Yes, calver sells the Iwis, super high quality chain. there are even differences in the quality of Iwis chains from what he says so take note. 

Sadly any timing chain in a UK box now seems to be rubbish.
In order of excellence I rate German chain (Iwis or other), Japanese chain (OCM) then all the rest, UK chain last.

Yep! That might be my problem. This block has been in-bored already. I am getting a new super high quality chain (for my Swiftune adjustable setup) as the last two chains I have gotten have stretched. Another piss poor item to add to the list of parst that just not what they used to be.

IMO .005-.006" would be fine.
I have seen too many 1275s spin centre main shells over the years, and need an align bore job on the mains to save the block. Which gives another problem, loose timing chain....

That is exactly what the machine shop said. I cant remember what I set the endfloat to exactly. I just need to go back over my notes to find it. As I could not remember before I went to the machine shop, I searched online and found a MM video on it where they say .002" is correct. When I told the guys, they were very sceptical. I believe I set mine to .004 for some reason. I do not rev the motor to anything bast 6500. I'd actually say that 6 is the usually the max as its just not pulling anymore. I drive this car hard though. When I was doing a lot of AutoX events, I would use every rev it would allow but that was usually all done in second gear.

I'll have to go back over and see what I set it at. As I am technically not racing this car, maybe .005-.006 would be a good number to shoot for?

IMO the .002-.003" endfloat in the book is too little for an engine that is going to rev past 6500. After my fresh 1360 spalled the thrust washers and almost spun the center main shells, I increased the endfloat to .006-.007" on Graham Russell's suggestion. I've had no problems since.
Historic group Nb race motors here in Oz get .007-.008" endfloat when built. 

I did not replace the arm or plunger. Both were in perfect condition. I also made a tool/spacer to set the throw by. I believe it was 10mm but would have to go back to the book.

Did you replace the plunger and short throw out arm at that time? Steve (CTR)

This is an A+ SPi car with the stock flywheel. I had the clutch resurfaced and I made sure they knew to machine both the surface as well as the mounting posts as well. To be sure the distance is the same. I then lapped the flywheel onto the end of the crank with some fine paste before mounting. I even took the time to buy multiple clutch housing gaskets to get it all in spec.

I talked to Mike about the thrusts and he has never heard of this before. He looked my order and found that it was 2.5 years ago so there is no way to check their current stock. I guess it is just a note to all to check EVERYTHING even if it comes out of a fresh package:-)

What clutch flywheel are you running? How was it set up? You might check and find those thrusts were supplied that way on purpose. Coming from mini sport? It's a common practice why not sell them that way? I'm not sure if it's trash in your oil or a clutch release problem. The combination of parts used can be a problem. I have even found some new parts when used together won't release. Steve (CTR)  

I dont have any pix of the motor/cfrank as its now with the machine shop. Sorry.

The thrust washers were bought from Mini Sport about 2.5 years ago. Both the set that is in the block as well as the brand new set that is in my hands. Both sets measure the top thrust being 5 thousand thicker then the bottom set. This was not my intention. On the clutch side, the thicker top thrust took the most abuse as the lower probably wasnt doing much work.

What I would love to figure out is what caused my thrust surface on the clutch side to get grooved. Was it just metal filings in the oil? Preload on the clutch? That is what I need to know to ensure this doesnt happen again.

To figure this all out I wanted to provide the basics; the crank endfloat was spot on, the primary gear endfloat as well. The primary gear and spacer both look perfect. No major wear (trying to rule out clutch preload).

Steve, this was a brand new crank with all standard bearings and thrusts. I now have a pretty nice collection of cranks sitting in the attic. This makes 3 total. I believe this last one is fine, other then the thrust surfaces. The first and second would both need a regrind. I figure at some point, new cranks are going to run out, the US prices are too high and sending a core back to the UK would be too expensive so I am hoarding them:-) I really dont need 3 though.

At one time in my life I liked to hear the little engines at 9000 rpm not a lot just short burst. Used matching thrust on clutch side double gray. Trimmed the lower half of front thrust. The poor little cranks flex so much they pinch the thrust on the down strokes of two and three. I think he claims he started with a new crank and new thrusts? Wear showing only on lower half? I had a cracked crank that acted like a fly cutter and milled the thrust on that side .060 till the counter weight started hitting the block, sudden knock. Steve (CTR)

re the differing thrust thicknesses-
Some race engine builders here in Oz (eg MADMAT) deliberately use thinner thrusts in the centre cap than in the block. This is to avoid putting  bend loads on the cap when using competition clutch diaphragms. The thrusts probably have a shorter life, but that's OK for track use.
I've never seen the need for it, but I've only built fast road engines- an orange dot spring is as heavy as I fit. So I keep them the same, top & bottom.

I have read this thread several times each day. Still having a problem understanding the issues and how you got where you are. I'm thinking a few pictures of your thrust washers from both sides and the thrust face of your crank will help. If you intened to buy a new crank I'd be interested in your old one to experiment with. We have remachined the thrust face and fitted over size thrusts. Also have welded up bad thrust and machined to std spec. While not pretty work if done correctly it can save a crank. Pictures please? Steve (CTR)

I certainly didnt install the thrust washer wrong. They can only go one way really with the bottom ones have the little "ears" on them. They were all facing the right direction as well:-) The issue I see straight away is that these brand new washers were not the same size. The brand new ones I took over to the machine shop today were the same. The "non-eared" top thrusts, both front and rear (or non-clutch and clutch side) were of different thicknesses. Strangly, both had the top thrusts were 4.5-5 thousand thicker then the bottom ones.

My question is that as I go to rebuild this motor, I want to try and figure out what is going on and what caused the wear in the first place. This is a A+ injection motor.

Spank, I remember raeding about your busted cranks during the Lemons runs. I think I was going to send you one of my cranks to reuse at one point actually:-) What happend, i have no idea.

The machine shop is going to pre-assemble the motor in different stanges to check for endfloat. I was very anal when it came to setting and followed a series of articles that Keith Calver wrote to the T. I guess all is lost if you are setting it with different sized thrusts though. Your way of checking and rechecking sounds brilliant though. I would have never thought about the points of the C touching bit it makes so much sence. We all need to be really careful these days with the poor quality of parts coming out of even the biggest names in the game. A shame really.

I asked the shop about having the thrust surfaces reground and he said that he would seriously recommend going the new crank route. I dont have a person relationship with any crank guys but these guys dont have anything to gain (actually losing money on time going the new crank route) by this advise so I cant argue it too much. What do you think the cost of having the thrust surfaces touched up would be? A brand new crank (no core charge) and with new bearings is 365isg USD from over the pond. I have to make a large order anyway so the shipping will be eaten up by everything anyway.

I am not one to keep my foot on the clutch, ever. I drive with my right foot ready to pounce on the brake for the most part:-) Funny thing is, if my foot rest ever-so-slightly on the clutch, enough to take the slack off the clevis pin that attaches to the master, it makes a very faint rattle/buzz sound. I was going to do something to fix that but its a fine reminder to get your bloody foot away from the pedal. I dont think anyone else would ever notice it but I can. A strange bunch us petrol heads are, right?

I get what you mean about the trust surface coming into play only with the clutch depressed but I have the motor totally stripped. That would bother me that I didnt repair something that is wrong, and could get worse. Maybe that is just me.

I'm not super clear on what you are asking or what's going on, but I'll share my practice with regards to thrust washers and crank thrust surface. Others will likely offer a different input, so just chuck my advice in the same pile as theirs.

1) when I install a crank into a block, I check crank end float FIRST by installing ONLY the block-side thrust washers in place, no center cap at all just main bearings plus caps torqued at 1&3 (obviously no cap main bearing at #2 aka center, just the block main bearing there). Next, I put the center main cap and bearing but still no cap-side thrust washers. Again, I check for float using a dial indicator (I don't bother with feeler gauges). Then I put the thrust washer in the clutch-side of the main cap and I check end float again. I make sure (for me and my personal thinking) that I want the block side thrust washer hitting a half-thou or thou or so before the cap thrust makes contact. To me, the block side thrust can take the load better than a cap thrust that's just there by means of 2 bolts and some locating dowels. The final step is to put cap side thrust in the non-clutch side. I sand the cap side thrusts (with flat surface and sand paper) so the clearance is the same as it was with just the block side thrusts installed. Ideally, both thrusts will hit at the same time but if the cap is undersized then more than likely after a few uses of the clutch pedal, they will both hit crank thrust at the same time.

2) when I finally install the cap-side thrusts, I have check to make sure that after torquing the center main down the top side thrust washer can be wiggled by pushing on it's locating tang. Just looking for some evidence that it's not pinched. Sometimes the top and bottom thrusts will contact each other at the open "C" tips like this () and squish together and then deform the thrust washers. More often than not, especially now-a-days with new thrusts, I need to file the tang of the top thrusts so they dosn't bind in the cap and I also need to file the open tips of the thrusts so the tops and bottoms don't bind against one another when the main is torqued up.

3) My crank guy smooths out thrust faces on my cranks and will grind off a bunch when I ask him to. In my LeMons 1275 motors, I use cranks that others have discarded because they have grooved up the thrust faces (usually because someone installed a thrust washer in backwards or didn't set their clutch diaphram up correctly). The crank grinder will sometimes ask for a cap and the thrust washers I want to use and the clearance I want. But typcially I tell him to take off just enough to clean up the face and then I make my own proper-sized thrust washers to fit that crank. I've done some goofy-$hit including using some old head gasket material to back thrust washers to get them thicker (worked just fine!), but I now just buy the oversized thrust washers and sand them to size (if it's just a small amount) or have the machine shop surface-grind some oversized ones to the thickness I give them if it's more than I feel like sanding at home.

I have NEVER had a failure at a center main from a crank had it's thrust surface machined smooth. Even on a non-hardened Austin America crank with a .040 main bearings, the rods turned to S sized, and the entire raised lip of the thrust face machined off of the clutch side. This is in a motor that people beat on for 10-14 hours a weekend mostly at 4000-6800 rpms. I HAVE had broken cranks at the flywheel side #4 rod of stock cranks that were turned to S size, but I was also using one of those ultra-light old school Minispares flywheels that Vizard said give weird harmonics (and that aren't made any more). Probably goes without saying that I believe him. I got about 30 track-hours out of the cranks before they broke. I switched to a heavier flywheel and haven't had a problem since. (the same block that broke 2 cranks has the 3rd crank in it with over 45 track-hours on it and I did nothing to the block-- I didn't even pull the pistons or rods out when I put crank #3 in it-- just new crank, bearings, thrusts, and replaced flywheel assy).

On a recent rebuild of the motor of my Traveller I installed different thickness thrust washers to get the end float within spec. In your case, the thrust washers must have been installed wrong if the top and bottom are different thicknesses. Swarf must have cuased the grooves. I would not bother repairing the thrust faces because they only come into play when the clutch is depressed but you need to start putting the transmission in neutral traffic lights.

I am about to be on my 4th crank in this one block!! Crazy I know. Its a long story, but I have the block at a really good shop now so I have some faith. They discovered a very interesting thing, the thrust washers were not the same thickness. Both top thrusts were thicker then the bottom ones. Totally strange and alarming. They were brand new when installed with a brand new crank. All standard size. When I torn the block down, the endfloat was still spot on. The probelm was that the top, clutch/rear thrust had wear marks and so did the crank. Very easy to feel grooving around the thrust surface. Now, I know they sell oversized thrust washers but is having the thrust surfaces repaired really an option? Cost wise?

The next question will likely be why the thrusts worn and groved the crank. That I need to sort. The clutch didnt show any major slippage wear indication a constant load, I believe I checked that there was freeplay when released. The primary gear bushings and bronze spacer both look perfect. Endfloat of both the crank and the primary were tripled checked when installing with a dial gauge as well as feelers to be sure.

Now, the fact that the thrusts were different thicknesses is a bit alarming but could that be a reasone for the wear? The thrust surfaces on the center cap are very flat and accurate. The shop is going to check the line-bore to be sure it correct but the thrust looked evenly worn across its entire surface. This motor is in for a full rebuild. Had excessive leak down and I actually noticed one piston ring had chipped. Bores and piston are scored. None worse then the others though. Piston 3 (which is over the rear thrust) had the same as others. Crank bearings looked to be in good shape. I just want to try and rule out everything I can while the shop has the block.