Unfortunately, I would recommend replacing the lifters and the cams, because they are supposed to break in together. Most likely the lifters were damaged in the collision between the pistons and valves, and putting them back in the right place will not be enough. With the amount of work required to put the engine back together I would do it right the first time.

I agree with post #1, replace the entire valve train.

Realize the amount of pressure at the point of contact of the cam lobe and the two degree spherical grind on the bottom of the lifter is exceedingly great.

The bending of the valves was as a consequence of not replacing the timing belt at the appropriate service interval. Timing belts need to be done around 50,000Miles 80,000Km. Although early watercooled VW's and Audis are at 36,000Miles 60,000Km.

Your motor will have be of the interference type with reliefs in the tops of the pistons to allow for the close tolerances .

Usually when repairing the head after such an event the (good reputable)head shops replace the all valve guides as well as all the valves as the guides get fractured where the valves bend.

Other damage to the valve train and bottom end can be expected. There is no cheap fix, just doing it right.

You'll be better off pulling the motor out tearing it down and checking for bent conrods and galled cylinder bores while your there, as you have contaminated the engine oil with "valve cleaner" then you will need to inspect all the main and big end bearings as well for damage.

As you have found, saving $50 in maintenance has cost you around $2500.00 in repairs.

The Valve cleaner should have gone in the fuel tank, not in the engine oil. Most likely you will have thinned the lubricating properties of the oil. 70 psi is very low compression reading, it should be around 150psi. This engine would barely have started let alone run.

All good fun as they say...

A piston into the valves is like a bull in a china shop. Why is this head being rebuilt rather than looking for a replacement head?

Why are you doing the head work and not a machine shop? Lots of shade tree mechanics have the skills to do their own block work but few have the skills and tools needed to do good head work, particularly after a head crash. You have plenty of busted valves. Try bending one. You'll find it's not easy. Experienced eyes watching for crash damage is money well spent.

I had a piston crash in my 1984 Chevette Diesel and I repaired it all myself. The special conditions were that the valves were not angled to the pistons and the valve train fasteners were weak. The pistons drove the valves straight up without bending them. The bolts popped and saved the cam. A few parts from a spare engine and it was back on the road.

The lifters should be replaced. Other problems have been mentioned but the biggest problem is that each lifter wears to the valve movement distance which is consistent over the life of the lifter but different for each valve position. Swap two lifters. One will fall short of the previous wear mark and the other will go beyond the previous wear mark. With lifter tolerances up in the ten thousandths range it doesn't take much lifter wear to be unacceptable. Then again, I threw 8 random lifters into a GM 2.3L SOHC Quad 4 and it worked.

Any auto parts company can look your lifters up and tell you if they are all the same.

Careful inspection of the block assembly should tell you if it's even salvageable or not.

If not --->>get a used engine.

If it is-->> get a used head fully assembled.

Good luck...it's not a cheap experience however you go.

Engines with hydraulic lifters have cam chains or gears not belts. Belts drive overhead camchafts which drive the valves down by means of a rocker arm pusching the end of the valve or a shim/disc setup. There will be some clearance in the system unless a valve is being driven. Have the heads redone and check the pistons and connecting rods for damage.

Hi Blink, you seem to be the Volvo knowledgeable guy and my Volvo car knowledge ends about 1980.

This string caught my curiosity as back then, when a belt failed they usually just stopped, nothing hit anything, (unless there was 'other slack'), so you just replaced the belt, did a few checks and mostly were back motoring next day.

So I'm wondering when did Volvo engineers decide that things could hit in belted engines? Or if it all has to do with valve cleaner in the oil, say producing "pump-up" in stuck-up (semi-seized) followers? I imaging this 'rigidity' would take out a belt too?

Y/N? Educate me?

Around the 1989 year model 740 GLE, also known as 8+8 and 16V. The option of a twin cam motor designated B234E/F was available as a normally aspirated performance engine . Produces around 153 Hp. This motor has 4 valves per cylinder and two cams. Also has 2 timing belts one for the cams and oil pump, and the other for the two balance shafts.

This motor was an option up to 1991/2 in the 940. The heads are now fairly sought after items as the 2.3 litre ford motor in the SVO Mustang gains considerable performance increase by the use of this head. After some fiddling about.

I dare say the B234 was Volvo's customer "beta" test motor for future applications. As versions of this Hemi style head can be found in the B6304 and whatever they use in the 850 and V cars.

The belts (both of them) must be changed no later than 80,000km/50,000miles or else the gods will wreak their vengance and have no mercy on you.

Appropriate maintenance assures longevity, These motors also have hydraulic lifters instead of shims under the cam follower buckets, this a god send for those who have tried to match up shims when setting the valve lash in a B23/230 motor.

I own two 740's, with one of each motor so I know their peccadilloes.

So I'm wondering when did Volvo engineers decide that things could hit in belted engines?

I'd say in the early eighties. All the twin cam Volvo engines are interference types, and the single cam engines are not.

Or if it all has to do with valve cleaner in the oil, say producing "pump-up" in stuck-up (semi-seized) followers? I imaging this 'rigidity' would take out a belt too?

Interesting thought. Usually pump up cannot occur at ordinary RPM, because the valve springs are so much stronger than the springs inside the lifters. If the valves are floating from over-revving then pump-up is possible: the lifter expands to take up the slop when the valve floats, and then cannot leak down fast enough to keep the valve fully seated. Then on the next opening, the valve floats again and the lifter extends even further, etc. I think this probably did not occur on this engine, but it is an interesting possibility.

I poked around the web for 960 info. Turns out that your pump up theory is quite possible, because these engines are prone to valve sticking. That could leave a valve slightly off its seat, causing valve lash, which the lifters would quickly expand to fill.

One solution for the sticking valves that is recommended, in addition to using synthetic oil, is what we always called an "Italian tune-up" in which you run the engine at high rpm for a while (Volvo evidently recommends 12 minutes at 5000-6000 rpm.) This site has lots of info on sticking valves, timing belt tensioner problems, valve-piston collisions as a result of timing belt failures, etc.

I'd recommend that our OP study the site linked above, and get the factory repair manual. These engines seem to have all sorts of interesting issues and quirks. It could make one nostalgic for an old 122. I remember thinking that the 240 etc. were a step down from the 122, in terms of overall reliability.

While the complications of some replies are possible the likelihood of major engine damage having occurred is questionable considering the information given.

Depending on the method used the compression figures given can be repeated on a fresh new engine

But an experienced mechanic (not parts changer) should inspect the parts including the tops of the pistons with the cylinder head removed to then determine if further inspection is required. Valve guides are not always broken when valve stems bend and 80,000 miles may not have incurred sufficient wear to require replacement unless skipping the suggested maintenance periods was the SOP for this car.

The advice of an experienced mechanic may cost a little and it can save you a bunch. Can you visually inspect the tops of the pistons and determine if one or two have merely been gouged by collision of valves or have they become cracked? Drop the oil pan and inspect for debris and have the oil analysed. Then reply with the result please

But not if the person doing the testing is competent, and if the engine has run for a few minutes.

Score—B+ Though it seemed probable the OP may have not run the engine immediately prior to performing the compression test sequences because the timing belt was broken. I gave you a good answer.

There were no indication so lobbed that out hoping the OP would volunteer more pertinent info.

If an 80,000 mile engine has low compression, is consuming 30% more fuel than normal, and there are heavy tar-like deposits in the back of the exhaust valves, something is wrong.

Could be the bent valves are contributing to this condition ya think?

It would be a shame to bolt everything back together, only to find that compression is still low, because of a cracked/stuck/crystallized/relaxed/worn out ring(s).

I agree do you have more information than that which has been divulged in this thread? Tough tarry goo does develop on the back of intake valves when the mixture is rich, possible causes abound.

If the cylinders are showing 40 psi though that figure is very low it maybe only a bent valve causing the low pressure reading, if the valve is not seating properly, etc.. Without eyes on by a competent mechanic or automotive machinist little conclusion can be determined.

Having been and automotive, marine and aircraft engine machinist I can express that the basics are nearly identical for all; specifications are specifications regardless of make, model and year.

We need more information on maintenance this engine has received, 80,000 miles is extremely low but not unheard of on a fifteen year old vehicle. I own a 1992 with 100,000 miles, the first ten years at about 3000 miles per year were a little old lady driving and she had the vehicle serviced every year even during a few years when the miles totaled less than 500 in case the oil etc got old too.

Maintenance...."A few weeks ago I put 2 cans of valve cleaner into the engine oil."

I agree do you have more information than that which has been divulged in this thread?

There is also the thread immediately before this, named "Hydraulic Tappets." It sounds as if you think this engine has been running with bent valves, but I seriously doubt that it has. As the OP describes it, the engine was running fine but consuming more fuel than normal "prior to the engine failure." He says that the valve tappets were mixed up at the service area, and that he is now trying to reassemble the engine, but has some questions. It appears that the engine has not run since the timing belt failure/valve bending incident -- and it is reasonable to assume that it is incapable of being run with the bent valves. (And in general, only a nut case would throw a new timing belt on an interference engine and then try to run it.)

Bending valves would be a normal occurrence for this engine if it was running at highway speed when the belt broke (although bending all 12 exhaust valves suggests that the timing jumped just before the belt broke). At that point the engine would no longer run, and the engine was partially disassembled for inspection. An ordinary compression test would not be performed at this point because a normal compression test relies on valves opening and closing -- and that cannot happen in this engine. A leak down test could be performed (but with some difficulty); however, the values obtained would not be quoted in psi.

So a reasonable assumption would be that the engine was running OK but using a lot of fuel, and the goo on the back of the exhaust valve heads accumulated while the engine was running -- probably over many miles with relatively low compression, yielding low combustion and valve temperatures, perhaps with some oil leaking past the rings, and perhaps with some oil leaking down the valve guides.

If an 80,000 mile engine has low compression, is consuming 30% more fuel than normal, and there are heavy tar-like deposits in the back of the exhaust valves, something is wrong.

Could be the bent valves are contributing to this condition ya think?

I doubt it. I think the valves were bent as the result of the timing belt breaking, and the engine has not been run since.

As the OP describes it, the engine was running fine but consuming more fuel than normal "prior to the engine failure."

The compression test would have been performed before the failure and the resultant figures indicate running fine as a poor choice of words.

Much of what you've taken for granted doesn't make sense, all intake valves would not be bent under the conditions you've described. There is way too much turning resistance of the cams for them to continue rotation after the timing belt broke and all the intake valves would not be in a position to be bent. Some of the valve bending occurred prior to the timing belt breaking

Dents and gouges in the top of pistons don't necessarily produce detrimental conditions.

I don't presume to know the conditions before inspection.

I don't presume to know the conditions before inspection.

I don't either, but at least I'm willing to make something up!

all the intake valves would not be in a position to be bent

True, although it was actually all the exhaust valves that were bent... but you are correct -- it seems odd that they all bent. It suggests (I'm making this up) that:

1. The the timing jumped immediately before the belt broke. Otherwise, if the engine were running before the incident with all the exhaust valves bent, then the engine would be unlikely to produce adequate power, would be very hard to start (if it could start at all), and the exhaust valves would quickly burn at the unsupported edge... but the owner describes them as looking good.

2. Another possibility is that the inertia of the cam and cam pulley was sufficient to keep the cam rotating for perhaps 1/4 second (may be 1/2 second), even against valve spring tension and collisions. If the owner was cruising along at 2000 rpm, then 1/4 second would be about 8 crankshaft revolutions, with the timing becoming progressively worse. It is a very rare multi-cylinder engine in which the cam pulley can not be turned by hand to align timing marks (with torque cause by closing valves roughly canceled by torque required to open valves, leaving mainly friction from the total spring load being the retarding force.) Guesstimating the torque required at 10 lb-ft would mean that inertia alone would keep the cam turning for a while, with energy absorbed in friction and pulses of valve bending.

All conjecture, of course. Perhaps the OP will come back to describe the sequence of events more clearly.

Your correction of my comment about the valves caused me to re-read the OP's post.

Here's my make it up as I go routine. As I'm reading the description the lines are revealing hidden meaning of a distinct lack of attention to detail of a profitable schedule of preventative maintenance.

If professional mechanical service and inspection is not available, tow to an area with signage "Fill Wanted"

Kyzine,

A part of discovery is the complication involved, a simple answer may not be quite right and a complicated answer not simple.

Of the many factors involved no measure of contribution can be realized beyond that knowledge of dirty oil having low lubricity contributing to sludgy goo in the presence of cylinder head heat. This lubricant condition and leaky valve stem seals may combine to produce gunk deposits on the back side of the valves. However this will not slow the valves, buildup of carbon on the piston top may interact with the valve though this type impact would not be expected to bend a valve stem. Dirty sludge producing oil can cause inadequate performance of the followers too.

Again of the many factors, heat, dirty oil having low lubricity and little attention to preventative maintenance overall and specific to the timing belt failure and had the timing belt skipped a notch causing poor performance over a period to then skip again which caused valve to piston interaction which may have culminated in the breakage of the timing belt. Such an order of progression could produce the result you've described.

The 960 is a valuable piece of equipment when maintained properly and if as Blink indicated the rest of the car is in serviceable condition you may be money ahead to rebuild this engine. If you have more time than money or are of the inclination attend some local adult classes pertaining to auto repair because with some knowledge, patience and a little helping direction you may succeed

A timing belt will break if not changed within a reasonable time .

When a belt breaks your valve train will be damaged extensively.

Also , the aluminum pistons will now have gashes in the crowns that will cause detonation and pre-ignition problems.

As the other guys have advised , you need to completely rebuild your motor or find a replacement long block.

She is 15 years old , is she worth it .?

When it comes to 7 and 9 series Volvo's, they have to be in a really bad state not to be worth repairing. As the bodies are not known for rusting in odd hard to get at places most of the issues are usually poor mechanical maintenace or outright neglect.

Even the base poverty pack Volvos are nice enough to drive on the daily commute, the Upspec ones have all the "features" considered "essential" by todays standards.

I will fess up to owning two 740's (1 saloon, 1 Cammer 8+8 Wagon) they are equal to the current crop of repmobile and hair dressers cars only with more character and predictability.

Best of all I can let my teenagers at them knowing that they'll (the teenagers) come home alive and in pretty much the same condition they left. Not so sure about my cars though... Chances of surviving a high speed impact in a 7/9 Volvo is significantly greater than many other makes of vehicles.

Just my tupence worth..

You have left us with a few questions.

1. Is the head still off?

2. Have you replaced all of the bent valves yet?

3. When did you put the valve cleaner into the oil? Before the belt failure or after the repair? Was the product designed to be put into the oil?

My best suggestion from the information you have provided is to have a competent cylinder head specialist examine your head, and tops of your pistons. Take his advice on how to proceed. Good luck.

Hello Gentlemen and Thank You very much for your information

1 The head is still off

2 Yes I have replaced the valves

3 Before the failure by 6 weeks