Hi People. I have an issue with a motor that has a set of AFR 210 LT4 heads on it. My customer and fellow forum member is telling me that he is using up to 2 quarts per one hundred miles if you goes out and runs the car HARD for those 100 miles. From what I have seen and heard that their is an issue with the AFR heads returning oil to the sump. I know and my engine builders feel that there is NO WAY that the engine can pass that volume of oil past the rings. My feeling is that some how its passing the oil through the valve guides. The last time I had the engine apart the heads were inspected and new viton rubber seals were installed as a safety measure. However its still consuming the oil during spirited driving sessions.

Glen has since sent the spark plugs back to me for inspection. I don't feel that there is that kind of consumption based on just what I see on the plugs. I feel that the oil is being sucked in through the valve guides during high RPM decceleration and blown out throught the exhaust. If this engine was using that kind of oil and actually burning it, the plugs would have fouled long ago.

Now here is what AFR tells me. With out acknowledging any actually problems with their heads. They feel that because we have a high volume high pressure oil pump in the engine. That oil is being pumped into the upper part of the engine (heads) and because it can't return as fast as its being feed that oil is pooling in the valve spring pockets and being sucked into the cylinders and blown out under high RPM decceleration conditions.

My question is, has anyone else experienced this kind of problems. I have taken the engine apart personally, and checked the internals out myself before the machine shop replaced the rings and honed the cylinders for the second time. New valve seals were also installed at that time and the engine continues to use oil. My own car has a similar engine with AFR 195s but I have a stock volume oil pump with a high pressure spring.......so any one out there with issues such as this??

 

Tom, I've got "hybrid" AFR's, in that they're AFR/TPIS....187cc....I go thru about 1 qt every 1,000 miles. Some say its acceptable, some don't.......personally I would prefer to see much less, but I can easliy live with it.......In my case I have a Melling high volume oil pump (not high pressure).........It could be possible that this is causing a similar, milder oil "use" condition as you're describing, since the high volume characteristic also adds a bit more pressure.....The only way I could confirm is to switch to a standard stock oil pump, which is something I've been considering for awhile. Then again, it could be that I'm also running forged pistons, so I'm not certain what's causing the 1 qt/1000 mile oil loss. I see no indications of oil spots on the rear fascia or at the muffler tips, so it doesn't appear any oil is being "blown out" the exhaust.

What caused the decision to go with a high volume AND high pressure pump on your end? Why not just go with the standard stock pump?

In my case, my engine builder decided to put the HV pump in, and never consulted me first. I probably would have told him "no".

 

A quart every 1,000? Ouch!

Here is a thread I remember reading a while back.

http://forums.corvetteforum.com/show...+spring+pocket

 

I have a Melling 55HV, AFR/210 on my 406, they seem to drain back OK, I get @ 50-PSI oil pressure while cruising

 

Ummm, Interesting. I have a 74 Camaro that will run around 8000 RPM. I put a big block high volume oilpump in it, and 9 quart pan. It's been quite a while ago. My heads are stock GM with 2.02 intakes. I noticed at high rpm after a run through the quarter, the car looked like it was on fire. I was checking everything. Problem was I wasn't thinking when I installed that big pump, of course that was in 1984. I still have the car, and I always blame it on the rings not being seated. Well from then to now, if I had it to do over again. I would run the stock pump, with the bigger pan, and extended pick up. Small block chevy's are not known to have lubricating problems. I still have the car, and I'll bet that it is doing the same The engine you speek of is... Just a thought...

 

Unfortunately I am beating you with 300 miles per quart oil, hv pump,
stock heads. Talk about nightmare.

 

Hey,,, now dont get me wrong, I think the oil return on my heads are marginal at best.

 

Do the rocker studs thread into the intake runner like some heads (Pro Topline, RHS) and if they do did you use thread sealer on them?

 

I have TPIS AFR heads also and they use no oil. My car has 82000 miles and uses no oil.

Fred

 

Stock pump?

 

Could it be sucking oil into the into the intake? had this problem with a 406 in a mud truck some time ago. I most certain I did not have the same heads though.

 

I really doubt it, the intake is well sealed and as far as I know there is no trace of oil in the intake when looking into the inlet. I will know more when I get the car back. I personally sealed the intake using the GM LT4 race gaskets and a lite coating of "the right stuff" RTV which I am sure would have sealed it well.

 

Tom,

If the heads were sucking that much oil thru the seals, wouldn't the valve stem be coated with oil upon visual inspection? I would think that there would also be some sign of oil baked on the valve stem.

Are the seals the standard GM set up(?) intake with the two metal bands and the mickey mouse exhaust "umbrella"? Perhaps intake seals all the way around would help.

I think Tim (CABOBOY?) built the 421 CI (from past posts) and had the larger AFR heads. I believe that he had an additional groove machined at the base of the heads to increase the flow of the oil return and keep it from pooling. Would this be a possible solution? Could the oil return holes also be enlarged?

I have run high volumn oil pumps on several 350's without oil problems. But they were always HV low pressure. Does the engine really need the high pressure?

My next guess would be the intake, but knowing that you used the Right Stuff sure rules that out.....unless the engine was overheated and the intake warped and you are pulling oil from the valley. Is the PCV valve working correclty, no kinked hoses? If the car is driven with SPIRIT it could be pressurizing the pan and valley, forcing oil thru the intake where it connects to the heads. This might explain clean plugs.

Any idea of what the exhaust manifolds look like? That might narrow things down to a side or a couple of cylinders. I would also think that the cat has to start reacting to this much oil.

You have probably thought of all of the above already.

John

 

Tom,

I have also heard that some of the earlier AFRs have oil return problems.

 

Tom,

I had AFR 195cc runner heads on my L-98 race motor. Suposedly AFR addressed the oil retention problem with the new LT-1/4 design. I had no end of grief with the AFR heads inability to flow oil from the valve train in the heads back to the pan. The oil returns at each end of the head are located considerabley higher in the AFR head than in the stock heads.

I had to build a closed valve cover breather system and vent tank to keep the oil from being spewed out the breathers. I also added (2) -8 return lines on each head to drain oil from the valve covers back to the pan.

This is not a new problem for AFR. Their literature for the new LT-1/4 heads aknowledges the problem and states the new design addressed this problem. Maybe not?

Larry

 

I have AFR 210 cc rr heads and my car pukes oil after revving the motor up. Watch the end of this video for an example.

http://video.ls1tech.com/video/7b3b3...3400b2d579.htm

still trying to figure this out.

 

We used a 3/8" ball end mill to trough the bottom side of the valve cover rail on almost every set of AFR's we ever used for this problem. They're great heads but the drainbacks and the bottom valve cover rail were of a poor design. Milling the trough allowed the oil to drain back and also not sit on the valve cover sealing surface (which we constantly had leaking) or pool in the spring pockets. From what I've gathered from Tony Mamo at AFR they've addressed this on their new castings. I talked with him last year at SEMA.
-Jeb

 

I have AFR 190 heads, and a high volume oil pump on mny L-98

I have the same issues. 100 mile drive, oil is low.

I took them apart 3 times. replaced the seals. resealed the rocker studs. and pretty much gave up. debating on adding drain lines to the valve covers, or getting those cnc brodix heads heads.

 

Hey Jeb,
Do you have any pics of your drainback correction. I am thinking of doing something like that this winter on my 195's to help oil drain back to the pan.
Jim

 

I don't have any on this computer and don't remember taking any pics but I do believe I have a set of AFR 190CNC LTx heads at my shop that we did this too.. If they are I'll take a pic and post them.
-Jeb