Smoker

[Bronkster]

Engine smokes only at start up, but it puffs a pretty good blue cloud and it will be another season before I can build the 351 that I have. Consistent feed back leads to valve stem seals. My question is this something that is worth doing in the vehicle without removing the heads or since I need to do all of them should I take the heads off? Thanks for any input or advice.

 

[blubuckaroo]

You'll need to take the plugs out to change the seals anyway so while you're at it check the compression. If it's low, don't bother with the seal replacement. Just keep cleaning the plugs until the motor change.

 

[broncnaz]

Thats all kinda up to you. How many miles are on the engine? How much oil does it burn between oil changes? more than likely it also needs a valve job and probalby new valve guides. Best bet would be some reconditioned cylinder heads. But I agree with Blubuckaroo if the compression is low it may not be worth the effort.

 

[Broncobowsher]

The heads probably need to come off. Besides the seals being bad there is probably a bit of wear on the valve guides. New seals probably won't last with bad guides.

If I remember right, bad exhaust guides are smoky startup (oil runs down the guides when shut down). Bad intake smokes real bad on decel (strong vacuum pulls oil in)

 

[jurob]

valve seals are easy enough to change with compressed air. other then your time the seal change is a very inexpensive swap. i say change the seals and see what happens.

my experience with bad guides is extreme oil consuption. just like bowsher mentioned, during high vacuum situation bad quides will suck the oil right in.

 

[BUCKETOBOLTS]

I agree with 'Bowsher, the guides are probably the root cause. A set of seal may patch it for a while.

 

[Bronkster]

Thanks for all the help. I'll start with a compression check. I had a line on some fresh heads reasonably priced, but have heard that would probably blow out my bottom end. Not sure how many miles are on the engine, but I did put in a new timing set, and judging by the amount of wear on the gears I'd guess close to 100,ooo. Will heads from a 351w bolt on to my 289 block?

 

[needabronco]

351 heads if I remember right use 1/2" bolts, but I there is a way as it is a fairly common swap. BTW later 351 heads are the same as 302 heads, as far as chamber and flow...

 

[jurob]

351 heads on 289/302 use a reducer bushing washer instead of a regular washer. pops right in the bolt holes then the bolts go in.

new heads blowing out your bottom end? must be some badass heads! lol

if your worried about guides pull the springs and see if there is any play. no play, then put some new seals on and be happy.

 

[krisbassett]

I would also say do a compression test if it is low don't put new heads on it. The new heads will be nice and tight and could cause oil to bypass the rings causing even more oil burning.I say if it is not burning more than a quart of oil between changes don't mess with it at all unless to rebuilt the whole thing.

 

[doghauler]

Just did this job on mine, it sits a lot so the seals dried out I think. I have good compression all around so I thought I'd give the seals a shot. You can buy a tool that screws into the spark plug hole that you hook up to compressed air, hold the valves closed while you pop off the rockers/keepers, pull the old seals off and put the new ones on. You'll need the seals, the sparkplug hose thing, a valve spring compressor, and normal tools. Simple, quick and cheap fix if you have good compression. Fixed mine....