Yes that 634 engine is typical IH, Dry liners have some very good points but changing liners aint one of them. Of course IH argued that by changing liners A. you never took any metal out of the basic engine block an B.you can do it with the engine still in the frame, which of course you can with something thats been running all day every day. Sadly not the situation with this dear rusty old gal. Thanks for info already have a puller.

Mike

 

Thanks again

Derek.They are cast pistons. I dont mind welding cast but the position would render it imposible to "crack check" the weld.

Chaz. I'm currently discussing this with the Co you suggested the other day. The thought at the moment is to make a liner to fit the existing piston. That would be £145 plus VAT. So now at least we have a direction of travel

Mike 

 . is 

Hi Thanks for your replies.

I am upsides with the problem and the normal answer is destruction of the existing liner and a refit. I was hoping to avoid that if possible.

The professional answer is if the pitting is below the point to which the compression rings descend. Hone it and ignore it. If not then A. Take a chance on honing , or B.new liner. So basically where I was anyway.

Mike

 

Hi All. This is not BSA but it could have BSA implications, tho in truth I am looking for inspiration and advice.

The situation is thus. I have a 1943 Farnall Tractor engine that I rebuilt several years ago. Then sold the tractor. The buyer died and said machine was left standing out with no cover on the upright exhaust pipe. So a cylinder got filled with water and the piston rusted in etc.

Have freed the piston and stripped engine which is dry lined. The place in the bore were the piston was rusted in became badly pitted as a result. The piston is not too clever but can be carefully cleaned and reused. Almost all of this model was modified by fitting a lager bore liner. This one isnt modded and no original liners available. The Mod is 1/16 larger The cost of replacing all 4 liners etc is relatively prohibitive.

Now I have thoughts of "repairing" the cylinder wall with the liner in situ. In other words filling the pitting. My thinking has gone down the routes from Something like JB-weld to silver solder. In truth I believe it only needs something to diminish the risk of the pitting breaking the rings.

The pitting is probably too deep to rebore and new pistons are not available. So gents how about coming to the aid of an oldish man and donning your thinking caps.

Again apologies for using the site for this. but I know a lot of us have had similar problems.

Mike

 

That  chip certainly wouldnt bother me too much. A lot of the old singles (and new ) had a larger piece than that cut out purposely for the conrod to clear the liner.

Just make sure that there is no extended crack from the space,

Mike

 

I would have thought that the difference between 75mm and 76mm is only 040". Perfectly happy to be corrected.

Mike

 

I reckon in that case you are going the correct way about it. I wanted 7.5  compression pistons---I think £320 plus postage plus Vat
Plus some funny looks from across the room.

Mike

 

I know that A50 pistons are difficult to obtain and I think my last set were hells expensive. By the time you have paid for new pistons and rebore, its almost as cheap to have the engine resleeved/lined to fit the pistons. Dependant of course on wear and condition of old pistons. I had a Sloper done that way last year. However in this case I also had the piston refurbished to std.

I truth I dont know whether or no this would work in similar situations. My thoughts are that if you can fit rings below the depth/groove level that should be OK.  8)Depends on usage but I would think OK for 20K miles or so.

Mike

 

Really only peripheral to this discussion. I was told many moons ago, that when reassembling heads, put a slight film of sealant around the valve guide under the lower washer. This will stop any seepage taking place at the valve guide/head casting joint. I've used it but of course its impossible to quantify its real use value. My thoughts are that I have nothing to lose by doing so.

As for valve guide liners of any type. To me that is preferable because it should retain the original spec more easily and it cannot place any stress on the " valve guide/head casting interface". It is usually cheaper and quicker. BUT use great discretion with open valves. In fact I know of a couple of engineers who will not fit them unless you sign a disclaimer and at least one who will simply not fit them to open valve engines.

As for the issue under discussion: no real idea and I've used or not used according to Head Type instructions.

These are simply my observations/thoughts and honestly not possible to prove either way

Mike

 

I often wonder how my old engines ran when I was much younger and didn't know about such things as ring gaps.

Mike

 

I would uggest your best way forward is to have new seats. If so its a short step to new guides or guide inserts. T&E engineering Bedford has done a couple for me over the years. They'll grind the valves in for you at the same time.

There are of course several reputeable machinists across the country who will happily do the biz for you. I would further suggest that such may not ultimately be that much more expensive.

Mike

 

Just a point on bolts 'bottoming out'.

I had the situation, self inflicted with a 'blow' front RH side of head. Retorqued started motor still blowing. Removed head checked to ascertain head and barrell were good--yep  :'Annealed gasket. Refit, re-torque still blowing. Removed the head dug around with a screw driver in all the bolts holes. Crap in the front RH corner bolt hole. Cleaned, flushed (this gets boring). Bolted up, started--- solved--- as I said self inflicted. It really is a B when you cant find anyone to blame.

Mike

 

I am having trouble with the log in system. I come up as guest. Do all the biznis and log in.forever. then 2/3 times down the line I hve to go through the same rigmarole again. I can understand when DVLA screws me up, but not dear ol' BSAOC.

Advice please.

Mike

 

For your info. At Southampton Hospital the prostate cancer staff used to hold a "forum" about every three months where like me who had it done could meet with those who were just going down the route.

I think its worth while checking if your area is doing anything similar because it was well worth while.

Take care

Mike

 

Understand now. thank you.

Mike