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Cant get pistons out
Posted: Sun Nov 29, 20 10:47 am
by TIB3300
Hello
I have an engine with new rings fitted to the pistons and want to take them out , but the bore has a lip and the rings wont go past it.
This is a new problem to me, done a bit of reading up and seems I may need a ridge reamer. Is there another way to get them past?
and If I was to buy a ridge reamer what's best but not silly money as will probably only use it this once
thanks
Re: Cant get pistons out
Posted: Sun Nov 29, 20 10:53 am
by Pete
Well, the previous owner managed to bash them in past the ridge to get them in....
If the ridge is that bad, then I bet the motor needs a re-bore anyway....
Check the Bores along the thrust line with an expanding Micrometer to see what the wear on the bore is like.
Bore to piston skirt clearance should be around 0.0035 - 0.004"". I bet your Ridge is more than that if you can't get the pistons out...
Plan "C" time, I fear.....
Re: Cant get pistons out
Posted: Sun Nov 29, 20 7:44 pm
by TIB3300
Pete wrote: Sun Nov 29, 20 10:53 am
Well, the previous owner managed to bash them in past the ridge to get them in....
If the ridge is that bad, then I bet the motor needs a re-bore anyway....
Check the Bores along the thrust line with an expanding Micrometer to see what the wear on the bore is like.
Bore to piston skirt clearance should be around 0.0035 - 0.004"". I bet your Ridge is more than that if you can't get the pistons out...
Plan "C" time, I fear.....
Nope still, plan B.1 but with rebore and new pistons maybe???

Re: Cant get pistons out
Posted: Sun Nov 29, 20 9:12 pm
by Pete
Quite possibly, and a re-balance.
Worth looking at a stroker rotating assembly as once you have weighed up the parts and machining cost you are not a million miles away from a 440 source unit - and it is all new and balanced with rings and bearings.
You really need to check everything that the previous owner has done / had done, as they clearly have cut corners on the Pistons / Rings and Bores.
That timing set does not look great either - hard to see from the pictures but I would only ever fit a double roller if I was not using Gear / Belt drive....
Re: Cant get pistons out
Posted: Wed Dec 02, 20 6:47 am
by TIB3300
Pete wrote: Sun Nov 29, 20 10:53 am
Well, the previous owner managed to bash them in past the ridge to get them in....
If the ridge is that bad, then I bet the motor needs a re-bore anyway....
Check the Bores along the thrust line with an expanding Micrometer to see what the wear on the bore is like.
Bore to piston skirt clearance should be around 0.0035 - 0.004"". I bet your Ridge is more than that if you can't get the pistons out...
Plan "C" time, I fear.....
After speaking to a chap at Sheffield engine sevices. Was to to bash them!! well what do you know, came out.
Bit of lube and a bit more enthusiasm

I was worried of more bad news by breaking something.

Re: Cant get pistons out
Posted: Wed Dec 02, 20 11:12 am
by Pete
TIB3300 wrote: Wed Dec 02, 20 6:47 am
I was worried of more bad news by breaking something.
Remember: "Measure, Measure, Measure".
You will probably find that the bore is excessively worn and that the Pistons and Rings you have just removed need replacement in any case.
I would imagine a re-bore is on the cards if the Ridge is that big....
Re: Cant get pistons out
Posted: Wed Dec 02, 20 12:23 pm
by Dave999
This might work
if you have an old set of feelers...
or a cheap Chinese set
oil them
if its worn they might well go in bit of wiggling
piston down an inch
ram 3 feelers between it and the bore 120* apart. they will get pushed out but you just need the first ring past the ridge before you re apply wtice more
push piston up
it might save the rings
but if it needs a rebore anyway hone or abrasive paper over the ridge to smooth the way
last resort welly them out
Dave
Re: Cant get pistons out
Posted: Wed Dec 02, 20 1:22 pm
by TIB3300
Pete wrote: Wed Dec 02, 20 11:12 am
TIB3300 wrote: Wed Dec 02, 20 6:47 am
I was worried of more bad news by breaking something.
Remember: "Measure, Measure, Measure".
You will probably find that the bore is excessively worn and that the Pistons and Rings you have just removed need replacement in any case.
I would imagine a re-bore is on the cards if the Ridge is that big....
Looking at it with the pistons out, its not that big a ridge. It was just with it having new rings in it,, it was tighter then old rings.
But yes will "Measure, Measure, Measure".

Re: Cant get pistons out
Posted: Wed Dec 02, 20 4:22 pm
by TIB3300
Pete wrote: Sun Nov 29, 20 9:12 pm
Quite possibly, and a re-balance.
Worth looking at a stroker rotating assembly as once you have weighed up the parts and machining cost you are not a million miles away from a 440 source unit - and it is all new and balanced with rings and bearings.
You really need to check everything that the previous owner has done / had done, as they clearly have cut corners on the Pistons / Rings and Bores.
That timing set does not look great either - hard to see from the pictures but I would only ever fit a double roller if I was not using Gear / Belt drive....
Have you seen this make befor? any good ?
Re: Cant get pistons out
Posted: Wed Dec 02, 20 5:11 pm
by Pete
Personally I would not use one of those = I think they are called a "Hyvo" style and are designed to run more quietly - they are of cheap manufacture and I would only use a Double Roller Timing chain or a Belt or Gears.
It is amazing how quickly the set ups wear in a v8 with no tensioner, but they seem to keep working...
Re: Cant get pistons out
Posted: Wed Dec 02, 20 6:35 pm
by TIB3300
Pete wrote: Wed Dec 02, 20 5:11 pm
Personally I would not use one of those = I think they are called a "Hyvo" style and are designed to run more quietly - they are of cheap manufacture and I would only use a Double Roller Timing chain or a Belt or Gears.
It is amazing how quickly the set ups wear in a v8 with no tensioner, but they seem to keep working...
Thanks
Where would one get a Double Roller chain ?
What name to look out for?
Re: Cant get pistons out
Posted: Fri Dec 04, 20 9:10 am
by Dave999
I used Romac aussie gears with German IWIS chain.
also sold in the US for 318s etc under the ROLLMASTER brand
the one you took out looks like an aftermarket copy of the standard type or maybe the standard one. nothing wrong with them but better exists for little extra outlay and much less stretch in use
Dave