Kingtal0n

doesn't the fact #8 fogged the WD40, blasted it out of the engine give some clue? If it came AWAY from the valve, then the valve is leaking? So pull the valve out. Swap it with another valve and repeat test? Something like that? Once the valve seals you can test the ring.

You made it sounds like the intake valve is leaking into the intake manifold

TedH

It was so bad that the WD40 that had leaked past the valve was pushed BACK around the intake valve by the compressed air and out of the intake port (I had removed the intake for the test).

Now the heads are fixed and I am performing a final leak-down on the new short block. Rings were leaking for sure with the lack of good oil control. Guides checked out ok.

ezobens

Bent valves is a little scary.
I’m not a gambling man so if had any bent valves, I would have replaced them on principle.
Not sure how you can successfully straighten bent valves?

lars

Hey Ted -
I got your wussy-*** 40% leakdown beat by a longshot... just had a guy drop off a Vette from Mississippi, and I did a leakdown to see if it had other problems than a flattened cam lobe... I just tested one cylinder at 72% leakage, and it's all going by the rings... That makes your little 40% valve leak seem like a performance engine...!

Hey George -
72% leakage past the piston & rings just provides some good crankcase ventilation, right..?

Lars

TedH

And I thought my rings were bad Lars!!!

I installed the heads and performed a leak-down test on the new short block and discovered four (4) chambers with 30-40% leakage out of both the intake and exhaust valves. I talked with the cylinder head builder and he suggests that his attempts to resolve the excess run-out on the valves either didn't work or made matters worse. He returns to the shop early next week and is committed to fabricating a plate to test SBC heads as first order along with working on my heads.

At this time, I am holding on spending more $$$ on these heads. He says he has a nearly complete set of SBC valves to install FREE.

I suspect poor quality valves have been the issue in these heads since day 1. Will see what we find next week.

Gotta pull the heads this weekend and clean out the threads in the short block.

If I pull the trigger on a new set of valves (I & E), are stainless the recommended type for street performance? What brand won't break the bank but give good quality? Manley Street Master Street Flo valves (in sets of 8 of each) appear to be competitively priced at Jeg's and Summit.

lars

Ted -
You can get some very nice valves at fair prices, and actually get a performance increase from the flow. I would buy a set of stainless, necked, tuliped, swirl polished valves, such as ones offered by SI, Manley, or similar - there are several good suppliers for these parts.

derekderek

Probably burnt not bent. Either way, 5 cents a pound scrap metal. You would NEVER straighten a bent valve unless it was irreplacable low performance collector item type engine. 32 Hupmobile or something.

TedH

I am liking the Manley Street Master Street FLO for the potential performance gains. Jeg's has sets of 8 at $88 (on sale).

Once my cylinder head builder weighs in on the specs (ie. if stock specs apply), I may pull trigger Tuesday.

TedH

Builder thought he resolved the run-out but I suspect inferior metal in the valves. Lost faith in the valves in the heads. They came from Indy Cylinder Head in the DART Iron Eagle castings so I thought good quality.

Brut

Lars.......only you could make a 72% leakage seam like a badge of honor !!!

Kingtal0n

Time for an LS Engine? An aluminum 5.7L electronic fuel infection.. infestation...