1979 85hp run it, rebuild it or trash it

[wayneo99]

motor ran good 3 yrs in a row. compression at end of summer was 90 on all 4 cylinders.
so i decided to fix lower unit and trim leak which i just completed.

pulled the heads to change the gaskets and BAM starboard side headand piston is all bashed up from broken ring. cylinder walls looked good no scoring. I pulled the side plate and can see any scoring on the piston either and ring is intact from what i can see.

three other pistons have std .015 stamped on them and bad cylinder has .20 stamped into it

could this have been running like this for the last 2-3 yrs?
it ran great smooth and even idled pretty good once warmed up.
compression was even but obviously not as reliable as I thought.


i have a 140 parts motor with 90 psi all around so i pilled the heads and found the one piston and head totally wrecked.

after 33 yrs it maybe time to put the old girl away for good.

any thoughts?

 

[coolbri70]

Re: 1979 85hp run it, rebuild it or trash it

i have that motor, i really like it, i would rebuild it, but thats me and my hobby/profession

 

[rothfm]

Re: 1979 85hp run it, rebuild it or trash it

yea, it all depends on your "level" of comittment to spending time/money on it. Some folks really like to do the work themselves saving money and the satisfaction of it all. Others just want it fixed asap and dont mind cost at all. Others dont want to deal with an old motor, and just want a newer one.

Depending where your at, will dictate the direction for sure. However, I'm in group 1 and like working on the older ones. That motor is a nice engine, and could be back in action with some attention. Parts are readily available, and once done would last another 20 yrs properly maintained.

I'd say go for it, and rework it.

 

[Chinewalker]

Re: 1979 85hp run it, rebuild it or trash it

It looks like you already have some oversize pistons onhand. If the 140 block is standard bore and some of the oversize pistons onhand are in PERFECT shape, then you might be able to use them when boring the 140 to oversize.

 

[wayneo99]

Re: 1979 85hp run it, rebuild it or trash it

i think im going to use the current running 85hp because it know it does runs pretty well actually.

since it has been rebuilt in the past and has 3 .015 newer pistons which show good compression i would like the experts thought on just replacing the blow cylinder which is already .020 over.

maybe just a hone and rings or .030 over and a new piston im not sure.
what is the best piston to use?

but dont want to sink to much cash into a 33yr old salt water motor.

definatley going to redo carbs as that may have caused the ring to break.

water diverters were in the right place and water passages look clean.

what do you guys think?

 

[phillnjack2]

Re: 1979 85hp run it, rebuild it or trash it

well is this piston giving trouble ?
is the ring broken on this piston or is it damage that was done previously and had a not so good
piston put in with new rings on it already ?
if the compression is up then its doubtfull that the ring is broken anyway.
are you sure it wasnt the end of a spark plug broken off !!!!!!!!
But if the bore is not scored and none of the other bores are scored niether, why not just replace the
one piston and put new rings on ALL pistons while its down.
You then just run the engine in like a new engine for a few hours and then the old girl will last a lot more years to come.
youve done the hard bit taking the heads off, you dont need to do much more and get at the big ends to let you
pull the pistons out of the block.
skim the head and hey presto you have a nice engine again for not much money.
the age is not a problem if the block is good, i know of many engines less than 5 years old that are total scrap.
My friend has a 1977 140 that has a very strong engine with 140 psi on every cylinder, now that is better than a
lot of much newer engines.
a good runner is a good runner, while spares are plenty, and its not too rusty then keep it .

plus have you seen how much a new engine of same power is nowdays !!!!!!!!!!!!!

im just about to hopefully rebuild a 1995 60hp, and that is already 17 years old...


phill...

 

[emdsapmgr]

Re: 1979 85hp run it, rebuild it or trash it

Normal compression on a "new" 1979 85 engine would be in the 125 lbs range, so the current 85 is in need of overhaul. Depending on the cyl wall taper, you may not need to overbore it from current. You will need one new replacement piston and 4 new ringsets. Be sure that you match the pistons-all need to be from the same manufacturer. Don't mix pistons from two suppliers in one engine. Here is the deal. the bore size, pistons and cranks are all the same between your two engines. The 140 will bolt to the midsection of the 85. Why not refresh the 140? For the same $, you gain 55 hp.

 

[1FASTLASER]

Re: 1979 85hp run it, rebuild it or trash it

Normal compression on a "new" 1979 85


engine would be in the 125 lbs range, so the current 85 is in need of overhaul. Depending on the cyl wall taper, you may not need to overbore it from current. You will need one new replacement piston and 4 new ringsets. Be sure that you match the pistons-all need to be from the same manufacturer. Don't mix pistons from two suppliers in one engine. Here is the deal. the bore size, pistons and cranks are all the same between your two engines. The 140 will bolt to the midsection of the 85. Why not refresh the 140? For the same $, you gain 55 hp.

+1... .....Definately would put my money into the 140 block....same money basically to build it as the 85 AND 55hp....kinda a no brainer to me.

 

[coolbri70]

Re: 1979 85hp run it, rebuild it or trash it

i would fix them both what is the hp rating on your transom? mine is 120hp so i would have to go with the 85hp however if yours is 140hp or over, then the 85hp might not enough anyway

 

[wayneo99]

Re: 1979 85hp run it, rebuild it or trash it

finally took all the parts of the 85 block, went back to the 140 which was a bear to remove from the midsection. i had to grind some bolt heads and chisel 2 nuts. basically i ruined the midsection but will be using the 85 mid section anyway.

now i have to decide if i want to trade in 2 cores and buy a reman long block or take it to a machine shop and do all the work myself.

here are a few pics to enjoy.

another question, the midsection of my 85 always had black exhaust/oil leaking down it i thought it was the carbs when tilted up. but looking at the midsection now i wonder if the gasket was leaking between the powerhead and midsection on the exhaust side. ????

 

[emdsapmgr]

Re: 1979 85hp run it, rebuild it or trash it

It is common for the V4 power head base gasket to fail, esp on older engines. Not only is it rather messy, but usually is accompanied by a secondary problem: exhaust gas/smoke will infiltrate the cowling and get re-ingested into the carbs. Not a fatal problem, but not good on a long-term basis. Now that you've gotten it apart you can address that gasket problem during reassembly.

 

[Faztbullet]

Re: 1979 85hp run it, rebuild it or trash it

Don't mix pistons from two suppliers in one engine.

Been doing this for 35+years and never heard this before can you explain????

 

[wayneo99]

Re: 1979 85hp run it, rebuild it or trash it

been looking at cost of internal parts to help me decide which way to go with rebuild by me or a reman powerhead.

so far it looks like a complete rebuild kit is about 700ish which included all gaskets, seals and bearings?
I have seen so kits with the needle beasing and some with caged bearings, any pros or cons to these besides assembly?
any specific brands to stay away from? I know sierra makes a kit and i see a few on ebay
thanks

as far as crank polishing goes is it neeeded or just bore the block and install new internals? one machine shop i talked to just bores or hones them.

 

[emdsapmgr]

Re: 1979 85hp run it, rebuild it or trash it

Suppliers use different methods to make pistons. Some are cast and some are forged. There can be weight differences between the two. Cast pistons flow/handle heat more evenly than forged. If using forged pistons, additional clearances may be required. It's easier if you stick to using all the same type pistons in an overhaul.

 

[Faztbullet]

Re: 1979 85hp run it, rebuild it or trash it

Suppliers use different methods to make pistons. Some are cast and some are forged.

This I knew but just misunderstood your posting of" suppliers", you can mix suppliers and materials as they should all weigh the same.. You can use OEM, Sierra, Vertex,RedLine,Red Rhino,WSM,GLM,Dolphin,DMI,ProMarine,Tech2O,Bottesi as they are cast and Wiseco and Wizard is forged. I myself do not mix cast and forged as expansion rates are different and can cause problems.

 

[chasin-tails]

Re: 1979 85hp run it, rebuild it or trash it

I just rebuilt my 115hp which is the same as both of yours. I bought my rebuild kit which was everything including pistons for $550 off ebay. I can't tell you the seller but would be worth looking into.

 

[chasin-tails]

Re: 1979 85hp run it, rebuild it or trash it

Also forgot but you will have to make sure you get the crossflow rebuild kit. They make crossflow, looper, and ficht. Our 70's motors even up into the 80's is crossflow. I looked back on ebay also and it is $599

 

[wayneo99]

Re: 1979 85hp run it, rebuild it or trash it

going to buy a reman powerhead by OBR via my marina. take a look at this motor cover

what year is it?
what is the gold color called?
the cover has a slant front but it fit on my 79-85hp and the pan of the evinrude 140 so it should work with the 83 140 powerhead right?

 

[1FASTLASER]

Re: 1979 85hp run it, rebuild it or trash it

If you dont mind me asking what r they going to charge you and what block are you getting?...an 85hp or 140hp block.? What do they claim to do to there remans?

 

[Faztbullet]

Re: 1979 85hp run it, rebuild it or trash it

going to buy a reman powerhead by OBR via my marina

Iboats also sells the OBR powerheads(Outboard Recycle) in case you want to compare pricing...

If you dont mind me asking what r they going to charge you and what block are you getting?...an 85hp or 140

The suggest list is $2376 on the 85hp and $2552 +200 core on the 140hp.(I have a account with them also)The powerheads come with 1 yr warranty and everything internal is new except block,crank,rods which are reconditioned. All machine work is top of the line and any factory modifications that came out over the years are applied if necessary.Warranty covers mechanical failures only, damage from fuel issues and faulty ignition components are not covered.