I pulled my AFR heads off my engine today looking for a causeo fmy severe blowby and I noticed that the front 4 exhausrt ports where white while the back 4 where solid black. I have 1K miles on my engine and the tops of the pistons are covered in carbon. I also noticed that the front 4 inlet ports on top of my HSR intake are still pretty much new looking while the back inlet ports on top of the intake look yellowish like they are fuel stained or something. Oviously, Im running a bit rich if there is carbon build up on the tops of the pistons after only 1K miles but what gives with the discolored exhaustr ports on the heads. Its like the front half of the engine is running lean and the back half is running rich. Can this be from the design the HSR intake and its basically feeding the front of the engine more air then the back?

 

if you have blow by it is coused by the rings not sealing has nothing to do with the heads. are you shure it is carbon and not oil burning on the top of the pistons? It could be the rings seated on cylenders with no carbon. I hope you did not use eny moly lube or synthetic lube on the rings or cylender walls during assembly as this will somtimes prevent the rings from seating in properly. Did you do a compreshion and leak down test befor you disasembled it? Id would help a lot. If you actualy had a leen condition it could have bean from a vacume leak or an injectore problem but it is unlikely that it damaged the rings enuff to couse blow by. Did you folow a brake in proseedger on your new eng.? I would be happy to help If you have more qestions.

 

Somebody failed spelling lol

 

scot, thanks for the help but you have really got to learn how to spell.

 

Ah... you pulled the heads before you did a compression or leakdown test?!?

No vacuum reading? Shame, you might have to waste a set of head gaskets unless you are already planning a rebuild. What were the other symptoms?

Are all the piston tops coated in carbon? Have you pulled the plugs to read 'em yet?

 

I did a compression test and all 8 cylinders where between 185 and 187. I then did a leakdown test:
Cyl 1 38%
Cyl 8 60%
Cyl 4 38%
Cyl 3 38%
Cyl 6 33%
Cyl 5 40%
Cyl 7 38%
Cyl 2 35%

air was hissing out the dipstick on all 8 cylinders.
The plugs have been checked at least 10 times since I built me engine and everytime I checked them, they had a goldish tint to them. Nothing looked abnormal.

 

My apologies for my spelling. It’s my only fault. HA.
From now on will use word for a spell check before I post.
Most of the time ms word can’t finger out what I am spelling ether.

 

Wow. That bad with a decent compression result? Odd. Sure it was going into the crankcase? Any other issues? Gas in the oil? Sure you did the leakdown right? Planning on a rebuild now? Ouch.

 

I wouldnt say a prob like that is due to the intake. To many use it with no problems. It does seem like you are lean on the front. But not neccesarily. I think i would check all the parts for fatigue, make sure you havnt eroded away a lot metal on ur piston walls, see taht they cross hatch is still there(you might need to take a mic to them and check thier actual diameter vs. machined diameter), take a look at your vavles and make sure there not bluish or discolored at the stems(possible sign of overheating that could result in a loss of shape or embrittlement). Prolly wouldnt hurt to check the heads for trueness, u just need a straight edge and a feeler guage. Might as well check the block too. As for the hissing, the rings have small gaps between them so you are going to loose air past them, more so while cold then hot. The more your rings wear the large that gap becomes and the fsater the leakdown is as well.

If you're really concered about your heads, i think there are rig's availible to bolt to the head with a head gasket while its off the car and pressure them up through the spark plug hole, but rember they're not hot when you do this so the valve seal might not be as good as a warmed head. I'm sure there are specifications it must fit in for this kind of test.

It the heads are good, no pistons are burned, and the cylinder walls are good, then the rings are prolly fine, put it back together.

Put a heat gun on the front cyclinders and see how hot they are. My last stocker street motor(650 cfm 383 stroker stock 94 350 truck cam @850 rpms 420 ftlbs of tq, fun) measure about 470 degrees F on header surface temp after going for a good drive. This meausred with an infrared heat gun from about 6 inches. Ambient temperature is pretty irrelevant for this kind of equipement at that range so it can be considered accurate within 4-5 degrees. They were all within about 10 degrees. I'd say if you're over 600 degrees, you're prolly starting to glow and you're almost deffinately lean.

As for fixing the prob... that's to the programming whiz who designs your chip i think. I can tune a carb, but i havnt yet tuned a chip. I'm out of the 400 dollars.