My first engine diy engine out

OK then if you hollow out the cats you will have a 'check engine' light issue. The O2 sensors after the cats are used to measure 'catalyst efficiency' or how well the catalytic convertor's are working. This ensures that the emissions remain within specs for the lifetime of the vehicle. Just as the pre-cat O2 sensors send information back to the ecu reporting on the previous combustion event which allows the ecu to make fuel trim modifications, the post-cat O2 sensors send information back to the ecu regarding the oxygen content in the after catalyst gases. The signal of the pre-cat O2 sensor ranges from approximately 100mv to 900mv in a typical zirconia sensor and this signal changes quit rapidly sometimes upwards of 15 times per second depending on a number of factors. The post-cat O2 sensor signal usually hovers around 450mv and is quit stable (meaning little change) with a properly functioning catalyst. In my experience you will get a catalyst efficiency code (usually a p0420)if the voltage fluctuates beyond about 350mv and 650 mv during the time that the catalyst monitor is run. This is usually at idle when the engine is warm and the vehicle is in closed loop operation. In other words if you hollow the cats out you will most likely get a check engine light.

However I need to ask the question, unless you are looking to run your vehicle on the track only why hollow out the cat's? In my experience catalytic convertor's present less impedance to exhaust flow than the muffler does. I of course don't have a ton of F-car experience but have done enough other performance work on other brands and for a vehicle driven on the street unless the owner is really serious we leave the stock cat's in place.

Just my 2 cents worth.

Jamie

 

Thanks Jamie. I think the tubi's look cool, but I have stock in stock so I guess I will put those back in. I also figured a slight uptick in performance. Thanks for the info.

 

No problem, happy to help. I am starting my own car today and will confirm that it has a Tubi exhaust and still retains the stock cats. Although I will be removing them to have a good look inside. Have fun.

 

I have 6 bolts to remove now. I have put every bolt back in it's place of removal. I did not need bags or anything for the storage for a single bolt. I feel like I've missed something. I guess I'll find out during the installation.

 

Touchdown!!! It's out thanks for the help. Pics Tomorrow.

 

Again? Now you are up 14-0 ....looking forward to the pics.

 

right you are Mike, but this one will be alot more reasonable.

 

burnt exhaust valve. Are there any secrets that I should know about this operation? Installing it that is...

 

I need a new camera so I apologize for no pictures ( they are coming) but I am wondering why I have severe burnt carbon on my 2 affected exhaust valves and one of those valves is burnt through a quarter inch of the flange. (2 exhaust valve ordered). Does anyone know what would cause that?

 

Ouch sorry to hear; I just heard of another local guy who had something similar. I would suspect timing being off, causing it to run too lean (high temp). Or I think I've heard that bad exhaust manifolds can also cause the lean condition and high temps...

 

I'd have the injectors checked too. You could have a partially clogged one causing a lean condition. There was another member that had his checked recently. You should be able to find the info with a search.

 

Here are the much anticipated engine pictures I was telling you about... Let me know what you think
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I'm assuming you had a valve guide issue?

 

No Ernie, it looks like the guides were done however, I don't think the valves were properly lapped in and I had one burnt valve and looked like one on its way so I've had all the valves reseated. I should have the heads back next week.

 

OK. I have the 2.7 in where the 5.2 was.
I have several questions on the home stretch.
1. there are 2 electrical connections that look similar to the ecu connectors where I have no idea where they go and the manual is not clear.??????
2. the exhaust (capristo race muffler with the two bypass valves) doesn't make sense at the connections. They don't have the mating collars and it looks like I have to custom make a collar to mate between the cappy and the straight pipes?.
3. can I just hook up the front O2 sensors and leave the rears completely unhooked?
4. Car turns over but does not start. Why?

BTW the heads were not done yet on the 5.2 engine but should be back together soon. I;ll post all the pictures tomorrow.

 

here are the pics...

I know how to fix the last one...
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I will definatly DIY the last one for you. Whooooohoooo!

 

^ Thanks but I can handle that one... That engine is in the car as you can see.

1. It is the 2.7 it is not clear in the manual what those 2 electrical connectors are for.
2. The exhaust is a capristo race version that I am connecting to the straight pipes and it is not the same as the cat hook up. So I can build a custom coupler but I'm curious if there is a standard coupler or do I have to make one, or has anyone got a better way than making a coupler?

 

One has to wonder what was on his mind at the time of posting.
I think that may be a PC picture equivelent of whats called a Freudian slip

 

The piping connections look like V-bands. Check this link and see if that's what they are.

http://images.google.com/images?q=v-band%20flange&um=1&ie=UTF-8&sa=N&hl=en&tab=wi

 

Normally, I would suggest "if it ain't broke, don't fix it", but, since you have it out, be thorough.

 

Thanks Tim, that's looks like it will work for the exhaust.

Now just for those mystery plugs...

 

Is this the exhaust clamp you're looking for?

http://www.ricambiamerica.com/product_info.php?products_id=261264

 

Did you replace a 2.7 motor with a 5.2?

 

I replaced my 5.2 with a 2.7 and am running completely catless with a capristo race exhaust with the 2 external bypass delete. I intend to have it remapped.