Mysterious Clanking sound.. HELP!! [Archive] - Chevelle Tech

: Mysterious Clanking sound.. HELP!!


1Quik7D
Nov 7th, 99, 10:23 AM
I put a rebuilt SB in my 70 about 6 months ago. The motor has been running fine, but I have not driven the car. I had to rebuild the tranny, so I get it back in, and the motor is still running fine. last night I went to back the car out of the garage, and I hear this clanking sound. It initially sounded like a tool droping down and hitting stuff, but now there is a noticeable clank.

Here is the problem now: I can no longer get the motor to idle. I give it a little squirt of gas and it starts and then dies. If I continue to give it gas, it will stay running. (thats when I hear the clank.) Something else that is interesting is that the fuel line seems to be building pressure before it goes in the carb and the #7, #6, #8 header pipes are not hot like the others (at best they are warm). Any suggestions? Could I have a cam or valve problem? What is causing the clanking?

66 bowtie
Nov 7th, 99, 10:29 AM
umm could the clanking be piston slap? when the engine was rebuilt did u use new cam and lifters? is it backfiring at all? check the plugs in cyl # 6, 7, and 8. check if the plugs are foul that could cause the engine from firing in the 3 cyl.

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1Quik7D
Nov 7th, 99, 11:00 AM
I used a new cam and lifters. No backfiring. Is there any way to tell if the cam is damaged or if I have a problem with the valves? Thanks

I may have found the problem. I found a bent pushrod on the #6 cylinder. It was not even seated in the rocker when I found it. I can easily replace the pushrod, but is there anything else that I should be concerned about? What would cause this. Is the cam and lifter okay? Thanks again everyone.

[This message has been edited by 1Quik7D (edited 11-07-99).]

gUmBaLL68Malibu
Nov 7th, 99, 4:44 PM
Well i had a similar problem when i idled it sounded like a tool was banging around in the back of the engine and i found it out to be that the previous owners did not install the torque convertor and it was just hanging there *NOT GOOD* but it is fixed now. I did this by taking out the car to about 120mph to see how good it did @ high speeds but i didn't notice it while driving just during idle very odd.

Wally
Nov 7th, 99, 5:07 PM
gUmBaLL68Malibu, you have managed to confuse me no end. The torque was not installed? You drove the car to 120 mph? Now it's fixed?

Could it be the converter bolts were loose? Car won't go if converter not installed. Car will go if bolts loose, may make bad noise if bolts hits things.

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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette

gUmBaLL68Malibu
Nov 7th, 99, 8:50 PM
lemme reprash
i was testing the car and got up to 120mph and when i got home i heard the large clanking. i didn't do that when it ws loose
Yes it was a bolt that had came loose and almost completly around but i only heard it during idle

Philip
Nov 8th, 99, 12:55 AM
Check and see if the distributer cap is cracked. All of your symptoms point to this and lowering the engine to R&R tranny can break the cap. Besides dead cylinders the spark can jump around inside the cap and cause the wrong cylinder to fire and make loud clanking signs.

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Philip Valentine
Lakeside, AZ
Team Chevelle Member #42 GOLD
philip@chevelles.com

Cardiac
Nov 8th, 99, 1:09 AM
Rods???????

ED1966SS
Nov 8th, 99, 5:08 AM
If the engine will idle at all, or just use the starter, remove the valve covers and observe the valve train. This will show if the cam and all valve components are working.

Chevguy68
Nov 8th, 99, 10:16 AM
If you havent done it yet, try a valve adjustment. It never ceases to amaze me the amount of trouble poorly adjusted valves can cause. If it doesnt help, then at least you will already have your valve covers off to see what the valve train does when you try to start it.

--Jerry--

chev64
Nov 8th, 99, 3:05 PM
If you haven't done it yet, check the torque converter bolts.

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Leo Paugh
Maryland Chevelle Club #017
Those who do the world's real work don't usually wear ties.

Fred Ont canada
Nov 8th, 99, 7:49 PM
Piston to valve contact will cause bent push rods,and noise...FRED

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