My engine components are in my sig.

Basically I have the engine out now, and I HAD to take it out to get the heads off. So you can see that head gasket life is very important.

Will head studs do me any good in keeping a good seal on the head gasket?

 

Cap'n,

Properly torqued bolts will do just as well as studs. Start with new fasteners and clean holes.

Actually, if you think about it, studs have TWO sets of threads that can work loose, and are going to take up more space under the rocker covers. The benefit of studs can be that the finer top threads require less application torque to achive the same preload and elongation of the fastener. Studs with UNC upper and lower threads have no practical advantages over bolts.

If you are concerned over gasket sealing, make sure the surfaces are true and flat (no warpage). Clean the mating surfaces to like new condition (like the laquer thinner trick?). Avoid using thin gaskets or all-metal gaskets. Use gasket sealer sparingly if you think you need to use it at all (like copper seal). Apply thread sealant (like PST) to the bolt threads, then torque the bolts in stages, taking the torque to 50%, 80% then full torque through the tighteneing sequence. If there is a range of torque, try to achieve the upper end of the range for final torque.

 

so your saying that if i build up a turbo motor (approx 650 hp ballpark) I shouln't use studs and that bolts will be ok?

 

I see. The original head bolts only have 20k miles on them. If I chased all the threads and used more laquer thinner to clean them real well would that be just as good?

I'm using the head gasket that Dart recommends. I wasn't going to try and "cheat" to get the quench within favorable limits. I just want these to seal.

I am going to use Permatex #2 gasket sealer on the bolt threads. This is what my boss has done at work for 20 years, he said it's always worked for him.

The block deck looks brand new. I spend a couple hours today scrubbing one bank with scotch brite pads and it looks perfect.

Also, are head bolts something I need to retorque after so many heat-up/cool-down cycles?

thanks again Vader

 

retorque depends on the gasket you use, most don't any more. studs have a greater tendency to leak than bolts. i use teflon pipe sealer on the threads and under the head.

 

You can use either. The mere fact that it is a stud gives it no inherent design advantages over an equal bolt. A stud is, by design, no better or worse for retention than a bolt. They are both a cold forged metal rod with threads rolled on. The differences come in the metallurgy. Most factory bolts are more than adequate for the intended task. Higher quality aftermarket bolts or studs are typically a slightly higher grade alloy than their OEM counterparts. Cheaper aftermarkets may be actually worse than OEM (do a search for "broken rocker stud" and see what I mean). Factory bolts may have too much elongation for higher pressure engines, but that is due to the material, not the design.

And if you analyze, materials being equal, a stud may have some slight disadvantages in space required both during assembly and for the nut/washer after assembly, and in the potential for loosening.

 

The main reason racers use studs, is that when doing frequent rebuilds in between rounds, a stripped thread in a block is a real problem..... studs avoid that issue. As stated above, they offer no particular inherent advantage in clamping force or gasket life or any of that, and in a motor built with studs, you are virtually 100% guaranteed to have at least one that leaks.

IMHO using studs on a street motor is being a poser.

Just use good quality new bolts if you're worried about it, smear a small amount of hi-temp silicone around the water jacket holes in the gasket ONLY, and use Loctite PST or other non-hardening sealer (NOT silicone) on the bolt threads.

 

so now i know i don't have to spend like 600 on hardware, just about 300

 

To clean the bolt holes out I use a gun bore cleaning brush in a drill. A .45 cal brush would work for the head bolt holes in the block. I prefer the bronze brushes. Can also get them in nylon and stainless. Need to get a short piece of cleaning rod also.

Chuck into drill, spin at a moderate speed, spray a little solvent in and run up and down the threaded hole with the brush.

If rebuilding engines it is nice to have an assortment of brushes along with the regular rifle lenth rods. This allows you to brush out all of the oil passages.


As for retorquing heads, I always do it even if they are claimed to not need it. Not only better safe then sorry I've found that they always turn a hair more.

RBob.

 

RBob comes thru again....

I never really thought of using the bore brush. Looks like I'll have to break out the EAA .45 and borrow the brass brush.

ug, retorquing head bolts in my van is going to be hell. But, I only want to do this once...