My 230 Came Alive

As many of you know, I am living with the stock 230 until I collect the funds and parts to finish my BBC/NV4500 swap. I have always been very dissapointed with the performance of the six. Today, I was pulling a horse trailer and the engine woke up. I was going down a gentle grade trying to keep the truck up to 45 mph. I normally hope to maintain 30 going up the hill empty. I got to the bottom and the truck didn't slow down. I gave it some gas and I passed 3,000 rpm. That has never happened in fourth gear before empty, much less pulling a flat fronted trailer against the wind. I dropped off the trailer and was able to pull 50 mph up the hill. The engine was screaming and I was on the floor, nothing new about that, but the truck was actually running at near speed limit speeds. Here is the question. Why now? and just plain why?

I have not touched the engine in weeks, except to change the oil a few weeks ago. I took the carb apart to blow out some dirt a few months ago. The timing has been set at the specified advance for several years. Both the vacuum and the mechanical advance of the civilian distributor have worked for years. The plugs are old AC 45's that I cleaned up by hand and put in the truck to make it start three years ago. I think I have one, maybe two rocker arms that are just a hair away from not ticking anymore, the rest are set to spec. The exhaust is the stock manifold with a bailing wired on glass pack thing done by the DSPO. I have a GM internal regulated alternator and GM p/s pump on it. It has been there since mid summer though. I actually had to set the idle down 400 rpm when I got home. Obviously, the engine is working better but I can't explain why. I'm just looking for any plausable explanation. It bothers me that I can't figure it out, Thanks.

Did you accidentally hit the nitrous switch?

Really, I dunno, maybe you broke a big chunk of carbon loose and somehow sucked it thru the engine without having catastrophic failure.Does yours have the governor? It could have stuck open allowing free operation at high rpm?
I removed mine and noticed a difference in power, it also quit crapping out on me during wide open hill assaults.

Mine is a '67, no governor. One thing I forgot that you reminded me of. When I changed the oil, I forgot to put the cap back on the valve cover. I probably drove it 10 miles before I caught it. No mess or smell. Maybe I really did accidentally blow something out?

I've also had the distributor rotate if either of the hold downs are not tight. That will certainly change performance. I suppose it all depends on where it was before and where it rotated to. Might want to check that also.

Hey Tim,
Did you ever check the compression(previously)?Have you ever noticed it using any oil? Did it always run smooth and quiet(quiet as a 230 OHC :})Is it still starting up as normal?

Doug might have the right idea, I was kinda leaning towards maybe a valve problem?!?! Sticking or carbon? Your guess is as good as mine!

I advanced my dizzy once but it didn't like it.Gave it more power but spark knocked like crazy.

I've been adding Seafoam or Lucas fuel additive(Lucas rules!) to my fuel and it has really seemed to make it run and perform better.

Either way, with all that power, who needs a BBC now?!

-Ben

These things run about as smooth on 5 cylinders as they do on all 6. Mine was a turd one day last summer following a tune-up. Ran smooth, just cajone-less. When I got home, I popped the hood to find a spark plug wire off (I must have left it off when I removed the timing light). Ran noticeably better once I reattached it.

You may have had a bad plug or wire, or other ignition condition that cleared itself. Not to say it will stay cleared. If and when it resurfaces, pull oone plug wire at a time and watch for any changes in idle - this will point you to the one(s) that are hosed.

Good point Bump, They say our solid wires will never go bad. Wrong. I had to replace one that was causing intermittant problems.

Use a temp gun on all exhaust ports to verify they are burning.

My 230 gained some guts after I set the valve lash and poored a cup of water down the carb. It was running on pritty fearcly after I installed a radiator overflow and filled the radiator up. That caused it to run cold. The cause was a lack of a thermostat, fortunately I had saved and remembered saving the thermostat that I found rolling around the bed after I bought the truck. The truck now runs at 190F and the runon problem stopped after pooring the water down the carb.

Jeff

I never checked the compression or if every cylinder was firing. As I said, I'm just living with it until I swap it out. It was smooth though and still is. My valve lashing procedure has been to get it warm, shut it down, pull the cover, adjust and reassemble. I have one maybe two that are just barely tapping still. I haven't gone in to make the fine adjustment on what I think is the number six valves yet. I have not been motivated to do that recently. I'll get bored one day and make it perfect. My distibutor is still secured tightly and I checked my timing last night, right were I set it a long time ago. Thanks for the input, I am leaning toward the spark plug/wire theory.

if you use a temp gun the #1 and #6 will be about 100* cooler than the inner ones. Just from what I've seen, #1&#6 should be about 350*. #2-#5 will be about 450*. A reading of 250* shows that the cylinder is not firing. This will probably vary gresatly depending on the temp gun and where you aim it and how close you are to the point being checked.

I know that you checked dist. being tight, but remember that there is a bolt on the bottom of the housing that can (and does, trust me!) come loose. This is in addition to the regular one to adjust timing. When I get my timing just right, I set the "regular" or visible one at the center of the travel, then use the hidden one to establish this baseline.

I don't know what happened, but your motor is or was definitely not set up correctly.

The 230 is a strong engine that should push your M715 at 55 to 60 MPH all day long. It never lugs, providing good power from off idle all the way up to max RPM's. It should get you about 15 to 17 MPG.

I have never seen a civilian M715 with a 230 in truly good tune. This is the main reason they have a bad reputation - good motor, badly maintained usually.

If the timing is indeed correct, your compression is good, and your valves are set properly, you can spin the rear tires on any M715. The motor will wind up quick and strong no matter how much weight you have in the bed.

The old 230 is a simple yet dependable design that unfortunately, has suffered mightily at the hands of poor mechanics.

I agree. I think the 230 is a pretty impressive motor that has an undeserved reputation. I'm frankly amazed at how well a good running Tornado can haul one of these heavy trucks around.