Popping Smoke

Lawndart · Jul 6, 2018

Yesterday I had to pick up my niece in the KS 95 deg heat. All well as usual until I got off the highway and sitting at a stop light. "What is that smell?" I look bad to see white-ish smoke.

Background -
Stock'ish engine with headers and 4bbl
Idle vacuum - 18-19
Dual exhaust with no x-over
Smoke from driver's side

https://flic.kr/p/LKy1z1

Crap. I get a block kit - however no indication.

Remove plugs for compression test - # 8 has a story to tell.

Compression on left bank are all 125ish minus #8 which proudly displays - 60psi. Double check confirms.

Valve cover off and engine turned over - no apparent issues.

Daily driver with over 40k miles in the last 3+ years, no abuse.
Thoughts?

bronconut73 · Jul 6, 2018

Stuck valve?

.....but you say you saw it working while you had the valve cover off.

Lawndart · Jul 6, 2018

Yep, all looks normal during a crank over with the valve cover removed.

I dribbled some oil in #8 and retested - 70-75-ish. So the "leak" seems to come from the top end or gasket. I fingered the springs with a screw driver and nothing was apparent.

I would do a leak-down test, but I'll have to report for... home duty.
Leak-down tomorrow, but at this point I imagine the head will have to be liberated.

bronconut73 · Jul 6, 2018

Well damn,.,,.....

jagbucket · Jul 8, 2018

check the head bolts might get away with just a resetting to spec. worth a try before a tear down . I had a 260 intake and exhaust off when i got to the head bolts found the weak cylinder's bolts had backed out. but the gasket looked intack like i just needed to troque it down. for peace of mind im glad i changed the gaskets but have always wondered
if i had to.

blubuckaroo · Jul 8, 2018

The deposits on the plug look like the result of coolant rather than oil.

Broncobowsher · Jul 8, 2018

Broken valve guide?

pcf_mark · Jul 8, 2018

That is a bummer. That plug looks wet with water is that correct? What are the ways water can get not a cylinder?

1) Crack in head in the chamber
2) Blown head gaskets / not enough clamp on the gasket
3) Crack cylinder
4) Could an intake gasket water seal leak and get sucked into the intake port? Classic Fel Pro failure but could it leach into the cylinder?
5) Cracked into leaking water into the intake runner

A leak down will be informative but I think just pressuring the cylinder will tell you a whole lot because it will leak out somewhere and give you an indicator. Hopefully the intake gasket just gave up.

https://www.youtube.com/watch?v=jGNwq1sHYXs this guy is a little twitchy with the camera but you can see how close the coolant passage is to the runner maybe you get lucky!

Lawndart · Jul 8, 2018

Performed leak-down yesterday and again today for conformation. Listening with a sonic detector, leak seemed to come from the block, not from the intake nor the exhaust.
Intake and head off.
The head break was as clean and I could do, but it took some effort as I am not a large person and certainly not as spry nor as strong as I used to be.
This is what I see - nothing definitive from my eyes.

(top of photo is bottom of head on engine)

pcf_mark · Jul 8, 2018

How did the intake gaskets look? The head gasket? It may be helpful to see them. I do not like the look of the right side of the bottom pic. Deck surface looks wet but it could be from you taking it apart.

Broncobowsher · Jul 8, 2018

The piston looks very wet, but is that from doing the wet ring test?
Broken ring? Still getting some compression off the second ring but not as much as with both good rings.

Rustytruck · Jul 9, 2018

That head gasket has been leaking for quite a while. Time to pull the head and replace both gaskets.

bmc69 · Jul 9, 2018

Rustytruck said:
That head gasket has been leaking for quite a while. Time to pull the head and replace both gaskets.

That ^. Make sure to check head and deck for flatness too.

Lawndart · Jul 9, 2018

pcf_mark said:
How did the intake gaskets look? The head gasket? It may be helpful to see them. I do not like the look of the right side of the bottom pic. Deck surface looks wet but it could be from you taking it apart.

Deck may be wet from the disassembly. The head puked a bit of coolant when divorced from the block. The intake gasket looks OK. I put an aluminum intake on the engine about 3.5 years ago.

Broncobowsher said:
The piston looks very wet, but is that from doing the wet ring test?
Broken ring? Still getting some compression off the second ring but not as much as with both good rings.

It might be a little wet from the oil test. Any way to test for the broken ring? If I have to pull the pan and remove the piston, I may just yank the engine and rebuild it.

Rustytruck said:
That head gasket has been leaking for quite a while. Time to pull the head and replace both gaskets.

Are you seeing evidence of the gasket leaking? Could this have been the cause of the smoke and compression loss?

The grand Q would be - Would you just clean it up, and put it back together?

tirewater · Jul 9, 2018

Doesn't appear to be a coolant issue. Typically the piston and head would have a scoured look if there was water getting into the cylinder.

From your leak down test, it sounds like a broken ring.

Rustytruck · Jul 9, 2018

When you look at the head and block you should see a clean ring around the head and the block where the fire ring on the head gasket is stuck to the head and the deck of the block. It leaves a pretty visible clean ring. Any darkness or or rust going across that ring is a leak in the gasket. If you look at the picture below you will see clean rings around the gasket bores except where the dark corrosion goes across the fire ring in the lower right hand corner. That dark area is a leak that crosses over into the cylinder. Once you get the surface of the head and block clean check to make sure they are flat also I recommend you put the head on the block and screw down the bolts and make sure they will clamp down on the head without the gasket there and make sure the head dowels are not keeping the head off the block. That way when you actually put the head on you know that when there is a gasket in there the bolts will actually clamp the head down on the gasket properly. Unfortunately when Ford made our engines back in the 70's they used low tech steel in their head gaskets are through time they leak enough coolant and the fire rings rust out and the gaskets fail.

http://www.saabnet.com/tsn/bb/NG900/index.html?bID=242395

pcf_mark · Jul 9, 2018

i think the operative question now is - is that water in the cylinder and did it get there from failure or disassembly? With low compression it could be a ring but with a wet cylinder I'm guessing head gasket.

Rustytruck · Jul 9, 2018

As far as Would I clean it up and go from there? the answer is yes I would. The only other option is rebuilding the whole thing. So for $150 and run it or 1500 to rebuild it. $150 may buy you time to rebuild an other engine if needed. The only way to tell is put it back together and see if it solved the problem or not. If not a whole battery of functional testing including compression, leak down and timing chain testing and crankshaft end play will tell you conditioning. Its an old motor and will sooner or later need reconditioning but the real question is does it need it today or wait until funds or time are better later? Personally I would like to keep it running as long as I can and build a motor on my timing than have the Bronco down for a month running down the rabbit hole.

Lawndart · Jul 9, 2018

Thanks Rusty and everyone!
Here are a couple more pics. This is the block side of the gasket; fire ring certainly looks suspect.

Parts on order.
Here is my plan.
- leak test the head
- leak test #7 & #8 (fuel in cylinder with pistons at roughly the same height. Watch and compare leak-down times as a test for broke ring(s) in #8.
- If all goes OK, clean and reassemble the head and compression test #8. If the compression is back in line with the others, replace the other head gasket.

Monitor and rebuild this winter, or next; summer aint no time for a Bronco to be down!

pcf_mark · Jul 9, 2018

That head gasket sure looks iffy. Hopefully you found your problem.

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