Hi
I am currently having a conversation with a reputable valve manufacturer. For me to have a pair of valves made is an extremely expensive game. If I get a batch of 20 made they'll come out at just over £32 each.
Anybody interest please let me know and I'll take it from there. I obviously need to sell 18 valves to make it a sound proposition.
Mike 8) 8) 8)
Hi Mike,
I could be interested, depending on what material is used to make the valves. Do you have that info ? A recent valve discussion on the AOMCC forum produced the recommendation that the valves should be "plasma nitride coated" if working in cast iron guides (am I correct in presuming out Sloper guides are cast iron ?).
Cheers,
Bevan
what are the exact dims on these valves , i may have some already
:) :) :)
Hi Craig.
My Info is thus: -
Head Diameter. 1.75"
Length----3+15/16"(3.9375")
Stem Diameter 3/8" (.375")
I have no idea about the collett groove
If in fact you do have such then I shall be very interested--cos the Co has a 12/14 week lead time
As for the material---no idea but I would suggest that the relevant Coy would "know what they are doing".
Mike 8) 8) 8)
:) :) :)
Sorry guys, not enuf interest so I shall not order a batch. Regrets to those who had hoped for some.
Mike 8) 8) 8) 8)
Mike,
1948-84 Harley Panhead/ Shovelhead valves may be an alternative. All the dimensions appear to be identical to those of the Sloper and the collet groove appears compatible.
I've ordered some from a UK supplier and some Nitrided ones from the US. They're really cheap £11.35 for a pair and seem to be a stock item.
I'll send a post when I receive them to let people know whether they look OK.
I've also order some cast iron valve guides - I'm having trouble with air leaking past mine.
:) :)
Hi
Thanks for that, Craig kindly sent me one to try, sadly the are just over a 1/10th" too short. I think that they could be made to fit but I don't really wish to go down that line. Unfortunately the collet grove is also 1/10th too far down the stem. But as you say the other dimensions are spot on.
Thanks agen for your input.
Mike
use valve caps
I'm not sure that its a case of 'making them fit'. It should be possible to take up the extra 1/10 with the tappet adjuster ( I'm using A10 ones because the originals on my Sloper were worn out) and the lower groove just means that the springs will be slightly more compressed. The fact that they're nitrided should benefit the unlubricated valve guides.
:) :) :)
Ok guys this is a new train of thought.
What valve caps would you suggest because its something that I have never done before and so have no idea.
Just to confirm---are you using A10 valves in a Sloper.
Your assist very much appreciated.
Mike 8) 8) 8) 8)
No I'm not using A10 valves just the tappet adjusters. I've used these to replace the adjusters which engage with the push rods. My original items were totally shot. The A10 adjusters are relatively long and so should be able to take up the extra 0.1 inch.
I've never used valve caps either, but I'm not sure whether they're necessary. I'm also not too sure where to source some that will fit. The only ones I've seen are for the Honda GX and I imagine that these will be too small. However because they don't need to be mega hard unlike the valves themselves then it should be possible to make some.
If valve caps aren't used then the main problem that I can see concerns the valve lifter. The rocker arm on the side where the Valve lifter engages will be slightly higher. However I think that this will still be OK.
I don't know for certain whether these will be suitable because mine haven't been delivered yet. However a slightly shorter length doesn't seem like too much of a problem. I'll certainly be giving these valves a go because I don't have much choice. The stems on my valves are badly worn and air is leaking past the inlet guide. When I found these valves on Ebay I couldn't believe how close a match they were - I also couldn't believe the price. The valves that Cornucopia advertise as 'machinable alternatives' are totally unsuitable.
you can make some caps to suit no problem , if you use adjusters which are to long you may upset the rocker angle a bit to much , but its trial really , the harley valves are very good and i have used in ariels
I'll make some caps while I'm waiting for the Valves to be delivered and decide whether to use them when I assemble the head. I'll try 304 stainless to begin with - I don't think that its going to be much softer than the ends of the rockers which I can run a file over.
Just reading this thread out of interest and think I read somewhere about 'lash caps'. There seems to be a lot of them online.
Dave.
:) :) :)
Thanks for all.
The only other problem that I can see is the fact that the valve springs will be already compressed by about the diameter of one spring coil before its compressed even further by the rocker action. Will that over tighten and weaken the spring?
Mike 8) 8) 8)
I didn't realise that they were called lash caps and have managed to find a few that will fit 3/8 valves online. Unfortunately they seem to be mainly in the US or Australia.
I made a couple this morning and will probably also try some silver steel.
If valve caps aren't used then the difference in rocker angle is 3.6 degrees, but this is in the direction of the compression so it should be Ok -the Sloper isn't a precision instrument after all. I intend to try using valve caps anyway though.
In terms of the spring compression then it should only become a problem if the elastic limits are exceeded. So with respect to an extension spring you can keep pulling it apart and if you don't pull it too far then its fine. But if you pull it only once over it elastic limit then its permanently deformed.
I put some old A10 springs in a vice this morning and fully compressed them. They then sprang back to exactly the same length. If you watch the valves open and close on the Sloper then they don't descend very far and are no where near fully compressed. So there really shouldn't be a problem. At the end of the day the springs will weaken over time and to put things in context, then when the Sloper stops one of the valve is always left open. Hence the machine will have a set of Springs fully compressed for a relatively long period of time. When I restored my Sloper the exhaust valve springs were much shorter than the inlet, because it had been left with the exhaust valve open.
unlikely to make a difference , the valve maybe lighter , the distance you state would be about 3 too 5lb higher fitted so should not damage the valve train
:) :) :)
Gotta say that info about the springs is very valuable and certainly puts my mind at rest to a large degree.
Thanks
Mike 8) 8) 8)
if you send me the spring i can tell you exactly the lb it is when fitted and when open if you know the lift , this is not a hi reving motor and the lighter the valve train the easier on the motor , some valve springs are far to hi for the weight of the valve and expected rpm , its just wasting power and waring cams .
:) :) :) :)
Thanks for the offer but I reckon we just about covered this one. My only concern was the fact that with the shorter valve stems the springs would already be compressed by 1/10th inch then they are further compressed by the cam/rocker action which might make them harder work for the rocker arms etc.
Mike 8) 8) 8) 8)
as long as they do not go to near spring bound it will be ok
:) :) :)
Thanks again. I understand what you mean. Must confess the jury is still out on this one and in all honesty the cost of new valves is not a great addition when taking into account the overall cost of a complete engine rebuild. We'll see.
I'm having difficulty making a decision on this one.
Mike 8) 8) 8) 8)