Chevy & GMC Vans

The time has come to do an upgrade as my flat tappet cam has worn out on my 350 in my van. I have a set of L31 heads & a roller cam set up to install onto my L05 engine. Tomorrow (Mar 25th) after work I begin the disassembly/tear down. I will try to keep the pics posted as I go showing the upgrade as it occurs.

What cam are you planninng to use? I've heard good things about the Hot Cam kit for the LT1 I think, but I don't really know much more about it than that.

Are going to replace the timing chain and sprockets???.What do you have in there now,are they stock units??.I read that GM machines in their's a 2 degree retard for emissions.I think it was in www.enginebuilder.com Maybe it would with the heads off a good time to degree in the cam and pick up some free torque/hp.Just a thought.I tried to bring up the spec's with this old rag of a computer and couldn't.Looking forward to your build.

Woke up this am with a cold, took some meds & hope it does not get worse. [-o<
The end of the work day arrived & it was time to teardown the engine in my van & get this project in gear.

5:00, bring the van in & set it up on the hoist. Snapped a quick pic.

6:00, snapped another quick pic to show the progress.....

8:00, I am done for the day & feeling worse for wear as I forgot to take more meds to keep ahead of the cold symptoms. Pleased with the progress that I was able to make in spite of feeling sick.

Found exactly what I expected to see...a worn out cam. The 2nd lobe (intake of # 2 cylinder) is quite worn out.

Made it home & gonna rest up for tomorrow. May have a helping hand tomorrow from Sanja (Reaper)

6spd_monte wrote:What cam are you planninng to use? I've heard good things about the Hot Cam kit for the LT1 I think, but I don't really know much more about it than that.

Measured with a 1.5 rocker, the Hot Cam has a valve lift of .525 intake & .525 exhaust.
The reground cam that I will be using will have a valve lift of .450 intake & .459 exhaust.
Originally when the cam was in a '98 pickup, it had a lift of .417 intake & .417 exhaust.

Now I know why you were sniffling on the phone tonight.
I'll be there around 9 am tomorrow.

1Gary wrote:Are going to replace the timing chain and sprockets???.What do you have in there now,are they stock units??.I read that GM machines in their's a 2 degree retard for emissions.I think it was in http://www.enginebuilder.com Maybe it would with the heads off a good time to degree in the cam and pick up some free torque/hp.Just a thought.I tried to bring up the spec's with this old rag of a computer and couldn't.Looking forward to your build.

I will be putting in a single roller - recommended for roller cam set ups. Similar to this one...

I had a double roller chain set up in there previously.

James-got the button for the front of the roller cam??.Hoist??.You doing this at work??.Man I am jealous.That sure makes jobs easier bring it up to a comfortable working level.

WOW.....you've been a busy boy. Hope you get to feeling better soon.

Nice...and liking the pics, helps me understand exactly what it is you are doing

It shouldn't need a cam button Gary, only retro rollers do. Even if you use OEM lifters and retainers with a retro roller the lock plate won't fit because the cam has a notch cut into it for it. Since this is a factory block there's a lock plate between the cam and the sprocket. What duration is the cam you got James? That's more important than the lift in most cases, then again if the old cam was the stock one and it wasn't toast it was still seriously impeding power. Even going to a cam like the stock "good" TPI or the LT1 cam should be good for 25hp minimal. Emissions cams suck!

Mr_Roboto wrote:It shouldn't need a cam button Gary, only retro rollers do. Even if you use OEM lifters and retainers with a retro roller the lock plate won't fit because the cam has a notch cut into it for it. Since this is a factory block there's a lock plate between the cam and the sprocket. What duration is the cam you got James? That's more important than the lift in most cases, then again if the old cam was the stock one and it wasn't toast it was still seriously impeding power. Even going to a cam like the stock "good" TPI or the LT1 cam should be good for 25hp minimal. Emissions cams suck!

Thanks for the info Alex.Thought because of the roller springs all of them used a button because of the cam wanting to walk.You know.Now that you said that,I kind of do remember a retainer plate on my 1995 L31 for Ole Yellar.Be so long ago since I took it apart.I'll have to look in the parts baggies when I go back to the shop tomorrow.I do know Com cams came up with a upgraded lifter retainer where you can get afew more RPM's with them.O.E.M. is limited.I think O.E.M. was 5250 and Com's was 6200.Wonder if he is going to have to change exhaust manifolds with the head change??.I wouldn't think so.

Honestly I'm a fan of this style retainers. Beats the "dog bones" that they used to use because you just spin the cam twice and you can yank it out. Don't even need to remove the intake.

https://www.citycratemotors.com/scripts ... uct=323925

PN is 88958652 which I thought I put in the thread already.

wouldn't that make upgrading your cam really easy? do you know anyone who's used that.

v8famvan: i'm with zam pictures are worth a thousand words and also gives me an idea what to look forward too

Supposedly all the LSX engines in the recent past have this setup. I'm thinking about trying to retro fit it into a non roller block using 3.1L lifters so I don't have to buy those retro rollers. Frickin things are expensive if I do I'm going solid that's for certain!

The big reason that rollers require a retainer is that the lobes are ground perfectly straight. If you look at a flat tappet cam you will notice the lobes are ground at an angle. The reasons for this are two fold it causes the cam to stay in place but it also causes the lifter to rotate as well. This is one of the reasons why the lifter bore centering of an engine is actually critical with a flat tappet cam. The Buick 3.8Ls have the #3 exhaust lobe turning the opposite of the others because the bore is in the wrong location. It's also known for eating them anyways.