Smoking engine

[Dwain G.]

This smoke or steam is coming from the tailpipe? Or is it coming from around the engine and radiator?
Original head gaskets were marked 'front top'. Was your new one marked? It is possible to install Commander head gaskets upside down and backwards. All holes line up fine this way except for a by-pass hole at the front. Watch for a smaller hole about 1" to the right of the front center head bolt hole.

[chlenz62]

Whoa! I was not aware of this small but significant detail! The machine shop is done with the head and when I receive the new head gasket from SI, I will definitely look for this alignment detail. The smoke was from the tail pipe and stopped after running the engine for about a half a minute. But large plumes of smoke. I'll update this posting once I have the head re-installed.

[chlenz62]

I checked the head gasket, it is not marked but it is different from end to end. I will definitely ensure I install it correctly. I just picked up the head from the machine shop. The head was "crowned" in the middle up to 5 mil. That's fairly significant and it appears I have found the source of the coolant leakage into the cylinders. I'll report out again once I receive the new head gasket from SI and install the head.

[Ross]

Do look carefully as I'm not sure if that was it. I say that because as as test I once supported a flat head on drill rod at its extremes and could easily deflect the center of the head .002" with my thumb. Hmm.

In my shop, where flatheads are more common than those excessively complicated ohv devices (a cylinder head with moving parts--who would want such a thing??) I have for years borrowed a tip from the boys who raced Hudsons back in the day. They coated their head gaskets with aluminum paint. I spray mine down on both sides with a heavy coat of the very highly pigmented Rustoleum Aluminum and slap the head on while its is still wet. This has the additional benefit of assisting any little irregularities on a gasket that has been in inventory for 60 years to flatten out nicely, kind of like dampening your best shirt before you iron it. Can't recall a single failure except for a run of Packard gaskets some years back where the center layer just might have been leftover oatmeal. I almost never mill flatheads unless there has been conversation between adjacent cylinders for quite some time.

[chlenz62]

Happy to report no smoke. It appears it might be best practice to check any head purchased from SI prior to install.

[Jeffry Cassel]

Glad your problem is resolved. Be sure to re-torque head after it has run for a bit.

[PackardV8]

The head was "crowned" in the middle up to 5 mil.

We might guess .005"? Which is very little, actually.

Do look carefully as I'm not sure if that was it. I say that because as as test I once supported a flat head on drill rod at its extremes and could easily deflect the center of the head .002" with my thumb. Hmm. . . I almost never mill flatheads unless there has been conversation between adjacent cylinders for quite some time.

For true, as Ross says, .005" may or may not have been the problem. But, yes, flatheads will deflect over their length. We do mill them all and one way to mill them successfully is to reference off the top side. Many flatheads were broached top and bottom surfaces at the same time, making the surfaces parallel. We hand scarf the top of the head with an 8" stone to remove any burrs and clamp it to the mill table; it pulls it down flat and thus gives a better shot at getting the bottom back parallel as well as flat.

Another FWIW, we mill all the block deck surfaces. They can be off more than one might imagine. A freshly milled block and head, with the head bolt holes tapped out and the bolts cleaned and torqued per the Shop Manual, has the best possible chance to hold the gasket.

Then, there was the Champion block and head some genius had cleaned with a belt sander and the surfaces went off in every possible direction; but that's another story.

jack vines

[Lynn]

Love it: "Then, there was the Champion block and head some genius had cleaned with a belt sander and the surfaces went off in every possible direction; but that's another story."

Got my laugh for the day.