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Rattletrap [ Scuttle Shake ]

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Re: Rattletrap

/ubbthreads/images/graemlins/savewave.gif Rick ,Your success in eliminating Scuttle Shake may very well be credited to elimination of the old moss gear box,I love em but they do leave a lot to be desired.In the case of the BJ8 cars a lot of the gear boxes are misaligned to the engine, this shakes the devil out of the car at about 55 MPH but can usually be minimised,driven through, at higher speeds.The misalignment usually occurs because; 1] the Dowel bolts are missing 2] The dowel bolts are installed at the wrong locations in the bell housing and 3] the dowel bolt holes have been Buggered by the PO.This misalignment allows the input shaft to wobble instead of following a more axial rotation path.-FWIW---Keoke /ubbthreads/images/graemlins/driving.gif
 
Re: Rattletrap

Hi Keoke,

I currently have the 4 rubber buffer pieces, but not the longer piece on the left side. It looks to me like the bonnet is not properly centered, there being almost no gap at the front end, which may be why the buffers aren't keeping the bonnet from rattling. As for the spring tension, it appears tight but I don't know how to make adjustments to make it tighter. I assume that the tighter the spring, the tighter it will hold down the bonnet and the less the bonnet can rattle, though I also assume that the gap has to be correct or I will still have metal against metal. And thanks. I have a feeling that I will be doing a lot of reading here. I just wish some of you guys spoke English. I have no idea what scuttle shake means.

Scott
 
Re: Rattletrap

Dave suggested Hendrix for brake drums and wheel balance. Forgot to mention that I had Hendrix do the same to my car this year. It makes for a better ride at 50 + MPH.
 
Re: Rattletrap

Thanks for lots of good info. Unless I am misunderstanding, "scuttle shake" means something that would happen at various speeds even on a smooth road. I have nothing like that...I have to go over bumps to experience anything worrying, and most bumps and RR crossings are nothing stressful...it's really "road under repair" situations that get me, and it sounds as though serious work would be required to find and fix the problem, and also as though I don't need to view it as urgent. My guess is, from reading the oracle Dave Russell, that the root cause is metal flex. Based on driving behaviour, I don't think I have a safety issue...something I can have done some winter when competing demands on the cash flow permit, rather than something that needs to be a priority?

Chris
 
Re: Rattletrap

I will at some point do all you suggest here John. I appreciate the time spent itemizing it too.

Good driving,
Chris
 
Re: Rattletrap

"Scuttle Shake" refers to speed related vibration that is felt in the steering wheel and dashboard/windshield area. This usually occurs between 50 to 65 mph speed range. It can be mild or severe ... and you know it if you have it /ubbthreads/images/graemlins/eek.gif. The generally accepted root cause is the weak structure of the frame bulkhead that goes around the transmission opening. The material around and above the "U" shape opening was not especially thick or reinforced from the factory. When the cars were road tested by the car magazines of the day some of the test drivers wrote about the scuttle shake. This was on nearly new cars so rusted structures was not a factor back then.

So you can have this "weak area" but some cars do not have scuttle shake because everything in the running gear is in a reasonably balanced state. As long as things are not out of balance the scuttle shake remains minor or non-existent. Once you have one or more items out of balance the vibrations will harmonically effect the whole car and be most noticable at the weakest area of the car. Once the bulkhead start to shake you can feel it through the dash, steering wheel mounting structure and windshield. Interestingly, if you put the top up or install a hardtop it reinforces the windshild area and seems to help eliminate or reduce the vibrations. Some have reinforced the trans opening by welding in right angle strips and/or welding an additional panel above the opening and report back that the scuttle shake is gone. This strengthens the weak area but does not fix the out-of-balance part(s) so you still might have extra wear on parts, fatique, handling problems, etc. occuring. The point that Dave makes (and I agree with) is you can have a very weak car because of rust that would be even more sensitive to anything being out-of-balance. The car may be so weak or out-of-alignment that conceivably, nothing you do would fix the scuttle shake. (at least that is my take on his comments that fits in with my opinions on scuttle shake)

BTW, I once had a '49 step van that had a horrible shake between 55 and 60 mph. Turned out to be worn U-joints on the drive shaft and I mention this because that too could be a cause on a Healey.

Chris, you asked for opinions on your "rattle trap" problem and if it is "serious" or could wait. I would at least check the front shock mounts to see if the bolts are tight and secure. This is relatively easy to get to from the engine compartment and wheel well area. If the shocks come off the wheel can flop and a serious accident could occur. It might be worth the trouble to find a knowledgable Healey person in your area or British car mechanic for a second opinion. Someone who could test drive the car and give an opinion on how severe your problem is. The Austin Healey clubs are a great resource for finding somebody in your area.

Cheers,
John
 
I also had the infamous shakes. I had the front end suspension rebuilt, including shocks. It did improve, but it was still there. I replaced my 2 remaining 48 spoke wheels with 60 spoke wheels. They were not new, but I was amazed how much smoother it got. Overtime I have learned I can control the shakes by having my beset wheels up front. I can now cruise 70-80 MPH with very little shaking.
Good luck,
Bill
BT7
 
Re: Rattletrap

Thanks, printed out your comments and suggestions for troubleshooting, and will take the car to my local mechanic before attempting any non-local driving.
C
 
Re: Rattletrap

Being aware of "scuttle shake" from the beginning upon restoring my BN7 I put extra welds and braces anywhere I thought would be needed. Also purchased new wheels/hubs tires etc. Must have worked because I have no scuttle shake, however, if going at high speed and rollover something large, like a stick, the dash gauges bounce. Kind of alarming, but no harm done.
 
To go back on topic I just eliminated some of my BT7 rattletrap noise by covering a few inches of the softtop frame with pipe insulation foam pad where it is close to the cockpit surround on both sides.

What was originally used to keep the metal to metal (alu) from contacting?
 
Re: Rattletrap Nightmare

Well, I've been in denial since reading some of your posts and Dave Russell's but the car cut out on me on Saturday. Found a wire had vibrated off the coil...there were a couple of loose ones, I didn't want to gamble, so I had it towed, and at the shop I asked them to check suspension and frame.

The worst has happened: turns out the car has been in an accident. Although most of the frame is solid, there has been a break and a poor (now broken) weld, just ahead of the front driver's side wheel.

Having the engine rebuilt and being able to drive the car regularly and at speed made the problem either appear or be noticed. Apart from preparing my book on how not to buy a Healey, I am considering my options.

I guess we could twist the frame into shape and weld. Or we could try to source and drop in a new frame, which apparently are available. As you can imagine, I am a little crestfallen right now, what with Mike Weir falling short at the Canadian Open and all.

Chris
 
Re: Rattletrap Nightmare

Chris,

I would get more opinions on fixing your frame. If you can find a qualified frame shop that can take measurements (they have some computerized frame machines that are extremely accurate), it's possible to bring the frame back to the original shape and weld up/reinforce the broken weld area. I guess it all depends on how sound the rest of the frame is and how extensive the damage is. Good luck.

Cheers,
John
 
Re: Rattletrap Nightmare

/ubbthreads/images/graemlins/savewave.gif

HI,Chris, since you are in CA why not let Jule take a look at the frame. I understnd they can do repair as well as replacement with new and have an excellent reputation in the Healey comunity .-Cheers---Keoke /ubbthreads/images/graemlins/smile.gif
 
Re: Rattletrap Nightmare

Found them. They are in Rockwood Ontario. Have no website, but a good reputation as they say. Here is a parts link that looks good I found at the same time. https://www.vintage-sportscar-touring.ca/technical/healeyspares.html

I am waiting for a local frame guy to look at the car today. Fingers crossed, as my fear, confirmed by the man who rebuild my engine and overdrive, is that if I go for a new frame, I will find it impossible not to fix tons and tons of things, since, while it's off, why not...
Apparently this could run me into $30K plus. Not a preferred outcome.
C.
 
Re: Rattletrap Nightmare

/ubbthreads/images/graemlins/savewave.gif Canuk, Jule Frame is in Canada Not Califonia!!-Cheers -Keoke
 
Re: Rattletrap Nightmare

HI John,Almost---Keoke /ubbthreads/images/graemlins/laugh.gif
 
Re: Rattletrap Nightmare

/ubbthreads/images/graemlins/savewave.gif
Thanks Reid , Do you know I could not find one of their advertisements in any of the current HLY Mags---Keoke
 
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