85 to 140 Mod

[spybot]

85 to 140ish Transformation do i have all the parts ???

 

[flyingscott]

The block or have someone do the porting work.

 

[spybot]

The only porting work will be to square of the ports i dont want to lose any reliability.
This motor will be a fast loch boat something that i can go and have no issues with starting every couple of weeks.
What would you do to the block ???

 

[jimmbo]

What year is the 85?
If the 85 is the correct yr, the block must have the ports machined to 115/140 specs. If not done, you will just have a mismatch of parts that will have a weaker hole shot than before and erratic midrange, with little or no top end improvement.
Where in the world did you hear that the loss of the top piston ring is of no concern?
Why waste money on 'balancing the con rods and pistons'? Scalloping the pistons and cylinders?
You still need the exhaust tuner for the 140.
A much easier, often cheaper, and in most cases the only way, is to just remove the 85hp and replace it with a 140(crank rated) or a prop rated 110/112/115hp

 

[spybot]

I understand about the bridge work i said that in my post. The engine is a 1980 85HP J85TLCSA the ports are the same as the 140 or will be when the porting is done.
Regarding the tuner. the only V4 with a Tuner exhaust was the 1978 model and they are rare in the US so even harder to get here.
One thing i need to make clear is that i am in Scotland so there is not an abundance of Johnson spare to be had cheaply.
The carbs kits and reeds i had to order from the USA.
If you are referring to the bubble back i have this and the filler (which again were very hard to find on this side)
I will have the bottom rib removed and the filler plates machined flat.
All the question i have asked regarding the build have been asked in several ways
Each time i get a diffrent answer so i just collate them all and make my judgement from there on.
I am new to outboards plus i am working on an engine built in the US so the more i ask the better understanding i have

 

[jimmbo]

You are contradicting yourself, first you say you are not having the block ported, now you say the 85hp block has the same porting, or will have when the porting is done.
The 140 has always had an exhaust tuner/megaphone.

 

[flyingscott]

The ports are very different between those 2 blocks. I am curious how will you lose reliability by porting since the 115/140 blocks were very reliable motors. The only time reliability is lost is on bad porting jobs. A well done porting job to factory specs will not decrease reliability.

 

[interalian]

No Title

Here's a comparison of port sizes for 90 and 140hp. Intake ports are far larger but appear to be on the same center for each. You can see through to the exhaust ports and see they're larger too, based on the width of the rib between the cutouts.

When I did my 90-140 conversion, I researched and found the exhaust tuner was the same BRP part number for each, but my 90 was a 1982 and the 140 donor was a 1979.

 

[jimmbo]

BRPs parts catalogs are full of errors on the older engines.(I've seen where there was no difference part #s for the cylinder heads between a 90 and a 140) Maybe they were reducing/compressing inventories. Maybe that's where skybot got the idea the 85 and 140 blocks were the same. But the crank rated 140 has always had an exhaust tuner/megaphone(the 77 140 was reputed to have the best one, good for 1/2 mph on a LIGHT hull) while the lower hp didn't.

 

[interalian]

No Title

When I had the motors in bits, I could tell the exhaust megaphone was the same in each though. Pic one was what I had on each. Pic two is the much vaunted '77 tuna setup (that I wish I had, I guess).

 

[spybot]

OK gents i appear to have it all wrong regarding the ports. as i said i am asking as i dont know.
The porting will be getting done to 140 spec.be good if someone had the sizes, but i think i can get approximate sizes from the pics ( thank you Interalian )
The tuner pipe would be good but i will have to get some dimensions if i go down the road of fabing one up.
I only want a reliable l lake boat. With the help of you guys i think i can build it. If i get things wrong please point them out to me.
Jimbo iam lost on the tuner/megaphone I thought the 140 only had the bubble back exhaust i didnt realise the rest of the exhaust was tuned as well.
This is all good i am learning new things
So should i look out for a 140 mid/lower exhaust ??????

 

[interalian]

The picture was from V153, I can't take credit. If you want a full resolution version, PM your email address and I'll send it over.

 

[spybot]

Interailian PM sent
Thanks

 

[Faztbullet]

If you do not open up and raise the intake/exhaust ports you will still have a 85 but a crappy running one. Squaring the ports does nothing for the height as all your doing is smoothing the flows. Scalloping the pistons and block are race mod's and not for recreational use. You keep asking questions but wont accept any advice...even the guys over on S&F told you the same thing and you wont take their advice either. The time/effort/machining/parts purchased and selling your existing motor you could have likely bought a higher HP motor and bolted on and been done.

 

[spybot]

My 85 to 140 mod is in the beginning but i have put a dead line on it.
I must have the engine stripped and rebuilt by the 1st of Feb.
I want to turn my 1980 Johnson 85 into a 140 but a decent 140.
I know i have machining to get done (bottom rib removed, ports widened to 140 and block milled for filler plates) I also need two cylinders to be re bored to 2nd over size.
Now i have this work to be done on a budget. Its a real tight budget.
I have all the parts to make the mod, High comp heads 1 5/16th carbs, intake and exhaust stuffers.
I have purchased a job lot of wise pistons so will be using these, Santa brought me a set of Carson reeds.

First things to get done are the carbs
I have to remove the choke plates a they will be choke primer.
Once the choke plates are removed there is a sort of small shelf for the sake of a better word that is just behind where the choke plate spindle is.I had to grind that down and flush with the throttle bodies sides.
The holes which were left from the choke spindle i filled these with JB weld both inside and out. Then sanded down.
I then port matched the carb to the intake manifold.
One done to give you an idea of what they will be like before and after.
The motor i want to build is for play more than race so 6500rpm will be my goal.
Already port flowed the intake and the carbs. I will port match/flow every part of the build. The rods and pistons will be balanced.

What else can i do to help the engine stay strong at 6500rpm ?
The boat is a sidewinder copy at 16ft and 660lbs
Guys i dont have a shed load of money to dump im to this, in fact i had to save all year for the parts i have.
Plus i stay in Bonnie Scotland so there are not many spares to be had.
Any and all help welcome
Cheers Andy

 

[jbcurt00]

New topic merged w old.

please dont start multiple topics about the same subject