Hello,

I am new to this forum and new to the slant 6 engine. A few weeks ago I bought a beautiful 1976 Plymouth Valiant, pictures to come.

Part 1: I rebuilt the carb and am now having issues. I connected a few lines in the engine that wern't connected...replaced some hoses and now the engine dies around sharp corners and surges at high (60mph) speeds. Does anyone know what my issue is?

Part 2: Last week I bought a complete slant 6 engine with transmission and carb from a guy who claimed it work, compression test will prove this. I got a screaming deal and just couldn't pass it up. My question is the engine is from a 1972 Duster, my rig is a 1796 Valiant. Is my engine better or worse then that of the Duster? They seem to be very simliar. I'm open to any advise you all have.

Thanks,
Joe

The motors will interchange even if yours is a 1796 (I assumed you have a 1976)


Richard

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Part of Tyrde-Browne Racing

Please do post some. Pictures of slant sixes are like crack cocaine to us folks around here.
Could be several things. Dying around corners is usually indicative of a misadjusted float. Surging at high speeds could be an incorrect gasket, crud clogging a passage, an ignition problem, a vacuum leak, or something else entirely. I strongly recommend you read the applicable information mentioned in THIS thread.
Assuming both motors are still in stock unmolested condition, unless the 1972 engine is a 198 cubic inch displacement motor rather than the more common 225 cubic inch displacement, the 1972 motor will be nigh in identical to your 1976 motor. If the 1972 motor is a 198, I recommend keeping the 225. I recommend getting your 1976 motor running correctly before you investigate swapping motors, an expensive and time consuming proposition.

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Casually looking for a Clifford hyperpak intake for cheap.

Hi 76 Valiant, and welcome to the forum. The cylinder heads are different on a '72 and a '76, the older heads have different spark plugs, set in spark plug tubes, than the newer 'peanut' heads. Take a look at these charts from the 'article' secction, there you'll find the different engine component combinations up through the years. All red text in the forum are clickable links: http://www.slantsix.org/articles/parts-matrix/jpg.htm.

BTW; there's a LOT of other useful reading here besides all the articles, in each forum section you will find a 'Frequently Asked Questions' (FAQ), that will likely answer many questions, even without you having to ask them first! Have fun!

Olaf.

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Aspenized

<a href="http://tinypic.com?ref=e5r9d1" target="_blank"><img src="http://i55.tinypic.com/e5r9d1.jpg" border="0" alt="Image and video hosting by TinyPic"></a>

Holy crap , there's a slant six hiding under all that plumbing? The A/C sure does clutter things up.




Kevin

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crossthreads are better than locktite

What is the pulley in front of the ac compressor for? I would say it was a AIR injection pump, but I didn't think that those were put on A bodies. Yours must be a late production 76 model.

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Casually looking for a Clifford hyperpak intake for cheap.

The pulley on the front should be for the emmissions air pump.

Since you hooked up those vacuum tubes, I'm going to toss a WAG out there that something is mis-routed, or a component in the EGR system isn't working correctly.
Your having lean surge. What you need is the correct routing for the vacuum amplifier and associated EGR vacuum lines, and to check each of the system components.

The EGR valve should only open up when:

1) The engine is at full operating temperature.
2) The car is going down the road at cruise, not high throttle settings.

The EGR valve should be plumbed into the vacuum amplifer, the vacuum amplifier will have a hose going to manifold vacuum, and the temperature vacuum switch located in the top tank of the radiator.

EGR allows the ignitiion timing to advance beyond what would be acceptable without Exhaust Gas Recirculation.

Inspect all vacuum lines, use a Factory Service Manual to determine correct routing for all vacuum lines. This diagram can be found in other manuals, and I've found the diagram to be correct. (It's copied from the FSM.)

If the vacuum amplifier is not functioning correctly, you will need to find a replacement. This part is no longer available new. You may be able to find NOS parts, but it is more likely you will find it in a wrecking yard. Hopefully it is not defective. I have a couple different flavors in my collection of stuff. I don't know if they are working, or how long they would work once installed.

Make sure the EGR valve itself is in good shape. If it is being opened too early, when the engine is cold, or is open all the time, you will experience issues like this.

Reed pointed to the float level, and this is very important to get right. With too low a float level, you can experience lean surge at cruise.

This thread would be easier to read if you made the photo a bit smaller! The text ends up off the page.
Please take a look at the photo sizing guidlines in the "How to use this Message Board."

2¢

Guido

Oh, PS: The '74 engine isn't remarkably different from your engine, and uses many of the same components. Replacing an engine that needs a new vacuum hose would be a lot of work!

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☼

Sorry about the big pic...its easy to zoom in on my Droid. Guess I didn't consider what it would look like on a CPU. Yes there are a ton of hoses...Damn smog control.

Yeah, that's what the slant in my '78 Volare looked like when I bought it.
Not anymore, under the hood is much more "me friendly".

I agree with Guido about a vacuum line probably being in the wrong place. I did that years ago.

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

Wes,

What did you remove to make it more you friendly?

Joe

Pardon me if this has been said already:

The 72 motor may not have hardened valve seats for unleaded gas. The 76 one will. I would stick with the 76 head you have if you swap engines. Do compression tests on both and see which one is worn more.

Sam

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