Hello.
I managed to get the Ez- start separated from the engine, & noticed a crack on the inside where the exhaust header attaches. There's a similar crack on the other side. I managed to unseize the Traxxas 2.5 engine yesterday afternoon using a heat gun & was really happy about. I see these cracks now & it has me concerned. I've got my ebay Traxxas rustler apart for a good cleaning, so I can make a shopping list for what I need.
Thanks

Your pic is blurry. Where are these prospective cracks?

Sorry for the previous pictures. I went to a hobby shop this afternoon with the engine asking about the crack I noticed where the exhaust header attaches too. It is a crack as the shop employee pointed out & he said that I shouldn't worry about it. I have looked at Traxxas engines on ebay and other rc cars for sale which include an engine, as rc car engines at the hobby shops where I live are out of stock. I hope this helps.
Thanks

That looks like a casting flaw to me; if it were a bonafide crack, the crack would manifest itself through the whole surface. I don’t see evidence of that; I see what appears like a superficial scratch in the internal surface only. That said, if it is indeed cracked all the way through, and the dirt and grime is masking it, replacing the crankcase would cure the trouble. I happen to have several 2.5 crankcases that I will never use. If you want them, you can have them for the cost of shipping.

edit: I know I have 2 or 3 crankcases, but I can only find one at the moment. Used bare crankcase with no bearings. The image uploader doesn’t work very well, so I used my image host to post these.

I cleaned the outside of the engine this afternoon and saw a scratch unless this is another crack. I looked at the anomaly further on the way home, & it starts at the top then goes down to where the backing plate would be. I have looked into a Traxxas parts car on ebay which includes an engine also.

I don’t see anything alarming other than the corrosion. If the manifold leaks when you run it, put a little RTV around the o-ring (looks like your case is missing the o-ring currently) before cinching the screws down. As long as it doesn’t leak, it should be just fine.

I spoke with my brother recently about the engine on my Rustler sending him the photos of the "crack " & the other anomaly, which I included in this forum post. I could tell in his reply that he wasn't too happy. I sent him the ebay link of the parts car I want as it includes an engine and tuned pipe. He replied saying " out of the 2 cars it's possible that one will work " He suggested that I get a " working " car ie: brand new rather than fix a car. A hobby shop close to me has a Traxxas 2wd Slash,along with a Jato 3.3. The store also has a couple 1/5 scale Losi's which I'm not willing to spend $1500.00 plus tax on. The other hobby shop has an rtr Traxxas Revo & an Associated rc nitro kit. I'm leaning towards the rtr slash, as I can use rustler parts if something breaks plus it's also a no- Brainer buying an rtr new.

https://www.ebay.ca/itm/116692915160?

Here's the parts car I want. I'd like to fix both cars yet I could probably do it one at a time. I'm on the fence about this one, as my brother mentioned in his reply a "big investment" knowing right away he was talking about the engine.

I bought a used rc10gt off ebay one time. The guy said he'd seen the engine run. When I got it the engine had two of the head bolt holes stripped out and had a tap broken off it one of the back plate holes. I got it running but I had to buy a new block for it. Couldn't see any of that in the pics in the add. Cured me of buying used motors on ebay. Don't expect an ebay motor to run. That's what I've learned. Only took once.