So I'm in the middle of getting a 13b running again after it sat for nearly 10 years. I figured I'd replace the water pump and thermostat just because. As soon as I pulled the water pump off, I was like "oh crap..." Here's what the impeller of the water pump looks like.


Turns out that the car sat for 10 years with very little coolant in the cooling system. So it was essentially a closed system filled with moist air, so everything's going to rust. The inside of the water pump housing looks the same way, as does what you can see of the inside of the coolant passages. I'm going to replace everything external of the engine, but my question is what can I do about the coolant passages inside the engine in this aspect? Obviously I'd rather not have to pull the engine apart to fix this...

Next question. This engine is actually in a VW Beetle. And just to make sure, I've figured out this 13b came out of a 1st gen, but is this a 4-port or a 6-port 13b? And how do I tell the difference?

 

Yike!
man I 'd be impressed if the O-ring seals are still water-tight after sitting that long... ;p
Your irons will look like your water pump, not a good thing for needed free-flow of coolant on a rotary. Worse if you are going to keep it in the VW - Looks to me like efficient cooling has been compromised already with the install. If you pull the block apart, most machine shops now offer soda-blasting which is completely non-damaging to soft metals and the residue is harmless - unlike any missed sand if you sand blast the housings instead. Plus, soda won't eat soft stuff like bushings on a water pump.
'luck
Stu Aull
80GS
Alaska

 

Well that's definitely not something I was hoping to hear. Is there not something I could fill the coolant passages with and let them soak for a bit and then flush them out? Then put the engine back together and see if O-ring seals are still water-tight?

 

Somebody in this section said their 12a or whichevery was leaking coolent bad (tons of white smoke) he put some additive in that's supposed to seal block cracks? in piston engines I think, he said it hardly smoked after and posted like 8 months later and said it's still been fine.

Sorry I don't recall the products name, but if the engine runs half decent it may be alittle hope to use similar additives

 

The thread you are looking for is:

https://www.rx7club.com/1st-gen-archive-71/engine-coolant-seal-repair-maybe-750774/

Kentestu was the one who used a radiator additive that is made to seal up cracks in radiators and engine blocks. They usually are only a band-aid until it gets really bad, but his repair seems to have worked quite well, so perhaps these products work better for rotaries than boingers?

 

^Ya got it!

I'm thinking the OP maybe would like to atleast drive it for a bit (if it's even going to start) so the band-aid should be fine, looking at that engine it probably will need a rebuild soon :X

 

I my personal opinion, I say tear it down and inspect the coolant passages and water seals just to be safe..

 

I actually fear my 13b is in bad condition.

The coolent wasn't changed for years, when I half-*** changed it it was all thick, and the temps didn't drop with totally new fluid...

 

Sorry, I had a really busy week last week, so it took me a bit to get back to this.

But yeah, as cmanns said, I would at least like to drive it for a bit. And I know it does run. We did have the engine running for just a bit just to see if it would run. Then saw that the carb was leaking gas, so we shut it down and figured we'd start going through and doing a full tune up.

I'm guessing it would be a lot easier for me to replace the engine rather than to rebuild it? If I get a 13b out of a newer rx7, will the exhaust in the car bolt onto that engine being that this is an early 4 port 13b (or so i'm told) or will I have to have a new exhaust built?

 

Exhaust is fine. I built a system for a 4 port 13B and got to try it out on an FC 13B. The only thing I had to worry about was the intake, since it is way different.

 

...so if I get a 6 port 13b out of a later rx7, then I'll have to replace the intake? Well that sucks.

 

just rebuild that one to be safe port it while you are at it and oncei t runs just try not to kill your self. But on the serious note if you are having doubts as far as how good the motor is just take it out take it apart and see what yoou are working with before you go and spend money on another motor it just might be as cheap to rebuild yours and that way you would know what you got.

 

Looks like a two barrel carb. You can get a different manifold pretty easily. I, on the other hand, would prefer to rebuild the 4 port because I like them better.

 

You could try a couple doses of radiator flush to remove the rust. If the internals are too badly rusted, it will greatly inhibit the engine's ability to transfer waste heat to the coolant at the boundry layer. Since this engine is in a Bug, you'll need all the cooling help you can get. Cooling system needs to be in tiptop shape.

I would be worried that excessive rust/corrosion may have compromised the internals structuarlly, i.e., rusted through pinhole leaks and and corroded/thinned coolant seal grooves.