If the engine was not smoking, used little oil, and had no noises involving rod bearings and so on then doing a valve job is entirely feasible and not a problem.
For what it’s worth anyway, I’ve done a lot valve work in the past both at dealerships and in my own shop.
This kind of work is time consuming for the money involved. I sold off my valve grinding equipment about a dozenish years ago.
Around here the auto machine shops charge about 5 dollars a hole (meaning one valve and one seat) on a carry-in cylinder head with head surfacing, etc additional if needed.
It’s well worth it to let someone else dink with it.
I would not even bother measuring timing chain stretch. High miles means automatic replacement.
On an older engine that uses a timing light to check ignition timing chain wear can be checked by watching the timing marks on the harmonic balancer. If the mark wobbles around the chain is worn to some degree.
Wear on the guides can be checked with a dial indicator but a far easier and cheaper method is with the fingers.
With the spring off, lower the valve until the end of the stem is flush with top of the guide. Now place a fingertip on top of that area and press tightly.
Now pull the valve out quickly. If you hear a “pop” the guide is good. If the sound is muted or there is no pop the guide is worn, or worn out.
BillRussell , The engine misses & sputters for lack of better terms but doesn’t make any ticking , rattling or knocking noises or smoke & thank you ok4450 .
I’m a driveway diy’er, not a pro. But if I were presented with that situation I’d just remove the head and take it to the machine shop. If the machine shop says the only problem is the valves aren’t sealing, everything else is fine, I’d ask them to do what’s necessary to make the valve sealing surface correct, install new valves, new valve stem seals. If necessary, new springs. I’d let the machine shop decide if the head surface is flat enough and make the necessary adjustments if required. New head gasket, adjust the valves.
Is there a special tool for measuring timing chain stretch?
Each engine has a specific inspection procedure. The following shows how to inspect for timing chain wear on a 3.7L Jeep engine;
To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston (2) extension is obtained. Measure the distance between the secondary timing chain tensioner housing (Fig. 112) and the step ledge on the piston. The measurement at point (A) must be less than 15 mm (0.5906 inches).
If the measurement exceeds the specification the secondary timing chains are worn and require replacement.
BTW, did you check for a broken valve spring on the cylinder with low compression? During the last ten years I’ve seen more broken valve springs than burned valves.
Question 1 how long do you plan to keep the car. question 2 what is the condition of everything else, ball joints, brakes, tires tie rods etc.
You could have gotten the valves fixed for less than the cost of replacing an engine, so were there other factors?
A valve job properly done does not precipitate failure of other components, as stated above.
Nevada_545 , Other than removing the valve cover & closely watching the valves open & close I didn’t further check the springs . Visually to me they looked ok & thanks for the explanation & diagram .
Barkydog , Other than the engine the rest of the vehicle is in very good condition & I’ll probably sell it right away . I bought a complete vehicle with low mileage that had been slid sideways into a pole with the impact behind the drivers door . I plan to use the engine out of it . It still runs & drives but isn’t roadworthy .
Finding an engine that you can hear run and/or drive is always a huge plus. Once the engine is out maybe you can pick up some extra money selling parts from the wreck on eBay, Craigslist, or some internet forum specific to the car. The latter might be the best option.
EBay fees can be annoyingly high and CL seems to drag out the worst in bottom feeders sometimes.
I used to sell a lot of motorcycle parts along with some car parts on eBay and the constant rise in fees and worse, eBay dictating my terms of sale, caused me to just quit selling on there entirely. I do buy things now and then, all depending.
EBay has become pretty much a cluttered Chinese clearinghouse.
I don’t run a shop, but I suppose I would give the owner the facts and let them make the determination on what they want to do, which is what I do when I do a side job working on someone’s older PC.
I know opening an engine , especially a high mileage one , can be opening a can of worms & mechanics can find things internally that wasn’t obvious externally . The things a mechanic knows beforehand that goes with the job is what I’m asking about . Some things related to the job at hand are automatically planned for & done . At least that’s my take on it .
First things first before deciding a valve job is need. Check the valves’ adjustment. While at it, make sure the bottom end and the camshaft are properly in synch.
You are correct. For instance, whenever an engine or transmission is out for whatever reason a new rear main seal on the engine and a new torque converter seal on the transmission is a must.
In my mechanicing history I’ve always recommended this and never charged any additional labor; only the cost of the seals. It’s better to head that problem off rather than install an engine or trans only to have one or the other start leaking a week later.
When installing a used engine a new timing belt kit is also recommended. Some years ago I installed a boneyard engine in a Mazda and argued tooth and nail with the owner (car driven by daughter) that the engine should get a new belt kit. He refused and signed a disclaimer keeping me off the hook.
So what happens? Two months later the timing belt breaks and ruins the top end of the engine.
So who is he mad at? Me, in spite of the disclaimer which he signed and “doesn’t remember signing”.
Believe it or not, I’ve worked in shops where people signed disclaimers and when things went sour actually had the audacity to claim “my signature was forged…”.
Our reply was always that forgery is a crime; you had best go to the police right now and get them involved with some handwriting analysis. That was always the last word on the subject… sigh