A friend was driving my 81 rx-7 that has an almost new 1985 13B SE engine equipped with the Racing Beat Dellorto side draft carb mod and headers. This is usually an EFI engine. The engine stopped suddenly as though the switch were turned off and will not start. Spark and fuel OK but compression (top plugs) zero.

The oil was very low and could have run dry. 1-1/2 quarts to mark on dipstick. But, the low oil light did not come on and the engine went from normal power to quit within a second or two.

Is there anything elso that could cause sudden zero compression other than no oil? I unbolted headers in case plugged but no improvement. Tried squirting oil thru spark plug holes but still no compression. I realize that seals could burn up but I thought that this would result in a gradual power loss.

 

Perhaps you suddenly lost a seal due to low oil?

 

1.5 qts low unless the motor was being driven very hard would not blow the motor. The compression test is done at the leading plugs but still should show compression at the trailing. I would recheck your gauge.Are you hearing any whooshing sounds as you are cranking with the plugs out?
And how did you verify that you have spark and fuel?

 

I had to add 1.5 quarts to get oil to show at very bottom of dipstick so it was down at least 2.5 quarts. I don't know if the dip stick low limit is 1 or 2 quarts (liters) down. Still he had no warning light and most engines will still pump with very low oil as pump intake is near bottom of pan.

Checked spark by pulling all 4 leads and connecting a dummy plug with a 1/4 inch gap. Big fat spark on all plugs.

Pulled fuel line at carb inlet and big time flow. Also tried gas and starting fluid squirted into intake manifold. Remember, this engine has Dellorto sidedraft carbs so its hard to prime via carb inlet but I have priming holes in the intake manifold.

I also put a finger over plug hole and the pressure was almost non existent. Just a very gentle pulse felt. Squirting oil into plug holes didn't help; even tried 80 weight out of deperation.

I feel certain the almost zero compression is the problem and, of course, burnt out seals would cause this. However, before selling as scrap I want to be absolutely sure nothing else (fixible) coud cause this. The funny thing is that the engine quit suddenly as though the switch had been turned off at 60 mph.

 

Sounds like it is dead. RIP. Probably overheated also due to the lack of oil which would of shut the motor off. Usually at that time there is alot of indication of a overheat?

 

I say whip that friends ***; casue a friend who kills a mans RX is no friend, but an enemy, you know, a foe, a foe fo sho.
ps it sounds like to me he wasn't paying attention, it would have problems before just dying.

 

There was no overheat but probably just a destryed engine due to lack of oil. But before dumping at a junkyard I just wanted to be absolutely sure that nothing else that could cause zero compression. Since I have never been inside a rotray engine I was wondering if anything could block the intake which, of course, would cause no compression. It is the 6 port engine.


Also engine only has about 5000 miles since factory rebuild. Would it qualify for the $1000 core value exchange if in this condition? If I haul to junk yard I imagine they will just crush the whole car.

 

they would part it out and then crush it. if you do plan on taking it to a junk yard i ll take that Dell' orto and upper intake mani off of your hards.

 

Don't junk it. Save it. Put another motor in it. That or part it out.

 

One would need to run the engine nearly out of oil for it to fail. It's more likely it tossed a seal, perhaps from over-reving. A stuck seal is also a possibility. Do not scrap the car, there are way too many good parts that other members would happily ****** up. There are enough 'vultures' here that are looking for SE parts, lol. To make sure, do a ghetto compression test, remove one plug from each housing, one at a time, and crank the engine over, listening for 3 even pulses. Compare the front and rear rotors for any differences and post back your findings. Accelerator pedal needs to be pushed to the floor to allow for maximum air intake.

If you get 3 even pulses, clean up the plugs and see if it will restart.

Welcome to the forum and the Darkside. In my sig line is a link to the online FSMs, Sorry to hear the bad news, but don't give up yet. You may be able to sell it complete to a forum member looking for a project for more than the will ofer you. Post pics, interior and exterior.

 

Neither rotor has any compression. If I put a finger over the spark plug hole all I get is a gentle pulsing and a compression guage shows zero. The sad thing is that I have put a lot into the car as I intended to keep it for a long time and ,also, have many new parts in storage.

Since I inherited a 97 Honda Prelude this car is sort of surplus now and I really don't want to spend a lot of time/money now. I had just spent over $3000 on a re-man engine, starter, clutch, otc.

 

if you just bought a new engine, it should have some sort of warranty. was your friend driving the car when this happened or was it idling? 0psi of compression is very unlikely unless the engine swalowed a few nuts or a bolt or two. you need to run a compression test. pull the plugs after cranking and note their condition. post back your results.

 

Did your buddy ring the buzzer?


It is very odd for an engine to loose both the front and rear at the same time, and Have 0 Compression.

For 0 Compression it has to eat 4 seals,

 

Put the car in 1st gear and have it at a safe spot pointing away from a building.

See if the car will move when trying to start it. Just try it, you may find something you dont want too....

 

?

 

perhaps that your car doesn't have a clutch start switch. or that the guy standing in front of the car is going to get run over. the car will lurch foward due to the mechanical motion of the engine turning over, not the compression being good or bad. do not try and start it without the clutch being deperssed or the trans in neutral.

 

That was the purpose of the test to see if it lurks forward. With the results I am hearing it seems that something internal is broken or warped. I want to see if its Broken. No compression on both rotors is not a seal problem.

 

not a seal probelm for lost compression? what about an apex seal problem, or a side seal problem....... could very well lose compression because of those seal problems. it may be a couple of junk housings.... if something were broken internally, why wouldnt it still start? it would start and you would know something bad was afoot.

 

I think Nicholas P. is saying that maybe the E-shaft is broken at the flywheel?

 

Lost of guesses and conjectures, let's keep it simple. Pull one from one housing and crank, disabling spark and fuel first. Then do the same for the other rotor housing. If the belts turn, nothing in broken. If each plug hole emits 3 stong whooshes, it's not seals.

Do that simple test and report back, post a vid or sound clip if possible. If you don't know how to disable spark and fuel, read.

 

I agree with trochoid, post a video or sound clip if you can.

I am not trying to tear up his car or anything trochoid. I instantly remembered about the belt thing. So its good its not broken. When I helped in the mechanic shop somtimes stuff like this would happen to cars. Just random stuff like that due to lack of oil.

-nick-

 

Sisters car had 0 compression in #2 and #3, we thought the Head gasket was blown.

guess where the Cam shaft was broken.

 

I've broken a few rotary camshafts myself. LOL

 

Ha Ha,

It was a 3100 in a buick.

 

i've never seen a cam break...must have run that sucker pretty hard..