Notices
RC Fuels Nitromethane, Castor Oil, Synthetic, heli fuel, 4 stroke, etc...Fuel Q&A is here!

oil content test

Old 08-03-2014, 04:10 PM
  #1  
rcbence
Thread Starter
 
Join Date: Jan 2013
Location: , OR
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Default oil content test

So I have an HPI savage 4.6 and firestorm. Bought a case if werks racing fuel last year. Both my 4.6 and g3.0 didn't last over 1 1/2 gallons.

I broke them in on the fuel using HPI idle method then running them after. Never let the temps get lower than 200f.

Engines didn't last. Sure I had some lean runs not being aware of the oil content. I'm sure I reduced the life instantly every lean run.
Never could get a solid lsn tune on either engine. Honestly had better luck with traxxas 20% fuel.

Both engines sure enough had the pistons go past tdc wear mark when disassembled. Lost compression when warm and lost holding a solid tune.

I'm not blaming the fuel 100% but will no longer run a fuel with so little oil. Especially the first few tanks when the piston is mating to the sleeve.

Werks has 6% total oil with a simple evaporation test.

Measured 300cc of fuel and poured in a tall glass. Lett it sit out a day and 80% was evaporated. Finished off with a heat gun barely holding a boil and was left with just oil.
Put the oil in my Byron's lube booster measuring cup that holds up to 1 oz or 30cc.

Poured all in and got 18 cc of oil. 300cc .06 is 18cc. Simple.

I find it amazing people saying.....wow! This fuel is solo good! It just revs up and get longer run times!.

I can do that too. Here's how.

Buy nitro. Buy methanol. Buy some klotz benol.

Mix 20% nitro. 5-6% castor and rest methanol.

More energy stored means longer run times and better revs because of less oil. Simple. That's how to make a solid race fuel.

I'm sure the pure 6% castor would protect better as well than a castor/ synthetic blend at 6%.

I did test traxxas power plus too.

Guess how much?

Most say that its crappy oily fuel. Runs hot smokes a lot must have 16% oil.

Nope. Its 10% total. 200cc of fuel. 20 cc was left over.

That's right. Less oil than byron race 2000 which is 12%

I find this hilarious in fact. That traxxas has less oil than everyone thinks. Now they say its a blend....but I believe its mostly castor. The smell while burning....plus the oil that's left behind is fairly sticky.

To make sure I'm actually close to the oil percent I tested some omega I have that claims 17% oil

This one I just measure up 100cc of fuel. If there's 17cc of oil then we got 17%.

And it showed about 16.....so close enough. Might be off 1% at the most.

So traxxas has at least 10% but no more than 11% oil.

Amazing how much more oil plane engines can handle without loading up real bad at idle. Not sure why car engines just don't run as good with 18% oil. Properly tuned on low speed they load up badly at idle and never really clear out unless you stay at wot.

Last edited by rcbence; 08-03-2014 at 05:03 PM.
Old 08-04-2014, 06:31 PM
  #2  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,054
Received 29 Likes on 29 Posts
Default

The HPI method to break in is utter garbage. That is 1/2 the reason your engines toasted when they did. The fuel may be partly to blame.

Traxxas Top fuel is a castor/synthetic blend, supposedly an 80/20 blend with the 80 being synthetic. In fact most commercially made fuels are an 80/20 blend more often than not.

I break in car engines on 18% oil airplane fuel most of the time. They handle the extra oil just fine, they just make more of a mess and tend to rev a little slower albeit near the same top revs as normal fuel. I only use castor oil in ALL of my fuel blends. I like to know what's in my fuel and more importantly I want to run the fuels the engines were designed for. Run a lapped iron piston/steel sleeve engine on synthetic oil based fuel and miss your piston seal goodbye. It would still run but some engines NEED the castor varnish buildup to keep the piston seal at or above par.
Old 08-04-2014, 07:26 PM
  #3  
rcbence
Thread Starter
 
Join Date: Jan 2013
Location: , OR
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Default

I started realizing this after I had engines wearing out rather fast. I don't understand why HPI has those instructions.

Thanks for the response. I'm gonna go ahead and start mixing my own fuel. Was disappointed when I tested some of my byron rtr 16 % oil. By volume it has 13%. So they cheat you on oil...and probably nitro as well. Have no idea what synthetic they use... But they tell me its the best. Like every other fuel maker lol. I see the pattern. They are all winning. Not to say its bad fuel.... By any means.

Last edited by rcbence; 08-04-2014 at 07:28 PM.
Old 08-05-2014, 03:10 AM
  #4  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,054
Received 29 Likes on 29 Posts
Default

Keep in mind, some fuel makers blend by weight and not volume. Volume is the accepted practice for most, which gives you the better bang for the buck over weight. The specific gravity of a given fluid changes with the air temperature so today it might be 13%, tomorrow it could be 12%.

RTR companies are aiming their products at new folks. Basically making everything as idiot proof as possible.

As as to mixing your own fuel.. Get a scale that goes up to about 12#. We have a digital kitchen scale I use. Figure out the amounts by volume you want in a given mixture. Now calculate those volumes as a weight. Once you have the weights of the individual chemicals sorted, put empty jug on scale. Add methanol to the calculated weight, and zero the scale. Add oil to the calculated weight, zero the scale. Do the same for the nitro. Add a few drops of your favorite food coloring and shake. I convert to mL as most specific gratifies are in metric - g/mL. Nitro is approx. 1.16 g/mL, methanol is .71 g/mL, and castor and Klotz synthetic are around .97-.99
g/mL.
Old 08-12-2014, 12:35 PM
  #5  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by rcbence View Post
So I have an HPI savage 4.6 and firestorm. Bought a case if werks racing fuel last year. Both my 4.6 and g3.0 didn't last over 1 1/2 gallons.

I broke them in on the fuel using HPI idle method then running them after. Never let the temps get lower than 200f.

Engines didn't last. Sure I had some lean runs not being aware of the oil content. I'm sure I reduced the life instantly every lean run.
Never could get a solid lsn tune on either engine. Honestly had better luck with traxxas 20% fuel.

Both engines sure enough had the pistons go past tdc wear mark when disassembled. Lost compression when warm and lost holding a solid tune.

I'm not blaming the fuel 100% but will no longer run a fuel with so little oil. Especially the first few tanks when the piston is mating to the sleeve.

Werks has 6% total oil with a simple evaporation test.

Measured 300cc of fuel and poured in a tall glass. Lett it sit out a day and 80% was evaporated. Finished off with a heat gun barely holding a boil and was left with just oil.
Put the oil in my Byron's lube booster measuring cup that holds up to 1 oz or 30cc.

Poured all in and got 18 cc of oil. 300cc .06 is 18cc. Simple.

I find it amazing people saying.....wow! This fuel is solo good! It just revs up and get longer run times!.

I can do that too. Here's how.

Buy nitro. Buy methanol. Buy some klotz benol.

Mix 20% nitro. 5-6% castor and rest methanol.

More energy stored means longer run times and better revs because of less oil. Simple. That's how to make a solid race fuel.

I'm sure the pure 6% castor would protect better as well than a castor/ synthetic blend at 6%.

I did test traxxas power plus too.

Guess how much?

Most say that its crappy oily fuel. Runs hot smokes a lot must have 16% oil.

Nope. Its 10% total. 200cc of fuel. 20 cc was left over.

That's right. Less oil than byron race 2000 which is 12%

I find this hilarious in fact. That traxxas has less oil than everyone thinks. Now they say its a blend....but I believe its mostly castor. The smell while burning....plus the oil that's left behind is fairly sticky.

To make sure I'm actually close to the oil percent I tested some omega I have that claims 17% oil

This one I just measure up 100cc of fuel. If there's 17cc of oil then we got 17%.

And it showed about 16.....so close enough. Might be off 1% at the most.

So traxxas has at least 10% but no more than 11% oil.

Amazing how much more oil plane engines can handle without loading up real bad at idle. Not sure why car engines just don't run as good with 18% oil. Properly tuned on low speed they load up badly at idle and never really clear out unless you stay at wot.
I believe that the recomendations by the manufacture are to get going fast and to go fast for racing. The low oil content may be fine for max speed but methanol fuel just needs more oil than gasoline. Not to mention the small size and lack of a rod bearing. So for sport you probably need about 18 to 20% oil.
Old 08-12-2014, 05:38 PM
  #6  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,054
Received 29 Likes on 29 Posts
Default

If you're a good tuner and don't race, 10-12% oil is fine really. I run 8% castor 30% nitro in my car engines though my usual brew is 20/10. I attribute the OPs usage of the break-in from the mfg. started the wearing out process. Idling for long lengths of time is the wrong way to break-in and right way for wrecking a car ABC engine. The conrod ends and the piston do not mate together with their respective parts properly unless ran at a rich high rpm setting. ABC & AAC liners need that hot and fast running cycle, especially if it's a tight engine which is critical to conrod life. Performance engines have a little more clearance between the conrod bushing and the crankpin and/or between the conrod and wristpin. High rpm keeps the conrod bushings pressed against the one side of the bushings allowing a bigger pocket of oil behind the crankpin and/or wristpin.
Old 08-12-2014, 08:31 PM
  #7  
rcbence
Thread Starter
 
Join Date: Jan 2013
Location: , OR
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks guys. After both my HPI trucks wearing out soooo fast I started wondering if 1 or 2 gallons is the norm. I agree with the break in in method being part of the problem. The 6% oil just seemed to over rev so easily if leaned a hair too much. The fuel did have good power and a bit more run time. But I'm not racing and my 20% 16% castor oil fuel has plenty of power and so much more lean protection. I do still tune on safe side of peak. I thought something was wrong when my cold pinch was gone by 2 quarts on my last piston/sleeve. Now with about the same amount of fuel in I have nice cold pinch.
Old 08-12-2014, 09:38 PM
  #8  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,054
Received 29 Likes on 29 Posts
Default

Pinch and compression are two different things. The pinch goes away when the engine is at its peak power production essentially. What I mean is with the plug out, you should not get "stuck" at TDC but roll through TDC only noting a slight snugness.
Old 08-24-2014, 12:19 PM
  #9  
rcbence
Thread Starter
 
Join Date: Jan 2013
Location: , OR
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Default

So let's say there's zero snugness. Isn't it only gonna get worse as it warms up? Or maybe the piston expands slightly as well to get that perfect seal.

Why does an lrp for example have a much longer lasting cold mechanical pinch?
Is that something you want to go away for the most part.

My lrp has crazy mechanical pinch at over 2 quarts now.

My g3.0 has a bit of snugness with close to the same fuel thru it. So it seems to have seated much faster.
Old 08-24-2014, 04:55 PM
  #10  
1QwkSport2.5r
 
1QwkSport2.5r's Avatar
 
Join Date: Oct 2006
Location: Cottage Grove, MN
Posts: 10,054
Received 29 Likes on 29 Posts
Default

The tighter an engine is when new generally means it will last longer provided you run it in right. When the mechanical pinch goes away, it will have already started to lose power.
Old 03-09-2015, 11:07 AM
  #11  
Fuelman
My Feedback: (6)
 
Join Date: Dec 2001
Location: Jordan, NY
Posts: 1,109
Likes: 0
Received 3 Likes on 3 Posts
Default

Breaking in any two stroke ABC, ABL or AAC engine, which has a tapered bore sleeve requires a hot break in. What I mean by hot is; operating it at design operating temps. The bubbly rich idle method which a lot of car engine manufacturers recommend is detrimental to their longevity. Using a low oil content fuel only magnifies the issue.

Using low oil fuel, like the 6 percent you mention has multiple effects. First you are running it at leaner needle settings since there is more fuel per induction stroke than there would be in a higher oil fuel, say 14-16 percent. Second, the greater methanol content (in a low oil fuel) has a greater cooling effect as it vaporizes, making it a little more difficult to get to optimum operating temps where the top of the sleeve expands to a near zero clearance with the piston. At these near zero clearances, the oil is critical to keep the piston and sleeve from scuffing, and since you are running it at leaner needle settings in the first place and have a low oil content to begin with, it is a very tricky balance to keep the engine operating in its sweet spot without accelerating the wear.

We have not even talked about the effect of low oil content and leaner needle settings on the crank pin or connecting rod wear.........

I had a couple test buggy's, Losi XXX NT's that I had stock engines last 20 gallons. To be fair, I broke them in, completely differently than what the instructions suggested and routinely ran high oil content fuels like I would for two stroke airplanes in them, and tuned them to the fuel, plug and weather conditions/ temperatures instead of using a digital temp meter.
There is way too much miss information out there propagated by the RC car manufacturers.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.