TPI-Formula350-

ok so I had a new 385 cu.in. engine built. I had my Brodix 200Ik heads with 2,000 miles installed on that short block. After a few hundred miles the engine started burning a lot of oil with blue smoke. I was also fouling 3 of 4 plugs on the passenger side. This was with only 500 miles on the new engine. Also saw a gold color in my oil. So I pull the head and the valves are all loose,wasted guides. I have since had the guides on both the heads replaced. I asked my engine builder if he may have messed up with geometry, he said no he checked and it was fine when he built the engine. I'm putting it all back together tomorrow but I keep thinking this must have happened for a reason?! I dont want to have the same issue happen again on another 500 miles. I'm not sure it the block was decked but the heads were milled .005. I looked at the pushrods and they are all 7.300". I have colored the tops of the valve stems all with a marker to be certain that the rocker tip is running in the center when i assemble it...Any ideas what may have caused this or anything I should check so this doesnt happen again??

327sleeper88

sounds like the guide were too tight out of the box, and/or not lubed up right during assembly. if your mechanic did the valve job the stem to guide clearance should be right.

mlynch001

Bronze guides? you are sure that the geometry is correct? Usually guide wear is a result of dirt or grit left in the guides during machining, entering the air intake or excessive side thrust due to geometry issues.

TPI-Formula350-

yes, the Brodix heads came with Phosphor/Bronze guides...My engine builder just replaced them with new Bronze guides. Am I correct that coloring the top of the valve stem with a marker and making sure the rocker roller tip rides the center of the stem then the geometry is correct?

mlynch001

The geometry is correct when the rocker tip stays in the center of the valve through the complete valve opening and closing cycle. The trick is to avoid geometry that causes the rocker tip to sweep excessively across the top of the valve stem. So, the mark on top of the valve SHOULD be centered and narrow as well.

I am not impressed with bronze guides as far as durability. I used two sets and life was short on both. Replaced them with steel/iron guides and problems stopped. Maybe just a bad experience? Geometry was NOT the problem with these heads.

Another problem that I have seen is valve seals that are "too" efficient, especially on the exhaust side and do not allow adequate lubrication for bronze guides. I try to keep oil flow to the top of the engine to a minimum so that the seals have less oil to contend with. I never like to see an engine that "floods" the rocker arms with large amounts of oil. Just enough oil to lube the rockers and cool the springs is all I want to see. I NEVER run positive seals on the exhaust, just umbrella type seals. My engines do not smoke on start up and do not use excessive oil (1 quart/2000 miles). You must have some lubrication at the guides (especially the exhaust) or the guides will not live. Are you having problems with the Intake and Exhaust guides? What do your valve stems look like when you pull the heads apart? Are the valve stem diameters worn under size or do they exhibit signs of galling or black stem carbon buildup? I have also seen guides that were not thoroughly cleaned after reaming and the microscopic cuttings left in the guides caused premature wear issues.

TPI-Formula350-

thanks for the info. I put the heads and lower intake on today. Tomorrow i'll put the runners/pleanum and rockers on. My valves showed no signs of wear just the guides. It seemed to be all 16 guides and they were loose in every direction. I'll def makes sure the rocker tip is centered and has a narrow path on the valve tip.

TPI-Formula350-

I have the engine 95% together and I adjusted the valves. After coloring the tops of the valve stems with a marker and bumping the engine a few times I removes an Intake and exaust rockers from #1 on the driver side and #2 passenger side. The rocker tip woreout the area on the tip of the valve where they were riding. It wasn't perfectly in the middle but VERY,VERY(maybe off center by 1/16") close. The area the rocker tip was riding seemed to be approx. 1/8" wide, So I'm thinking my push rods at 7.300 are the correct length. Sound good to you guys??

TPI-Formula350-

bump

Damon

That sounds plenty good.

I've had valve guides wear out for inexplicable reasons, too. In one case it was a single exhaust valve guide. Wore out so bad I could wiggle the valve back and forth almost 1/16"!! And that was a set of heads that had been in use for several thousand miles with no problems up to that point. All others were fine, as was the valve itself. Had it fixed and it ran thousands more miles without a problem. Go figure.

JakeJr

If you CAREFULLY read what CompCams, and others, have written about the movement of the roller of the rocker arm across the valve stem tip you'll see that the roller does not remain centered, nor is it supposed to. The roller moves inboard, center, outboard, center, etc., as the valve opens and closes. This is how it is supposed to work.

What you're looking for is the narrowest movement indication - where the minimum amount of marker coloring is removed. That results in the best average centering of the roller tip over the stem and reduces the amount of guide side loading to the greatest amount possible.

As a rule of thumb, when the valve is at HALF LIFT, the roller of the rocker arm should be centered over the valve stem tip. Yet it won't be centered when the valve is at other positions positions other than HALF LIFT. There are so many differing views and opinions on this it's easy to get confused as to who to believe is correct.

The full explanation and diagrams are shown on Comp's website, in their catalogs and is also used in several magazine articles as reference to their readers. Although you'll find other explanations for the same thing, Comp's procedure and recommendations are quite often cited by others as authoritative.

Jake