150K on the clock and the PO supposedly just rebuilt the head and checked for cracks in it. However, motor is burning oil and I get a high rev on startup with a pretty good puff of smoke. Is this normal to the RENIX motor? Could it be burning oil on startup?
Thanks,
Jamie

 

How high is high rev? and ya if its puffin blue smoke its oil being burnt. The oil is leaking past the valve guides while the engine is off which is why its smoking on start up. same thing if it burns it while running or bad rings.


Dont be alarmed. My 92 was like a mosquito fogger lol. The only time it was bad was when I was puttin around the trails. Normal driving it was ok

 

Valve guides are suspect for some smoke upon "startup".

Exactly how much oil do you use in 3,000 miles?

Never a bad idea to run a compression test on all cylinders. A good "snapshot in time" of the internal condition of your engine. Perform a dry test and then a "wet" test. SEARCH for the how-to.

The compression spec for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

 

its reving to 2500 or so on start. I'll do a comp test and let you know. Will a comp test do it or do I need to do a leak down/

 

A compression test is where I would start. Don't need any specialized equipment for that except for a good quality gauge and a few teaspoons of oil.

 

Alright, did a compression test. All cylinders were right around 140-150 with the exception of #6 which was down to around 125. IT is burning a lot of oil though and also drinking some coolant.

I left it running today when I went into the store and when I came out, it was hazing pretty damn good while idling there.

Where do I look next?

Should I do valve stem seals with a spring compressor?

Leak down test?

TIA Jamie

 

You *could* try running some seafoam through the intake to temporary alleviate the problem, but it sounds like the valve seats are toast. I would do it anyway, because something could be sticking open. Carbon buildup could do that, but don't get your hopes up

 

what color is the smoke??

 

It is a gray smoke. Looks like burning oil.

 

In my experience, burning oil out of a car was a bluish smoke, but I may be wrong. Burning oil has a VERY distinct smell...