Alex-7

It just turned 100mi on the new motor so I really shouldn't be reving it that high but today I couldn't resist.
After putting around for the last couple of weeks with the ocasional roll on up to about 4.5k I had started to come to the terms with the fact that my car did'nt really feel all that fast, maybee kinda quick, but definatley not fast. So today I decided to see if my secondaries where opening (it's a six port 13B with the RB Holley 600 carb) so I did the 'ol screw through the linkage to make them mechanical trick, took it for a spin and OMFG! it felt better. Before it would just flatten out above 4k, now it pulls like crazy after 3,500. I can't wait to get it profesionally tuned, hopefully they can get rid of this lurchey stumbling **** down low and maybee find a few more HP (I think it's running really rich)

I guess my question would be, why do you suppose my secondaries are not working off vacume? I bought a vacume secondaries carb to have vacume secondaries.

I am yet to hear of anyone running the Racing beat six port setup without converting to mechanical seconds.
Racing beat even told me that they wher having this problem with 50-75 % of their kits and "havent figured out what to do about it yet".......WTF

Sorry about the BLAH BLAH BLAH
-- Alex

gonzz

What jets are you runnning? How do they tune it? Wideband?

mmasid

If vac secondaries aren't opening then either they're stuck or there's not enough vacuum or bad linkage.

hotty

ONLY to 5500rpm? **** son, I hit that daily, and my 7 has 292xxx ORIGINAL kms on the SE. (180k+ miles) for u states peeps. I'd say you have to rag on your car a few times to get the carbon out a bit more. It doesnt hurt your car to rev it now and then My car loves 7,000
Daryl

Illswyn

new motor with 100 miles on it. He's going easy on it.

What reason did they give you to go easy on it?

Alex-7

[QUOTE][i]Originally posted by Illswyn
What reason did they give you to go easy on it?QUOTE]

None, I just figured I should get at least 500mi on it and change the oil before I take it too high.

I don't know what jets I have, this is my first Holley and I still have a lot to learn about it. I was going to buy one of those jet asortments and play around with them because i have a ported motor and the carb is set up for a stock port, but it seems to be geting enough fuel as is.

If anybody has any info on racing beats fix for this secondaries problem please let me know.

thanks for the replies,

-- Alex

hotty

oh **** sorry.. i should read better.. I thought you meant 100,000 miles ... *** i must be blind.
Daryl

Illswyn

I guess what I'm saying is, why 500 miles? make sure it's clean after the rebuild (it is a rebuild right?)? Why not 50 miles...get that crap out if there is any. 50 miles is more than an hour of that stuff (if there is any) in your engine, and it needs removed, right?

My concern I guess, is what would the reasoning be behind going easy on it. I may be having a rebuild done soon, it'd be nice to have more opinions on it.

I know with piston engines people baby them as well, to seat the piston rings. But then I read on (www.mototuneusa.com) that babying it won't be better for it, it'd be worse. Being that that guy builds racing motorcycle engines, I'd take his word over a backyard mechanic re-quoting what he was told by another backyard mechanic. But that's pistons, not rotors.

fatboy7

Next time you rebuild, go ahead and beat on it in 50 miles, you'll never notice or miss the extra horsepower.

Fact is, beating on the motor before the apex seals seat will cause them to scuff and chatter, accelerating wear and limiting compression. And its especially true on used housings. Almost all rotary builders, including Mazda, says to keep the load light (no WOT), and the RPM's low (<4k) for 500 miles, then slowly increase the RPM's and load for another 500 miles. Some say that compression continues to rise until almost 3k miles.

Illswyn

All I'm asking is, is there any contradictory advice as well, as there is with piston engines? Some say baby it, others recommend basically putting stress on the engine, forcing the piston rings to seat quicker, and seal better.

I think instinctively I would want to baby it as well. But that's from years of hearing that advice as well.

Do race engines get driven easy for 500 miles before being put out on the track? I know they're more precisely built, but I think the same concept would apply as far as seating rings or apex seals.

rxtasy3

iTrader: (2)

race engines r usually broken in on a dyno. i've always been told to keep it under 4k for the first 1000 miles, this rule has always worked for me. i have almost 9k since i rebuilt mine.

twigg

im sorry, but i couldnt help but laught, not to be mean, but A ROTARY LOVES high RPMS if not abused, ever had a lot of snot in ur nose, imagine letting it build up and never breathing out hard to blow it out! Bringing it to 7000 RPM every other time or other isnt going todo any damage 98% of the time, unless you have other SERIOUS problems, else eh =\ ihave 95,000 miles on my rex and ill take it up to 8000 RPM in 2nd gear, i change my oil every 2 1/2 weeks, and allways use a full can of marvel mystery oil. Driving below 4.5k all the time would accually be bad for it in the long run in my opinion.. did this all make sence cuz im kinda baked, but i know my rotary

Blow out y0 carbon!

Marvel Myster Oil Cures many carbon caused health issues says the rotary surg general.

twigg

and also didnt add ive taken new motors all the time with marvel in them on 400 mile engines and pssh, hit 7k rpm, drop the clutch, spin a donut then take off, maybe im a idiot, but its never cause problems....

Alex-7

Thanks twigg, I hadn't thought of it like that.


-- Alex

Tom

When I bought a 13B SP from Rotary Reliability and Racing some years back, Nick VanNugteren was very specific in stating to keep the revs below 4K for the first 300-500 miles, vary your engine speed within that range, and change the oil and filter when done.

BigJim

i Got my new Engine from Atkins, and they along with all the other places i looked recommended taking it easy for at least hte first 500 miles. My engine didnt go above 4k for the first 500, then it went to 5k once in awhile. Not till 1k miles did i open mine up. It may be a little longer than needed, but rather safe than sorry. My engine will last awhile i hope

fatboy7

Like I said, Beating on a new motor may not cause noticable problems, but you could have just stunted it's development.

Its just like a a child who at the age of 14 who does something stupied and stunts his growth. He'll never even know that he should have grown an extra inch or two.

Illswyn

I think my question though is...WHY.

Why does it need to stay under 4k. What does it accomplish.

If you read that site I listed, it's interesting, although geared almost entirely toward motorcycle engines. But a motorcycle engine is still composed of the same kinds of material, correct? Piston rings "seat" similarly to how apex seals "seat," correct?

His contention is that manufacturers have several reasons they want you to go easy on the engine.
#1 being related to motorcycles, what happens if some new rider winds out gears 1, 2, and 3? He's going 100+ mph, on a bike he's never ridden before. That would be bad news, eh? What about warranties? They'd rather tell you that adding oil occasionally is normal, and expected. And people accept that.

I'm not saying he's 100% correct. But what I am saying is, it works for him, it works for others, and interestingly enough, he has a picture of some Japanese motorcycle factory line where they have the motorcycles being revved high. IN THE FACTORY! Why? Possibly to do what they're afraid of letting the consumer do, seat the rings by warming then revving the engine appropriately.

Anyhow...just a thought for discussion as it's related to breaking in a new/rebuilt engine. Seems to me that any flaws from the factory should be known sooner rather than later, and babying it covers them up.

Tom

Here is something interesting from Mazda Motorsports (cut-n-paste job):

FROM MAZDA MOTORSPORTS RE ROTARY ENGINES:
A proper and careful break-in period for a newly rebuilt engine is extremely important. The break-in procedures listed on the following page may seem excessive; however, an engine tha has been broken in properly will see more power across the engine’s rpm range and longer service life than a comparable engine that has not._ If using the old bearings, pleas note the difference in hours and mileage requirements for the break-in period.

When breaking in any engine (race or stock), use a low ash content, mineral based racing oil (20w or 30w). After the break-in period, change to a mineral or synthetic racing oil (30w or 40w).

RACE ENGINE BREAK-IN
Using a dynamometer for engine break-in is preferred._ If you do not have access to a “dyno”, use the mileage break-in figures on the next page._

The engine should first be run at idle for 30-45 minutes._ During this time, be sure to check for leaks and keep an eye on the gauges._ Ideally, for the first 100 miles (depending on use of new or used bearings), avoid operating the engine above 5000 rpm or under heavy load.

From 100-200 miles, gradually increase rpm, but never allow the engine to approach red line._ Beyond 200 miles, we recommend only short bursts of power approaching red line for 100 miles._ At this point, change the break-in engine oil._ The engine break-in period is now complete.




_

Jeff20B

iTrader: (13)

With new bearings (or swapped rotors and/or stationary gears), some bearing material will wear and go into the oil filter. If the filter bypasses, bearing material will go back into the bearings. Not a good thing to have happen.

Breaking in an engine is such tedious work.

Illswyn

But Jeff...that bearing material will go into the oil whether you rev it at 500 rpm, or 5,000 rpm, will it not? And just how much material do you expect to uh...scrape? off of the bearing? Will that material be any worse for the engine at idle than at say, 7,000 rpms? Or will it do damage either way?

Aren't bearings made to pretty exact specification? Then why would they normally wear? Why not machine them to the specs of where it would wear to, and avoid the wear process? I would think any wear should only occur if there was a mistake in the build, which you would want to identify as soon as possible.

Again... I'm just trying to understand the concept behind it.

fatboy7

Friction losses in apex seals rise quadratically with RPM, and linearly for side seals. That means that the heat disipated in the apex seals at 5656 rpm the heat is double, and at 6928 it's triple the heat disipated at 4000 rpm. Keeping the revs low until the apex seals seat on the hard crome surface keeps them from overheating. Once they've seated their friction coefficient drops and they can handle higher RPMs without trouble. If you overheat the apex seals in the break-in period, they scuff themselves and scar the housings. Eventually they may start to chatter because of the poor seat, but in the least they'll never seal as well.

Apex seals and piston rings are only similar in the function they perform. First, apex seals have a rounded sealing surface, not a flat one like piston rings. That means that the sealing surface is much smaller (almost a line), and that it shifts from one side of the round surface to the other as it goes through a cycle. Second the housing is coated in hard chrome, not honed steel, and often it's used, so it already has worked in wear marks. New rotor housings have that teflon lining that Mazda developed in '86 that helps the break-in of apex seals, I guessing that as far as apex seals are conserned you can shorten the break-in considerably with new housings.

bearing wear will be minimal, but there still will be material from somewhere that ends up in the oil pan, its just a fact of life. At higher RPMs there is a small but present possiblity that the filter, which is quickly filling up with this magic material from the build, will start to bypass, and that magic material will end up taking a second trip through the engine.... bad mojo

Jeff20B

iTrader: (13)

That's a good explanaition. I also should have said keeping the RPMs low during engine break in is tedious work.

Tom

Oh man is it tedious! I remember when I was just about at 500 miles on my SP 13B.. My wife was following me in case I broke down or needed help. We were driving on a road on South Mountain around evening time.. Coming down the other side I hit 501 miles and cracked it! Ran for about a 1/2 - 3/4 mile WOT!
I pulled over on the shoulder to let my wife catch-up.. I was all plastered with a ****-eating grin when she pulled up.. My wife was like "Are you OKAY!! My God I thought the car exploded!"
I was like- "What in the hell are you talking about, woman?"
She said- "When you were at the bottom of the mountain, I saw a HUGE ball of fire streaming behind the car! I thought you blew up!"

It was the 'fireball' after decel..It must've been huge! I was like "Oh ****!- that is way too cool!!"

Jeff20B

iTrader: (13)

Heh, that's cool!