350 - First Start - Alarmed
 

You all have shared advise for my 1968 Firebird cam swap and heads rebuilt. It’s been 15 years since my last engine job and in my mid sixties now so memory and strength has faded some….
Swapped a rough idle performance cam for a stock “066” cam to include Hy-lift Johnson lifters, rebuilt the heads with new valves, springs, and milled .020, using all Felpro gaskets throughout.
Set out today to perform the break in. It fired off amazingly fast and I brought it up to around 2,500 RPMs and held there for several minutes. Immediately there was a lot of smoke from both exhaust pipes.
Initially I’m thinking that’s the oils etc. from the machine shop and-or the coolant that drained into both head pipes when the heads were removed.
I ran it for maybe 3 minutes and the smoke didn’t clear so I aborted the attempt.
I pulled all the spark plugs and they all were dry. No dampness.
Would antifreeze that collected in the head pipes from the head removal create this smoke?
This happened about the time all the kids were home from school and I didn’t want to cause any parental concerns in the neighborhood. The wind unfortunately was blowing directly towards my house and I didn’t want smoke in the eve vents.

Mind spinning…….

Antifreeze burning has a very distinct smell and to me really can’t be confused with oil burning.

Oil burning is blueish. Antifreeze is white and smells sweet.

It might take 5 or more minutes of run time to burn out all of the antifreeze that got dumped into the exh system.

Thanks Steve. It’s a real quick “downer” to go from an instant startup to puffing smoke-steam. Maybe it wouldn’t have been as shocking if this was warm weather. I kept going over in my head “did I mess up the head gaskets” but I did speak with a Felpro technical person who said “there is no up or down” on the Felpro head gaskets I used. I reckon another attempt tomorrow or Friday. Thanks again.

Could be just condensation in the exhaust pipes and mufflers.

It’s probably pretty cold where you are.

Smoke or steam, which is it?

Steam would be normal, with water dripping out of the tailpipes.

Tomorrow drain all the coolant out and run it for 30 seconds, no you will not harm anything but if it still smokes then it’s not anything to do with head gaskets.

After doing this just don’t put any coolant back on for 20 minutes.

When i rebuilt my 389 a lot of coolant had gone into the exhaust. The new engine ran a long time with a lot of smoke coming out the exhaust. I also was worried. I shut it off a couple of times to check everything out. Eventually the smoke/steam disappeared. Don't give up hope yet.

While working in a Buick dealership I had occasion to head gasket dozens of 350 Buick engines due to premature deterioration of the fiber head gaskets Buick used.

By the time they were brought in for head gaskets they're had been pouring coolant into the exhaust for awhile. After completing the repairs, they belched steam out of the exhaust for 20-30 minutes. It takes awhile to turn all that coolant to steam. Knowing this I would say by the time you run it for 15 minutes you should see a huge reduction in the amount of steam. If it hasn't abated by 15 minutes of run time, you might be looking at some other problem.

Hope it all works out for you..........:thumbup:

How would you still have coolant in the exhaust manifolds? You typically remove the manifolds if the heads were sent to the machine shop for valve and machine work. You will typically get coolant spillage into the cylinders which you should remove with towels or a wet vac. The residual coolant that remains in the ring lands will cause a bit of initial smoke on startup but it clears up immediately.

Check your oil for antifreeze contamination. The obvious culprits are intake or head gasket leaks.

'parental concerns" ?? Invite all the kids over and fire that sucker up. it will stop smoking, they would love it.
I might shut a engine down to my own mechanical concerns. But never for some helicopter parent.
And I light mine up with open exhaust.
I am sure there a lots of hot rod engines fired up there in NASCAR country.

You're right to be wary, but I'd say it'll take considerably more than 3 minutes to cook all the condensation out of an exhaust system. And that's with a daily driver. Wouldn't a cold muffler act as a moisture trap until it's good and hot? If some folks in the neighborhood are going to wrinkle their noses, you can always run it after dark. Internet says sundown in NC is 5:26.

Life's too short to worry about what everyone else might be thinking. Heard a neighbor doing a compression test in the evening once, went over and offered a hand 'cause I though he had a no-start. He was concerned about the neighbors too. Told him the "noise" wasn't an issue and anyone that would call the cops need their head examined.

Head. Pipes. It's right there in the original post.

Yes I know I worry too much about what the neighbors think. Me and my wife are the “elderly couple” on our cul-de-sac. All the other households have school aged kids. There’s 13 kids out of the 8 houses on our street. I’ll fire it off today and see what happens. I tried again late yesterday and lost my spark. I may be replacing coil, module, etc. in this GM HEI. Looking for a step by step test scenario now….

Just for reference you should never crank over a powered up HEI if you have the plugs not hooked up.

“Check your oil for antifreeze contamination. The obvious culprits are intake or head gasket leaks.”

No way for an intake manifold gasket to cause this issue on a Pontiac.

I cannot see coolant going into the chamber, more so the situation would be combustion pressure to the cooling system.

It’s most likely Residual coolant, oil on guides from install, the anti corrosion spay from the machine shop, and the normal moisture condensating from the exhaust…amplified visibility on a cold day. Keep an eye on the cooling system….and

Run It!
✌🏼

Drop the pipes off the manifolds and start it for a minute see if it’s still huffing smoke.

Ok guys. I’ll report back later today. I’m too old to cry but if I have to take this apart all over again I just might….

After it sits a bit, and before you continue, it would also be a good idea to pull the drain plug out of the oil pan for a bit and make sure no coolant in the crankcase.

I think I would do pressure test on the coolant system. I think you can get the pressure tester from O'reilly's. Could rule out a gasket leak pretty quik.
Also pull the dipstick and make sure you only see oil on it.

I have had engines take 1/2 hour, sometimes a little more, to stop "smoking/steaming" after an engine change or fresh rebuild. Depends mostly on what was in the exhaust system when the engine failed and removed. Also, how long the car has been sitting. I would monitor the engine temp, make sure there isn't excessive pressure in the cooling system, and check the color and smell of what's coming out of the tailpipes. Regular water, steam, out the exhaust will leave the tailpipe, (s), and rise up and over the back of the car and dissipate into the atmosphere. Coolant in the exhaust will leave the tailpipe, (s) and stay low, gathering a cloud near the ground and engulfing the rear of the car. It generally has a slight gray color to it and the sweet syrup smell others have mentioned. I would run it and observe much longer before pushing the panic button.

Didn’t notice anyone make this suggestion but it would be the first thing I’d do is check the coolant level and see if it’s gone down any. If your down coolant your probably burning it

My old 48 year old coolant pressure tester is now junk. I’ve ordered a new one through Amazon that’s supposed to be here in the morning. That will tell the story. My stinking heater core is leaking so I’ll by pass that for now until the break in.

Some. Found that the heater core is leaking. This thing is fighting me!

The HEI was not getting 12 volts. Found a previous “repair” that was a poor connection where there was a splice. I’ve repaired that so ignition is back in operating condition. It has failed to fire off a couple of times prior to this and would mysteriously be ok when I’ve traced wires before. Maybe this Artic weather helped in that regard.

There could be residual coolant in the exhaust system but I wouldn't bet on that if large amounts of white smoke are still present after the motor has warmed up as the OP says.

I still do not get how you would spill antifreeze into the headpipes while pulling the cylinder head. I mean, come on, do you hold the cylinder up like a trophy letting antifreeze pour everywhere after removing the head? Every head gasket change or head swap I've ever done barely dripped antifreeze on the garage floor. The minute you "break the seal" of the head gasket by rocking the heads up from the intake port side, a small amount of coolant goes into the cylinders and coolant spillage is contained by the weight of the head resting on edge on the head gasket as you rotate it up.

Again, it may just be a fluke, but I would be checking the oil for coolant contamination. Also, if improperly torqued intake or head gasket can create an internal leak from one of the crossover passages into an intake port or directly into a cylinder and siphon enough coolant to make the exhaust a smoke machine. The presence of plugs that appear "Steam cleaned" compared to the other normal carboned plugs is your clue.

On heads that I have had off before and removed and the removed the exhaust manifolds if I had to pull the heads again I would first remove the exhaust manifolds to save some weight and gain some more clearance on humping the heads over the fender and out.
Doing such makes it easy to get coolant from the rear of the head down into the head pipes if you do not have the block drained far enough.

Got my cooling system pressure tester this morning. Tested the system - no leaks. Fired up the engine and kept it between 2,000 & 2,800 for 12 minutes until it got to 200 degrees. All the smoking stopped after 5 minutes. Relieved. I know now I need a fan clutch. This one never seemed to engage even after the higher temps. The plan is to replace the fan clutch, pull in a smidge more timing, and go at it again for another 25 minutes or so. Sounded a lot more crisp and responsive. I reckon all the machine oil in the heads and antifreeze that wept out of the block after the heads were removed went straight in my head pipes. They hung in the position exactly where they connect to the exhaust manifolds. I have robust exhaust hangers. Anyway, small strides.

Good news to hear.

Is the Hayden 2747 clutch a good replacement? I can’t remember the modification we used to do at the Chevy dealership regarding the thermal spring. Is it putting more tension by rotating the spring as shown?
https://forums.maxperformanceinc.com...8&d=1594336603

2747 is the right one but not the mod - you want to read this thread:
https://forums.maxperformanceinc.com...ht=2747&page=2

especially the bench testing done by mgarblik in post #31: https://forums.maxperformanceinc.com...9&postcount=31

https://youtu.be/oSexUZHcmZ4?si=X6PCQYriNXlxfmJu

I did a little video on that a while ago with a couple different ways to modify the spring based on the type of clutch you have based on scanning a bunch of different old threads. But yeah the easiest way is to just bend it a little.

Nice job on the video. :clap2: Thanks for posting that.

Yes, nice video, and so very important you have a good clean vocal delivery, you don't go off on tangents, you don't tell us what your cat did today, or what you had for lunch :)
And nice camera work too.

Thank you. Its a hobby. The work in front of the camera is fun. The editing is brutal. I have like 4-5 videos just sitting on my computer that I've been dragging my feet on editing. Ive actually been meaning to make a speed edit of that one that takes out the stuff about selecting the right clutch to just get it down to 3-5 minutes of only the test results and spring bending.

I recently bought a real camera instead of a Gopro, so it gets rid of some of the annoying glare problems I had from my ceiling lights.

I probably should post links to a few more videos on here from time to time, since some of the stuff I've done is just consolidating little bits of info from years of forum threads that would be helpful to the pontiac crowd, but I get self conscience about it. Feels like begging for views.

Speaking of tangents, funny story. I tried to build a cheap DIY temp chamber for that test, but it was an abject failure. I got it up to like 300* reading on a cheap oven temp gauge. But the clutch spring didn't move. I suspect because the hot air flow was just sort of ambient rather than blowing directly on the spring as it would through a radiator. Eventually it melted the lid I was using.

Good video, I learned something here.

Nice video. I’ve ordered the Hayden 2747 clutch and will modify the spring as shown. I recall my sister’s 1970 Grand Prix whistling and I always thought it was that heavy duty fan clutch, big fan, and “half of a 55 gallon barrel” for a fan shroud. I don’t care if it creates some noise as long as it’s cooling. Thanks everyone.

Good to hear the smoking was just residual coolant/oils.

Just to mention this, if youve already ran it at 2000-2800 rpm for 12 minutes, you dont need to go another 25 minutes... cam break ins are usually 15-20 minutes at ~2000, never heard of almost 3000 rpm but im sure it wont hurt. Either way you probably only need to go another maybe 10-12-15 minutes and the cam will be fully broken in.

what a helpful video 👍

PonntiacHO- Another happy ending! Glad you stuck with it and got the help you needed. That would have been upsetting to see a cloud like that after all the work you did, so hope it built some confidence.

RocktymusPryme- The clutch adjustment video is excellent. Very well done and informative! You are good at this. I hope you open a thread on this forum and post links to your content as you release them on Youtube. Helping us is not shameless self-promotion IMO, it is why some of us follow this forum.

Mike

Great video...I'll echo what others have said...more please.

Agreed- video is very helpful and you have a knack for teaching!

That modification was one of those things, I vaguely remembered was possible, no idea how exactly to do, and knew that I probably would have to do it someday.

So yeah, kudos on the subject matter, it was genuinely useful.

Finished the break in process (another 20 minutes). The engine temp stayed at 180 consistently. The new fan clutch (with modification) definitely did the trick. Changed the oil and filter and was going to do any adjustments necessary but it sounded like a healthy Pontiac from. back in the day. Went to fire it off and….no fire. I ordered a new Cardone HEI from Rockauto. It seems to be well made. The module has a Delco part number on it. The cap has brass lugs. Seems ok. Yes it’s an offshore product but maybe it will do the trick. I’m already planning to need a replacement alternator and starter. May as well be sure it’s reliable!

Points distributor is fine too.

My 421 never fails to start. :)

Im glad the clutch fan mod helped.

I used one of the Chinese HEIs for a while and it ran fine for what it was. Plus all the parts are easy to replace. Just carry and extra module/cap/rotor in your glovebox. I also might throw some extra heatsink grease under the module. Ive seen them skimp on that. And they often just fit poorly in cars designed for a small cap.

The Achilles heel of almost all of the affordable distributors, is they tend to let in way more advance under throttle than a reasonably efficient engine will want. If you go through old threads on here you can find multiple ways people will limit the advance allowed by the canister, ranging from adding a mig bead to using a short screw.

On mine way back when before I switched to a small cap, I used this list
https://www.crankshaftcoalition.com/...ance_Specs.pdf

And purchased a can that allowed less advance and was happy with it. (VC1703)

Heck maybe that will be my next video, limiting vacuum advance.

Did you determine what was causing the no start? Was something bad in the original HEI? You mentioned earlier that there was a bad 12v wire causing the no start... unless you confirmed something was wrong with the HEI, buying a new one may not fix the no start issue... Im sure it will work ok but a GM HEI is better quality than a china made one. Hope you get it figured out.

It unfortunately is the result of loosing 12 volts at the distributor due to a poor wire splice connection as well as the distributor intermittently failing itself. I didn’t narrow down if it’s a bad coil, module, or pick up coil however a complete distributor was less expensive than buying components for old distributor.

Ok, just curious if you confirmed the HEI itself or any parts in it were actually "bad" or causing the problems, I only saw the poor wire splice issue... without testing to confirm a problem part in the HEI, its hard to say it was related to the intermittent start problems.

Yes. After repairing the wiring, it lost fire again and wouldn’t start after running and getting up to operating temperature. I confirmed 12 volts at the distributor during this latest no start event - no ignition spark. So in my weak minded diagnosis, it has to be HEI distributor related. I’m replacing it as soon as the garage is over 45 degrees. My old bones don’t fair well in a chilled state.

Tuff to see ya replace the whole HEI for what might be a open pickup coil or even a easier to replace module or poor connections on either of those two.

Kind of what I was saying... replacing a new coil, pick up coil, or module etc is a lot cheaper than a new repro HEI... then you still have the good GM parts inside like weights etc vs whats in the repro.

But I suppose thats an easy way to verify the other HEI had a problem somewhere causing the no start issues.

FWIW, The 2 white and green wires on the pole pieces tend to denigrate over the years as the vacuum advance turns the plate. Only takes a minute to give a good tug on them to make sure they're not broken internally. This will give you an intermittent electrical problem that can be hard to pinpoint. Been there done that, no T shirt either.

Over the years I've found it easier to test HEIs with VOM (volt ohm meters) than to fire a parts cannon at them. The only part that can't be tested accurately is the module. Coil, pickup coil can be tested pretty easily, if you eliminate the easily tested components the module is the last part to the puzzle.

You Tube link to testing and diagnosis of Pontiac HEI: https://www.youtube.com/watch?v=0ze4TpyHURw

Also look for someone having changed an ignition coil before you, that removed the tin ground strap, and never replaced it.

Testing costs nothing, parts cannons get expensive.