First 4 banger, a 29 roadster having problems.

[Ratatat]

Well, I bought my first model a with the 4 cylinder motor. It was built to run in The Race of Gentlemen. Rebuilt motor, new wiring, interior, brakes etc. I received it last Thursday. Met the shipper at a more convient place and drove the car home. It started right up but on the way home it was missing and backfiring and emitting blue smoke. Couldn't really dial it in to smooth it out. Pulled the plugs and the front three were really oil soaked and the last had some carbon build up but not wet. The ad stated the motor had been gone through and by appearances it had but I really don't know to what extent. I emailed the seller but haven't received word back as of yet.
The motor has a downdraft intake with a 94 carb, Red's headers and still has the spark advance and throttle which still function, and has a choke conversion instead of the idle mixture.
Obviously the only thing I can think of is that oil is bypassing the rings. Now is there another reason that the oil could be bypassing the rings other that bad rings or the cylinders are oval instead of round. Is there something that could be creating too much pressure to be forcing the oil past the rings.
I really like the car and enjoyed the short drive that I was able to take in it.

[DougT]

Does it have an oil bath air cleaner?

[P.S.]

Blue smoke? Ouch.

I think the only way to get oil into an L-head motor's cylinders is either past the rings, past broken piston(s), or through the valve seats (like from the valve chamber through cracked or broken cast iron).

Is there any chance the car was inverted during its shipping? Curious to hear the seller's reply to you.

[George Miller]

First I would check the compression. The plugs might foul from a weak spark or wrong heat range of plug. He may have added oil to the gas, for sticking valves.
Just because some one went through the engine, is not always good. Any engine has to be built right, not that easy.

[Brendan]

spray can rebuild

[Ratatat]

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Originally Posted by Brendan

spray can rebuild

Ha!ha! No it wasn't a Krylon rebuild.

[Ratatat]

Originally Posted by DougT

Does it have an oil bath air cleaner?

No, aftermarket downdraft with filament air cleaner.

[Ratatat]

Originally Posted by P.S.

Blue smoke? Ouch.

I think the only way to get oil into an L-head motor's cylinders is either past the rings, past broken piston(s), or through the valve seats (like from the valve chamber through cracked or broken cast iron).

Is there any chance the car was inverted during its shipping? Curious to hear the seller's reply to you.

Here is the reply from the seller. The car was actually raced at Wildwood, NJ.

B.,
back firing is a timing, spark / carb issue/ adjustment. The car was an old restoration that was stored for many years when I bought it. everything had been set up for storage, the motor was filled with oil and the gas tank drained and dry, straight antifreeze etc. I boiled out the rad, drained, cleaned and changed the fluid in the rear, tranny. the brakes were all new when I checked them and repacked everything with grease, I first started the engine with all the old carb, etc, and found it had a slight head gasket leak. I pulled the head to also inspect the cylinders and pistons etc. when I had the head off, and got all the oil out of the cylinders everything looked great , all cylinders were very smooth, no ridges or score marks and the pistons were very tight in the cylinders ( no wiggle room) most of the engines I see have a lot of piston slop and still run great and these were nice and tight, it looked like the engine had been rebuilt not long before it was laid up. I had the head milled to make sure it was true and replaced two bad studs and a new head gasket, it starts right up and ides very smooth when its all dialed in, I noticed a bit of smoke when it first starts but the clears up, I haven't had any problems with it running and driving and it sits and idles great, unless something is hanging up in the carb? float? and your dumping a lot of gas , especially with the new down draft intake and carb you could be washing down the cylinders and fouling the plugs and creating smoke.
Like I said when I did an inspection and drained the old oil including filled cylinders, everything looked like new inside , except for milled the head true, new head gasket and replacing a few head studs, new intake and exhaust and carb, I didn't do any internal work to the engine and I drove it around town here a few times and then all weekend around town in Wildwood NJ as basically my only transportation as well as racing. it always fired right up and with a bit of adjustment idled perfectly. I would check and clean the plugs and or replace them and work on readjusting the carb as well as the timing advance, like I said backfiring in the carb is not an engine problem but a fuel/ignition/timing adjustment. hope this helps,

[JtownJoe]

Many years ago when I was in auto mechanic shop we were taught that the first step in any diagnostics or tune up was a compression test.

[P.S.]

My goodness.... The seller did an awful lot of work on it, and sold it to you pretty much untested, it sounds. Can you please share the text from the original ad? The way he worded the response here leaves a lot of wiggle room in his comments.

Blue smoke is an indication of burning oil, not gas. So, rule out the bad carb issue causing blue smoke. Unless the gas tank was filled with diesel fuel or some other oil based liquid by mistake, that would not cause blue smoke.

I'm sure the Model A engine gurus will chime in here eventually. This is a real head-scratcher. I'm sorry, I have no answers.

Originally Posted by Ratatat

Here is the reply from the seller. The car was actually raced at Wildwood, NJ.

B.,
back firing is a timing, spark / carb issue/ adjustment. The car was an old restoration that was stored for many years when I bought it. everything had been set up for storage, the motor was filled with oil and the gas tank drained and dry, straight antifreeze etc. I boiled out the rad, drained, cleaned and changed the fluid in the rear, tranny. the brakes were all new when I checked them and repacked everything with grease, I first started the engine with all the old carb, etc, and found it had a slight head gasket leak. I pulled the head to also inspect the cylinders and pistons etc. when I had the head off, and got all the oil out of the cylinders everything looked great , all cylinders were very smooth, no ridges or score marks and the pistons were very tight in the cylinders ( no wiggle room) most of the engines I see have a lot of piston slop and still run great and these were nice and tight, it looked like the engine had been rebuilt not long before it was laid up. I had the head milled to make sure it was true and replaced two bad studs and a new head gasket, it starts right up and ides very smooth when its all dialed in, I noticed a bit of smoke when it first starts but the clears up, I haven't had any problems with it running and driving and it sits and idles great, unless something is hanging up in the carb? float? and your dumping a lot of gas , especially with the new down draft intake and carb you could be washing down the cylinders and fouling the plugs and creating smoke.
Like I said when I did an inspection and drained the old oil including filled cylinders, everything looked like new inside , except for milled the head true, new head gasket and replacing a few head studs, new intake and exhaust and carb, I didn't do any internal work to the engine and I drove it around town here a few times and then all weekend around town in Wildwood NJ as basically my only transportation as well as racing. it always fired right up and with a bit of adjustment idled perfectly. I would check and clean the plugs and or replace them and work on readjusting the carb as well as the timing advance, like I said backfiring in the carb is not an engine problem but a fuel/ignition/timing adjustment. hope this helps,

[Mitch//pa]

he ran the engine then pulled the head, he then had to get all the oil out of the cylinders to inspect.... HMMMMMM

[700rpm]

Originally Posted by JtownJoe

Many years ago when I was in auto mechanic shop we were taught that the first step in any diagnostics or tune up was a compression test.

Yep. Do this first.

[Ratatat]

After having received the roadster and going through all this backfiring problems I was having with it I was looking at the plug wires and distributor cap and noticed that the plug wires on the cap were running in numerical order 1-2-3-4 and thought, that doesn't seem right. After a closer look at the distributor cap I read where it has the wire order embossed on the cap, 1-2-4-3. I switched the 3 & 4 plug wires and started it up. Now it's running fairly smooth but blowing twice as much blue smoke. Hahahaha
The car had been really backing firing like hell.
Went down to Vintage Ford here in Sacramento and picked up cap, rotor, plugs and points. Picked up a compression tester with adapters for the larger spark plugs and I'm going to run a compression check and see whats going on with all the smoke.
If the compression checks out OK and they are fairly even across the board where there is only a few lbs. difference, than what next?

[P.S.]

Ahha. So you are in or near Sacramento! Im sure that just about anyone in the Capitol A's will be delighted to help you.

If I were to render a guess, it would be that having the 3-4 plugs reversed may have caused a head gasket or ring failure. Please report the results of your compression test when able.

[George Miller]

Originally Posted by Ratatat

After having received the roadster and going through all this backfiring problems I was having with it I was looking at the plug wires and distributor cap and noticed that the plug wires on the cap were running in numerical order 1-2-3-4 and thought, that doesn't seem right. After a closer look at the distributor cap I read where it has the wire order embossed on the cap, 1-2-4-3. I switched the 3 & 4 plug wires and started it up. Now it's running fairly smooth but blowing twice as much blue smoke. Hahahaha
The car had been really backing firing like hell.
Went down to Vintage Ford here in Sacramento and picked up cap, rotor, plugs and points. Picked up a compression tester with adapters for the larger spark plugs and I'm going to run a compression check and see whats going on with all the smoke.
If the compression checks out OK and they are fairly even across the board where there is only a few lbs. difference, than what next?

So the same guy that rebuilt the engine wired the cap. Hum

[BILL WILLIAMSON]

I think I'd run really HIGH heat range plugs & drive it more, just in case the rings haven't SEATED in well yet.
Bill W.

[Patrick L.]

Originally Posted by Ratatat

After having received the roadster and going through all this backfiring problems I was having with it I was looking at the plug wires and distributor cap and noticed that the plug wires on the cap were running in numerical order 1-2-3-4 and thought, that doesn't seem right. After a closer look at the distributor cap I read where it has the wire order embossed on the cap, 1-2-4-3. I switched the 3 & 4 plug wires and started it up. Now it's running fairly smooth but blowing twice as much blue smoke. Hahahaha
The car had been really backing firing like hell.
Went down to Vintage Ford here in Sacramento and picked up cap, rotor, plugs and points. Picked up a compression tester with adapters for the larger spark plugs and I'm going to run a compression check and see whats going on with all the smoke.
If the compression checks out OK and they are fairly even across the board where there is only a few lbs. difference, than what next?

Once there are some compression readings to look at, then we can go from there.
Compression readings are not an indication of the health of the oil rings though.
But, we first need to see what you have to work with.

[Wilbur]

Can you post a picture of the car? I was at the race this fall and shot a bunch of video clips . I would be curious to see how bad she smoked during the race . He may have run the crap of it there and then dumped it onto you. The race was cool, but seemed hellish abusive on the old girls. Some of the non-local idiots actually ran their cars along the edge of the salt water, spraying that corrosive nectar all over the car. I wouldn't be anxious to own a car that was in that race... Unless you plan on racing and getting inside the engine on a regular basis. Blue smoke just means that oil is getting into the combustion chamber, simple as that. Either a broken ring or a beat valve guide. Step number one is a compression test. Good luck!

[Tomy Turbos]

I'm puzzled by the 'mis-wired' situation as I always thought it was pretty much impossible to do on this motor, provided that these are stock/original wires.

The wires are equal-length and the Cap's internal routing is such that even if it was not indexed to the Dizzy's base, 180 degrees would produce the same results. And yes, even though the Firing Order is 1243, the visual layout is 1234.

[Tom Wesenberg]

If the tops of the pistons have carbon, but it's clean around the outer diameter on the top, then that's a good indication of oil getting past the rings.

If you pull the manifold away from the block and see thick carbon built up in the intake ports, or especially under the heads of the intake valves, then that indicates the oil is getting past the valve guides.