal (there are only four to do the exhaust valves do not have seals).

These tools are available but you need to find one that will work on the Volvo. Within the last year a person with a broken Volvo valve spring reported his success at fabricating a tool and replacing the spring.

Randy

Thanks for your thoughts on replacing the valve seals. I reviewed the old posts regarding replacing broken springs, etc. and at the same time I thought about substituting the rope trick for the compressed air in holding the valves up.
Since I do not have air at home, the rope trick is in.

There was considerable discussion about the universal valve spring compressor sold by Harbor Freight, etc. but the ones that are like gear pullers will not work due to the valves being down in the holes for the cam follower buckets.

I found exactly the right tool for compressing the springs on Volvo 230 type engines. It is a K-D 3087. There is an older discontinued model, the K-D 2400 which is similar. The cheapest place I found to buy the tool on the web was $44, but it was not stocked locally and wouldn't come 'till next week. Fortunately for me the local independent Volvo dealer had a tool that he uses to do this that he was willing to loan me. He also sold me a sleeve that Volvo makes that covers the sharp edges and keeper channel of the valve stem so that the new valve seal can be pushed over it without being torn up. It's kind of like a heavy duty soda staw with a tapered opening on one end. This Volvo place has been really kind to me.

I am going to do a dry run on the engine in my wrecked 245 to make sure I have it all down before I do the 740.

I figure that I'd rather replace all the rubber while I'm here then to have to come back later.

Since I do not have air at home, the rope trick is in.

I am sorry but the rope trick will not work for this procedure. The rope trick is a way of preventing the piston from moving beyond TDC when you are attempting to remove the crankshaft bolt so that you can remove the crankshaft pully/vibration dampner- it "locks" the crankshaft.

When you remove the spring tension on the valve it will want to fall into the cylinder. The compressed air will create enough pressure that the valve will be forced to stay closed. It is also necessary to lock the crankshaft so the air pressure will not force the piston down (although I imagine the piston could be at bottom dead center since with the cam removed the valve will not respond to crankshaft movement).

I do not know of a way to change the valve stem seal with the head in place without using compressed air to pressurize the cylinder and hold the valves closed.

Randy

Randy,
I'm a little unclear as to why the rope trick will not work.
It must be done four times -- once for each cylinder.
Since my engine is now sitting with piston #1 at TDC, and the camshaft is off, I would rotate the crankshaft clockwise about 90 degrees. Insert the rope thru the spark plug hole -- lots of it to make sure that when the piston comes up the rope presses against the entire top of the head including the two valves.
Then rotate the engine ccw back 90 degrees or a bit less until the rope presses tightly against the top, keeping the valve closed.

With the rope keeping the valve from dropping when the the spring is released, I should be able to change the seal in the same way as if air were holding the valve. To be honest, the air method scares me a little, because if the valve gets accidentally pushed down enough for the air to escape, the whole valve will drop into the chamber as the air rushes past the open valve.

Unless I misread earlier posts, others have used the rope trick to keep the valves closed during head-still-on-engine broken spring replacement.

The rope trick must be done to all four cylinders one at a time so that the intake valve is held up against its seat by an almost TDC piston with the somewhat compliant rope. The only way this might not work IMHO, is if the valves are extremely recessed in the combustion chamber and there is a significant ridge between the valves that the rope would run into before it pressed against the closed valve. I have not seen the combustion chamber side of a B230F Head, but since the valves are straight and next to each other, I would think that the whole head area is rather flat and thus able to be held in place by a big wad of rope.

Steve,

If others have used that method successfully there is no reason you can't as well.

After thinking about it you will be able to tell immediately if the rope does not have the valve held firmly in place and will have the opportunity to reposition it.

You have done your homework. Let us know how it works out.

Randy

I don't think you will be able to (4) until after you have done (5).

(6)/(11) I normally use one rotation at a time on the cam cap nuts progressing as you indicate.