Position of dowell bolts on Healey bell housing

[bj7]

I am currently restoring a BJ7 Heaely which unfortunately I did not dis-assemble. Is there a specific position for the 2 dowell bolts ( aec3487) on the bell housing ? There is a total of 7 bolts on the housing. I have restored E types and Mark2 Jags. before but a Healey is new to me

 

[Robert560]

If you have the ability to measure the holes in the bellhousing and back plate through which the bolts pass, you'll notice that two measure a bit smaller than the others... they measure right around 0.375", if memory serves, while the others are like the next drill size up... like 13/32" or something.

Looking at the transmission from the REAR of the car, the two smaller holes for dowel bolts should be at the 11 o'clock position and then about 180 degrees from that at the 5 o'clock position. So on top, it's the hole opposite the one that threads into the engine block, and then 180 degrees from that one, under where the starter mounts.

FYI, for you or others, I ended up just using AN176 aircraft bolts in these holes, which are basically exactly what the original "dowel bolts" were (was missing one of my original dowel bolts). They cost me like $0.50 each.

Regards,
Robert

 

[Johnny]

Can't add much to what already was said, other than if you have the original bolts you'll notice they are a tighter fit in the dowel bolt positions than the other bolts.
good luck fitting the transmission back, read my post on installing the transmission back in the car. Definetly a two man job.

 

[bj7]

Many thanks for the advice. I will check bellhousing hole sizes. I think one of the dowelled bolts actually holds the earth strap ?

 

[GregW]

I think one of the dowelled bolts actually holds the earth strap ?

I believe the ground strap goes in the next hole up from the dowel pin. It was inline with the clutch slave on my BJ8, though it could have been put back wrong in the past (a new clutch had been installed). Putting it there makes more sense to me. 1) It reaches the frame mounting point, 2) It is less likely to get hit by things in/on the road.

 

[Robert560]

Don't know if it's correct or not, but my ground strap was indeed attached to the dowel bolt. I put it back the same way.

Regards,
Robert

 

[TimK]

I believe the circled hole is correct for the ground strap but the dowel bolt goes in the hole below that (at 5:00 o'clock). The other dowel bolt goes in the upper left hole (11:00 o'clock).

 

[Robert560]

Ooops... sorry about that error. You're right, that's not the dowel bolt hole... that's more like the 4 o'clock hole, not 5 o'clock. I never was much good at telling time.

 

[TimK]

hey, Robert. Good to have you on the forum and your picture is great. I checked out your website and profile and was interested in the aquisition of your Golden Beige BJ8. It looks really good.

 

[bj7]

Many thanks to all who responded. What a great resource! I am sure I will have many more questions before I am finished the car.

 

[Keoke]

Well lets look at the Ground stap'e location from an electrical standpoint, Here it is desirable to have the lowest resistance at the engine interface,Consequently. the strap would then connect to the lower starter attaching bolt.
This is in line with the preferred method defined in this thread.--Fwiw--Keoke

 

[Guy Marshall]

Hi guys - an old thread but a goodie.

One more question - which way should the bellhousing bolts point? The bottom couple have to be "nuts forward" but is that true of the others? Normally I'd like to see the nuts at the back.

I realise this is maybe unimportant, except for the dowel bolts which are proving very tight on my BN6... Any thoughts?

 

[Keoke]

Don't know if it's correct or not, but my ground strap was indeed attached to the dowel bolt. I put it back the same way.

Regards,
Robert

That is ok as electrically speaking either location is the same.

 

[steveg]

Hi guys - an old thread but a goodie.

One more question - which way should the bellhousing bolts point? The bottom couple have to be "nuts forward" but is that true of the others? Normally I'd like to see the nuts at the back.

I realise this is maybe unimportant, except for the dowel bolts which are proving very tight on my BN6... Any thoughts?

I found it easier with the nuts at the front because I could hang a combination wrench off them when I tightened the bolts from the rear. The Moss catalog factory drawings show all the bell-housing-to-rear-plate bolts pointing forward.

 

[Randy Forbes]

Hi guys - an old thread but a goodie.

One more question - which way should the bellhousing bolts point? The bottom couple have to be "nuts forward" but is that true of the others? Normally I'd like to see the nuts at the back.

I realise this is maybe unimportant, except for the dowel bolts which are proving very tight on my BN6... Any thoughts?

From a practical standpoint__which possibly flies in the face of a concours aplication__I try to have the nuts/exposed facing to the rear.

My line of thinking is that the exposed threads are less susceptible to being damaged by thrown up rocks and road debris, and may collect less grime and grit in them, making for an easier removal. Your experiences may differ.

I find that even my modern (well, significantly more modern than a Healey) sportscars have factory bolts with the threads-forward, even when they are easily reversed__which I do when serviced__so does anyone have empirical data, from an engineering standpoint, why they should face either direction?

 

[steveg]

....so does anyone have empirical data, from an engineering standpoint, why they should face either direction?

No data, but guessing on the factory assembly line, it must be slightly easier/quicker with bolts forward.

 

[roscoe]

I think that perhaps it stems from early aviation when folks were taught that when possible bolts should be installed with heads facing forward or heads facing inboard if rotating as in a helicopter rotor; the belief was/is that if a nut were to be left off or vibrated off ( not properly safetied etc.) the slipstream might keep the bolt in place or in the case of the rotating assembly, centrifugal force would do the same. While there may be a bit of truth to this it bears little on the bolts in question in this thread. Being a retired A& P mechanic I tend to follow the tradition unless there is a common sense reason not to, such as bleing able to remove the hardware more easily one way. Make sure things are properly torqued and use a thread locker on stuff you are not likley to want coming loose. And for all you concourse slaves (not being snarky here, just that that that aspect of Healey ownership has some clear limits for me) do what the judges expect to see.

 

[Keoke]

Doing what the judges expect to see----

 

[Editor_Reid]

"Concours," perhaps the most misunderstood and inappropriately maligned aspect of the car hobby. It's most typically denigrated by those who've never come close to one.

I don't know how anyone expects concours judges to see these bolts. We don't dismantle the cars, we don't slide mirrors under the car in search of dust particles on top of the exhaust pipes, and we don't have x-ray vision. Although it is kind of cool to be believed to possess superpowers - "Concours Man" sees ALL, deducts for EVERYTHING!

 

[steveg]

I think that perhaps it stems from early aviation when folks were taught that when possible bolts should be installed with heads facing forward or heads facing inboard if rotating as in a helicopter rotor; the belief was/is that if a nut were to be left off or vibrated off ( not properly safetied etc.) the slipstream might keep the bolt in place or in the case of the rotating assembly, centrifugal force would do the same. While there may be a bit of truth to this it bears little on the bolts in question in this thread. Being a retired A& P mechanic I tend to follow the tradition unless there is a common sense reason not to, such as bleing able to remove the hardware more easily one way. Make sure things are properly torqued and use a thread locker on stuff you are not likley to want coming loose. And for all you concourse slaves (not being snarky here, just that that that aspect of Healey ownership has some clear limits for me) do what the judges expect to see.

Quibble: aviation more likely to follow automotive practice than the other way around.
By this logic, the factory made a good choice by having the bell housing bolts point forward: since braking force is greater than acceleration, the bolt is more likely to stay in place if the nut falls off.