1985 4.3l v6 mercruiser piston rings

[kazek]

Hello. Can someone steer me in the right direction on sourcing std piston rings. I am in the rebuilding process and need rings for org pistons. Seems that I find right rings. Can someone share the part #. I have been researching auto sites and ordered the set, but radial with is not correct. Mine is .1875 (.188) but ones I can find have .146 width.
Ring 1 is one that I ordered E251K. Ring 2 is original

 

[Scott Danforth]

GM used mahle rings in 1985

 

[Scott Danforth]

Some light reading. https://forums.iboats.com/threads/complete-history-of-the-4-3-liter-with-casting-numbers.693935/

 

[kazek]

Hello. Can someone steer me in the right direction on sourcing std piston rings. I am in the rebuilding process and need rings for org pistons. Seems that I cant find right rings. Can someone share the part #. I have been researching auto sites and ordered the set, but radial width is not correct. Mine is .1875 (.188) but ones I can find have .146 width.

I have ordered E251K set but wrong radial width of the ring

 

[kazek]

40664CP from mahle seem next hit but there is no specs as to width of the rings

 

[Fun Times]

If you have it, need your engine serial number to confirm.

 

[Scott Danforth]

Remember, 1985 is a one year wonder.

If you're doing rings, you also need pistons and a bore/hone

 

[kazek]

Remember, 1985 is a one year wonder.

If you're doing rings, you also need pistons and a bore/hone

I did the hone. Keeping with old pistons...thus the set back. Can't find the rings

 

[kazek]

If you have it, need your engine serial number to confirm.

It's 10105867 no balance shaft

 

[Fun Times]

It's 10105867 no balance shaft

Was hoping for your Mercruiser OEM engine serial number that probably starts with 0A******....10105867 is the casting number.

 

[kazek]

Was hoping for your Mercruiser OEM engine serial number that probably starts with 0A******....10105867 is the casting number.

First digit is hard to read. Could be cast flaw but all digits

 

[Fun Times]

First digit is hard to read. Could be cast flaw but all digits

Sorry, possibly my mistake.

The number you gave was a engine block casting number and from searching that number out seems to indicate the engine you have was used in 1987... Your 1985 engine block "may" had been changed out at some point.

My first thought was to confirm the year of your original engine year by using Mercruiser serial number because sometimes while the boat is 1985, the engine might have been from 1984 or 1986 even.

1984 shows a different piston ring part number than a 1985 ring number... Using MerCruisers parts guide, figured I'd guide you to the OEM part number to make the search easier knowing what one you needed from new.

Your casting number may be telling a different story thus why you might be having trouble finding the right rings.

Scott Danforth put together a GM V6 guide that lists your casting number 10105867 under 1987.... Unfortunately I don't believe there is a list of V6 casting number chart online like they do with the V8 blocks that would tell you more info about what was used where, time wise.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

To add to Scott's guide above there is also the following info regarding GM V6, https://www.hotsixes.com/chevy-v6/3/

Just not sure if your year answer is in there yet.

If the Merc original serial number is still there, then just above the engine starter would be a metal tag riveted to the engine block with a number on it that looks like something in here,

Where to find Mercruier Stern Drive and Engine serial numbers.

Stern Drive serial numbers. (Continue down to the next posts for engine locations) ---------------------------------------------------------------------------------------------- All Mercury Marine serial numbers follow a particular format, be they Engine, Drive or Gimbal housing. Up to about...

forums.iboats.com

Or there could be a sticker on top of the covers that have/had the original serial number on it that you'd want to use to look up other parts of the engine to help get the other right things when needed such as outside bolt on accessories.

RE: PISTONS

Chevy 229,3.8, 262, 4.3, 4.3L, V6 Chevrolet engine and parts | Hot Sixes 6 Cylinder Engine Information the 6 cylinder encyclopedia - Part 5

chev v6 engine identification, fitting roller rockers to 4.3L chevrolet use Aussiespeed tall valve covers, chevy 229 american v6 high performance information - Part 5

www.hotsixes.com

 

[kazek]

Sorry, possibly my mistake.

The number you gave was a engine block casting number and from searching that number out seems to indicate the engine you have was used in 1987... Your 1985 engine block "may" had been changed out at some point.

My first thought was to confirm the year of your original engine year by using Mercruiser serial number because sometimes while the boat is 1985, the engine might have been from 1984 or 1986 even.

1984 shows a different piston ring part number than a 1985 ring number... Using MerCruisers parts guide, figured I'd guide you to the OEM part number to make the search easier knowing what one you needed from new.

Your casting number may be telling a different story thus why you might be having trouble finding the right rings.

Scott Danforth put together a GM V6 guide that lists your casting number 10105867 under 1987.... Unfortunately I don't believe there is a list of V6 casting number chart online like they do with the V8 blocks that would tell you more info about what was used where, time wise.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

To add to Scott's guide above there is also the following info regarding GM V6, https://www.hotsixes.com/chevy-v6/3/

Just not sure if your year answer is in there yet.

If the Merc original serial number is still there, then just above the engine starter would be a metal tag riveted to the engine block with a number on it that looks like something in here,

Where to find Mercruier Stern Drive and Engine serial numbers.

Stern Drive serial numbers. (Continue down to the next posts for engine locations) ---------------------------------------------------------------------------------------------- All Mercury Marine serial numbers follow a particular format, be they Engine, Drive or Gimbal housing. Up to about...

forums.iboats.com

Or there could be a sticker on top of the covers that have/had the original serial number on it that you'd want to use to look up other parts of the engine to help get the other right things when needed such as outside bolt on accessories.

RE: PISTONS

Chevy 229,3.8, 262, 4.3, 4.3L, V6 Chevrolet engine and parts | Hot Sixes 6 Cylinder Engine Information the 6 cylinder encyclopedia - Part 5

chev v6 engine identification, fitting roller rockers to 4.3L chevrolet use Aussiespeed tall valve covers, chevy 229 american v6 high performance information - Part 5

www.hotsixes.com

That makes more sense. Thank you Sir. There is no tag attached. It is possible that at one time engine was replaced. Just got 22 crestliner and history of the boat is unknown to me. Block's number is the one to be from 1987
Will follow this lead and check other years for proper rings.

 

[Scott Danforth]

measure the bores with a bore gauge. you will need more than just the rings unless the block was brand new sitting on a shelf in a time capsule. if it has any hours on it, the bores are no longer round and will be tapered. this means that you will require a minimum of a 0.010 oversized bore/piston/ring

1985 was first year of 4.3. it is the only 2-piece RMS block
1986 is a sort of one-year wonder as well, however being 1987, the pistons will be the same as any 1987-1992 4.3 V6s made in the Tonawonda engine plant (truck and industrial engines). the Romulus plant had a different mix of parts as those were car motors.

 

[kazek]

Thank you for reply. I did changed all bearings, polished journals. Tolerances are great. Also measured cyl with caliper in few spots. Seem fine.

 

[kazek]

Thank you for steering me to follow the block #. Came with 2M5712 hastings rings. Mahle 40664CP. I would love mahle, but delivery time is Jul 31 . Any thoughts on hastings rings?

 

[Scott06]

Thank you for steering me to follow the block #. Came with 2M5712 hastings rings. Mahle 40664CP. I would love mahle, but delivery time is Jul 31 . Any thoughts on hastings rings?

Hastings are fine for stock replacement .

 

[kazek]

Hi, just an update ...hastings 2M5712 came in. Top ring is 0.146 width. so no good. 2nd ring is good width. So back to square one. Didint bother with oil rings. Anyone know the part # for rings width .175"-.188" for 4" standard piston? 4.3 engine?
PS.:I am ordering parts from reputable auto site ( same block and internals).

 

[tank1949]

Hello. Can someone steer me in the right direction on sourcing std piston rings. I am in the rebuilding process and need rings for org pistons. Seems that I find right rings. Can someone share the part #. I have been researching auto sites and ordered the set, but radial with is not correct. Mine is .1875 (.188) but ones I can find have .146 width.
Ring 1 is one that I ordered E251K. Ring 2 is original

Go to auto-machine shop with part. They should be able to sell you correct one. You will most likely need to hone cylinder and remove wear ridge too.