MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Noisy HTOB..should I worry
Posted by: limey222
Date: September 26, 2015 07:16PM

I've read a number of times of people having a noisy HTOB, sometimes it just goes away sometimes it stays but does't cause any problems. However with my luck anything is possible on this car. When I dove it around the block a few times I noticed that when I parked it on my driveway with the engine running there was a mechanical rattle that I had never heard before. It may be that it was always there except a large vacuum leak with I just rectified today had been causing my engine to idle at 1300rpm, now it idles at 650-700 rpm. When I put the clutch in the noise goes away. I know that we set the correct .100 clearance with shims when we installed the clutch and HTOB. However when we first tried to start the car after the install the clutch wouldn't release so we had to shock it free with it in gear and the wheels jacked off the floor. It freed up quite easily so I hope that no damage was done. Many people posted that it could have been the input shaft sticking in the pilot bearing that caused the original problem. Sin the clutch started working I have driven the car round the block trouble-shooting small problems and today is the first time that it has made this noise.
What do you guys think it may be?



Edited 1 time(s). Last edit at 09/26/2015 07:29PM by limey222.


RMO 699F
Mike Maloney
SW Ohio
(502 posts)

Registered:
12/09/2007 12:28PM

Main British Car:
MGB Sebring GT, Arkley Spriget, Lotus 7 Stalker 3.9 Rover, 1275cc, 3.4 V6

authors avatar
Re: Noisy HTOB..should I worry
Posted by: RMO 699F
Date: September 27, 2015 12:49AM

Michael...I have had the rattle with my htob going on eight years now..with the same result when I push the clutch in..I have driven the car from Ohio to Texas, Colorado, NC, Nebraska, Wisconsin. Etc. during these eight years with the rattle always there. I have been told by knowledgeable folks the rattle is typically the bearings in the overdrive...they apparently are very difficult to set up properly and even on "rebuilt" tyrannies can be noisy if not done properly. This is not to say you should be complacent about this, just be aware you are not the only one with this issue. I plan on having the fifth gear on my trans rebuilt properly this winter.



Edited 1 time(s). Last edit at 09/27/2015 10:36AM by RMO 699F.


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Noisy HTOB..should I worry
Posted by: limey222
Date: October 02, 2015 09:43AM

Now that my ignition problems have been fixed the idle is much smoother which has practically eliminated the "rattle"


Johnous
John Montgomery

(22 posts)

Registered:
01/11/2010 01:29PM

Main British Car:
1978 MGB Roadster 3.5L British Leyland V8

Re: Noisy HTOB..should I worry
Posted by: Johnous
Date: October 05, 2015 05:34PM

Michael,
When your HTOB was installed, were the bushings used a bit larger than the pilot shaft sleeve? Onj my T-5, I used oversized washer-like bushings and they have some slop around the pilot. Whenever the engine vibrates, these bearings rattle some. It may be worth taking off the cover and seeing if your HTOB bushings are the source of the rattle. That would explain the sound going away when you engage the clutch.


limey222
Michael Cubbon
Portland, OR
(129 posts)

Registered:
08/01/2015 12:55PM

Main British Car:
1969 MGB GM 3.4L V6

Re: Noisy HTOB..should I worry
Posted by: limey222
Date: October 06, 2015 09:23AM

It has quieten down a lot now that I have fixed the ignition problem that was causing a really rough idle.


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