It appears I have a bad exhaust valve on one cylinder of my new motor. So I plan on pulling it this winter to get it checked out and fixed. The motor will have less than 10,000 miles on it. Any suggestions on what else I should do to it while I have it out. I will be pulling the motor out of the car to make it easyer to fix a leak in the back.

 

cam - really big cam
cr - as much cr as you can handle
heads - big heads
pistons - big domes
crank - stroke it to he max 4.7 i think

ok all kidding aside

a better cam, post the heads, poss 4v valves and or aussie heads
the standard stuff.

 

It has KB hyper. 10:1 Compression. aussie heads with 4v Exhaust Valve. Roller tip rocker. A special grid cam. I'm not planning on changing anything. The car runs really good on 7 cylinders. I was just wondering if I should check, cleanup, or change anything in process while I had the heads off and the block on a stand.

 

[updated:LAST EDITED ON 13-Aug-02 AT 09:56 PM (EST)]windage tray
block girdle & main studs
weld baffle(s) in oil pan
heavy-duty oil pump driveshaft
blueprint oil pump
arp rod bolts
high stall torque converter
grind something - anything!
trick out the carb
leave the motor alone - do rear disc conversion on car
install 4.11 gears, detroit locker posi & 31-spline axles
aluminum radiator & electric fans with fancy relay control system
trick ignition
mill the block deck surfaces to decrease piston/deck clearance
replace all control arm bushings, ball joints, tie rod ends, body bushings
convert to serpentine belt & underdrive pulleys
'67-'68 cougar tailight conversion
install glass sunroof
narrow rear frame rails, install ladder bar suspension
cut out rear wheel wells, install tubs, NHRA-legal cage
raccoon tail on antennae
scrub underside of car clean from bumper to bumper, paint or undercoat
line-lock
re-do interior
new stereo & CD changer
clean & paint engine compartment
fix bad wiring
clean & paint engine accessory brackets, oil pan, valve covers
replace heater core
strip paint from windshield wipers & repaint if they're not stainless steel
get a chick in the back seat
restore original jack & spare tire
buy a couple of cases of beer, ice it down, invite some buddies over to stand around in your garage, look at your car, and make ridiculous suggestions like the ones above...

 

I'm wondering why the valve went bad and why you went with 4V exhaust valves. Is the intake valve 2V, multi groove type?

 

Ya I'm yondering why it went bad as well. I went with a 4v exhaust valve because that's the cleveland weak point in the flow. I've heard since you can also do the intake if you unshroud it. I don't know what type of valve were used as far as grooves are concerned. I had the work done last winter by someone I thought new what they were doing.

 

>windage tray
>block girdle & main studs
>weld baffle(s) in oil pan
>heavy-duty oil pump driveshaft
>blueprint oil pump
>arp rod bolts
>high stall torque converter
>grind something - anything!
>trick out the carb
>leave the motor alone - do rear disc conversion on car
>install 4.11 gears, detroit locker posi & 31-spline axles
>aluminum radiator & electric fans with fancy relay control
>system
>trick ignition
>mill the block deck surfaces to decrease piston/deck
>clearance
>replace all control arm bushings, ball joints, tie rod ends,
>body bushings
>convert to serpentine belt & underdrive pulleys
>'67-'68 cougar tailight conversion
>install glass sunroof
>narrow rear frame rails, install ladder bar suspension
>cut out rear wheel wells, install tubs, NHRA-legal cage
>raccoon tail on antennae
>scrub underside of car clean from bumper to bumper, paint or
>undercoat
>line-lock
>re-do interior
>new stereo & CD changer
>clean & paint engine compartment
>fix bad wiring
>clean & paint engine accessory brackets, oil pan, valve
>covers
>replace heater core
>strip paint from windshield wipers & repaint if they're not
>stainless steel
>get a chick in the back seat
>restore original jack & spare tire
>buy a couple of cases of beer, ice it down, invite some
>buddies over to stand around in your garage, look at your
>car, and make ridiculous suggestions like the ones above...
>

I must be in good shape. Except for the drag racing stuff I think I've done most of these. I think I'll go put in a new fuel line.

Thanks

 

The multigroove valves are OE on all 351C/351M/400 except 351B. They are supposed to help rotate the valves so they last longer, but can sometimes break.

The intake to exhaust flow ratio is not that bad on the 2V heads. It's the 4V heads that have the bad reputation.

I know www.powerheads.com put 4V I & E valves in their Assie heads and claim some big improvements but I've seen another source state that a larger exhaust valve did nothing to improve flow.

Consider stainless exhaust valves if you don't have them already. The 2.19 4V intake valve is overkill on a 2V head. A better compromise is the 460 valves. 2.09 vs 2.04. They are common and use the stronger single groove keepers.

 

>The intake to exhaust flow ratio is not that bad on the 2V
>heads. It's the 4V heads that have the bad reputation.

Wouldn't be nice if you could get the same information. I've also heard conflicting info on flow. I went with a chart I got off the web last year that compared the flow rates of different heads as well as the clevelands. It showed the best flow for the cleveland with the Aussie heads and 4v valves.

Kinda makes you wonder what's real.

 

[updated:LAST EDITED ON 14-Aug-02 AT 06:28 PM (EST)]If you search this board, someone posted his first-hand experience with intake valves and Aussie heads. IIRC, you grind 4v valves down slightly and cut the seat for a 30^ seat. I think the original poster stated something about the seat width.

Seems that 4v valves are shrouded by the combustion chamber and cylinder wall, and cutting the valve down a little yields the best results.

Edit: I found this from MrMotorsport in topic #800 on this forum;

Or, another option that has worked for me: Have the existing seats cut at 30-degrees. (from the standard 45-degree seats) You will need a set of 4v valves cut down accordingly to match the new 30-degree seat, but don't have the machinist open the seat any larger in diameter, just cut for 30-degree seat, with a 45-degree under the seat, then 60 degree blended into bowl. Your valve size, after cut down for new seat, should be approx 2.10 or so. Not much bigger than factory valve so shrouding is not dramatically increased, but I gaurantee low lift flow increases..........Just one of my little secrets...... - Don, New York

 

Changing valve seat angles are way beyond my skills. I would need several experts to talk me into it.

Shrouding is a problem with a 2.19 intake. That's why the cylinders are notched. Even so, it flows a lot so the exhaust is a bigger concern. I'd prefer 2.15 intake so there is more room for a 1.75 exhaust. It depends on the cam choice.

460 valves are 2.09/1.65. I like their size for the 2V head but 2.12/1.71 would be my next choice. I don't know how fae a 2.19 can be cut down.

If you aren't comfused enough yet try,
http://www.rehermorrison.com/techTalk/indexStart.htm

 

If you aren't comfused enough yet try,
http://www.rehermorrison.com/techTalk/indexStart.htm

I meant this one about Flow Bench Fallacies,
http://www.rehermorrison.com/techTalk/16.htm

 

That's a pretty interesting article. I guess the only way to really tell is bolt on a bunch of different setups and run them on the track or the dyno.

 

Hello guys,

well looks like installing 2.19 and 1.71 valves into aussie heads is what i am going to do. Why you guys say it would be overkill? my machinist told me the bigger the valve, the better... so isn't swapping from 2V valves to 4V valves a good move? why all the fuss to pay extra money to get the valves cut down ? the valve seats are shot anyways, so best bet is to install bigger valves. just my 2 cents.

Werk


GMC = Generally Misconstructed Crap

 

[updated:LAST EDITED ON 15-Aug-02 AT 02:24 PM (EST)]how good it works depends on a lot of things, which is probably why some people say it works great, and others say no improvement.

how you blend the new larger throat into the old one is going to make a big difference. and of course you'd rework the area around the guides as well, and probably do some port work too. the seat angle and width is going to make a difference, plus doing a 3-angle job, blending into the throat and chamber, and backcutting the valves. you can decrease shrouding by widening the side of the chamber out to close to where the gasket will be, and doing the same thing at the top of the bore. just make sure you don't cut the bore down far enough to get into where the top ring will get into it, and don't cut the chamber or the bore back enough so that even a sliver of gasket isn't going to be sandwiched between the head & block. it's probably a good idea to do that kind of stuff before the machining. for the heads, take them in and get the throats enlarged first (about $8 each). then do your work on them, and when you're all done, take them back for the valve job. i've seen some nice looking 1-pc forged & polished stainless 2.19/1.71's on ebay for about $120 shipped. all the ones i've seen are single-groove keepers, which is the way to go. if you're VERY careful, you can do some light touch-up blending from your port/chamber work to the outside angles with a dremel after the valve job. very careful!

i thought the big block valves had 3/8" stems, instead of 11/32"

i'm not sure about valve length for 335 series motors, but chevy +.100 length valves are pretty close for windsors, and about 2/3rd's the price - just have to consider the installed height (about .05 shorter i think) when choosing springs, and chech pushrod length & rocker/valve geometry. there is a 2.08 available for those, and it's not hard to find them with undercut stems. i saw some flow data that showed a 16cfm increase on 4v heads, changing from "regular" valves (?) to undercut.