113 casting max lift
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Joined: Mar 2006
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From: Lawrence- Rock Chalk, Jayhawk. KS
113 casting max lift
I would like to Know what the consensus is for max lift on stock 113 casting heads before retainer to valve guide interference is an issue. This is assuming new springs such as comp cams 941's (or insert your recommendation here, looking to get around .525 lift with hyd. roller) set at a installed height of 1.75 and a safety margin, of what, .06, with coil bind at 1.13
I realize the only true way to know is to measure, and that heads vary from set to set but I am interested in what has been your experience. I have kind of always heard that on most stock heads you can get away with around .480 lift, but I have also heard that the 113 casting may have a little more room cast in.
I realize the only true way to know is to measure, and that heads vary from set to set but I am interested in what has been your experience. I have kind of always heard that on most stock heads you can get away with around .480 lift, but I have also heard that the 113 casting may have a little more room cast in.
Race Director
Joined: Jan 2008
Posts: 16,028
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From: oregon
the other question is where the flow stalls. I ported the living hell out of a set of 113 castings, used the necked down 1.94/1.50 valves and brought them up to 232@.500 and 191@.500, the exhaust went up some by .500 but the intake was down @.550. the ports are so small that they stall and back up by .550 lift. If i remember right .550 lift was 225ish on the intake, nothing drastic but enough to realize a cam over .500 lift is a waste of energy. Comp cams has a 224deg lobe with .502 lift that works really well with these heads. you could do a 224/224 custom grind if you have a fast exhaust port and good exhaust or 224.230 if your exhaust is a little behind the times.
Melting Slicks
Joined: Mar 2004
Posts: 2,141
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From: Pittsburgh Pa
why not.. i am sure you could go to .550 without issue as long as you have the correct springs.. i think vortecs are the only ones with lift issues straight out of the box.
Last edited by pr0zac; Feb 20, 2008 at 06:04 AM.
Burning Brakes
Joined: Aug 2006
Posts: 1,061
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From: Seattle WA
The 113 heads stall flow right about at .500. That means the flow is the same at .500, .600, .700 (if you could get there). A lower-lift valvetrain is easier to build than a higher one, so you'd be spending extra $$ for absolutely no benefit.
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Joined: Dec 1999
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From: Venetia,Pa,USA
I ran my 113s with a max. of 0.570 lift. That's including the 1.6 roller rockers. I used [ per Comp Cam recommendations ] LS1 beehive valve springs. I ran them for two years with NASA racing events. The engine spends most of it's time above 3000 RPM NO PROBLEMS
Since then I purchased AFR Heads. I'll see this March on the Dyno if that was a wise investment. I was hoping for 40 RWHP but everyone says I'll be lucky to get 25. RATS More wasted $$$.
SuperRam
Comp Cam
AFR 195
I'll let everyone know the added HP I get.
Since then I purchased AFR Heads. I'll see this March on the Dyno if that was a wise investment. I was hoping for 40 RWHP but everyone says I'll be lucky to get 25. RATS More wasted $$$.
SuperRam
Comp Cam
AFR 195
I'll let everyone know the added HP I get.
Melting Slicks
Joined: Aug 2003
Posts: 3,395
Likes: 393
From: Lakeville MI
On my 88 113s using LT4 springs/seats/retainers:
Edited my post after I took a look at some old photos that I took. Its tighter than I thought.
I had cut a card to fit between the seal and the retainer to serve as a crude thickness guage, and I had taken a picture of the card thickness with respect to a steel rule. From the picture the card was 9/16" thick.
I only had about 9/16" (0.5625) from the guide to the retainer on the exhaust valves.
For me this was too tight to run the factory intake style seals also on the exhaust valves, since the seal reduced the clearance by about 1/16". The resulting retainer to seal clearance was insufficient for 0.510 lift.
The intake valves had approx 9/16" (0.562) of clearance with the seals in place.
It seems that the guides are machined differently for the intake and exhaust. Something to consider if you wish to run seals on the exhaust.
Just be sure to check your heads with your retainers at install time.
Comp 503 cam with 1.5 rockers (0.503/0.510 lift)
Edited my post after I took a look at some old photos that I took. Its tighter than I thought.
I had cut a card to fit between the seal and the retainer to serve as a crude thickness guage, and I had taken a picture of the card thickness with respect to a steel rule. From the picture the card was 9/16" thick.
I only had about 9/16" (0.5625) from the guide to the retainer on the exhaust valves.
For me this was too tight to run the factory intake style seals also on the exhaust valves, since the seal reduced the clearance by about 1/16". The resulting retainer to seal clearance was insufficient for 0.510 lift.
The intake valves had approx 9/16" (0.562) of clearance with the seals in place.
It seems that the guides are machined differently for the intake and exhaust. Something to consider if you wish to run seals on the exhaust.
Just be sure to check your heads with your retainers at install time.
Comp 503 cam with 1.5 rockers (0.503/0.510 lift)
Last edited by tequilaboy; Feb 20, 2008 at 03:09 PM.
Thread Starter
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Joined: Mar 2006
Posts: 85
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From: Lawrence- Rock Chalk, Jayhawk. KS
"For me this was too tight to run the factory intake style seals also on the exhaust valves, since the seal reduced the clearance by about 1/8". The resulting retainer to seal clearance was insufficient for 0.510 lift"
tequilaboy,
So did you run a different type of seal on the exhaust side?
tequilaboy,
So did you run a different type of seal on the exhaust side?
Last edited by chad89; Feb 20, 2008 at 01:11 PM.
Melting Slicks
Joined: Aug 2003
Posts: 3,395
Likes: 393
From: Lakeville MI
I used larger oil shields from Comp Cams on the exhaust valves to complement the square-ring valve stem seal similar to the factory arrangement.
The oil shields that I used were a lttle big for the springs 1.43" dia. IIRC, but it doesn't seem to be a problem.
The oil shields that I used were a lttle big for the springs 1.43" dia. IIRC, but it doesn't seem to be a problem.
Melting Slicks
Joined: Aug 2003
Posts: 3,395
Likes: 393
From: Lakeville MI
I also used the LT4 seats. I went back and edited my initial post after reviewing some old pics. The clearance was more like 9/16" (0.5625) instead of 5/8".
Last edited by tequilaboy; Feb 20, 2008 at 03:14 PM.
