xr-stu

right, after deciding the horrid noises coming from my puma engine must be crank related, ive got myself a replacement engine and plan to rebuild it the week after next. ive sorted main and big end bearings, and a full engine gasket/seal set, and im awaiting a price for piston rings and oil pump. i have just fitted timing belt, water pump, all new tensioners and idlers for the timing and auxillary belt to my current (knackered) engine, so and as theyve only done about 300miles ill be re-using them.

im happy with the basic fundamentals of the stripping and rebuilding process but id just like some clarification on a few things,

tolerances and whats acceptable, do they vary from engine to engine, or is there a generally accepted standard for bearings and ring gaps etc
honing the bores, is it required and the best procedure
assembly lube (a thick oil or a grease?)
initial start up and running in
what solvents and cleaning processes are best, or to be avoided

and any other general advice. as i said im happy with the basics, ive done heads before, lapping valves etc, but not done a proper rebuild and want to make sure its done 100% properly!

Chip

iTrader: (3)

They vary a bit from engine to engine, but there are general rules of thumb you can work too if you cant find the specific data for that engine etc.
Like a four thou per inch of bore on ring gaps is not a bad ballpark, 2 thou for main bearings etc


Yes its required or the rings wont bed in, if I were you I would use a flexhone rather than a 3 prongy thing, I have one somewhere right size for that engine I think but will need to check.

Its not a bad idea, but on just a quick freshen up like that engine oil will be fine to assemble with IMHO

Keep revs low initially, vary load though, lots of on and off the throttle.

Brake cleaner is cheap and cheerful


not sure if its the replacement engine you are rebuilding or the original one?
Id not bother with crank grinds and stuff on such a cheap engine to replace, so I would only start with what seems like a decent working one in the first place, although then you have to ask if its worth bothering to rebuild anyway as you arent really improving anything anyway by a significant margin!

xr-stu

cheers pal. its a replacement engine ive ripped out of a breaker ill be rebuilding. theres only the very very faintest of tapping, a friend of mine and the mechanic from the garage next door didnt even think it was there lol. it doesnt smoke so doesnt seem like a bad base.

i wont be bothering with rings or oil pump now as its going to add about Ł500 to the cost of the rebuild. ive found out that eurocarparts has never even sold a pump or rings for this engine, and dont even have a part number setup for them. which suggests to me that if they of all companies have never sold one, then i wouldnt imagine they fail very often. like i say, it doesnt smoke at all so the rings should be fine in theory.


as for the bearings, i will plastigauge them but again, as theres no nasty rattles id assume theres no major wear but itd be good to check, and i wont be bothering with a regrind.


may hit you up for some help mapping it in a month or 2, off to the usa in a couple of weeks and bringing back an M62 and microsquirt.

Chip

iTrader: (3)

Cool stuff.