Hey guys! So while i'm building my 5k, I have gotten to the point of putting the pistons in. I'm using 40 thou over and rings to suit. However, when I compress them with the tool, it doesn't compress right round equally. and so when I try and lighty tap them into the cylinder they instantly bind. Is this a common problem or am I doing something wrong? I've gapped them to their spec. (Everything is well lubed up and this is how I do it at work and no problems)

 

Cheers!

I just gapped a set of rings for my 5k the other day.

What clearance did you do them too?

If you did it properly and they were fine sitting in the bores on their own then the problem must lie in the ring/piston combo! Got a set of verniers? Compare the ring depth to the groove in the piston.

Hi James,

                  Very common problem, with the cheaper type of ring compressors, most of us have.

This video explains the issue perfectly, if everything else you have done so far, is as per the book.

https://www.youtube.com/watch?v=v1bKOQWVOaE

https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=tapered+bore+ring+compressor&_sacat=0

There is also an adjustable tapered ring compressor, which are a lot cheaper, but I've never used one, so can't vouch for it. 

https://www.ebay.com.au/itm/4-000-4-060-Aluminum-Adjustable-Piston-Ring-Compressor/311749924622?hash=item4895be570e:g:hosAAOSwK~RaBQLn:rk:3:pf:1&frcectupt=true

Maybe someone else on here that has used one, might like to comment.

Cheers Banjo 

Edited December 30, 20187 yr by Banjo

On 12/31/2018 at 8:25 AM, Taz_Rx said:

I just gapped a set of rings for my 5k the other day.

What clearance did you do them too?

If you did it properly and they were fine sitting in the bores on their own then the problem must lie in the ring/piston combo! Got a set of verniers? Compare the ring depth to the groove in the piston.

Cheers for the reply Taz, I've been using this  as a guide
piston ring clearance: 
Ring End Gap: Top compression ring 0.10-0.28mm
Lower compression Ring: 0.15-0.30mm
Oil ring: 0.2-0.7mm
Ring clearance in groove:
Top compression ring: 0.03mm-0.07mm
Lower compression ring: 0.09-0.06mm

not sure if that's good or not, what kind of gapping would you recommend? 

On 12/31/2018 at 9:31 AM, Banjo said:

Hi James,

                  Very common problem, with the cheaper type of ring compressors, most of us have.

This video explains the issue perfectly, if everything else you have done so far, is as per the book.

https://www.youtube.com/watch?v=v1bKOQWVOaE

https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=tapered+bore+ring+compressor&_sacat=0

There is also an adjustable tapered ring compressor, which are a lot cheaper, but I've never used one, so can't vouch for it. 

https://www.ebay.com.au/itm/4-000-4-060-Aluminum-Adjustable-Piston-Ring-Compressor/311749924622?hash=item4895be570e:g:hosAAOSwK~RaBQLn:rk:3:pf:1&frcectupt=true

Maybe someone else on here that has used one, might like to comment.

Cheers Banjo 

yeah I've seen those, I might have to resort to them. Or else scab around work and see what I can get.


Cheers fellas

What type of 5k? Mild, hot, boosted?

A mild 5k id go, 0.3mm on the top two rings(could run the second a touch tighter on a stock N/A) and oil ring rails 0.27-0.3mm. Never file the expander(zig zag ring)of a 3 piece oil ring it sets the tension. 

Usual rule of thumb is 4 thousandths of an inch per inch of bore diameter. Plus more for boosted engines.

Edited January 4, 20197 yr by kickn5k