Piston Rings

SammyBGTT

Member +
Hey everyone. So my car started to misfire the other day and after going through the usual checks we did a compression test and sure enough cylinder 3 was at 30. We suspect it’s probably just the piston rings that have shat themselves.

First off what size is the bore? I’m assuming 74mm but not everywhere is very clear.

secondly has anyone ever used Wossner rings as a set of OEM rings are hard to come by.
 

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SKINY

Lifer
Yea 74mm,
Obviously you won't know until the piston comes out but fingers crossed it is rings Bud :)
 
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Jay

Admin
Do a leakdown test before going any further. It should give you an indication where the leak is.

Suddenly losing compression like that could easily be a stuck valve so take the cam cover off, rotate the engine manually and make sure that all the valve buckets are moving properly. If one is sticking that's probably going to be an issue.
 

SammyBGTT

Member +
I'd also suggest that you determine why that issue occurred in the first place.
this should help to avoid it reoccurring in the future.
What do you think could be the cause? The head was rebuilt and “port and polished” by the previous owner so I don’t know if that could play a factor?
 

Jay

Admin
You lucky ducky o_O

I bent an exhaust one about 5 years ago and they were still available to order. Might be worth exploring that first before looking for a used one.
 

SammyBGTT

Member +
You lucky ducky o_O

I bent an exhaust one about 5 years ago and they were still available to order. Might be worth exploring that first before looking for a used one.
Jap service parts do exhaust valves but not many. Would like to replace all the valves and stem seals but finding the parts it proving quite hard.
 

Jay

Admin
I got mine through Toyota, had to wait a while on it from memory. If its had work before that could have something (or nothing) to do with it. Hard to tell over the Internet.
 
worse/practical case alternative is to check for a used head in good working condition and be on your merry way---this is if you can't get replacement valve(s) or your head is seriously damaged .
however, i'd strongly suggest that you consider refurbishing the used head to be safe, its easier to do this while the engine is apart (at minimum replace the valve stem seals and reseat the valves)
 

SammyBGTT

Member +
worse/practical case alternative is to check for a used head in good working condition and be on your merry way---this is if you can't get replacement valve(s) or your head is seriously damaged .
however, i'd strongly suggest that you consider refurbishing the used head to be safe, its easier to do this while the engine is apart (at minimum replace the valve stem seals and reseat the valves)
I’ve just been quoted £650 for a set of valves from Toyota . I’m thinking now my best option is to look for a new head or at least some decent second hand valves. I will be doing the stem seals and a reseat.
 

SammyBGTT

Member +
Is it just the one exhaust valve you need?
It is just the one exhaust valve that is broken. Japservice parts have some however they arnt genuine and if I’m going to put the head back on with confidence I wanna be replacing all the valves and stem seals and for them to be genuine. I’ve been quoted £500 pounds for Valves and Seals to be important from Japan by Torque GT so that’s what I’m going to be doing. Look after your valves people . They’re pricey
 
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