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Problems after break-in
Shelby alum block, 428 crank, Edelbrock heads, Shelby roller tip rockers.
After 500 mi break-in, This engine has developed some problems which may or may not be related: 1. Left bank plugs wet with oil, oil smoke out the left side pipe. (running no restrictors to rockers), rt side ok. 2. rear main seal leaking . 3. Running webers, only vent is rear of intake manifold, none on valve covers. I.m thinking I'm getting too much oil up in the heads. Thoughts ? |
Intake gasket.....
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Brent:
At all 4 cyls? I used the super thick ones from Survival mtrspt,as the std ones were too skimpy after cutting to match ports. I'll look at it closely. Have you ever built one using the Shelby rockers and stands ( roller tips, bushings in arms) If so, did you use oil restrictors to the rockers? I asked various people before the build about this, and could not get a definate answer. |
Well, logically, you're going to get the same amount of oil to both sides, so if one side gets flooded, they both should get flooded.
If you have an intake manifold that was not machined correctly (happens often), then even the best intake gaskets will not help you. Remember, the FE is special in the sense that the intake ports have oil all around them. If there is a slight gap or the gaskets are not doing their job, they can suck oil. I've used about every rocker combination possible and I always restrict oil to the top end, either by something in the block's deck, or more commonly, something in the feed hole to restrict it. |
Brent: re; oil the same to both sides, yeah, thats what I figured also, but pertaining to how much oil is getting up there can the engine be run at idle with v/c off, or is that a big mess? I was thinking of putting a stand pipe in the valve cover to measure whats up there. There have been a couple of times I have seen my oil pressure (mechanical) bounce around and hit zero for a split second, like the pump is sucking air !! Aviad 13 qt RR pan with wind tray! But restrictors should help, it looks to me like I could put them under the rocker stand as opposed to between the deck and head. Yes? I think .060 is min size ?
PS: I rebuilt some chebbies, 351Ws, and a ton of acft engines, but this is my first FE !! Runs like a rocket booster, in spite of the problems. Also do you think it needs more than the intake breather ? Thanks for your input, Tedps |
You won't be able to run with the valve covers off. I can't even prime the pump with the valve covers off without making a mess.
I tap the hole in the head to a 12-24 and use a set screw with a hole in it. Since you can't tap with the heads on, find a piece of tubing and shove it down in the hole. I generally use .070". Also, keep in mind that oil pans and pickup clearances are usually spot on without the windage tray. Most of my Moroso and Aviaid stuff comes in at 3/8" clearance WITHOUT the windage tray. By the time you add the tray and another gasket, the clearance is going to be up there, and it's very possible that you are uncovering the pickup. |
Yes, you need a PCV valve and a breather.
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I guess you don't have an oil tube at the front of the intake with a breather cap? If not - how do you put oil in it with only the rear breather and no access on the valve covers? Or is there a gasketed oil fill cap (non-breather) on the valve cover?
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Dan; breather at rear of int has K&N breather which I just pull off to add oil.
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Brent:
IR intake (H&M weber intake, old ) has no vac ports as IR don't produce enough vac to be useful. HOWEVER, anticipating going to Eightstack efi in the future, I did this................. |
I have two vac ports at the rear small fitting for vac sig for efi computer, lg 3/8 for pwr brakes or ? This may work for pcv?
Also, too late, I found a thread spelling out the shortcommings of the early shelby blocks, one of which was oil drain holes at rear main being too small, / being covered by pan flange and gaskets as one cause of rear main seal leaks My block is sn 56, so very early. |
I think the standard without PVC is at least two breather locations to have some degree of in/out cross ventilation. With a rear breather, my barely worth 2 cents worth is that you probably need a PVC line pulling off of a valve cover for best ventilation. If your vacuum port is also at the rear of the intake it will short circuit with the rear-mounted breather. May still work - just not as effectively (at least in my humble, barely-informed opinion).
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The rear breather will have enough area - but it can sometimes get a fair amount of oil mist back there - make sure you're using a basket with the wire mesh. I normally use a breather in front of the intake or on a valve cover when possible - but sometimes cosmetics out weigh practicality.
We make some little drop in restrictors for Edelbrock heads that simply push into the oil feed holes - they have a .060 hole and seem to be plenty adequate. the intake gaskets are very good material, but you also need to have square and flat flanges for them to seal - I still tend to use a really thin smear of silicone around the ports just because... |
Update:
Barry: I used the Blue thunder thick gaskets (which I can't find on their website). Removed carbs to check intake runners. All look good with no signs of leakage, but I notice they want to separate (they are two gaskets glued together). Where the intake joins the head, all gasket edges look good with just the smallest bead of gray sealer showing on both sides. I also noticed the right side plugs are slightly wet (oil). I installed a PCV in the right V/C, but havent run the engine yet,still have other things to ck. Thinking valve seals. |
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Here's a pic of the int gasket:
You can see how they are separating due to the exposure to the hot oil. Now I'm thinking valve seals, which were installed by the shop that did the head work. They convinced me to have them install a type that supposedly were better for hi perf engines, as opposed to what I had provided to them, but I don't remember what type they were. I'm going to remove rocker assy's to ck the roller tips (they were not turning, and were beat flat when I got the car, had them rebuilt ) so that would be a good time to change seals. |
Gaskets will be fine where they are under clamp load - BT has them laminated to double up the thickness.
Make certain the PCV is adequately baffled - recently had one where we could clearly see the oil stream entering the intake runner from the vacuum port. Oil being sucked through the valve. We use the blue Viton valve seals on nearly everything. |
Barry: Yeah, I think it was viton seals they used.
Re; PCV, there are no baffles in my tin vc's, I'll try it anyway, I can always plug it if the engine turns into a mosquito fogger !!!! |
With your oil pressure going to zero I would assume that you are pumping the oil pan dry for a second and need restrictors. Getting a lot of oil in the top of the head and getting over the seals some and causing the smoking. It may be the intake gasket some but when an intake gasket leaks it usually gets into all of the cylinders but with yours having individual runners it very well could be the intake gasket on that one side. Check the match and angle before you bolt it down again and make sure the intake bolt holes are opened up enough where the intake does not bind in any way on the bolts as you tighten iy down. Just some ideals to check.
Good luck, Keith |
So it turns out it was the drivers side intake gasket that squeezed out the bottom of # 6 & 7 cyls. I removed the manifold and checked manifold to block and heads alignment and didn't find any glaring discrepancies. I'll see if my machine shop can check/mill intake if nec.
I think the double thickness BT gaskets were too thick, so i need to find some other gaskets. I'll start a new thread for that. |
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