Rattle

[Greybeard]

If we go along with SRM's reasoning, then anything which will cause excessive loading on the follower has to be investigated. Also worth a check that the rocker arms are not distorted.

Mr chaterlea25 very kindly sent me a set of used but good rocker arms last year as a possible solution to the valve adjusters going in too far problem. I'm happy that the problem is not bent rocker arms.

GB.. if you can hang on a few days, I will dig out a standard wide fin iron head and measure the valves. From memory the standard valves have a single wide groove and plain collets.

I have a feeling that I read here that there are two different types of plain collets for these engines.

The other SRM followers look OK, so I suspect the cam lobe on the baddie may hold the key, easy to measure and compare the lift on the lobes with the cam exposed.

I did measure the cam last year. I'll see if I can find my notes. None of the lobes was much different. Likewise the backs.

Otherwise it must be down to something amiss with the inlet valve, as outlined by RD. 

I'll be carefully checking when the engine is reassembled.

With the barrel off, a wipe round the cam trough and a gallon of some noxious hydrocarbon sloshed over the bottom end should do the job of a spring clean. As you say, the major particulates are safely in the filter.

That's reassuring.

Thanks for your suggestions; I appreciate the encouragement.

[chaterlea25]

Hi GB,
If shrapnel  from the follower has been sucked up by the return pump it will have damaged the pump
Before you panic cut open the filter and see if it has metal particles in it
Fish around in the oil tank with a magnet on a stick and see if there s anything in there too ?
Not all filters are equal

Test fit the valve, collar and collets and post some photos for us to see,

The grip of the taper collets should hold up the top cap's weight once assembled and pulled up into place
then check if the cap can rock , this is bad !! sometimes you can swop collets about and match up the pairs
check them with a magnifying glass and see if you can match up the machining marks
(once upon a time collets were supplied as a pair and only partially cut apart, leaving the fitter to part them and clean up any burrs but keeping them a a pair)

Look at the tops of the guides for contact marks

Just had another thought ???
As the top collars /collets ? were incorrect before I wonder if the iron head bikes use a different bottom collar ?
(no parts book to hand just now, too fkn cold to venture out at this hour)
The Alloy head bottom collars is quiet substantial, If these were fitted it could cause problem

A while ago I was sent a set of springs for a B33 (MCA)  one outer spring had an extra 1/2 - 2/3 turn of wire in it
but was the correct overall length
This was enough to make it coil bound on full lift, as I had 2446 Goldie scrambles cams fitted
Luckily I heard a pinging noise as I turned the engine ver on the bench
So check that each spring has the correct equal number of turns

I would fit a  light spring to the offending valve and test assemble the top end with only one pushrod etc
then check at full lift and see if the valve can be pushed down further before contacting cap to guide
If OK I would then fit one valve spring at a time on that valve and repeat the test

Enough for tonight
John

[Greybeard]

John,
Fantastic advice. Several things to try. I like the idea of simplifying the top-end so I can test just  that valves set-up.
Wifey is back from her travels so I don't expect to be in the shed much tomorrow. I will try to stay on it though.

[muskrat]

G'day GB.
All iron heads (and A7SS)have the same split cone (cotters) ans top collar and bottom cup. They differ from the A10 RR/SR alloy heads. Your cotters should be like a cone, smooth on the inside and out. The valve will have a wide groove square at the top and chambered at the bottom. The SR/RR valve stems just have a groove. The RR/SR cotters have a ridge on the inside to fit that groove. Do I remember correctly that you had the wrong cottars fitted?
Cheers

[JulianS]

The Rocket head takes a different bottom spring seat to the iron and Shooting Star head, to account for the larger  diameter of the outer spring. They will fit either way up, one way for standard springs and the other way up if you fit Gold Star springs (which need a different top collar)

Photo shows Rocket parts bottom seats right way up for standard Rocket springs.

[RDfella]

Greybeard – lots of good advice coming your way, but be methodical. Look at one thing at a time or you’ll never know what the exact problem was. As John says, try a quick top end assembly and check to see if the valves will open further at full lift. The idea of only using one spring is a good one. Only need a couple of head bolts, and easier to leave the pistons off – less hassle and chance of breaking a ring. Remember head gasket thickness affects tappet clearance. You may well have the wrong cotters fitted but, as I said before, they could be the cause of your problem or they may not be - whilst still being wrong. At present all you need to know is that your valve can open past full lift. If it doesn’t, that’s the time to check coil binding, springs, cotters, cups etc. otherwise you’ll end up going round in circles.
Good luck.

[Greybeard]

G'day GB.
All iron heads (and A7SS)have the same split cone (cotters) ans top collar and bottom cup. They differ from the A10 RR/SR alloy heads. Your cotters should be like a cone, smooth on the inside and out. The valve will have a wide groove square at the top and chambered at the bottom. The SR/RR valve stems just have a groove. The RR/SR cotters have a ridge on the inside to fit that groove. Do I remember correctly that you had the wrong cottars fitted?
Cheers

Yes, I used the old ridged jobbies when I had changed the valves for the 'wide groove square at the top and chambered at the bottom' type. Seemed to work ok but you chaps were mortified so I bought the correct cotters. Maybe my top collars are incorrect; the cotters do not sit quite as tight as I think they should. Do you know if the groovy cotters had a different top collar?

[Greybeard]

Greybeard – lots of good advice coming your way, but be methodical. Look at one thing at a time or you’ll never know what the exact problem was. As John says, try a quick top end assembly and check to see if the valves will open further at full lift. The idea of only using one spring is a good one. Only need a couple of head bolts, and easier to leave the pistons off – less hassle and chance of breaking a ring. Remember head gasket thickness affects tappet clearance. You may well have the wrong cotters fitted but, as I said before, they could be the cause of your problem or they may not be - whilst still being wrong. At present all you need to know is that your valve can open past full lift. If it doesn’t, that’s the time to check coil binding, springs, cotters, cups etc. otherwise you’ll end up going round in circles.
Good luck.

All good advice. I hadn't thought of trying the top-end without refitting the pistons. 

[Greybeard]

The Rocket head takes a different bottom spring seat to the iron and Shooting Star head, to account for the larger  diameter of the outer spring. They will fit either way up, one way for standard springs and the other way up if you fit Gold Star springs (which need a different top collar)

Photo shows Rocket parts bottom seats right way up for standard Rocket springs.

I'm sure that the valve seats and top collars are standard. I did put new springs on. I did use a 356 camshaft.

[worntorn]

Re the coil bound potential with the cam change-
From my reading the 356 cam is only marginally higher in lift than the 334. The big jump in lift is between the 356 and 357 with the 356 at 3.03" cam lift on intake vs 357 at 3.49" cam lift on intake.
I have not found the actual number for the 334, just the comment that they are similar in lift to the 356. In a photo alongside a 334 , the 356 appears much fatter in profile so it will have more overlap and be a bit racier than the 334 and maybe lose a bit of stump pulling ability.

On edit- lift graphs for all 3 cam types are on the Atlantic Green site.
With a bit of interpolation and +- it looks like
334- .28"
356- .305"
357-.345"

This lift at cam, intake.
Official number for the stock 357 and 356 from Megacycle is .349" and .303"
So the 356 is a small jump in lift from 334, 357 is a big jump from 356.

Glen

[berger]

hello Mr greybeard I can't remember but if you mentioned putting collets on the valves with a protruding bit on the inside of the collets and they are about 11mm long they are for super rocket valves that have a groove in the valve stem for the raised bit on the collets to sit in to. if that is the case the whole set up will compress the springs more because they hold the valve spring top keeper further down the valve stem and are very awkward to fit in the spring keeper and on the valve even without the springs on. once fitted without the springs the keepers rock about but would be able to hold everything together once in situ with springs etc. the thing is the spring keeper ends up at least 10mm from the top of the valve stem. with the correct collets fitted [about 7mm long] the spring keeper is 4mm down from the top of the valve [ measured from the top highest part of keeper to top of stem] , and that makes sense to me, maybe nonsense to others . so if the long collets with grooves were fitted I think coil bind could be possible but if this was the case why wasn't the other inlet follower destroyed

[berger]

worntorn I don't know all the maths geometry etc but I  just measured a 356 on all 4 lobes bottom to top and a 357 , the 357 is roughly with Vernier not mic - 20 thou bigger than 356 , haven't got a 334

[Swarfcut]

GB, As promised, dug a couple of Iron Heads from the pile and did some measuring. These are selected at random and are used parts and unchecked. They have not been dismantled or cleaned, so at best are just typical samples. Dimensions were identical, apart from as noted.

 Wide Fin, Cast Maker Mark IMC, Casting No. 67 1066. Iron Head.  Measurement of inlet valves only.

 All valve collets are flush with or very slightly below the flat inner area of the top valve spring cap.

 Distance from valve tip to the top edge of the collet is 8mm.  Inlet valve part 67 0323  1950 to '57.

 Inlet fitted valve spring length measured from top of valve cap rim to base of spring seat washer  41mm on one, 42mm on the other.

 Valve cap rim to head top face, at the inlet side, is 20 or 21mm, this depends on the different depths of the valve seat, assuming both heads have the same valves.

 The valve stem cutaway for the collets is cut 8mm from the valve tip, with a sharp cut at the top, then runs plain for 8mm, and then a 1.5mm  taper outwards at the bottom. The stem diameter at the cutaway is 6.5mm.   Collets are plain, no ridge and 7mm deep. Valve measures 100mm, tip to head.

 Sorry it is all metric, measured with a vernier caliper.

 See how your inlet valve set up compares. Later engines have inlet valve 67 0742, but I have no information about these and the difference from the earlier valve 67 0323 which you should have as standard, if you have the original head.

 Swarfy.

[Greybeard]

Swarfy, you absolute legend! I will check all of that info against my cylinder head. Thank you. Karma given.

[Greybeard]

I had a chance to work on my engine this morning. I'm planning on assembling the top without refitting the pistons just to check the valve movement.
I found that the bottom valve spring collar on the affected valve was upside down! Obviously this is not good, but it looks like it raises the spring by only about 20thou. Thoughts?