Skip to main content

Closed8 replies

Engine rebuild problems

B bdMember
The engine in my Pantera has a little over 1000 miles since a total rebuild. The rebuild included a .030" over bore, new rings, bearings, pistons, etc. Since the rebuild, the rings (or whatever) never seal or seat until the engine is thoroughly warmed up. The engine will blow clouds of blue smoke under load until it warms up. The engine idling when cold isn't too bad. Any ideas why the rings or pistons don't seal until the engine warms up? The pistons are Keith Black Hypereutectic and the rings are Speed Pro. I have read these pistons don't expand as quickly because of the silicon content. I miced the pistons before installing them and set the ring gaps all to KB specs. Any input would be greatly appreciated. I am thinking of pulling the motor back apart and installing forged aluminum pistons.

[This message has been edited by BD (edited 04-15-2003).]
Original Post

Replies sorted oldest to newest

J JR (Guest)
I had basically the same identical problem and it took almost all last summer to figure it out. The problem was a leak in my intake manifold, when the car warmed up it was ok.Part of the problem was I didn't realize that my heads were milled and my intake also had to me machined to match up.If you pull the intake and see any oil at all on you're gaskets you are sucking oil into the combustion chambers via the intake valves.Good luck it's an easy fix if you know where to look.
B bdMember
Thanks JR and FordGT for your comments. I have pulled the intake off twice thinking it was being sucked up into the intake port. I didn't see any oil on the gasket. I was wondering if you use the "Turkey Tray" under the intake? A knowledgeable source told me I didn't need it. I am wondering if I do now. I have been using straight 40W conventional oil per my cam manufactures recommendations.
U ufmbagrad (Guest)
Whereas I can see leaving the "turkey pan" out will cause no issues with sealing - I would add that the "turkey pan" serves more to keep hot oil from hitting the bottom of the intake keeping your air intake temp cooler.

The primary issue is merely having a good seal between the intake and the heads in the first place to eliminate vacumn pulling oil into the intake charge from the lifter valley. Get a good intake gasket as previously recommended, double check to make sure that if the heads and/or block were milled that they were not milled too much to cause a change in the alignment of the intake and head. If there is a big discrepacy of misalignment then even a gasket will not work and you'll have to work on that issue first.

Just a few cents to throw out there.

Dave
U ufmbagrad (Guest)
Last thing I will add is to consider the work on the heads... Were new valve guides installed? As well as premium valve stem seals? Even while installing new seals you can inadvertedly tear one while sliding it over a valve stem. This can allow oil to seep down the valve stem while cold and giving you smoke when it gets sucked into the chamber.

Dave
bosswrenchbosswrenchMember
"Clouds of blue smoke" means oil is getting into the combustion chamber. There are two paths: from above via bad valve-guide seals or a plugged drainback hole so oil fills the rocker cover to the brim & runs down under the stock umbrella-seals. You seem to have taken care of intake mainfold gaskets, but this can be checked by pulling the plugs before the engine is warmed up; serious oil-burning will give an oil-wet plug in the bad cylinder(s). The other choive is bad rings that allow oil on the cylinder walls to creep past the oil control rings. Without being there, I can't diagnose further; I've seen brand-new std-bore pistons in 0.030-over bozes, mis-marked rings, etc, etc. Keith Black is a good brand, but like all cast pistons, they require a tight fit to the bore, while forged are tolerant of as much as 0.005" of slop.
Views: 208
Post

Membership Required

We're sorry. You must be signed in to continue. Sign In or Register
×
Are you sure you want to remove from your Block List?
×
Loading...
×
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .
×
Link copied to your clipboard.
×