supracosworth

Are there any crude methods to check for warped housing with the engine out without dissembling it? I need to make a decision today on an engine I found at the wrecker.

rotorbrain

its called prayer!!! hahaha, i dont think so man.

paul

j9fd3s

iTrader: (3)

the best thing you can do is look in the exhaust port with a flashlight

mike

supracosworth

Assuming that you are serious Mike, what signs am I suppose to be looking for in the exhaust port?

Hyperite

An apex seal thrown into the housing. Aside from that, there's not much you can tell with a flashlight if you've never looked before.
~Tom

TomsRX7

Hehehehehe, not a chance buddy. The only way to check side housings for warpage is with a straight edge and obviously you have to have the motor disassembled to do that. It is physically impossible to do it any other way.

But beyond that, why are you so concerned about housing warpage? Just make sure you get a fair warranty on the motor, do a visual inspection throug the exhaust port and make sure it has decent compression.

If you ale planning on buying a used motor and rebuilding it, you should always have the side housings lapped (resurfaced with a special machine that makes it extremely flat) anyway. So.....even if they are NOT warped, it would be silly to put it back together without first lapping them to remove the grooves that are worn in them.

-Tom

j9fd3s

iTrader: (3)

spin the engine over as you look in there. you can also see the rotor housing surface

mike

supracosworth

In this part of the world, it's caveat emptor, none of the wreckyards warrant used engines. My engine used to be strong before the o-ring seal broke so instead of gambling on something of unknown origin and state of health, I was minded towards rebuilding it.

Couple hours of intensive research later, i realise that the rebuild kit and gaskets alone will cost over a grand. I'm not so sure anymore which route to take.

If I'm getting a used engine, I'll only get a half cut but not engines just lying around without a harness. Come to think about it, there's no reason why any engine in good state of health should be separated from its harness. Only explaination must be someone swapped a bad one out and retain the harness in the car for the new engine. Does that make sense?

One more silly question. If the engine is not leaking, do you think adding a can of CRC blockweld would be a good idea in any event to shield the o-ring seals from the elements?

es

Well, you can pull the oil pan off & look at the bottom of the rotor housings. If they look like regular aluminum then *Chances are* they will be fine, but you wont know for sure until you mic them with the engine apart.

If they look varnish colored then that is a sign the motor has overheated & the rotor housings are probably warped.

I've never heard of end-plates warping. They are Iron! They do wear & need to be lapped, but that's quite a bit different...

Also, I wouldn't lap them just to lap them. If they are minimally worn low mileage then I'd just re-use them, but YMMV.

Another thing to check is pull the exhaust manifold off & push each apex seal into the rotor & see how well it springs back out. This can tell you if there are flatened springs & broken bits.

Even if all of the above pre-checks are cool you could still find cracks around the spark plug holes from not using anti seize & over torqueing/high boost & lean conditions, or flaking of the rotor housing from high mileage/poor lubrication...

For the gamble your taking it's really hard to pass up the Mazda Re-manned motor.

Eric.

Hyperite

You can't just take off the oil pan, there's a ******* motor mount running through it. If you go that route, might as well just take the engine out and apart!

This can be a good idea, but for the love of god don't use your fingers! No matter how much it looks like a flat piece of metal, it could give you some serious cuts.

~Tom

es

Tom. I sense some hostility. I don't know what I typed to promote that, but IMO there's a big difference between removing 2 motor mounts & an oil pan (only the first 2 steps in breaking a motor down) vs: pulling the FW, UIM, LIM, rats nest/harness/fuel & oil tubes, cracking that front bolt that nearly kills all & splitting the motor...

My $.02
Eric.

TomsRX7

ES, since you've never heard of the side housings (or end plates as you called them) warping, well now you have You might want to review the Mazda Factory Workshop Manual, page C-51:http://www.scuderiaciriani.com/rx7/shop_manual.html.

As for not lapping them if they were low mileage, yeah, I would agree, buy why in the world would you have a low mileage engine torn apart? Any time I've ever torn an engine down, it was cuz it had quite a bit of mileage. (the only situation I can think of is when you've just recently rebuilt a motor, you break an apex seal, and you have to take the engine back out. But in that case, you would have just lapped the housings prior to building the motor). I doubt anything you find in a junkyard is going to be nice, low mileage. These cars are OLD. So the majority of the time, the side housings require lapping.

As for rotor housings, that's usually the very first thing on My list of new parts to be purchased when doing a rebuild. Many times, even at 30K miles you will find significant wear.

And lastly, I don't know if there was some hostility between you and HYPERITE, but I'm not trying to be. Just having an educational debate here.

Take it easy,
Tom

j9fd3s

iTrader: (3)

here's my schpiel on used engines.
ok if your motor went 80k miles and its 2k to rebuild it, or you can buy a used engine. it has 40k miles on it for 1k, its only gonna last another 40k before you have to pull it out again. so you save a little bit of dough but you have to do the labour twice, plus the used engine could be bad a 40k too. the choice is up to you, just keep in mind batman always puts used motors in his car and he's about to be on number 6

mike