Engine hesitation (1 Viewer)

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I'm taking a fork in the road. If that engine has any clean plugs (tan and not black), then I'd check the spark plug wire, and distributor cap, at #5 for continuity, zip up the distributor, and make sure that the valves on #5 are in spec.

what was your initial thought? Valve stem seal?
 

Dizzy

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You mean in like my post a while back?

Valve stem seal, maybe. Or, I have a head with a bent exhaust valve. It fractured the valve guide. Maybe the rocker was pushing down when combustion occurred?

Right now, I'm thinking that the exhaust valve might leave too much in the combustion chamber, or the intake isn't taking the full fuel charge. The electrical could be compromised by a bad ground on the head; there is significant rust on the exterior. On an aluminum head motor, I once had a loose plug, because there was too much oily soil to get the plug seated properly. Now I clean everything with gasoline and compressed air, flashlights and q-tips.
 

Dizzy

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So, it has been a while since I've opened one, and mine is the later version, but, I think that the two side screws that hold the distributor cap in place, will let the breaker plate assembly out of the distributor housing.

As always, if you happen to pull the distributor housing up from the block when rotating it, assume that you have disengaged the distributor tang from the oil pump slot, and the engine lost lubrication. It is hard to see the housing position with the fenderwell on. Don't assume that the oil pump is spinning after tinkering around with the distributor clamp. Check back with Mud if you need help seating a distributor. Motors on other vehicles were engineered so that the oil pump is spun by the camshaft, making the distributor much easier to service by the novice and shade-tree type mechanics.

Just a tip. I've found it to be important that when you are working on neglected motors, you pull the plug, scrape the oily soil from the outside of the head, vacuum out and q-tip the junk. Then dip your plug in gasoline and use the plug to clean the threads on the head by installing it, removing it, cleaning it with a wire toothbrush, then repeat to get the plug to install with just the socket and an extension, aside from achieving the actual torque with a ratchet. This allows for quick inspection / plug reading, and it insures that the plug is seated with the proper torque.
 

FJ40Jim

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@FJ40Jim ...is this the correct one from the website? Or does that only fit an 81-87? If it's not the right one...how do I order the correct one?
Yes, the EGR block off plate fits 77-87 2F exh manifolds.

Stop disassembling the distributor.
Just do the quick test of the mechanical advance: twist the rotor in a CW direction, then let it snap back to the rest position. That is the advance springs doing their job.
 
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Yes, the EGR block off plate fits 77-87 2F exh manifolds.

Stop disassembling the distributor.
Just do the quick test of the mechanical advance: twist the rotor in a CW direction, then let it snap back to the rest position. That is the advance springs doing their job.

duh, I knew Jim would have the quick check.
 
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duh, I knew Jim would have the quick check.

If the weights were frozen would the spring check still technically snap the distributor back? Only verifying the springs are there and operating, but perhaps the centrifugal weights aren’t free moving allowing advance? Could any sort of corrosion or drag alter the performance/resistance of the spring effecting overall timing? Almost like recurving the distributor by changing weights and springs? I know in my experience just because it works doesn’t mean it works correctly.. my thought is that because he can’t get timing adjusted properly there may be corrosion in the weight bearing shafts now allowing them to fully retract with the spring, causing him to adjust timing out of spec for idle (which he mentioned) which in turn takes it out of spec off idle for bad performance.

Just curious if my thought process is correct and worth digging a little deeper and the distributor may actually be worth taking apart. After all he did say it say for many many years.
 
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Sorry Jim...I'm talking about this: EGR threaded plug

Here is a video of turning it CW...is this working correctly? For the record, I'm not sure what the timing is because the BB is down and to the left just to get the engine to start...it's not in the left corner of the window...it's further out of sight.

 
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As always, if you happen to pull the distributor housing up from the block when rotating it, assume that you have disengaged the distributor tang from the oil pump slot, and the engine lost lubrication. It is hard to see the housing position with the fenderwell on. Don't assume that the oil pump is spinning after tinkering around with the distributor clamp. Check back with Mud if you need help seating a distributor. Motors on other vehicles were engineered so that the oil pump is spun by the camshaft, making the distributor much easier to service by the novice and shade-tree type mechanics. I haven't loosened the distributor screw and it's on there pretty good...is there still a concern the dizzy can become unseated?

Just a tip. I've found it to be important that when you are working on neglected motors, you pull the plug, scrape the oily soil from the outside of the head, vacuum out and q-tip the junk. Then dip your plug in gasoline and use the plug to clean the threads on the head by installing it, removing it, cleaning it with a wire toothbrush, then repeat to get the plug to install with just the socket and an extension, aside from achieving the actual torque with a ratchet. This allows for quick inspection / plug reading, and it insures that the plug is seated with the proper torque. This is pretty much how mine is...there isn't a lot of dirt/crap around the plug and I can twist it on and off with my hand until just a slight torque to tighten.
 

Dizzy

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The distributor clamp has two screws, one on the block, and one on the cylindrical portion of the housing. As long as either of these have not moved, then you are good. But, at least at some point down the road, it would be good to know the ins and outs of this. A quarter-inch too high, and you can ruin crank bearings within minutes.

Do you have a functioning oil pressure gauge on the dash?

They sell timing lights that have an adjustment on the back to determine how much advance you have outside of the window. Mine is a cheap south east Asian one from a chain retailer. If your light has this feature, make sure that you are accounting for the adjustment, or make sure that it is at zero degrees.
 

FJ40Jim

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If the weights were frozen would the spring check still technically snap the distributor back? Only verifying the springs are there and operating, but perhaps the centrifugal weights aren’t free moving allowing advance? Could any sort of corrosion or drag alter the performance/resistance of the spring effecting overall timing? Almost like recurving the distributor by changing weights and springs? I know in my experience just because it works doesn’t mean it works correctly.. my thought is that because he can’t get timing adjusted properly there may be corrosion in the weight bearing shafts now allowing them to fully retract with the spring, causing him to adjust timing out of spec for idle (which he mentioned) which in turn takes it out of spec off idle for bad performance.

Just curious if my thought process is correct and worth digging a little deeper and the distributor may actually be worth taking apart. After all he did say it say for many many years.
When the governor shaft seizes from sitting, the weights are not able to move. Eventually, the weights might also freeze. It is the governor shaft that gets stuck first.
 
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@FJ40Jim - where you able to see post #87? Couple questions there for you.

@Dizzy - Do you have a functioning oil pressure gauge on the dash? Yes. I'll have to check my timing light...I think I have a readout on there too.
 

FJ40Jim

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@FJ40Jim - where you able to see post #87? Couple questions there for you.
The threaded plug shown on the TLC performance.com site is sized for the larger 81-87 EGR tube. The correct size can be machined for the 79-80 EGR connection. It's not listed on the site because of very little demand, but the material & drawings are ready to go.

Didn't watch video, but if rotor can be turned CW and then snaps back, then centrifugal advance is working good enough.
 
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I think @rsnellie is on to something. Take a look at both videos, the plate has a lot of resistance when I try to spin it. The springs don't seem to b right...one is tight and seems to work correctly (the first one in the video), the other spring is loose and doesn't spring that weight anywhere. Not to mention there were 2 random washers in there just sitting there.


 
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Got the dizzy buttoned up. Video is the movement now...looks and acts better. Can't get it started though, and get a big back fire from the carb area...scared the s*** out of me when it happens. I think I need to retard the dizzy a little more to get it started? Any idea what that backfire is? Or, getting it started? Oh and I installed the carb spacer/gasket from City Racer.

Fuel pump came in today...will install it tomorrow.

 
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You have now fixed the advance and will need to reset timing to be correct with factory spec (not set to compensate for the incorrect advance). rotate engine to 7 btdc and verify the rotor is pointing to the bolt just above on the pushrod cover. then rotate distributor where points just open. Which you already know because you have the manual.
 

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