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Old 11-13-2007, 03:00 AM   #1
mweav067
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'86 Oldsmobile Delta 88

The timing chain broke and has been replaced. The push rods got bent and have since been replaced.

Nothing wrong with the fuel lines or fuel pump.

Yet it won't start, it only spins. It sounds like it has compression.

Any ideas why it won't start?
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Old 11-13-2007, 04:21 AM   #2
67Coronet383
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Quote:
Originally Posted by mweav067
The timing chain broke and has been replaced. The push rods got bent and have since been replaced.

Nothing wrong with the fuel lines or fuel pump.

Yet it won't start, it only spins. It sounds like it has compression.

Any ideas why it won't start?
If the push rods are bent, you have bent valves as well.
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Old 11-13-2007, 11:31 PM   #3
adamc44
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does it have spark?
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Old 11-13-2007, 11:57 PM   #4
mweav067
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Strong spark from all plugs, and while the rods were bent I don't think the valves are bent because nothing happened to the springs or rockers.

Plus, if the valves were bent wouldn't there be some kind of popping or something to indicate it's trying to start?
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Old 11-14-2007, 06:04 AM   #5
67Coronet383
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Quote:
Originally Posted by mweav067
Strong spark from all plugs, and while the rods were bent I don't think the valves are bent because nothing happened to the springs or rockers.

Plus, if the valves were bent wouldn't there be some kind of popping or something to indicate it's trying to start?
The push rods bent because the valves had contact with the pistons. Push rods aren't the only thing that gets bent in that case most of the time. ;-)
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Old 11-14-2007, 02:20 PM   #6
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Not to interupt the conversation and "advice" with additional correct information, sometimes known as facts, but the engine in his car is 100% non-interference. No matter if it's a 3.0 or a 3.8 (a tiny bit of information that is always helpful), the valves WILL NOT contact the pistons unless you lose a valve keeper or the locks.

On these engines the valve springs go into coil bind about .100" before making contact with the piston. I can tell you from personal experience that a 3.8 with the heads shaved .060" still has plenty of room left between the valve and piston at TDC and coil bind. The same would hold true for the 3.0 as they're essentially the same. Unless the engine has been seriously modified, or put together with the wrong parts, the valve to piston contact theory is garbage.

On the other hand, every 3.0 or 3.8 I've seen with bent pushrods, and I've seen lots, has been caused by the engine being over revved. Fortunately they're a fairly stout engine and it normally causes no major damage. However, after an over rev and with bent pushrods I have seen them with collapsed (mechanically jammed) lifters, which could cause a no start.

All that being said, why are we wasting time with guessing? Has a compression check been accomplished yet, and if not, why not? Why hasn't it been recommended in this thread? Why do people keep yapping about things they don't know anything about?

The last question is rhetorical. Have a nice day.
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Old 11-14-2007, 05:17 PM   #7
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I assumed since his timing chain broke, and he had bent push rods - well, you know - the usual. I didn't stop to see if it was even an interference engine. It was obvious to me.

I guess no matter how obvious something may seem you still need to properly go about diagnosing.

Duh.



My bad.
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