had a search and cant find what im after....
how much bore wear is too much?
running my nail up the bore it slightly bumps but doesnt catch/stop
looks to be where the top ring stops.
How Much Bore Wear
Started by
ginigwunkle
, Nov 09 2007 08:07 PM
7 replies to this topic
#1
ginigwunkle
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Posted 09 November 2007 - 08:07 PM
#2
duncancallum
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Posted 09 November 2007 - 09:43 PM
you cant do it by feel you need to chek for ovality (If thats even a word)
as the engine rotates the piston is forced against one side of the bore and as such this wears faster.
if you can feel wear i would sugest it wants a rebore as a hone will just make it to big for that piston size
as the engine rotates the piston is forced against one side of the bore and as such this wears faster.
if you can feel wear i would sugest it wants a rebore as a hone will just make it to big for that piston size
#3
sixwheeler
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Posted 09 November 2007 - 10:56 PM
Standard rings will be fine for a moderate amount of wear.
Everything that I have ever rebuilt has had a wear ridge at the top of the bore and it's something that I just don't worry about; not had a problem yet.
I thought (but I may be wrong, don't have one handy) that the Haynes manual gave you the dimensions of the bore and wear limits in the engine spec section?
To measure it you need a dial gauge that has legs that point out horizontally.
If you can hardly feel the ridge and the engine was not suffering before it was taken apart then I wouldn't worry about it. The ovality is probably more of a problem, but again, never had a problem.
Make sure (assuming the engine is stripped) you run a glaze buster down the bores before you rebuild it.
Everything that I have ever rebuilt has had a wear ridge at the top of the bore and it's something that I just don't worry about; not had a problem yet.
I thought (but I may be wrong, don't have one handy) that the Haynes manual gave you the dimensions of the bore and wear limits in the engine spec section?
To measure it you need a dial gauge that has legs that point out horizontally.
If you can hardly feel the ridge and the engine was not suffering before it was taken apart then I wouldn't worry about it. The ovality is probably more of a problem, but again, never had a problem.
Make sure (assuming the engine is stripped) you run a glaze buster down the bores before you rebuild it.
#4
ginigwunkle
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Posted 09 November 2007 - 11:00 PM
the heads off, wasnt goin to strip unless rebore......shall chack for ovality and haynes for measurements...thanks for that!
whats this glaze buster? where do i get from?
whats this glaze buster? where do i get from?
#5
sixwheeler
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Posted 09 November 2007 - 11:10 PM
the heads off, wasnt goin to strip unless rebore......shall chack for ovality and haynes for measurements...thanks for that!
whats this glaze buster? where do i get from?
If you are only changing the head gasket and the engine was running ok prior then ignore the whole thing.
Glaze buster removes the glaze from the cylinder bore walls - it is imperative to use a glaze buster (hone) the bores if fitting new piston rings.
The roughness that using a glaze buster leaves on the cylinder bore walls allows the piston rings to bed in and therefore function properly. While on the subject, never let a rebuilt engine idle for more then 10 minutes else you may have a problem with the rings. Best thing you can do with a rebuilt engine is to drive it normally straight away and give it a bit of work to do, and use a running in oil.
Back to the question! Glaze buster is tool with 3 grinding stones that are spring loaded so that the stones are forced outwards. Connect to end of drill and run up and down the bores.
Machine Mart
Edited by sixwheeler, 09 November 2007 - 11:11 PM.
#6
icklemini
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Posted 09 November 2007 - 11:34 PM
- thats a 'honing tool' and can easily rip out far to much metal.. i use a flex hone - far better in my experience.. (http://www.brushrese...rushes.php?c1=2)Glaze buster is tool with 3 grinding stones that are spring loaded so that the stones are forced outwards.
if you have a noticable step - then measure the bore.. i use a dial bore gauge.. set it to what the bore should be sized at, then measure the wear and how bad its out of round... any more than 0.006" piston to bore clearance (on a worn bore) then the rings are gonna do a lot of work - sure the engine will run - but its not the best foundation for performance...how much bore wear is too much?
#7
ginigwunkle
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Posted 09 November 2007 - 11:49 PM
i think i may get the engine rebored as theres no rush,
then when thats all finished and running ill get my 1445 out and fit the new cam and gearbox!!!!
then when thats all finished and running ill get my 1445 out and fit the new cam and gearbox!!!!
#8
sixwheeler
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Posted 09 November 2007 - 11:52 PM
- thats a 'honing tool' and can easily rip out far to much metal.. i use a flex hone - far better in my experience.. (http://www.brushrese...rushes.php?c1=2)Glaze buster is tool with 3 grinding stones that are spring loaded so that the stones are forced outwards.
Yes, you are supposed to be honing the bore! And no it does not take out too much metal, barely touches it, it all depends on the grit grade of the stones, the pressure that is used and the speed that it is used at.
The flexi-hones are quite good, but hard to get hold of and not quite as versatile.
My other one had gone walkabouts so bought one of those as I needed one in a hurry and was then frustrated at how little work it was doing!
I forgot, the aim is to get the honing pattern at 45 degrees.
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