HSR intake oil leak mystery.

Like the title said, my intake likes oil and from what I found playing with the ''search'' option on Thirdgen.org I'm not alone. Nobody seems to know why this is happening.

I'll try to make the story short.

- First when I got my engine running for the first time I did it on an engine stand with a carb intake and had no leaks around the intake ports when I removed the intake.

- My oil consumption started when I installed the HSR intake (1 quart every 300-400 miles). I had my PCV installed and I could see the inside of the plenum coated with oil.

- I then installed a catch can inline with the PCV. It did it's job but the plenum was still coated with oil.

- I removed the intake for the first time and found out that the contact pattern impressions of the intake was not good and that the first 1/3 of the bottom of the gasket was wet around the ports. The gasket was only slightly crushed on the bottom. After some measurement I found a gap of 0.008'' at the bottom of the port between the intake and heads.
After comparing the angle of the intake with an other SBC intake I concluded that my engine set up and not the intake was the problem.
I then had my machinist removed 0.018'' of materiel from the TOP of the manifold so I now had 0.010'' more meat at the bottom to crush the gasket properly.

- The gasket I'm using is (Fel-Pro 1205) and this time I used it with some RTV on both side of it around the port. Torqued the intake at 35 ft-lbs.

- Still had oil in the plenum. I then got rid of the PCV system and installed a breather.

- Still had oil in the plenum. Oil consumption was down to around a quart for every 600-700 miles. I then decided to change the intake valves seals.

- Still had oil in the plenum. I did remove the intake manifold again. I checked the torque on the bolts and it was down to around 23 ft-lbs. Sure enough 1/3 of the gasket (bottom part) was wet and the RTV didn't stick to the intake side of the gasket.
But the contact pattern impressions of the intake was good this time.

- I installed a new gasket with no RTV this time around the port. I went for a short ride of 30 miles. Came back removed the plenum and sure enough it was coated with oil (intake port as well). There is even oil in the TB.

- I even had an engine builder with more than 25 years of experiance installed my intake manifold with the same result.


So if your still reading this, is there some strange thing happening with that intake when it goes thrue some heat cycle. (expension, contraction).

Or does it have something to do with cam overlap at idle, low RPM. I don't see how oil would be going in the plenum at WOT.

Or the intake manifold gasket in this case FEL-PRO 1205 is not up to the task.

Or I just don't know how to install an intake properly ???? :cry:

Thanks

PAT

Put a thicker gasket on it (they make them) and torque bolt's to 30- 35 foot lbs.Retorque immediately as engine reaches temp and while it is running. Make sure your end seals are not holding the intake up from the heads.
I got wedge washers for the Holley SR as the angle of the face were the bolt head sits is different than the angle of the bolt on an LT-1 head.
I put 3/8" (about .060) flat washers under the 4 corners of the intake to check the gap at the top and bottom of the intake gasket surface,to see if they are the same at that height.

The only thicker gasket I found is Fel-Pro 1245 at 0.120''. It's a trim to fit gasket and I will most likely give it a try.
I'm not 100% convice that the gasket is the solution to my problem, I think there is something else going on inside that intake.

PAT

Heres my take on this as an HSR owner. I also have oil in my intake, I attribute it to the PCV system. One thing that you didn't mention was if you were cleaning the intake pieces after you removed them and inspected them. If it has oil in the intake when you take it off, and you put it back on and run the car, its not going to disappear.

If you read up on thirdgen.org you'll find that the HSR's were not sealing to the block right and leaking oil and vacuum leaks were the norm. What I would do in your situation is install that thicker gasket, crank the bolts down like was described before, and gob the crap out of the block mating surface with RTV. Obviously not TOO much but don't use it sparingly.

Also, are you sure you are burning it? It may be like mine and leaking out of the back of the motor from my oil pressure guage fitting.

It happens with minirams also. I think it has something to do with reversion at idle and plenum volume/pcv, but not sure. Me and all my buds with miniram intakes have the same problem.

Heres my take on this as an HSR owner. I also have oil in my intake, I attribute it to the PCV system. One thing that you didn't mention was if you were cleaning the intake pieces after you removed them and inspected them. If it has oil in the intake when you take it off, and you put it back on and run the car, its not going to disappear.

- I removed my PCV system and it didn't do much. At first I was sure it was the reason I had oil in my intake/plenum......but no.

- I do clean the intake and plenum with brake cleaner every time I removed them.

If you read up on thirdgen.org you'll find that the HSR's were not sealing to the block right and leaking oil and vacuum leaks were the norm. What I would do in your situation is install that thicker gasket, crank the bolts down like was described before, and gob the crap out of the block mating surface with RTV. Obviously not TOO much but don't use it sparingly.

-I never had any problem with the intake not sealing to the block so far. I'm using some Right Stuff and it works great.

-I bought the thicker gasket and will give it a try in the next couple days.

Also, are you sure you are burning it? It may be like mine and leaking out of the back of the motor from my oil pressure guage fitting.

-Never had any leaks around the intake. And when the car is idling blue smoke comes out of the tail pipes and the longer I will let it at idle (red light) the worst it will get. Also from looking at the spark plugs (at idle) you can see that the engine is burning oil.

It happens with minirams also. I think it has something to do with reversion at idle and plenum volume/pcv, but not sure. Me and all my buds with miniram intakes have the same problem.

-If it happens with minirams I wonder about the LT1/LT4 intakes.

-How many miles can you drive before you have to had a quart of oil ????

-If the new gasket doesn't change anything I'm going to install a carburator on the Victor Jr intake I have and see how it goes. I may end up selling a bunch of stuff.

PAT

Update

I installed the 0.120 thick Fel-Pro gasket part # 1245, put some RTV around the port on each side of the gaskets. Torqued the intake at 35 ft-lbs in 5 ft-lbs increments, I retorqued to 35 ft-lbs the next day.

I went for short ride of around 20 miles and when I came back I removed the plenum. There is oil again in the plenum. And yes It was cleaned when I installed it.

So now I think that something else is going on. :confused:

-I was told by somebody that it may have something to do with cam overlap and having one piston sucking oil from around the rings of an other one during a brief moment :confused:

I need someone with enough knowledge about this stuff to tell me what is happening inside my intake.

Because the oil can come from only 5 places that I know of.

-The intake gasket. (my contact pattern impressions is always good now) It's hard to believe now that it's the cause of my problem.

-From the intake valve seals. (they were change for an other brand with no luck)

-From the rocker stud hole. (when it's machined all the way in the intake port wich I don't have)

-From the PCV valve. (I don't have it anymore)

-From the cylinder when the valve is open ???

Please help me :cry:
I should be trying a carburator set up by the end of the week if everything goes well.

PAT

If it was cam related it would happen with the carb intake too.

If it was cam related it would happen with the carb intake too.

I agree with you but right now I realy don't know what else I should try.
And the carb intake is wet flow and the plenum volume is a lot smaller....will it change anything I don't know.

If it can be of any help my cam lobs profile are agressive (fast opening and fast closing.)

PAT

I agree with you but right now I realy don't know what else I should try.
And the carb intake is wet flow and the plenum volume is a lot smaller....will it change anything I don't know.

If it can be of any help my cam lobs profile are agressive (fast opening and fast closing.)

PAT

The differance would be that the gas going down the runner would keep it washed clean.
If the cam is over 250@50 and ya do a lot of low RPM driving then that would effect it but your cam can't be any more aggressive than mine.(mech roller in the high 260's with a .780 net lift)

The differance would be that the gas going down the runner would keep it washed clean.
If the cam is over 250@50 and ya do a lot of low RPM driving then that would effect it but your cam can't be any more aggressive than mine.(mech roller in the high 260's with a .780 net lift)

What I was told is that since the carb is wet flow the intake charge is heavier (gas and air mixed together is heavier than air alone) and it will be harder for anything to be sucked back in the plenum.

What bothers me is that I'm not alone with that problem and most people think that the PCV system is the reason they have oil in the intake. That's what I tought also until I removed it.

My cam is 234/240 @50 with .544 lift, it's not installed straight up it's 3 degrees more advanced if it can make any difference.

Anyway unless someone comes up with a good explaination about what is going on I will give the carb a try since I don't know what else I should do.

PAT

I've just removed my intake and I can tell you that the Fel-Pro gasket part # 1245 gave me the best result so far. The gasket wasn't wet anywhere around the intake ports.

But I'm still having oil in the intake/plenum so it's now down to 2 possible places.

-Intake valve seals. (that were changed with no improvement)

-From inside the cylinder when the valve is open.

PAT

I've just removed my intake and I can tell you that the Fel-Pro gasket part # 1245 gave me the best result so far. The gasket wasn't wet anywhere around the intake ports.

But I'm still having oil in the intake/plenum so it's now down to 2 possible places.

-Intake valve seals. (that were changed with no improvement)

-From inside the cylinder when the valve is open.

PAT


If the rings are seated there isn't supposed to be any oil in the cyl.

Hey you could try loking over at www.chevytalk.org look in the efi section there is a guy named Doug Flynn who works for Holley.He has always been very helpful.Hope this helps

If the rings are seated there isn't supposed to be any oil in the cyl.

There is always a slight amount of oil that pass the rings, it's not 100% efficient.

The engine has always done this and at first it was with total seal gapless top ring, I did took the engine apart last winter and had them change with speed pro rings after honing the cylinder of course.

Hey you could try loking over at www.chevytalk.org look in the efi section there is a guy named Doug Flynn who works for Holley.He has always been very helpful.Hope this helps

I will try to contact him when I have a chance thanks.

PAT

Update,

Went fot a ride with the carburator set up. And sure enough it didn't make much af a difference. There is still smoke coming out of the tail pipes.

I will be watching the oil level and see how it goes.

I really don't know what to do next beside doing a leak down test in the cylinders. I may try an other brand of valve seals just in case.

PAT

I have a suggestion for you. A buddy of mine, dreamer1q, had an engine built a while back, no matter what we did to that thing it would always burn oil. the effective octane rating of that motor was about 60 somthing with all the oil it consumed, and it still put down 303 to the wheels. Which bugged me because I have a good setup and only made 240 at the wheels. Anyway, turns out that the valve springs were catching the valve seals as they traversed from open to close and were letting oil pass by and into the cylinders. Also, it was discovered that the rings were probably stock and not made to fit a .030 over bore piston, like the ones he had. Therefore, leaving a hellacious amount of a gap. They never seated apparently.

2 things for you to try. Beyond that, you may want to have your heads sonic checked. My recommendation is look at your rings and valve seals.

Here is a link

http://www.michiganspeed.com/Speedforum/showthread.php?t=7744

the effective octane rating of that motor was about 60 somthing with all the oil it consumed, and it still put down 303 to the wheels.

I don't know how much I'm putting down but I'm trapping at 115.2-115.9 mph in the 1/4.
And from a video my brother made of me you can see smoke at idle (not a thick blue cloud more on the greyish side) and almost nothing at WOT and a good cloud during upshift.

Anyway, turns out that the valve springs were catching the valve seals as they traversed from open to close and were letting oil pass by and into the cylinders. Also, it was discovered that the rings were probably stock and not made to fit a .030 over bore piston, like the ones he had. Therefore, leaving a hellacious amount of a gap. They never seated apparently.

- The springs catching the valve seals is a good one...... I will take a look at that but I changed springs lately that have a bigger inside diameter than the last set and it still smoking.

- For the rings like I said before last year the engine had that problem with a set of total seal gapless top rings and now with speed pro hand fitted rings so :confused:

2 things for you to try. Beyond that, you may want to have your heads sonic checked. My recommendation is look at your rings and valve seals.

- I've had this problem since day one with brand new heads (AFR 190) close to 3500 miles on them now.

Hopefully the problem is from the valve seals since it's a lot easier to fix but I'm skeptical.

PAT

Grey smoke you say? Not Blue You say? Smoke during upshifts you say? I think we have a winner. ;)

That motor in dreamer's car ran a best of 12.98 @ 106 mph, blowing smoke at the starting line and on upshifts too, never really had a blue color to it. :)

I am also very impressed with your times, 115mph with a 383 HSR and AFR 190's while burning oil? I just ran a new best with my 355 HSR with AFR 195's last night. 13.5 @ 100. :lol:

EDIT: FYI, I also had an "oil" coating inside my HSR when I had no PCV installed. Strange huh.

Just another thought----- Is it possible your oil drain back in the heads is restricted?
I cut the head gasket for the drain back and have ground the block so the drain back is clear.

That would submerge your seals in oil while running and they aren't a positive seal.

stop over at www.stealthram.com and see what they have to say about it.

Here's another thought,Could it have something to do with the way the distributor fits in the block.My thought is maybe oil is climing up the shaft and over loading the valley area.I know not a good thought but one never knows.

BTW oil in the intake has ALWAYS been an LT1 issue ;)

Grey smoke you say? Not Blue You say? Smoke during upshifts you say? I think we have a winner.

:thumb: Did I win a FREE rebuild on my engine...... :D So basicaly you are telling me my rings are dead :death:

I am also very impressed with your times, 115mph with a 383 HSR and AFR 190's while burning oil? I just ran a new best with my 355 HSR with AFR 195's last night. 13.5 @ 100.

I'm impressed with my MPH but not my times, the best I've managed so far is 13.01. I have to say I'm using el cheapos street tires so my 60' time on average is around 2.3, and I have to be really gentle leaving the starting line so I don't spin like crazy (cam wakes up at 3000-3200 rpm).

EDIT: FYI, I also had an "oil" coating inside my HSR when I had no PCV installed. Strange huh.

I'm sure someone knows exactly why some EFI intakes gets coated with oil.
I did contact Doug Flynn who works for Holley via email and he did asked for a copy of that post but I didn't hear from him after that.

Just another thought----- Is it possible your oil drain back in the heads is restricted?
I cut the head gasket for the drain back and have ground the block so the drain back is clear.
That would submerge your seals in oil while running and they aren't a positive seal.

:think: This is something I will have to take a look at.....if that is my problem I quess my high pressure high volume oil pump is not helping me at all.

stop over at www.stealthram.com and see what they have to say about it.

I did use the search option but didn't find much.

Here's another thought,Could it have something to do with the way the distributor fits in the block.My thought is maybe oil is climing up the shaft and over loading the valley area.I know not a good thought but one never knows.

All I know is that my block got some restrictors (plugs) installed in the lifter valley so less oil goes on the cam/cranks (rubs power).

BTW oil in the intake has ALWAYS been an LT1 issue

Even with the PCV removed ??? My stock TPI set up had some black stuff inside the plenum (sure after 60 000 miles) but it sure was never wet.

So now what may be the cause of this is....

- Valve springs touching the seals.
- My oil drain back in the heads is restricted thus submerging the seals in oil .
- My rings are dead.

What are the signs of an engine with glazed cylinders (not sure if I'm using the right word) or bad honing ????

PAT

P.S. I may go to the track on sunday and see how the 750 cfm demon carb and the Victor Jr single plane intake manifold do compare to my HSR set up.

This is something I will have to take a look at.....if that is my problem I quess my high pressure high volume oil pump is not helping me at all.
----------------------------------------------------------
Your pump is not hurting ya. When ya use Fel Pro head gaskets they will block part of the hole. I have had blocks that are made such that they block part of the hole too.The hole has to be wide open with nothing interfering with the original hole size in the head.
If ya notice the LT-1 head has the drain back holes damn near parallel with the ground with hardly no angle to help drain back.
Simple to correct when ya mock it up but the metal shavings from the grinder have to be kept out of an assembled short block.(you knew that)

Checking in, this post has a lot of good information in it and I'm experiencing a very similar issue on my 93 LT1.

Update,

I removed the driver side valve cover to take a look at the valve seals and the oil drain back holes in the heads.

First in both holes I can't see the gasket (good) but the hole in front of the engine I can see that part of the block is in the way. It's in the 6 to 9 o'clock position and it's blocking maximum 1/6 of the head hole.

The hole at the rear is fine.

One thing I've noticed is once your in the block the holes path kind of goes upwards ???

I'm no expert but I find those holes in the heads to be kind of high, there needs to be a good level of oil before it's drained back in the block ???

Now for the valve seals, while I was looking at #1 intake valve what did I found. I found the seal hiding under the retainer :mad: . I don't think it can seal pretty good from there :rolleyes:. So the spring is probably touching the seal.

Before anyones think I found the source of my problem you have to know that the engine have done this with 3 different set of springs and none had the samre ID (an other story in itself). 3 different set of valve seals and 2 set of rings. So what I will do when I have some time this week I will change the valve seal again and make sure I use a brand that fits with the springs.

One last thing, is it normal that when I lift the valve covers that the oil level that sits in the heads is lower than the oil drain back holes :confused: Where is the oil going ?

PAT

What are the signs of an engine with glazed cylinders (not sure if I'm using the right word) or bad honing ????

PAT

P.S. I may go to the track on sunday and see how the 750 cfm demon carb and the Victor Jr single plane intake manifold do compare to my HSR set up. Sounds like the problem is the valve seals and springs not playing well with each other, but here is the shadetree method to check ring seal:
Do a compression test.
Do a compression test again, but this time squirt a little gear oil in each cylinder before you check it.
If you get a substantial increase in cranking pressure with the gear oil, you have ring seal problems.

Let us know how you made out at the track. :)

Sounds like the problem is the valve seals and springs not playing well with each other, but here is the shadetree method to check ring seal:
Do a compression test.
Do a compression test again, but this time squirt a little gear oil in each cylinder before you check it.
If you get a substantial increase in cranking pressure with the gear oil, you have ring seal problems.

Let us know how you made out at the track. :)


30W motor oil will do just as good.

Let us know how you made out at the track.

I didn't go on sunday since I found out about the valve seal. I don't think it would have been bad anyway, can't be worst. Maybe next sunday.

Priority this week will be a compression test.

PAT

Update,

I just did a compression test, not on all cylinders because of headers clearance with the tester.

Here is what I have so far,

1-165 2-170 3- 4-175 5- 6-170 7-170 8-175

And the one I've tested with oil squirted in the cylinders,

1-200 2-195 3- 4-195

Now the question is can this be called a substantial increase in cranking pressure ? or is it what I should expect when doing this test.

PAT

Update,

I just did a compression test, not on all cylinders because of headers clearance with the tester.

Here is what I have so far,

1-165 2-170 3- 4-175 5- 6-170 7-170 8-175

And the one I've tested with oil squirted in the cylinders,

1-200 2-195 3- 4-195

Now the question is can this be called a substantial increase in cranking pressure ? or is it what I should expect when doing this test.

PAT


That's about right,at least shows ya it isn't the rings.

That's about right,at least shows ya it isn't the rings.

So at least I won't have to take the short block apart again :rolleyes:

It has to be from the intake valve area then :confused:

PAT

So at least I won't have to take the short block apart again :rolleyes:

It has to be from the intake valve area then :confused:

PAT

I still think it has something to do with oil return and valve seals.PC seals cause to much wear to use and I don't know of any other to suggest.

I still think it has something to do with oil return and valve seals.PC seals cause to much wear to use and I don't know of any other to suggest.

The engine builders that helped me built this engine is convince that the oil return is not the cause of this but at the same time he can't pin point for sure what is the cause.

Like I said above there isn't really any restriction there.

PC seals, who makes them and what kind of material are they made of.

PAT

The engine builders that helped me built this engine is convince that the oil return is not the cause of this but at the same time he can't pin point for sure what is the cause.

Like I said above there isn't really any restriction there.

PC seals, who makes them and what kind of material are they made of.

PAT


Like I said in an earlier post,the holes are damn near flat with the ground,there is no incline to help it drain so ANYTHING that is blocking the original size of the hole hurts the flow and look at making the hole larger(original size all the way through),with more incline.
Perfect Circle makes PC seals. They will wear your guides out from lack of oil.
The oil has to get to a certain level to start returning to the pan,if that level is at or above the seals the intakes will be slobbering in oil. I generally run a neoprene seal on the intake and nothing on the exhaust for trailer queens and two neoprene on street engines. The PC seals will stop the oil IF it's the seals and the oil level is not above the seals.

Like I said in an earlier post,the holes are damn near flat with the ground,there is no incline to help it drain so ANYTHING that is blocking the original size of the hole hurts the flow and look at making the hole larger(original size all the way through),with more incline.

Now you got me thinking about something. I'm wondering if my AFR rev-kit bar can be hurting the oil flow. If I'm not mistaken it's sits near the path where the oil goes back in the block.

I will have to take a look at that when I'll switch back to my HSR intake.

PAT

Now you got me thinking about something. I'm wondering if my AFR rev-kit bar can be hurting the oil flow. If I'm not mistaken it's sits near the path where the oil goes back in the block.

I will have to take a look at that when I'll switch back to my HSR intake.

PAT

Ok,let us know.

1racerdude,

I'm trying to find a part # for some PC seals but I can't find any. Looks like perfect Circle is part of Dana and they do have valve seals but they don't call them Perfect circle :confused:

http://www.dana.com/Automotive_Systems/Products/Sealing%20Products/Valve%20Stem%20Seals/valve_stem_seals.aspx

I know we've talked about that before but I'm still wondering how much of an impact my Moroso oil pump part # 22112 (high volume) has. Let say I have no restriction with the oil return can the pump push more oil than what can be return in the block from the heads (to a certain degree)???

PAT

1racerdude,

I'm trying to find a part # for some PC seals but I can't find any. Looks like perfect Circle is part of Dana and they do have valve seals but they don't call them Perfect circle :confused:

http://www.dana.com/Automotive_Systems/Products/Sealing%20Products/Valve%20Stem%20Seals/valve_stem_seals.aspx

I know we've talked about that before but I'm still wondering how much of an impact my Moroso oil pump part # 22112 (high volume) has. Let say I have no restriction with the oil return can the pump push more oil than what can be return in the block from the heads (to a certain degree)???

PAT


The ring and band type are them.
It may but,but ya would have to have a restriction somewere.
If ya had a big pan,the HV pump would not run out of oil so it would be returning it and it wouldn't be in the intake.Has your system run out of oil at any time?
Think ya are looking in the wrong place for the fix.

The ring and band type are them.

They kind a look like the Fel-Pro SS 72527 I have right now.

It may but,but ya would have to have a restriction somewere.

I've talked to my engine builder again about that and he is positive that there is no restriction there QUOTE I've been building engine for 25 years and never had that kind of problem before ......UNQUOTE
The only thing that he wasn't to sure about is my REV kit that may be in the way somehow.

He thinks that changing my pump to a Melling MEM-55 may do the trick.

I'm on a trial and error quest :(

If ya had a big pan,the HV pump would not run out of oil so it would be returning it and it wouldn't be in the intake. Has your system run out of oil at any time?

Never saw the oil pressure needle dropped....but when I'm racing I don't have my eyes on that gauge that much. My pan is a Moroso 6 quarts.

Think ya are looking in the wrong place for the fix.

I don't feel like lifting the heads just to grind the block....I want to make sure that I've tried everything else before.

PAT

Update,

First I removed my valve covers to see how high the oil level would go since it's smoking at idle. The oil level is fine, the seals that gets the most amount of oil (#7 cylinders of course ) and gets oil to about half of it's total height.

I then replaced all the valve seals with Victor Reinz seals on the intake (they really looks like the Fel-Pro I had) and crane cams teflon seals on the exhaust valves.

One thing I noticed is that there was oil under each seal I removed (worst with the exhaust ones) I don't think I should see oil there, should I ????

So I think that 1racerdude theory about having the seals slobbering in oil is good. The oil gets probably above the seals at higher RPM but not from a restriction in the block.
What I think is that the drain back holes in the heads were machined to high because with the valve cover removed and the engine off (looking at #7 cylinder, lowest point in the head) with the oil level being at the lowest point of the drain back hole there is already oil to half the height of the valve seal.

It would be easy to have oil above the seals if the oil level gets higher than that.

Does it make any sense, and how high is the lowest point of the drain back hole compare to the valve seals in a production SBC ??? I have AFR 190 heads and don't have anything else for comparison.

I even put some teflon tape on the rocker stud just in case, and after a 20 miles drive it was still smoking like usual. :cry:

PAT

That's what I was talking about the height and angle. Ya might look into grinding them lower and more angle. Don't know the thickness without sonic checking and there may not be enough material there to do it.Call AFR and talk to someone knowledgeable about the problem.Bet the answer is "we never heard of that problem".
The exhaust seal is no problem,it is blowing oil out,either the exhaust or back up the guide.Might account for the exhaust smoke.
There will be a very small amount of oil that goes by the seal to lube the guide.

How much guide clearence is there?

How much guide clearence is there?

I don't know beside the fact that they are like new, you can only feel a slight movement of the valve stem in them.

Bet the answer is "we never heard of that problem".

That's funny I talked to my brother yesterday, that's exactly what I told him I was probably gonna get from AFR. Anyway that's what they told me when I called them about my valve float problem with their springs.

PAT

The oil problem with the AFR 190 head is common. They didn't design the drainback holes properly.

http://forums.corvetteforum.com/showthread.php?t=1061647&highlight=afr&forum_id=7

The oil problem with the AFR 190 head is common. They didn't design the drainback holes properly.

http://forums.corvetteforum.com/showthread.php?t=1061647&highlight=afr&forum_id=7


Did ya get that from AFR or through experience? That is what I have been saying that the angle and location are such that the oil stays at a high level in the head and drowns the seals.

Thanks onefastgta for the link.

I will be contacting that guy at AFR next week and will probably send him those heads. :mad:

I went to see a friend of mine that has lots of SBC heads, and sure enough looking at 3 different brand of heads all of there drain back holes are machined at the lowest point in the heads and it's well below the valve seals. That is not the case with my AFR 190.

Thanks 1racerdude for your help. :bow:

PAT

Thanks onefastgta for the link.

I will be contacting that guy at AFR next week and will probably send him those heads. :mad:

I went to see a friend of mine that has lots of SBC heads, and sure enough looking at 3 different brand of heads all of there drain back holes are machined at the lowest point in the heads and it's well below the valve seals. That is not the case with my AFR 190.

Thanks 1racerdude for your help. :bow:

PAT



Anytime

I have the AFR 190's also. They are an old casting, from back in 1994 so it's probably their first design. I can't even run the motor long enough to adjust the valves with the valve covers off without oil spilling over the rail of the head onto the headers. I've also had problems trying to keep these valve covers from leaking, it's been a challange to say the least. :(

I have the AFR 190's also. They are an old casting, from back in 1994 so it's probably their first design. I can't even run the motor long enough to adjust the valves with the valve covers off without oil spilling over the rail of the head onto the headers. I've also had problems trying to keep these valve covers from leaking, it's been a challange to say the least.

I got mine brand new 3 years ago and they are not better than yours.

PAT