valve springs [and setting clearances - edited]

[olr159w]

Hi

Per earlier thread my Sprint broke down for the first time and it turned out a valve spring had broken. Need new valve, collets, follower and spring. No other damage.

I'm in the process of lapping in the valves and got to thinking about the springs.

The springs in the car are TriumphTune uprated singles. Whether that was necessary or not I don't know. The car has a new billet fast road cam. But now I only have 15 of these obviously.

I still have the original regular springs in a box of parts and I was intending to put these back in. My rationale was 1) you need a complete set of matching springs 2) there is no point buying new springs a) anyway b) they might be worse quality than the originals.

I found reference somewhere - can't locate the tab at the moment - that springs should be replaced if either racing the car or if less than 40mm in length. The original springs vary between about 40.3 and 40.9 with most around 40.5. The TT uprate ones are generally all about 41mm.

My choices are :
- use originals > I can't see an issue except of course these are the most worn/shortest springs. All over 40mm though.
- use TT substituting best/longest original spring in place of broken one > the only question is whether having one non-uprated spring is really an issue. I can't see how it really could be. The question then is whether to use on exhaust or inlet and whether any particular location might be better
- buy new springs > feels like pointless expense and hassle esp if new stuff is uncertain quality

The car probably only does about 500 miles a year, I'd like to use it a little bit more but can't see it exceeding 1000. So fyi, low usage.

I'd be interested to know people's thoughts. I'm thinking of using the TT set and substituting one original spring and locating it on an exhaust valve most probably in one of the more central valves

Thanks

mark

[olr159w]

And another thing

I'll be checking and resetting the valve clearances. I have two issues with this:

1. Both workshop manual and Haynes talk about rotating the camshaft "by means of an open-ended spanner on the hexagon at the rear end of the camshaft". There is no such thing on my cam or the original cam that I still have (!)

2. In removing the head etc there should be no timing issues because it was all set before and refit is the reverse of removal. Obviously with the head off I would much prefer to set the valve clearances on the cylinder head on the workbench but the manual talks about doing it all assembled. It also talks about doing it assembled but needing - obviously - to remove the camshaft and rocker shaft to access and replace pallet shims. But that means undoing the head studs. How can that ever be a good idea for the head gasket?? I've never really understood this.

So bottom line is I would prefer to set all this on the workbench and if only the camshaft did have a hex on one end I could then turn it. But it doesn't

How do I best do this job please?

thks

[dursley92]

My fast road cam has the hexagon in the casting but I think its been re-profiled, its at the rear.

[olr159w]

As it turns out my original cam has that hex casting in the same place. The fast road one doesn't though.

I guess I'm going to have to make a lever arm that bolts onto the sprocket end instead. I can't see any merit in doing it with the head on the car and indeed it has always mystified and concerned me that in order to do this on the car one is required to loosen the head studs. That just seems like madness

Would welcome the views of others.

And I'm now thinking I will use the 15 remaining uprated springs and just substitute an original regular for one of the exhaust valves.

Likewise welcome opinions

thks

[GlenM]

As it turns out my original cam has that hex casting in the same place. The fast road one doesn't though.

I guess I'm going to have to make a lever arm that bolts onto the sprocket end instead. I can't see any merit in doing it with the head on the car and indeed it has always mystified and concerned me that in order to do this on the car one is required to loosen the head studs. That just seems like madness

Would welcome the views of others.

And I'm now thinking I will use the 15 remaining uprated springs and just substitute an original regular for one of the exhaust valves.

Likewise welcome opinions

thks

Personally, I wouldn't risk mixing the springs. Also, there was probably a good reason that TT recommended using uprated springs with that cam, so I would try sourcing a complete new set. It would be worth contacting one of the current cam manufacturing companies, as they could advise you and probably supply the correct springs. Piper, Kent and Newman are the ones that spring (no pun intended) to mind. One of those companies may well have made the TT cams anyway.

[olr159w]

I think the uprated springs were optional not mandated. Others here have advised they are not necessary

I've reverted to Plan D and am re-using the original springs. They are all in spec. with perhaps one that is a little more tired. The remaining 15 uprated ones turned out to be a mixed bag. Mostly they were fine but two outliers - one undersize and one a little longer.

Given one was undersized and arguably a bit knackered and another had broken causing the problems in the first place I decided to stick with the originals

[GlenM]

I think the uprated springs were optional not mandated. Others here have advised they are not necessary

I've reverted to Plan D and am re-using the original springs. They are all in spec. with perhaps one that is a little more tired. The remaining 15 uprated ones turned out to be a mixed bag. Mostly they were fine but two outliers - one undersize and one a little longer.

Given one was undersized and arguably a bit knackered and another had broken causing the problems in the first place I decided to stick with the originals

I suppose it all depends how much you are going to 'make use' of the fast road camshaft.

[olr159w]

On the limits maybe yes.

But the advice elsewhere was that the uprated springs with the fast road cam is not necessary and robs the car of a few BHP.

Finding uprated single springs to replace the existing ones seems to be impossible anyway. Its either standard or competition spec. No one seems to sell anything inbetween