Solve my rough-running Mystery, Please!

I really appreciate all the help I've received on this board in my quest to build and install a 200 in my 62 Comet. Well, the motor is in...I had a problem with temp and a rod hitting the pan, but those are fixed (new thermostat and pan). Now, however, the engine runs rough, lacks power, and slight knocking noise that correlates to rpms, but not in upper valve train. Here are the symptoms and what I've checked/done:

1. Hard starting...starts much easier when timing is over-advanced
2. Idles fairly smooth, although you can hear random but continual missing
3. When throttle is partly-opened, the knocking noise appears--not severe, but noticeable
4. When out on the street, car will sputter, lacks power, runs rough. However, it seems to be different each day. One day it seemed to run fine except for the noise. Next day, it sputtered too much to drive.

What I've done...Engine was redone with all new parts, except bearings and rings, which seemed ok, done about 30k ago.
1. Distributor, points, coil, wires all new. Timing set, dist installed correctly
2. Carb is good, even tried a second carb. Fuel pump new and good pressure

My next step is to possibly check for bad condenser, and also do a compression test. One mod I did make is that I put on a non-adjustable rocker set. The engine, when it was rebuilt earlier, had hydraulic lifters WITH adjustable rockers. One outside possibility is that the head may have been milled, and maybe I need to put the adjustables back on to get proper pre-load. Thanks!

it sounds like you dont have enough timing in the engine. its possible that the dampner has slipped and you are getting inaccurate readings with the timing light. i think once you solve your timing issue, the rest of the problems will go away, or at least be reduced.

If I remember correctly, the hydraulic lifters have 2.5mm of adjustment; if you had your head milled 0.060" (1.5240mm) that only leaves you with less than 1mm of adjustment. That being said, rockers that are way out of adjustment can cause excessive, premature wear on the valve train, and worst case scenario, a flattened cam (hopefully someone can back me up on that one). The noise you're describing in the bottom end could be the lifter bottoming out, but you'll definitely want to perform the other diagnostics that you have lined up; while you're at it, remove the valve cover and do the following:

1. Visually inspect the rocker assembly for damage.
2. Remove it and pull the pushrods and check for oval-ing of the ball ends.
3. Use a magnetic pick up tool to remove the lifters and inspect those for excessive wear.
4. Shine a light into the lifter bores and see if you can see any metal chips (tell-tale sign of a flattened cam).

I did the same thing: I have an Aussie 2V head that was milled, and went from adjustable rockers to non-adjustable rockers because the ball studs on the adjustable rockers kept backing off (they were just old and worn). I found some 0.060" thick washers (for a motorcycle) that came 3 to a package along with (3) 0.030" and (3) 0.015" thick washers (so I bought 2 packs and I used them to shim the rocker pedestals on the non-adjustable set). When I pulled the valve train components, I did find that the pushrod ends had oval-ed enough for me to notice the odd wear pattern visually, so I replaced the lifters with an extra set I had lying around, and swapped the ball and ball pushrods for the ball and cup. That worked fine until I got in contact with Gary from Rocker Arms Unlimited and bought some special lock nuts for the worn ball studs, and got the adjustable rockers reinstalled. I haven't had any problems with the rockers coming out of adjustment, and the valve train is nice and quiet. And that, my Brother, is about as much as I can help you... there are many others on here that know more than I may ever know, so hopefully someone else can chime in and give you some more valuable insight. The best thing you can do is take a lot of notes on what happens and when, and be extremely descriptive in your posts.

Thank you guys for the replies...keep them coming. To add to the replies so far, the damper should be ok--when I had the engine apart, I made sure the marks were right when piston was at tdc. I doubt that I would see any valve train wear, as all parts are new and have less that an hour on them. Everything SEEMED to be moving right in the train, but that doesn't mean the valves were closing correctly. I'll be checking condenser and compression tonight and report back. Sometime this week I'll try going back to adjustables. I've read that I should go to zero lash plus 1/4 turn for hydraulic lifters. All the "usual culprits" seem to be fine... this is frustrating...oh, wait, this is my relaxation hobby!

adamscm":3phzplex said:

Thank you guys for the replies...keep them coming. To add to the replies so far, the damper should be ok--when I had the engine apart, I made sure the marks were right when piston was at tdc. I doubt that I would see any valve train wear, as all parts are new and have less that an hour on them. Everything SEEMED to be moving right in the train, but that doesn't mean the valves were closing correctly. I'll be checking condenser and compression tonight and report back. Sometime this week I'll try going back to adjustables. I've read that I should go to zero lash plus 1/4 turn for hydraulic lifters. All the "usual culprits" seem to be fine... this is frustrating...oh, wait, this is my relaxation hobby!

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The visible wear that I cause on my valve train happened in only 30 minutes of running the motor. Also, you can use the "turning the pushrod" method, or you can use a stethoscope: with the motor up to operating temp and running, you can put the tip on the outside of the block at the site of each lifter bore and tighten until the you reach the lowest mechanical noise level on each lifter, it'll be perfect.

UPDATE: Suspecting the condenser, today I put in a new one, along with new points. The previous ones were new to the rebuilt distributor, but I tried it, and voila! No more hesitating or hard starting. HOWEVER, the fairly prominent tapping/banging noise remained, but only when accelerating. I disconnected the vacuum advance, and it went away. I checked the advance, and it seems to go way too far too fast. Now this wasn't General valve rattle you get with detonation, it sounds like one object making the noise. The fix, at least temporarily, is to find a way for the dist to not advance so far and so fast. I've already adjusted the dist spring posts to their tightest setting. I wish I could find some tighter springs. I think the idea of poor clearances due to non-adjustable rockers on a milled head may still be a culprit, and when advance is put on the engine, a lifter/valve bangs harder...just a theory, but I'll find out by replacing the adjustables. Worst case scenario right now is that at least I can drive it, it just doesn't have quite the "off the line" pep without the vac advance hooked up. Any other thoughts, please contribute!

What do you have your initial advance set to? Have you tried backing that off?

It's about 8. When I tried backing it off, it wouldn't idle well. That seems to be the minimum (if that's accurate) for my motor. The breaker plate/spring setup seems to be very loose on my high-quality $30 rebuilt distributor. I wonder if anyone makes tighter springs?

a kit w/ "Mr Gasket" is used to recurve sometimes. Don't have prt #s right now…

Here's a question for you guys---does anyone make a vacuum advance unit that is adjustable that will fit on a stock 65 distributor? I know later units were adjustable with an Allen wrench.

I bought a brand new electronic dist from AutoZone for I think about $40. It had the single pull vacuum advance which i hooked to an off idle vacuum source and bumped the timing up til it pinged then backed it off. Night and Day.

What motor was that for? Do you remember which distributor is was--Was it a Duraspark, and did you get other items with it, coil, voltage regulator?

Now you've got the location cited w/the post it may assist w/correct responses to the Q if U have the rest of the particulars there. This will mean the bottom of the distrub will fil and the carb will match the distrub. (ie - 144 is only '60 - '64 I think, SCV & LOM required, sm hole @ bottom/oil pump different dizzy/gear). I believe the other prts - wire coil etc are less important @ this point. To your Q I would simply respond "any ford6 1977 on,"

Update: After replacing the condenser, I still had too much advance, so I adjusted the distributor springs. Then, I put on my Holley 1940 carb that does NOT have a spark control valve. This makes the vacuum advance mostly due to rpms, not shooting up immediately when throttle is given like I was getting with the SCV. Car runs OK now. Just a bit of valve train tapping and an occasional miss. This week I will put the adjustable rocker set back on, which I think will improve the last remaining issues. This 200 sure does outperform the 144. I can actually accelerate uphill, and SmartCars are not passing me!

Plus the design of the 200 is "a square motor" meaning the bore and stroke are near equal length making it more able to accelerate in any gear (kinda like a motorcycle). It's a lill race motor while the 170 wuz like a tractor (to me). Like that so am going to the 250(no room or $ for the 300/4.9 & is a lill too heavy for the bronk).
You seem all set now?
Congrats!
NOW, enjoy drivin!

Recurve your load-o-matic distributor, it is fairly easy to do and it will work OK without a spark control valve. I rebuild flathead Ford V8's they used LOM distributors from 1949-1953 without a spark control valve. When you remove the cap and rotor there are two springs right on top of the breaker plate. The pins that those attach to are on an eccentric if you grab a hold of them with pliers you can rotate the pins either increasing or decreasing the spring tension and altering the advance. Usually there are two springs the lighter spring controls the rate of advance and the heavier spring controls the total advance. You can make small adjustments and recheck with a timing light and a tachometer. I have a Sun 504 machine and I still recurve LOM distributors on the engine, it is the most accurate way as every engines tends to have a different vacuum signal, especially a modified one.

For your valvetrain noise, the motors manual gives an excellent procedure for checking the lifter pre-load, however the lifters must be bled down to do so. With the lifter bled down press down on the back of the rocker arm directly above the pushrod and measure the gap between the valve tip and rocker arm face, you should have between .080 and .130. Less then that means too much lifter pre-load. You can either use adjustable rocker arms or Elgin industries makes shorter pushrods in .015 and .030 increments.

Thanks for all the posts. I'm still fine-tuning everything--did valve adjustment last night, but it's running pretty well. Had to go out and 'prowl the streets' with the 200 last night...yeah, I'm still rockin' a generator!

Prrrrrr-fect !
One of the few of us (least in my neck'a the North East) that doesn't have to do the cosmetics as well.
Lookin good!

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