Valve seat in E-brock heads

[MOTORHEAD]

Anyone here ever have a valve seat come loose in an edelbrock head ? I think my #6 exh seat is loose, based on noise on that side of the engine after eng is warmed up. Listened to header pipes with stethescope and #6 has randome "clinking and clanking" noise which other cyl's do not.
Will be pulling exhaust later today to get a look.

[Jerry Clayton]

all the engines I've seen that had loose valve seats were ----------------------------

IF--------the valve seat isn't installed with the proper interference fit----AND --------the engine is shut off with the exhaust valve somewhat (only a little bit) open (off the seat) the seat could possibly drop down out of the casting, and would after the engine has cooled off---would cause excessive valve tappet clearance which would then be a noise you could hear-

Suggestion is to remove the valve cover and check valve clearances-if you find excessive clearance then look for the cause-----

Of course, if you are running flat tappets, it could be a lobe wiped out---------

[MOTORHEAD]

Thanks Jerry,
FWIW i'm running hyd roller. This problem seems to have started after I was doing high RPM
(but not over 5k rpm) runs to ck afr while jetting the webers. Although thewater temp never went over 90c, I did experience some afr's of 16:1 +, which may have resulted in high cht's .

[Jerry Clayton]

So you possibly could of shut it down while there was an extremely high temp on that cylinder??? Webers---tune individual cylinder-------------

I'd still check valve lash before you disassemble it---------

[CHANMADD]

5000 rpm is not high revving.......I put my foot down at 5000........

[Jerry Clayton]

exhaust temp will be 1600 +_ with 16-1 afr and the seat could come out of the alum if shutdown with that valve open which will increase the clearance causing clicking---if it is out any appreciably distance the piston will hit the valve and soon the seat and/or vavle will be destroyed followed in short order of the cylinder head and piston-----

At least with Webbers you won't have pieces flowing backwards thru the intake into other cylinders-----------

[MOTORHEAD]

Valve train is all tight (hyd lifters). Plugs on this bank (5-8) are all oil fouled, 1-4 are not. Took headers off to inspect exh valves, could not see seat or valve heads, only end of guide, stem. Chambers coked up too much for 600 mi. #'s 5&6 have a very obvious oil path comming out the port, actually dripping from # 6. Also cold cranking comp test is lower than previous on those two cyl.
Guess I'll pull intake and head.

[ERA Chas]

If it's not the intake gasket pulling oil, it's the stem seals. Remove the Shelby teflons and replace with vitons. Barry R can supply them. The intake gasket should be a 1247-S, also from Barry.

[Jerry Clayton]

You can replace the seals without pulling the head---------------

[blykins]

Yep....

If you need a set of Viton valve seals, I'll send you a set...no charge.

[Jerry Clayton]

Nice Brent-----------Reading this as I have my first coffee of the day--------might be a classic F up---original valves were 3/8 and the Edelbrock are 11/32? the wrong seals could of gotten installed on the head on that side-----about one of the only things that would cause something like that on one side and the other be differant

[blykins]

It's possible, but my money is on a bad intake gasket.

[Jerry Clayton]

How much do you wanta bet?????? I'll pick you up and we'll head down there----------after I get another cupajoe

[MOTORHEAD]

Jerry: Coffee's on ! Come on down !!

ERA: was told and shown by eng shop builder the seals are viton.

Jerry: stem measures .370 above keepers/retainer.
My on-the-car spring comp only grabs outer coil, the inner and damper float, doesn't work very well. I could fab a rocker shaft sub and use a lever type I suppose.

[blykins]

I've got an FE-only on-the-head spring compressor that I use for when I break-in and dyno flat tappet stuff. There's a guy on Ebay that sells them....about $75, but they work really slick.

[MOTORHEAD]

The other possibility is a lifter intermittantly collapsing.
The noise is not there when eng is cold, only after up to temp.
The oil in comb chamber is the secondary problem, the source of the noise is the primary concern, and with the possibility of major damage being done if the seat comes out and jams the valve, I feel the only prudent thing to do is tear down the top end.

[MOTORHEAD]

here's some pics:

[MOTORHEAD]

Jerry: recognize this ?

[Jerry Clayton]

Yes I do----------I wish there had been a way to remove that without damaging the body----------how did the combos work out????????

Scott might see this also----------

[scottj]

Originally Posted by Jerry Clayton

Yes I do----------I wish there had been a way to remove that without damaging the body----------how did the combos work out????????

Scott might see this also----------

I see everything Jerry... lol