I broke my V8. I've never heard of this, but I guess not working on American engines this may happen a lot. I was playing with my V8 and revved it up to about 7000rpms. the distributor actually came up about 1/8" and BENT the hold down. Thus causing a massive oil leak in the process. has anyone ever seen or heard of this?
The stupidist crap breaks at the worst time!
Dave

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1987 GT (my toy-see above), 1987 GT (daily driver), 1986 SE with a VW VR6, certified master technician/shop owner
www.njautobahn.com

A small block Chevy produces a lot of torque on the distributor shaft at very high RPM. If the hold down is even slightly loose, the ditributor tries to ride up on the cam gear and this can happen. (I once saw a distributor break a home made aluminum hold down and hit the underside of the hood on a 57 Chevy when the owner hit a very high rpm showing off to a friend) The oil leak is probably from the failed gasket under the distributor, just as the V6 o-ring problem leaks. Pull the distributor, check the gear on the bottom of the distributor drive. Does it now have a curve rather than the orginal straighter gear? I would change the gear to a bronze gear, and replace the gasket under the distributor flat. Possibly change the distributor if the shaft got tweaked, it can bend. Then take a light and look at the cam gear down the hole. If you see any mangled gears or chips you have to pull the cam and replace it, the gear is ground onto the camshaft. It isn't that bad removing a cam, I do it on 2 of my V8 Fieros fairly often to experiement with different cams.

If the gear on the cam looks good from the top view, install the distributor and fire it up, set timing and let it warm. Watch for oil leaks within the first few minutes since the oil is cold and the pressure will be higher. If you are running a roller cam 7000 rpm blasts are doable but I would limit the extremes if possible. I know your induction system wants to scream up to the moon and it must really fly but 7000 is a bit high for a street motor to live for a long time.

Generally this isn't the death of a motor, just a problem that has to be addressed and cautions taken. I have had motors hit 8200 rpm with no ill effects but that was on the track and I didn't expect 100,000 miles out of them. it was also a heavily modified motor with a rev kit and a rev limiter set at 8400.

Good luck, hope this helps some.

I pulled the distributor out and it looked fine. It is a Mallory unit, so the gear is already metal. No signs of tearing up the cam gear. Replaced the hold down with a bigger, stronger piece and it all looks to be good. Hopefully this won't happen again or I'll have to concider swapping in a 24v VR6
Thanks for the input
Dave

sounds to me liek the hold down was defective. they are cheap, and some are not so good. this will show up more if you have a high volume oil pump and/or a tweaked bypass spring.
that's the cause. the fix is reinstall it with the right hold down. the gears should be checked on the bottom edges for burrs if it got dis-engaged from the cam gear. the biggest issue wiht this failure is getting the oil pump shaft lined back up again.
7k on a 350 is a tad high. a 305/327 is not as bad. 350's and up need to be specifically built to handle any sustained rpm over 5k.
the blips for show off are ok, but even then you can cremate an engine if it is not properly built even with no load.
if done properly, compared to an sbc, that vr6 would look lame in comparison. as you well know being in the trade, it is all in how the motor is put together. no offense to the vr6 or the sbc meant, it is all in the build and the design points for the build.

The hold down I originally used was half the size and thickness of the one I have on it now. I was just clearing out the engine at 7000rpms (and seeing if my neighbors were awake yet). I don't normally run it there. I guess it was just a cheap part. The gears amazingly didn't show any signs of wearing from the problem. I think cleaning up all the oil was the hardest part.
Dave

quote Originally posted by tjm4fun: 7k on a 350 is a tad high. a 305/327 is not as bad. 350's and up need to be specifically built to handle any sustained rpm over 5k. the blips for show off are ok, but even then you can cremate an engine if it is not properly built even with no load.

Any 350 ever built will turn 6000... at least the bottom end. Most older ones will need valvesprings to do that.
A 305 has the same stroke as a 350.

Yeah - go ahead and put a VR6 in there. I say it can't be done!

I'll find a home for that SBC if you do...

It sounds like your dist. didn't go high enough to do damage. Glad you didn't try 8,000!

bmwguru if you could do a w12 swap like out of that GTI that would be awesome twin turbo tooo hmmm

I'm sure I could fab it up...the $$$$ would be the only drawback....a $40,000 drivetrain in a $2000 car....mmmm
Dave

quote Originally posted by bmwguru: I was playing with my V8 and revved it up to about 7000rpms...

Wow, SBC, 7,000 RPM, in the driveway, with no load? You're lucky that's all that happened...Is this a "race" built engine with modified internals & valve train? Valves are usually "floating" on a stock SBC long before you hit 7K. Hopefully, no other damage occured.

The engine is pretty built up. I spent all my money on the induction and valvetrain. I'm assuming the valves floated a little and the distributor wound up a little. I want to redo the heads again with something new, but I was hoping to get at least 1000 miles on these first.
Dave

quote Originally posted by bmwguru: The engine is pretty built up. I spent all my money on the induction and valvetrain. I'm assuming the valves floated a little and the distributor wound up a little. I want to redo the heads again with something new, but I was hoping to get at least 1000 miles on these first. Dave

Nice looking set-up! What is the multiple carb & manifold combination? It is impressive looking, to be sure. Let us know how you make out after replacing the distributor...you may have lucked out and have no further issues. Keep that sucker in the 5,500 to 6,000 range (tops) - on the street, most everything, even in a mildly built SBC, has been delivered by 5,500 RPM. Good luck.

It is a Chevy 350, bored 0.030" over. The induction system is four Weber 44IDF carburetors. The cam, heads, pistons are all not stock. I drove it on Friday and the engine feels as good as before. Ask anyone who has been in the car that the car will throw you into the seat violently. I took a customer out for a ride in it and he was very impressed...and he drove a M5.
Dave