bronzebb

I finally got my roller cam degreed in after being off a tooth on the timing gear😜 But, I only have 0.085 to 0.090 valve clearance. Should I just run with this, go with a thicker head gasket? I don't want to fly cut the Pistons to get to the recommended 0.100" clearance. Engine is a big block 427. I plan on spinning it to 7k rpm.

Solid LT1

0.090" is OK right at minimum of what I would run. On a hydraulic cam under 7K.....I would soundly sleep at night.

GOSFAST

You'll be safe with .050" intake, .080" exhaust, assuming you don't lose control of the valve train?? Minimum of .135" wall pushrods with lightweight retainers.

Pay close attention to your spring pressure. Generally speaking most of our BBC street/strip solid-roller's see about 260/280 closed and 700 (nominal) open.

Thanks, Gary in N.Y.

P.S. The exhaust is more "critical" than the intake.

bronzebb

It is a solid roller .640 lift 110LSA. Springs are the recommended 953-16. 148 lb closed, 456 lb open.

Can I get a 0.055 gasket?

htown81vette

I had a buddy that used to race Super Gas, and he ran .060" clearance and spun it to 7800 rpms. Big block chevy too! LOL. I know cause I helped him build the engine. He ran that motor for years with no problems (no problems such as P/V clearance issues).

bronzebb

I see felpro has a 0.051 gasket. That would give me 0.012 more clearance. I'd lose 1/10 point of compression.

htown81vette

I wouldn't sweat that 1/10 of a point. You'll never notice the difference, unless your just really running some tightly competitive class in drag racing...

GOSFAST

May not be the best setup for a 7000 RPM 427"??

That closed spring pressure is very close to what we use on the BBC flat-tappet builds.

Looks as though you may be using a cast-core cam? If you have a steel blank you don't have enough spring. We build no mech-roller's using a cast-core blank.

Thanks, Gary in N.Y.

P.S. Also, I know spring numbers aren't always used on the specific mfr, but that 953 isn't recommended for the BBC, at least not in the catalog. It shows as being for a Mopar which uses a 1.5 rocker ratio?

MotorHead

If you have 90 thou on the exhaust I would not sweat it. The specs at 100 thou are there for a very high performance engine that sees 7000RPM all the time and therefore produces a lot of heat. The occasional blip to 7 grand won't do any damage.

bronzebb

It is a steel billet with a cast gear. The springs are what the tech guy at comp cams and the catalog recommend. I told him I wanted to turn 7k. True, I won't be thronging it at 7k rpm in an endurance event but each time I drive the car I have "intentions".😈

So I might want a little more spring or the 0.052" gasket. Thankfully I just measured the push rods but didn't order them yet. I can add 0.015" to each length.

GOSFAST

I'm not trying to argue you down but you must have a cast cam, Comp would only recommend that 953 spring on a cast blank! For a steel blank you need much more pressure? And for 7000 you need steel, it's all that simple.

Head gasket choice is not a major issue?

Thanks, Gary in N.Y.

P.S. If you have the cam part number on the cam card and it ends in a -8 number you have a cast core. If you have cast core you WILL have issues down the road, not maybe, positively, just a matter of time. These cores are fine for retro-hyd rollers, not solid rollers!

bronzebb

So what spring is recommended with this cam? <br >

Jebbysan

Minimum at my shop is .060 intake..... .080 exhaust....
148 is not enough on the seat....456 is not enough over the nose.
What are your springs installed at? (height)
The 953 can be shimmed as it has a lot before bind....you need to remove one and squeeze it on tester to see.....and then check retainer to boss clearance to be sure you have enough room.
I would look at the 954-16....I ran these in Nitrous 1x4 427's with .650 lift.
250/700 closed/open is not necessary at .650 lift.....that would be ideal for .750 +.
Personally....I have never been a huge fan of Comp springs....they do not make their own and they never seem to last in a street application with a lot of lift.
I used a lot of PAC springs......just FYI.
I assume you have a girdle or a shaft system on this?

I hope I have not confused you.....you should check a spring and see where you are really at.

Good luck and have fun.....

Jebby

Jebbysan

There really isn't a spring recommend on this as it is a custom grind.
The three zeros denote that.....
It is a tight lash cam though....so the ramps are not extremely aggressive.
The 953 may work installed at 1.850....like I mentioned....squeeze one and see.....
The old Comp catalogs had pressures for different installed height.
You may want to call them and see if that info is still available.

BTW....that is a nice cam for a 427......you will be happy with it.

Jebby

GOSFAST

That series denotes a steel blank with the Everwear gear (I believe), in my book here it is a hyd-roller deal. You can put mech-rollers on it but the spring it calls for here in the listing is the 933-16 not the 953??

The 933's call for a 170# seat pressure @ 1.950". I believe even this is still too low for anything with a 1.7 rocker??

I also doubt that cam will make any power in the 7000 RPM range?? We use many similar grinds on the "real" retro hyd-roller platform. It's not a bad street cam for that size unit!

Thanks, Gary in N.Y.

P.S. I would try once more to get hold of Comp and see if they can clarify it some. I will stand by my original statement that 140#/150# on a mech-roller is not a real good choice!

bronzebb

Jebby-
I'm not running a shaft system or girdle and the heads are vintage 1967 Al rect port. So I want to keep the spring pressures as low as possible and get the job done but I clearly don't want to break off a stud boss. Right now I'm shimmed in at 1.900. At 473 #/in rate and an 0.030 shim I'd only get around 15# of added pressure at open and closed. I was no where near cool bind minimum when I checked.

So it seems I can run it with a std 0.039 gasket with 0.085 intake valve clearance?

Jebbysan

Yes that would be fine.....I guess all of the valve spring talk is because of the fact that you are somewhat tight P to V.....you need a good spring to control it.....
When I asked about the shaft or girdle I thought it was a small block...then I re-read your OP. Duh moment....

I would go 954....

Good luck

Jebby

Jebbysan

I can feel ya on the want to get it done with as little as possible deal....
The stud bosses on those heads were not the strongest....
Seen a lot of welded units in my time.

Jebby

gkull

Gary knows his valve train builds. My advice is to run light weight tulip valve stem valves like the manley proflow valves and light weight retainers.

That cam is extremely mild for 427 ci. It's the cam i use in my 383 for a daily driver 236/242 SR cam. My first 427 build had the CC xtreme 242/248 and it was so mild that i jump up to a custom lobe around 250 /256

If you want valve control with lighter valves it is still going to take something like 220# closed and around 600# open with your low valve lift

bronzebb

Thanks Gary and Jebby. It seems the consensus is that the 953 springs are a little light. I specifically discussed this with the comp cam tech guy. So I'm a little irritated.

When I got the heads surfaced the machinist was surprised to see there were no weld repairs. I've had them since 1977 but with a stock solid flat cam. I really don't want to break them.