8th scale buggy engine
 

Ive been shopping for a new engine. I have a V spec that I have used last year but I would like to have something that I can use for most local races.
The Vspec has so much power, I dont need it for most of the racing I do. Plus a $300.00 engine in my opion is not really needed all the time. They have the HP but sacrafice life of the engine.
So I have been looking at 3 ports, cheaper and better miles per gallon (MPG).
Here is my list
Nova Top / Rex. (not sure whats the differance) :weird:
Collari
RB Concept

Did I leave any good 3 ports out?

I like the novarrossi engines myself, Rb would be a great choice for the money.It is a novarossi based engine so it is probly just a little bit better than the stock nova,rex or top 3 ports because of rb's quality control.

go to www.rbproducts.com for more info on thier engines.

Those are the 2 engines I have been looking at most.

Is the 3 port the way to go or should i get another 5 port like my V spec. I think the power band is a bit strong for some smaller tracks. Like a track that a 13 tooth clutch bell would be used or less then a 100 ft straight. Maybe im wrong. I know power is in the trigger finger but a 5 port has a strong power band.

nova/top/rex P5 turbo or standard are the best all round .21 buggy engines...............

He is right, the 5 port is the best all around motor.However when i saw the rex 3 port go i was supprised how much snap it had compared to my p-5, it just ran out of steam sooner.I think you will like the 3 port if your not looking for the blistering top speed.I believe they make more torque than the 5 port.

Hum for some reason I was thinking the V-Spec was a 3 port. :confused:

I dont dont beleave it is a 3 port, I have been wrong before.

OS V Spec
SPECIFICATIONS
Stock Number: OSMG2068
Displacement: .21 cu in (3.5 cc)
Bore: 0.653 in (16.6 mm)
Stroke: 0.629 in (16.0 mm)
Practical RPM: 3,000-40,000
Output: 2.5 hp @ 33,000 rpm

if it is its a very fast 3 port that has kicked many P5's ass. :cool:

Yea I went to there site as well to find spec's on the V-Spec and found what you found but no listing of ports. Im sure someone will chim in and tell us for sure.

It is odd that OS does not tell the port on the V spec.
I kind of went by the HP and RPM, based on other engines that are listed 3,5, or 7 port.

hi kyracer racer,

the V-Spec is a 3 port engine. (refer to http://www.rccaraction.com/articles/dyno_vzbvspec.asp)
however it does make excellent power due to its design.
but the OS is known to have a short lifespan (blown bearings, worn-out p/s)

btw, i'm surprised to find someone who doesn't want/need power.
but it's gd to hear that there's a racer out thr who's willing to go for a lesser powered engine for his races.

i'm curious, is your V-spec losing it's power? and that's why you're looking for a new engine?
if the OS is still okay, you can always 'detune' the power by using fuel with less nitro or more oil. using some pipes/smaller carb venturi will also bring down the power.

but if it's time for a new engine, go for an italian/french engine. they're longer lasting. i'd recommend you the following...
RB S5 or S7II (bout $10 diff) - both have a smooth powerband and are very reliable.
Werks Collari B3 - reasonable price and power. 3ports (if that's wat you're looking for)
Nova B21SB - budget engine and it's italian!

you didn't specify how much you were willing to spend on your next engine, but the above will cost prob ~ $200-240.

btw, nova, top and rex all come from the same factory, just diff branding and the rex uses a diff crankcase. the nova version is still the best imo.

hope my posting has helped you in some way.
cheers!

Funny you should ask about my V spec. The first one i had blew a connecting rod in about 4 weeks. I sent it back to OS and they replaced it. So far it is doing go but I dont want to take any chances. So I will only use it when I need more speed like larger races (Pro series). I am going to replace the con rod in my V spec and maybe it will last longer. Some say it is the bearings that suck and others say during break in the connecting rod gets worn. Who know, all I know is the V spec is not good.

Oh and all I have to say is WOW. The V spec 3 port is one fast engine!!

price range I am looking at for a engine and it does not have to be a 3 port now sense I have one :)
between $175 to 250.00

i replaced the bearings in my V-Spec to nova ones the day i bought the engine. hadn't had a problem since.
conrod breakage is due to the engine not properly warmed up during break-in, eg. idling 1st few tanks etc. the p/s being very tight will put a lot of stress on the conrod and OS ones are not exactly as durable as the italian ones (thank god they're cheap!).

looking at your price range, you'll get to choose from a wide range of engines.
go for an italian engine which is reliable and will last long if given loving tender care.
i'd highly recommend the Rb S7II. even tho it's a 7port, has good low-end and mileage. smooth powerband = easy to drive.
if you want a 5port, you can look at the nova plus21-5, specs are impressive.
or if you can wait, the ninja engines looks impressive. they'll be out arnd next mth or so.

personally, i've favored 5port engines having had a nova P5T, P5TX and a novamax M5T.
i've had an RB C5 which is more suited for large tracks.
and of course my V-Spec which i only use for races (like you i'm abit skeptical of its lifespan).

btw, i've just PM'ed you...

Nice reply Mr. Nerd! I don't run a V-Spec but I was pretty sure it was a 3 port.

I have run the S5, S7II, WS7I, B3 and the B7. All of which are very good engines for the money.

they don call me n.e.r.d for nothing! :smile:

but i'm still a very big fan of the V-Spec.
can't wait to see how the JP V-Spec performs... :eek:

http://www.mugenracing.com/JP-OS/jpos1.jpg
http://www.mugenracing.com/JP-OS/jpos2.jpg

btw speedbump57,

how's the collari B7?
heard it makes good power but i'm abit skeptical of Sirio based engines... :weird:

Nerd IMO the B7 is very much like the older WS7I or the newer S7II but with more overall power. It is very smooth and easy to drive hard. What impressed me the most was the top end power it makes. I got the engine about mid summer but didn't race it until the end of the season. I was tiring out different engines last season and for no reason I just ended up running it last. I know some team drivers that have had very good luck with them also. It will be the very first engine I run in the spring. :) I also have a P5X from EB that I really like. I have driven a V-Spec and I agree they are a very powerful engine but I didn't much care for the power curve. It just seemed like it was either on or off with no in between. It was not mine so maybe it wasn't tuned very well. It was fast though!

Bump

Thanks Dr. Nerd,
I will look into the engines you are talking about. I never thought about replacing my con rod with a Nova rod. My LHS has the OS con rod in stock but I guess I could tell them to order me a Nova one. I have know clue about the insides of the engine so is there any differance in Nova con rods or can I just tell the owner to order me a Nova .21 con. rod?

hi kyracer.

i didn't change to a novarossi conrod. i used novarossi bearings in my V-Spec.
you can get boca bearings too, heard they are quite gd too.

main problem with V-Specs is that their bearings are either gd and last a long time or they're lemons. if you get a lemon, it'll cause your crankshaft to vibrate and tt leads to broken conrods etc...
it's a 50/50 situation, that's why i decided to replace them with nova ones, no more worries!

pls do not ever use nova conrods in your V-Spec!, the internals are totally different.
and do get a new V-Spec conrod if you intend to rebuild you engine.

regards!

It was a typo on my part. I am in the process in replacing my con rod with a new OS con rod. Im not going to deal with changing bearings. I dont really know anyone that has the tool to do such a process. Not really to happy about putting more money in a defective product. I will stick with the plan. Add new con rod and only run my V spec at major races like Pro series or money races around my area.

I have a RB Concept 3 port on its way so it should work well for my primary engine.

Kyracer no need for a special tool to remove the bearings. Take the engine totally apart down to case and bearings. Pre heat the oven to 350* and bake about 8-10 min. Remove from oven with oven mit and gently tap on wood surface and the bearings will fall out on their own.

I read that in a mag. before, I thought it would be hard to put the new bearings back in. I guess what your saying is the bearings tighten up due to the heat stress over time.
Is taking out is the hard part, putting new bearings back in is a snap.

Well not really. What you are doing with the heat is causing the case to expand. The Alum case will expand quicker the steel bearings. To put them back in you do the same thing only in reverse. What I do when I am putting them back in is to heat the empty case again. Then place the front bearing on the crank shaft. When you pull the case out of the oven with gloves on slip the front bearing that is still on the crank into the front of the case. If you are quick you can remove the crank and place the rear bearing on the crank and slide the crank into the rear of the case and with a plastic end of a screw driver or a wooden dowel you can push on the crank to put pressure on it to seat the bearing straight. The crank should spin freely at this point, if not you will have to start over. I have never had to start over doing it this way though.

Hope this helps
Bump

Sounds easy nuff.

Thanks bump

:) ^

yup kyracer, go n get either the novarossi bearings or boca bearings for your V-Spec. (i think the bocas are cheaper and easier to buy online.)
it's worth the effort to get the bearings replaced.
that will settle your problems once and for all... :nod:

I'm getting ready to break in a P5X. Should I use a heat gun in the begining or just fire it up and let it idle?

Thanks

do use the heat gun..........

and don't break the engine in at idle...........if you're using a bench let it run at full speed..........at 80~100ºC

or run at the track with a rich setting and moderated accelerations....

What about the heat cycle method everyone is talking about. :confused:
I thought we were supposed to do the 3 5min cycles and 5 3min cycles :confused: And then run at the track.

IMO constant load is the key to achieve best performance and long lasting engines............

you can do that with a bench and a propeller only.........

do use a heat gun if you got one.
i don't have a heat gun so i make sure that the engine is primed and loosen the glow plug abit.
99% of the time the engine will start. immed i blip the throttle to bring the temp up. don't let engine idle or it will cool down and stall.
there are various breaking in methods. i've used the stephen bess method for most of my engines.
i'd wana try josh cyrul's method for my next engine. (see below)
http://cefx.net/tips/nitro/break-in/index.php

Wow!!! hold full throttle for three tanks (per Cyruls instructions) that seems risky. I understand the concept. He wants the top end so rich that it would probably stall at anything but full throttle. That way lots of fuel runs through the engine. Still seems risky to me.

There are so many different theories out there for engine break in it gives me a head ache :rolleyes: I just want my $300 engine to last a little while :nod:

I'll keep reading

One other thing. Why is the carb backwards on a p5x?? It's made for 1/8 scale buggies, yet the linkage is on the wrong side. I know I can just turn it around (can't I?) but shouldn't it come that way from the factory?

Boy, am I a nitro noob :blush: :D

running the engine at full throttle when it's running very rich is okay cos the RPMs won't build up due to the rich setting.
the engine will make '4-stroke engine' kind of sound.
if you go to RB's website, rody has recommended a similar way of breaking in engines.

as for the P5X's carb, it's still the old design. you gotta turn the carb around to do the linkage. when i got my P5TX, i was also surprised it didn't come with the new carb design...
the newer nova plus21-5 has the proper design which is meant for buggies...
then again, not really a big deal cos the main prob wif the old design was tt reaching the idle screw was abit diff, that's all... :p

this breakin thing is crazy. Everyone has a way. I thougth baby steps.
At first start the engine and just get it to idle vry rich. About 140 deg. After the tank is almost empty. kill the engine and let cool. Then start and do the same.
After that drive around about 1/4 speed for about 2 tanks. Then run about 180 deg. at 1/2 speed. Next lean out to 200 plus.

Now you have a nice golden brown pie ready to munch on. :D

N.E.R.D., do you have a link to the Stephen Bess method? I would like to read up on that.
Thanks

Here ya go D_ames

This was copied from a post by STEPHEN BESS on the "Starting Grid" message board as he tried to help another member get more life and performance out of his OS motor. This break-in method should apply to virtually any ABC hobby nitro engine (except for ringed engines).

If you are still idling at least a tank through during break-in, you're using the old-school accepted method (still works well for some!) but it's not the method that the top engine guys (Ron Paris, Dennis Richey, Rody Roem, Michael Salven are just a few I've spoken personally with about this) recommend anymore.

From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this mannerfor about 20-25 total minutes, it'll be ready for the track and race tuning. I realize this method goes against the old-school "idle on the box" routine, but you'll be amazed once you've completed this break-in routine, your OS will still have amazing pinch w/out sticking at the top AND your OS's compression will last far longer than it will with the "old school" method.

You say you run the engine at "factory settings" for the first FIVE tanks? That alone causes lots of stress, as the factory OS settings are very rich on every OS I've ever owned or tuned. The piston & sleeve haven't expanded to operating temps, and every time the engine turns over, the piston slams into the pinch zone at TDC. The not-so-surprising result can be a cracked con-rod at the crank pin--that's where the majority of the stresses occur as the engine turns over. I've only heard of about 6-8 OS engines breaking con-rods, and they're ALWAYS during the first gallon...and almost every time it's because the guys have performed the break-in procedure you described. Doesn't seem like a mystery as to why it's happening. Drawing out the break-in routine really stresses the engine & actually wears away compression along the way. This method I've outlined will feel weird at every step, but after you try it once, you'll notice a big difference in your engine's performance & lifespan.

Hope this helps; give this break-in method a shot--you have nothing to gain except longer life & more power

I have been using the new school method since I saw it and have recieved the best results as of yet.I have tried everything from breaking in on a stand with a propeller on it to the w.o.t. 4 stroking.I have to say the new school method in my opinion IS the best method. :D :nod: ;)

Thanks Speedbump :D

Your welcome sir!