Compression=0...what would you do?

[I Leak Oil]

Zero compression should yield an obvious failure once the head is off. Even with a sligthly blown gasket or a sligthly burnt valve you should be getting a little compression reading with a standard compression test.

[mongoswede]

Unless I missed reading it again: You could put an air line on the compression check hose and then put compressed air into the cylinder at TDC. If you hear air out the exhaust its an exhaust valve problem...intake = intake valve, air out the oil cap or PVC = rings. side of the block could be head gasket.

[HybridIIA]

I'm not sure how well you could see the valve heads with the borescope, but I suspect you have a badly burnt valve.

[o2batsea]

The good news is that repair for a bad valve or broken spring is pretty simple. A holey piston or busted rings on the other hand may be a death blow especially if the bore has scored beyond salvation.
You can still buy Bobeck's Iron Duke Chevy conversion that he pulled out of Red Square. It is a Robert Davis kit that was in there for only a year or so before he went with the 200tdi. Very low miles on it and a real improvement in performance. More or less a drop in replacement for the Rover lump.

[achtung]

Go get a leak down tester and use it, this will end the speculation.

[Moat Creek]

More data round 2- zero compression in #4

Did a little more investigation tonight

1) No coolant in oil
2) No oil in coolant
3) Ran vehicle for awhile and coolant level never went down & no bubbles.
4) Exhaust does not have condensation or unusal smell
5) Ran motor until hot and ran 140 PSI into cylinder # 4 and never could stop air from leaking out exhaust. Rotated engine by hand and could never find a sweet spot where the valves sealed #4. No air bubbles or surging in coolant.
6) Measured valve height on # 4 and compared to a couple other valves when closed and rocker arm had some slack. Exhaust valve height measures .035 less then intake valve.
7) Measured all tappet clearances and they were all .012-.017 except exhaust valve on # 4 which was .032.

I guess next step is to pull head this weekend and verify that #4 exhaust valve is burned/bent or other wise damaged. Once I get if off I will have to sort out if it makes sense to get a rebuilt head or some lesser fix..... let me know if I missed anything. Is it possible to just replace valve if valve seat is not damaged or is my only option to have mine rebuilt or order a remanufactured one?

One good find was gas was spitting out of my rebuilt BV carb where the two halves of carb meet (I had compressed air running in #4 & intake valve was open). Looks like I get an oppurtunity to fix another possible vacuum leak source & may need to adjust float agian
I just replaced that gasket when I installed correct jet.... I knew the paper based gasket wasn't as good as a impregnated/fiber one. I guess I will have to find a good source for a new one.

Thanks again for your input!

Eric

[SafeAirOne]

Is it possible to just replace valve if valve seat is not damaged or is my only option to have mine rebuilt

If the valve seat is good and your valve is just sticking, you can just have the one valve and the guide and its seal replaced, but If it were me and I had the head off and at a machine shop anyway, I'd just have them do a complete valve job and replace all 8 valves, guides and seals. No point in doing this again in 6 months.

The only counterpoint might be if you don't have an unleaded head, you may choose to go that route instead.

[o2batsea]

Remove the cylinder head. I'd plan on sending the head out for a rebuild. Have them install the hardened "no-lead" exhaust valve seats. You will want at minimum new valve guides and seals and have the valves relapped. I'd also pop for new springs. Don't allow them to skim cut the head unless they are absolutely positive it has a warp.
That should take care of the head.
Your main worry is the engine block. If the #4 piston bore has been scored or damaged in any way the engine will have to come out for repair. You will see and be able to feel by running your finger around the inside of the bore. If it is at that point where it needs an overhaul you will have to determine if your wallet and gumption are up to the task. No matter how you slice it it's at least a $3000 job, whether that is cash or labor or time or a combination of all three.
If you spend that and still have a $4000 truck, I'd begin to rethink the worth of pursuing the whole business.

[I Leak Oil]

I guess next step is to pull head this weekend.....

I think that's been mentioned a few times already.

[4flattires]

I'm just coming up for air after working on a shower remodel (ok and windows too), so getting up to speed on this post.

Hey...so since the head is coming off...how 'bout some pics?

I'll check back in 15 mins so we can see what the culprit of #4 is.

[achtung]

I'm just coming up for air after working on a shower remodel (ok and windows too), so getting up to speed on this post.

Hey...so since the head is coming off...how 'bout some pics?

I'll check back in 15 mins so we can see what the culprit of #4 is.

Better to just sit at your computer and click refresh all day.
Seeing as the valve clearance is greater on that cylinder I am suspecting some obstruction on the seat.

[Moat Creek]

Update: The good the bad and the real ugly

Well I pulled the head off the engine and things did not look so good....poor rover. (see attached PDF file)

The good news is the head gasket was in terrific shape and not the cause of the lose of compression . The exhaust valve in #4 would not close all the way so that is probably the cause of the zero compression I suppose.

Looks like a piece of the piston was bounced around in #3 & 4 before becoming embedded in crown. Not sure I have ever seen pistons look like this before. The head cannot be reused since the pitting is so deep that machining would remove to much material. The cylinder walls look surprisingly good and are not damaged (all 4 show mild signs of wear).
I measured the diameter at the top of the cyclinder (don't have proper gauge to measure further down) and from what I can tell from the green bible the block should be able to be bored out or have liners installed.

Not sure what I will do next. I can order a rebuilt head but finding a engine rebuilder in LA area is real difficult. No local supplier in area has rebuilt engines so I would need to order one perhaps from our host...shipping would be costly. I guess I can also take the craigslist route & try to find a good used engiine but that would take time & could end up with different issues unless it was recently rebuilt. Much to think about.... after a 1.5 years of complete teardown/rebuild of my rover freind I am getting real anxious to get it back on the road.

Thanks for all your input!

Eric

[VTBKRDS]

Your engine is SPANKED. Save yourself the aggrivation and order the reman. from our hosts. Having seen many blown engines, this one will require a MAJOR overhaul. Once you pull the pan, you'll find the piston pieces down there and possible crank and rod damage. You will have as much, if not more $$ into repairing this one, than just getting the reman.. That's if you do find a reputable machine shop to help you out. (my 2 cents) Good luck.

[Apis Mellifera]

I'd disagree with the engine being a total loss. I've seen that kind of damage before. I once supercharged an MG Midget I had and something was sucked in and bounced around inside cylinders 3 and 4. The only reason I noticed was that it developed a misfire because the plug gaps were peened shut. The pistons looked much worse than yours. I put the engine back together, replaced the plugs and it kept going for years and years.

I don't think that piston fragments did that damage. They are aluminum and I don't think an aluminum shard would affect the cast iron head like that. I'd guess something was sucked or dropped into the carb or parts of the carb broke off. My first thought was that the rings broke, but the cylinder walls look OK. You could reuse the head. Remove the sharp spots to stop detonation and don't worry about what isn't cleaned up by a head skim. I'd have it magnafluxed, though.

Clean the head up, new pistons, new valves were necessary, new head gasket, and keep driving while you look for a good replacement engine.

Buying a rebuilt engine would be my Plan Z.

I'd take that valve out to see why it's hung open. Perhaps some of the debris that caused the damage is still trapped there. Is there debris embedded in the top of piston #3? Will it come out and is it magnetic? There looks to be what appears to be the electrode from a spark plug stuck in there. The valve sticking could be unrelated to this damage. Perhaps in this Rover's lifetime someone did this and you only found it now because a chunk of carbon broke loose (which is not uncommon) or normal deposits on the valve have made it stick. Had this valve been open for a while, it would be burned or possibly flame cut.

[albersj51]

I agree with Apis...the cost of the reman engines is pretty steep. Tear it down and see what the machine shop says. A major overhaul will likely be a lot cheaper than the remans.

I think there is a "recently rebuilt" 2.25l on landroverexchange.com right now.