Chevy pickup blowing blue smoke and misfiring

maureen1904

Chevy pickup blowing blue smoke and misfiring

Unread post by maureen1904 » Fri Aug 06, 2010 11:31 am

My oldman has a: 1975 Chevy Pickup 4x4:/shortbed/ that had a << 350>>/"388 Stroker Motor" (or 383 i don't remember the #'s)// (A 350 bored out! Sheesh)- put in awhile back... Yesterday he drove it about 40+ miles for materials and was returning when he was almost back at the jobsite when he had to slam on his brakes; Ever since that very moment it has been blowing "BLUE Smoke" and missing really bad...what's the problem? What steps would you take in the repair/diagnosing/whatever...in reference to this problem...Thanking you in advance for ANY input ANYONE is able to provide me with!!! So just know that " You Rock & U know it!!!!" :!: ;)

willwildy
Posts: 20
Joined: Fri Aug 13, 2010 10:59 pm

Re: 1975 pickup blowing blue smoke & missing!!!

Unread post by willwildy » Fri Aug 13, 2010 11:17 pm

It's tough to tie him hitting the brakes in with a smoking problem so I am going to give you some common cause of smoking on the V-8 Chevy.

#1 Valve seals. At the top of every valve there is a rubber seal that prevents oil from running down between the valve stem and the valve guide. When these become degraded they can cause smoking (especially on startup). They also cause a buildup of carbon/tar on top of the valves which restricts air flow into the engine degrading performance.

#2 PCV valve stuck open. This allows an open pathway between the valve cover and the intake manifold. Allowing oil and air to be sucked into the intake.

#3 Valve cover baffle broken. Again tying into the PCV if this baffle is broken or has been modified it allows engine oil to be sucked in the intake causing blue or whiteish blue smoke.

#4 Taking the missing into account it could be you broke a ring on one of the cylinders. To diagnose this run a compression test on all the cylinders. Compression testers are readily available at most auto parts stores for about $30.00 to use one follow the directions on the packaging.

IF you write back with results from a compression test I will try and help you some more.

Bill
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