i was told that automatic transmission fluid can help bring back compression, he told me it would make the seals swell back up and i was wondering if this is true if not is there a way to bring back compression without tearing down the motor i have a 1982 generation 1 rx-7 thx!!

 

I, for one, have never heard that in my life. Even if it were to be true (which I don't see any reason as to why it would be), it would only be a temporary fix and you would need a rebuild anyway. Atop of that, when you rebuild you can port... and porting brings more power... and more power brings more fun... lol I'm sure someone else will chime in that has more experience with this whole thing, but I personally think its false information.

 

Kind of true and kind of not true

You can use ATF to help start a flooded car, The ATF coats the housing and helps the Seals seal better until it is running again where the premix or OMP can do it.

ATF also helps remove carbon, so if there is some build up making the seal "Stick" then it can help free it up.

If you have broken or eat a seal then ATF will do nothing for you.



So what problem are you seeing? Where in NC are you?

 

there are some things you can do to help compression, but you need to do a search on it. i know kentetsu said he added something that saved him from needing a rebuild. but im pretty sure the consensus now is not to use ATF.

 

One can of Seafoam + 1/8 tank of gas then drive it hard for a few miles. This will free up any sticking apex seals and restore compression as long as nothing is actually broken.

If you are sucking oil in through the oil control rings, then Lucas Heavy Duty Oil Stabilizer might work as well for you as it did me. 1 or 2 quarts in place of motor oil.

 

were can you buy seafoam at i have never actually seen it before

 

Sticking seals, due to carbon build up can reduce compression. This is the case for both the apex and side seals. Atf, Seafoam, even straight water can be used to soften/remove the carbon and allow stuck seals to regain thier full range of motion.

There has been some debate about the dangers of using atf, the consensus/facts are not in, imho. Some claim the atf degrades the oil control o-rings, making the engine smoke after the atf tratment. This may be a slight possibility, but I tend to disagree with it on 2 points.

1. Some components in the car use rubber for seals that are in long term contact with atf, i.e., the power steering pump and automatic trannys. The seals in the pump look no different than the o-rings. Thier composition may be different, I don't know.

2. A badly carboned engine, with stuck seals, allows the carbon to work it's way to the o-ring carriers. Carbon is abrasive and can cause faster wear over time.

When the treatment is done, the carbon build up that was in fact sealing the o-rings and carriers is no longer present and now the engine may smoke. Preventing this build up is good general maintinance for engine longevity. Occasional redlines and Seafoam treatments will prevent the carbon build up.

While this undesired result is possible, I still recommend decarboning an engine. If it brings the compression back, great. If it doesn't, it needed a rebuild anyway and the treatment will cleanup the internals, making bench cleaning during the rebuild much easier.

I sometimes use Seafoam directly into to the engine, inducing approximately 1/2 can of it until the engine chokes out on it. Then let the engine sit over night, allowing the Seafoam to soften the carbon. Next day I will follow up with the other 1/ 2 can, keeping the engine at moderate revs to blow out most of the carbon. After that I will follow up with straight water for a nice internal steam cleaning.

 

trochoid
i have a question for your about your feeling of the stuck seals.. im having a problem now from letting a new rebuild sit for a few moths / maby a year with out any fluids, its a 13bt, the car starts up and holds a ruff idle but theres almost no compression coming from the rear rotor and theres only about 5hrs of run time on this.
i used the water method before with this motor (b4 rebuild) and thought it was a good thing and i ended up running 5 gallons threw it in about 60 seconds and it did seem to feel alot better if i can remember rite. but your saying that it will free up stuck seals? i just want to know if this would hurt a new rebuild if i tried to run a gallon or two to free these seals up? i just really dont want to have to pull this back out and open it up again... lol

thanks

 

If you have only 5 hours of run time on a fresh rebuild, then none of the new hard seals have worn in and seated yet. What did your compression test show you? If you have 0 compression on the rear rotor, then at least 2 of the apex seals are sticking and they shouldn't be. Did you have this problem when you 1st started the rebuild or did it show up after sitting?

If it was a problem from the beginning, there may be a problem with the clearances being to tight and you may need to pull it down and re-spec the clearances. If this showed up after sitting, the run 1/2 can of Seafoam through a vacuum line directly into the engine. Try and run it in fast enough that it kills the engine, then let it sit overnight and soak. Fire it up the next day and run the rest of the Seafoam though slowly without killing the engine. If it seems to bring compression back on the rear rotor, let it run around 2000 rpm for 20-30 minutes, then do another compression test.

Unfortunately, since this is a fresh rebuild, you can't really rev the engine past 4000 rpm to try and break the stuck seals free. If it runs well enough to drive, take it out and start putting some miles on it and get it broke in. You can raise the rpm limit 1000 rpm for each 500 miles you put on the rebuild. By the time you have 1500 miles on it, you can shoot for redline, unless you replaced the bearings then you need to go 750 miles between rpm raises instead of 500.

If , by 500 miles, you still aren't getting any compression increase in the rear rotor, pull the exhaust manifold and inspect the apex seals. Push them to see if they spring in and out of the grooves and check for any chips, cracks, etc. If you can get your hands on a boroscope, check the lower part of the housing surface. It might be prudent to go ahead and do this check now and save the time and fuel in case something unforeseen, like a dropped foreign object, has made it's way into the engine.

If you have 0 compression on the rear rotor, I suspect that may be what happened. I find it hard to believe that at least 2 of the apex seals on 1 rotor stuck on a fresh rebuild.

As far as doing the water treatment, no, not on a fresh rebuild. There shouldn't be any carbon build up to make it worth while and the water will remove the premix coating that's needed for the seals to seat.

 

k i will try the seafoam tomorrow and will let you know how i made out in a few days.. thanks for the late reture tho i was thinking i mite be the only one really on this time of nite.. ttyl

 

LOL, my sleep hours are whacked I'm on anytme of the day or night. Worked on call 24/7/365 for too many years for the railroad. Even after parting from them 14 years ago, I still can't settle in to a regular sleep pattern. Trying to work a regular 8-5 'normal' job throws my system off even more.

 

well i have it soaking today and rotated it every few hours. i hope the seafoam frees the seals or springs.. i will try and start it tomorrow and hope it will have enouph power to drive it around for a bit.

 

well i didnt have anyluck. i did a compression test and theres still 0psi on the rear rotor.i let it idel for about 45 minutes n went to pull it around the block but there asnt any power over 25oo just starts flooding out and poping it *** off, so i think im going to pull it n take it from there.

if the rear rotor is the only problem can i just pull that one out and free the seals up with out pulling the front one out?