Hello, Allpar Forums member or visitor! If you were a member, you would not see this ad!

Register or log in at the top right of the page...

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Advice on removing California Emissions from 225 slant 6

Discussion in 'Repairs, Maintenance, Help' started by CPaulson, Aug 21, 2017.

  1. AHBGuru

    AHBGuru Active Member

    Joined:
    Mar 22, 2015
    Messages:
    210
    Likes:
    89
    Absolutely. Poor tuning, a need for a carb kit, incorrect carb (common), wiring/vacuum hose problems due to age, heat, etc. Sensor failure or partial failure, fuel line or filter issues. Incorrect plugs or thermostat.

    It all comes down to proper diagnosis. Figure out first what the problem actually is, then figure out what is actually causing it.

    Even if it's the SCC, remanufactured replacements are very affordable.
     
    #21 AHBGuru, Aug 25, 2017
    Last edited: Aug 25, 2017
  2. dana44

    Ad-Free Member

    Joined:
    Jun 17, 2002
    Messages:
    19,343
    Likes:
    1,249
    I can agree that a well tuned system is always best, and about ten years ago I went through the diagnostics of the Lean Burn system on an '81 Ramcharger. After doing a couple hours of following wires, checking resistance, verifying sensors, ad nauseum, it came down to replacing the spark control monster on the air cleaner. Yeah, they don't make them any more so that was a waste of time I will never get back. The carb and the distributor are all part of a massive system, that yes, I will agree are fantastic when they do work, 18:1 air/fuel ratio at cruise is amazing and all that, and if the system works then keep it, and if it doesn't, scrap it, it is not even Commodore 64 technology so don't waste time trying to fix it, you can't.
    Solution requires both carb and ignition system and you will have a fine running vehicle, slant 6s are known for durability. It is too bad they didn't have MPFI for this engine, would be worth the swap, they are that good of an engine.
     
    Bob Lincoln and AHBGuru like this.
  3. AHBGuru

    AHBGuru Active Member

    Joined:
    Mar 22, 2015
    Messages:
    210
    Likes:
    89

    That's the bear of it. They had 99 million different calibrations, with 99 million SCC's. On the later cars (M-bodies), they superceded everything down to just a few part numbers from the '89 MY, since there was little change between '85 through '89. Older stuff using the TQ and BBD is very hit and miss. A fella might luck out using a SCC for a similar application, but many of the pre-'80 part numbers are simply not serviced. Then you're stuck using the equivalent non-feedback carb and ignition. Even then, a good rebuilt TQ or BBD will provide the best results over the overhyped Eddy and Holley carbs (I'm talking street use).

    As for the Leaning Tower of Power, a high school classmate once owned a '76 Valiant coupe that had a small 4-bbl of some sort. I think it was a trick intake. Maybe not the power of the E58 Dodge I had at the time, but it was still a blast !!!
     
  4. CPaulson

    CPaulson New Member

    Joined:
    Aug 21, 2017
    Messages:
    5
    Likes:
    2
    Thanks for the advice folks. Turns out my problems with the engine go deeper than the emissions set up. Put it back together and the timing is way off and still leaking. Head is bad. So I got a 318 and now I'm looking to drop that in. Even though the engine is coming out of a 79 Dodge with a 727 I'm told the bolt pattern is different so I'm going down that rabbit hole now. And thank you call again.
     
  5. KOG

    KOG KOG
    Level 2 Supporter

    Joined:
    Jan 8, 2003
    Messages:
    6,515
    Likes:
    217
    Good move. /6 is a fine engine, just not big enough to be very useful in a P/U. 318 727s are very plentiful. 360 ones will work fine too, but must have 318 converter.
     
  6. SlantSixDan

    SlantSixDan Member

    Joined:
    Mar 8, 2012
    Messages:
    4
    Likes:
    1
    1975 and newer gasoline-powered vehicles are subject to the requirements of California's Smog Check program, which includes rigorous inspection to make sure all original (or approved replacement) emissions equipment is intact and working.

    That is exactly what they did.

    That is not correct. The same piston is used in all Slant-6 engines from the first one built in 1959 to the last one in 1987, except for some engines intended for export which got special pistons for very low (7:1) compression to cope with very low octane fuels in certain countries at certain times. And the combustion chamber shape on the Slant-6 changed exactly once: it was revised slightly in 1967 to eliminate a small dead zone and provide more complete combustion. It was not changed again.

    True, the 1981-up hydraulic-lifter camshaft has different specs than the '71-'80, '65-'70, or '60-'64 mechanical-lifter camshaft. However, the specs on the '81-up cam aren't as different to the previous solid cams as the raw numbers appear.

    The distributor has no mechanical or vacuum advance mechanisms. Spark advance is controlled by the computer, which may be labelled "Electronic Spark Control" or "Electronic Lean Burn" and is found hanging off the side of the air cleaner housing or tucked into the left front fender.

    That is true.

    Nope. There is no reason why the intake manifold would have to be swapped, even if the owner were to want to remove all emission controls. 1973-up intake manifolds have provisions for an EGR valve, but this is readily blocked off by any of several means (including simply not hooking the EGR valve up to a vacuum source) if it is not needed because a later intake is being used on a pre-1973 application that doesn't require EGR.

    If the original poster were to want to keep the Slant-6, he should get on slantsix.org and post his questions there, where he'll get knowledgeable answers and direct help, without being sent on goose chases. If the owner's going ahead with the engine swap, he'll want to carefully check the applicable laws and requirements for such swaps. For example, in California and some other states the engine may not be from an earlier model year than the vehicle it's being swapped into, and all emissions-related equipment appropriate to the vehicle and/or the engine must be present, correctly configured, and functional. See here for California's regs.
     
    Bob Lincoln likes this.

Share This Page

Loading...