Cutting my losses on my rx7

[lanciachris]

Update is.... it wont fire. Cranks strongly, can smell a little fuel, turning it over by hand with the plugs out gives a good strong hiss. Spark plugs are .. well they arent great and they dont even look to be the right type but they worked before and ought to work again. The leads are brand new but ive tried refitting the old ones just in case... no joy. Tried easy-start but its just like its not even trying to spark!

*wanders off to stick a spark plug on the end of a lead and see if the spark looks ok.

Im all up for a temperemental car but this is a little too much.

Update - Victory! when I replaced the fan belt I had removed the dizzy cap and electrical connections to get more leverage to tension the belt... When I refitted the connections I managed to somehow mangle one of the contacts so it wasnt actually fitted within the connector, but rather bent to the side... fingers crossed it behaves properly in temperature et all now!

[grinder]

the plugs - should have a flat end - looks like a circle in 4 qaurters with a probe in the centre - i can get a pic if you like ??

[lanciachris]

in that case im wondering how my plugs havent chomped the rotor to bits (or vice versa).. i did think it was odd as i thought they should be flat as you said.. they arent.

The plugs that are in there look like the right hand one in this picture

http://www.powerlabs.org/images/newplugs.jpg

Today, the car is still overheating as badly. It does however pull properly, still stalls at idle etc...

Found a cheap golf ill use whilst i try and fix the rx7

[grinder]

hummmm they look like cross fire plugs for a normal car ?!?!

what you need is http://www.mazdarotaryclub.com/forums/forum-photos/Spark-Plugs/OLD-BLACK-BUR9EQP-ELECTRODE.JPG

apart from that you want clean ones !! LOL

how quick does it over heat ?? and by how much ?

stu

[lanciachris]

It overheats good and proper (ie boiling coolant) after about maybe 5 minutes in town driving starting at normal temperature. On constant 60 mph roads the temperature is stable / cools.

The fan coupling behaves properly, the top hose gets hot so I guess the thermostat is ok... no sign of leaks from the radiator cap. I am properly bleeding the system each time.

The way I see it now, either theres a leak im not seeing, or the water pump is shagged. I dont know if it could be the water seals in the engine, but i doubt it would run properly and suggest good compression? I dont notice any water under the car unless it has properly overheated and spewed it out the header tank

[grinder]

depending on what you want to spend - change the rad cap - it could be failing and not pressurising the system properly

if you take it off - does the spring move OK - and it should be rated at 0.9 bar ( i think its bar )

not sure what else it could be ... my mate had the same prob - would run great - get it home and it would shoot coolant from the overflow bottle .. i will ask him when i see him

[lanciachris]

Car behaved perfectly today.. only thing I\'ve done was ensure that the rad cap is the correct pressure and that it moves freely...ill replace it and see where that takes me.

Now i wonder what i should do with the golf ive just bought...

[grinder]

humm so it ran OK today - i hate problems like that - really hard to trace down

[Brett]

Sounds stupid I know, but have you checked that the fan is acyaully working?  They are hydrostatic and the fluid does tend to leak out or it loses its properties. (Some become really visous allt he time which kills the belts, others just become very loose so you never get any cooling, the fan just free wheels)

[lanciachris]

Possibly the fan - when cold it doesnt freewheel which I gather it should do - i havent checked it when hot yet - it should be fairly stiff then correct?. Ive got myself a banger that im using for the commute now so I wont kill the rexx anymore by driving it as it is.

This weekend im going to replace the radiator cap and thermostat i guess, and check out the viscous coupling.

If the coupling is toast, where do I get a replacement? or now that the air pump is removed perhaps I would be better off going for an electric fan to reduce the load on the remaining belt; although unless I can find one that doesnt require a world of fabrication to mount that idea is less than entirely attractive.

[grinder]

so you removed the air pump .. did you put the dual belt on the alternator ??

if not this could be your prob - means that you only have one belt running the water pump - if this slips you are in a world of trouble

stick the air pump back on ( just the main bit ) and see if it helps

there are a few threads covering this already

stu

the air pump does something with the idle at low revs aswell - i would be really tempted to stick it back on

[lanciachris]

tbh i didnt get a choice in the matter. I booked the car in at rx-motors for a replacement exhaust manifold, expecting a like-for-like jobbie, but they actually put on what I assume is a performance manifold without the thermal reactor gubbins. This removed the use for the air pump so they removed it too. I dont have the air pump anymore - i think they just trashed it

I only have a single belt driving the alt + water pump - have replaced this to try and see if that was the problem but no joy.

[grinder]

hummmm with a single belt it can slip and cause the water pump not to turn - and we all know that the fan is connected to that

no idea how you prove the theory though ??

http://www.mazdarotaryclub.com/forums/showthread.php?t=14205&highlight=air+pump

[lanciachris]

Well I might see if i can find a super short belt to double it up... I can pull the belt by hand and turn the engine over that way without the belt slipping, and theres no squealing to suggest it slipping when running. Not ruled out as the cause though

My current thoughts have turned to maybe the thermostat being stuck open and / or the radiator cap. What im really looking for is an explanation for why it was fine one day and bad the next... and thinking about components which fail in that style.

Also got joys of work to do on the new shed this weekend polishing it up and replacing a bashed off mirror, then fitting a stereo