Re: Is it recommended to use antisieze lube on head bolts - 89 Evirude 150 hp.
Will soon be putting the heads back on with new gaskets and I was wondering if anti sieze lubricant would be a good idea or not. Seems like it would be a good thing in this application but the manual doesn't mention it. If it were used, would the torque values still be the same as the manual states - 18-20 ft. lbs. ?
hello,
good question, imo. at 18-20 ft lbs i would only use a light engine oil [30 wt] application on the head bolt threads. for most engine torque applications that is the procedure. changing the procedure does require a change to the torque spec to achieve the same clamp load within the fastener's working envelope. but not to worry too much at 18-20 ft lbs.
i also like a tweak of engine oil under the head bolt and its shoulder so as to lube it as it turns on the head. the sides of some head bolts may touch [kiss] the head as they are turned. 20 ft lbs is not much friction, but 85 ft lbs is. i also like a tweak or a dot or two of anti-seize under the head bolt painted around with a used toothpick which will then act as a paint brush. note i said: "dot or two". i like it to comingle with the light coating of engine oil i put there.
torque specs are ballpark windows. actually bolt stretch is the more accurate way to set a head bolt. the key issue is to maintain a consistant clamp load on the head gasket.
and as was mentioned... always torque in proper sequence. if in doubt, start in middle and pattern a circle and go outwards. for 20 ft lbs, i would go 10, 14, 16, 17, 18, 19, 20. let it set 30 mins and ck again at 20. then after run in re check via 20 when warm enuff to touch engine. you can do it in 3, but this sequence loads the cylinder walls smoother from the bolt's twist and will help reduce bore distortion... which is present when any head is bolted on; studs distorting the least. bore distortion from head bolts in a cast iron block is measureable, hence torque plates for honing. even more so in an aluminum block depending on torque spec.
personally, i will ck mine routinely. i will set my t wrench at 20 max... and lightly pull wrench. i have 3/8th snap-on click click. i also add a bit of 3 n 1 oil to clicker side of wrench before using it. i would not trust a 1/2" pointer type torque wrench to set 20 ft lbs... if it even measures that low. but the 3/8" snap-on click click does it very nicely, very accurately... all else considerd.
but first, be sure u chase the block threads, blow with compressed air [goggles] chase or wire clean bolts, and i also then apply laquer thinner to block threads with Qtip and air blow dry... [again, goggles] i also clean head bolts in solvent and use compressed air. also a good idea to clean top of pistons of any carbon while in there...
the way i do the block is to use as much l thinner as i can get on the qtip. watch out for other painted surfaces. then i get into the treads, maybe even twice... then as long as the hole is a blind hole, i then put a wad of paper towel over the block hole, slip in air nozzle and short blast the residual crud out into the paper towel. laquer thinner and compressed air... keeps things
nice n clean.
ie: accurate torque readings.
regards
lakester
