Oct 11th, 00, 07:55 PM
I have a set of 186 casting heads with stainless valves,k-line bronze guide inserts screw in studs ,guide plates.The heads have just been fully ported polish exh etc..Very recently I bought a conical spring set from comp cams which came with umbrella seals.My head guy says he will machine my heads to accept p\c teflon seals.Is there an advantage between one or the other???He will also macine my pockets for a dual spring if I want.The machining is free cause we horse trade!!!Lift on cam is 0.480 conicals rated to .500.I want to do it right!!Are duals with dampner better???Thanks
Oct 11th, 00, 08:49 PM
Hey Long Rod,
You said your lift is .480, but you didn't say any more about your cam. If you are running a hyd cam the single springs will work. If you are running solid lifters use dual springs.If you are running a roller machine the pockets and run triple springs.
Look at your cam card, and most cards have the recomended springs and the spring pressure at a specfied assy hiegth.
About the seals, I have run both, and the o ring seal has been succesful for many years. The PC cup seals keep oil out of the guides, but I have often wondered if they keep the guides to dry and actually increase ware from lack of lube in the guide,just thinking out loud.
Mark W. Winning
Oct 12th, 00, 05:14 AM
You should not have to have the pockets machined for your springs. I am running a 488/510 lift Edelbrock cam on the 186's and did not have to machine them. Have your springs tested to make sure you are with spec though. Our machine shop had springs there that worked great.
1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
Oct 12th, 00, 04:04 PM
Bottom line is... you have to match the springs to the camshaft you are using. Double, single, triple...it does not matter as long as the seat pressure and the spring rate is correct for your cam. Most cams up to about .500 lift will work just fine with the stock diameter Z-28 springs or anything similar, like the Comp Cams 981's.
By the way, you cannot just machine the 186 heads out for a bigger spring in the traditional manner. You WILL hit water. You have to put a spring shim in the spring seat area and then machine down to that level, actually leaving a step in the head. You still get very close to the water jacket.
Find out what springs your cam calls for, and go with them.
Hope this helps,
Advanced Automotive Machine
Oct 13th, 00, 08:35 AM
Anyone want to sell a set of 186's I need a set for my 70 Z28. I have used the conical springs before (was not impressed). Like Bill said BE CAREFULL CUTTING THE SPRING SEATS. There are plenty of stock style springs that will work up to 550 lifts. I would at least run the Z28 or comparable spring that is usually good to 510 lifts. As for the valve seals, I have ran them all from umbrella to both styles of PC seals. The umbrella seals would be fine however, I would say if the heads are apart and he will machine for free "go for it" One word of advice get the Crane PC seals as I have had trouble with Comp Cams being hard to get on (real tight fit).
68 RS Rally Green Camaro, 70 RS/Z28, 70 SS396 Chevelle, 97 SS Camaro