7/16" stud upgrade

[rogerguzzi]

Hello All

                I am going to upgrade the the cylinder head studs on the Vitesse!

This is the jig I have made.

1st photo  3/8" bush to locate and lock in position

2nd photo  9.8mm drilling bush 

3rd photo  tapping bush top to fit shank and bottom counter board to take the 7/16" tap so can be tapped square

I have bought 1 taper tap and 2 plug taps(not happy with with 1st one)

[rogerguzzi]

B****er pressed wrong key!!!!!!!!!!!

Roger

[Nick Jones]

Very good 

[rogerguzzi]

Hello Nick

                   Not sure why Chris Witor supplies set screws for the manifold side and studs for others?

But then not anticipating taking the head off often so probably not a problem?

I have 2 unused copper head gaskets that came with the car plus 2 or 3 used ones!(I have checked and the 7/16" studs fit the holes?)

Roger

[Nick Jones]

Might be because he’s been unable to find a supplier for the short studs at a reasonable cost? The long ones are likely the same as Mk2......

As I recall Alan just used to anneal the head gasket and re-use. Don’t think he’d had any problems in spite of the hard use.

Bit surprised that the holes in the head are large enough already - is this on the modified head, standard head or both? Might still need opening out a bit to fit depending on how the placement and angle tolerances in the combined holes stack.....

[rogerguzzi]

Hello Nick

                   I mean the holes in the gasket.

I have been having a go at cleaning the ports up(not as drastic as the modified head which is now in Bonny Scotland along with lots of other bits)

Just getting the nerve up to drill the block I mean what could possibly go wrong?

Roger

[rogerguzzi]

I forgot to say I have decided to fit the other camshaft Alan have made with extra lift on inlet and exhaust !

If the one with extra lift on exhaust made 120bhp(with modified head) it may not be far behind with a well cleaned up head?

Any body want the old one? it is showing no wear and I have numbered all the followers and they are the type with oil hole etc

Roger

[Nick Jones]

Might be up for that Roger.....

[rogerguzzi]

Hello All

                The new camshaft is fitted and timed about 108/109 degrees full lift to allow new chain to bed in and slip back to 110 degs

1 block stud drilled and tapped only 13 to go!(it was a bit nerve racking) 

I had a few practice goes on some old cast iron to get the feel.

I sealed the whole top of the block with clear parcel tape and made an attachment for the vacuum cleaner so I can suck all the swarf out before the jig is removed.

Roger

ps Nick if you want the camshaft and followers you can have first call on them.

 

[Nick Jones]

Nice careful work being done there 

[rogerguzzi]

Hello All

                All Drilled out and Tapped 7/16" UNF (A bit nerve racking at times!)  

I did all the tapping at about 1/4 to 1/2 turn then back off I did not want to risk a tap breakage or thread rip off

1st photo shows how I clamped jig to do end holes.

With all the studs in a straight edge across them at top and all in line within a few thou so very pleased with my efforts!

If any body does this I would say make sure you buy good quality taps (I bought 2 NOS ones a taper and bottom and the seller thought they were HSS!)

But I had a practice on some cast iron I have and it seemed to me they were loosing there edge! (probably Carbon Steel) ok for cleaning threads

So I bought a NOS Goliath HSS one(bottom) and that one was still cutting well and not binding after doing all 14 holes(used others to start holes off)

Thinking about the cylinder head why are some of the valve caps one piece and the other half two piece?

On the cylinder head I sold they were all one piece so does it matter?

I am using the valve springs Chris Witor recommends.

Roger

[John I]

9 minutes ago, rogerguzzi said:

 

1st photo shows how I clamped jig to do end holes.

With all the studs in a straight edge across them at top and all in line within a few thou so very pleased with my efforts!

 

 

 

Hi Roger,

I was wondering how you were going to achieve the clamping for the end studs. Very nice job all round, I was going to give mine to the machine shop but now you've got me thinking.

cheers john

[rogerguzzi]

Hello John

                   I can send you the jig and sleeves if you feel confident?

You would just need 2 GOOD quality taps(Taper and Bottom) and a 9.8mm drill

I do not think I will be doing another

As for the front clamp any piece of steel would do

The whole operation is not difficult if you take your time and double check the lining up of the jig before starting to drill and tap!

And as I said go slow with the tapping(I even sucked the swarf out after each bit of the drilling and between tapping operations)

Roger

[Nick Jones]

3 hours ago, rogerguzzi said:

Thinking about the cylinder head why are some of the valve caps one piece and the other half two piece?

Two piece caps should be the exhaust valves?  That's standard.

[rogerguzzi]

50 minutes ago, Nick Jones said:

Two piece caps should be the exhaust valves?  That's standard.

Hello Nick

                  But Why?

Alans head had solid on all valves!

Roger

[GT6Steve]

Don't forget to put a small chamfer at the top of all your new stud holes to avoid pulling the top thread....

 

[Nick Jones]

22 hours ago, rogerguzzi said:

But Why?

Alans head had solid on all valves!

The explanation usually given is to allow the exhaust valves to rotate more easily reducing seat wear.   Maybe.......

They have a slight reputation for fragility (probably only when stronger springs are fitted) and tend to get swapped for one piece ones in performance applications.

[Nick Jones]

6 hours ago, GT6Steve said:

Don't forget to put a small chamfer at the top of all your new stud holes to avoid pulling the top thread....

Good advice.

[thebrookster]

2 hours ago, Nick Jones said:

The explanation usually given is to allow the exhaust valves to rotate more easily reducing seat wear.   Maybe.......

They have a slight reputation for fragility (probably only when stronger springs are fitted) and tend to get swapped for one piece ones in performance applications.

Is it worth planning on going back to two piece caps then, or stick with one piece as Alan did?? (Asketh the recipient of Alan's performance head!!).

Phil

[Nick Jones]

I’d stick with the single piece (alloy?) ones - unless going back to stock springs and cam - which I don’t suppose you are.....

That head will need valve additive. Not much chance of getting inserts in it.

[John I]

6 hours ago, Nick Jones said:

I’d stick with the single piece (alloy?) ones - unless going back to stock springs and cam 

At what point cam wise would you go from two piece to one, is it only race spec that needs such exotics?

[John I]

On 16 August 2020 at 8:31 PM, rogerguzzi said:

Hello John

                   I can send you the jig and sleeves if you feel confident?

Hi Roger

That's very kind, I'd be really greatful.

Can you let me know how much I can send you for your time, materials and postage of course.

Cheers John.

[rogerguzzi]

Hello All

               I have been out of the loop for a week as Tinterweb went down in the storm and 3 x1 hour+ phone calls later and a new router we are back in the digital world

I have chamfered the holes (may counter bore them as Triumph did!)

I think I will go to one piece valve caps as I am going to the 308778 cam with extra lift on both lobes with the red springs as per Chris Witor.

Roger

 

[rogerguzzi]

Hello All

               I have had another close look at the block today and find the stud holes still have a counter bore of 7/16"+ and when a new stud is screwed in the plain part goes into the block by about 1 to 1 1/2 threads (as Triumph machined it) 

Why they counter bored it  so large is anybody's guess unless they were starting to fit 7/16" studs and just did all blocks the same (it would make sense and cause no harm)

Roger