Pistons hitting valves HELP!!
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Junior User
Joined: Nov 2011
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1. The head is from a separate previously rebuilt engine that was bored out .040. The head was rebuilt and put on the original block and worked great. Since then I have scrapped that block as the block itself had issues. I had a separate block decked (.003 taken off surface) and bored out for .020 pistons.
2. I have used both original cam and new cam and both come out with same outcome. Since the previous block had been worked on far more than this...I highly doubt I could have a clearance issue since that head has not been touched since it was on the other block and worked fine. (The second head has been resurfaced...again, but I will diagnose that one after I get the good head figured out)
3. The new cam does have a good deal more lift than stock cam, but neither are working now.
4. Through all my researching there is NO thicker head gasket for this engine. Felpro are the thickest ones supposedly. If you know different by all means correct me.
5. Been checking lifters, but wouldn't be better to check with them up (representing oil pressure as it will have when running?)
2. I have used both original cam and new cam and both come out with same outcome. Since the previous block had been worked on far more than this...I highly doubt I could have a clearance issue since that head has not been touched since it was on the other block and worked fine. (The second head has been resurfaced...again, but I will diagnose that one after I get the good head figured out)
3. The new cam does have a good deal more lift than stock cam, but neither are working now.
4. Through all my researching there is NO thicker head gasket for this engine. Felpro are the thickest ones supposedly. If you know different by all means correct me.
5. Been checking lifters, but wouldn't be better to check with them up (representing oil pressure as it will have when running?)
Senior User
Joined: Feb 2012
Posts: 445
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From: western Oregon
Taking a deck Hight measurement as per specs requires some special tools. The block possibly had been cut before you got it.... If the stock cam binds also then it is out of time or to tight. Put a degree wheel on the engine ( mounted on the crank) and slowly turn the engine and check the cam timing if it is out of time you will see it best this way.
Postmaster
Joined: Dec 2004
Posts: 2,941
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From: Maple Valley, WA
Its obviously not the inherent cam timing if the stock cam does it as well... Im going to assume you have the timing marks lined up correctly, so that pretty much leaves either deck issues or valvetrain issues. If its a deck issue, that block would have to be cut a huge amount... Which is very doubtful... Blocks are usually only cut .005 to .010" at a time... If the heads were shaved a lot, that might put the valves closer to the piston, but that depends on the valve job... As Russ said above, it could be an issue with new valves if those were installed, the new valves really should be ground to set correctly in the pocket... If they were just tossed in *****-nilly, than that could be the issue there as well.
Lots of stuff to check, Id take the heads back off and inspect them, as well as piston height above the block deck... I know its a PITA, but its the only way to get a solid answer.
The only cams Delta has that have "more lift" are NMB2's grind, My grind, and Typefour's grind, and I dont think Russ's grind has all that much more lift than stock... If you pull the cam out, can you tell us what grind number it is please? Its on the back of the cam.
Lots of stuff to check, Id take the heads back off and inspect them, as well as piston height above the block deck... I know its a PITA, but its the only way to get a solid answer.
The only cams Delta has that have "more lift" are NMB2's grind, My grind, and Typefour's grind, and I dont think Russ's grind has all that much more lift than stock... If you pull the cam out, can you tell us what grind number it is please? Its on the back of the cam.
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1. My machinist recorded that he removed .003 that's how I know. I highly doubt this block was ever re-done all wear in it looked right for the miles.
2. The rocker arms are new, but were already used on these heads prior to this build.
3. The engine turns over fine with no lifters or pushrods installed, but when the rocker arms are tightened that is when it hits, I am of course assuming it is hitting the valves.
4. I will get the number for the cam when I get it out. I do know it was the torque grind cam.
2. The rocker arms are new, but were already used on these heads prior to this build.
3. The engine turns over fine with no lifters or pushrods installed, but when the rocker arms are tightened that is when it hits, I am of course assuming it is hitting the valves.
4. I will get the number for the cam when I get it out. I do know it was the torque grind cam.
Laughing Gas
Joined: Aug 2003
Posts: 919
Likes: 4
From: Newberg Oregon
you need to "drain" the lifters, slowly torque them down to bleed out the trapped oil. This should be the fix. They do not run topped out in the engine, BUT if your oil relief sticks shut after water washing the filter header during repair it will create enough oil pressure to pump them up. Usually the oil filter will blow off first.
Posting Guru
Joined: Dec 2012
Posts: 1,065
Likes: 2
From: western washington
Take the rockers off and turn her over...if she rolls fine put rockers on intake..ect then exhaust ect 
,,,, then you know witch valve is touching...
,,,, then you know witch valve is touching...
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Postmaster
Joined: Feb 2011
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its my understanding that the lifters will pump up to the point that there is no slack in the pushrods, and no further, thus removing all need for valve adjustments. so with your lifters totally collapsed, no contact, with your lifters pumped up as far as they can go, and valves not closing because of it, it may hit. but with the lifters pumped up to the right level, thats the point you have to study
Senior User
Joined: Feb 2012
Posts: 445
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From: western Oregon
Got a dial indicator?...Set it up and put the tip on the top of the exhaust valve spring next to the retainer and check the valve movement. If it is moving the correct amount for the cam specs. Then start shimming the valve tip with feeler gages until you run out of clearance. then you will know the aprox valve clearance to the piston. It might take a few shims to get full movement with a flat lifter, then shim to touch its a little bit of work but if you take good notes it might be the info your looking for.
Postmaster
Joined: Feb 2011
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well boys, i got my heads on today, slapped the rockers on there, and now have valve to piston contact. similar story to the OP, i had both the block and heads milled down, and here we are.
i'm thinking about taking some thin washers and raising the rockers up a little bit, maybe .030 or so. does that sound like a reasonable plan to you guys?
i'm thinking about taking some thin washers and raising the rockers up a little bit, maybe .030 or so. does that sound like a reasonable plan to you guys?