Cylinderhead work - please advise

[thethee]

I haven't been able to check the compression another time but I do have another (hypothetical) question for now. The original steel head gasket is 0.020" compressed thickness while the new composite gaskets are 0.039" compressed thickness and new steel gaskets appear hard to come by. Just ignoring the compression drop with the composites for now, would that be a straight swap? Or am I right in assuming you'd need new pushrods for that 0.019" increase? Alternatively, would milling the heads an additional 0.019" also work?

 

[CBODY67]

Milling the heads also affects the alignment of the intake manifold on the heads. There is a formula of how much to machine off of the intake manifold flanges per how much was machined off of the cyl head. Once done, you have a matched set.

With hydraulic lifters, no need to worry about the thicker head gasket. The loss of compression is very minor, all things considered, especially on a normal street engine. It can also make it a bit easier to run modern lower Research Octane fuels, too. Although some used to claim that it made about 1/2 point of lost compression. Which also means you can add a few extra degrees of initial base spark timing, too.

Just some thoughts and observations,
CBODY67

 

[max1196]

Shim gaskets are available. Mr Gasket part # 1135G .020 thickness

 

[thethee]

Milling the heads also affects the alignment of the intake manifold on the heads. There is a formula of how much to machine off of the intake manifold flanges per how much was machined off of the cyl head. Once done, you have a matched set.

With hydraulic lifters, no need to worry about the thicker head gasket. The loss of compression is very minor, all things considered, especially on a normal street engine. It can also make it a bit easier to run modern lower Research Octane fuels, too. Although some used to claim that it made about 1/2 point of lost compression. Which also means you can add a few extra degrees of initial base spark timing, too.

Just some thoughts and observations,
CBODY67

Good point, I hadn't thought about that yet. So the thicker head gasket won't affect the stock lifters and pushrods so much, but will it throw off the intake alignment? Or would that also be okay?

 

[thethee]

Shim gaskets are available. Mr Gasket part # 1135G .020 thickness
View attachment 524631

Thanks, looked at those and with shipping and taxes I'm close to 150 dollars unfortunately

 

[SuperDave]

Good point, I hadn't thought about that yet. So the thicker head gasket won't affect the stock lifters and pushrods so much, but will it throw off the intake alignment? Or would that also be okay?

For a street motor, the misalignment shouldn't be noticeable. The bolts may need some "encouragement" to get started though. On a race track or the autobahn, you may not get top end like before because of the mismatch in the intake ports causing turbulence.

Cbody76 is correct about hydraulic lifters, they are forgiving of a few tenths of an inch. Now if your running solid lifters, yeah you would hear ticking and lash adjustment would be off.

But don't forget though, the new gaskets may crush some and once installed be a lot slimmer than original. And for safety sake, I like to retorque the heads anyway after the 1st day, even if it's only a short trip around the block. You need to get it up to full operating temps then cool down again, let the heads settle in, then retorque the bolts. That'll help with the crush factor, squeeze the gaskets another thousandth of an inch or so.

Fresh head bolts might not be a bad idea, if you're not the original owner, there's no telling if it's been apart before and if the head bolts were reused, they may have stretched.

Just my 2 cents.

 

[Big_John]

Good point, I hadn't thought about that yet. So the thicker head gasket won't affect the stock lifters and pushrods so much, but will it throw off the intake alignment? Or would that also be okay?

The thickness of the gasket won't matter. You have to remember that these engines have manufacturing tolerances that can "stack up" and there's enough built into the process that allows for "stack up" (an actual industry term) so it all bolts together and runs.

If you look at a lot of things, valve stem and rocker wear, varying valve stem heights, crappy rocker arm stampings, cam base circle diameter variances, and on and on, you'll see that the lifters are capable of compensating for quite a bit of variances.

Regarding gasket material, the composite gaskets will seal better and will not need to be retorqued. They will compensate for irregularities in the head and block surfaces. When (if) you pull the heads, you'll see dark spots in the steel gaskets, especially between the cylinders, where combustion blow by has started. I don't think I've ever seen a factory built 440 engine come apart that didn't have those black spots, just some worse than others. I started using composite gaskets when FelPro came out with the Permatorque (sp?) line back in the 70's. Never had an issue with them.

If you are worried about losing that slight amount of compression, the thing to do is have the heads milled to compensate. Taking .020" off is nothing, and having the heads resurfaced is part of doing the job right anyway. A lot of places use a purpose made belt sander to resurface the heads, so strapping them to the milling machine might cost a few more bucks (or is it Euros?) but that will take care of both straightening and bringing back the compression. Really though, IMHO, it's not enough to worry about for this engine.

 

[thethee]

This is awesome, thanks guys, the picture keeps getting clearer.

 

[thethee]

I think I found a machine shop IF I decide to pull the heads. They sent me some pictures of what they're used to work on:

 

[thethee]

Got yet another question for you guys, this time about the head bolts.

This engine still has the steel shim head gaskets so I think it's safe to assume the heads have never been off this engine. I replaced the valley pan last year and the intake bolts came loose pretty easily. Can I expect the same from the head bolts or do those have the tendency to get locked? If the latter, is there a best practice to get them off without breaking them?

I wouldn't want to have to pull the engine to fix a broken head bolt just because I had a bad valve.

Just some of my considerations

 

[SuperDave]

They're gonna be stiff to turn. You're gonna want either a breaker bar & a cheater pipe to give extra leverage, OR an impact gun. I always reach for the latter. I'm too old to pull a muscle fighting a bolt.

These had to ensure positive clamping force to secure against full throttle pressures (hundreds, if not thousands of psi), so it's a safe bet they are pretty secure.

If you're using an impact gun, you're gonna want impact sockets too (the black ones). I have cracked many a chrome socket on an impact gun. Might as well get the deep sockets, they're useful for double duty on lug nuts. DON'T use them for motor reassembly, you can't dial in torque on a gun, either electric or air powered. If you don't already have one, for head bolts your going to want the 1/2" drive, 300 lb/ft gun. A 3/8" 150 lb/ft gun won't cut it.

 

[thethee]

Okay so I shouldn't be worried that they might be seized when they're stiff to turn, good to know

 

[Big_John]

Got yet another question for you guys, this time about the head bolts.

This engine still has the steel shim head gaskets so I think it's safe to assume the heads have never been off this engine. I replaced the valley pan last year and the intake bolts came loose pretty easily. Can I expect the same from the head bolts or do those have the tendency to get locked? If the latter, is there a best practice to get them off without breaking them?

I wouldn't want to have to pull the engine to fix a broken head bolt just because I had a bad valve.

Just some of my considerations

I've taken a bunch of big block Mopars apart and never had a problem.

They don't go into the water jacket, so there's no issue with rust or sealant. You can use a breaker bar or an impact. The impact has the advantage of fast and easy, but the breaker bar has the advantage of being able to find a problem with a random bolt or two. That was something I learned from an race engine builder I really respected years ago. He never used an impact to break down head and main bolts. His car consistently held NHRA records, so we can safely say that he knew something LOL. Breaker bars are also cheap too.. I used one (breaker bar) with an impact socket as that was a 6 point and not as likely to slip.

I never needed a cheater bar on my breaker bar to do this myself, but your mileage may vary.

Please, please, don't use a torque wrench as a breaker bar. I'm always amazed at the so called "experts" that do this.

Regarding putting it back together, I use one of these to clean up the tapped holes. Amazon product ASIN B00DTEFSWYEveryone used to use a tap (I did too) but these don't cut into the threads like a tap can. Also very handy to have in your toolbox.

 

[thethee]

Excellent, one less thing to worry about