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| Strange rattle sound when idling | Rate Topic |
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| Posted: 11-30-2020 12:14 am |
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1st Post |
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Art DeKneef Member
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I working on putting a GT engine and transmission into a 1974 JH. Everything is hooked up correctly. I aligned the cams and timing marks to TDC. I saw and verified that the piston was at the top. Everything looked good and I felt I lined everything up correctly. Engine started with a little effort. I figured the engine would need to be tuned after I started it. However, I can hear what I describe as a rattling sound. It is relatively consistent but not constant, if that makes sense. While I hold the accelerator pedal down a little to get a steady speed, I can hear this sound. I hear it once or maybe twice, then nothing for a couple of seconds then I hear it again. So I turned the engine off. Here's another thing. While sitting in the car I had my hand on the gear shift and when I heard the rattle, I could feel it through the gear shift. Thinking it might be something related to the trans. I looked inside the trans through the inspection hole and everything looked properly installed. I'm not sure it's the valves because I would think it would be a constant rattle. So before I pull the trans in an effort to narrow it down, I thought of asking the group if any of you might have some thoughts. Thanks, Art
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| Posted: 11-30-2020 02:06 pm |
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2nd Post |
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Steve Duncan Member
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Does operating the clutch change the sound?
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| Posted: 11-30-2020 04:23 pm |
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3rd Post |
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Art DeKneef Member
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NO difference. The car is on jack stands at the moment. With the clutch depressed or not, the rattle is there.
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| Posted: 11-30-2020 07:42 pm |
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4th Post |
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Steve Duncan Member
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If clutch actuation didn't effect noise then trans problem seems unlikely. My rattle(s) after engine/trans R&R this Spring were 1.The sheet metal piece that covers the area of the bell housing opposite the oil pan. 2. A muffler clamp that was just a little too close to the trans mount. I would also suggest lowering car off jack stands to see if that changes it.
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| Posted: 12-01-2020 02:17 am |
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5th Post |
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Esprit2 Member
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Have you tried crawling under the car while the engine is running. "IF" it's transmission related, the rattle might be more pronounced and directional under the car. Just be careful of what you touch while under there. Stay away from the busy front of the engine and the hot exhaust. Regards, Tim Engel
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| Posted: 12-01-2020 04:22 pm |
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6th Post |
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Art DeKneef Member
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I got under the car again to check everything one more time and the only thing that was loose was the fuel return line that goes into the carbon cannister. Since I don't have a cannister I left it alone before. I'll tape it out of the way but the sound that I heard had a heavier sound to it then what I think would be made with the fuel line. @Tim - I thought of that when the grandkids were over but I wanted to check everything before I try starting it again. I plan to get it to idle without someone in the car and then I can get under and take a listen. Hopefully I'll get a better idea of where it's coming from.
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| Posted: 12-02-2020 12:40 am |
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7th Post |
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Tom Bradley Member
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Make sure the nut at the back of the shifter mechanism holding it to the insulator is tight (assuming your trans is a Getrag 5-speed, see fig). Mine had a tendency to come loose and cause rattling until I put some thread locker on it. While you are at it, also check the "Grub screw". This also needed thread locker to stay on. Attachment: 5-speed shifter.jpg (Downloaded 99 times)
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| Posted: 12-02-2020 07:04 am |
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8th Post |
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discogodfather Member 
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I had some problems with my transmisson mount and the rubber disc mount holding the shifter mechanism to the car body. Some ticking noises on hard turns and the shifter would pop out of gear pretty easily on harder turns, plus some weird vibrations in the shifter. The trans mount itself is just two pieces of metal with a rubber block sandwiched in between. It looked fine but after taking it out I could literally peel the entire mount in half with hardly any force at all. Rubber was mush. I also replaced the top engine shock and both motor mounts. Solved all the problems.
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| Posted: 12-03-2020 02:07 pm |
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9th Post |
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Jagwire64 Member
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I had a similar [rattle] noise. Turned out to be the dust cover for the bell housing. Missing some bolts securing it to the bell housing. Haven't found a bolt to properly fit yet. But a zip tie has sorted the noise and all is quiet.
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| Posted: 12-12-2020 12:49 am |
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10th Post |
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Art DeKneef Member
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I finally figured out where the rattle noise was coming from. While running the car and trying to narrow down where the noise was coming from I happened to noticed that the fan seemed to stutter when I heard the noise. So now looking closely at the fan I noticed it had a little wiggle room when looking closer. So I got the fan off, breaking one of the blades in the process. Started the car and no more noise. Thinking about this I thought how weird that something like this could be felt throughout the whole car. So it looks like I'll be getting an electric fan and installing that. Anyone have any suggestions on what works? I searched the forum and see a few mentioned. I looked at the Spal website and figure a 13" fan will work with the JH radiator. Need to decide on a pusher or puller.
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| Posted: 12-31-2020 07:40 am |
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11th Post |
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CDA951 Member
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If the fan was the source of the noise and you could also feel a vibration, the fan was likely damaged and you felt the resulting imbalance. As for an electric fan, it is a great upgrade. I went with the relatively cheap basic Hayden 12" fan kit from Moss Motors (it was on sale at the time and Moss HQ is the next town over from me so I could pick it up in person :). This kit uses the snap fasteners that go through the radiator fins, which is not my favorite solution but our Jensen-Healey was bought as a Lemons rally car so it sufficed for the time (and still does after over 20K miles in 2 years!). As for pusher or puller, it really depends on your individual setup and preference. I mounted the fan as a puller because there was room (fan blade could be reversed and run either way) and it allowed the oil cooler (also cobbled together from sale-priced Moss components) to be mounted in front of the radiator to take advantage of the fan while in traffic. I did splurge on a quality thermostatic probe for the radiator with an adjustable rheostat, and wired the relay coil input directly to the battery positive terminal to allow the fan to run after engine shutoff until the radiator cools down, as in a modern car. This setup allowed our J-H to stay cool during its 8,000-mile cross-country journey for one of the Lemons Rally events of 2019, most of which was in 90+ degree ambient temps with a lot of humidity. Earlier this year the fan stopped working, but this was due to a poor crimp in the Hayden wiring harness which was easily repaired. You might be better off with a slightly better-quality fan kit, and if I did it again I'd buy or make some proper mounting brackets.
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| Posted: 01-04-2021 01:45 am |
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12th Post |
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Art DeKneef Member
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Thanks for the info. I'm going to check a wrecking yard and see what I might find there so I can see a few different options before I decided what to get. I'm with you on using a good mounting kit to install it.
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