Change timing gears without loosening or pulling the oil pan?

[timk225]

I've got my 1973 Duster running and driveable, but it needs a little more tuning. I need to get some pin drills and clean out the accelerator pump tube in the Holley 1920, the pump shot is weak even when freshly rebuilt. One thing I think it might need is a new double roller timing gear / chain set. The 225 runs okay, but doesn't seem to have the power it should, or maybe I'm just used to driving my Tesla Model 3 for nearly 7 years.

Either way, if the stock gears are the plastic coated ones (are they?), chances are that 52 year old plastic will fall apart, and either jump a tooth or at the least retard the cam from chain slack.

I wouldn't mind pulling the radiator, harmonic balancer, and timing chain cover for a chain / gear swap, but with the locating pins at the bottom, how much hassle will this be? I would be doing it in the car and don't want to take the oil pan loose at all. I'm thinking that even fully unbolted, I won't be able to easily get the timing cover off with those 2 pins holding it in place.

How hard will this be to do? If I were pulling the engine it would be no problem, but I am not.

 

[halfafish]

Haha. Your slant will NEVER perform like a Tesla.

If it was me I'd just pull the engine. I can't see getting a good seal again on the timing cover if leaving the pan installed. It would be awkward as hell to degree the new timing set too. One of the gurus might have tricks to do this but to me it looks like an exercise in frustration to do it in-frame.

If you do this get a Rollmaster timing set. Spendy but well worth it.

 

[Charrlie_S]

It can be done, but it is a pain in the butt. Need to be real careful the passenger side front corner doesn't leak. Also as stated it is hard to degree the cam (highly recommended) while in the car. I have never run the "rollmaster/JP" timing set, but other slanters have reported alignment problems. (see this video ). I have run "stock type" timing sets (older style, not the newer ones with the slot in the cam sprocket instead of a hole) with no problems, or the older Cloyes double roller sets.

 

[slantsixdan]

One thing I think it might need is a new double roller timing gear / chain set.

Maybe or not—best check, rather than guess. Checking is easy: pop off the distributor cap. Turn the engine clockwise with the fan and belt until the timing mark is at the clockwise-most mark on the timing indicator tab. Then see how many degrees you can turn the engine anticlockwise before the rotor starts to move. That will tell you if you've got a slack timing chain, and if so, how slack it is.

Either way, if the stock gears are the plastic coated ones (are they?)

If it's got the factory camshaft sprocket, yes, it's nylon over aluminum.

chances are that 52 year old plastic will fall apart

Nope. They hold up quite well. They don't just fall apart because old. If you want to change the timing chain and sprockets, go ahead, but nylon-over-aluminum cam sprockets falling apart isn't a real thing to fret about.

I wouldn't mind pulling the radiator, harmonic balancer, and timing chain cover for a chain / gear swap, but with the locating pins at the bottom, how much hassle will this be?

Large, even if you don't do it outside in the driveway in the snow in the dark on a school night, as I did decades ago as a foolish-but-certain teenager.

I would be doing it in the car and don't want to take the oil pan loose at all.

You will be exposing the "Bermuda Triangle" of the Slant-6 engine, the junction of the front and right oil pan gaskets. This area is very difficult to seal successfully even with all-new gaskets, everything all squeaky-clean, and plenty of room to work unhindered. Without those advantages, you're just about sunk before you even start.

Also keep in mind that just slapping on a new T-chain and sprockets and lining up the dots is the wrong way to do it. You need to degree-in the camshaft, because the dots just aren't reliable.

I'm thinking that even fully unbolted, I won't be able to easily get the timing cover off with those 2 pins holding it in place.

Listen to that little voice in your head going "H'mm, maybe this isn't such a hot idea". Heed its wisdom.

The 225 runs okay, but doesn't seem to have the power it should

Well, be careful with those pin drills; every passage in the carburetor is the size it's meant to be, and drills—even wielded carefully—can be implements of destruction. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads (including a lot about the Holley 1920) are posted here for free download. Tune-up parts and technique suggestions in this post.

Bypass your OSAC valve, that's the dingus on the right side of the firewall; just run the distributor vacuum hose directly from carburetor to distributor. That right there will greatly spiff up the driveability and performance. Deviate from the factory timing setting of TDC; if it pings at 5° BTDC, back off to 2-1/2° BTDC. Place a BB in the vacuum line to the EGR valve (or just remove the hose from the valve and plug the end of the hose); that'll put a further spring in the step of the car.

Consider the HEI upgrade , which'll help some more.

 

[slantsixdan]

Haha. Your slant will NEVER perform like a Tesla.

Wull, I mean, yeah. His Slant-6 car will carry on doing everything it was designed to do even after the manufacturer decides to stop supporting it. His Slant-6 car isn't spying on him. His Slant-6 car won't have features and functions suddenly removed if he posts something on social media that the CEO of Chrysler doesn't like. His Slant-6 car won't pretend-full-self-drive into a pedestrian. Or another car. Or a truck. Or a wall.

I could go on, bet.

 

[halfafish]

Wull, I mean, yeah. His Slant-6 car will carry on doing everything it was designed to do even after the manufacturer decides to stop supporting it. His Slant-6 car isn't spying on him. His Slant-6 car won't have features and functions suddenly removed if he posts something on social media that the CEO of Chrysler doesn't like. His Slant-6 car won't pretend-full-self-drive into a pedestrian. Or another car. Or a truck. Or a wall.

I could go on, bet.

Couldn't agree more. I'd take a slant over a Tesla every time

 

[RustyRatRod]

Haha. Your slant will NEVER perform like a Tesla.

If it was me I'd just pull the engine. I can't see getting a good seal again on the timing cover if leaving the pan installed. It would be awkward as hell to degree the new timing set too. One of the gurus might have tricks to do this but to me it looks like an exercise in frustration to do it in-frame.

If you do this get a Rollmaster timing set. Spendy but well worth it.

This ^^^^^ Pulling the engine is the easiest way to do a good job. The engine is designed to remove the oil pan to get the timing cover off. That's how it's done. Just because joe blow says he's been doin it without pan removal for forty years, doesn't make it right. What you will end up with is an engine that leaks like the Exxon Valdez. Pull it and do it right.

 

[RustyRatRod]

Wull, I mean, yeah. His Slant-6 car will carry on doing everything it was designed to do even after the manufacturer decides to stop supporting it. His Slant-6 car isn't spying on him. His Slant-6 car won't have features and functions suddenly removed if he posts something on social media that the CEO of Chrysler doesn't like. His Slant-6 car won't pretend-full-self-drive into a pedestrian. Or another car. Or a truck. Or a wall.

I could go on, bet.

 

[Demonracer]

My thoughts are, pull the engine and replace the pan gasket along with the timing components and cover gasket. That way you can see what might be in the pan and you can give the bottom side of your slant a good once over. This will also eliminate a possible oil leak later on.

 

[timk225]

Yes, I'll check the distributor motion / timing mark as was suggested. I'll save the timing cover pulling for if and when the engine gets pulled entirely for more work.

I have thought about having an old time Slant 6 driving day, where I go in the car, leave the cell phone and atm card at home. I become untrackable (except for license plate scanners), just me, the car, and some cash. But if I break down with no cell phone, that could be inconvenient.

 

[RustyRatRod]

Yes, I'll check the distributor motion / timing mark as was suggested. I'll save the timing cover pulling for if and when the engine gets pulled entirely for more work.

I have thought about having an old time Slant 6 driving day, where I go in the car, leave the cell phone and atm card at home. I become untrackable (except for license plate scanners), just me, the car, and some cash. But if I break down with no cell phone, that could be inconvenient.

Yeah that's cool and all, but I never leave the house without my phone. You could have an accident, a medical emergency, you just never know. Lots in play besides old reliable. lol