69 mustang engine noise
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=576
Printed Date: December-02-2024 at 4:45pm
Topic: 69 mustang engine noise
Posted By: jeff howell
Subject: 69 mustang engine noise
Date Posted: June-30-2004 at 1:10am
I purchased a 69 mustang with a chrysler 273 V8. The owner is a friend of mine and had a complete rebuild on the engine before I bought it. After he had it rebuilt it made a knocking noise around the thermostat area when run hard and would quiet down when you backed off. It seemed to be related to cooling so we replaced the thermostat even though the indicator was reading ok (140). We thought if it were running to warm it might effect the clearances. Still made the noise. For fear of causing damage to the engine we have since had another machine shop tear it down and check clearances, rods, bearings, crank,ect. Nothing found. Re-assembled everything and the engine still makes the noise. It's not a piston slap sound but something erratic like tapping two rocks together. Doesn't make the noise when idling or running at lower RPM's. Has anyone experienced this sound before? My mechanic assures me it's not clearances or anything that will cause damage. We only have about 5 hours running time on the rebuild. Any suggestions would be appreciated.
-------------
jeff howell
|
Replies:
Posted By: David F
Date Posted: June-30-2004 at 12:42pm
|
I just notice my engine doing the same thing, but at idle. It does sound as if its coming from the thermostat area. I used a stethoscope to try and isolate the noise. Although my alternator was noisey, I could not hear the knocking sound on anything I probed, including the engine block. Keep looking and let me/us know what you find, I will do the same.
|
Posted By: Rick
Date Posted: June-30-2004 at 1:38pm
Do you have solid lifters? My 66 Sounded like a threshing machine and I was concerned until we adjusted the valves.
-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=250&yrstart=1996&yrend=2000%20" rel="nofollow - 2000 Ski
|
Posted By: David F
Date Posted: June-30-2004 at 4:48pm
|
No, it is not valve train noise (351W with hydraulic lifters). The noise is intermittant.
|
Posted By: jeff howell
Date Posted: June-30-2004 at 5:52pm
My noise is definitely around the thermostat area and just a bit to the left looking at the engine. I've listened on the intake area behind the carb. and you can't hear it. I move down on the valve heads and on top of the timing chain cover and you can't hear it. A friend of mine suggested lifter noise so at this point I'm still searching. Thanks for your suggestions.
-------------
jeff howell
|
Posted By: 66polyhead
Date Posted: June-30-2004 at 8:19pm
The cam thrust plate could be worn, did you check cam end play when you re-built? you should have 2-6 thousands clearance.
-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=220&yrstart=1925&yrend=1970" rel="nofollow - KY Wildcat
|
Posted By: jeff howell
Date Posted: June-30-2004 at 9:11pm
Hi 66 Wildcat- Thanks for responding. Forgive me but I'm not a mechanic so please bear with me. I think all areas were looked at because the 2nd overhaul was a different mech. and that noise was really why we tore it down again. But if it is a cam thrust plate clearance problem can it cause damage by running as usual? Would the noise from that area be on top of the intake around the thermostat?
-------------
jeff howell
|
Posted By: 66polyhead
Date Posted: June-30-2004 at 10:06pm
Does your thermo housing have a large brass, screw in over temp/pressure. spring housing in it?
The cam is directly under the intake, the thrust plate is behind the timing chain and gear cover, on the front of the block, just below the thermo housing (I'm assuming your thermo housing is in the front)
The thrust plate is flat and shaped like a football.
One hole in the center for the cam, and a bolt hole on either side.
The thrust plate is put on before the cam timing chain gear.
The cam has a thrust surface on the front bearing journal, the cam is slipped into the cam bearings in the block, and the thrust plate is bolted to the front of the block.
This keeps your timing gears and chain running parallel or true, and also keeps the cam from moving backwards and forwards, and the intake and exhaust lobes are directly under the appropiate lifters, or tappets. Many people don't think to check cam thrust; clearance is only 2 to 6 thousandths of an inch. Worn timing chain and gears, over a period of time, can wear down a thrust plate (which keeps the cam from moving back and forth)
If the thrust plate is worn, it is symetrical, so, all you have to do is flip it over to the other side. I am not questioning your mechanic's knowledge......just trying to help!
-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=220&yrstart=1925&yrend=1970" rel="nofollow - KY Wildcat
|
Posted By: jeff howell
Date Posted: July-01-2004 at 2:26am
Thanks for the explanation 66Wildcat. This gives me something to ask my mechanic about. If this is the noise I'm hearing do you think it's taking a chance on recking the engine if I continue to run? As far as the thermostat housing question- I'm not sure I understand. I'm not aware of a brass screw or spring housing.
-------------
jeff howell
|
Posted By: 66polyhead
Date Posted: July-01-2004 at 2:56am
Can't say without checking the engine myself. I'd hate to see you cause some terminal damage by beating it all week-end or something like that. If its been apart and back together twice and nothing can be found wrong... I'd say keep running it normal!, and see what happens. Maybe it will break-in, and the noise will go away. Good luck! hope you find a solution.
-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=220&yrstart=1925&yrend=1970" rel="nofollow - KY Wildcat
|
Posted By: David F
Date Posted: July-01-2004 at 3:10pm
|
My plan to isolate the noise to either the engine or accessories is to remove all belts and run the engine (be careful to NOT overheat the engine or exhaust hoses). Overheating the exhaust hoses is a real issue, so I may hook the garden hose to each exhasut manifold directly thereby allowing me to run the engine for a minute or so without the sea water pump, circulating pump or the alternate spinning. If the noise goes away, I will bring each accessory back on line one at a time. If the noise does not go away, then I will know it is in the engine and go from there. Incidently, my noise only occurs at idle, and I have a different engine from the original poster. However the sound is the same and from the same general area of the engine (right front/top).
|
Posted By: 64 Skier
Date Posted: July-13-2004 at 12:55am
I have the same noise. Exactly what you described...two rocks clicking together. It was my thermostat. I removed the thermostat and the noise went away.
Solid Lifters adjusted at .020 (double checked) and kinda noisey, but the noise your talking about was definitely not cam thrust or valves....like you said...two rocks clicking together.
Hope it's your thermostat!
-------------
64 Skier
66" HO VTX and 67" HO Triumph
http://www.correctcraftfan.com/diaries/details.asp?ID=1071&sort=&pagenum=3&yrstart=1971&yrend=1975 - 71CC
|
Posted By: jeff howell
Date Posted: July-19-2004 at 9:08pm
Thanks 64 Skier, I sure hope that's all mine is. I'll try that next time I go to the lake. Someone had a car thermostat in it when I first noticed it so I ordered an original one and it still makes the noise but I'll check it with it out. Did you put the thermostat back in?
-------------
jeff howell
|
Posted By: Lakeview
Date Posted: July-25-2004 at 3:56pm
If the noise went away with the stat removed,check the housing to make sure when it's tightened down it holds the rim of the stat in contact with the intake,the only other thought is to check if equipped with a circulating pump-the vanes in the housing-one might be broken and bouncing around inside the pump housing.
-------------
Lakeview
1992 Barefoot Nautique
1967 Barracuda SS
1967 Chris Craft Cavalier
|
|