Engine trouble, I need the gurus!
07-09-07, 02:58 AM
#1
Junior Member
Thread Starter
Join Date: Dec 2006
Location: L.A
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
Engine trouble, I need the gurus!
My friend picked recently picked up a 1980 with a 12a engine. The person he bought off of said that they ran into engine problems after neglecting to give it an oil change and they have no need to for it anymore. So I encouraged him to pick it up knowing we would have some engine work and maybe a complete rebuild.
So here's the symptoms
The engine does start and everything appears to be connected properly, working AC and all. However, when we start the car the dipstick sort of rocks in and out of the engine and very small amounts of oil appear to be shooting out as the dipstick comes in and out. Another symptom is that when the engine is running, the the your foot must be on the throttle or else the engine will shake violently then stall. The engine does not act up above 900rpm while having foot on the throttle. The last symptom I have noticed is that while driving the car (I drove it about 50 yards) there are very loud backfires and some gray smoke coming from the exhaust.
Do any of you know what might be the problem?
P.S Do any of you recommend DIY-RE?
So here's the symptoms
The engine does start and everything appears to be connected properly, working AC and all. However, when we start the car the dipstick sort of rocks in and out of the engine and very small amounts of oil appear to be shooting out as the dipstick comes in and out. Another symptom is that when the engine is running, the the your foot must be on the throttle or else the engine will shake violently then stall. The engine does not act up above 900rpm while having foot on the throttle. The last symptom I have noticed is that while driving the car (I drove it about 50 yards) there are very loud backfires and some gray smoke coming from the exhaust.
Do any of you know what might be the problem?
P.S Do any of you recommend DIY-RE?
07-09-07, 05:45 AM
#2
Audio Cronic Syndrome
Join Date: Nov 2003
Location: Anacortes, WA Hometown: P.O., WA
Posts: 890
Likes: 0
Received 0 Likes
on
0 Posts
first, for all the symptoms except the oil thing, I believe its the carb. If the car sits for too long of a time, the small jets, bowls and passages in the stock nikki carb get very clogged with varnish. Have it rebuilt or upgrade to another carb, holley, dellorto, mikuni.....or you can have your nikki rebuilt.
And I'm just guessing but it seems like an excess of pressure in the crankcase causing oil to come out. check to see if the crankcase hose (found connected to the oil filler tube, isn't blocked with something...
start there.
And I'm just guessing but it seems like an excess of pressure in the crankcase causing oil to come out. check to see if the crankcase hose (found connected to the oil filler tube, isn't blocked with something...
start there.
07-09-07, 10:43 AM
#3
Full Member
iTrader: (3)
Join Date: Mar 2006
Location: Huntersville, NC and occasionally back in Freeport, NY
Posts: 207
Likes: 0
Received 0 Likes
on
0 Posts
^ like he said, the carb is the most likely reason why the car won't stay running
The oil could be way overfilled, causing the situation you described with the dipstick.
And SA's (1979 and 1980 models) are notorious for backfiring. Repair the carb first. If it still excessively backfires after that, the culprit is a failed air control valve. You're options then are either replace it, attempt to repair it, or change the exhaust manifold to a header and subsequently change the heat exchanger to a catalytic convertor. This is a legal mod in Cali since it's an emissions upgrade and the thermal reactor of SA's is NLA. Definately rebuild the carb first though, cause it alone could be the cause of the backfires.
DIY-RE? Do it yourself renesis? If you have the engine available, SURE! You'll need a custom exhaust manifold though as there aren't any ready made options, and probably never will be to fit our cars. Dunno if the oil pan or front cover are interchangable with older rotaries either. Custom mounts may be in order.... But it would be mas cool, I don't think anyone has done it yet.
The oil could be way overfilled, causing the situation you described with the dipstick.
And SA's (1979 and 1980 models) are notorious for backfiring. Repair the carb first. If it still excessively backfires after that, the culprit is a failed air control valve. You're options then are either replace it, attempt to repair it, or change the exhaust manifold to a header and subsequently change the heat exchanger to a catalytic convertor. This is a legal mod in Cali since it's an emissions upgrade and the thermal reactor of SA's is NLA. Definately rebuild the carb first though, cause it alone could be the cause of the backfires.
DIY-RE? Do it yourself renesis? If you have the engine available, SURE! You'll need a custom exhaust manifold though as there aren't any ready made options, and probably never will be to fit our cars. Dunno if the oil pan or front cover are interchangable with older rotaries either. Custom mounts may be in order.... But it would be mas cool, I don't think anyone has done it yet.
07-09-07, 11:15 AM
#4
No I think he means the DIY-RE series of instructional engine rebuild videos (which, yes, feature an -RE engine, but the skills you learn transfer over).
I've heard they're very good videos, so I wouldn't hesitate to get them if you have the cash.
The guys here covered it so far
- Do an oil change first. 4.5L of 10w30 non-synthetic and an oil filter that isn't made by fram. Preferably the Purolator PureONE, which is my filter of choice. Double check the shop manual to make sure that number is correct, because that's what my '84 takes but it doesn't have a front-mount oil cooler.
- Drain the gas tank (you may have a drain plug or you may have to take the fuel line off the car, put it in a jerry can and turn the key forward to activate the fuel pump and pump it out). Old gas causes its own problems and makes it harder to find the real problems.
- Change the fuel filter and refill with fresh gas and some fuel system cleaner
- Rebuild the carb. Use a rebuild kit by Hygrade (the one I have has "Kit 1556" written on it, but it's the only kit for a '79-85 Rx7, so you should be able to source one out). There's a good carb rebuild manual here:
http://www.wankel.net/~krwright/cars/rx7/manuals.html
- If you can verify that replacing your stock thermal reactor and heat exchanger with a header/cat combo is indeed legal where you are, definitely do it
That should get you in good running condition, assuming that your engine itself isn't forked and your ignition system is running well.
The lucky thing about being anywhere in Cali is that you're a stone's throw away from some of the best rotary shops on the continent, compared to me. Racing Beat and Mazdatrix are both down there somewhere.
Jon
I've heard they're very good videos, so I wouldn't hesitate to get them if you have the cash.
The guys here covered it so far
- Do an oil change first. 4.5L of 10w30 non-synthetic and an oil filter that isn't made by fram. Preferably the Purolator PureONE, which is my filter of choice. Double check the shop manual to make sure that number is correct, because that's what my '84 takes but it doesn't have a front-mount oil cooler.
- Drain the gas tank (you may have a drain plug or you may have to take the fuel line off the car, put it in a jerry can and turn the key forward to activate the fuel pump and pump it out). Old gas causes its own problems and makes it harder to find the real problems.
- Change the fuel filter and refill with fresh gas and some fuel system cleaner
- Rebuild the carb. Use a rebuild kit by Hygrade (the one I have has "Kit 1556" written on it, but it's the only kit for a '79-85 Rx7, so you should be able to source one out). There's a good carb rebuild manual here:
http://www.wankel.net/~krwright/cars/rx7/manuals.html
- If you can verify that replacing your stock thermal reactor and heat exchanger with a header/cat combo is indeed legal where you are, definitely do it
That should get you in good running condition, assuming that your engine itself isn't forked and your ignition system is running well.
The lucky thing about being anywhere in Cali is that you're a stone's throw away from some of the best rotary shops on the continent, compared to me. Racing Beat and Mazdatrix are both down there somewhere.
Jon
07-09-07, 11:18 AM
#5
The more I think about it, the more I think your engine might have something seriously wrong with it. That extra pressure causing the dipstick to rock may be from pressure releasing from the combustion chamber through a bad oil seal or something.
If rebuilding the carb doesn't solve the problems I'd definitely tear the whole engine down. If you're blowing a lot of blue smoke (a little is normal), tear the engine down first, don't keep troubleshooting because you could be causing more damage.
Jon
If rebuilding the carb doesn't solve the problems I'd definitely tear the whole engine down. If you're blowing a lot of blue smoke (a little is normal), tear the engine down first, don't keep troubleshooting because you could be causing more damage.
Jon
07-09-07, 12:28 PM
#6
Check Compression.
Check the timing breifly (this should be okay).
Oil probably overfilled.
Replace/Rebuilt the carb.
Essentially, I do things in the order that doesnt cost any money. Once those options are exhausted, THEN, I spend money. Dont spend money on it until you have to.
Check the timing breifly (this should be okay).
Oil probably overfilled.
Replace/Rebuilt the carb.
Essentially, I do things in the order that doesnt cost any money. Once those options are exhausted, THEN, I spend money. Dont spend money on it until you have to.
07-09-07, 03:03 PM
#7
Nikki-Modder Rex-Rodder
Join Date: Feb 2001
Location: Trying to convince some clown not to put a Holley 600 on his 12a.
Posts: 2,890
Likes: 0
Received 14 Likes
on
6 Posts
The carb should probably be rebuilt, but generally you wouldn't have it running at all if the carb was that bad.
I think you have a timing issue.
I think you have a timing issue.
Trending Topics
07-09-07, 03:11 PM
#8
Rotary Freak
Join Date: Sep 2002
Location: SF BayArea
Posts: 2,815
Likes: 0
Received 0 Likes
on
0 Posts
Check dipstick: Rotarys do not run well if overfilled with oil.
remove radcap and check coolant. If it's slippery, ugly and oily you have a coolant leak that might explain the clouds of exhaust smoke. We have a 'temporary' fix that usually works for a year or two. Usually, that's why the PO was anxious to sell the 7: he thought he needed a whole engine overhaul. I suspect that EVERY 7 on the road has overheated and blown the coolant seals at least once, simply because they will overheat so quickly (due to low mass of engine) upon loss of coolant, even when operated by the most conscientious owner (like me). It can happen in a couple blocks or a mile on the highway.
And I recommend synthetic oil, now. For one thing it burns cleaner. For another it survives the overheating that blows coolant seals much better.
If you can drive it, add some gas cleaner to the tank. Maybe it'll cleanup your carb, or maybe it won't, but it's cheap and easy.
When it's running right, be sure to add 6-8 oz. of MMO or 2-cycle oil to every tankful to keep your rotary humming.
remove radcap and check coolant. If it's slippery, ugly and oily you have a coolant leak that might explain the clouds of exhaust smoke. We have a 'temporary' fix that usually works for a year or two. Usually, that's why the PO was anxious to sell the 7: he thought he needed a whole engine overhaul. I suspect that EVERY 7 on the road has overheated and blown the coolant seals at least once, simply because they will overheat so quickly (due to low mass of engine) upon loss of coolant, even when operated by the most conscientious owner (like me). It can happen in a couple blocks or a mile on the highway.
And I recommend synthetic oil, now. For one thing it burns cleaner. For another it survives the overheating that blows coolant seals much better.
If you can drive it, add some gas cleaner to the tank. Maybe it'll cleanup your carb, or maybe it won't, but it's cheap and easy.
When it's running right, be sure to add 6-8 oz. of MMO or 2-cycle oil to every tankful to keep your rotary humming.
07-09-07, 05:42 PM
#9
Audio Cronic Syndrome
Join Date: Nov 2003
Location: Anacortes, WA Hometown: P.O., WA
Posts: 890
Likes: 0
Received 0 Likes
on
0 Posts
Check dipstick: Rotarys do not run well if overfilled with oil.
remove radcap and check coolant. If it's slippery, ugly and oily you have a coolant leak that might explain the clouds of exhaust smoke. We have a 'temporary' fix that usually works for a year or two. Usually, that's why the PO was anxious to sell the 7: he thought he needed a whole engine overhaul. I suspect that EVERY 7 on the road has overheated and blown the coolant seals at least once, simply because they will overheat so quickly (due to low mass of engine) upon loss of coolant, even when operated by the most conscientious owner (like me). It can happen in a couple blocks or a mile on the highway.
And I recommend synthetic oil, now. For one thing it burns cleaner. For another it survives the overheating that blows coolant seals much better.
If you can drive it, add some gas cleaner to the tank. Maybe it'll cleanup your carb, or maybe it won't, but it's cheap and easy.
When it's running right, be sure to add 6-8 oz. of MMO or 2-cycle oil to every tankful to keep your rotary humming.
remove radcap and check coolant. If it's slippery, ugly and oily you have a coolant leak that might explain the clouds of exhaust smoke. We have a 'temporary' fix that usually works for a year or two. Usually, that's why the PO was anxious to sell the 7: he thought he needed a whole engine overhaul. I suspect that EVERY 7 on the road has overheated and blown the coolant seals at least once, simply because they will overheat so quickly (due to low mass of engine) upon loss of coolant, even when operated by the most conscientious owner (like me). It can happen in a couple blocks or a mile on the highway.
And I recommend synthetic oil, now. For one thing it burns cleaner. For another it survives the overheating that blows coolant seals much better.
If you can drive it, add some gas cleaner to the tank. Maybe it'll cleanup your carb, or maybe it won't, but it's cheap and easy.
When it's running right, be sure to add 6-8 oz. of MMO or 2-cycle oil to every tankful to keep your rotary humming.
^sorry to say but straight from Mazda's mouth NO SYNTHETIC OIL!!! Ask anyone on the forum. I work at a dealership. There is a bulletin on this very issue. Synthetic oil DOES NOT burn thus caking up the inside of the engine when using the stock oil "injection" thats equipped with the vehicle.
But your other suggestions are very valid.
07-09-07, 06:27 PM
#10
here we go again, synthetic oil will not harm your rotary, i have used it exclusively including 2 stroke for my pre mix for the past 40,000 miles and my car uses absolutely 0 oil between changes, which are at 7500 miles with Amsoil as recommended.
Modern synthetic oils are a great lubricant and a great easy method to free up a couple of horsepower.
Dealerships should investigate the current recommendations, Mazda no longer states synthetic is a no-no. synthetic does burn, and is not an issue other than lowering the polutants in the exhaust
Modern synthetic oils are a great lubricant and a great easy method to free up a couple of horsepower.
Dealerships should investigate the current recommendations, Mazda no longer states synthetic is a no-no. synthetic does burn, and is not an issue other than lowering the polutants in the exhaust
07-09-07, 10:29 PM
#11
Rotary Freak
Join Date: Sep 2002
Location: SF BayArea
Posts: 2,815
Likes: 0
Received 0 Likes
on
0 Posts
I was a holdout for dyno oil but expert reports from Actual API Engineers here on the forum, plus my own experience running my Alfa Romeo for over 100 miles up and down a mountain with all coolant gone have convinced me that synthetic is the best.
Both theory and practice show that synthetic is best.
I will repeat, the rotary engine, having low mass, is quick to overheat when you have a coolant loss, and for a couple reasons you WILL suffer sudden coolant loss! When that happens the rotary will overheat in a matter of less than a mile. Most drivers go on too long because high mass conventinal engines will take the abuse, and that's what they know.
Even an experienced driver with 4 good running rotaries (like me!) will suffer this, just as I did a month ago with my 85SE, when I went about a mile to the store and upon stopping in the parking lot saw wisps of steam coming from under the hood. Popping the hood revealed the @$%% wire hose clamp for the heater hose on the drivers side had popped off and all the coolant dumped! After nursing a beer at the tavern for 1.5 hours and replenishing the radiator fluid with expensive Spring
Water from the Grocery store and pushing the hose back on I proceeded home with no problem. But every morning thereafter I had copious white exhaust smoke upon starting the car in the morning. Until I applied the CRC Block Seal fix (as improved by the rotary gods, of course).
It can happen to you. Be prepared.
That's the bad news.
The GOOD news is that it probably happened already to that guy who's trying to sell you an RX-7 because he knows it's smoking horribly, but not after it's warmed up. So he thinks it needs an expensive rebuild. But YOU, being forewarned and thus forearmed, know enough to stick your finger in the radiator neck, look disgustedly at the horrible greasy black gunk therein, and proclaim "I think this engine is blown and needs a rebuild! I'll give you $50 for it, take it or leave it!" It helps to sneer when you do this.
Then you take it home and apply the Temporary Fix and a day later you got a good car. Later, at your leisure, you replace the intake manifold gasket and ORings, and maybe the ORings under the beehive, as necessary.
Piston engines fail differently. For one thing they can run much longer overheated. For another, they usually fail with the inverse problem, that is, they smoke a lot when warmed up, but almost none when cold. Thus, when a cop tagged me for excess smoke from my lovely Fiat 1100 (affectionately known as 'Millicento' in Italy) many years ago, I got it cleared by parking it in front of DMV in the evening, then going in the morning to have an inspection when it was cold. No smoke.
Ya gotta learn these things to survive in this world, young fella, and I know you're a young fella because I'm pretty old and everyone is young compared to me.
Both theory and practice show that synthetic is best.
I will repeat, the rotary engine, having low mass, is quick to overheat when you have a coolant loss, and for a couple reasons you WILL suffer sudden coolant loss! When that happens the rotary will overheat in a matter of less than a mile. Most drivers go on too long because high mass conventinal engines will take the abuse, and that's what they know.
Even an experienced driver with 4 good running rotaries (like me!) will suffer this, just as I did a month ago with my 85SE, when I went about a mile to the store and upon stopping in the parking lot saw wisps of steam coming from under the hood. Popping the hood revealed the @$%% wire hose clamp for the heater hose on the drivers side had popped off and all the coolant dumped! After nursing a beer at the tavern for 1.5 hours and replenishing the radiator fluid with expensive Spring
Water from the Grocery store and pushing the hose back on I proceeded home with no problem. But every morning thereafter I had copious white exhaust smoke upon starting the car in the morning. Until I applied the CRC Block Seal fix (as improved by the rotary gods, of course).
It can happen to you. Be prepared.
That's the bad news.
The GOOD news is that it probably happened already to that guy who's trying to sell you an RX-7 because he knows it's smoking horribly, but not after it's warmed up. So he thinks it needs an expensive rebuild. But YOU, being forewarned and thus forearmed, know enough to stick your finger in the radiator neck, look disgustedly at the horrible greasy black gunk therein, and proclaim "I think this engine is blown and needs a rebuild! I'll give you $50 for it, take it or leave it!" It helps to sneer when you do this.
Then you take it home and apply the Temporary Fix and a day later you got a good car. Later, at your leisure, you replace the intake manifold gasket and ORings, and maybe the ORings under the beehive, as necessary.
Piston engines fail differently. For one thing they can run much longer overheated. For another, they usually fail with the inverse problem, that is, they smoke a lot when warmed up, but almost none when cold. Thus, when a cop tagged me for excess smoke from my lovely Fiat 1100 (affectionately known as 'Millicento' in Italy) many years ago, I got it cleared by parking it in front of DMV in the evening, then going in the morning to have an inspection when it was cold. No smoke.
Ya gotta learn these things to survive in this world, young fella, and I know you're a young fella because I'm pretty old and everyone is young compared to me.
Thread
Thread Starter
Forum
Replies
Last Post