Thicker head gaskets?

[Mrbill426]

Ok... so I have the 340 long block put together after degreeing the cam, checking piston to valve clearance on #1 (plenty) without a hd gasket, and now  with the heads torqued down with gasket the engine won't rotate.    Long story-short  I pull the heads off and it turns with a ratchet so my guess is even though I checked the clearances on #1,  I have pistons hitting the heads, or the gasket is wrong?  When I checked with clay I put it in the valve pockets and not on top of the pistons.
The pistons are above the deck slightly but the J heads have open chambers and with the gasket on I would think there would be room... I am stumped 

Do I need thicker gaskets?  I am using Fel-Pro #8553PT and when I measure them after removing them they are crushed to about .054" .
It is bored +.020" if it matters but the gasket opening is bigger than the bore.

Thanks

[Chryco Psycho]

the 340 does come above the block & if the block was planed the piston could hit the heads , Cometic makes different thickness head gaskets , you may have to test with the clay again & confirm the piston is stopping against the heads .

[gzig5]

With stock style pistons, even though they are ~.020 above deck, I would think that an uncut open chamber J-head would not interfere with the piston.  They run those 12.5:1 domed pistons on X and J heads with no special clearancing  I'm aware of, and they fill the chamber.  You should be able to run a standard steel or thin .030" gasket.  The one you have is considered thick.  I would look elsewhere. 

Maybe try turning it over intermittently as you torque the head?  Is it always with one cylinder at TDC while torquing or when it gets to TDC?

[Mrbill426]

@Chryco Psycho thanks, I am going to check it with the clay as I don't have depth gauges; I'm going the lay strips of it across the crowns and check on piston on each bank at a time.  The block was not surfaced but during the valve job the heads were recorded as being cut down by .008" which does not seem like much to me ... at least this time around.  I have no reason to believe the block had ever been out of the car before this. 

I also tried it with one head at a time to see if maybe one bank was off but got the same results with either.  I did this with the head bolts finger tight.

What gets me is I had thought the pistons I installed were basically the same spec as the earlier higher compression 340 and that they would fit fine even with a resurface; only worry would be piston to valve with a higher than stock lift cam    They are Speed Pro #L2316F-20 pistons.  I CCd the heads and all the chambers came in at about 70 cc.  Were the earlier 340s (that) tight up top?  How much clearance should there be?


When I say it would not rotate I mean it does but with force as though a bind exists so I stopped and investigated.  I wonder If I need to pull the pan back off to see if there is any damage the the rod bearings that only have assembly lube... crushed bearings?

Thanks

the 340 does come above the block & if the block was planed the piston could hit the heads , Cometic makes different thickness head gaskets , you may have to test with the clay again & confirm the piston is stopping against the heads .

[Mrbill426]

@gzig5 I am not sure.  Once I verified I had plenty of valve space on #1, I assembled the the short block only leaving the rocker shafts loose so the arms (and dry lifters) were not under load, so valves are always closed.  I did not rotate it again until last night when I went to torque the balancer bolt; that is when I discovered the bind up.  Pull the heads and it is free to turn.

Wait... valves closed... you think THAT is the "bind"...static compression???    Could it be that simple???

With stock style pistons, even though they are ~.020 above deck, I would think that an uncut open chamber J-head would not interfere with the piston.  They run those 12.5:1 domed pistons on X and J heads with no special clearancing  I'm aware of, and they fill the chamber.  You should be able to run a standard steel or thin .030" gasket.  The one you have is considered thick.  I would look elsewhere. 

Maybe try turning it over intermittently as you torque the head?  Is it always with one cylinder at TDC while torquing or when it gets to TDC?

[gzig5]

@gzig5 I am not sure.  Once I verified I had plenty of valve space on #1, I assembled the the short block only leaving the rocker shafts loose so the arms (and dry lifters) were not under load, so valves are always closed.  I did not rotate it again until last night when I went to torque the balancer bolt; that is when I discovered the bind up.  Pull the heads and it is free to turn.

Wait... valves closed... you think THAT is the "bind"...static compression???    Could it be that simple???

With stock style pistons, even though they are ~.020 above deck, I would think that an uncut open chamber J-head would not interfere with the piston.  They run those 12.5:1 domed pistons on X and J heads with no special clearancing  I'm aware of, and they fill the chamber.  You should be able to run a standard steel or thin .030" gasket.  The one you have is considered thick.  I would look elsewhere. 

Maybe try turning it over intermittently as you torque the head?  Is it always with one cylinder at TDC while torquing or when it gets to TDC?

If the plugs are in it, that will cause resistance at the top of the stroke.  With the plugs pulled it should turn over the same as without the heads on it, other than the extra effort to open the valves.

[Mrbill426]

Well I checked it with clay (see photos) and using calipers the clearance in the tight area is around .150" with the  .054" thick gasket so that seems all good. 

Yes the plugs are all in (for painting) so I guess it was locked up with compressed air all along, and I suppose some vacuum as well with pistons trying to "intake" air through closed valves.  None of those factors dawned on me until now that I wasted time and a pair of head gaskets.  Now I wonder about the head bolts... how many torquing cycles can they take? 
Once when new; again when I put it back together, and will be a third time after I get new gaskets.  I have used oil on the threads and under the bolt heads.

@gzig5 I am not sure.  Once I verified I had plenty of valve space on #1, I assembled the the short block only leaving the rocker shafts loose so the arms (and dry lifters) were not under load, so valves are always closed.  I did not rotate it again until last night when I went to torque the balancer bolt; that is when I discovered the bind up.  Pull the heads and it is free to turn.

Wait... valves closed... you think THAT is the "bind"...static compression???    Could it be that simple???

With stock style pistons, even though they are ~.020 above deck, I would think that an uncut open chamber J-head would not interfere with the piston.  They run those 12.5:1 domed pistons on X and J heads with no special clearancing  I'm aware of, and they fill the chamber.  You should be able to run a standard steel or thin .030" gasket.  The one you have is considered thick.  I would look elsewhere. 

Maybe try turning it over intermittently as you torque the head?  Is it always with one cylinder at TDC while torquing or when it gets to TDC?

If the plugs are in it, that will cause resistance at the top of the stroke.  With the plugs pulled it should turn over the same as without the heads on it, other than the extra effort to open the valves.

[Chryco Psycho]

I would rotate it with the heads on & the rockers off so the valves stay closed if it turns the problem has to do with the valves .

[gzig5]

For a stock-ish build, I would re-use the head bolts with that few of cycles on them.  I didn't think that head gaskets were one time use unless they tore on removal or were run for a while.  If you got to have the peace of mind, stock head bolts and that felpro gasket aren't terribly expensive.  Glad you figured it out. 

[Mrbill426]

@Chryco Psycho unless I am misunderstanding you right now, when I discovered this "problem" the heads were on but the rocker shaft bolts were backed off so the all the valves were closed, and spark plugs installed for painting.  *Remember my earlier concern about the push rods being at such a steep angle to the (dry) lifters and you suggested leaving them loose for now?

Reference this thread: https://forum.e-bodies.org/engine-transmission-and-rear-end/4/valve-train-question/22154/msg268947#msg268947

Am I on track?

I would rotate it with the heads on & the rockers off so the valves stay closed if it turns the problem has to do with the valves .

[Mrbill426]

@gzig5  yes one the head gaskets had pieces stuck to the deck and both had oil soaked into them in a couple places so I ordered a new pair; cheap piece of mind.  I might have put too much lube on the bolt threads and I won't do that again 

I ordered a set of ARP bolts for an A-engine so I will at least have them on hand to decide on; again piece of mind.  Reading up on them it says they only have 9/16" heads compared to 3/4" on the stock bolts, and torque higher @ 100 ft lbs... seems high for a 9/16" head 

I hope I have it figured...

For a stock-ish build, I would re-use the head bolts with that few of cycles on them.  I didn't think that head gaskets were one time use unless they tore on removal or were run for a while.  If you got to have the peace of mind, stock head bolts and that felpro gasket aren't terribly expensive.  Glad you figured it out.

[MOPAR MITCH]

MrBill426 -- why are you using the 8553PT head gasket?  That gasket is thicker (at ~0.54)... and it was made thicker by Fel-Pro roughly 20 years ago simply to better accommodate machined heads/blocks.  8553PT simply has a folded over tin-plate cylinder armor... not very strong against detonation/pre-ignition for hi-perf engines (typically having higher CR, such as 10-1 or higher.

Your better choice is the Fel-Pro Performance 1008.. has a stainless steel armor folded over a pre-flattened internal wire ring... excellent performance gasket... compressed at ~0.39". 

I'm a past Fel-Pro engineer and very familiar with all gaskets.

[Mrbill426]

@MOPAR MITCH well mainly because when I cataloged replacement head gaskets for this relatively mild rebuild that was the number that popped up.  I am game for a better gasket but then being quite a bit thinner I wonder if I will then actually have piston-to head or valve issues?  After CCing everything and running the numbers I came up with about 9.5-1 CR assuming that gasket.  Want to stick with on the road available pump gas.

Thanks

MrBill426 -- why are you using the 8553PT head gasket?  That gasket is thicker (at ~0.54)... and it was made thicker by Fel-Pro roughly 20 years ago simply to better accommodate machined heads/blocks.  8553PT simply has a folded over tin-plate cylinder armor... not very strong against detonation/pre-ignition for hi-perf engines (typically having higher CR, such as 10-1 or higher.

Your better choice is the Fel-Pro Performance 1008.. has a stainless steel armor folded over a pre-flattened internal wire ring... excellent performance gasket... compressed at ~0.39". 

I'm a past Fel-Pro engineer and very familiar with all gaskets.

[RzeroB]

I know  you didn't do this, but your thread reminded me of a funny (it's funny now, but it was damn embarrassing when it happened!) thing that happened to a friend years ago. He put an engine together, installed it in the car, and then found that the engine would only turn over about 45 degrees of a full rotation. He could not figure it out the problem with the engine in the car. So he got some of the guys together and we wound up pulling the engine back out of the car. When we removed the heads, we discovered that the piston domes were reversed on the right cylinder bank!! This faux-pas caused the piston domes to make solid contact with the combustion chambers and prevent it from turning more than 45 degrees. Boy was he totally embarrassed, and mad at himself for making such a blunder!! 

[Mrbill426]

@RzeroB  Yikes ... yeah I have done some dumb stuff like that and probably will again.  Far as I know mine are orientated correctly with the valve notches up towards the lifter gallery.

I know  you didn't do this, but your thread reminded me of a funny (it's funny now, but it was damn embarrassing when it happened!) thing that happened to a friend years ago. He put an engine together, installed it in the car, and then found that the engine would only turn over about 45 degrees of a full rotation. He could not figure it out the problem with the engine in the car. So he got some of the guys together and we wound up pulling the engine back out of the car. When we removed the heads, we discovered that the piston domes were reversed on the right cylinder bank!! This faux-pas caused the piston domes to make solid contact with the combustion chambers and prevent it from turning more than 45 degrees. Boy was he totally embarrassed, and mad at himself for making such a blunder!!