Max flat tappet lift possible w/o zinc concerns?

[qdeezie]

I'm referencing a small block Ford engine here. I am going to rebuild this engine and I was dead set on upgrading to a roller camshaft, nothing performance oriented, but because it's simply a feasible upgrade with perks. However, I've found a flat tappet camshaft that's a little bit above stock, but has more lift than the stock cam and I actually like the specs, plus I will still have a smooth idle.

My question is how much lift on a flat tappet cam warrants concerns about the "lower" amounts of zinc in today's oils? My goal here is to not have to buy additives or any sort of specialized high zinc motor oil. I want to use the same regular off the shelf synthetic motor oils that I have always been using. I'm able to do this with the stock flat tappet engine I have right now and I don't want to change from this off the shelf philosophy.

If it helps, these are the specs I'm looking at on that flat tappet camshaft:

.424" Intake Valve Lift
.448" Exhaust Valve Lift
.265" Intake Cam Lift
.280" Exhaust Cam Lift
270 Degree Intake Duration
280 Degree Exhaust Duration

Thoughts?

 

[xxch4osxx]

A good HDEO would take care of your concerns about ZDDP content. Rotella T5 10w30 would be a good choice.

 

[229]

I did this and lost a motor. I would do the roller cam conversion with the spider hold-downs for the lifters if you insist on the "off the shelf philosophy". You can get similar cam specs with a roller. Diesel oil will be made more emissions system friendly as time passes. If you insist on the flat tappet cam at least spend the extra hun and get it nitrided hardened and use break-in oil to have any hope of it surviving. Don't make the mistake I made. Sure, I was reimbursed for the cam but lost my newly rebuilt Ford engine.

 

[MrBeachcomber]

It's really not a question of lift, but more how aggressive is the cam's lobe profile and what spring pressures are recommended for the cam by the manufacturer. (Aggressive opening, high-lift cams with higher than stock spring pressures seem to need the ZDDP more than the stock, run-of-the-mill flat tappet cams.) IMHO, given the lift/duration data you've provided for the cam, this cam doesn't sound radical enough to warrant ZDDP additives after break-in.

 

[The_Eric]

Originally Posted By: MrBeachcomber
It's really not a question of lift, but more how aggressive is the cam's lobe profile and what spring pressures are recommended for the cam by the manufacturer. (Aggressive opening, high-lift cams with higher than stock spring pressures seem to need the ZDDP more than the stock, run-of-the-mill flat tappet cams.) IMHO, given the lift/duration data you've provided for the cam, this cam doesn't sound radical enough to warrant ZDDP additives after break-in.


Well put.

I'd say if your cam requires springs in the neighborhood of ~280+lbs over the nose and/or 130lbs on the seat, you'll need to run an HDEO at the minimum and a purpose blended break in oil.

 

[qdeezie]

Originally Posted By: The_Eric
Originally Posted By: MrBeachcomber
It's really not a question of lift, but more how aggressive is the cam's lobe profile and what spring pressures are recommended for the cam by the manufacturer. (Aggressive opening, high-lift cams with higher than stock spring pressures seem to need the ZDDP more than the stock, run-of-the-mill flat tappet cams.) IMHO, given the lift/duration data you've provided for the cam, this cam doesn't sound radical enough to warrant ZDDP additives after break-in.


Well put.

I'd say if your cam requires springs in the neighborhood of ~280+lbs over the nose and/or 130lbs on the seat, you'll need to run an HDEO at the minimum and a purpose blended break in oil.



I'd be going with new replacement stock valve springs. Nothing exotic or upgraded in any way other than minor upgrade to the camshaft.

 

[The_Eric]

As long as the cam doesn't need more pressure (most cam cards will give a recommended spring) , you'll be fine with a purpose blended cam break in oil and PCMO or a HDEO from there on out.

 

[qdeezie]

Originally Posted By: 229
I did this and lost a motor. I would do the roller cam conversion with the spider hold-downs for the lifters if you insist on the "off the shelf philosophy". You can get similar cam specs with a roller. Diesel oil will be made more emissions system friendly as time passes. If you insist on the flat tappet cam at least spend the extra hun and get it nitrided hardened and use break-in oil to have any hope of it surviving. Don't make the mistake I made. Sure, I was reimbursed for the cam but lost my newly rebuilt Ford engine.


Would you mind sharing the specs on the cam and valve springs? Were the valve springs performance springs or stock? I'm not dead set on flat tappet and really the idea of sticking with flat just hit me recently. I started purchasing stuff to convert to roller, but I'm entertaining the idea of keeping it flat.

 

[A_Harman]

Go roller. You can get much more valve lift with a given effective duration with a roller cam and you side-step any concern over flat tappet wear since you don't want to use a high-zinc oil.

 

[TFB1]

A 1990 5.0 should be easy to convert to factory roller, as these blocks usually have the required taller lifter bores... Possibly the spider hold down bolt holes will not have been tapped at the factory... Parts necessary are the cam, lifters, lifter retainers, spider, push rods and a steel drive gear for the distributor... Biggest problem is all factory roller cams are for the 13726548 firing order where as your truck 5.0 fires 15426378... I'm not sure if a cam is available that uses factory parts for your firing order...

BTW Unless it idles at least 18" of vacuum, a "warmer cam" will cause all sorts of drivibility issues on a speed densety system...

 

[qdeezie]

Originally Posted By: TFB1
A 1990 5.0 should be easy to convert to factory roller, as these blocks usually have the required taller lifter bores... Possibly the spider hold down bolt holes will not have been tapped at the factory... Parts necessary are the cam, lifters, lifter retainers, spider, push rods and a steel drive gear for the distributor... Biggest problem is all factory roller cams are for the 13726548 firing order where as your truck 5.0 fires 15426378... I'm not sure if a cam is available that uses factory parts for your firing order...

BTW Unless it idles at least 18" of vacuum, a "warmer cam" will cause all sorts of drivibility issues on a speed densety system...


It's interesting you mention the firing order because that is something that's very important with what cam I decide to go with. I already have the 5.0 Explorer roller cam which has the 13726548 firing order but I'm somewhat hesitant to use it specifically because of the firing order.

The 92-93 F150 engines (and I think the non-HO 86 to 91 car 5.0 cams) have roller cams with the 15426378 order. I believe the specs on this camshaft are the same as the specs for the current flat tappet camshaft that I have now, which I am perfectly ok with.

I'm wanting to keep the 15426378 firing order for the sole reason of ensuring that things match from a wiring perspective to keep confusion out of the way. Also, the emissions label under the hood indicates the 15426378 firing order, which I actually use as a reference myself whenever I pull spark plug wires. Also, when I replaced the intake manifold gasket, I found that the 2 spider bolt hold down locations were pre-tapped from the factory.

I guess I'm leaning back towards roller. I need to find a deal on a non-HO roller camshaft. It doesn't make much since to spend big dollars on a stock roller camshaft on such a mass produced engine. I'd even spring for a used non-HO roller camshaft as long as it's not worn.

 

[TFB1]

I had a moment of brain freeze, you are correct the '86-'91 5.0 in full size Ford, Merc & Lincolns('86-'90) used a roller cam with the 15426378 firing order... Also the '86-'88 T-Bird & Cougar used these same roller non-HO 5.0 engines...

That's good news on the spider hold down, I had a 85.5 F-150 block that had the tall roller lifter bosses but was not tapped... Of course it was originally a non roller motor...

If you can get the parts reasonable it's worth the swap, internal friction is reduced enough to make a slight increase in fuel economy...

 

[229]

Stock

Originally Posted By: qdeezie
Originally Posted By: 229
I did this and lost a motor. I would do the roller cam conversion with the spider hold-downs for the lifters if you insist on the "off the shelf philosophy". You can get similar cam specs with a roller. Diesel oil will be made more emissions system friendly as time passes. If you insist on the flat tappet cam at least spend the extra hun and get it nitrided hardened and use break-in oil to have any hope of it surviving. Don't make the mistake I made. Sure, I was reimbursed for the cam but lost my newly rebuilt Ford engine.


Would you mind sharing the specs on the cam and valve springs? Were the valve springs performance springs or stock? I'm not dead set on flat tappet and really the idea of sticking with flat just hit me recently. I started purchasing stuff to convert to roller, but I'm entertaining the idea of keeping it flat.

 

[qdeezie]

I just found a '92 Non-HO 5.0L engine that runs good that I'm going to pick up. So it's official I'm going with a roller camshaft. What great timing and I get to save some major dollars in the process.

And my list in possible oil choices just expanded, but I'll probably stick with Xw-30/Xw-40.

 

[The_Eric]

I wouldn't worry about having to switch firing orders.. I've done it with no ill effects. The only consideration is if you have some sort of computer control that might freak out at the change.