Day goes from good to bad in one shift

[Dave in Denver]

Decided to drive my 1930 Tudor Seadn to work today. It is a nice 25 mile drive along two lane country roads. It bgan to rain this morning hafl way into the trip but all was good, the car was running smooth, no leaks and the traffic was light. It was a good day at work, no issues, spent some time staring out the window at the Model A etc. Got in the car for the drive home, even left a few minutes early so it would be an enjoyable drive. About half way home leaving a stop light, i shift from 1st to second at 10 mph, shift from 2nd to third at 30mph on my way to 45 mph. No sooner do I shift into 3rd and I feel a BOOM!!! (at least it felt like an explosion) from in front of me. I shift into neutral and coast to the side of the road. with my heart in my stomach. As I get out I look for a puddle of oil. (None to be found) open each side of the hood looking for a gapping hole in the block (none to be found). As I look around for evidence of what happened, I pull on the fan belt and it turns. Not only does it turn but I also see the crank pulley turning. I know from working on this car and my truck after (making sure I did not have spinach for lunch) I am not strong enough to turn over 4 banger by using the fan belt. Without opening the oil pan or pulling the head I am guessing I snapped the crankshaft.

Now I only hope that the block and pistons are still OK.

Has anyone else ever experience the sudden boom and the coast ot the road and gain the ability to rotate the crank from the fan belt?

Also if the crankshaft did split, is the engine rebuildable? or should I start from scratch.

Just before the engine cratered it was running so smooth.

The engine was a inserted, non-pressureized Model A Ford Engine with Riley Two Port (Serial #61) on top, fed by a weber 32/36 dgv and sparked by pertronix, backed up by a mitchell transmission and a mitchell over drive. It has been in service for approx 9 years and about 4000 miles.

I do have a very good partner in the hobby in my wife. After I called her she came to meet me with the truck and a tow strap and my Tudor was pulled all the way home.

Dave

[bogdonj]

doesn't sound good but could it of backfired really loud? I only say this because if you blew the engine I would expect more damage. Did you try and restart it? You said no visible damage?

[Bruce Lancaster]

There are still alternative explanations possible! Cam, cam drive, pulley...
Test crankshaft "continuity" first; car in gear, distributor cap off. Push car forward, see if rotor turns. See if ratchet bolt that holds pulley up front turns. Does it turn when you turn pulley by fanbelt?? Is it loose or tight in crank?
Pull plugs...look in holes, push car some more. Do pistons move, or some pistons, or none??
I'm too tired now, but still lots of possibilities and tests to do. And if crank snapped...I would guess rear flange due to stress risers from seal.bearing mods.
Broken crank is alarmist until you have checked a lot of things...

[kelley's restoration]

contact crazydaddo over on the hamb
he has delt with these issues alot
really sounds like a cool setup and i hope you tghe best with your issues
tk

[mass A man]

Sounds like a stripped timing gear. With a warm engine, in neutral, you CAN pull the belt and rotate crank pretty easy if there is no gearing to cam. I had this happen to me with a 1930 Buick engine once. What you heard may have been a really super back fire when gear let go. Best of luck, sorry this had to happen, I guess it could have been worse, even if engine does in fact suffer from a more serious break.

[Craig Lewis]

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I'd look to be sure the big front nut is turning with the pulley....it could be just a keyway issue.

or...is it one of those 2-piece pulleys with the interlocking lugs and maybe one half is broken?

[dumb person]

Double check that the engine turns over with the crank handle i guess. Sounds repairable so far

[J Franklin]

Watch the crank pulley while someone steps on the starter that should give some answers. Make sure the distributor is rotating also.

[reggiedog]

HI: Sounds like the timing belt to me. So more or less that's fixable if I were u I would take the timing cover off before u even try to start the car u could do more damage. If that is not it it's got to be a bearing it sounds like some thing not that bad if your good at fixing stuff like that stuff it shouldn't cost u that much to fix. But take the timing cover off before u even try to start the car u could do more damage then there all ready is. But good luck let me know how or what it was. Best of luck reggiedog

[George Miller]

Not likely the crank broke in the front. They always break at the back of number 4 rod for the A. The B breaks at the flywheel flange. I would check the front pully and see if the key is sheered, if not maybe timing gear.

[Jim Brierley]

I agree with George as to where they break. Most likely the pulley or keyway. Timing gears won't act like that, the crank and pistons control compression and you won't easily turn the engine over if it has compression. Having said that, the crank is 80 years old! The rest of the engine is likely OK.

[kelley's restoration]

arn't rileys hard on timing gears?
i know in the dirrections it said to use an metal/aluminum timing gear
tk

[darrylkmc]

Put your timing pin in and see if you can tell if the cam gear is moving (using the hand crank, two person job?), at the same time watch to see if the rotor is also turning at the same time. This should tell you a lot.
What does the engine feel like if you turn it over with the hand crank?
Pull the front pulley front and back and see if it is loose.

Darryl in Fairbanks

[Dave in Denver]

Thank you for all the advice so far. I will be doing some experiementing tonite after work following your suggestions. I am breathing a bit better so far after reading your posts. I will provide discovery info this evening.

Riley's seem to be hard on everything, but they are fun to play with. I have one in my 1931 Closed cab truck as well. But that engine is am inserted pressurized Model A Ford.

Dave

[Milton]

"2/18/11 Went down to EC and back. For the second time in a row the engine over heated. Turned fan and saw front pulley turn. Found that it had slipped the crank key because crank nut came loose."

A notation from my journal, hope you're as fortunate. I learned long ago to expect the worst and then be damn glad you were wrong.

[700rpm]

I think of the solutions offered, Milton has it best. Simply turning the engine over with the crank and holding the timing pin in and watching the rotor will tell you a lot. Let us know.

[Dave in Denver]

I took some time to work on some of the solutions to find more symptoms towards a solution. Here is what I found.

1) I loosened the alternator and took off the belt. The billet steel pulley is definitely loose. I an rotate it and see that it has moved forward a small but. The 15/16" nut seems tight, I tried to get ot it but will have to worka buit more on that because the movement of the pulley makes getting the extension from the socket into the socket very difficult.

2) I took the side cover off the cam timing gear and discovered that it is aluminum. (this is a good) The teeth are in good condition and I can not get it to move (rotate) by hand. I did not want to put a screwdriver on it and mess the teeth up.

3) Someone suggested I put the car in gear and push it forward to see if the rotor turns. I tried this with the car in second gear and pushed it forward about a foot but the rotro did not move.

A couple of questions:

a) will the keyway snapping on the crank pulley make a LOUD metal noise?
b) if the cam gears look good and will not turn by hand, I assume it is still engaged with the crank gears and the crank is OK.
c) right after the loud noiuse occured last night it sounded like metal banging against something. I assume this could have been the crank pulley bouncing up and down.

Thanks,

Dave

[Frank Miller]

When you pushed the car did you feel any resistance from the motor? If you did and the rotor did not turn you may have a crank that is broke behind the timing gear. Try pushing the car in 3rd gear by pushing on the right front wheel while you observe the cam gear.

[Milton]

With the belt removed can you turn the pulley? If so, how does it feel, meaning, any resistance, does it let you feel if the key is trying to engage? How much does the pulley move up and down or side to side? Will it come out?

[Dave in Denver]

The pulley rotates freely with the belt removed. It also moves up and down and side to side. I need to try and push it in and then try to remove the 15/15" bolt. The pulley is a billet steel variety.