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GPZ11 Injection
Moderators: paul doran, Taffus, KeithZ1R, chrisu
Re: GPZ11 Injection
If the pistons are matched to the original liners then is it wise to rotate the liner by 90 degrees ?
Just thinking that the fit will be different as the piston/liners were bedded in with the original front/back orientation, and now you'd have changed that ?
Plus, the liners would have been bored at the factory in that original orientation. Don't know whether rotating them would affect piston dynamics at 8000 rpm.
I'm not an engineer, just curious.
Just thinking that the fit will be different as the piston/liners were bedded in with the original front/back orientation, and now you'd have changed that ?
Plus, the liners would have been bored at the factory in that original orientation. Don't know whether rotating them would affect piston dynamics at 8000 rpm.
I'm not an engineer, just curious.
H2B GPZ900R
Re: GPZ11 Injection
The thought behind this is to look after the out of round tolerances for the future (so it wears the smallest diameter 're-rounding' it. The liners will be honed once back in place, then re-measured and checked against the tolerances. The rings then checked in the bores. With the honed bores everything should re-bed. It possibly won't help at all but I can't see how it would harm?
Would be interesting to see other peoples, more experienced, views on this.
Would be interesting to see other peoples, more experienced, views on this.
Pete
Re: GPZ11 Injection
Hi Pete
if you didn't rotate the liners yet, don't do it!
If you did rotate the liners it would be wise to have them rebored with oversize pistons.
Honing after rotation of the liners will do no good.
If the liners are still in their original position and if the diameter is within specs, just hone the liners and put new piston rings on the pistons. You'll get better and safer results.
GrtZ
Philippe
if you didn't rotate the liners yet, don't do it!
If you did rotate the liners it would be wise to have them rebored with oversize pistons.
Honing after rotation of the liners will do no good.
If the liners are still in their original position and if the diameter is within specs, just hone the liners and put new piston rings on the pistons. You'll get better and safer results.
GrtZ
Philippe
the differences between a little boy and an adult man is the price and size of their toys!
Re: GPZ11 Injection
Philippe, the liners were removed because I thought the spares, wrongly, were in better condition. I have no idea what the rotation was. Rob mentioned that liners could be moved from one set of barrels to another, and with the work he's done that I've seen on here, I trust him 100%. Once the liners go back in they will be honed and measured etc. I see no reason from a logical engineering perspective why this shouldn't be fine, but I am completely open to a slapping if accompanied by an explanation why not.
I've seen posts where people have had liners so loose they can rotated cold, now although that can't be ideal, once clamped up, given that they're not that loose and are still a mild interference fit, who knows what rotation they were?
As said before, very open to be slapped down.
I've seen posts where people have had liners so loose they can rotated cold, now although that can't be ideal, once clamped up, given that they're not that loose and are still a mild interference fit, who knows what rotation they were?
As said before, very open to be slapped down.
Pete
Re: GPZ11 Injection
rickm wrote:Plus, the liners would have been bored at the factory in that original orientation.
The early "J" was notorious for oval liners as the factory bored them to size before fitting in the barrel castings.
So the original fitting in the barrels did not rely on accurate orientation, initially.
If rotated 90 degs can't see much issue as you can "mic" them up afterwards?
And on the 7th day... Zeds were created!
Re: GPZ11 Injection
Pigford wrote:rickm wrote:Plus, the liners would have been bored at the factory in that original orientation.
The early "J" was notorious for oval liners as the factory bored them to size before fitting in the barrel castings.
So the original fitting in the barrels did not rely on accurate orientation, initially.
If rotated 90 degs can't see much issue as you can "mic" them up afterwards?
Indeed, I had an '81 J at the time and it drank its share of oil (presumably for this reason).
It'll be interesting to see the if mic readings change at all after re-fitting in the block.
H2B GPZ900R
Re: GPZ11 Injection
Thanks for the opinions. The liners will be remeasured, noted, refitted then measured again. It will be interesting to see how much the measurements change. I'm also going to measure the bores in the cylinders without liners.
I shall post all the results.
I shall post all the results.
Pete
Re: GPZ11 Injection
Hopefully soon. Just waiting on the large o rings that go in the base of the liners. France is on 'shutdown' in August so everything takes it's time. I did all the measurements a while ago and know which liners will go where and in which orientation, just got to drop it all on a spreadsheet.
Pete
Re: GPZ11 Injection
Got the new O rings in. I ordered 79x3mm. In hindsight should have gone for 79x2mm as they shaved the o rings when pressed in. It certainly won't allow any oil creepage (if that's a word). The liners dropped in nicely (liner in the freezer, barrels in the oven to 150c until it got to the o rings. Nipped to a mates who's got a press to finish them off (oven involved).
So a question.
All are seated,3 are slightly proud in places, 1 is slightly proud, we're talking 0.05mm max.
How much does the HG absorb?
I'd rather whip them out again and change the o rings than have to 1/2 rebuild the engine once installed.
Please advise the muppet.
The measurements for out of round are 0.03mm max per cylinder and I'm getting 0.2 to 0.4 on rings, so they should be good to go.
Next job is to get the engine vapoured, then paint, then ring Nick for gaskets.
So a question.
All are seated,3 are slightly proud in places, 1 is slightly proud, we're talking 0.05mm max.
How much does the HG absorb?
I'd rather whip them out again and change the o rings than have to 1/2 rebuild the engine once installed.
Please advise the muppet.
The measurements for out of round are 0.03mm max per cylinder and I'm getting 0.2 to 0.4 on rings, so they should be good to go.
Next job is to get the engine vapoured, then paint, then ring Nick for gaskets.
Pete
Re: GPZ11 Injection
Whereabouts have you fitted the 'O' rings ?
They shouldn't be in situ until the liners are in.
They simply roll up the liner spigot and sit in the shallow groove between the spigot and the bottom of the block.
A bit of oil helps them slide in.
Liners should be flush with the gasket face.
They shouldn't be in situ until the liners are in.
They simply roll up the liner spigot and sit in the shallow groove between the spigot and the bottom of the block.
A bit of oil helps them slide in.
Liners should be flush with the gasket face.
Re: GPZ11 Injection
zed1015 wrote:Liners should be flush with the gasket face.
0.05mm too much then. Back out then and try again with thinner o rings while I'm there.
Pete
Re: GPZ11 Injection
Just fit the liners first.
I presume they are going back in their original block so should drop in flush.
Oil tho 'O' rings and roll them up the spigot and work them into the gap with a small screw driver or similar.
They don't need to be right up there below the surface.
They will get pushed fully home once you bolt down the head.
I presume they are going back in their original block so should drop in flush.
Oil tho 'O' rings and roll them up the spigot and work them into the gap with a small screw driver or similar.
They don't need to be right up there below the surface.
They will get pushed fully home once you bolt down the head.
Re: GPZ11 Injection
Thanks Rob but I must be missing something.
Here is a picture of the spare barrels with an o ring in place
And here's a quick sketch of the cylinder without an o ring as if it's been cut in 1/2 length ways
Liners back out anyway by the looks of it.
Here is a picture of the spare barrels with an o ring in place
And here's a quick sketch of the cylinder without an o ring as if it's been cut in 1/2 length ways
Liners back out anyway by the looks of it.
Pete
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