Crossflow build

**powerabout** · 09-18-2019, 07:13 PM

Hi Freddie how do your modded reed blocks compare with ficht 60 degree ones?

**Freddie Webb** · 09-18-2019, 07:46 PM

I should be at the shop tomorrow I will try and get you pictures of the reed block I sent to Chris.

**ssv170** · 09-27-2019, 01:01 PM

Curious, what block would be better to mod? Early small bearing or late model big bearing. Longevity not being an issue.

TIA

**Fastbass88** · 10-22-2019, 04:12 PM

Thanks for the help Freddie. I picked up some boyesen reeds and intake stuffers as well. Does porting the reed blocks pay off for the work involved?

Tore open the 135 bubble back, exhaust blocks not warped which is good. I'll machine the assembly a bit the match the porting and get as close to the size of a 140 bubble back as possible. The 135 has higher ports then the 88 so I'll copy them to the 88 and open em up some.

Can I swap the stator and regulator to the 88? Found out the 135 is a silver star flight with 12amp charging system. If it's all apart might be worth it over the 6amp on the 88.

I put a 23p prop on and got 47mph GPS with stock 88 (15gal fuel and 2 people). Hoping I can exceed that baseline with a large margin.

**Fastbass88** · 10-22-2019, 11:07 PM

One other thing although will be done at the end, I'm assuming timing is around 28bdc on the 88 currently. With everything ported and 76 135 heads, I'm seeing I should set timing at 22 deg at 4800rpm? Will be running 93oct and 32-40:1 oil.

From my research the 73 heads should run some av/race gas mixed in but 76 are safe enough to run on fresh premium with no ethanol.

**powerabout** · 10-23-2019, 04:53 AM

Perhaps someone has the bulletin on how to run a 135 on 80"s gas

**Fastbass88** · 06-10-2020, 09:13 PM

So this winter didn't pan out so great time wise, ended up not touching the 88. Decarbbed it this spring and worked to good plugging a bunch of things.

One plug is heli coiled on 88 and letting go, also gasket needs replacing on flat exhaust cover. So going to put 135 heads on and bubble back exhaust minus the stuffers for now.

My concern is the head gasket didn't seal enough on cyl 4 or there was some water intrusion. Ended up scoring some on the head mating surface

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How many thou can I shave them? I know 73 heads are the tightest, these 76 heads not far behind. Will be running fresh non ethanol 91 for sure.

**Fastbass88** · 06-11-2020, 11:21 PM

Also found the 88 block is stamped 90 and the 135 11. So the 88 is definitely a low/small port block. I'll rectify that when the season is over.

**perfmarine1** · 06-12-2020, 01:26 PM

Originally Posted by Fastbass88

So this winter didn't pan out so great time wise, ended up not touching the 88. Decarbbed it this spring and worked to good plugging a bunch of things.

One plug is heli coiled on 88 and letting go, also gasket needs replacing on flat exhaust cover. So going to put 135 heads on and bubble back exhaust minus the stuffers for now.

My concern is the head gasket didn't seal enough on cyl 4 or there was some water intrusion. Ended up scoring some on the head mating surface

How many thou can I shave them? I know 73 heads are the tightest, these 76 heads not far behind. Will be running fresh non ethanol 91 for sure.

Take that down by hand. Get a piece of bullet proof glass from a bank installation co. 3'x3' is ideal from the drive through.They tear them out all the time when remodeling a bank. They are laminated with 5 -1/4" pieces of glass, Or a real thick piece of glass and go to a abrasive co. or a floor sanding co. and get a piece of 120 grit sand paper or screen paper 2'x2'or 1'x2' and duct tape it to the glass, and sand that down moving it back and forth the long way and finish in a figure 8 motion,no side to side that will roll it. You will know when it is flat by looking at it and no chance of going to far,you should do this with all cases on a crossflow including the block.and reed blocks. The only surface you don't surface is the 2 surface's between the crank

**FMP** · 06-12-2020, 01:57 PM

Do both heads.

**Fastbass88** · 06-12-2020, 10:34 PM

Thanks for the input, had seen that done before on small engines. Cheap to try for sure. And I would try to get both heads close to the same. Biggest issue was thinking of a medium flat/true that was big enough.

Would I have to turn timing down to 20deg like the original 135 with the tight heads on the 88? Had seen in my manual the 140 xflows were 28deg exactly like the 88 is currently. Was planning on backing down if I don't find any info on it and tuning from there.

**Fastbass88** · 06-14-2020, 12:27 PM

Sanded heads flat and removed the gouges, took couple hours but surprising how quick I did it. Measured before and both heads were a couple thou out from flush, each were recessed in the middle of the head between the cylinders. Not sure if that was a factory tolerance or not.

**Fastbass88** · 06-28-2020, 07:34 PM

Found some interesting info on brp parts fiche. The 88 block is also used for the 110 of the same year. 110 has 1 5/16 carbs, bubble back, and maybe slightly different heads. My engine will have that now but with the 135 heads, intake stuffers and boyesen reeds. Hopefully have at least 110 prop hp if not closer to 125. Added fuel nipples to 135 carbs for solenoid system and rigged brackets to hold coil packs on the head. Almost ready for the water. Will retard timing to 20deg to get a baseline since I cannot find any info on timing with the head swap. 140 xflows were 28deg so thinking ill be back around there when finalized. I'll likely port it over winter unless it spins the 23 prop then I may leave it.

Continuing this thread to help others if they want to do the same. Not a ton of info on this for outboard newbies.

**powerabout** · 06-28-2020, 08:23 PM

Originally Posted by Fastbass88

Found some interesting info on brp parts fiche. The 88 block is also used for the 110 of the same year. 110 has 1 5/16 carbs, bubble back, and maybe slightly different heads. My engine will have that now but with the 135 heads, intake stuffers and boyesen reeds. Hopefully have at least 110 prop hp if not closer to 125. Added fuel nipples to 135 carbs for solenoid system and rigged brackets to hold coil packs on the head. Almost ready for the water. Will retard timing to 20deg to get a baseline since I cannot find any info on timing with the head swap. 140 xflows were 28deg so thinking ill be back around there when finalized. I'll likely port it over winter unless it spins the 23 prop then I may leave it.

Continuing this thread to help others if they want to do the same. Not a ton of info on this for outboard newbies.

how much comp does it have at cranking and what fuel do you intend to run?
original 135's could be around 150psi+ pretty easily

**Fastbass88** · 06-28-2020, 08:39 PM

stock with bathtub heads was 125lbs I'm thinking it'll be 150ish but need to install exhaust before I torque down heads which will be later this week. Running 93, maybe 95 oct for the first tank. Would like to use 91 but will see.