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Today I “completed” my first rebuild and got everything fixed up and put back in my 1980 rx7.
The first issue was the dreaded drip while pouring in the coolant, it’s not a huge leak but it’s a steady one even with no pressure in the system yet. I used all Mazda and Atkins seals for this project and they all seemed to fit just fine, hylomar and rtv was used where needed as well. The leak seems to be coming from a housing seal but until I get the manifold and intake off I can’t see exactly where but I don’t know where else it could be behind there.
The second issue was I tried to start it anyways just to see if it would run and I ran into the same issue that I started with where the engine turns over just great, now the compression sounds great too. But the engine refuses to fire and floods after every attempt. All the spark plugs are brand new and I rebuilt the original Nikki carb at the same time I rebuilt the engine so that shouldn’t be an issue.
I'm very new to these engines and I could be making a very easy mistake while trying to start this thing I have no idea.
my questions are if anyone knows anything about fixing those little annoying coolant leaks it out tearing the engine apart again, and is there something I’m missing when trying to start the car that I might not be aware of?
any help is greatly appreciated, trying to figure out these cars is a lot of fun and I can’t wait till I have it running again.
Here's a few things to check if you haven't already:
fuel pump gph at the carb
spark (ignition) at the plugs
check and double check to make sure the distributor is stabbed properly
compression test
thanks I appreciate it,
I’ve done checks on the spark and compression, next time I’m in the garage I’ll check the fuel pump output and check out if there’s anything wrong with the distributer but everything seemed spot on during installation.
From the Department of That Ship has sailed-
I rebuilt one of my 80s and one of the concerns was, yeah, a leaky improper seal outta wack somewhere. And what to do to check B4 install.
THIS little gadget pretty much guaranteed if I had a prob, I would be aware of any leak while the short block was still on the stand! https://www.pineappleracing.com/cool...estercspt.aspx
Too late for Tyler, but if this helps other novice builders who want to tackle the actually-pretty-rewarding job of doing your own build, this little confection is
$$ well spent, even if you use only once (FYI: my 12A was tight).
After a bit of digging I’m going to try replicating what was it preformed in this thread to get a season or two out of this engine. My engines borderline high mileage and I only expected to get a season or two out of it post rebuild due to housings being on the outs.
hope if anyone is in the same boat they can use this as well.
On the restart part of the question anyone got a link to a post here called something like ‘the mother of all restart posts’ or something similar....would be very good info for this poster. Tried searching and can’t find it. A few weeks ago I DID find it and was very useful for first start of my amateur don’t know what I am doing rebuild. Only thing missing if I remember rightly was checking oil pump was primed so search that one too... involved uncoupling an oil line and hand turning the engine to make sure oil was moving. Mine was NOT so had she started I would have wrecked my just rebuilt engine. I have a good solution for priming the pump, let me know if needed.
On the restart part of the question anyone got a link to a post here called something like ‘the mother of all restart posts’ or something similar....would be very good info for this poster. Tried searching and can’t find it. A few weeks ago I DID find it and was very useful for first start of my amateur don’t know what I am doing rebuild. Only thing missing if I remember rightly was checking oil pump was primed so search that one too... involved uncoupling an oil line and hand turning the engine to make sure oil was moving. Mine was NOT so had she started I would have wrecked my just rebuilt engine. I have a good solution for priming the pump, let me know if needed.
Thanks for this, I will not rest till I find that post. Also thanks for the heads up, I didn’t know that was something to look out for so I’ll double check it before I try and start it again
Found it! Don’t know how to link here so screenshot attached that you can search from.
On the elephant in the room... coolant leak. Totally wishful thinking here but not coming from the coolant pump to front cover gasket and running down the side of the engine? I too had the dreaded drip drip drip on first fill and some research revealed a
newbie mistake in that I missed a couple of thin washers between pump and cover. This would be a godsend as an easy fix.... but sounds like leak is further back?
On the oil pump. I tripped over the issue totally by accident. Does not get mentioned much in restart threads as I guess most are not restarting from a fresh rebuild. Diagram of oil path attached. Full credit to j9fd3s Armchair Engineer in this forum for pointing me in the right direction. If you disconnect the front oil line from the oil cooler and put the end of a line in a bucket, then turn the engine clockwise (looking from front if engine) using a socket on the main pulley bolt, oil should be pumped out of the end of the line. If no oil, then the pump needs to be manually filled to get it working (primed). To do remove the front oil line from the engine and attach a clear plastic hose a couple of feet long and funnel to the hole where the oil line was attached to the engine. OReilly sells a tube and funnel combo for under $20. I used some plumbing fittings I had around to attach tube to engine but pretty much anything you can zip tie and duct tape together should work as it’s not under pressure. Then hold the funnel higher than the engine and slowly pour oil into the tube until you see oil rising in the tube. Stop pouring and turn the engine like before watching the oil in the tube. If it’s worked the oil should rise up the tube as it’s being pushed by the pump. If it’s working then remove the plastic pipe (messy) and reattach the oil line. Install a new oil filter first wiping out where the filter screws in so that everything is dry except for the oil filter seal. Pull the fuel pump fuse so the car can’t start and crank the engine over for three or four ten second blasts. Then remove the oil filter and if it’s wet with oil you know oil is moving. Last check, when the car finally starts watch the pressure gauge. Should see something around 30psi idle 60psi when revving.
Last edited by Slow_sevens; May 16, 2022 at 11:55 AM.
Reason: Credit
Found it! Don’t know how to link here so screenshot attached that you can search from.
On the elephant in the room... coolant leak. Totally wishful thinking here but not coming from the coolant pump to front cover gasket and running down the side of the engine? I too had the dreaded drip drip drip on first fill and some research revealed a
newbie mistake in that I missed a couple of thin washers between pump and cover. This would be a godsend as an easy fix.... but sounds like leak is further back?
On the oil pump. I tripped over the issue totally by accident. Does not get mentioned much in restart threads as I guess most are not restarting from a fresh rebuild. Diagram of oil path attached. Full credit to j9fd3s Armchair Engineer in this forum for pointing me in the right direction. If you disconnect the front oil line from the oil cooler and put the end of a line in a bucket, then turn the engine clockwise (looking from front if engine) using a socket on the main pulley bolt, oil should be pumped out of the end of the line. If no oil, then the pump needs to be manually filled to get it working (primed). To do remove the front oil line from the engine and attach a clear plastic hose a couple of feet long and funnel to the hole where the oil line was attached to the engine. OReilly sells a tube and funnel combo for under $20. I used some plumbing fittings I had around to attach tube to engine but pretty much anything you can zip tie and duct tape together should work as it’s not under pressure. Then hold the funnel higher than the engine and slowly pour oil into the tube until you see oil rising in the tube. Stop pouring and turn the engine like before watching the oil in the tube. If it’s worked the oil should rise up the tube as it’s being pushed by the pump. If it’s working then remove the plastic pipe (messy) and reattach the oil line. Install a new oil filter first wiping out where the filter screws in so that everything is dry except for the oil filter seal. Pull the fuel pump fuse so the car can’t start and crank the engine over for three or four ten second blasts. Then remove the oil filter and if it’s wet with oil you know oil is moving. Last check, when the car finally starts watch the pressure gauge. Should see something around 30psi idle 60psi when revving.
Thank you there’s some really good information in there for new builders such as myself, I was really hoping it was just the water pump but I haven’t been able to find any trails and it’s pooling up at the top left thermal reactor nut so I need to get the intake off to see the source
Was in the same place myself six months ago. Multiple leaks and looking at an engine rebuild. I would suggest UV dye in the coolant. Seeing exactly where the leak was coming from helped me face the inevitable. Do it at night and it really shows where the leak is.
if you decide on a rebuild I have one of the Pineapple pressure testers another poster mentioned. I can mail it to you no charge, just mail it back to me when done.
Tyler, the common place for leaks on the passenger side is the intake manifold o-rings. Take the manifold/carb off and see if one of them was damaged or mis-aligned when you put the engine together. It's a pretty easy check. If a seal was messed up inside the engine that's a much bigger problem, so start with the easy and usual suspects.
I really appreciate that but since the engines not pristine anyways I want to avoid another rebuild before getting in on the road for at least a season or two and I don’t plan on giving up on the rotary broke life so next time around I’ll try and pick up one of those tools for myself. Thanks for the offer though!
Tyler, the common place for leaks on the passenger side is the intake manifold o-rings. Take the manifold/carb off and see if one of them was damaged or mis-aligned when you put the engine together. It's a pretty easy check. If a seal was messed up inside the engine that's a much bigger problem, so start with the easy and usual suspects.
Thank you, thats really good to know, I’ll take a look at that as soon as I can before I resort to the coolant system sealer. Gotta love the taking off the intake with the original thermal reactor in the way though lmao who came up with that design.
Thank you, thats really good to know, I’ll take a look at that as soon as I can before I resort to the coolant system sealer. Gotta love the taking off the intake with the original thermal reactor in the way though lmao who came up with that design.
Coolant system sealer will wreak havoc on the engine irons. It generally will not work and is a bear to clean out. It also is not that great on the rad.
Tyler, the common place for leaks on the passenger side is the intake manifold o-rings.
Max you were right on the money, I took it all apart again to find traces of moisture across the intake gasket from where the rear O ring sat. I’m not too sure why the gasket was leaking everything looked fine to me so I must’ve misaligned it while putting it on the first time. Slapped some Vaseline on it and put it back on and now she’s as dry as a nun 😄
as for the no start. I tried bypassing the fuel pump by doing a gravity feed with a jerry can and clear hose to the fuel in of the carb and I got combustion but the engine couldn’t seem to catch and do it on its own. Possibly something to do with all the vacuum lines I didn’t put on but oh well we will see tomorrow if she’ll fire up after I actually get the carb installed.
thank you everyone for the sources and for the help on this topic.
If you used vasoline sometimes the vaseline swells the seals and make them leak. All youll need to buy is new coolant seals and reopen it and just replace the coolant seals use hylomar next time around.
