ShooterMcGavin

Hey guys!

I just picked up a 1980 SA RX-7 S 4 speed. It's been sitting in my parents garage for 7 years and I got it up and running a few weeks ago and shipped it out to Colorado to be my new auto-x/track toy.

I was told the previous owner had tracked it as well and I'm starting to see some of his mods. It has a road race header, can't tell what brand, I think the rest of the exhaust is stock. It also has the A/C removed and the ignition coils were upgraded to Accel Super Stack 8140 ignition coils. I couldn't find any info on those coils on here, anyone have any experience with those coils?

Here are some shots, let me know if you spot any other mods or happen to know what brand header that is!





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Here is the rattle, it's coming from the passenger side of the engine and sounds like it might be in the carb. The rattle speeds up when you give it some gas too.

Click on the picture to head to my Flickr page and watch the video, I couldn't figure out the video embed code.

woodmv

iTrader: (8)

It appears that you have an SA intake manifold on an FB engine. You can tell because it looks like there is an opening in the center iron directly beneath the intake manifold which I think I can see in the picture of your header. That port is for air injection and with (what appears to me to be) your SA manifold, it is open to the atmosphere. There was lots of discussion on this topic recently on the forum here:

https://www.rx7club.com/1st-generati...-have-1104049/

I listened to the video and it sounds like you have something that is not tightened down quite enough that is rattling and it kinda sounds large-ish. Check the header bolts and exhaust connections. Maybe one isn't tightened completely. I think I can kinda hear a loud ticking noise, which may be the open air injection port if my eyes do not deceive me looking at the picture of your header and that you actually do have an SA intake manifold on an FB engine.

ShooterMcGavin

Thanks for the response! By air injection port do you mean the air control valve?

My secondary air pump is seized currently and the belt is disconnected, it doesn't sound like the noise is coming from there but could that affect it?

I noticed what you meant about the notch above the manifold, did FB motors get put into SA car before the FB was available?

ShooterMcGavin

I'm going to start with the water pump and see if that does anything. There is a new one on there but maybe it was out of balance?

woodmv

iTrader: (8)

No problem, and no, the air injection port is in the center iron above your exhaust header, directly below the intake manifold. The air control valve is normally attached to the intake manifold; however it looks like yours was removed and a block off plate installed in its place.

Could the air pump being disconnected affect the sound? Maybe. Could the fact that it's disconnected affect performance? Many people remove those. The SAs are unique in that they had the thermal reactor because they had no catalytic converter, and the air pump was part of that system. The FBs did away with the thermal reactor and air pump and used a catalytic converter.

The square hole is actually below the manifold, and above your exhaust header. It will contribute to a loud exhaust sound.

SAs are called SAs because the first letters of the VINs started with SA. FBs are named FB because in 81 the NTHSA instituted the standardized format for VIN numbers and Mazda used FB for the first two characters of the VIN beginning in 81.

So to be a bit more accurate, from the factory, SAs and FBs mostly came with 12A motors except the GSL-SE cars which came with 13B motors. I am not sure if GSL cars came with 13Bs or not. Many people swap in and out motors of various years.

Hope that helps. This is a great website and resource for information if you search around. I find that if I google a question I have it will bounce back a hit to this website. That method of searching can yield faster results than the search function here.

aeenox

Sorry I posted in the wrong thread

Qingdao

iTrader: (3)

Those coils suck; I had a pair. The diamond coils are better.

ShooterMcGavin

I've been trying to search as much as possible and up until this new rattle, I've found the answer to everything I was looking for! I know I've got an SA based on the VIN and after reading through that thread you posted, it seems that hole was blocked internally since there's no noise coming from right there.

I've fully removed the air pump and capped that hose for now. When I first got it running and drove it around a couple times, it wasn't making that noise, and that was with the belt removed from the pump so I doubt that's it. It started right after the car was pulled off the transport trailer.

I've read mixed reviews on removing the air pump. Since there's no cat, I shouldn't have to worry about anything in the exhaust getting clogged right? I haven't seen that it affects performance really one way or another, so if that's the case I'll probably just save myself the money and not replace it.

Thanks for the info, what was so bad about them? Also, what are the diamond coils?

New water pump goes in tonight so hopefully that'll be the fix! I got a reman from Advanced Auto parts and went to pick it up last week but it was rusty right out of the box.

Qingdao

iTrader: (3)

The yellow coils didn't rev as high for some reason. The diamond coils will rev to the sky. Diamond coils are the OEM coils for these cars.

Go to a pick and pull and find a car with a factory diamond coil. Pull it and shake it in your hand. If you can hear oil rushing around inside of the coil its still good. If there is no oil the coil is burned out.

ShooterMcGavin

Good to know, I've been keeping an eye out at the local yards but they don't come through too often.

ShooterMcGavin

I threw in the new water pump and the rattle got louder.

I'm wondering if I have a clog somewhere in my cooling system since my radiator only took half of the recommended amount of coolant. After idling the car a bit, the coolant level didn't drop, it actually started rising and spilling out of the top of the radiator without the cap on.

I checked the drain plug on the engine and there was fresh coolant there so it's getting into the engine but not circulating? I'm stumped here, any thoughts on where to look next would be appreciated!

Qingdao

iTrader: (3)

Did you drain the system before putting the pump on? If not then the coolant in the block is why you only used half the recommended level of coolant.

You should be able to watch the coolant move through the radiator while the car is running. Rev it slightly and you can see it move with the cap off.

If its not getting hot and there is coolant in the tank don't think anymore about it. Take it for a spirited run with a gallon of coolant or distilled water on hand. Keep an eye on the temp gauge and if you have an IR thermometer use it.

Dunno what to say about your rattle. Check the fan bolts; if it got louder after installing a pump that's where I'd look.

ShooterMcGavin

The radiator and block were fully drained before swapping the pump. I made sure to tighten the fan bolts down in a star pattern and I know they're tight.

I could hear the ticking starting slowly right from the second I turned the ignition over, before it was even really moving.

I did notice that the main crank pulley had just the slightest wobble to it so maybe I'll check those bolts. I had pulled off the A/C pulley since that system was removed, does that act as a harmonic balancer in any way?

Qingdao

iTrader: (3)

No, its not a harmonic balancer. There is a big counter weight behind that front cover that you can't see. The A/C pulley does have a particular way of bolting up there though; however it is not possible to bolt it up wrong.

Does the rattle get worse as the engine revs? is it rhythmic? Does it sound like metal banging? Does it have a loose kind of tingy sound or is it clunky like two large thick things hitting each other?

Best idea with a rattle or noises coming from a vehicle is to get a stethoscope and have a friend encourage the noise with the throttle while you look for it. Or I guess I should write listen for it.

ShooterMcGavin

When you say there's a counter weight behind that front cover, do you mean the two lower crank pulleys?

The rattle does get worse as the engine revs and it's rhythmic for the most part. Here's a link to a video of the car running, just have to click on the picture.



It definitely sounds like there are two pieces of metal clanging together. I tried using a stethoscope on my own and couldn't really hear much, maybe a harbor freight one isnt the best option.

I'll give it another shot though and see if I can find anything else.

ShooterMcGavin

After talking with my mechanic and reading/listening to some posts and videos in the 2nd and 3rd gen sections I'm starting to fear the worst, spun rotor bearing.

I'm going to drop the oil pan this weekend and check the pickup tube and see if there are any shavings in the oil.

Qingdao

iTrader: (3)

Your mechanic isn't a rotary guy is he?

Spun bearing on a piston engine yup. definitely. A rotary doesn't use half moon bearings like ones on a crank of a piston engine. It uses complete circles that go all the way around the E-shaft. If you spin a bearing all you notice is a wee loss of compression. I spun a bearing last year and didn't know until I tore the engine down.

That sounds like spark nocking of some kind; that can be cause by ancient fuel or ignition issues.

Do you still have the air pump hooked up?

HF stethoscope is fine. Shoot I used to use a screw driver till I got my HF stethoscope. Just place it on all parts of the engine. Listen closely for the noise if you can hear it pick up the scope and move it to an adjacent piece of metal. The noise in the stethoscope will either get louder or quieter (like playing hot/cold). Move closer till you've located the origin of the sound.

Good call on changing the oil to see if there are any shavings in the oil.

ShooterMcGavin

He's not a rotary mechanic but has some experience with them. I was looking up other videos on this forum of FC and FD (some FB) engines making odd clunking/rattling noises that couldnt be tracked down to any specific piece and they almost always ended up being bad rotor bearings.

The fuel in the car is fresh and I'll double check the spark to the plugs, could it also be caused by timing?

The air pump is off the car because it's seized up and I need a new one. Does the 13B (FC) air pump fit on a 12a? I ask because an FC just showed up in the local junk yard. Also, I got the car started without the air pump and it ran for a couple days without making that noise so I'm not sure that it'll help.

I'll get to checking the oil this week.

Qingdao

iTrader: (3)

Timing is what I meant. Go ahead and loosen the distributer lockdown bolt and turn it slightly while the car is running. If the sound goes away you know its the timing. If the sound doesn't change at all when you turn the distributer you know its outside of the block; another words front cover/ random rattle.

I wouldn't drop the oil pan... just seems like a pita. The screen on the pickup tube is mostly just to keep large rocks that could be in your oil from the pump. If you have metal shavings from a bearing in your oil they will be in your oil filter. Cut that in half.

ShooterMcGavin

Update!

So I was able to isolate it to something in the front cover. I hand cranked the engine with the spark plugs out and it made the knock noise anyways so it's not the timing. Distributor or oil pump maybe?

Click the picture to watch the video so you can see what I mean.

Qingdao

iTrader: (3)

Check your clutch slave cylinder bolts... and the covers on the bell housing. The slave cylinder bolts protrude through to the flywheel and can hit it. I would doubt it being in the front cover, just because there isn't much in there that has the ability to hit anything. Save your front stationary gear bolts have backed out.

Really sounds like the flywheel is hitting something.


Also, you're spinning the engine backwards.

ShooterMcGavin

Whoops, I guess I was spinning it backwards, I've got a lot to learn here haha.

How would the bolts on the slave be hitting the flywheel? If they protrude through by design then what would cause it to hit now, I would think the bolts would back out over time and go in the opposite direction. I do have a lot of play in my clutch pedal though, it's pretty loose but still shifts just fine, related?

I'll take a look at my bell housing covers, the flywheel inspection plates right?

Qingdao

iTrader: (3)

Does the noise go away with the clutch peddle depressed?

They do protrude through, but if the flywheel isn't tight* it may hit the bolts. Also, could be something else inside of there. Besides its easier to inspect the flywheel than the front cover. *if the e-shaft bolt is loose it will cause a quazi rhythmic nock, but only if the clutch is not depressed.


HOWEVER, inspecting inside the front cover can be accomplished by removing the distributer and having a look with a mirror or a cheapo bore scope (you can find bore scopes on ebay for about $5).

ShooterMcGavin

Figured it out, the main crank pulley was loose and out of balance. I had to hand crank the engine really slowly for a while to pinpoint to source of the sound and was eventually able to see the pulley wobble and snap against the mounting point.

A couple new screws later and it's purring! Thank god it was something that small and didnt require an overhaul.

I really appreciate all the attention the thread got, definitely looking forward to spending more time on here!