Hello from France

I reassemble the cylinder heads of my 454 of 1973.

Certain bolts of cylinder heads soak in the liquid of cooling and to avoid the increase, I will apply to threading produces it ARP 100-9904 (thread sealer teflon based). Thank you with several members for the Corvette Forum for this council.
The bolts of cylinder head which I willl use are bolts of reference ELGIN EHC-201S like those http://www.autoperformancepartsbyobr...dsh-454/Detail

On the original sercice manual of my Vette, the torque specification is of 80 lb.ft to tighten the bolts of cylinder head. The application of the ARP 100-9904 changes this measurement.

I asked ARP which are the news torque specifications with the addition of their Teflon based thread sealer. ARP cannot answer me and asks me to put the question to ELGIN.
I thus put the question to ELGIN but I don't have an answer.

Who can help me and give me the new torque value adapted to my situation

THANK'S VERY MUCH


Charly

 

I do not believe applying thread sealant changes the torque specs. 80 foot pounds in three steps is correct. Bon chance.

 

Applying a teflon based sealant to the threads is essentially "lubricating" the threads. Torque value for 'lubricated' threads is usually about 1/2 of the 'dry' torque spec.

Another way to set the proper tension in those bolts with sealant is to torque to an angle set position. The concept is to bring the bolt down to where it just takes up all of the slack in the system (with a thin metal head gasket, there is very little 'crush' factor to worry about; if you have a thicker gasket, you will have to experiment a bit).

For those bolts that you do NOT put sealant on (dry torque setting), draw them down to solid joint condition with only about 5 ft-lbs torque on them. Now, remove the torque wrench and place a mark on the bolt head at the 12 o'clock position. Reinstall wrench and torque to 80 ft-lbs. Remove wrench and estimate how many degrees of rotation the bolt made during the final torque setting process. Do the same for all of the 'dry' torqued bolts. When done, make your best estimate of the average angle of rotation made during that last torquing operation.

Now, for the bolts with sealant applied to them: install the bolts, run them down to solid and then to 5 ft-lbs. Now, turn those bolts the same rotational amount that you turned the dry bolts. Because of the identical screw thread configuration on all the bolts, that amount of rotation will put the same tensile stretch into those bolts with sealant added...regardless of the amount of actual applied torque. You can measure the actual torque applied during that process, if you want; but you need to quit turning after reaching the established degrees of rotation required.

P.S. In the present day, many industrial assembly facilities use 'torque angle' to set bolt tension, rather than simply using bolt torque as was done for our C3's.

 

Thank's with you two for your information .

Charley, cheer for this quite detailed “lesson” ..... I very understood ….it remains to me to apply all your councils ......

Have a good day

Charly

 

here is a link from a head gasket manufacturer, it covers what to do with bolts going into water passages.

http://www.felpro-only.com/tec_notes...rque-Guide.pdf

 

Mel,

I looked with much interest the link that you sent me in your answer and I actually read the need for putting a thread sealer on the bolts (page 7)

Thank you for all

Charly