Next project - 115 and then some!

[Chinewalker]

Late last winter I rebuilt a 1984 Johnson 90 for a Starcraft 18 American that is (still) getting redone. It should be a nice set-up, but I somehow think it won't quite get to the "thrilling" fast plateau. Sooo......

A couple weeks ago I went to an auction at a local marina that had changes hands. The new owners were clearing house and I managed to pick up a small pile of V4s in various stages of disrepair.

Now for the question - Two of the powerheads were still attached to mid-sections and had serial tags to look up - appeared to be 88SPLs (flat back exhaust). The third powerhead looks like a rebuilt or replacement, as it was not on a towerhousing and the freeze plug just had a number, no model. BUT, it does have a bubble back and the carbs on it. How do I go about determining what powerhead it is? Looks like it has VRO and the block is painted black, making it mid 1980s or newer.

The plan now is to rig up the Starcraft with the 90 for now and rebuild the bubble back for next season. Gotta get the 18-footer to dance like its 15-foot brother with the Stinger 75.... I'll be scanning the archives here to make sure I get the "right" parts when the time comes.

Thanks!
- Scott

 

[Dhadley]

Re: Next project - 115 and then some!

On the block with the bubble back, take a by-pass cover off and send me a pic. dhadley50@aol.com

Since it has the good exhaust we'll assume, for the moment anyway, it has the good port timing but I can tell from a good shot of the intake ports.

 

[Chinewalker]

Re: Next project - 115 and then some!

UPDATE: Well, I finally lugged the V4 powerheads down to the shop this weekend and tore into them. I think I confirmed that the bubble-back block is indeed a 140! With the 88SPL block and the 140 block side by each, the intake and exhaust ports on the 140 block are considerably larger! Whoohoo!

I did discover that the exhaust filler blocks were broken up. There was a large chunk missing and the other one was broken, so I'll need to track down a pair of those.

I did discover that the block was standard bore across the board, and only one bore had any real damage. The other three are a tad on the loose side, so it'll get .030 oversize across the board.

Speaking of which, I got one good .030 piston out of the 88SPL powerhead. BONUS!! Not sure what happened to that powerhead, as it looked like one of the rods had the bolts loosen up. The rollers and cages had both slid to the same side and been more or less welded together. Toasted the crank and the crankcase in the process. More scrap metal for the pile, I guess.

I'm going to get into the second 88SPL powerhead today and hopefully I'll find another oversize piston or two!

- Scott

 

[Dhadley]

Re: Next project - 115 and then some!

Forget about finding the exhaust filler blocks. You don't need the inserts. Use the "bubble back" exhaust without them.

Are you sure you don't want to go to .020 rather than .030 right off the bat?

There's a ton of untapped power in the intake side of a V4 crossflow.

Walleyehed, are you there?

 

[Chinewalker]

Re: Next project - 115 and then some!

Hi Dhadley,

I do have three .020 oversize pistons here that I took out of the other 88SPL yesterday. They look pretty good and aren't chewed up. They are not OMC pistons, though, and I'm not sure who made them. I'd need a fourth of the same to do what I want to do. They have a logo cast into the inside of the skirt "Persan" and the number 354. In all, I've got three .030 OS pistons (OEM), and three .020 OS pistons (aftermarket). Aren't most aftermarket pistons forged instead of cast? I thought I had read here somewhere that mixing and matching can cause problems...

I'd like to keep all four matching, if possible. I've got a local Johnrude dealer that I get along well with, so I'd like to go OEM to support them if possible. They'll be handling the boring and I'll be getting the gaskets, carb kits, etc. from them, though, so if .020 is the way to go, and I can find one to complete the set, it's not a huge deal, just a preference...

On a side note, one of the cranks I've got has a couple of tiny (pin-head sized) imperfections in the bearing areas - one on the center main, and one on the top rod journal. Are those a problem, or will they hold a bit of oil for the bearings? I don't think the bearings shouldn't have any trouble bridging the spots.

I've got several intake manifolds, so it's not a problem for me to experiment with one. And thanks for the info on the filler blocks...

- Scott

 

[Chinewalker]

Re: Next project - 115 and then some!

I just did a Google search on the Persan name, and it looks like the .020 OS pistons are Sierras. Are they cast or forged?

Thanks,
- Scott

 

[Dhadley]

Re: Next project - 115 and then some!

They're cast.

 

[Dhadley]

Re: Next project - 115 and then some!

Those pin sized holes are imperfections in the metal. They've probably been there since new. I wouldn't worry about it. Send me a pic if you're concerned. dhadley50@aol.com

 

[Chinewalker]

Re: Next project - 115 and then some!

Thanks Dhadley!
- Scott

 

[Dhadley]

Re: Next project - 115 and then some!

What kind of rpm do you think you'll be looking for?