Building/ freshening up my 175 big bore crossflow

[keefallan]

Mrichartz, I watched a video on the time-sert......awesome stuff. I had never heard of them. Been using heli-coils for years........done with them.

[racer]

Unless you are porting this engine to make power at 7000 IMO leave all the bridges in the reed block and just clean them up. They will last much longer and flow plenty of air. I have tried more different intake variations than I want to think about, most are a very little help compared to cleaning up stock, a couple did help above 4000 but these were on engines that would turn 8000 RPM and were ported for that. Anything over 6300 hurts reliability a lot and you need to stay away from 64 to 6600. Remember turning an RPM and actually making power at that RPM can be 2 different things. IMO I would not reuse rings, hone and go with new so engine breaks in correctly.

If you want to build a hot rod for a light boat (modified beyond just clean up these engine do not like pushing weight on todays fuel) search on here for OMC 9 pages. It lists what to do but for an everyday application IMO change the port radius to 5/8 or 3/4. Later testing found going under 3/8 only hurt life without any additional power.

[keefallan]

Alan, thanks for explaining things about the reeds and the intake questions. As for the rings.........I had already come to that conclusion earlier today when I had my hands in the bores. Truth-be-told, I realized I didn't want 30 year old pistons in there after seeing the scuffing on that one piston. It didn't make sense to me to install a brand new one and the others are very old............even if compression was great and the cylinders are in good shape. SO, I think I am due to get a set of new pistons(rings too) for the engine.

[keefallan]

I got a few good things checked off my list today. will bring 'em up when I can take pics tomorrow and talk about it then.

I will talk about this one though. I got the reed cages all reworked and lapped. I will take pictures of that and post it. I did end up cutting out the 1st and 3rd cage fingers. Let me explain.

After reading Racer's post, I thought about it. He's right about the reed cages. I was too blinded by wanting more airflow. The 2.6 xp had fiberglass reeds with stock cages..........and it pulled to 6000 plus. SO, in the future, when I do this again, I will use the stock style reeds. I am sure I will do this again, because I have a 150 block, another big bore block, a v4 block and a v4 motor. All of them need boring. I will only buy the factory correct reeds from Chris Carson. I have used his reeds for 3 of my motors now. I love them. He's also a really cool guy to talk to. He bored out my 235 a few years back. He's got my business.

Back to the reeds......so since I had already purchased the reeds AND cut a cage already, I just finished it out. I wasn't going to send the reeds back, throw a cage away and start over(but that is only reason). Those high flowing cages aren't gonna hurt me. It may shorten the lifespan of the cages. I have some spares in a box. But I doubt that I will do it again. They do look nice and they are blended as much as I could. I tapered the entry openings and smoothed out all sharp edges and was very tedious at the nose of the cages to make sure they were smoothed since the air runs past/over that lip.

I looked at the block again while showing it to a friend today. I am gonna port the center ports of every cylinder. I am going to go left-right only with the porting. I am not moving the exhaust port any. I am just going to square them up some in the center ports. I am leaving the edge ports alone. The fangs are coming out the ports also. I am going to stop there. I am not doing any scalloping. But there is a large ridge at the bottom of the cylinder in the intake tract(right where the scalloping would be). I will be removing that ridge entirely to open up the intake more........I will call it unnecessary aluminum. I have soooooooo much clean up to do in the manifold and the intake tract. I would like to have seen how much hp a 150 would have made with just optimizing airflow both in and out of the engine. I know air hates sharp edges...........and the those aforementioned things are full of them. There is definitely some power to be had in this.

[FMP]

3121?
http://www.wiseco.com/ProductDetail....989&AppID=9840

And some decent compression!

[FMP]

How about a bit of funnelling shape on the ex ports sharp edge to the chest. I did a bunch of shaping and area stuffing with aluminum ceramic on a xflow, not OMC. It's definitely helping the signal and dead areas to help the out and in of things. Just a thought for you.

[keefallan]

How about a bit of funnelling shape on the ex ports sharp edge to the chest. I did a bunch of shaping and area stuffing with aluminum ceramic on a xflow, not OMC. It's definitely helping the signal and dead areas to help the out and in of things. Just a thought for you.

Do you have a pic to show what you are saying? I haven't even brought this up yet, but I do want to work on a couple of spots in the exhaust areas in the filler blocks. Cylinders 2 and 3 get the leftovers in exhaust area, and I want to open them up some, but I don't want to ruin the fillers because they aren't available any more........or if they are............stupid expensive.

[keefallan]

3121?
http://www.wiseco.com/ProductDetail....989&AppID=9840

And some decent compression!

not sure the direction I'm going yet............but I do like their compression............they made 15-20 more lbs in my v4 than the stock pistons. With tight heads I was seeing 160 with off the shelf parts.......had to run really good gas tho....

[FMP]

The motor I did that to had individual compartments for each cylinder at the ex ports. The corners took the stuffing and some port blending to shape.
The area around the ports on the OMC , the corners around the perimeter of the port area , can't really make the contour out in the pics but looks like some dead areas in spots. It's not just flow but what the pressure signals do in those spots and how they can be made to follow shape to and from the port.
I'm sure someone has tried shaping etc.

[FMP]

Just after milling ports but you notice the outside corners etc , dead areas that took stuffing and blending after surface preparation. Ports were then blended. Individual compartments per cylinder which then has stuffers installed to further transition smooth to the"primaries" of the manifold system.

[keefallan]

Thanks for the pics.........gives me ideas with mine for blending.........specifically cylinders 3 and 4.

[keefallan]

Reed cages:

[keefallan]

Here's my working on a piece that needed a lot of blending down. Definite improvements in airflow on this one!!



This is how it should've come from the factory. I know its cast..........but make this mold and cast it!! Check out the hard square corners in the stock piece. Its over 1/4" of useless material. It reminded me of porting cylinder heads. You flip it over...and you see another angle to blend down or in.

Keith

[FMP]

I worked the block, adapter to tuner as well. A curve needed work , a drop off 90° that caused lots of short side flow eddies before the tuner to name one.

[keefallan]

Ok here's what I was able to work on since I haven't been able to move forward with the block yet. I spoke with my friend on the phone about the block, and I will be working on that very soon. So in the first set I have the velocity stacks b4 and after.