I finally got my engine back under the hood after porting and rebuilding it. I have (or had) new 2mm apex corner seal and everything was fine after first start. Engine runs smootly and the guy who rebuilt it drove about 10-20 miles before going to dyno to tune it. After a while something says BUM!! and first rotor lost its pressure. I´m so Fu**ing pissed off right now. What do you think what happened?

This happened full throttle and 10psi boost.

PS. See my sign and say whats wrong because car had ONLY 280rwhp until it blew up. If you ask me it should have been way over 300rwhp (330+ or something).

 

Engine wasn't broken in properly? 10-20 miles and then you dyno tune it? Doesn't sound like a good idea... How many miles was it until it blew up?

 

agreed. I hope you let it break-in for much longer than 10-20 miles. 1,000-2,000 would be more like it (some people even say 5,000)

 

Hey,

You need to do stick on the dyno just to get a Map into then you drive for a couple of thousand KM and it all should be fine. You never just go right out or else it will go boom.

Cheers
Chris

 

I've heard its quite bad to boost on a fresh rebiuld before it is properly broken in.

 

it had about 70k miles before rebuilt and we didnt do anything else except corner seal and porting. I´m not sure did he push all the way because I wasn´t there so I can´t say much but I agree with you that you shouldn´t push very hard with a new engine. I have to ask him what was he doing (or thinking).

But what you think of the 280rwhp with those mods?

 

Your output was low most likely due to the motor being a fresh rebuild. It takes some time before everything gets worn in and good compression is made. I know on my rebuild, I make noticablly more power now after a few thousand miles then when i first put it in.

Pat

 

How much more did you make after a few 1k miles? And how much power do you make now if I may ask?

 

WHY OH WHY did you do that!??? Break it in easy.... easy does it The worst thing you can do for a fresh engine is boost... at ALL!

 

your rebuilder needs to pay for a rebuild somewhere else!!!!! He did it not you.....

 

you should of let it break in. that is the worst thing to do. at least 3 500mile oil changes and after 1500 miles for a complete break in.

dom
88 rx7 se

 

that's not a rebuild. i mean, you can tear apart an engine and put it back together, but its not really a "rebuild." i hope i'm misunderstanding this. 'course, i'd like to also misunderstand the 10psi full throttle dyno run after 10-20 miles.

 

Dude, get your money back, and never go to that rebiulder again.

 

Well if you didn't replace apex seals then maybe something went bad in that area.

I can only guess but maybe he put the rotors in the wrong chambers so the grooves and compression wasn't up to what it use to be since the seals would have worn into the shape of that housing.

Simple stuff though.
Running a monster right after assembly like that = bad
1st get on Dyno to slowly set AFR's tuned correctly
2nd break it in
3rd then get it tuned perfect.

 

This is something wrong with the above statement.

My guess is that there are people who are ignorant about proper engine break-in in this picture.



-Ted

 

This is crazy! I can't think of anyone competent to build a rotary engine would then take it to the dyno after 20 miles of break-in and then boost to 10psi. Well, to answer your question, ignorance is what blew your motor.

 

I do not have numbers, it just pulled better and better as time progressed. I imagine (hope) i am somewheres near stock NA power levels now (for the time being).

Pat

 

Should have replaced more than just the corner seals. At the bare minimums, replace all the soft seals and the apex seals.

 

he said he had new apex seals. i didnt say it later when i quoted him earlier, but i saw it in a quote ted used and read it again (first post). still though. i dont know. either way.. a PERFECT rebuild taken to the dyno so quickly...

 

No the guy said he has (or had) new 2mm apex corner seal, one would assume he ment the corner seal, maybe even the small apex seal piece. But not the whole thing... who knows..

EIther way I agree about the break in, you need to let the seals bed in. I have heard of people who build race engine (N/A, not turbo..) who flog them hard from the day they're all torqued up with fine results.. but thats N/A, and even then I think that's a bit dubious.

 

Definetly agree...I have never heard of of anyone Boosting like It's nothing and taking It to the dyno In such a short Kilometer span...It's actually quit scary that this Is the case.

 

Hey guys, maybe we're jumping the gun here?
Maybe the engine was broken in on a engine dyno stand before it was installed?
That would make a driving break-in unnecessary?


-Ted

 

I'd guess the engine blew from improper tuning.

If you reuse the housings with new seals, you should break in the engine so everything seats together properly.