If the car is running but just very rough, whats a good sign that it has a blown rotor or apex seal?

 

you can floor it in neutral and it takes like 5 seconds just to get to 6k... also it will sound like a lawnmower and spit and pop constantly out the exhaust whenever you put load on the engine... and you have to drive full throttle just to go 50mph in 4th, and it takes a week to ten days to get up that fast.

But it will still run Rather have that happen than blow a rod out the engine block and have to call a tow truck 'cos the engine locked up... (no wait I have driven a 429 with a rod hanging out the side for a little while... )

 

If u don't have a regular compression tester. borrow one. Take your Trailing spark plugs off and put the tester in, disconnect your crank angle sensor and crank the engine. Try this on both rotor housings, if u get no compression reading from one rotor housing u have a broken Apex seal Sometimes when u have a very clogged catalyc converter your going to have poor acceleration and no power, with the compression reading u go straight to the heart and check it's vital condition. If both rotor housings check ok for compression then u have a good engine and need to check elsewhere.

 

So its that dramatic when a Tip goes? No power at all, very hard to drive and does alot of poping and banging?

 

The apex groove in the rotor wore out and my apex seal eventually fell out enough to lock the engine up. I ran it low compression for 3 years. Probably 15,000 miles total before it locked up. It was hard to start sometimes and idled a little rough but nothing to bad.

 

You'll notice an increase in noise once you lose an apex seal. Your cat is likely to start backfiring a lot more since you're passes raw gas out the pipe and the cat will detonate it.

 

It does it even with no emissions equipment! Trust me I know firsthand now!

And it gets even louder once your blowtorch of an exhaust burns out the muffler... and I had a heavy duty stainless steel muffler!

 

It seems like the symptoms of having a bad rotor and the symptoms of having fouling plugs are similiar no?

 

If the engine is trying to shake itself out of the engine bay, its cactus.

 

I had some touble checking compression on my rotary, since it's my first. Check compression at WOT, look for three even bounces. If you have trashed an apex, you'll see one high bounce, two low ones. When you lose an apex, you lose compression on the rotor faces on each side of the bad seal.

Gregg

 

I can say the best way off telling your tips are on the way out is Comp Test but the biggest symtom i had is it would'nt start properly, mine was not dramaticly worn.

 

If you dont have a compression tester, pull the plugs out of one rotor and kick the motor over. There will be 3 even...um..noises? When I did my engine lst time we did this to see what is was doing and it sort of sounded like:

chssssssssh - chssssssssssh - pffffffffffffffft

You will tell straight away

 

When you take the engine apart and it looks like the link in my signature, that's the most accurate way to tell

My '87 has a blown seal on the rear rotor, but the other two are still good, when you crank it over with both leading plugs out it sounds like
puh-puh-puh-()-puh-()
- 1 -- 2 -- 1 - 2 - 1 - 2

you can see, rotor #1 always has compression, while since #2 has one blown apex seal, that compromises the compression on two rotor faces, so it only has compression on one rotor face.

If two apex seals are blown on a rotor, you'll have no compression at all because all rotor faces are compromised. Likewise, if the apes seal breaks up and exits the rotor groove and decides to demolish the rotor housing, even if the other two seals are still good, they won't make good contact and you'll have no compression for that rotor. Either way, you'll have even-sounding compression, so the only way to be really sure is to only test one rotor at a time.

Generally though if it suddenly runs like utter crap and doesn't get better after letting off (fuel starvation) or flooring it a while (fouled plugs) then you've most likely lost a rotor.

 

well, the easiet way if you've blow a seal, if you have a boost gauge, is low vacuum. Lower than it was before, in the 10 to 12 range or lower. engine rocks back and forth. what vacuum are you seeing?

Tim Benton

 

 

that sounds like my engine when it had 125psi compression... i think it was like 8 inches of vacuum at idle sometimes...

 

Like that one did you Ito?

It was weird because the apex seals were fine, it was just the side seals that had gone AWOL!!

 

Hmmm... that is actually the best way to check... you can also pull the piping off the throttle body and pull the plug wires, open the throttle body up and listen while sombody cranks the engine, you will hear a Suck, Suck, Phhhhh... basicly if the pulses arn't even and sounding the same you have a bad seal and the engine is D.E.A.D.....

 

Well now my problem is that it won't start. I thought it was just flooded, but I've tried to unflood it twice now. Can't seem to start it. Next step is new set of plugs and plug wires. It will turn over a little bit but almost impossible to keep it running. And yes it sounds like the motor is about to jump out the bay.

 

Ported Turbo Engines also produce low vacuum.

 

Not that low. Most ported engines are in the 14.5 to 15 range, with a stock engine being anywhere from 15 to 18 on a FD. Anything lower and your running to big a port for the street or your lost a seal. If your seeing 10 or less on a ported engine, then you just need to start saving some money for a new engine.

If you get it to start, try to se what the idle vacuum is.


Tim Benton

 

who did your ported engine work? Just curious.
You going to make it saturday, car or not?
Tim Benton

 

Pettit did the port work about 30,000 miles ago. This whole thing started when I was warming up the car one morning and when I came back out later tha car was off. I tried to start it and it wouldn't start. I did the unflood precedure and it started but idled like hell. Eventually it just shut off, th4en I couldn't start it again. Can the car be running and still be flooded? could this be an electrical problem like my coils or my Crane HI6?

 

DUDE THE EXACT SAME THING HAPPENED TO ME,ONLY IT HAPPENED DEC.23 AND MY CARS STILL NOT RUNNING!!!!
So far I've heard,try the atf trick,its flooded,the seals are bad,the plugs are fouled,or the alternators dead. I pulled my plugs checked 'em,yup,they look pretty fouled to me,top left and bottom right plug come out wet w/gas.I did the chiltons voltage test on my alternator and got a reading of 10.97,thats another suspect.The flooding is obvious,but I've un-flooded it a few times and thats when she almost started.
You say it started and idled like hell,u mean idling around 250-500rpms? Cuz thats what mine did and as soon as I let out the clutch it shut off,like the engine didnt have enough power to stay on w/the clutch out.

LOOKS LIKE WE'RE IN THIS TOGETHER!!! IF I FIND ANYTHING OUT I'LL SHOOT U A PM,I'DE APPRECIATE IT IF U COULD DO THE SAME FOR ME!!

 

No matter how much I unflood it when I pull the plugs they're soaked w/ fuel. I remember about 2-3 weeks before this all happened I was just letting the car warm up and it started to run like ****. So I got in it a drove it around the block and the idle fixed it self. I wonder if that had anything to do w/ it?