newbie2vette

While adjusting the lifters on a 79, I discovered #8 cylinder intake lifter retaining ring worked itself lose. what kind of damage can expect? Is it ideal to replace the cam and lifters together or just lifters?

What kind of cam would be idea to upgrade from stock (L48)?

NeverTooOld

The retaining ring's only purpose is to keep the plunger from popping out before the lifter gets installed into an engine. And the Competition Cams 268H is an excellent cam for low compression engines; often making close to one horsepower per cubic inch of displacement.

REELAV8R

I seem to recall that a lifter retainer coming out can be a symptom of lifter pump.
Meaning your valve springs are weak, or your pre-load is incorrect or you reved it to high too long.

For a new cam I believe the 268H would be far to much duration for a stock L-48 compression ratio. The L-48 runs about 7.7:1 true CR vs the advertised 8.5:1.

Take a look at the 268H dyno. 342HP and this is with a 9.25:1 CR and Dart SR heads not the GM 882's you probably have on that L-48. You'll see that you will not likely make anywhere near 1HP per CI with your L-48. Not to mention it will be a dog anywhere below probably 2500-3000 RPM maybe even higher than that.
http://www.compcams.com/v002/Pages/388/XE268H-10.aspx

Duration wise you would be looking at maybe 256 degrees advertised on a 110 to a 112 LSA for your L-48 without changing anything else.

Better would be something like this

http://www.lunatipower.com/Product.aspx?id=1981&gid=287

Or this

http://www.lunatipower.com/Product.aspx?id=1982&gid=287

Low CR really limits the choices available to you in a cam in order to get decent bottom end torque with the low CR of the engine.
A higher stall torque converter (2500 or so) or 3.55 or shorter gears would help a lot. The 3.08 gearing is not a power/torque producing rear end with the L-48 in stock form.

427Hotrod

My biggest worry is did you find the clip? They have a nasty habit of getting into the oil pump and locking things up.

JIM

HeadsU.P.

How is that possible? Wouldn't the pickup screen detain it?

NewbVetteGuy

Good advice.

If your block surface is nice and flat you could also replace the head gasket with the Felpro 0.015" ultra-thin gasket (cover it with copper seal per the instructions) and gain +0.5 CR and then still go with one of those two cams and a higher stall TC.


The higher static and dynamic compression might even net you a fuel economy gain.


Adam

newbie2vette

Thank you everyone for the great inputs. The retaining ring was sitting next to the cavity, extracted it with a magnet.
I went the cam and lifter kit below; from my understanding this should not promote any major change to the converter and the diff and would yield good low to mid range tq and power.

COMP Cams Xtreme Energy 262H Hydraulic Flat Tappet Camshaft & Lifter Kit Lift: .462" /.469" Duration: 262°/270° RPM Range: 1300-5600
Xtreme Energy 262H Hydraulic Flat Tappet Camshaft & Lifter Kit
Lift: .462''/.469''
Duration: 262°/270°
RPM Range: 1300-5600

427Hotrod

The stock type lifters have a small wire clip....thinner wire than a paperclip. It will get through the screen. Seen it several times.

I never run those type lifters...only use the ones with a real c-clip.

JIM

HeadsU.P.

Thanks for the info. I knew there was a reason I put a strong magnet on the oil pan.

REELAV8R

When I took my bone stock 77 L-48 heads off, the gasket in use was a .017 shim gasket. So going to a .015 shim gasket will net you no gain on the CR.

HeadsU.P.

I think you mean a CR gain of 0.000000005 with that gasket.

derekderek

approximately...

CanadaGrant

I was really surprised to see that even Comp was using paper clips in their stuff not only today, but going back years ago. A miss-adjustment or loose adjustment in your valve train can cost you your engine as those retainers don't really retain much and come out in pieces...

427Hotrod

Comp sources from many folks. They will use stock type stuff on mild cams. But good ones are available.

JIM