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  If you have not learned by now,  this old stuff that I love drives me crazy because we have made a lot of advancements since our cars were built, and I have a hard time just putting it back like it was.  My 1925 Buick has head bolts.  17 bolts, but 2 are actually studs.  They screw thru the top of the block and into the water jacket.  The threaded holes at the top of the cylinders are not blind holes.  They go into the water jacket.  From what I can tell, you have to use thread sealant on the head bolts.  I purchased Permatex head bolt sealant.  I am not sure what they originally used, but you have to use something like this on the head bolts and manifold studs.  I am also of the school that it is a good idea to retorque heads after say 5-10,00 miles.  Not sure if my car will ever see that.  If I buy new head studs, then I can use the thread sealant, and if I retighten the head, it will not effect the seal on the base of the stud as only the top nut will turn.  If I use the bolts, it would not be a good idea to touch the head bolts at a later date for fear that I could have a leak from breaking the thread sealant seal.   Just looking for some opinion on this, and if anyone has any thoughts on head studs.  7/16 x 5 1/4" long.  They were not inexpensive.     Hugh     

 

1936311986_HeadBoltSealant.thumb.JPG.1e04b85920f9c79b5154c00b7f989c98.JPG

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Hugh,

    I have never seen leakage from head bolts in any of my Buicks.  However, if you want to be sure, just use a non-hardening sealant.  Also, pay attention to the difference between dry and lubricated torque settings.  I suggest you re-torque the head bolts after the engine has run through one or two heat cycles. 

Waiting to do it after 5-10,000 miles is not necessary. 

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Hugh,

Boy, am I glad that I have caged-valve engines in my Buicks?.  Just kiddin' a bit there.  I will assume that you are going back with new head bolts where possible.  Your comment about the cost was noted.  I am of the opinion that it is a good idea to replace nuts and bolts during a restoration like this for the simple reason of the stress that has been placed on the threads.  Did you replace these bolts with at least Grade 5?  In my humble opinion, I do not think it wise to use a lesser fastener.  Mark is right on as usual about the thread dope.  On my 6-Cylinder engine blocks, the manifold studs, rocker post studs, and the water inlet tube tapped holes are in the water jacket area.  I am not going to replace the studs as they are in very good condition on the 1916 block that I am working with.  I will be using a thread sealer on the machine bolts that hold the water tube to the side of the block.  The studs in this 1916 block have been in there for going on 104 years without any problems.  I ain't gonna kick that sleeping dog.

 

Terry Wiegand

South Hutchinson, Kansas

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In my 1940, the head bolts had blind holes, they didn't go into the water jacket.

 

I know this for a fact because I used Duster to clean the gunk at the bottoms of the holes. It's a trick I invented, I was worried that if there was any gunk at the bottom of the blind holes, the bolts would not go in all the way as they bump into the gunk, and you can't torque the head bolts right.

 

Duster is a can with a straw on the tip of the nozzle, that you buy at Staples, that normally shoots out gas at high velocity, but if you hold the can upside down, it shoots out a liquid. Turn the can upside down and put the straw to the bottom of the bolt hole, and squirt the liquid into the bolt holes and the gunk shoots right out at high velocity, and you just wipe it off. The liquid turns to gas in a fraction of a second and it's really cold. You freeze your hands off but it gets all the crud out super clean.

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So here is a game plan that I am moving on.

I don't want to use the locktite "head bolt and water jacket sealant"   This looks like just red locktight.  I am not convinced that antifreeze will not leak thru the threads if the bolts are retorqued.  I think I want to use a teflon based thread sealant.  This stuff is non hardening.  

I did find 7/16 head studs.  The original are 5 1/4" long and they have 3/4" long 14 pitch base threads.  All of the head studs now thread up 1" at the bottom,  so I went with 5 1/2" long.  Now it appears the company only has 13, and several other companies also indicate only having 13, so I just hope I can find 4 more somewhere than in this one warehouse.  I did eventually find the studs for $5.50 each.  

392748081_ARPHeadBoltThreadsealant.thumb.JPG.9f154234f28668afdc984ee37beb1d33.JPG

 

 

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19 hours ago, Hubert_25-25 said:

So here is a game plan that I am moving on.

I don't want to use the locktite "head bolt and water jacket sealant"   This looks like just red locktight.  I am not convinced that antifreeze will not leak thru the threads if the bolts are retorqued.  I think I want to use a teflon based thread sealant.  This stuff is non hardening.  

I did find 7/16 head studs.  The original are 5 1/4" long and they have 3/4" long 14 pitch base threads.  All of the head studs now thread up 1" at the bottom,  so I went with 5 1/2" long.  Now it appears the company only has 13, and several other companies also indicate only having 13, so I just hope I can find 4 more somewhere than in this one warehouse.  I did eventually find the studs for $5.50 each.  

 

I would buy Grade 8 bolts and use them for new head bolts.  Cost about $1.25 each at the farm store. I know of a couple of cars that are using them now.  Here is what I use for a sealant.

 

GM Oil, Fluids, and Chemicals - GM 12346004 - Liquid Teflon Sealant 50cc Tube

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I like the larger head bolts on the outside of the rocker cover where you can see them.   I bought new bolts for inside the rocker cover where they can not be seen and used the best of the old ones  where they can be seen.  

 

I have always used Permatex #2 to seal the head bolts.

 

Like Mark, I only re-torque it after a couple of  short runs.   I have not had any head bolt leaks.

Fred

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Pete, 

    I had a recommendation from my machinist that line bored my block to not go over 100 ft lbs for my 1925 Standard on the main bearings.  There were no actual torque specs in the 20's and most of what you see is from the late 30's or early 40's, and I am sure there were improvements in the steel quality as time marched on.  So I have modified the information I received to what I feel more comfortable with using for my car.  Also note the very odd bolt tightening sequence that the "Antique Auto parts Cellar" chart suggests for Buick.  My recommendation is to use the recommended bolt tightening sequence that Buick used in the 1951 shop manual on the straight 8, still an odd pattern to me, but you delete the end cylinders in the tightening sequence.  Also note the main bearings were 95-100 ft lbs in 1951.     Hugh

1112525964_TorquespecsBuick1.thumb.jpg.155e27a5799016654b3031cb0829adac.jpg

 

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  • 1 year later...

I put a couple of hundred miles on the rebuilt 1925 Buick Standard motor and it is time (or past due) to retorque the cylinder head.  The original torque was easy prior to installing the rocker shaft.  The rocker shaft above the cylinder head covers one row of bolts.   The worst spot is where the oil feed pipe is attached at the rear of the cylinder head.  I used an 11/16" crowsfoot line wrench to keep from having to remove the rocker shaft.  I did have to modify the wrench slightly to prevent damage to the oil feed piping.  I progressed slowly to ensure that the rachet extension always had room to travel and did not run into the rocker shaft and effect the torque.   I did a pass at 50, then 55, then 60 ft lbs.   I used the crowsfoot wrench on all bolts for consistency, even though I could put a socket on some of the bolts.  I did the torque with the crowsfoot perpendicular to the torque wrench to keep the load the same.   

There are 2 different torque sequence diagrams shown above.  Both are for the straight 8.  Both are unconventional looking IMO.  Taking a cylinder off each end does not have the same bolt pattern as the early Buick 6 motor.  On my photo you will see the tightening sequence that I used.  After this, I adjusted the valves again to the wide setting of .08 with the motor cold.      Hugh

 

  1890404823_Torquecylinderheadtightening2.thumb.JPG.cf6eb81c3d7348dbfc7b6ee6dfa5e878.JPG      

Edited by Hubert_25-25 (see edit history)
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