Howards Camshafts (Summit)

I'd like to point out that cam manufacturer's descriptions of their camshaft's characteristics are notoriously inaccurate. This post of yours is from another topic:

quote:

Originally posted by Horace Cope:

... I have new Trickflow CNC heads fitted on my Pantera mated to a Holley Street Dominator manifold.

However I am a bit disappointed in the performance especially low down. Would you recommend the TFS track heat manifold and if not whats a good intake match.

Cam is Comp Hyd Roller .578 lift plus Holley Vac sec

Had this setup with my Aussie 2v quench heads and performance was impressive

Horace

The current camshaft is 290°/290°, 110° LSA, 70° overlap. That's a big cam to choose for somebody looking for performance "down low". Since you liked the performance of the engine with the Aussie 302C heads, the swap to Trick Flow heads and the choice of the big cam lead me to believe you're looking for higher output from your Pantera's engine, would that be accurate?

When you changed the heads, did you change any other parts simultaneously, or just the heads? By the way, which Holley carburetor did you purchase and install? Does the short block have dished pistons or flat tops?

Rather than comment on the quality of the Howard cam, if you don't mind I'd like to understand what performance and power band characteristics you are attempting to achieve. Could you also share with us what troubleshooting you have performed to the current set-up, if at all, in trying to understand why it doesn't perform to your satisfaction?

Hi George

Happy to answer your questions: I didn't make it clear that my old Aussie 2V setup I mention was on another Pantera I once owned. I wanted to try and replicate that.

This engine was in the car when bought, stock motor with 4V open chamber heads etc. Not a lot could be salvaged so it was stripped and totally rebuilt. Good thing was it was a 4 bolt main. Pistons were changed to +30 forged flat tops, TFS complete heads with 1.55 springs and 62cc chambers, Comp cam roller hyd kit as you mention. Harland Sharp roller rockers. Holley 600 vac sec with 70 primaries and secondary fuel block 72 secondaries. Following previous advice from you lifter galleries were bored and sleeved.

Only thing kept from the old engine was the Holley Street Dominator intake manifold and crank.

Performance of this engine is pretty impressive but the power band comes in much too late for me. Would like it to come in a lot earlier

My thinking is most of the setup is good but I may have gone for the wrong cam hence looking at a different spec cam. I am also not convinced by the single plane intake. The old Aussie 2V heads were mated with an Edelbrock performer 2v dual plane.

In summary: Current performance good but not good enough. Need the power band lower down.

Cheers

The video gives a good comparison between single plane and dual plane manifold performance. This helped me decide what was best for me on my car. Here is a direct link to the video below. Edelbrock Intake Manifold Dyno Test

Mike I am in full agreement regarding swapping the Holley manifold for the Performer 2V intake manifold.

For your application I am strongly opposed to any dual plane manifold with a cut down plenum divider, or a dual plane manifold used in conjunction with an open spacer below the carburetor. This is due to your expressed desire for improved low rpm performance. Like a single plane manifold those things negate the purpose of having "dual planes" in the first place ... i.e. extending the time between pulses within the intake manifold.

I also believe you need to reduce overlap. Since your Pantera's engine is already set-up for a hydraulic roller cam, I'd suggest swapping the Comp Cams camshaft for the smallest Crane Cams hydraulic roller (HR216). The only thing besides the cam that "may" need to be swapped is the distributor gear. The Crane camshaft is ground on a steel core and needs a steel distributor gear for compatibility.

quote:

Originally posted by Horace Cope:
Anybody used these Howards camshafts from Summit and can shed some light on their quality etc.

Have to admit I have not heard of them.

I have a Comp Cam roller hydraulic at present which I wish to change out, not giving the performance expected.

The spec and performance I am looking for seems to be provided by a Howard cam.

Cheers

Call up Bullet Cams, they are very nice, they could design one to your requirements.

Thanks for the info George and others, Edelbrock performer ordered and is on its way. No spacers or plenum dividers planned.

Another problem seems to have reared its head this last weekend. Car ticks over and is fine till about 2000 revs. After 2000 revs and up a loud tapping noise appears. Back off again below 2000 and it goes away again.

Sounds to me like the lifters maybe getting starved of oil somehow.

I am running Comp cam roller hyd, comp cam roller lifters, std oil pump, 10 qrt pan, lifter bores have been sleeved. 10w 40 semi synthetic oil.

I also run a capilliary oil guage. One thing that has been worrying me since the rebuild is that max oil pressure is never more than 50psi and less once oil is hot. Oil pump is new, do you think it could be faulty, new ARP oil pump drive fitted.

Any ideas George or anyone as to whats going on here.

Cheers

Horace, Have you done any of the oil system mods recommended? George Pence has a great tutorial about this.

I'm sorry you are having problems with the engine.

Tappet noise, noise in the valve train, etc. is usually the result of insufficient valve guide clearance. Other valve train noise can be caused by a faulty tappet having an excessive bleed-down rate, or a tappet that has come apart (the tappet internals have popped-out).

However, if the tapping you hear is not coming from the valve train, its usually a spun rod bearing. A spun rod bearing may contribute to low oil pressure as well.

On the subject of oil pressure, there is normally plenty of oil pressure with tappet bore bushings. Its hard to guess why it may be low, if its not related to a spun bearing. Since the pump has a "built-in" relief valve it is as likely a culprit as anything else. I always recommend disassembly of new pumps, cleaning them and inspecting them before installing them. Finding metal chips is common. A metal chip lodged into the relief valve, holding it partially open, is another possible cause of low oil pressure.

I suspect the roller rockers are tapping the inside of the valve cover.

JT that was the first thing I checked, no evidence or marks on either the rockers or the inside of the valve covers.

As mentioned the lifter bores were sleeved which is one of George's recommendations.

Lifter clearances (pre loads) were done in accordance with the manuals at the build stage, ie 3/4 turn etc. Roller hyd lifters.

If it was a spun bearing George why would it only happen above a certain revs, surely we would hear it from the start. Because its only happening over 2000 thats whats pointing me towards oil and pressure or lack of it etc.

Will have to pull the engine to look at possibly cleaning the oil pump. Thats the time to check the rod bearings also as you suggest.
Oh well another weekends work and another couple of hundred $s on gaskets coming up.

cheers

I have no experience with the Comp Cams hydraulic roller tappets, I don't know who makes them. I don't know how much compression Comp Cams suggests for adjustment. But 3/4 turns compression sounds like too much. 3/4 turn was fine 4 decades ago, but the plungers of modern hydraulic tappets are not capable of being compressed as much as they were 4 decades ago ... nor do they need to be compressed as much. Start with re-adjusting the tappets, in the car, with the engine warmed-up and running. Adjust them 1/4 turn beyond the point where they become silent.

Were the bearings recently replaced, or are they the old bearings? If they are the old bearings, they are worn, that would explain the low oil pressure.

George/guys

Pulled the engine today and the noisy tappet turned out to be a completely wiped out crank journal, see pictures below.

No 3 rod journal has been worn down completely, possibly in excess of 30 thou, not sure if this crank is saveable. However No 7 next to it is fine as is the other 6. Oil pressure was not great but never below 50 psi.

This was a brand new engine build, everything new, rods, bearings, ARP rod bolts,fresh oil, new HV oil pump, ARP main studs etc etc. Lifter bores sleeved, crank checked cleaned and passed by the engineering shop.

This engine has not done more than 20 miles since being built. Why would something as extreme as this happen in such a short time.

Main bearings are all good as is the other 7 rod bearings. Nothing left of No 3 rod bearing most of which is shrapnel in the sump.

Needing to take this back to the machine shop but any ideas ?? Got me absolutely stumped.

Cheers

More pics

and more

Mike,

Was the engine hard to turnover to start initially? The only suggestion I can come up with is the rod & cap were clamping the bearing on the journal and not clearance fitted. Might be an issue with one rod if these were new, have you checked dimensions?

Julian

Julian

No quite the opposite, it was quite free even turning over by hand.

Yes they were all new ARP rod bolts. Fitted by the engineering shop who assured me they were sized ????

For that much wear in such a short space of time its obviously seen very little oil but why. All the other rods and rod bearings are good ?

Mike

I'm quite sorry this happened.

Assuming all of the connecting rod big ends were properly resized after the rod bolts had been replaced, I would guess that the cap for that connecting rod was installed in the wrong orientation.

wow i had the same thing same journal on my first Cleveland, to this day I'm not sure what the cause was but it could've been i flipped a rod cap backwards

http://pantera.infopop.cc/eve/...0045562/m/5601027956

4V and proud

that link you refer to on the forum was a friends engine we were putting together not mine, totally different engine though the ARP rod bolts were fitted by the same machine shop.

The tightness in turning ended up being the crank journals not being machined out to the radius correctly. Funnily enough done by the owner at a previous machine shop.

Thanks George, Possibility I could have put a cap on backwards in the build assembly but we will never know now. Usually something I'm methodical on but we can all make mistakes, it could be something as simple as that.

All the parts will be back down at the machine shop today. I will update on their comments