performing the 2.6 gt mods on a block

[keefallan]

I have ported my 150 before. I had a friend help me with some information I acquired from him. It was just tedious. I liked it. There's another aspect of porting the motors that I haven't done. Has anyone cut the openings into the side of the cylinder and used the gt pistons(scalloped) in it? How much power does that add to just porting? What's the purpose of it...........breathing? I'm re-building(hopefully) a gt-150 motor this winter if you get my drift.

I'm gonna open up a can-o-worms here. BUt I would like to hear evryones opinions on pistons(stock, sierra, pro marine, vertex, and wiseco). I am not trying to offend anyone, I am just curious. I already know about glm pistons.

I love hearing people's experiences with products.

 

[emdsapmgr]

Re: performing the 2.6 gt mods on a block

You can't get the factory pistons anymore-NLA. I bought some replacement Bombardier big bore 235 pistons and had a machine shop cut the skirts to match the original factory pistons. They run just great. Likely your problem will be cutting them and the block. You really need the exact dimensions or a 2.6 block to work with. Same goes for the porting. Those 2.6's have oversize factory ports. You'll also have problems locating the exhaust filler blocks for the exhaust chest, then have them machined into place. (top of picture #1.) Remember, the 2.6 was a 160 cubic inch block, high ports. Your block is 149 cubic inches, and a low port block. You are looking at a lot of time and $ for the complete modification. Do you have the rubber intake filler blocks also? You may be best off to just make yours into a GT/XP 150 engine.

 

[Faztbullet]

Re: performing the 2.6 gt mods on a block

Has anyone cut the openings into the side of the cylinder and used the gt pistons(scalloped) in it?

Yep... get out the pocket book:joyous:

How much power does that add to just porting?

About 10-15 hp on top end but takes away some umph on low end so you need a light hull to put it on. If you could put a 2.6 "hump" on the block it would add more but parts just dont line up correctly for a bolt on addition.

BUt I would like to hear evryones opinions on pistons(stock, sierra, pro marine, vertex, and wiseco). I am not trying to offend anyone, I am just curious

The ProMarine,Red Rhino,Mallory,Redline, are all rebadged WSM pistons which I really like since Vertex are so hard to acquire . Serria's are good as some are made by Persan for them. Wiseco's are last on my list but good to run in a worn out hole due to excessive clearance.

 

[keefallan]

Re: performing the 2.6 gt mods on a block

Thanks Harley and Faztbullet for your input. I was doing all this asking because I wanted to see what venue to go with putting together this blown gt150 motor that I have acquired in the purchase of my new/old Ranger(new to me, but not so new). I restored the boat. The motor needs to be re-built. The oiling system on it I think failed. I was using the oil in the oil tank for another engine of mine and it had clumps of stuff in it!!! I don't have any other way of saying it! Need less to say, I haven't used it since. But thankfully it has only cost me an inline fuel filter.

So I think you guys have helped me to decide what I'll do. I'm going to get it punched out to whatever it needs and get it ported at the same time by them. When I did my last one it was very hard to get at the exhaust side. The intake was pretty easy. I'm also going to use the stock gt heads instead of trying to find the 872's or 456's. I have a set on my ported motor now if I want to swap....HHmmmmmm

Keith

 

[Faztbullet]

Re: performing the 2.6 gt mods on a block

If it was mine all I would do is match all the ports,(heights on intake & exhaust) Square off the intake side ports,slap on a set of 86 model 175 carbs and some decent heads. This will get ya about 165hp at prop and wont have to run hi test fuel..... Or slap it together, sell it and get a 175 60 degree

 

[emdsapmgr]

Re: performing the 2.6 gt mods on a block

Don't forget the rubber intake filler blocks. Worth 5-8 hp.

 

[keefallan]

Re: performing the 2.6 gt mods on a block

I'm going to look for a set ASAP, Harley.

Can someone explain what finger porting is? I've heard that many times. But I have never seen it or understand what is actually being opened up.

 

[Faztbullet]

Re: performing the 2.6 gt mods on a block

Finger porting is a slot cut into sleeve with a matching port in piston and is found on looper engines and does add power to them. On a crossflow they work a little different because of crossflow piston design and add little power.

 

[keefallan]

Re: performing the 2.6 gt mods on a block

One last question performance wise: what can be done to the reed cages(if anything) to help airflow? I see different shapes of reeds. What are the advantages/disadvantages of them?