2.0L build

[LakeFever]

This winters project is to set up a 2.0L I have with as much performance as possible on pre mix pump gas so I am going to list out the mods I have planned, and welcome ANY input that will help improve power. I have a strong running 135 2.0L as a base and a hurt XR2 150 black max to harvest parts from. Planned mod list so far:

1. delete oil inj, pre mix 30:1
2. solid mounts
3. lightweight race cowl
4. XR2 exhaust divider
5. XR2 carbs, WH-29
6. Horizontal reeds
7. Chris Carlson reed spacers + new reeds, lapped blocks
8. mill heads 28cc ( too much? )
9. XR2 tuner, cut down 4" ( some rot on the end )

Thats about where Im at so far. I was thinking about the stronger rod bolts as part of this plan but wasn't sure the limits of the stock rod/bolts from 88? Is there anything I need to think about regarding the mid plate and swapping on the 2.5L offshore lightweight cowl? I was also wondering about jet sizes? Any worthy gains with porting anything? Port clean up worth it?

Please critique and add any suggestions or warnings you can offer. New to Mercs, but having loads of fun with this thing so far and very keen to learn more :D

[FMP]

Back a little while on a lengthy discussion regarding high duration porting etc the carbed ss120 was brought up. Porting specs etc, maybe that'll be posted again or linked.
https://www.screamandfly.com/showthread.php?228890-Merc-2-0-mods&&
Link within a link
https://www.screamandfly.com/showthread.php?227851-Capt-Insane-o-need-your-opinioin!!!!&highlight=captain+need
Loads of info

[Capt.Insane-o]

Port it to 120 specs, wh 46 carbs 26 cc heads and a 200 tuner.

[LakeFever]

That is awesome info thanks. I'm thinking of modding the 135 as mentioned, because I have almost all those parts in hand already and then take the XR2 I have and build that one to the 120 spec for the following year perhaps? Some of those RPM claims are insane! I was kind of aiming for 7000ish RPM thinking that was screaming but I am now eyes wide open there is a LOT more to be had on max effort. I hope to see somewhere around 80mph out of what im planning above. I'd be happy with 75, but bummed with high 60's

[fyremanbil]

I have ported a few to an "in between" level and had good results circle racing against guys running SST 120 engines. I think the port timing on the SST 120 may be just a little too high for non-tunnel boats for anything but top speed.

[LakeFever]

This is a lake boat, Hydrostream Valero for pleasure fun use only I dont want it to be an unreliable fuss monster nor do I want it to lose all bottom end entirely. I'm looking to make this thing rip as good as I can with good overall driveable behavior on 91 oct pump fuel no eth. I dont mind giving up a little on the bottom end if I have to to make gains up top, i can always prop for skiing or whatever should I wish. Some of the guys in that SST120 thread spun over 10K RPM :eek:

[FORBESAUTO]

There’s a lot of power the be made with porting, but on the other hand a lot power to be lost if not done correctly. If your not real comfortable and 100% sure of what ya doing you could kill it, much more to it than just port heights. Ole Rex used to angle mill the tops of the pistons all the way around on a few motors and worked great. It raised port duration on all ports without changing the size of ports keeping the velocity high for good low end and also helped in the “looping” of fuel charge to plug then to exhaust. Then again, need someone with experience doing this to how much and wear to cut.

[LakeFever]

Im pretty well set on doing this in two stages. Bolt on solutions for the 135, then rebuild the 150 XR2 and max it out. I have no fear whatsoever of attacking any portion of the build be it porting or machining or anything like that. My wife does not like me spending cubic dollars but does not mind me putting the hours in the shop so this sounds ideal over time plus I love to build, its what I do and i do lots of it.

So plan one; bolt on glory for this winter is there anything on the list I put in the first post that I shouldn't do or anything I missed thats relatively easy whilst apart?

If there are photos anywhere of TRex's work on those pistons im sure I could emulate. What happened to that guy? I have read a pile of his posts on here learning lots of cool things.

[FORBESAUTO]

Never saw any pics of them, he just told me about em and told me to leave about the size of a half dollar in center uncut and cut from there out to edges. Told me bout it just causally talking, and I’ve always said I was gonna take a stocker and try it, but never did. He got into fooling with his old Mopars and just hung up the boating. He was building his old Laser for river runnin and realized his shoulders were bothering him so much, didn’t know if he do it anymore and totally got out of it. Still love to go talk crap with him though, what a cool ole guy

[LakeFever]

He sure sounds like a cool dude, I'm glad hes doing well. It really is great to have good conversations with people who really know their equipment it can be a real laugh talking about all the foul ups learning about em too. I do enjoy this engine work and rigging the boat is a ton of fun Im not rushing the experience Im savoring it. This board is a great resource I really appreciate the high bar of knowledge and experience here, I'm getn a propur edgacaten'

I'm going to stare at those pistons and port specs a while when i get that thing tore down ;)

[Merc 2.5]

Never saw any pics of them, he just told me about em and told me to leave about the size of a half dollar in center uncut and cut from there out to edges. Told me bout it just causally talking, and I’ve always said I was gonna take a stocker and try it, but never did. He got into fooling with his old Mopars and just hung up the boating. He was building his old Laser for river runnin and realized his shoulders were bothering him so much, didn’t know if he do it anymore and totally got out of it. Still love to go talk crap with him though, what a cool ole guy


Well then u should tell him to stay on s&f to give out his awesome knowledge of these things:D. I also love reading his post!! (Mite take couple reads to figure it out) , but I personally under stand it all! But back to cherry 2fo. Was there no pics on byuboyz? Cant remeber , you may wanna talk James Perry (wrechin2) , he knows all the good tricks and would be happy to share the info. Absolute great guy ,, he actually has pics of 3 motor builds he did on Chattanooga fishing forum , go check that out also, if I had the equipment I'd be cutting on everything also:cheers: good luck

[LakeFever]

I wonder how far you could take the piston top down before the ring land becomes an issue? Not a whole lot of room there so this is thousandths of inches shaved not 1/4"s of inches

Merclover I found this on the fishing forum and there is a lot of pics, very clean work there too

https://www.chattanoogafishingforum.com/forums/thread-view.asp?tid=28345&posts=22&mid=218854&highlight=xr2&highlightmode=1&action=search

[Merc 2.5]

Yep he is the man. I'm actually goin get my block next weekend ,has had lite port and exhaust,

[Merc 2.5]

Also say if u deck pistons 50 thou, will also have deck block

[LakeFever]

I wonder if I could just shave more off the heads to make up for it?

[Merc 2.5]

I wouldn't know, never heard anyone do that, seems to me it it would throw everything off

[LakeFever]

Me either. Thinking once the pistons passed the ports its all about quench and compression at that point. Dont think it will matter much if its decked block or just milled heads seeing as the heads are basically on their own up there unless this messes up the chamber. Lots of unknowns for me this far out

[FORBESAUTO]

Yeah, ya only removing thousandths off the sides of pistons. Figure how many thousandths you wanna raise ports and thats how far ya go down, but not getting too close to rings. I would think taking about half the distance to ring land would be as far as I would go. The center height of piston don’t change, but you would have to take a little extra off head to make up for what ya lost from piston. Another benefit is that in a sense you also getting an angled squish band. I’ve always wanted to experiment with it, but all my blocks port heights are already too high to go adding more duration. He done on a few motors and one customers 2.5 and said guy called him back and told him it ran like a raped ape.

[Merc 2.5]

Reason for decking pistons is a quicker way to get port open little sooner. He had a chrome bore motor and d port piston and deck them was his only option unless resleeve but the block has to have it to keep squeeze I guess. Not sure if you can get the same by cutting heads? If you are porting block I wouldn't see the need in it then

[LakeFever]

Ya fare enough that all makes sense. I could see myself porting and tubing and all sorts of whatevering to that spare motor. I could also see myself buying a 2.5 when the right one pops up at the right time. This winter though I am modding this 2.0L for sure. Shaving those pistons is tempting haha crazy I have never shaved a piston down ever. Relieved some for valves here and there but shave? This will be a first

[FORBESAUTO]

Porting is the way to go, but can easily be jacked up not done right. I always wanted to try a blend of porting and piston to see what the hay would happen. Remember before ya go sycho crazy cutting, which is very easy to do when got the cutter in ya hand and an eye full of metal and can’t see straight. Making power out of these things is all about velocity on the charge side. Flow a little more important on exhaust side. I remember on my first build, I was over at Rex’s and was telling him I had done a little porting on my intake. He never said word, just went into his room where he kept all his intakes, grabbed a bone stock one and handed to me. Said here put this on, cause you done f***ed that one up! Told me he’s cut intakes every way imaginable to just get out done by a stock one, only improvement he’s found was from cutting ridges in a stock intake and that’s it.

[FORBESAUTO]

Just to be clear he’s not shaving whole top of piston, but cutting it to the shape of a tee-pee. I only threw that out there as an option if ya didn’t want to cut the ports in cylinder. Another tip he taught me was there is more power to be made on the bottom ports than top, ya can do what ya want with the upper ports, but if ya can’t get there and get it there on time your pissin in the wind.

[LakeFever]

I understand you splained it good n clear thanks! Its tempting because it sounds easy and fast vs grinder porting which is fiddly and time consuming. Yes porting the case, add tubes, tunnel porting, finger porting and all sorts of mods posted prior that i read. Not too sure yet how Im going to proceed there but if there was one or two quick porting mods that make solid gains? I would surely be a player this year for those