SIGNIFICANTLY more demoralizing than I'd hoped!

[printjunky]

Just got back from trying to diagnose my odd-acting distributor drive mechanism - in a minor-league ballpark parking lot! (during a game)

Pulled the oil filter housing - of course the gasket ripped - but nothing seems amiss with the grub screw. Maybe backed out a little, but there and apparently doing its job.

So, what the hell? Pull the pan. And pull the oil pump. Oil pump works like a champ. Spins smoothly, displays no odd behavior.

When I look in the pan, I find this (mystery part 1b) in the bottom of the pan. Get back under and look a little more closely, and after some fishing around in front of the #1 bearing cap (up by the timing cover) pull out mystery part 2a.

Any ideas? I haven't started trying to see what it might be yet. If I had to guess, I'd say cam-related (hence the "popping of the dizzy drive gear).

[printjunky]

Well, I'm pretty sure it is the "thrust plate" on the end of the cam shaft. In my parts manual, part #ERC1651. Any other opinions? Other than how much this sucks (and is going to suck to fix)? Sure feels like a day I should give my "maybe I should just give up" thread a bump. In the year since I first started it, I haven't had the Rover running for more than two weeks total before something else grounds it. I JUST WANNA DRIVE IT!!!!!!!!!!!!!

[SafeAirOne]

It's kind of hard to tell by the pics, but to me, that doesn't look like part of the cam thrust plate. That plate is just a thick, perfectly flat piece of machined steel. The part in the pic looks like it was factory-formed, though I can see your reasoning as any forward/rearward motion of the camshaft could cause the distributor skew gear to rise and fall, theoretically.

[printjunky]

Mark, I should have mentioned. These things have been SERIOUSLY munched. It's obvious one went through a timing gear. They appear to have been originally flat with one coppery (bearing) side. The flatness implies they were not bearings. There is also part of an apparent former bolt hole in each piece. Only one way to tell, I guess. Dig into the timing cover. I have to drag the thing home first. Might gonna be a surreptitious late-night strap-tow (only about 2 miles).

Shower, dinner and a beer first.

[SafeAirOne]

Interesting. I was just looking at pics of as timing chain tensioner and damper pad to see if anything matched up to your pics. I'd think these would be more likely candidates. You'll know soon enough one way or another...

A thrust plate would be a VERY unusual failure.

[printjunky]

Agreed, that would be mighty odd for that to go. Whatever it is, it suffered a pretty violent demise. The other things you mentioned are certainly possible. Though the copper bearing surface is a tip. IIRC the dampener is on heavier stock than this, as well. I guess I should also keep in mind that this could possibly be something totally different - even something left in by a PO inadvertently, and it rattling around, bunged up whatever's causing the "popping" in the dizzy drive system.

I think our definition of knowing "soon enough" might vary, as I am dependent on natural light (otherwise triple-strength bug spray) and weather cooperating with any work. Forecast looks good for a timing cover pull. Unfortunately.

[Apis Mellifera]

I've not taken apart a 2.25, but I've been in many MG A and B Series engines. It is possible in those for a thrust washer to be so worn that the crank can move forward. In Triumph engines the thrust washer can fall completely out allowing the crank to move significantly. This movement can drag along the cam. Thrust washers have that copper surface.

It sounds like the cam is moving causing the drive gear to misalign with the driven gear on the distributor. If the popping sound is actually coming from the timing chain, it could be trying to jump a tooth - damaged tensioner.

The pass/fail test for thrust washers on the MGs and TRs is to press in on the crank pulley nut while someone presses the clutch in and out. Any TW wear is very clear in the crank moving in and out.

You can test for timing chain wear/slack by observing pushrod movement in response to slight back and forth crank movement.

[crankin]

Interesting. I was just looking at pics of as timing chain tensioner and damper pad to see if anything matched up to your pics. I'd think these would be more likely candidates. You'll know soon enough one way or another...

A thrust plate would be a VERY unusual failure.

My vote is for the tensioner pad. I just removed my timing cover and replaced things in here. My pad was broke off and it looked a lot like your piece.

[printjunky]

Well, I have the breakfast and rad off. Hopefully will be able to pull off the timing cover today and see what's up in there.

I also might as well do some regasketing on a couple of other items while I have this kind of access. The oil fill and fuel pump bases weep a tiny bit - less than a drip, but I think I can get them fully sealed back up. (The 8 years the engine sat in a barn [then 3 in my driveway] was probably not good for the gaskets). And while it's out, I'll probably make sure the rad good and clean and have it pressure tested.

Any other suggestions on what I might tackle while I'm in there as far as preventative measures and overall maintenance go? I know I'll be relatively close, but I will not be able to pull the engine this time. I'm working in my back yard and don't have an adequate facility/gear (hoist, stand, etc). I do need to do my rear main, but I will have to do that on my back. That leak's non-catastrophic, so will have to wait till I get this sorted, anyway.

[SafeAirOne]

Well...probably goes without saying but if some metal objects have run through the timing chain and gears, you might want to have a good look at them to see if they and the tensioners, are in need of replacement.

[o2batsea]

Any other suggestions on what I might tackle while I'm in there as far as preventative measures and overall maintenance go? I know I'll be relatively close, but I will not be able to pull the engine this time. I'm working in my back yard and don't have an adequate facility/gear (hoist, stand, etc). I do need to do my rear main, but I will have to do that on my back. That leak's non-catastrophic, so will have to wait till I get this sorted, anyway.

This is called shipfitter's disease. Next thing you know you'll have the whole truck down to the chassis getting it ready for a frame over.

[printjunky]

Does it get worse? Yes. Yes it does get worse.

So here's what I found as I pulled the dog/pulley and timing cover after work today. The parts I found crushed up in the oil pan appear to be the locker for the bolt and big three-holed washer that hold the timing gear to the front of the cam.

The bolt that holds all that together was just sitting in there loosely, and the first 6 or 7 threads were shaved right off. No way to know if it came loose, or if the locker blew up and then it was loose. And then other damage happened. Doesn't really matter. But whatever was going on, it resulted in the keyway on the gear being pretty munched up, the key on the cam also being munched, and the keyway that holds the key on the cam being damaged. All three of those are pictured.

Other than that and the oil seal being riveted (so apparently original - and ripped) everything else looked great in the timing case (gears, chain, tensioner, etc)

Looks like I have to replace the cam. Does this mean I pull the engine, even though I'm not prepared to do so? Well it's either that or do the cam in situ, or mothball the thing til I find a way to build a garage. Anybody done a cam recently and remember how it went? Can I do it plein aire?

[SafeAirOne]

Well...the cam just slides in and out through the front once you get the skew gear and cam followers/tappets out of the way. However, unless you can go through the 2 cam cover plates to move all the followers and tappets up and out of the way while you R&R the camshaft, you'll probably have to pull the head off.

Another thing to consider is that if you are replacing the cam bearings at the same time, some types will require sizing to the camshaft using precision line-honing equipment once they are installed in the block.

[Moose]

Looks like I have to replace the cam. Does this mean I pull the engine, even though I'm not prepared to do so? Well it's either that or do the cam in situ, or mothball the thing til I find a way to build a garage. Anybody done a cam recently and remember how it went? Can I do it plein aire?

Swapping the cam is easy if you are not changing the bearings and the procedure can be done with the engine still in the truck. I think you already have some of the work done. Rad out and distributor and drive gear out. Next the head needs to come off then the tappets/rollers/slides need to come out, then undo the two bolts at the fuel pump and move it off the block. Take the cover off the front and the cam should slide right out.

Brett

[printjunky]

Well, I'm gonna pull it. The difference between pulling it and pulling the front cover and the head off is negligible IMHO. In fact after an hour today, all I have left is the bellhousing bolts, the starter, the exhaust, and the ground strap. I do NOT want to own a hoist and an engine stand (when I don't even have a garage to let them rust and collect dust in), so hopefully I can find one to borrow. The rear main needs done anyway, and I suspect it will be MUCH more likely to go well doing that on a stand rather than on my back! And the oil fill and fuel pump need new gaskets. Not exactly leaking, more like barely weeping, but still, maybe I can get that closer to not leaking at all. And I'll be able to do a better job on the front case and oil pan seals. Also, I can address a pushed out freeze plug (that has a rubber expansion pug in right now)

I will have to try to stick to the plan (and hopefully not find anything else amiss) if I want to be driving it again by August.