bkm_rx7

i had the 7 runnin for about an hour last night. I put your carb on there ryan (holley 465cfm) and its still got the same issue. It ran a bit better with your carb on it, considering it was able to run at about 2300rpms. i set the idle and let it run for about 15 minutes to begin with, it sounded like it was running quite a bit better, and we were able to put a timing light on it, but forgot which mark was TDC. Anyways, since it was sounding pretty good while running at 2300rpms, i decided id turn the idle down to see if itd go lower after about 15 minutes of running. Well, once it got below about 1900rpms, it died. Im *hoping* this is a jetting/timing issue. I say jetting again because i pulled this carb off of my brothers 13b (most likely streetported).

Anyhow, i got real pissed because after those 15 minutes of running, it would not even try to fire. The car didnt seem flooded (i pulled the plugs and they lookd fine) and i just cannot understand why it will not turn over after its been running.

So i go take a shower and come back 20 minutes later and with a little bit (about a capful) of oil in the carb, she fired right up. WTF?! Why is it that when i let it sit for a bit like that it will start up relatively easy, yet after its been running it wont even give a puff like its trying to crank over?

Oh, and after about 2 sleepless hours and finally deciding i need to find out what my compression is, i got to thinking about how i did my ports. Are there certain irons that i am supposed to port on a 1/2 bridge that will make my car idle at low rpms? For example, it seems to me (after thinking about it logically) that the two outer plates would be the ones that i would want to bridgeport, because those intakes are connected to the secondaries on the carb, am i correct? If so, ****! Because i streetported the outer plates and bridgeported my intermediate housing (so if i messed up either BP, id only mess up 1 housing...

Finally, id like somebody to take another look at my ports on my cardomain page (click sig) and tell me, according to the ports and which irons i ported and how, if my car should have high idle issues like ive described.

bkm_rx7

PREVIOUS THREADS:

The woes continue...

1/2 BRIDGEPORT STILL WONT START! (close to giving up, help me please)

ITS ALIVE...kinda (help with 1/2bp 12a holley 600)

85rotarypower

Well, first of all, I'd check your compression if I was you. I looked at your port job and its not too bad. But your irons looked scratched and pitted. This could lead to low compression.

As for the 1/2 bridge, ya, normally you bridge the secondary ports not the primary, so this could be the cause of your idle problems.

BTW, the jetting of the carb doesn't really make a difference below 2000 rpm, at least from my readings.

bkm_rx7

I agree with checking my compression, im gonna go buy a tester (or borrow) after school today. Also...****! So now i dont get the power of a full BP, yet i get the shitty idle...YEAY! <---- extreme sarcasm

Well, at least i know how things stand right now, i guess ill be idleing at around 2000rpms. Also, im glad i have another engine i can tear apart, because it looks like im just gonna go with a SP on this next one...damn you "gas shortage"!

bkm_rx7

UGH! i just went back and looked at the pictures of my ports...they are on the correct housings! WTF is the problem?!?! Im willing to pay somebody if they wanna come fix my car...PM me if you are near colfax, washington and think you can help...im DUMBFOUNDED at this whole mess...its really starting to get to me...

Jeff20B

iTrader: (13)

If it starts easily with a little oil poured down the carb, your starter is likely too slow. How fast does it crank? You want a quick rerererer. Not a rorororor (heh, can you imagine what that sounds like?). Even a starter that would start an older engine may not be enough for a half bridged recently rebuilt engine.

cdrad51

sounds more like a low compression problem if you ask me. Then again, nobody asked me.

Jeff20B

iTrader: (13)

Yeah, but there's nothing he can do about that without a rebuild and some different plates. I think karism had a similar problem with his really big ports. The best advice is to get a fast cranking starter or a supercharger.

jays83gsl

Brenden, my best right now is to step away from the car COMPLETELY for a couple days, or even weeks.

When MY car was being a complete idiot like this, I did the same thing (paying attention to the 323) and came back with a fresh head on it. After that, I found the problem (something stupid that I can't remember) almost immediately.

Keep it up

Kentetsu

Have you verified that you are still getting spark after it shutsdown when hot? I'm just wondering if maybe your coils are loosing it when they warm up. It's a longshot, I know...

As far as compression goes, it seems that it would get better when the engine was warmed up. So why can you start it cold but not hot? I keep coming back to inconsistent spark. Just a thought...

Eatdust

I'd hate to say it..... The first sign of a nutted engine is that it is hard to start when hot....

Anyway....except for mechanical woes (read engine stuffed) you can only have two or three major issues. There is either a problem with the fuel system, a problem with the ignition, or maybe something like a vacuum leak...

I once had a car which would start and run for a while at about 2k rpm but wouldn't idle. It would slowly die, then I would be unable to start it for say 10 minutes. It turned out that the fuel pump had packed it in, and once replaced with a carter gold it ran great.

What about earthing on the motor, can cause electrical problems, if not enough.

But if it was me I would get a good mechanic to look at it, just pay for it so that you can get some sleep! They may see a problem just by looking at it As the old saying goes an eye full is better than an ear full.

bkm_rx7

the fellas that told me over and over again that it was low compression were right, even tho i repeatedly denied it...

Front Rotor - 55psi
Rear Rotor - 35psi

i just dont get how that engines compression could be so frickin low...

also...those numbers i got from a piston compression tester...so those are the high readings...

d0 Luck

welps, that's a rotary for ya

mcnannay

hey do you guys think using new apex seals would help compression that much?

i looked at the housings and they looked really good, some of the best used rotor housings i have ever seen, but he did re-use the apex seals. Im wondering if new apex seals would really make that much difference.

bkm_rx7

why are you on this forum...or in my thread even...go talk **** about rotaries in places that care or share your opinion.

Ryan (mcnannay), i totally agree with what you said, my housings were in incredibly good shape and my irons didnt *seem* that bad. Although, maybe they were really bad.

I think im gonna go take out all my frustration on the motor i pulled from my car...i wanna know what an engine i know used to run looks like...

also...im really frickin disheartened by all of this...all that time, money, effort, porting, for nothing...i feel so shitty...

gsl-se addict

iTrader: (3)

I wouldn't worry too much yet. Try to get it running again and just let it run awhile. This will help seat the seals. Even if you did use new apex seals, I don't think it would help that much as the housings are used. It is going to take some time for the apex seals to wear into the grooves of the housing. In addition, large ports will reduce the compression reading, so don't expect the numbers to be the same as a stock port. They are a bit low, but there is no harm in running it longer to try to increase the compression before deciding to tear it back apart.

Even on my stock port, it was hard to get running after I tore it down. It didn't have many miles on the motor (rebuild) but did have carbon lock. I used real good used housings, used apex seals, and basically cleaned everything up and replaced the soft seals. After letting it idle for long periods and taking it for some drives, it started easy as the compression began to climb.

So don't give up yet. Fire it up let it run for 30 min to 1 hour at a time. If you can't get the idle below 2500 or whatever, just run it where it will keep running. As the seals seat into place, it will run better, start easier, and idle at a lower rpm.

Kent

Hades12

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
What he Said.




You may want to Look for Judge Ito over on NP or hunt for him on the Old Rotory Board.

bkm_rx7

Well...how long do you think this will take? I have very little power and am scared to drive it anywhere bcuz if i kill it or shut it off, i might not be able to get it started again! But i have had it running for about 30-60mins about 3-4 times now, and my compression is TERRIBLE!!!

Is this normal?

85rotarypower

Well, I ran into the same problem with my 13B when I installed it. Its fuel injected, but it ran like ****. The idle would go up and down real slow between 1400-2000 rpm, and was only running on one rotor below 3000 rpm. Turned out the compression was bad, even tho I kept insisting it wasn't. Oh well, thats what I get for buying a used engine without first checking the compression. To be exact, the compression numbers were something like 55 psi rear and 65-70 psi front. Rear rotor would not run below 3000 rpm, and car was VERY hard to start and would not run below 1200 rpm.

As for your problem, try breaking it in a little, but with the amount of run time you have on it, I would say it should be starting to make good compression. I don't know from experience or anything though. Never dealt with breaking in a rotary before.

d0 Luck

take a chill pill man. you don't hint the 'obvious' sarcasm?

here's my .02 cents for ya then.
recently built motor w/ less than 300-500 miles will ALWAYS hvae low c/r.

one technique that could and should work is, letting it idle for 1 complete hour. even then, motor will still have much lower c/r than usual, but it's a safe and cheap insurance.

keep on trying letting it idle itself for 1 non stop hour. if you built your motor within spec tolerances, then it should be fine. either that or you 'messed' something up during the rebuilt.

gsl-se addict

iTrader: (3)

It is really hard to say what is normal or not with used parts. They were from different engines I suspect. With new parts, it would probably be pretty well seated after 30min to 1hour of idleing. With mine, I ran for several hours total before driving it. I had other things to do on the car, so I would go out and fire up the engine and work on other things (interior) or eat lunch or something while the car was running. I think it will probably seat faster once you are able to drive it, but you want it to be running pretty good before you do that so you don't get stranded (or have some one follow with a truck in case you need to be towed back).

From what I have read it is the heat cycles that are important. This means that it will break in better running 8 times at 30 min each (with cool down in between) instead of just running 4 hours continuous.

Kevin Landers has a pretty good description of the break in process (in the tech section).
http://rotaryresurrection.com/

You will have the idle at a higher rpm than what is stated on his site because of your large ports.

Also, starting and compression depend on cranking speed. So if your battery is a bit low, terminals are dirty, have bad battery cables, etc, this will lead to poor compression readings/hard to start.

Also make sure timing/ignition system are in good shape.

You may want to buy or borrow a manifold vac gauge. This will give you an idea of how well everything is adjusted/or broken in. The manifold vac should improve as the seals seat into place. Also the vac gauge is helpful in setting idle mixture (adjust to get the best vacuum at the idle speed that you want). As the manifold vac improves, you will be able to drop the idle down.

Just keep going with it. Don't give up. I know it can be frustrating (I was in the same spot). I bet with time, everything will seat into place and you'll have a monster on your hands .

Good luck.

Kent

bkm_rx7

heh...sorry...i knew it was sarcasm...but i was in a really bad mood. The car is running right now...will be for another 30mins or so.

funny thing is...i did give up on it earlier today...until i just got these last few posts...i tore down my old engine tonight...dear god are the rotor housings bad! there is a spot on one of the housings where a good 1inch X 1inch chunk of chrome is chipped off

i guess if nothing else...ill have another backup engine...

*edit* - by "running right now" i meant "car is running at this point in time" not running correctly.

Elysian

this is what i'm wondering... were ur rotors clearanced at all? how easy were the apex seals to move in all the grooves? if it was a tight fit ur apex seals might be sticking... but i don't know... just my guess... as for your idle issue... my 7 idles at 1.8k now... after i finally got it running, with the holley 600 cfm i got on it... i can't get it any lower than that, but it runs great, and i'm real happy with it... takes a bit of cranking to start, and mines not even a bridge port, just a street ported 6 port... i've not had to pour oil down the carb to start it tho... i think used seals can make a huge difference, and depending how clean the grooves for the seals were might effect ur compression like that... good luck with it whatever you do, i wish i could help more, but ur quite a ways away from me...

karism

Did you get the jet kit yet?

Jeff20b ,and GSL-se addict is right about the cranking speed,and vacuum.

I had the same problem with my bridge,some questions helped me solve it.

I`am going to ask some questions,please answer all of them,so we can help you solve this

Let me ask the obvious:
1How old is your battery?
2Is it properly charged before attempting to start it?
3Is it a large/factory sized battery,or a small one?
4What plugs do you have in?
5Are all the plugs even coloured?Or is the front/rear rotor darker or lighter?
6Did you replace all the hard seals in the locations they came out of?

Karis

trochoid

iTrader: (6)

I tend to agree with most of the recent posts.

You used used seals, that didn't come with the housings you are using, nor are they even in the same place they were in the previous engine. The apex seals have thier own wear pattern that doesn't match the current housings. Give the engine some time to wear in to itself. You will probably see the compression come up after a while.

Don't feel bad, you heard the vid of my bp, sounded mean, until I put the rest of the exhaust system on. Now it sounds like ***. Need to get a 3" system built. The oem muffler is a pos.

When I did this rebuild, my first, I only bought the minimal seal kit along with corner seals and springs. I should have replaced the oil control seals. It smokes like I just did the atf treatment!!!! So I may be pulling mine and going through it again, but with a full seal kit this time.

Am I disappointed, not in the least. This was my test engine. It starts up quickly. It will idle at 800 rpm if I want to turn it down that low, (idles better at 1k), and when I get the rest of the car put together, I get to take it out and abuse it. It will probably hit the 1/8th mile drag strip before it has 100 mi. on it.

Once I have the engine tuned and can take it out to the strip, my expectation will have been met. (Goal is to get under 9.3 sec., that beats my friends TII) If I can get the smoking reduced and the engine lasts through the summer, I will have exceeded my original goals. Then I can spend the money for parts for a full rebuild, or bite the bullit and start buying the supporting mods for the spare TII setup I have sitting around.

Take a break if you need too, sometimes one can come back with a fresh view point. Things will look better. When I get to the point you've been at, I find something else to do on the car, or go park myself here and learn more.