knock in my engine what is it? HELP!

[fivepointhustla]

I have an 86 fastback 4spd gt.....

I had a loud knock in my engine that was barely audible at low rpms but picked up at higher rpms. So I swapped shortblocks with an 85gt, I also installed a 260H K-kit from comp cam. So that's new lifters, cam, seals, locks, cam gear, springs and I got new comp pushrods too. I had the heads milled 0.015 and I replaced every gasket. Even enlarged the water holes on the head gasket just like the GM performance manual says (I have if you need), and I also gasket matched the exhaust ports as well as my exhaust manifolds.

Now with the 85 shortblock and all my mods the engine has a knock with a different pattern. Before the knock had no certain rhythm. Now it DOES have a certain rhythm AND it pours out a ton of smoke. I try to rev it to red line and it won't go past about 4500 rpms.

With the 85 and 86 the engine started up fine as if nothing was wrong then the knock would started.

I would really like to fix this so could anybody please help?

[Doubt_Incarnate]

was the shortblock used?
Where did it come frome?
what color is the smoke?
did the 86 smoke?
hows the oil presure?
is the timing right on the cam?
the ignition?
if you have a mechanics stethescope, listen to the heads to see if the initial noise followed over, a problem in the heads might have been all that it was.

[fivepointhustla]

The shortblock was from my 85gt that reads 90,000 miles. The 85 had no problems before I blew the clutch out. My friends say it is blue smoke, but it looks thick and white to me. From what I hear that means I am burning gas. No the 86 did not smoke. The oil pressure was good in both engines before the 260 cam, after the cam the oil light would come on at idle then pick up quickly when I rev'd the engine. The timing marks are lined up, the comp 260 has a 4 degree advance in the grind. The ignition we did by ear and it sounds pretty solid.

It starts like it did the day I bought it, but it just knocks and smokes now. I am very discouraged now that i spent almost $800 on a piece of shit when I could have just bought a new engine from napa for 250 more. I just love my fastback tooooo much to sell it. 3.4 might be my next avenue, but it will have to sit for a year if I don't get it running right.

[Doubt_Incarnate]

thick and white is coolant, black or dark is excess fuel, white with a blue tint is oil.
either way it souds like you have to tear it apart to find out whats going on. it seems odd that you moved the stuf from one block to the other and still had problems, worse problem actually. maybe the bearings are shot and thats the knocking, but that wouldnt smoke. i'd pull off the heads and check to see something didnt fall in where it shouldnt be, and check the cylinder walls for scoring, that might let you know if a ring cracked. the rev problem seems like either your not getting the spark right, timing, or firing order, or there isnt enough lube to let it wind up. maybe if something disapered into the intake, it stuck a valve open and that would make an ugly condition.

you could just pull the valve covers first, and turn the engine over slowly without starting, and watch closley the rockers to see they move properly. if thats good, you would want to take the heads off to see whats goin on in there.

[cobraCMDR]

verify ignition timing before tearing it out.......I'm assuming this is a 2.8.......they do very strange things if not timed properly.

[fivepointhustla]

I haven't been on here in a while, but I thought I had the timing set but will check. I start it every once in awhile just to keep to juices flowing. I'm thinking about a 3.4 swap or a 3.1 swap. They cost the same pretty much from all the local stores. I have a compcams 260 and was thinking that might be it or the heads but i don't know. I kicks out white smoke, I put brand new head gaskets on it too.

[torq455]

did you inspect the heads for cracks, replace valve seals? also wondering if putting the 260 cam in, the bearing clearence is correct. if the short block ran well, the knock might be the cam bearings banging, and the smoke may be a cracked head. some older 3.1's had a tendancy to crack the boss on the passenger side by the firewall. maybe it went all the way through to the combustion chamber.

[fivepointhustla]

right now I am in the process of swapping a 3.1 in. I gave up on the 2.8.

[sharkey]

now you say the oil light comes on at idle. to me that sounds like a spun bearing. another thing is the cam. did it fit tight in the bearings???

[fivepointhustla]

got the 3.1 in and running for about 3 weeks now. i also put the 260 in. I just added a under drive pulley last week that thing is the shit.

I am running my stock fiero pieces and it runs rich is this normal?

[torq455]

no. are you using the stock chip? if so, you might wanna get a tuned for that cam one.