A combination appeal to the Volvo Gods, and call for wisdom.

Timing belt broke while son driving the 1989 740 GLE, we call it the Hooptie, the balancer belt was also broken- in fact I think this belt failed, which then took out the timing belt.

Decided this was a chance to delve into a major repair project. Gathered info and tools. Removed cylinder head. Twelve of sixteen valves bent up. All were very crusty. Two valve guides were cracked. Pistons looked ok, number four did have a very small ding on top.

Replaced all valves with new ones. Replaced two valve guides (that was difficult, for the record). Lapped valves by hand- could perhaps have done better. Put everything back together, with new head bolts. Getting cam shafts seated with their position correct for TDC was difficult- was initially off by one tooth on intake cam. Installed new timing and balancer belts, put the rest of the hooptie back together. Started the car- caught and ran, but very very rough. Let run for a couple of minutes. Then checked timing marks- the two cam marks were further off- about a quarter revolution. So, I think the belt slipped(?). Removed timing belt. Moved drive shaft to TDC, each cam to proper place, reinstalled timing belt. Cranked around a few times by hand, all good and aligned. Unfortunately, hooptie will not start. Has gas, has spark. Tested compression. Has none.

So, looking like a few more valves mashed a bit when it ran rough. Or possibly bent when re-aligning shafts. Wondering about running the compression test with a dead-cold engine (instructions say "start the engine, run to normal temp, then do the test"- not so helpful).

Next step will be to remove once more the cylinder head, check out the valves. Other culprits may be the intake manifold gasket- I was not as confident this was bolted back on to spec. I am hoping nothing involving pistons.

Further questions will be when to perhaps give up- doing this in spare time. Car is is good shape, with only 144k on the motor, and it was purchased for a song- I like this car, and want to see it back to life.

Advice?

 

Sounds like you hurt the valves again. If you have 0 compression it doesn't matter if the engine is cold or hot. I guess you need to pull the head again and see what you have. By the way back when I did my own valve jobs I would test for leaks by putting the head valves up on the bench and fill each valve pocket with fuel and look for leaks. Re-lap if necessary then clean and install the cams. Good luck

 

Here is an update, with more questions.

I had a good day last week available, so the cylinder head is removed. To my -for now pleasent- surprise all sixteen valve are still straight and nice looking. So the loss of compression is not at least due to recrunched valves, and I was also lucky enough that the initial misalignment was not serious enough to cause more of that damage. The lapping of the new valves may still have been an issue. But, now I seem to have two prime suspects for the compression issue.

Suspect 1 is the head gasket and cylinder head surface. When I removed the head this time, the new gasket was fairly easy to remove. On the one hand, perhaps expected for a head gasket that had not been on the car for very long. Also, some of the smaller openings in the gasket do not precisely match the holes in the block- I am going to double check part numbers, but now wonder whether this gasket is for the B230, not the B234F that this car has. I also did not have the head resurfaced, and in hindsight this could be one of my mistakes.

Suspect 2 is the piston rings. The piston cylinder walls appear nice and smooth. Before the timing belt failed, there did not seem to be any significant issues that jive with bad rings- the car ran well, had no abnormal oil consumption, no noticeable coloration to exhaust, and the car had good power. Because the car ran before the timing belt broke, and did have compression enough to start for a short time after reassembly, it does not seem likely to me that the rings would fail abruptly now. But I could be wrong about that. I do wonder whether the "lawn mower engine" syndrome could be a culprit after the head rebuild?

Advice on which of the two suspects is more likely is appreciated. My next steps will be to take the head to a shop for resurfacing. The shop can also check the valve guides and seals (I installed all new stem seals). I will get a new head gasket, double checking fitment. A related question- I did not use any spray sealant on the head gasket. On this and other forums, a KG copper spray seal seems to be recommended. Leaning towards yes on that.

Last sort of related question. This would not mess up the compression, but I was not quite satisfied with the red anaerobic gel sealer for the cylinder head-to-cam carrier seal. Thinking of using another liquid gasket product for this. Advice/experience on that?

 

When you're lining up your crank, which timing mark are you using? There's two of them near the top of the crank pulley, one that looks to be vertical, and another that looks to the angled to the left (when looking straight on). According to the Chilton's manual, you should align it to the mark that's angled. There seems to be differing instructions online, but my car is running great and its been a few months now. Keep in mind that the timing marks will only line up after tension is applied to the belt. This is most likely the reason for your belt being one tooth off in the first place. Its both a bit of guess-work and experience to align the timing belt properly. The painted marks on the timing belt becomes very useful in this case.


Unless you have no clue what you're doing, lapping your valves by hand should be pretty harmless.


I am not a fan of any installation procedures that aren't from the factory, such as using a copper spray on the head gasket. I feel it impedes the ability of the headgasket to seal properly since you're not getting perfect metal-on-gasket contact anymore.


As for your compression issues, there definitely is a specific head gasket for the B234F, though it would most likely cause oil starvation and coolant issues rather than compression since the block is the same as the B230...at least that's what I understand.


A flat cylinder head is absolutely essential to proper operation. Another essential part is proper pre-torque and angle torque for the installation of the head bolts. Did you use an angle-torque gauge when installing head bolts?


Cam timing which slipped to 1/4 turn off would either tell you that you started the belt installation incorrectly, or your timing tensioner is due for replacement. During installation, did you ever turn your engine counter-clockwise? If so...don't do it again. It will absolutely mess with your timing as the timing belt is not designed to turn counter-clockwise and will lose tension and your timing marks will skip (anecdote from personal experience). Even if you've turned the engine one tooth too far, resist the urge to turn it backwards to save a few minutes.


What makes you unsatisfied with the red gel sealer? If all the mating surfaces are flat and clean, any generic anaerobic sealer will work fine. The question then becomes whether your surfaces were flat and clean to begin with. Did you apply it properly with foam roller? Were you absolutely sure that there was no evidence of previous sealer on the cam carrier? A cam carrier not sitting flat on the cylinder head can absolutely cause compression issues due to the camshaft not seating properly and thus, the valves not seating properly.


Finally, did you hear any "ticking" noises before or after the rebuild? If so, you may want to consider replacing your valve lifters. Speaking of valve lifters, if you didn't replace them, did you make sure to re-install them in the exact location of where they came out? Failure to do so can cause the valves to not seat properly or worse, bend your valvetrain. Depending on how much material you removed from your valves from lapping, your valve lifters might need to be replaced anyways. Valve lifters are designed to "extend" easily, to take up the slack between the valve and the cams. They should not "compress" quickly and/or at all (going by theory and intuition here...) which is what would need to happen for your lapped valves. If the valve lifters did not change position, you potentially have a problem where the valves will never seat properly. Admittedly, this final theory sounds far-fetched, but its definitely a potential.


Good luck.

 

Ok, time for another update, which also makes it clear my pace of work on this is a bit slow. Took the head in to a local shop to clean, check and smooth. Everything was good, and the head surface was made super smooth. All the new valves, from after the initial repair, were also fine. The hydraulic tappets, which were original, were inspected. Most of them were squishy- you could very easily depress the mechanism, the others were very firm. Given that when the timing belt broke, and the result was 12 very bent valves, I decided that damage to the tappets had a high probability. So, replaced with 16 new ones. Rechecked position of the two counter-balancers and their belt, and crankshaft at TDC. I confirmed the new head gasket was the right one for this model, reinstalled all the valves, bolted on the head (torque wrench and protractor to torque and final rotation angle specs were used). Used red loctite 510, and roller, for the cam carrier to head seal. After a few days, installed the cams and distributor, managed to get both cams aligned to their marks without much fuss. Reinstalled timing belt- this one has the manual tensioner. Spun crank twice by hand, all aligned!

 

So did it start and run? By the way after I do a valve job before I remount the head I pour gas in the intake ports to check if any of the valves leak. No compression is usually due to leaking valves.

 

After a minor hiccup (forgot to replace water pump seal, so that coolant leak needed attention)- victory! Started right up, and runs very nicely. So, I will point to the machined-smooth head surface, and the new tappets as the solution here. Now a few minor details. There is a high-pitched whine, syncs with RPM, that needs to be tracked down. Seems like a belt (too tight?) or one of the rollers. Also the coolant temp gauge is not reading on the instrument panel- so need to check that connection, wires, etc. The only other minor issue is a slight roughness at idle (seems a bit slow)- so vacuum hoses, and (hoping not) MAF sensor? Driving it around, will check timing belt tension after a week or so. But, it's nice to have this good '89 GLE 16v on the road again.

 

The high-pitched whine is associated to a balance shaft belt that is not properly tightened...too tight as you guessed. Read online for proper tightness, but it should be installed looser than you might think. As opposed to some solutions online, I tightened and loosened the belt a few times by feel with the engine off to get it just right. I'm not one to condone belt tightening on a running engine.


You seem to be on a good path to solve your roughness at Idle with vacuum hoses. Speaking of vacuum hoses...check the following spots for vacuum leaks:

• PCV and oil separator box and all its associated seals (there's a seal right down at the engine block)
• Oil Dipstick tube, and oil dipstick itself (Again, seal at engine block)
• Throttle body shaft seal, as well as Throttle switch seal
• IACV Hoses
• evaporator canister and all its associated lines.

Finally, clean your MAF sensor before you consider replacing it. MAF's are pretty robust in this car in general. If you measure engine vacuum and you're pulling a good numbers, you're well on your way to a properly running B234F.