Engine stabiliser bar set up

[Bish]

Hello good people

My exhaust down pipe is literally laying on top of the subframe. It’s a stainless bigger bore pipe but I was hoping for a bit more clearance.
I have fitted the Volvo gearbox mount and intend to shim between the gearbox and mount to hopefully lift the rear of the engine and gearbox a bit. Hopefully giving a bit of clearance for the downpipe.
I also have new bushes for the engine stabiliser. Is there a procedure for it’s adjustment? Do you tighten the ball joint to engine bracket and then adjust the bar to give the engine a bit of lift? Or, is it just a case of fit the ball joint where it lands in the slot on the engine bracket and leave as is?

Cheers, Bish.

[Carledo]

TBH, I've never seen, even in their heyday, any concise instructions on how to adjust the engine stabiliser.

What I DO know, is that it's not sufficient to just bolt it up where it falls, ie where the other mounts naturally place it.

It seems to be needful to put a bit of extra tension on it, otherwise the O/S mount will soon drop the oil pump onto the rack. This seems to be pretty much the function of the stab bar, to compensate for an initial lousy design! It's almost Ford like (google pinto fires if your memory doesn't go back that far) in treating the symptoms rather than curing the cause.

But doing this will tend to pull your particular engine toward the n/s of the car, the exact opposite of what you need to get more downpipe clearance.

All I can say at this point is some of these "improved" downpipes are not as good a fit as one would hope for, the stainless one (Rimmers?) on our white auto Sprint runs perilously close to the transmission, so close in fact that I had to loosen the downpipe and drop it back to get access to the screw that holds the (plastic) inhibitor switch on! Which doesn't bode too well for the lifespan of the (rare and expensive) inhibit switch, though by a bit of diligent adjustment, I did get another half inch or so of clearance when I refitted the downpipe! Enough at least to get some heat wrap round it!

Steve

[cleverusername]

To be fair to Triumph, many of the problems owners are now encountering are less to do with the problem with the original design of the engine mounts and more to do with cars running with ancient engine mounts. Many of which are past their sell by date or been contaminated with oil.

Not helped by too many aftermarket parts supplies using the wrong grade rubber and being able to do something basic like stick rubber to metal.

[GrahamFountain]

Also to be fair, WRT the Sprint, the pressures to get 5000 built to homologate it for Group 1 on 1 Jan. 1974, in time for the BTCC changing to Group 1, may have shortened the time available for solving some design issues properly.

I know the FIA allowed homologation "on a promise to manufacture" (as the RAC's Neil Eason-Gibson described it to me once) in Group 4, as is known to have happened with the Chevette HS (which was approved in Nov. 1976 when the FIA inspection team were only satisfied all 400 were built late in 77) and seems more than likely with the TR8 (only about 150 FHC TR8s were built by the date of the approval on 1 April 1978, and another 250 or so were built at Canley some time after). But I've never heard of the FIA making such an accommodations for Group 1 production saloons.

It must have seemed like all BL's Xmases had come at once when the BTCC was announced as changing to Group 1 and Ford and Costain-Duckworth couldn't/wouldn't built the 5000 needed for Group 1 homologation of the RS1600 (not sure how many there were of those) or RS1800s (supposedly only 108 built - about 50 of which were really BDG 2 ltr engined Escort RSs for it's 1977 Group 4 variant approval).

The rest, as they say, is history.

And now, the 3rd coat of stripper may have dented the 1973 varnish on the Sprint's dash.

Graham

[GrahamFountain]

Found the FIA Papers on the Group 1 Doly Sprint and Group 4 Escort RS (you can just make out where something, perhaps "1800" was tipexed out from after "Escort RS" in the model name.

Graham

[xvivalve]

The stabiliser bar is in compression, not tension.

[Bish]

Thanks Gents.

I will adjust the bar for a little compression then. After I have had another look at the gear box mount.

The stainless downpipe is a Rimmers item, bought by the previous owner but never fitted. After all the trouble I had getting to the downpipe to manifold flange I can see why it was never fitted! I know these aftermarket parts aren’t the most perfect of designs but it does line up nicely with the gearbox bracket though, and now the whole system is stainless it looks and sounds lovely. I think it’s worth persevering with the gearbox mount to try and gain the clearance to subframe, but it may actually need a bit of heat and bending at my local exhaust shop if I can’t lift it a little.
My engine mounts are ‘good used’ that I have fitted recently, they are in a lot better condition than what I had on the car originally but I guess they are past their best too. Im not buying the crap repro mounts that are sold these days so I am thinking of investing in a pair of Chris Witors when they become available.

[Carledo]

The stabiliser bar is in compression, not tension.

That doesn't make any sense, torque reaction takes the engine the other way!

Steve

[xvivalve]

The stabiliser bar is in compression, not tension.

That doesn't make any sense, torque reaction takes the engine the other way!

Steve

If it is to counter torque reaction, why doesn't the 1850 wear one?

[Carledo]

The stabiliser bar is in compression, not tension.

That doesn't make any sense, torque reaction takes the engine the other way!

Steve

If it is to counter torque reaction, why doesn't the 1850 wear one?

1850 doesn't need one because it's engine mounts are at a sensible angle, the mount itself counters torque reaction! Not so on a Sprint with it's half assed horizontal O/S mount.

A subsidiary reason may be that a Sprint has MORE torque than an 1850.

But my money is on the mount theory. The Omega engine in the Dolomega has 147bhp and stump pulling torque, yet it does not have or need a stabiliser bar (either in OE form or in my Sprint) because the engine mounts are both at a sensible 40 degrees from vertical.

Steve

[xvivalve]

Nope, you only have to look at how the stabiliser mounts to the body to understand it. Were it in tension, it would have simply needed a ring connection beneath the bolt head, but it needs the robust bracket that in turn fixes beneath the bolt head because it is in compression and the bracket distributes these forces. The bracket is there due to the extra weight in a Sprint head being cantilevered over the nearside; it is actually a prop that stops the engine rotating clockwise when viewed from the front.

Torque reaction will counter or even neutralise the compression in the stabiliser, hence its name.

[Carledo]

Nope, you only have to look at how the stabiliser mounts to the body to understand it. Were it in tension, it would have simply needed a ring connection beneath the bolt head, but it needs the robust bracket that in turn fixes beneath the bolt head because it is in compression and the bracket distributes these forces. The bracket is there due to the extra weight in a Sprint head being cantilevered over the nearside; it is actually a prop that stops the engine rotating clockwise when viewed from the front.

Torque reaction will counter or even neutralise the compression in the stabiliser, hence its name.

I'm sorry but I find that unconvincing, IMO the bracketry would need to be beefy whichever way round the forces went. There is not THAT much extra weight in a Sprint head and even if there was, the correctly angled (and larger than an 1850s) N/S mount is perfectly capable of holding it up whilst static. Once running, torque reaction is pulling UP on the N/S mount and pushing DOWN on the O/S one, ie the crankshaft (rotating clockwise, as seen from the front) is trying to turn the block counterclockwise (according to Newton or somebody's 3rd law) thereby immediately and continuously putting the stab bar into tension (in varying degrees according to revs/torque generated) Whilst sound engineering practice would (again) prefer a stabiliser to BE in compression, there are obvious reasons, both practical and financial why the Sprint one isn't the "ideal" way round, it's shorter and cheaper like that!

About the only time the stab is under any compression would be engine braking on a trailing throttle, when NO torque is being generated by the engine and the drivetrain is trying to turn the block clockwise.

As has been discussed in another thread, I have raised the proposition that an improved O/S mount that is either vertical or angled upwards will negate the need for a stab bar altogether and Ian, who is apparently most advanced in his experiments, has tentatively agreed to try it! We shall see!

Steve

[xvivalve]

It’s the shape of the bracket that’s the give away, not the fact it’s ‘beefy’! You’re the one who constantly maligns BL for penny pinching and being s##t engineers, so why do you think they’d unnecessarily contrive that bracket when it could be superfluous?

The engine leans, and has additional weight as a cantilever; when the engine is static, the stabiliser is in compression. Torque will work against this when the engine is revved, but you can visibly see the block fall back when it is not.

You said “it seems needful to put a bit of extra tension on it” as part of the setting up. You cannot put tension onto it, you can only increase its compression by winding it out and effectively making it longer. Winding it in, and making it shorter will reduce the compression, but it will not in itself create tension.

[Carledo]

It’s the shape of the bracket that’s the give away, not the fact it’s ‘beefy’! You’re the one who constantly maligns BL for penny pinching and being s##t engineers, so why do you think they’d unnecessarily contrive that bracket when it could be superfluous?

The engine leans, and has additional weight as a cantilever; when the engine is static, the stabiliser is in compression. Torque will work against this when the engine is revved, but you can visibly see the block fall back when it is not.

You said “it seems needful to put a bit of extra tension on it” as part of the setting up. You cannot put tension onto it, you can only increase its compression by winding it out and effectively making it longer. Winding it in, and making it shorter will reduce the compression, but it will not in itself create tension.

I don't see that the shape of the brackets has a lot of bearing, the body side is easy to build strong, it's anchored firmly to the subframe mount bolt and transmits it's load directly into the strongest part of the chassis rail. Making the engine end equally strong just calls for more lateral thinking. I'm not saying the bracket and stab are superfluous, they obviously aren't or they wouldn't be there. But i suspect they are merely a cheaper solution than redesigning the subframe and O/S mount! I don't really blame the engineers, so much as their taskmasters, the accountants! BL's penny pinching WAS legendary, even you can't deny that! I love my BL cars, but that love hasn't blinded me to their little foibles!

Yes, the engine leans, but there is a "rest position" WITHOUT the stab fitted, which is, or should be, about right. Stable and level.

If you then fit the stab and adjust it to the "rest" position of the engine (as most do) then it's neutral, having no effect until force is applied to it one way or the other, tension under acceleration and compression under forced decelleration. If you rev the engine free it puts tension on as the revs climb and torque reaction increases, when you release the throttle, the torque vanishes so the engine drops back, but only to the "rest position" it needs a different external force applied such as that from the driveline under engine braking, to send it into compression.

But if you start from a neutral effect position and then shorten the stab, it WILL be in constant tension (except of course under engine braking when it might get back to neutral or a tad more) which takes the load off the weak O/S mount and reduces the amount of torque reaction VISIBLE when revving. The reaction is still there, it's just transferred into the much heavier body which moves considerably less (under the usual laws of physics) so it's not so noticeable. Watch any huge engined Yank V8 being revved and the whole body twists!

Now start from YOUR premise and adjust from neutral into compression (by lengthening the stab) all you are doing is putting a load on the stab bushes and INCREASING the load on the the O/S mount, forcing it down towards the rack. Now start the engine and the torque reaction will take it further as the first bit (taking the stab to neutral) is free! The survival time of the troublesome O/S mount is going to be drastically shortened thereby.

MOST engine stabilisers are designed to hold the engine in a precalculated neutral position so they do nothing till force is applied, then they limit the action in either case. A case in point being the original Mini, which has 2 axial engine/gearbox mounts which don't control TR at all, so the stab is vital and worn stab bushes make the engine try it's best to jump out of the car! The Sprint stab seems almost unique in needing that bit of tension to help it out. That's because it's not a necessity, (in the sense that the Mini one IS) it's the pragmatic solution to a designed in problem.

Steve

Edit, sorry, misread your opening statement and it was the strength of the body end you were on about. Doesn't change my opinion though, there is still a lot of force to control, extension or compression, the bracketry is no good if it bends under load! At the end of the day, the weakest link in the whole stab is the right angle 3/8" ball pin, i've seen more than a few of those worn halfway through!