Fouled Plug

[Williboy]

Hi All,
I haven't posted in way too long, ( marriage, house, kid ), but I still have the Ranchero!!! So my trouble started about 6 months ago, was running errands and the car started running rough. Pulled the plugs and the # 1 was a lump of coal. The others were dirty/used. Installed new plugs and off I went. Flash forward to last week and only a few hundred miles and it started running rough again. Pulled the plugs and #1 is fouled again!! The rest looked ok. Ran a compression test, 125-130 on all the cyl. Added a little oil and all jumped to 145-150. Vacuum gauge is showing 19-20 " at idle. So I'm thinking ignition??? Or is there something else I'm missing?? I'm running PertronicsII Any test I can do on the ignition system?? Or any other suggestions?? Any and all help is appreciated!!
Thanks,
Glen

 

[bubba22349]

Had this problem before on mine too in my case it as due to bad valve guides. It could also be from bad valve guide seals too, you can usually see the signs of bad seals if you have the valve cover off. They can be replaced with head still on the car if you use some care pistion is at TDC for the cylinder your changing them on and then use a small valve spring compressor to pull the keepers and retainer replace the seal and reinstall. Good luck

 

[wsa111]

Valve guides & seals are paramount to prevent oil contamination.
Oil consumption is probably rings not seated.

 

[Williboy]

I like the idea of valve seals/guides over rings. Wouldn't the compression wet/dry test help verify the rings? 130 / 150 with 5-10 cc of oil added.

I'll pull the valve cover off this weekend ( in between Santa and shopping) and take a look. Anything to look for on the seals?? How do I check the guides?

 

[bubba22349]

If your engine still used the original type seals (Umbrella) you would see missing seals, or pieces of the deteriated rubber seal laying on the top of the head, inside the base of the valve spring, and or in the bottom of the oil pan. On the the valve guides you would need to first remove the spring and then feel for excessive sideways play, at that point if you find they are too loose you would need to pull the head off to be able to fix them. Good luck

 

[hotrodguy]

Odds are it is rings the problem.

 

[Williboy]

Leak test blows!!!! on all cylinders!!!

So I pulled the plugs, pump 100psi in all cylinders at TDC and all 6 are blowing air out the valve cover vent, dipstick, and if I plug those, I get blow by from the carb and exhaust. I'm not running a leak down gauge, just straight airline from compressor. Am I doing something wrong or do I have the worlds most messed up motor???!!!

I'm off w/ the boy to the zoo and have a beer.......

 

[Williboy]

So after tearing apart the washing machine to work on the pump early this morning... I popped off the valve cover and the the valve seals have splits in them. I guess that would explain the oil. Before I change the seals, I need to know I'm not wasting my time on that when I have bigger issues or, on the other-hand, tearing apart a motor for something minor. So what the hell happened on my leakdown test? Should I start w/ removing the rocker and checking the guides. ( I saw a youtube vid that should a vac gauge fluttering 1", exactly like mine which they said was guides) And I guess I could do another leak down with the rocker off so all the valves are closed and it doesn't matter if it's at TDC. Or do I just take the head off and have it professionally checked and serviced.

I feel like I'm at a major crossroad here and don't want to go down the wrong path or have to double back. (aka spend MONEY!)

Thanks for any input.

 

[xctasy]

So what the heck happened on my leakdown test? Should I start w/ removing the rocker and checking the guides. ( I saw a youtube vid that should a vac gauge fluttering 1", exactly like mine which they said was guides) And I guess I could do another leak down with the rocker off so all the valves are closed and it doesn't matter if it's at TDC. Or do I just take the head off and have it professionally checked and serviced.

I feel like I'm at a major crossroad here and don't want to go down the wrong path or have to double back. (aka spend MONEY!)

Thanks for any input.

Don't be arfraid to double do. A poor leakdownbefore the split seals are replaced is not an excuse for performing a full requiem and rebirth.

Do what you can afford, and then regroup when you have funds. First, just fix the obvious using compressed air to pop the valve springs, and change the seals to new old stock versions of the orginal, then retest. That oughta get you ahead on blow by. I'd put in new springs and consider a new timing chain. Then retest the static leakdown with over night or 8 hour test pressures


When the rings show too much blow buy (with the static leak down less than 85%), then its time to consider if its worth a rebuild.

Let me tell you something, the little 200 is hell for stout if the timing chain isn't causing the camshaft to get close to the pistons skirts. If your racing it over 4500 rpm, then it might have positive contact, and blow the skirts via conrod to camshaft contact (this is common on really extended, fogged within an inch of its life engine as the US 200 and 250 are interferance rod to cam and piston skirts when the timing chain streatch is large). Used within its normal capabilites, a high blow buy engine with even an 80 to 78% leakdown can still last for years, and be heaps of fun to tool around in. So fix the seals, then do a little more investigation. Springs and timing chain and maybee an exchange rebonded 200 balancer might set you back a little, but the engine is strong, and even when the bores are worn, then engine won't break ring lands or cause trouble unless its over reved into the 5000's. These are good little engines, so burn into the essential heart of steel for a few more years and plan a rebuilt or exchanged or pre loved low mileage block only when you have to.

 

[Williboy]

Thanks Ectaxy for the common sense/logical words of wisdom. ( I owe you a Monteith's Summer Ale!!)

I'm going to start w/ the seals and get a dial indicator to check the guides. The motor only has 20K + miles since a major rebuild, so I'm thinking nothing "should" be worn out. I'm going to dig out all my receipts and notes to see what was installed. I'll also pick up a leakdown tester and give that a try while messing w/n the head.

What's a good valve seal brand? I grew up when Felpro was the only gasket to use, but things have changed and improved.

Thanks

 

[Williboy]

So I was able to run some test.

Bought a Harbor Freight Leak Down Tester. It was showing around 20% leakdown ( in the Green "Good " scale). But it was only testing w/ 15 psi. So I did a little reading on the internet and swapped out gauges and was then able to run test at 50, 60 & 80 psi. All cylinders came back around the same at 90-95%.

So then I checked my valve guides w/ a dial indicator. I'm getting around .003 - .004 play on most valves ( # 1, 2 & 5 ). According to my book, the stem to guide clearance is: Intake .0008 - .0025, Exhaust .0010 = .0027. Is that the right specs?? Is that total or per side?? (.004 /2 = .002) I was checking with the spring off and the valve opened 1/2" or so.

Thanks