The Stovebolt Site Forums The Shop Area Engine Shop 235 break in questions..

Hey guys,

My 235 now has about 140 miles on it. Its running very well, but still smoking somewhat. I'm driving it around town, cruising at about 2000 RPM and staying off the interstate. Anything I can do to help the plasma-moly rings seat properly?

I changed the oil this weekend. Didn't see any metal. But when I emptied the drain pan, there was a little bit of moisture in the oil, like some antifreeze had gotten into the crankcase. It was only maybe an ounce or two... Should I be concerned? Retorque the head gasket or drive it or what? Engine runs cool and has 30 PSI oil pressure hot.

thanks
chip

My 235 use to do the same thing. I figured it was moisture "condensation" from the road draft tube or the breather on the top of the valve cover.

It won`t hurt to re-torque the head.
The engine should be ran at varying rpm throughout the drives you take it on.
The first 283 I rebuilt in highschool smoked for a long time, not much but some. I ran the engine hard for about three years. I stopped in to a store to get something to drink and I was thinking I should check my oil,,,,,
I started talking to a real nice looking sweetheart and forgot all about the oil. About three miles or so out of town (115mph) I heard a faint rattle noise. Looked at the oil gauge and it was at "ZERO" I stopped, turned around and headed back to town for oil but the damage was done

OK, I figure I'll torque the bolts I can get to with the VC on, and if any of 'em budge I'll pull the VC and do 'em all. I guess I should be watching my water level, eh?

The motor seems to smoke at idle, out of both sides but more on driver's side. When I rev it up and let off I get a good puff of smoke, then it fades. While I had it apart I changed the valvestem seals, and I pulled and cleaned the valves. Only have 12K miles on valves and guides. Should I accellerate hard or easy as I go thru 1st and 2nd? Let the engine slow the car down to work rings?

thanks

chip

Don't put any strain on the motor but run it through varying RPM's throughout each ride. After every so many miles you can increase the top rpm.

I am keeping everything crossed at once on this one.

The smoking sounds like valve guides worn. Put some umbrella (**** ) style seals, on the valves to help stop that problem. If you ever do another ring job, use only plain steel rings. I know everyone has an idea about that, but I never had a motor use oil, that had them in it. I use them in my racing motors and run them full rpms, after about 20 minutes breakin time. There is an old time remedy to seat the rings, but I won't suggest it until you do the valve seals, first.

Chip, are you sure that's water and not gas? Could you have some blow-by from a ring that hasn't seated? I assume you checked compression repeatedly before firing it up, but have you done that recently?

Coolant leak - Did you put a stop leak, such as aluma-seal in the system? I've learned to do this on any new engine. Also not to put in antifreeze until I'm sure there are no leaks.

Seating rings - Get up to about 40 mph, then back off to about 20, and accelerate again. Up and down several times, full throttle to closed. This will help seat the rings. With stock rings this only takes a few times to seat, I don't know about your super-duper rings.

Hope you have your lucky rabbits foot in your pocket this time.

Fred is right, ring manfacturers recomend driving the vehicle immediately ,putting a load on the engine.I am no pro engine builder,but the several car/truck engines and many motor cycle engines I rebuilt, never smoked using the above technique, and using regular motor oil for the break in.The 261 I did a few years ago,has moly faced rings, the advantage of moly is supposed to be a fast break in and good ring seal.This engine never smoked even when first started.I always use umbrella seals on my 235/261 engines, the exact same ones used for replacements on small block V-8 Chevys.Your problem my be seals however if you are using only the o ring type.

Thanks for the suggestions. The strange thing is that I didn't notice the engine smoking like this on the last build that ran 100 miles. I didn't do anything to the head this time except clean it up and install new o-ring valvestem seals.

I'm running castrol 10W30. I'm going to retorque the head and keep an eye on the oil and water levels. I'll try the getting on/off the engine as suggested to seat rings. I'll post back and give an update.

thanks!

chip

Was on the south side of town today and stopped by my machinist. I asked him the same ques I posted above and this is what he said;

The moly rings shouldn't be smoking. The total seal rings seal off so good, the engine is sucking oil past the intake guides. He gave me 6 positive style seals and told me to change the o-rings out for them on the intakes. Hopefully they'll fit.

On the possible coolant seepage, he told me to re-torque the gasket while I had the valvetrain apart. He said I could use some "ceramic seal" in the cooling system to seal up any small leaks. The stuff forms a coating on the water jackets and seals off. Run it with straight water for two days, then drain system and let dry for a day, then go back with antifreeze. Should I try the ceramic seal or just re-torque?

thanks

chip

Chip,if you're running a higher lift than stock cam,it's a possibility the clearance between the top of the valve guide and valve spring retainer at maximum lift isn't enought to clear an umbrella type seal.At least it wasn't on my engines, I had to reduce the guide height by a 1/16 inch. Did it of course while the engine was diassembled.

The shop apologised for not catching this technical tid-bit. I had been running umbrella style seals with the clifford 260 cam, which has a higher lift than the M4F i'm running now. He gave me some positive type to use. However, the old umbrella seals were used with the stock retainers, I have a set of comp cams retainers now, so I hope I have enough room between retainer and guide for this type of seal.

For clearance, do I need just a little wider gap at full lift between retainer and guide than the thickness of the top of the seal?

thanks

chip

I installed umbrella seals on the intake valves. Its still smoking, but not quite as bad. I've been told its worse on the driver's side. Both pipes have oily residue in them.

Would the rings take longer to seat if the shop used too-fine a finish hone? In general, do rings in most engines eventually seat?

Did a compression test: All 6 holes were between 120-130 PSI.

chip

Curious,,, how much vacuum is this engine pulling?

At idle the engine is pulling about 15 or 16 inches of vacuum. About 20 on fast idle, I assume that or more while at cruising speed. The last engine pulled comparable vac numbers. M4F cam with 4 bbl and fentons.

The only other thing I can think of is that the top ring gap was on the high side. The clearance called for .016" on top ring, the actual was .021" or so. But still within spec. The 2nd ring was correct at .013" All rings were checked for gap clearance, and I'm pretty sure I got them installed rightside-up and staggered per instructions.

Basically should I continue to drive it, or park and figure out whats going on?

chip

Chip,
Are you sure you are not running too rich, enough to wash down the cylinder walls and make the rings leak?

I thought about that today... Would that show up when reading plugs?

Those of you with the M4F cam. What is your idle speed? My engine idles very rough/stalls under 600 RPM. Maybe I have the valves set too tight or a vac leak.

I drove the car to work yesterday. Seemed to smoke less when I got home.

It might. It did on my son's. Your total miles is still low, but if it's running super rich you might be able to catch it this early.

hmmmmm,,,,,, are there any fuel additives in the tank?
How old is the fuel in the tank?
What fuel are you running?
The vacuum readings look good by what you posted............
How is the coolant level?
What do the plugs look like?

Chiphead,
I have the M4F cam. To start with my cam is not set straight up as they say. I have the cam advanced 4 degrees with a cam key, I think I used the std chevy V8 keys you can get from Jegs or the local speed shop. It sucks a steady 21 inches of vac at about 650 rpm but will go lower. As for valve settings - the cam card says to set hot at .014 and .016, however on mine it sounds like the hammers of hell and I can visualize the valve stems turning into mushrooms. So I re set a few times and the 235 appears now to like .012 & .014 on what they call regular fuel. The tighter the valve settings will move the power band up and along with it the rpm. If you go the other way and leave at .014 & .016 the engine will have lots of low end torque and will better match a stock 4.11:1 rear or a 3.90:1. Both these valve settings will have associated timing and plug color changes. Your engine will run cooler with more valve seat time; example .014 to .016 (.016 setting will allow more heat transfer to the cooling system) Good Luck. I ended up with a 165 therm and it runs a steady 170 or less even on the hot muggy days.

I've got 15-16" of vac at 800 RPM hot. Vac drops way down at 600 RPM & idles like a harley. Powerband is good from about 1000-up. Runs cool, etc. I think a few of my valves are too tight. I didn't readjust the valves after I broke the valvetrain down and installed the umbrella seals on the intakes. Also retorqued the head.

Coolant level has not decreased last time I checked it hot. Fuel was old, but ran it down to 1/4" tank and refilled with fresh 93 octane Shell gasoline from a new, big station. Plugs looked nice & tan when I went to change stem seals and did compression test cold. I've got 3.55 gears from a '54 'Glide car, so I need the low end torque to move that 4 door boat. But she'll do about 50 at 2000 rpm.

I'll prolly reset valves to what '52 suggests, adjust timing and idle mixture and post back. Any other things I should look at?

thanks guys!

chip

Your valves are definately too tight.