savage XL replacement engine suggestions

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craig911

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Location
Bristol, England
RC Driving Style
  1. Bashing
hey guys and girls

so my mac star .28 has well kind of packed in so I'm looking to replace it,

i have seen a few engines but not sure what to go for, i missed out on a force 5.9 auction i forgot about

i was thinking possibly a high revving .21 or something I'm not looking for wheelie power just something that will be reliable and have enough grunt to power through all the gears

i have my eye on a LRP Z.25R Sport, or possibly a force .32 engine my budget is not great at most I'm looking at £100

i dont mind getting a used engine but would have to be a hell of a deal
 
@craig911 the LRP .32 would make a great choice and highly recommended by many over at HPISavageForum.com as well!
 
@craig911 the LRP .32 would make a great choice and highly recommended by many over at HPISavageForum.com as well!

i would love to get a lrp .32 but its twice my budget allows if i had £240 to drop on one i would

if this mac star .28 was not such a pain in the rear i would replace the piston and sleeve for £50 but the tuning issues with its inconsistency from one run to the next i'm done with it,
i don't know if its a problem with the carb causing tuning issues but £35 to find out if that may be the issue on top of replacing the sleeve not worth it,

i have also just come across a listing on ebay selling new force .36 5.9 engines for £120 i know it wont be as good as the lrp .32 but would be a damn sight better than my mac star

my budget is £100 i can possibly push it a little if i find the right deal

engines i have found in budget or around my budget (NEW)

£70 - LRP Z.25R Sport
£99 - force .32
£120 - force .36
£99 - TT pro .28
 
I don't know anything about those engines listed. With a kind of short buget like that, trying to push that much truck, I would prob keep an eye out for a good used lrp .32 if at all possible.
Has your .28 always been a nightmare to keep tuned? Maybe it was running poorly and that had you chasing the tune all the time? Just a thought.
 
I don't know anything about those engines listed. With a kind of short buget like that, trying to push that much truck, I would prob keep an eye out for a good used lrp .32 if at all possible.
Has your .28 always been a nightmare to keep tuned? Maybe it was running poorly and that had you chasing the tune all the time? Just a thought.

it's always been a pain to get a good tune, i always reset to stock and go from there, sometimes it will run perfectly idle fine, going from idle to full throttle and in between would have no issues

other times it will ether scream for a few seconds when its returned to idle no matter how rich the low speed needle has been set or on the other end it will have weird issues at full throttle like be fine then struggle and then not want to go over half throttle without hesitating

i have just got some thick grease to seal the needles around the o'rings so will see if that sorts anything, i have a feeling that my carb may have issues, also why i prefer to have a carb that does not have a mid range needle ( not that i play around with it )

i have a feeling the carb may have an air leak or some other issue i would swap it but can't find one to replace it with ( want one without a mid range needle ) but the carb neck is quite large

i also got to get some fuel since I'm low
I'm using hpi optifuel - optimix 25 but going to switch to optimix race 9% oil instead of 14%
i was using VP powermaster 25% race fuel ( or there 20% master basher if the other one was out of stock ) but its no longer available in the UK last time i got to use it was early last year maybe end of 2015
 
I just bought a LRP .28 spec 4 for my LST XXL, it was 134 Euro from Germany. I suppose you are from GB, so you can buy it from there, something like 12-15 euro shipping within EU
 
Ok, so first things first... Have you made sure that you have good compression? Of your compression is shot, the rest of this may help you get some more time out of The engine, but the writing is on the wall for sure! Time for some sort of overhaul...
If the compression is good, all the rest of this is well worth the time and minimal investment! The issues certainly sound like air leaking AND needles all over the place. If it were mine, I would strip the engine down and seal it first. Obviously do a full inspect on all parts since its apart anyways. Sealing it answers the question for good.
I would be sure to check your idle gap. It sounds like it may be part of the issue. It may be moving all over the place and that will just wreak havoc!!! Lock it in at about 1mm gap.
The 3 needle carb is a bit of a mystery until you see it in a cut-away view. At least it was for me. It sounds like the second (mid) needle is there for ppl who "think" they are getting a TINY bit more out of the engine by tweaking it. I think it's a pain in the arse and something else to go very wrong! Lol!!!
Anyways, yeah, go thru the carb. Re seal the needles. I would use Associated Electronics 'Green Slime'. That is THE 'trick goop of the day' according to racers and builders alike. I haven't used it because I haven't had to rebuild yet. That is coming with the O.S. .18 CVR revival tho and I WILL be using it for sure! When the rebuild happens, clean out the whole fuel system. Do new fuel lines, clean or replace the fuel filter, clean out the tank etc... Make sure it's all nice and pretty like. ;) What I'm trying to get at is for you to eliminate ALL potential issues with minimal to no cost to you.
After you go thru the carb, be sure the pinch bolt under the carb is tightened!(after you seal the neck up) That's a common overlooked leak point. This link has good info on how to go about sealing an engine correctly.

https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/

Be sure your head gasket is in good shape as well.

Double check to be sure your linkages and your throttle servo are working smoothly and without any slipping or binding. Check to be sure you haven't got any stripped teeth in the servo or on the arm as well.
Everything I have listed here, with purchasing of all products etc shouldn't cost you any more than $25-$35 (US) not including the fuel. These simple repairs could very well keep you from having to replace that engine. Def let us know how things go and what you find as you dig in! Good luck!!!:thumbs-up:
 
Last edited:
Ok, so first things first... Have you made sure that you have good compression? Of your compression is shot, the rest of this may help you get some more time out of The engine, but the writing is on the wall for sure! Time for some sort of overhaul...
If the compression is good, all the rest of this is well worth the time and minimal investment! The issues certainly sound like air leaking AND needles all over the place. If it were mine, I would strip the engine down and seal it first. Obviously do a full inspect on all parts since its apart anyways. Sealing it answers the question for good.
I would be sure to check your idle gap. It sounds like it may be part of the issue. It may be moving all over the place and that will just wreak havoc!!! Lock it in at about 1mm gap.
The 3 needle carb is a bit of a mystery until you see it in a cut-away view. At least it was for me. It sounds like the second (mid) needle is there for ppl who "think" they are getting a TINY bit more out of the engine by tweaking it. I think it's a pain in the arse and something else to go very wrong! Lol!!!
Anyways, yeah, go thru the carb. Re seal the needles. I would use Associated Electronics 'Green Slime'. That is THE 'trick goop of the day' according to racers and builders alike. I haven't used it because I haven't had to rebuild yet. That is coming with the O.S. .18 CVR revival tho and I WILL be using it for sure! When the rebuild happens, clean out the whole fuel system. Do new fuel lines, clean or replace the fuel filter, clean out the tank etc... Make sure it's all nice and pretty like. ;) What I'm trying to get at is for you to eliminate ALL potential issues with minimal to no cost to you.
After you go thru the carb, be sure the pinch bolt under the carb is tightened!(after you seal the neck up) That's a common overlooked leak point. This link has good info on how to go about sealing an engine correctly.

https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/

Be sure your head gasket is in good shape as well.

Double check to be sure your linkages and your throttle servo are working smoothly and without any slipping or binding. Check to be sure you haven't got any stripped teeth in the servo or on the arm as well.
Everything I have listed here, with purchasing of all products etc shouldn't cost you any more than $25-$35 (US) not including the fuel. These simple repairs could very well keep you from having to replace that engine. Def let us know how things go and what you find as you dig in! Good luck!!!:thumbs-up:


engine still has very good compression, i'm going to grab some high temperature silicon sealant for the back plate and around the carb
i have some 300000 cst silicon oil i'm testing on the needles if that works then i will know since its sticky as hell

everything has already been checked
 
https://www.walmart.com/ip/Permatex...93696&wl11=online&wl12=19278837&wl13=&veh=sem

The high temp with the sensor safe rating is the good stuff. ;) Def post about how the silicon oil works on the orings! I'd love to know! Make sure you tell us what it is and where to get it too. :D ALWAYS good to have access to the top notch products!!!

The silicon oil i'm going to test brand - Corerc 300000 cst i had some for my savage diff so have a full bottle it's super thick and heavy so will stay in place and won't run off or evaporate
i have also just ordered some silicon sealant K2 High Temperature 350°c
i will use it on the back plate, around the carb and on the pinch bolts

its a love hate relationship with this engine
 
You can seal the actual neck on the carb as well. One less poss issue. Don't forget, make sure it's sensor proof. ;)
 
You can seal the actual neck on the carb as well. One less poss issue. Don't forget, make sure it's sensor proof. ;)

that's what i meant haha the sealant should be here in a few days so will update when it's sealed
 
Ah, gotcha! Just want to see you get this beat! I think you have a good engine with some issues but not enough to just throw in the bin. :thumbs-up:
 
Ah, gotcha! Just want to see you get this beat! I think you have a good engine with some issues but not enough to just throw in the bin. :thumbs-up:

if i can't get it running properly it will become a spare/desk ornament i replaced the front bearing a few days ago I'm not ready to completely give up on her yet, when it does run properly it has loads of power especially pushing around my truck with the huge wheels it has fitted

i have it paired up with a novarossi EFRA - 9901 pipe although could do with a manifold that better fits the savage than the 41021 but i'm happy with it


when it does die its piston and sleeve will be placed on my key ring to join a thunder tiger .12 and a force .28
 
ok so for whatever reason my engine is now refusing to start, but i will keep trying, i have not received the sealant yet but will use it when it arrives

I'm having no luck finding a lrp .32 in budget and used the chepest i found was £140 and i can't justify spending that on a used engine that i know nothing of its history

i think i will pick up a ofna force 5.9 since it's just over budget and brand new, i know it probably won't have the same power as the lrp .32 but will be a damn sight better than this mac star .28 i will not be getting the new engine for a few weeks so until then i will keep trying to get this mac star running
 
Well, as the old adage goes... you get what you pay for. If I were you, I'd just save up for the LRP32. I've been in the hobby for nearly 20 years. For the first 5 years or so, I dealt with cheap budget engines. At the time, there were many. Then I got my first $200 engine, OS18TM for my revo. A few years later, got an LRP28 for a savage for $170. I have to say, I spent far less time fussing with the engines once I got over the $150 price range. I have an LRP30 in my savage now, an OS21Tm in one of my revo's and an LRP28 in my other revo. Rarely do I have to fiddle with an engine anymore. Just start, adjust the tune a little for the weather and run it for 4+ hours without thinking about it.

Also, they last a lot longer. Out of cheaper engines, I'd get maybe 4-6 gallons before compression started getting weak. Now I get 10+ without a problem. So, they may cost twice as much, but they run easier and last twice as long. :)
 
Well, as the old adage goes... you get what you pay for. If I were you, I'd just save up for the LRP32. I've been in the hobby for nearly 20 years. For the first 5 years or so, I dealt with cheap budget engines. At the time, there were many. Then I got my first $200 engine, OS18TM for my revo. A few years later, got an LRP28 for a savage for $170. I have to say, I spent far less time fussing with the engines once I got over the $150 price range. I have an LRP30 in my savage now, an OS21Tm in one of my revo's and an LRP28 in my other revo. Rarely do I have to fiddle with an engine anymore. Just start, adjust the tune a little for the weather and run it for 4+ hours without thinking about it.

Also, they last a lot longer. Out of cheaper engines, I'd get maybe 4-6 gallons before compression started getting weak. Now I get 10+ without a problem. So, they may cost twice as much, but they run easier and last twice as long. :)

I'm holding off on the new engine for the moment since i got it to finally start earlier but was having idle issues kept jumping up and down (had not sealed it yet) and only had it idle to make sure it would consistently start,

i do feel there must have been something else going on that i did not pick up on and the carb may have been a large part of the puzzle, out of all the engines i have owned this has been the most annoying and temperamental,
would love to have the xtm 24.7 that i fitted in my thunder tiger tomahawk st wish i kept that engine when i sold the truck that engine was amazing

i removed the backplate and sealed around it and removed the carb and applied sealant around the neck and on the pinch bolts, also applied sealant on the screw under the pinch bolts, (not my engine but you can see the random screw under the pinch bolt) what would that screw have been used for?
macstar.JPG


It would also appear i have sorted the needles with the 300000 cst silicon oil, the low speed needle is much easier to adjust was quite stiff before can't remember what i used on it last time, also seems to have fixed the issue with the mid range screw it felt too loose but the thick oil has stopped it feeling super loose, it was way too easy to turn before you could do it pressing your finger against it


genuinely curious has anyone ran or have experience with a LRP Z.25R i can't find any info about its power output, claimed rpm etc i know it would not have the grunt for the savage xl just interested in its potential uses in a standard savage X with 3 speed, tempted to swap back to the X chassis
mainly asking as i don't need huge acceleration just want a reliable engine
 
For me, the LRP28S3 was plenty for the savage X. Odds are, the 25 will be too. If/when my LRP28 in my big block revo dies, I'll more than likely go with the LRP21 to get a few more RPM's and more controllable power.

I think that screw at the base of the carb neck is for a boost bottle. Something that was big back in the day to aid in atomization of fuel and help keep consistent pressure inside the engine when it runs I think. From what I recall, it didn't do much for our RC's. For me, it just seemed like one more place for air to leak in or out.
 
For me, the LRP28S3 was plenty for the savage X. Odds are, the 25 will be too. If/when my LRP28 in my big block revo dies, I'll more than likely go with the LRP21 to get a few more RPM's and more controllable power.

I think that screw at the base of the carb neck is for a boost bottle. Something that was big back in the day to aid in atomization of fuel and help keep consistent pressure inside the engine when it runs I think. From what I recall, it didn't do much for our RC's. For me, it just seemed like one more place for air to leak in or out.

thanks for the info, just saw that on the replacement crankcases it was no longer present,

i did not know what purpose it served as there was no mention in the manual for its use although i did see a few other hobao engines with a line from there to the back plate of the engine just was not sure why,

i will give an update later of how this engine runs now its been sealed, put it back in the truck last night ready just got a few things to do then will test it out
 

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