OMC 3 Cyl expansion Chambers

[johnsonracer]

I am currently in the proccess of building a 3cyl 920cc omc to run pipes.

Has anyone done this? I have had the side of the block milled and welded up to fit flanges. Obviously plugged where the exhaust used to exit so the cooling water doesnt escape down there.

What is everyones comments on expansion chambers over pure megaphones?

I will build a set of megaphones purely to run it at night and get some footage of her thrown flames out!

Everything else has been done to it. 19s fron half. Finger ported, head work etc etc. The never ending quest for more speed has brought me to exhaust work.

[Detroit Whitey]

You need to talk to Tim Kurcz

[johnsonracer]

Ill try get in touch with him, cheers.

[Mark75H]

Steve Benson built some with expansion chambers too. Years ago his were among the fastest.

Both guys are members here on BRF and have posted recently.

Expansion chambers will make 30 to 50% power increase, megaphones 15-18% max.

[Mike Schmidt]

E mail me at teammsr@comcast.net or call me at 860-349-9310 and we can talk.

Michael D-1

[BRIAN HENDRICK]

This is a 497 set up as a FEH with very nicely engineered triple expansion chambers. It ran quite well in Reg-2 about ten years ago. However with the advent of the Runne 'pulse' tuned system, it was no longer (as?) competitive. I suspect that as the motor was designed to be 'pulse' tuned, that simply bolting on a set of pipes will not be effective, unless you were to re-engineer the porting. But nothing ventured, nothing gained.

[David Mason]

This is a 497 set up as a FEH with very nicely engineered triple expansion chambers. It ran quite well in Reg-2 about ten years ago. However with the advent of the Runne 'pulse' tuned system, it was no longer (as?) competitive. I suspect that as the motor was designed to be 'pulse' tuned, that simply bolting on a set of pipes will not be effective, unless you were to re-engineer the porting. But nothing ventured, nothing gained.

Brian,

If that is the rig that Fitzgerald ran, it was Mike Lopez rig that Benson built. Benson had some fast chambers in the time. I have no doubt the chambers, when combined with the right porting and other modifications within work very well.

There is no bolt on chamber that would give you the best a chamber can deliver. At least not one I have found, or heard of. Maybe someone has hit on something ?

[John (Taylor) Gabrowski]

These days you see faster changes in technology in the 2 stroke racing snowmobile arena in North America then anywhere else.

You do see many 3 Holers with 3 pipes (but they are fully supported in sled bodies and platforms) but you also see many sled 3 Holers with a single pulse tunned manifold coupled to a single expansion chamber as the system used. Their horsepower is very bizarre.

Such a single pulse tuned 3 cylinder coupling exhaust manifold coupled to its design expansion chamber would be a practical route for a OMC 3 Holer to increase horseower yet instead of the pulse tunned manifold and dump pipe you see commonly now or the Lopez unit of a decade ago. Too many pipes you have breakage too boot where a single design expansion chamber and pulse tune manifold is a happy medium between that and pulse tune manifold with dump pipe. What will racers do? Study snowmo racing information sites and think about it.

Thing is you add more horsepower and another prop what do you do with the raceboat technology to handle significan increases in horsepower?

[johnsonracer]

[QUOTE=

Thing is you add more horsepower and another prop what do you do with the raceboat technology to handle significan increases in horsepower?[/QUOTE]

At the moment the bout is doing about 90MPH

I have heard of this exact hull doing over 100 easily with a 31M engine on it.

I am quite confident that if I can get the boat to do 100-110MPH it will handle it nicely. I don't want to buy a 31m and bolt it on purely because I want to get the boat going that fast, not just buying somebody elses motor to get me to that speed...... Kind of got a point to prove to a few people.

[David Mason]

The technology is not as simple as adapting from the sled to our outboards. The engines in a sled are radically different than our outboards from OMC. They will get you in the ballpark, and are a good starting platform, but you will be dissapointed if you simply bolt on a set from the same CC engine.

Put three chambers on a sled that has only a 3 into 1 configuration and see what happens.

Johnsonracer, where are you from ?

[John (Taylor) Gabrowski]

David M:

Concerning your previous post and I think that you would agree is that most people here that have had some exposure to expansion chamber systems, pipes and formulas go way beyond the simple thinking that you could put anyone's 3 Holer pipe from any other brand or type or modified version and that pipe from some simliar displacement engine would even begin to work if at all. Pipe formulas are based on precise engine specs that the manufacturer of builder would know or would provide as one relevant start point and from there it is test to fine tune the pipe. The ghist was that there is the technology out there that shows that a single expansion chamber matched to a 3 holer can work well and not be a great weight that could be constantly breaking and needing repair compared to some triple bunch of heavier or vibrating a pipe system that would.

That is all I was ever trying to get across. :)

[johnsonracer]

I have a mate that is a good fabricator so he will be making me a set of pipes. Been reading a bit about the chmabers now and the different formulas to use to custom make pipes to suit my engine.

From N.Z

[formeone]

luv my pulse tuned exhaust i build,,, can deff feel pull and set record with it,,,goooo figg,,hehe

[johnsonracer]

What sort of motor did you build pipes for?

[BRIAN HENDRICK]

luv my pulse tuned exhaust i build,,, can deff feel pull and set record with it,,,goooo figg,,hehe

Cheyney, that 45deg elbow from the '59 Oldsmobile 98 will be hard to find these days;)

[formeone]

motor was just a form-e/850 legal motor... dennis westby used it also to set nbra comp record as well... remember might make more top end horsepower ,,, but will only have a very narrow power band,,, just like mickel lopez had to run small wheels especially with his overdrive,,, my props about 9 inches in dia.... and way up on pitches,,, the time and money spent building something like that ,,, youd prob go faster buying new props and a tach,,,, just my opinion as i am thrifty also,,,,,,hehe... haaa as for a 59 olds hec that part expensive,, me cheep went to schucks 3$ for u bend,, works great,,, if ya know where to cut it,,,hehe

[johnsonracer]

whats the fastest anyone has hone up where you guys are with a 3 cyl.
Is there different records for hydros and tunnels?

[Mark75H]

formeone (Cheney) has gone the fastest, 104+ with a hydro

Yes, there are different classes that ran tunnels with triples in circle racing, but I think that class's top record was actually set with a hydro too, at about the same speed.

[Popa Sam]

I thought Jimbo set the Kilo with a mod 50 tunnel at 112-115 range. I have it somewhere will have to look and see.

[Mark75H]

I think you have the right brand, but are off on the driver and speed, if I recall :)

[Tim Chance]

Along this line, and I hope I have all the info correct. Sometime in the 1970's Billy Seebold and Mercury wanted to set the OE record with a Mercury Mod 50 motor on a hydro. Billy and Andy Lowrey built a 14' Hydro in Billy's shop. It was a nice looking boat with a tunnel boat type cowling and painted Mercury Black.

At that time Konig held the OE record somewhere around 117 mph with an alcohol buring 40c.i.+ opposed 4 ( a genuine racing engine). The fastest speed they could get out of the 3-cylinder Mercury was 109. They gave up.

Billy gave the boat to Paul Bogosian and since Pauly only drove runabouts he put his D Konig on it and I raced it one time at a race in Springfield, Illinois. I finished second to Jerry Kirts. The boat was a handful. We were going to change it somewhat so it would corner better before we ran it again. We had it at the Home of Kenny O**. Some time went by and Pauly asked Kenny about the boat. Kenny answered something like "I didn't think anybody wanted it so I took it to a landfill".

Needless to say Kenny was and still is an idiot.

[Popa Sam]

I think you have the right brand, but are off on the driver and speed, if I recall :)

Jimbo set the kilo record for mod 50, 10-18-80, speed was 112.721

[Danny Pigott]

I thought Jimbo set the Kilo with a mod 50 tunnel at 112-115 range. I have it somewhere will have to look and see.

Fred Hauenstein set the MOD 50 kilo at 107 mph with a Bellcraft Hydro in 1975. I am sure he was using a 19s engine. Jimbo later set the MOD 50 kilo at I think 110 mph in a Tunnel ,I am sure he was using a 31 are something close. After testing my MOD 50 an could not get it to run over about 88 mph I called Jimbo an asked what the problem was. He said that there were MOD 50's an then there were MOD 50's. He told me that 85 or so was about what a reg. MOD 50 would run. At that time we did not know about all work going on with the OE program. Paul Kalb had told me about the European OE so I called an talked to him, an he sent me the spec's. now I knew a little more.

[Mark75H]

ok, thats not the record I was thinking of, but it both is and is not the motor being talked about here.

I'm sure Jimbo's record was set with the special cast block with the transfer and exhaust sides reversed and 3 2 barrels

The record I was thinking of was set by Fred Hauenstein with a more conventional OMC Mod 50 triple. The speed was pretty close to Cheney's.

[formeone]

fred ;s is the closest to mine , on a normal hydro,, but remeber they where all mod 50 motors 3-2 barrels and all... we limited to sock one barrels,,,,.. and 6 reed openings where they werent,,, i can always run about 92-93 in comp... with acceleration,,, supposedly a couple calif's can also these days,,, not sure aboutthat ,,, but first time out on dennis westbys apel we showed 93 ,,,,, he later set nbra record... i showed 106 ,5 a couple times when went threw kilos just couldnt back it up at the time,, but am trying for higher speeds now hopefully in next month or so ,,, we shall see,,, i know boat dimensions play a very big roll in how fast ya can go with these and exhoust is crucial on these motors,,, and i run the older square block esier to work with i think and lighter... have seen lots of similar exhaust like mine but never any that preformed like mine,,, go fig...someone always think they know better ooo well,hec i didnt even have a tach when did my stuff orig,,,,cheyney

[johnsonracer]

Cheyney, you lift the exhaust timing much?

Is MOD 50 formula 3 over there or different? Our Formula 3 is outboard up to 1000cc or inboard hydro to 1650cc

We can do what ever to outboard. As much time and money as you can put in.

Have to run non alcohol based fuel (av gas maximum) and non turbo or NOS'd

[MTECHMARINE]

My MOD 50 was crisp right out of the box, I got it thru Bill Glennon as MR. T Ireland was not a booster of mine after I got his SE boat tossed at the Modesto kilos in 1975. It ran really well the 1st year I had it, but after replacing pistons for the second season I stuck it up and broke a port web. Sent it to the factory for reconditioning and when I put it back together it never did run like original. The "snap" was gone. Wonder what happened?? As well as the second generation with straight in induction being on the blessed few's boats. Finally sold it to Greg Jacobsen in 1980. Put a formula 100 4 throat strangler V4 on the 50 boat and it was formidable!;)

[Roy Hodges]

Were rotten. Petty & Paul Bender set a new S E record , from about 64 mph , up to 83 mph , then got disqualified for being 5 pounds light. The scales were crap, in my opinion . I had seen that old set TOSSED into the back of a pickup many times . They dated back to mid 50's ,in the old "Central California race rules commitie" , that preceded the CCRA.Bender offered to pay the entire sanctioning fees , insurance , etc. for That Sunday , the officials refused, not wanting an OMC to take the S E record. I was there , i know .That weekend a hydro took the "new" S E record at only 69 mph, with a 75 stinger, or evinrude hustler, not a good match on a hydro .

[MTECHMARINE]

I agree, it was a weird weekend.

They were adding gas on the scale to make the weight! I was the guy with the hydro, the thrust socket broke halfway thru the 1st run and kicked the engine way under. In any case I would not have run as fast as Petty'83, I think we were at about 78. Boat was built by Ed Karelsen just for this effort. Wartinger and I worked a lot with it to get up to 78. Your right, A tunnel was the better way to go.

Petty finally broke the record 2 years later at D lake in Oregon, and I was the inspector!!

[Tim Kurcz]

As Cheney points out, the exhaust system is everything to the OMC loop triple. My legal FEH does 95-6 in competition on a 3/4 mile course. I get fearful for my life so I back out at 102-3, but it's not out of steam there. My Mod-50 copy accelerates from 50 to 100 in 5 seconds!

Fixed chambers may be good for snowmobiles with torque multiplication, but not for outboards with fixed drive unless they're sliders. Simple math says the pulse tuned meg system is lighter, less complicated, and has proven itself time and time again in competition.

Since Bud Parker and I built the first one in 1993, I've sold over 30 copies of the factory system and have three new ones for sale. In 2007 the first 3 places at the APBA mod nationals had this system. Send me a private message if you're interested.

Tim

[calvin]

Great lookin exhaust Tim..is the exhaust open all the time or is it manually operated..like slider pipes?

[Tim Kurcz]

My system is a near dimensional copy of the factory Mod-50 except it's external to the engine and has a top outlet. There are no steering bar clearance issues to deal with, but most importantly, no water vapor contamination as with a down outlet system. Simple, lightweight, and effective, it does not slide. I've got two of the three remaining as shown with electroless nickel plating at $595 each.

Tim

[johnsonracer]

Hey Tim,

How do you think that exhaust would go on the bigger 60ci (920cc) engine if I could adapt it to fit?

[johnsonracer]

sorry its 56 ci not 60. But the loss foam powerhead with the cast in exhaust

[Tim Kurcz]

sorry its 56 ci not 60. But the loss foam powerhead with the cast in exhaust

Pulse tuning is a phenomenon of design with triples firing 120 degrees apart. This type of system is employed on the SST 60 internally, and will work well with your 56.6 externally. Meg length may need adjustment to suit your desired RPM range, but this is easily accomplished because it's external.

Keep in mind the Mod-50 (49.9) system was designed to tune in the 7000-8000 RPM range, though mine turn 8500 without going on their nose. I've got a 6-pack SST 60 in construction and will pulse tune it just like the factory, but internally this time, to keep it quiet for testing, and so nobody can see my work!

Tim

[Mark75H]

Tim, can you explain how the internal lengths are arrived at on the internal 3 bank tuner?

[Tim Kurcz]

The short answer is you disassemble the well designed and proven factory Mod-50 exhaust system, carefully grid and measure it, then duplicate close as possible for external use. The longer answer starts with port-time-angle-area equations and lots of math from Jennings, Bell, and others. There are additional improvements which I've made, but those are reserved for my engines only.....

Tim

[Mark75H]

So this is all based on Ray Nydahl's work?

[Tim Kurcz]

Hey Sam,

I'm not familiar with Ray's work. If you or any others have any documentation to share I'd like to see it. Clearly there has been alot of lakeside R&D over the years. Likely there's little truly new except for materials, computer controls, and propellers. The rest is test-test-test!

[Mark75H]

I'm pretty sure Ray is the source of the "proven factory Mod-50 exhaust system"

[David Mason]

If you want to go fast with a 49 cuber, you must run a exhaust system that works. Fixed chambers will work great fo rmaybe a kilo run, if you get it right. For competition races, you need something like what Chenny and Kurcz are using. I have one of the original Mod 50 exhaust systems along with many other people that race in FEH. They work very well, however there is room for improvment today. One can take a stock exhaust system from that engine and do a little carving and achieve decent results. The engine I won the APBA and AOF Nationals with was using a stock exhaust system slightly modified.

There is no one magic pill for exhaust. A lot depends on other factors, such as porting, and some other measurments. The beauty of this class is the fact that there are so many blocks out there one can experiemnt for a very small amount of money. I can honestly say that all of my 49 CI blocks I have tossed in the trash with failed experiments would not even come close to the cost of a current DSH or Sidewinder.

Back to the topic of exhaust. You need to find what works on your own application, boat, weight, etc make a difference as well. You can adjust porting to accomodate some things, thus changing exhaust math.

Like Tim said, there are things done on his system that he does not disclose.

[johnsonracer]

Hey Tim,

Does your exhaust come with that megaphone and everything?

I think it would be easier to adapt that to fit than fabricate pipes.

Top end is what I am looking for. I would like to be pulling near 10,000 rpm if possible.

You have a rough idea on how much to air frieght it to NZ?

[Tim Kurcz]

Yes, the meg, springs, and fasteners are included. As you can't use the lower plate, I'll separate that out. The nickel plated manifold, cone, and springs is $400 US. This will easily adapt as bore centers are the same for the 49 and 56 cubers. Send your address and I can get shipping information.

Tim

[johnsonracer]

I'll PM you with address :-)

With there being one megaphone for three cyls, does it affect the top cylinder differently to the bottom one? Being such a different length?

How would 3 of your megaphones go one one motor for example.....

DO you have any idea in power increase that system might add? When people talk about race pipes on two stroke bikes for instance they talk like 50% power increase. Thats huge!

[Tim Kurcz]

No, the plugging pulse is the same for all because of the close interconnect. The top outlet merely inverts the factory Mod-50 system. Three individual megs would eliminate the pulse tuning and go slower. Finally, anybody talking 50% by just bolting in a pipe is smoking hooch. Now, if you increase port timing to match the pipe, tighten crankcase pressures and increase cranking compression, and bump carburetion to match, then you've got something.

So, do you run in lake Te Anau?

Tim

[johnsonracer]

No I havent run in that lake. I am in the North Island. Have been to 4 or so lakes down south but not that one.


Another mod I am trying is copying the mod 50 type porting in the 56er.

With the main transfer going beine the sleeve in the 56 I am making some sleeves and pistons with the square transfer. I will put the sleeve in and fill the bottom to try match as closely as possible. This should increase crankcase comppression massively. I also thought the aire going through the piston (and finger ports) would reduse the resistance on the piston...
You tried this?

[johnsonracer]

What I am trying at the moment.

[Mark75H]

Excellent pictures, worth more than a thousand words each!

[Roy Hodges]

[QUOTE=Tim Kurcz;68935]No, the plugging pulse is the same for all because of the close interconnect. The top outlet merely inverts the factory Mod-50 system. Three individual megs would eliminate the pulse tuning and go slower. Finally, anybody talking 50% by just bolting in a pipe is smoking hooch. Now, if you increase port timing to match the pipe, tighten crankcase pressures and increase cranking compression, and bump carburetion to match, then you've got something.

So, do you run in lake Te Anau?............................................. ..........................................
.................................................. .................................................. ..................................
.................................................. .................................................. ..................................
I guess I'm very dense, having to ask this question. Is the reason for the outlet out the top , so that water don't enter the engine while launching the boat? Or since exhaust is hot & light , and rises ,i guess ,does aiming it up help scavenge the engine exhaust ?

- Roy Hodges

[johnsonracer]

I'll take agues Roy, I think its at the top so it doesn't foul on the midsection or steering etc... Let us know if i'm wrong Tim.......

No I don't run in Lafe Te Anau. I notn know if anyone else does. I havent seen it on a programme in the past few years.

[Jeff Akers]

There are some that belive that the "up exit" is more beneficial to exhaust scavenging . There was some discussion on the subject in the original "Fast Fred's Secrets of the MOD 50 thread", I think the discussion starts around pages 9 to 11.

[Tim Kurcz]

Johnsonracer: 30 years ago I spent a month in Kiwi and happened to drive a race boat while visiting friends in Auckland (after touring the south island from Christchurch). It was a very good roughwater Chrysler powered 25 cu inch v-bottom runabout about 11 ft in length. I sent some Michigan Wheel 2-blade racing props back from the US to help the fellow out, but lost track of him years ago. NZ is a truly wonderful country. My dream is to visit again, and retire there a bush pilot. The possibilty of racing boats would be like foam on a fresh Lion's brew!

Anyway, the obvious advantages of top outlet exhaust are:

1) No interference with steering as with my earlier down outlet versions.
2) No hassles incorporating the Mod-50 exhaust inside a closed tower or under a "stick" style tower as through ducts are always challenging.
3) No uncontrolled water vapor contamination of the exhaust system from cooling water dumps, vacuum pockets at/near the hull, hosing from roostertails, etc; the meg points back away from the boat, not sideways.

Note there is a small sump and drain hole provided in case of rain or other accidental aft watering. I've thought of adding a John Deere style "rain cap" flapper just for grins, but didn't want to spend the engineering time or add weight/cost.

Basically, if you're tower is so short as to submerge the bottom cylinder upon launching, a piece of tape could be applied as a temporary measure, or the 1/16" hole could be plugged or welded shut.

There may be serious engineering reasons why a top outlet might work better than a bottom, but they don't matter. I built the best possible, reasonably priced copy of the highly effective factory developed Mod-50 racing exhaust system. It just plain works.

Tim

[Roy Hodges]

DON'T do it ! I had one on my Lincoln SA250 diesel welding machine ,and even as loud as the exhaust was, the cap drove me crazy ! I threw it AWAY !

[johnsonracer]

I am liking the idea more and more of the pulse tune. I guess you guys and omc have spent lots on hours designing / testing. If I were to pipe it I would be stating from scratch.

The blocks at the welders, so when I get it back I'll make sure its going to work before i order.....

Tim, if you ever planning a trip to Kiwi land I'm sure I could put you up, same goes for any other race guys wanting to visit N.Z.... As long as you not gun weilding wacko's!! :-)

[Fast Fred]

So,
Tim Kurcz was thinkin maybe you could help me out, gots me one of them thare "Straight in" Modas, gots every thing i needs for it but she has a worn out liner. think you could share how you worked that out with yours . like if ya needed them, ware you got them, who put them in, and when thay were done how thay looked compared to the factorys, and how much about the cost. any help would be cool.
thanks
FF
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[Tim Kurcz]

Hi Fred,

Nice looking 10-port. Try LA sleeve. They built replacement Mod-50 sleeves for years and still have the drawings. If no luck, let me know and I can machine/install them for you.

Tim

[johnsonracer]

I Have one of those motors too.. I have never assembled it because the exhaust exiting out the bottom doesnt fit my mid. Bot with that exhaust system of yours this will solve that.

I have all the parts, even 3 new rings. Which motor would be recomended for top speed? I cant help but think that more C.I's is always better.

[Tim Kurcz]

OK on the Kiwi trip, and I was only teasing about the exhaust flapper!

Otherwise, the 56 never saw development like the Mod-50. Rumour is the typical six-pack 56 will make 100 +/- HP, where the US-factory Mod 50's were 110 +/-, and the European F3 with it's reversed exhaust was supposed to go 120 +/-. Though delivering moree power, the Mod-50 is a known piston burner and less durable. My best FE racing engines are good for only 10-15 hours hard race time with the fishing blister sleeve design before they wear out (two-three years Mod racing). The pressed sleeve (factory) race engine has better piston support and durability. But be aware this engine is extremely sensitive to fuel quality and delivery and propping (don't lug it). I've got boxes of melted pistons to confirm it, all burning Avgas! That said, it's a tremendous rush of power on as light boat.

Let me know when you're ready for the exhaust. It will make your engine lighter and less complex, and is known to work.

Tim

[johnsonracer]

The engine I am building is for a Kilo run. So low down etc is not an issue. I need to get 103mph so the best suited engine is the one I'll be going for...

[Tim Kurcz]

Then the 50 will likely do better and is easier to build with up exhaust. Either will benefit from the Mod-50 exhaust system.

[850cc racer]

Hey Johnson racer, what record are you going for?

[johnsonracer]

I want the New Zealand F3 speed record.

Currently its held by a Hydro with a 1650cc inboard. A tunnel has gone 92mph in NZ in a kilo. No one thinks I can do it, but I'm sure you guys and around the world are breaking the 100mph with tunnels.

[johnsonracer]

Could some one tell me exactly what I have here?? It only has one bridge in the exhaust, so two big square ports...

Should this be the engine I build up?

[Tim Kurcz]

That's a pressed sleeve OMC factory Mod-50 block and exhaust side system. Do you have the front end and hemi head also? There's your kilo engine if you can get the rest of the parts.

[johnsonracer]

I got everything yes. The only problem with it is someone carved the exhaust too much and broke the aluminum bridge so I will need to get that repaired.

Also from memory they plated with the port heights too much and turned it into a dog....

Do you or anyone have a port map of it to make some new sleeves?

[Tim Kurcz]

From memory, the port map was published on Fast Fred's "secrets of the OMC Mod-50" thread. If you can't find it, send him a request.

[Fast Fred]

5.050 from crank center, a lot of chamfur on the top, like a fixed power valve.
1 3/16" Mod50 carbs be best for a kilo:cool:

sleeve part number , L.A. sleeve FL041ob:eek::cool:
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[Tim Kurcz]

Hey Fred,

Looks like you've got a new sleeve there. Did LA have them in stock?

[johnsonracer]

Hey Fred, thanks heaps....

I also need the heights for the other ports.... Someone really went to town on this motor...

Was brought from Aussie

[Fast Fred]

i made a trade a ways back for a copy with all the specs,
lookin at yours for what i can see, looks factory. gots to run.:cool::cool:

[ima75man]

fast fred, give me a call dude.

[johnsonracer]

I cant imagine that the factory would grind the exhaust bridges so thin that they break..... like 0.075" thin

[850cc racer]

i dont have my rule book with me, however i know Tim Bollins has the aus speed record.. 103.99mph :eek: and i'd imagine thats with a 31M.. i can email him and check if need be!


I want the New Zealand F3 speed record.

Currently its held by a Hydro with a 1650cc inboard. A tunnel has gone 92mph in NZ in a kilo. No one thinks I can do it, but I'm sure you guys and around the world are breaking the 100mph with tunnels.

[Fast Fred]

ima75man:cool:

[Fast Fred]

ya, .075 is thin, new sleeve should be all spec'ed out, line it up,:cool: push it in:eek: bore and deck.:cool:

.004 interference fit on the sleeve:eek::cool:

[johnsonracer]

LA sleeve dont have anymore sleeves or make any more. Bummer

[Bill Van Steenwyk]

Some years back sleeves with a different porting arrangement were needed for an engine, and as it is a lot easier to remove metal than add it, "blank" sleeves of the correct diameter and height were purchased with no ports cut in them, and then the porting was done seperately by someone else to meet the need. Perhaps LA Sleeve could furnish "blank" sleeves of the correct dimensions and then using the afore mentioned "port map" they could be finish manufactured. If they are not availiable anywhere else, might be worth a try.

[Tim Kurcz]

Did you ask LA if they would make them in small quantities? If they won't, I can make them using a new one I've got in my possession, or from a sleeve removed from your block. Let me know how many you want and I'll quote.

Tim

[johnsonracer]

I asked them to supply blanks but havent heard back yet.

3 sleeves are needed Tim. The bottom cyl has been bored out and a thicker sleeve was put in. If this isnt factory I will have to give you diameter needed for that hole.

[Tim Kurcz]

You might also try Advance Sleeve Co. Buy a cast iron sleeve(s) with the correct OD, lay them out with the port map, and anybody with a Bridgeport can machine the ports. Also, you and Fast Fred both have examples to work from. Easiest thing to do is wait till your wife is out for an afternoon, wash the block in your dishwasher, bake it to 350F, then turn upside down in a wood box (to catch the sleeves as they fall out). The house might be a bit smelly, especially if castor was run in the engine. Anyway, once your wife is done giving you Hell, just take your best sleeve and the blanks to your machinist. While the block is empty, you can clean up the transfer & boost passages. Good luck!

Tim

BTW Installation is just the reverse. Just make sure you weight the sleeves while the block is cooling to keep them from creeping up. About 5# per sleeve will do it.

[johnsonracer]

Thanks Tim,

We have an oven at work for that! I can imagine the lady going wacko about the smell!! The oven sure does smoke when she gets up to temp.

I Always pull sleeves out to clean up ports and cut the sleeves.

I will be porting the sleeves myself. I like to do everything myself. I know its going to turn out like I want. Great experience and cant blame anyone else for mistakes.

My first engine I had a shop pull sleeves out for me and they broke them! From then on I do it....

Used to use the acceltelene welder to theat it up. What I mission! Thank god for ovens. I hear that hooded bbq's work quite well also.

[Tim Kurcz]

Yep, I know and appreciate you Kiwi's and your self reliance! Hat's off to you all. Good luck with your new sleeves. But, do you still want one of my exhaust systems? It is designed for that Mod-50 (with the plate). What am I saying? Knowing your culture, I'm thinking you've already got a copy under construction! LOL!!!

BTW: You should easy best the 92MPH NZ kilo record. If you get that engine to work like the factory, you'll easily do over 100. Fred Miller told remembered 106-108 in factory trim, 113-115 with a Vandervelden mod.

Tim

[johnsonracer]

I have a car for sale, hopefully she sells so I can purchase your system.

Otherwise it might be a delve into the up and coming "winter fund" gets quiet here in the Marine Industry..... Any work up there? :-)


I will be making some kind of exhaust to fit it. Have to see what the metal shop has avaialbe. I know it wont be as good as your system, but for the time being as funds allowed it will have to do.

My racing is self funded, I have 4 powerheads that I am trying a different approach on each. So dollars get pretty quickly chewed up buying gaskets, rod bolts and pistons/rings........

If weather allows I will be running that motor up tomorrow. I have modified some 1 3/16 carbs to try. Drilled and tapped in some Mid range jets where they are on the 1inch carbs. I think the 1 3/16 were in the bowls. I am fitting the propper bowls with their own fuel supply for low speed as the standard bowls caused me to die in corners when High speed was leaned off.

I am sure you know about the circuit I am talking about. Took me a few races to figure out why I was loosing low speed when leaning off the high.

[johnsonracer]

Oh...

And whats a Vandervelden mod?

[johnsonracer]

Here you go 850racer

[Seagull 170]

That water is too blue for Karapiro, where is that?

[johnsonracer]

Nelson in south island

[Powerabout]

Guys
If the log style into a megaphone works on a 3 cyl looper why did OMC design the V6 looper with a 3 into 1 and then down to the megaphone after several 90 degree turns?
( not like a Merc V6 which also is a trunk/log style)
Were they trying to improve the reverse pulse timing or something?
If you have ever seen a V6 Looper with the casting cut off it looks wierd
Powerabout