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Post by stusco on Jul 19, 2024 17:31:04 GMT 1
Would you class this as blowby   |
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Blow by
Jul 19, 2024 17:40:11 GMT 1
via mobile
Post by midlifecrisisrd on Jul 19, 2024 17:40:11 GMT 1
Yes
New rings as a minimum
Steve
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Post by arrow on Jul 19, 2024 17:43:28 GMT 1
Looks pretty normal to me. The intake side looks good.
You will always get that appearance on the exhaust side because as soon as the exhaust port begins to be open, the whole of the piston area exposed to that port will be exposed to the burnt gas.
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Blow by
Jul 19, 2024 17:44:02 GMT 1
Post by stusco on Jul 19, 2024 17:44:02 GMT 1
Ill get my micrometers out its not done that many miles i was surprised when i pulled them ,the thrust on the crank is about 0.65 on one side and 0.35 on the other could get spendy
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Post by donkeychomp on Jul 19, 2024 21:18:48 GMT 1
I was expecting a reference to Hugh Grant there...
Alex
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Post by reedpete on Jul 20, 2024 1:34:18 GMT 1
Yes… and to be specific why… for starters ignore the pistons, the tell is the carbon on the rings and probably also on corresponding parts of the bore . That implies that a section of the ring is not in contact with the cylinder wall. If not in contact with the cylinder wall then combustion charge can and is blowing by the rings..
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Post by stusco on Jul 20, 2024 7:26:18 GMT 1
The bores are spotless still have the criss cross from the hone I didn’t take a picture as there was nothing to see
ill take more pictures
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Post by Tobyjugs on Jul 20, 2024 9:24:40 GMT 1
Hi Stu measure the cylinder and piston skirts. In the top picture on the right hand piston. It looks like light is shining through the underside of the top piston ring groove (yellow) check to make sure the ring grooves and pistons are still in tolerance.
What do you mean by thrust on the crank?
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Blow by
Jul 20, 2024 10:54:10 GMT 1
Post by stusco on Jul 20, 2024 10:54:10 GMT 1
Checking the gap at the thrust washers either side of the big end (D in the haynes)
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Post by stusco on Jul 20, 2024 13:20:52 GMT 1
 Head colouring |
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Post by stusco on Jul 20, 2024 13:22:49 GMT 1
Thrust washers  0.65mm limit is 0.75 |
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Post by stusco on Jul 20, 2024 13:24:03 GMT 1
 0.35mm min is 0.25mm |
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Post by stusco on Aug 6, 2024 18:25:21 GMT 1
Ive got my pv engine it bits at the moment, when i checked the gap on the rings i went to push them down with the piston skirt ,but the piston wouldn’t fit in the barrel both barrels and piston are the same they can go in from the bottom but won’t go all the way through ,the engine has done a few thousand miles like this ,when they were rebored they came with the pistons in the barrels ready to go so i just fitted them with no problems , looks like both barrels are tapered
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Post by jon on Aug 6, 2024 21:50:00 GMT 1
Pistons are tapered so they are a small diameter at the top than the skirt. Therefore they will fit in the bottom of the barrel better than the top.
This is because when the pistons get hotter at the top than the bottom the top expands to the same diameter as the bottom.
As far as I know the bore should be parallel.
Jon
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