Thinking about some power upgrades - Need some cam advice - Engine Gurus help please

[Chevy305]

Add "LK" to the end of the cam number to get the kit with just lifters.

A block is a block IMO unless you had a bunch of specialty work done to yours. I would have yours rehoned at a minimum.

I looked it up and the cam/lifter kit doesn't save me any money verses buying separately

Why rehone the block? Its still fresh.

 

[nsxxtreme]

I looked it up and the cam/lifter kit doesn't save me any money verses buying separately

Why rehone the block? Its still fresh.

My bad....I thought you were rebuilding and upgrading the entire thing. I didn't read the entire thread my fault

To get a good deal on the kits you have to search a little. You can save money over purchasing them seperately.

Now I see what your doing is just upgrading the top end so what you bought is just fine. I have the Lunati 60120 cam you won't be dissapointed in your cam selection. Do you have a carb or TBI? All I would worry about is the low vaccum at idle with the increased duration.

One thing also to double check is the pushrod length. On mine Edelbrock recommended an additional +.100 of pushrod length if using standard rockers and factory roller pushrod length if using FULL roller rockers. You'd probably have to dig through your Patriot head information to see if they have anything like that.

 

[Chevy305]

My bad....I thought you were rebuilding and upgrading the entire thing. I didn't read the entire thread my fault

To get a good deal on the kits you have to search a little. You can save money over purchasing them seperately.

Now I see what your doing is just upgrading the top end so what you bought is just fine. I have the Lunati 60120 cam you won't be dissapointed in your cam selection. Do you have a carb or TBI? All I would worry about is the low vaccum at idle with the increased duration.

One thing also to double check is the pushrod length. On mine Edelbrock recommended an additional +.100 of pushrod length if using standard rockers and factory roller pushrod length if using FULL roller rockers. You'd probably have to dig through your Patriot head information to see if they have anything like that.

I'm running neither

FAST EZ EFI - its the balls
It self tunes with anything down to 9" of vac at idle. My current cam makes 14" so I know I have room to sacrifice a little idle. What vacuum does your cam make?

As far as the push rod length, I'm going by what Luanti recommends. I'll double check my paperwork; n my heads to be sure though.

 

[nsxxtreme]

I'm running neither

FAST EZ EFI - its the balls
It self tunes with anything down to 9" of vac at idle. My current cam makes 14" so I know I have room to sacrifice a little idle. What vacuum does your cam make?

As far as the push rod length, I'm going by what Luanti recommends. I'll double check my paperwork; n my heads to be sure though.

Be careful what Lunati recomends there techs aren't always qualified to answer those questions and they will admit that if you ask, they will tell you they are not engine builders. My edelbrock etec heads is what required the slightly longer pushrod for standard rockers. So not sure Lunati would know that information anyway.

Mine didn't measure in inches, mine was in kilopascal, which was 50 kilopascal = 14.764991536 inch of mercury [0 °C]. Idle was tricky with the factory ECU. I think in park the vacuum drops to 35. That is about 10 inches of mercury. So your probably going to be right there on the edge. Maybe you will have better luck with the FAST EZ EFI. I was using the factory ECU and a 54MM TBI.

 

[folkenheath]

The only way to know for sure you have the right pushrod length is to check your rocker geometry after you adjust the 1st two rockers. The rocker tips should roll on the center of the valvestem, and they should travel slightly past center both directions through the valve travel. With deck height, valve lengths, seated depth, chamber dimensions, gasket thickness, cam base circle, lifter length, etc, there are too many variables to know for sure. The recommended length may be close enough, but you should always check the rocker geometry when assembling. I have a set of comp pushrod length checkers that I use to measure before I order the pushrods, but starting with the recommendation should work or get you close.

 

[black dawg]

The only way to know for sure you have the right pushrod length is to check your rocker geometry after you adjust the 1st two rockers. The rocker tips should roll on the center of the valvestem, and they should travel slightly past center both directions through the valve travel. With deck height, valve lengths, seated depth, chamber dimensions, gasket thickness, cam base circle, lifter length, etc, there are too many variables to know for sure. The recommended length may be close enough, but you should always check the rocker geometry when assembling. I have a set of comp pushrod length checkers that I use to measure before I order the pushrods, but starting with the recommendation should work or get you close.

How do you check for correct pushrod length accurately with hyd. lifters?

 

[folkenheath]

How do you check for correct pushrod length accurately with hyd. lifters?

The best way is to change the valve springs on one cylinder to some "checking" springs(such as comp cams 4758-2), which are weak enough they don't compress the hydraulic plunger in the lifter. They are only a few dollars. Or you could tighten the rocker until it compresses the plunger all the way and measure how much it compressed, then subtract that length from the checking pushrod once proper geometry is achieved. But make sure you don't start opening the valve before you compress the plunger all the way. Usually the hyd lifters don't actually have that much travel anyway, it may be smaller than the next increment of pushrods.

 

[Chevy305]

Be careful what Lunati recomends there techs aren't always qualified to answer those questions and they will admit that if you ask, they will tell you they are not engine builders. My edelbrock etec heads is what required the slightly longer pushrod for standard rockers. So not sure Lunati would know that information anyway.

Mine didn't measure in inches, mine was in kilopascal, which was 50 kilopascal = 14.764991536 inch of mercury [0 °C]. Idle was tricky with the factory ECU. I think in park the vacuum drops to 35. That is about 10 inches of mercury. So your probably going to be right there on the edge. Maybe you will have better luck with the FAST EZ EFI. I was using the factory ECU and a 54MM TBI.

Why would your vacuum increase in drive? The rpms drop and the IAC opens the throttles slighly to compensate, so if anything vac should drop right? BTW My truck is a stick.

The only way to know for sure you have the right pushrod length is to check your rocker geometry after you adjust the 1st two rockers. The rocker tips should roll on the center of the valvestem, and they should travel slightly past center both directions through the valve travel. With deck height, valve lengths, seated depth, chamber dimensions, gasket thickness, cam base circle, lifter length, etc, there are too many variables to know for sure. The recommended length may be close enough, but you should always check the rocker geometry when assembling. I have a set of comp pushrod length checkers that I use to measure before I order the pushrods, but starting with the recommendation should work or get you close.

Never really thought about all those factors for pushrod length. I just slapped the factory length in when I built this engine and never checked or even knew I needed to check

 

[Chevy305]

Its like Christmas morning!

I'm going to also paralell this swap in my build thread so, don't worry if you start seeing double

So first thing first, I'll be changing the mechanical advance springs today and adjusting the timing according to Heath's advice.

PS: I looked through my paperwork I have on my heads and they recomend 7.900" (+0.100) pushrods for most cases. I'll be sure to check the roller tip to valve stem contact throughout its range of motion to be sure I have the right length pushrods.

PPS: The lifters might say "Lunati" on the bridge but the instructions that came with them said "Installing and Adjusting Your Morel Hydraulic Roller Lifters" You guys were right, Lunati doesn't make the lifters.

 

[nsxxtreme]

Why would your vacuum increase in drive? The rpms drop and the IAC opens the throttles slighly to compensate, so if anything vac should drop right? BTW My truck is a stick.

I may have said it backwards the important part is the vaccum drops and is right on the edge of your fuel injections ability to maintane a decent idle. Mine took a little bit to get right. You might have better luck with the aftermarket unit.

Never really thought about all those factors for pushrod length. I just slapped the factory length in when I built this engine and never checked or even knew I needed to check

Kinda what I thought similiar to my Edelbrocks. For mine if you have FULL roller rockers not just roller tips Edelbrock recommended standard length so you might get lucky and have the same thing.

 

[Chevy305]

So I tried the lighter advance springs and it seems to make the truck a lot more responsive and very quick reving, rather snappy actually
It does have some detonation when in 4th at 1200rpms and pedal to the floor, but thats a situation I would never put the engine in anyways, I don't lug gears like that. I might put the a heavier spring in when I start towing my boat.

For the timing curve. I usually put the lightest springs in they offer. I like the timing to come in fast for more throttle response and more power. It's only too fast if it starts to detonate under load at lower RPM, which could happen easier if you start towing or start in higher gears. If you do any heavy towing you might want to try the medium springs. Or you could use one of each for a 2 stage ramp up. I'd set your timing at 36 deg at 4000 RPM (just make sure the mech timing is all in, with the lightest springs it will be in by 3k RPM) with the vacuum advance disconnected. Then reconnect it and measure the timing of your vacuum advance. You want to try to limit it so that the timing at cruising RPMs with vacuum is about 50 - 52 degrees. You could try 38 WOT degrees as well and see if it runs better without detonation. As always, back off the timing if you are getting detonation. Down low = heavier springs, at WOT = turn dizzy, and reajust the vacuum can to put it back at 50 - 52 for cruise.

There's still some more work to be done with the timing though. I couldn't get it dialed in perfect but it is improved. I don't know why but the engine can take a lot of timing without detonating
So right now the timing sits at 38* total without the vac hooked up. However this gives it a base timing at 18* which seems way too much. And With the vac hooked up around cruise rpm its around 56-60* which sounds like too much to me but I couldn't get at the little adjustment screw because my valve covers are in the way. So I'd have to pull the distributor to adjust it and I didn't feel like it when I'm about to tear the engine down soon anyway. The truck runs good and strong at where it is so I'm going to leave it as is until I get the new cam in.

 

[folkenheath]

So I tried the lighter advance springs and it seems to make the truck a lot more responsive and very quick reving, rather snappy actually
It does have some detonation when in 4th at 1200rpms and pedal to the floor, but thats a situation I would never put the engine in anyways, I don't lug gears like that. I might put the a heavier spring in when I start towing my boat.



There's still some more work to be done with the timing though. I couldn't get it dialed in perfect but it is improved. I don't know why but the engine can take a lot of timing without detonating
So right now the timing sits at 38* total without the vac hooked up. However this gives it a base timing at 18* which seems way too much. And With the vac hooked up around cruise rpm its around 56-60* which sounds like too much to me but I couldn't get at the little adjustment screw because my valve covers are in the way. So I'd have to pull the distributor to adjust it and I didn't feel like it when I'm about to tear the engine down soon anyway. The truck runs good and strong at where it is so I'm going to leave it as is until I get the new cam in.

Sounds good to me, nothing wrong with a base timing of 18 degrees, plenty retarded for starting and it should run better. I was running a base timing of about 24 degrees for a while on my big block, never heard any detonation but I did get a little dieseling a couple times on shutdown when the idle was high back with my carb when the choke was still on, so I backed it off a little under 20. I actually have the timing in my 388 in my regal locked solid at 38 degrees, I removed the vacuum can and mechanical advance and tack welded it. Never moves. I did use the 20 start retard feature of the digital 6+ box, but ran it for a couple years locked at 38 even for starting. If you hook the vacuum advance up to full vacuum at idle at will probably idle even better with more vacuum, and with the new larger cam that will more than likely help.

 

[nsxxtreme]

There's still some more work to be done with the timing though. I couldn't get it dialed in perfect but it is improved. I don't know why but the engine can take a lot of timing without detonating
So right now the timing sits at 38* total without the vac hooked up. However this gives it a base timing at 18* which seems way too much. And With the vac hooked up around cruise rpm its around 56-60* which sounds like too much to me but I couldn't get at the little adjustment screw because my valve covers are in the way. So I'd have to pull the distributor to adjust it and I didn't feel like it when I'm about to tear the engine down soon anyway. The truck runs good and strong at where it is so I'm going to leave it as is until I get the new cam in.

My Lunati cam likes lots of timing. I think I am running 6 degrees of base timing. Hard to start with 0 degrees base timing. That goes back to what I was saying about producing enough vaccum at idle. So your lunati cam will probably like timing just like your current cam.

There is one thing I would also watch once you get things back together. Watch your oil pressure closely. Those lunati "morel" lifters seem to use a lot of oil. Do you have a standard or HV oil pump? I know a lot of guys like to run standard volume high pressure pumps. This might be a case you dont want to do that. I don't want to debate which is correct I will just say keep an eye out on your oil pressure. Expecially at high rpm (4500 +).

 

[80' 427]

Most of my hot engines have very limited advance or ar locked out. They usually start, idle, and run the best that way. They have a little bit of a hard start but I have never had one not start.

 

[Chevy305]

There is one thing I would also watch once you get things back together. Watch your oil pressure closely. Those lunati "morel" lifters seem to use a lot of oil. Do you have a standard or HV oil pump? I know a lot of guys like to run standard volume high pressure pumps. This might be a case you dont want to do that. I don't want to debate which is correct I will just say keep an eye out on your oil pressure. Expecially at high rpm (4500 +).

I am running a Milodon standard volume, high pressure pump. Are you saying my oil pressure will start to dip at high rpm? So if the lifters like their oil, then I should be running a high volume pump?


Also the FAST instructions specifically state not to hook the distributor vacuum advance to the full manifold port on the throttle body. I did try it when I ran a carb and it didn't make a difference how the engine ran.

 

[folkenheath]

My fast instructions never said anything about hooking the distributor up one way or another, it just points out which vacuum port is ported. However, even if it did say not to, thats because of emissions. I would of still hooked it up to the full manifold vacuum, as I did, and have been running it that way the whole time. I have never changed the vacuum from full to ported and not had it make a difference of the idle. It always idles higher and smoother and sometimes with more vacuum even after I drop the idle back down. And it usually holds its RPM more consistent when I would change it from drive to neutral and vice versa. That is not as much of an issue with EFI and an IAC valve though. It will only make a difference at idle, obviously everywhere else it is still the same. So if it idles the way you want either method, then I guess thats good enough.

 

[80' 427]

If your truck detonates in 4th you may just try one light spring and one med springs. It will then kinda split the difference on the curves. Also as your dist gets gummy I find that the light ones don't like to pull the weights in and you get a funky idle so I use one light and one med. Just a thought. The only dist I have that has vac advance has a 10 deg can so it is minimized.

 

[Chevy305]

If your truck detonates in 4th you may just try one light spring and one med springs. It will then kinda split the difference on the curves. Also as your dist gets gummy I find that the light ones don't like to pull the weights in and you get a funky idle so I use one light and one med. Just a thought. The only dist I have that has vac advance has a 10 deg can so it is minimized.

I'll see how it acts with the new cam that I am now in the process of installing

 

[Chevy305]

So I have the new cam in and I have a few questions about setting up the cam endplay. I followed your guide here your posted earlier in the thread:

Also, isn't your block new enough you can use the roller spiders and slab side lifters? Lifters may be cheaper if they aren't the retro fit style. Don't forget, with a roller cam you need a cam button to set camshaft endplay, and preferably a torrington bearing behind the timing chain, although not required. Roller cams have a flat parallel lobe surface and don't have any means to hold themselves in position axially, and if they float around in the block it can cause erratic timing, or worst case, catastrophic failure if a lifter body contacts an adjacent lobe or the chain hits the cover. So make sure to at least use a cam button and set camshaft endplay by bending the timing chain cover in that spot if you have to. Don't forget to include the gasket dry when you measure. I usually set it at the high side with the gasket in and snug (.009"), and when I install the timing cover and tighten it down properly I am at the low end of the endplay tolerance, your results may vary. I measure endplay with a caliper, I just pick a spot in the lifter valley where I can consistently measure from the block to one of the lobes sticking up, and then move the cam back and forth while I measure.

I had to dent out the timing cover To gain some play. But when I push the cam back and forwarth I can see the timing cover deflect. Is this going to ruin my measurements? Right now I'm at .008" including the deflection seen in the timing cover with the bolts torqued. Should I change it or keep it?

 

[folkenheath]

You should be fine, I have been running the stamped cover for years without issues. As long as you can feel some backlash before it deflects that sounds good to me, you just don't want it too tight without the deflection. I think the minimum is .004" if I remember correctly. I had to dent them too. Can you see what it is without the deflection? I really don't think it's going to deflect much because there really isn't much force at all pushing it forward. If you look at the cam the only thing that can put any force front/back is the distributor gear, and since the cam rotates clockwise (looking from the front of the engine) that will force the cam back against the block, not forward. So the amount of force pushing forward into the timing cover is going to be either close to zero or it won't even be touching it.

Edit: Are you talking about deflection when you tighten it down? Or deflection when you are moving the cam? Try to move the cam very lightyl without deflecting the cover, and make sure it has at least a few thousandths and your are fine. I just looked up the spec, .004 - .010".

Here is a pdf from comp cams about it...

http://www.compcams.com/catalog/COMP2011/pdf/COMP_Catalog_2011_408.pdf

I have been running the stamped covers in both small and big blocks, the small block for 15 years, no issues. I just dented the cover, back when I put that in there was no recommendations for shimming or anything, they just told you to dent the covers. My timing is very consistent.