I was cleaning my engine today and discover something horrible there is a big Crack on the back right side of the Intake Manifold i don't know if it goes all the way or not but it looks like it does, I have no idea how long that has been there, but i haven't had any problems at all with the engine everything running smooth.

I am wondering how could this happened? Is it dangerous to keep driving my car like this? or can i wait until i can buy a new one?

Here is a pic...

http://fragranceexpress.net/fotos/Motor%20010.JPG

 

eek, did you torque it to proper specs? looks like that was done form torquing it down too hard ar too much at once or it was sitting on something making it not level....

 

To be honest i did not used a torque wrench when i installed this, i just installed by hand but not extremely tight, also i installed it over a year ago it is weird... so should i stop driving it? or what do you guys think?

 

Unfortunately, aluminum always cracks through when it is cast. However, while that looks like it was overtorqued and/or not torqued in order and in steps, it should run fine until you can replace it. In fact, you may get many miles with no problem.

 

if the gasket is sealed tight around the last intake port on that side it will be fine, those damn gaskets pretty much glue themselves together after a bunch of heat cycles. if its leaking, you can lean out a cylinder and cook a piston.

to check if its leaking, spray some carb cleaner around that area while the motor is idling and see if the rpms change. if it does, it leaks.

 

woof. That would keep me up nights until I replaced it whether it was causing issues or not.

I'd go ahead and replace it and next time use a torque wrench and tighten them in the proper sequence there Hercules.

 

One or more of the following are possible. Castings do not bend very well, so anything that would put that ear in bending is suspect.

Little piece of the old gasket (or carbon deposit) that did not get completely scraped off after removing the old manifold.

The new gasket did not wrap completely around that bolt hole, or had very little "edge distance" around the outside of the hole.

Overtorquing. Upon enlarging the picture to full size, it does look like the corners of that hex head of that bolt were starting to round off. Did you initially have any problems with rough running or poor idle when you first installed this manifold?

Little raised burr on the gasket face of the head from prying the old manifold off - especially if you tried to lift the manifold but missed a manifold bolt or two the first time (never mind how I might know that).


Norm

 

DOH!

Nothing like the voice of experience is there Norm...


hahaha.

 

gmata,
That should be a fairly simple fix, especially if it is an aluminum intake manifold. Even if it is cast iron, any decent shop should be able to fix it using a nickle (ENIFe) electrode. If it is aluminum, it can be easily repaired using the GTAW (TIG) process. Make sure that whoever repairs it grinds out the crack to a vee configuration and back welds the other side afterwards. Hand filing the machined surface will make a suitable interface for your gasket to seal.

 

fastbackford - If experience doesn't pound something into one's thick skull, I guess there isn't much hope.

Almost totally unrelated tip #1 - don't forget to remove the fuel pump and its pushrod when swapping SBC cams.


gmata - that crack might not have happened during the actual installation or during re-torquing/retightening when you would almost certainly have seen it. A couple of heat cycles afterward might have been what did it in. It might be possible to guess how long it's been fully broken based on what the crack surface looks like (coloration). Like others have said, if it doesn't seem to be affecting the way the engine runs, the port is either not leaking at all or at most very very little.


Norm