ejm

for a strictly off the street motor will it hurt to leave the seals off the valves? i know it might smoke a little but any other problems?

TS1955

I usually run them on the intake side only. JMO

TS1955

wmeabates

If your going to be using a crankcase vacuum pump it will dirty up the oil quicker with no exhaust seals and a lot of vacuum.Bill.

Tod74

Why do people leave them off the ex? My Brodix heads came brand new with no seals on the exhaust valves. Just curious what is the advantage in doing this.

zipper06

I don't run seals, if you remember chevy never put seals on their gides, just an O ring under the keepers and this on a street engine. The guides needed a little oil to keep them from wearing, and most did after a 100,000 miles, IE the little bit of blue smoke on cold startup on and old engines. Ford ran a little mushroom bonnet type seal, which is what i use on uncut heads. With the advent of bronze guides and alum heads they came with seals, because the guide were an oil impragnated bronze, but on strickly racing engines we cut back on the oil to the top of the engines, with roller lifters and rockers, and usually only a mist of oil on top, that why i don't use them. But as mentioned in an above post, if you are running a vacuum pump, they are probably a necessary idea. I've only ran an evac/header system, no experience with vacuum pumps.

JMO

Zip.

ejm

so f i run evac tubes to the headers like i have been then it will be alright to leave off? it goes 300 feet and the oil is changed every pull anyways
thanks
eric

kwkracing

Leave them off and dont worry about them.

chpseat987

I have talked with several old timers on this subject, and last season Mike strausberg was at our track, his mechanic builds my friends Engines and I asked them this question. They build all race motors, NITRO, or race fuel withOUT EX valve stem seals. They said " The Ex valves do alot of work and take alot of heat, so not running the seals gives a little extra room for oil on the stems for lubrication and cooling, they can get more life out of them this way. I ran seals on them last year but when I re built my heads for this season I did not install them. I hope this helps and makes since.

I also questioned my machinist and he also agreed as long as its not a street motor dont run the seals on the Ex valves.

ejm

so when i put my heads back together should i get some for the intake or let them ride too?

obsessedtruck

Id leavem off.. Especially with a triple spring. They usually get chewed up. I dont remember the last time i had seals. Remember our 300' pass is ALOT longer than a 1/8 or 1/4 run. Stuff has more time to build heat.