What did you engine do when you blew it?

I had a terrible boost spike today, not sure why yet but it knocked, blew a puff of black smoke and went on down the road okay.

took it home cause I was scared and wanted to look at everything and it idle very very bad. Like erratic, down to 2000 rpm and jump to 3000, back to 2000, up to 3000 and so on and so on.

Seems alot like a bad vacuum leak, the boost spike did blow off the hose on the intake nipple for the boost gauge, I had not secured it properly. I put it back on, no difference.

So what happened when you guys blew your engines, I know of two out there broke_apex_seal and officer_farva.

Please guys I need advice! thanks

Chris

 

When I popped my Turbo II,lumpy idle was the main symptom until I performed a compression test.

 

that was what i was scared of, where do I get a compression tester, i really don't think she will drive the 30 miles to the mazda dealer at this point.

 

Your not expecting the dealer to replace the engine under warrenty are you?

 

of course not, voided my warranty with only 10,000 miles on it. thats not the issue.

 

Based on posts and pictures of blown RX-8's,continuing to run may cause even more damage,on the other hand running 35 miles may not make a difference.You can get a fair idea just by pulling the top spark plug and listening to the compressed air escaping(if there is big damage.
Just as a matter of curiousity,was the boost sensor for your E-manage or whatever on the same line as your boost gauge?

 

how will it sound, the compressed air if it is bad? double boost gauges, one defi bf connected to one nipple and the protec connected to the other.

 

Zoom - How'd you manage to void the warranty at 10k? With the Greddy?

 

If you have a broken seal,the amount of air expelled for 2 faces of the rotor are significantly less than than normal.Hence less of a 'whoosh'sound.

 

mine went crunch clank clank clank stop

 

dam talk about a headache.

 

yea, voided with greddy.

I am pretty sure I have a busted seal, I had the smell of something burning and the idle is so erratic it all happen very suddenly.

I may try to listen to the compression but I don't have anything to gauge it on so I dunno. Bought a compression tester, the rx 7 guys said I just had to remove the check valve to make it work on a rotary, so I made do that tomorrow. But i think i will be on the phone with the local rotary guru monday.

I am a do it yourself guy, done everything so far and am comteplating re-building the engine if needed myself. Anyone know any good books or sites on rebuilding a renesis or is it too early for that?

 

Do you think it has something to do with that turbo upgrade you just got finished with?

 

Did you increase the boost on the E-01? Also, were you running the same emanage map for the upgraded turbo that you were for the regular greddy turbo?

 

Go to the web site below and order the DVD: "Overhauling Mazda 13B", by Bruce Turrentine. It deals with the earlier RX-7 13B's, but I suspect it will be one of your best resources for doing a rebuild.

http://www.rotaryaviation.com

 

No had nothing to do with the upgraded turbo. The protec was not working right for some reason, I was thinking that maybe I had a leak in one of the hoses and had not had a chance to change them out, was planning to do it on Sunday. I was taking it very easy on here cause i had had one boost spike before. I pulled out in traffic, was used to being heavy on the foot with the old turbo and just did it out of habit, big boost spike, pop, pop, pop, black smoke and then everything was fine. Turned down a side road to check it out, and the car went into limp mode and would only drive like 5 miles an hour. Pulled over, turned it off, crank it back up, it started fine and I drove home. got home, turned it off, checked everything, everything looked fine except for a burning smell, that went away, cranked it back up, very high idle, kicked down after a minute and then became erratic idle.

So nothing at all to do with the upgrade, just a boost spike which can happen with any turbo. I actually had a small boost spike with the greddy one before I had a boost controller.

Read alot on rx7club.com, those guys seem to pop lots of apex seals, i am thinking I am joining the club.

But now I am wondering about porting, etc so I may be better afterwards anyways. such is life

 

Check those coil packs...

 

which engine management were you running at the time?

 

i thought you had to get an adaptor to use a compression tester on a rotory......never tried it on a non-piston engine so let me knwo how it goes . hoe all is well with your engine...or at least not to messed up. i would not drive it even a mile if i'm not sure what is wrong with it...and probable nopt all all onc ei knwo what's wrong with it .who knows how bad you could make it by driving 30 miles...just my .02

 

I used an ordinary compression tester, no adaptors, to do a compression test. $30 at pepboys. It works fine. You have to understand that you are going to get the max of the three chambers if you use the check valve. There is not really a good way to get readings on individual chambers using this tool. Also, the published values are given vs cranking RPM. You either need to measure this with some other means, or do what I did and say f*ck it - if I'm over the minimum, I don't care. I really wanted the number for an A to B comparison if I ever get worried that I blew a seal. I wrote the numbers down and saved them for when I need them. I suppose if you removed the check valve, you could watch the needle. At 250 cranking RPM, you would get about one chamber passage per second. If you had a broken seal, I am sure that you could tell the difference.

You will also need to correct for your altitude. The 14.7 psi compressed 10:1 at sea level gives one thing, ~12 psi compressed 10:1 where I live will give you some startlingly low numbers if you don't take this into account.

The special mazda tool gives readings for each chamber, along with the RPM, and corrects for altitude. nice to be the dealer....

 

yea not driving her, got the compression checker from the auto store, hopefuly will get time tonight to remove the check valve and give it a shot.

The coils . . . never thought of that, does not make sense that they went out soon after the boost pack but hey, worth a shot, would rather it be them instead of an apex seal. Whats the best way to check them?

Running the ole emanage still by the way.

 

Look at them, the part near the electrical connector will look melted. There's a picture of where to look in this thread.

https://www.rx8club.com/mazsport-104/dyno-tune-76888/page2/

Myne were bad and caused my 8 to run like complete ****. Idled horrible, sounded bad, giving it gas would make it just about die. I thought I had a blown apex seal too.

 

thanks so much, you give me hope! I will check it tonight, just got off of work so I don't think I will have time for the compression check tonight maybe just maybe its the coils. Thanks guys!

 

just got back from the 8, check the coils does not look like the picture, does not seem to be melted anywhere.

So i cranked her up, started right up, no problem like usual. Cold idle was high around 3000, then kicked down to around 2000, ran until somewhat warmed up, maybe 3 or 4 minutes, then 1500, 2000, 1500, 2000, 1500, 2000.

Hooked up scansyler to it, had only one cel, P507 - Idle air control system higher than expected. Now, I always had that pesky air pump running after I shut down the engine cause of the problem with the emanage from the greddy kit, but lately I have not noticed that it comes on anymore. Its a long shot but do you guys think that has anything to do with it?

Thanks guys, without this forum, I would be so lost, i love this place man!

 

glad it seems like the engine is ok.

im going to throw this out. is not the gasket that you were supposed to reuse for the air pump. the greedy one was wrong????

or hose not in the right place is my next guess.

good luck

beers