Looper exhaust porting

[FMP]

What was it prior, can you accurately measure the width of the ring around it to see if it thinned the one side? .027 with a hone and fresh rings may stay the same or get a bit tighter if the ring has thinned.

[Captain75]

What was it prior, can you accurately measure the width of the ring around it to see if it thinned the one side? .027 with a hone and fresh rings may stay the same or get a bit tighter if the ring has thinned.

I’ve checked, the ring width/thickness is the same on all sides.
I’m thinking perhaps I should use cast pistons instead!?
I have a set if OEM in good shape with all new riken rings. The riken rings are a bit tricker and seems to have a bit more tension than the wiseco rings.

[FMP]

Lots of good work to leave behind. With the bores still very near std size and you have honed them once, seems as if the gap is intentional. How much difference in gap after running , 0.003-4? Wiseco dimension, width # if you could compare would tell something. If the ring width is exactly the same around the ring, particularly the transfer scuffing side I'd first rehone then fit the used ring again for gap and subtract the amount it increased during the hrs running and consider a second attempt with fresh rings, with an even longer heat cycling schedule and longer warm ups. Also try and fit the larger gap ring on top, this means fitting each set of rings in each bore as a final. So if you want, one bore at the same depth to measure all the rings keeping track of each and using them to fit the difference in bore sizes. Likely all the rings are exactly the same so this may just be insurance.
Or those OEMs, they're also forged?

[Captain75]

Lots of good work to leave behind. With the bores still very near std size and you have honed them once, seems as if the gap is intentional. How much difference in gap after running , 0.003-4? Wiseco dimension, width # if you could compare would tell something. If the ring width is exactly the same around the ring, particularly the transfer scuffing side I'd first rehone then fit the used ring again for gap and subtract the amount it increased during the hrs running and consider a second attempt with fresh rings, with an even longer heat cycling schedule and longer warm ups. Also try and fit the larger gap ring on top, this means fitting each set of rings in each bore as a final. So if you want, one bore at the same depth to measure all the rings keeping track of each and using them to fit the difference in bore sizes. Likely all the rings are exactly the same so this may just be insurance.
Or those OEMs, they're also forged?

Tnx for your replies! I will have them in mind.
The other pistons are cast.

[racer]

2 bores smaller than stock on a used engine that was then ported rehoned and run again? IMO not very likely and I would remeasure. IMO to run a wiseco piston bores need to be 3.6865 to 3.687

[FMP]

Have to assume gauge calibrated correctly

[Captain75]

2 bores smaller than stock on a used engine that was then ported rehoned and run again? IMO not very likely and I would remeasure. IMO to run a wiseco piston bores need to be 3.6865 to 3.687

Racer! As others I always appreciate your relplies!
Whats your opinion of how big bores (over 3.685) can I use before I need to have them bored to next over dimension. If they are round of course!
with wisecos?
with cast?

[Instigator]

I’ve done a lot w/worn bores but fuzzy on numbers.

I went so far as to use over bore/size rings on standard bore pistons by filing end gaps.

What I do remember is getting compression where it should be but motors were always down on power and wore quickly.
Most if those bores were egg shaped too.

Round and straight is fast!

Racer! As others I always appreciate your relplies!
Whats your opinion of how big bores (over 3.685) can I use before I need to have them bored to next over dimension. If they are round of course!
with wisecos?
with cast?

[baja200merk]

On stock stuff (e-tec) I don’t give the wisecos any extra clearance. From what I understand Unlike the earlier series they build clearance into the piston and use an alloy that doesn’t expand as much/fast. I’ve taken motors with under an hour on them to the lake and run them up to 5800 (after warmup of course) with no clearance issues. The DI stuff has very high cyl temp too on edge all the time. All the 4-stroke rebuilders around here like them also so I think they figured out how to shake the siezco name

Mine turns 7k+ So it got .0015-.002 extra clearance.

[Captain75]

Fortunately, I have plenty of time to remeasure and decide what to do with the bores...

[Captain75]

I will leave the bores for a short while and look a bit further into the below topic. I will get back to the bores when I have access to another bore gauge as reference. Right now (after remeasuring) it seems only one bore is big enough according to the bore size tips I got from racer in a previous post. This fact together with old thermos might?? Explain the cylinder wear!?
Attachment 424127
Attachment 424128
All reliefs have been threaded and the question is what to use iot make sure the small bolts stay in place. My concern is their ability to vibrate and climb along the threads until it reaches the bore surface -boom... The ability to move further into the exh is prevented because the threads doesn’t go all the way through the relief hole.
How should this be secured/prevented? Loctite?

[Captain75]

Hey guys, I need some help to decide what to do with my bores!I have searched the net for some figures that can tell me go or no-go, but haven´t had any luck.


Today I tried to true up the bores using my rigid hone, some rather coarse stones and diesel.
Afterwards I tried to get some accurate numbers using the Bore gauge. The caliper used to set the Bore gauge has been checked with my neighbors quality caliper as reference.


The measurements listed below has been taken as follows:
Two different heights; 1 inch below the deck, and just under the exhaust port. On each height the Bore has been measured both horisontally (parallell to the rodslot) and vertically (90deg from rodslot)
All values refers to the stock bore size: 3.685” (93,599mm)


Cyl #1: 1inch below deck horisontally: + 0.0004” (0,01mm)
vertically: + 0.0004”
Below exhaust horisontally + 0.00098” (0,025mm)
vertically + 0.00098”


Cyl #2: 1inch below deck horisontally + 0.00078” (0,02 mm)
vertically +/- 0
Below exhaust horisontally + 0.00118” (0,03mm)
vertically +/- 0


Cyl #3: 1 inch below deck horisontally + 0.00098”
vertically. + 0.00078”
Below exhaust horisontally. + 0.00118”
vertically + 0.0004”


Cyl #4: 1 inch below deck horisontally + 0.0004”
vertically - 0.0004”
Below exhaust horisontally + 0.00059” (0,015mm)
vertically - 0.0004”


Cyl #5: 1 inch below deck horisontally + 0.00078”
vertically +/- 0
Below exhaust horisontally + 0.00078”
vertically - 0.0004”


Cyl #6: 1 inch below deck horisontally + 0.00236” (0,06mm)
vertically + 0.00118” (0,03mm)
Below exhaust horisontally + 0.0035” (0,09mm)
vertically + 0.00236” (0.06mm)


It seems to me my bores must have started on the tight end of 3.685...
The figures above seems pretty small to me, maybe apart from #6!?
Despite the figures, the pistons seem loose in the bore, at least from my very limited experience.

Any ideas or pointers?



The homemade spring assisted honing device

[Captain75]

Still tryin to decide how to do with my bores. Seems they have been a bit to tight for the wisecos.
A the mean time I’m doing some other mods such as drystacking the exhaust.
I’m considering to toss the exh liner iot gain accessable volume on take off. As you can see in the pic, the volume would a lot larger.
Any downsides to consider?


The other thing on my mind is the size of the cooling outlet nipples.

What would be the correct size iot not cause too high water pressure?

[phillnjack]

losing the exhaust liner can mean your going to need a different water pump housing due to it getting cooked by exhaust. by removing this you lose a bit of weight but cant see any other benefit. if putting a snout on then might as well lose it.

[rude tim]

losing the exhaust liner can mean your going to need a different water pump housing due to it getting cooked by exhaust. by removing this you lose a bit of weight but cant see any other benefit. if putting a snout on then might as well lose it.

I ran with no can and the water pump is fine even with a 16” Taylor mid. The pump will look like crap but it is hard to melt something that has water running through it.