I have a 1991 740 8 valve wagon. 250k miles

I replaced the engine on this car with a used engine from a PnP at 230K. I had a Volvo mechanic do a leakdown test and a compression test last year. Both he said were great.

I had them done because I always wondered about the engine. I changed the oil with Mobile 1 10/30 and gave the car to my daughter to drive to college. When they got there they found that I had forgotten to replace the Oil fill cap and oil had sprayed out on the hood pad and the engine. They topped off the engine with about a 3/4 quart and replaced the cap that was still sitting where I had set it. Everything Great.

She drives it back home 2 weeks ago and I go to take it down the road and it stalls at the end of the drive. It's a rex/regina my first thought is the single in tank fuel pump or relay. I check both and they seem OK. I check for spark on the #1 plug and there isn't any spark. I look at the RPM sensor and the wires are suspect. I order a new RPM sensor and install it. The car still will not start.
Still no spark so I think it might be a coil. The rex/regina coil is big dollars but I buy it and install it.
Still does not start.

Now I'm puzzled and figure that maybe the timing belt broke even though it had 20k on it. I take the timing cover off and the belt is off the crank gear. I try and turn the cam and it will not turn.

Did the Cam seized from the lack of a Oil fill cap or? I'm needing ideas.

When I put the engine in about 20k ago I replaced the oil pan gasket and the bottom of the engine looked real clean.
Thanks, Mike

I doubt a seized engine would keep it from turning over. It might sound like somebody was grinding a piece of metal in a coffee grinder but it would still turn over. It sounds more of an electrical problem to me.

for the belt to have jumped off, something might have fallen into the open oil fill hole.

Remove the Valve / Cam cover and see why the camshaft wont turn and if that looks ok then check the distributor since its connected to the camshaft.

It sounds to me like the timing belt has either broken or the tensioner gave way and the bet has jumped teeth. The belt could have even jumped teeth through oil contamination.

A lot of garages do change just the belt on these cars and neglect the tensioner assembly. It should always be changed with the belt.

The most probable reason why the camshaft will not turn now is because a valve or two has touched a piston and then bent. They kink in the valve guide and jam.

This will be why the camshaft will not turn. It cannot push the valves up and down.

The best thing to do is take the cam cover off and have a look at whats going on in there. Try turning the cam backwards and forwards and see what its doing.

Hope this is of help.

I thank you all for your input. Here is the latest.

When I removed the top timing cover originally. I saw that the belt was off of the crank gear. I tried turning the cam gear by hand and it didn't move. Maybe just slightly, therefore I jumped to the conclusion that the cam had seized. I took the valve cover off and looked at the cam and it looked fine. I put a 14mm socket on the cam gear bolt and turned the cam fine against the valve springs tension. I am going to remove the crank pulley, and the lower timing cover and see if I can figure out why the timing belt jumped/slipped.

Anybody hear of a worn crank gears teeth? the cam gear looks ok. I replaced the timing belt and tensioner when I put the engine in. Maybe a bad timing belt or fatigued spring on the tensioner.

I still haven't turned the intermediate shaft.

Thank you all again.

I will let you know what I find.

Also, I would like to mount a mechanical oil pressure gauge from the block into the passenger compartment. I want to see the oil pressure with a quality gauge once I get the engine running.

Mike

It's very unlikely that the crank gears are worn. It sounds like the belt tension was not right. Also this is a non-interference engine so the valves should not be bent.
You can mount a mechanical gauge into the B230F engine, but it's easier to fit an electrical gauge and for most purposes the electrical gauge will give you all the information you need.
If you still want to install one, you will have to remove the oil pressure sender and install a M14- 1/8"NPTF adapter. If you want to retain the warning light you will have to get the B21/B23 sender to replace the metric one and install a 1/8" NPTF t-piece to connect the sender and the oil-pressure line to the gauge.

This site is very informative but i need more details about this topic.If it mentioned means others can easily give their opinion.
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nancyfernandez

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