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fantastic new cam design !!!!

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trfourtune

Jedi Knight
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FYI to all,
A little background first about Tilden Technologies LLC. They make the race cams that many of the triumph tr4 racers use because they make the most and best power possible in north american vintage racing. The late Jack drews, and Tony Drews run Tilden's cams and others. Specifically designed lobes for the tractor engine, not chev lobe design (which some "triumph" cams are). These are "clean sheet" cams, not copies.

Tilden Technologies LLC have just finished the design of a brand new street cam for triumph tr3's and tr4's. This is going to prove to be an absolutely fantastic cam. It's 270 degrees duration (which is not a lot) but the lift on this cam is better than a lot of 290 degree cams and equal to many 300 degree cams. It is specifically designed for the triumph lifter which is .937" diameter. Many triumph cams are not specifically designed for this lifter and give up a lot of the potential that a large diameter lifter can permit.
this cam will work from low rpms all the way through to 6000.

I am so convinced that this is going to be the best hot street cam that i just ordered mine and sent 3 cores to them. I am building a 10:1 motor with long rods, dual side drafts etc.

I have no financial interest in Tilden at all. I would like to promote a good thing when i see it though. check out the site.
https://www.tildentechnologies.com/index.html

Rob
 
FWIW, I also have an order in for one of Larry's 270 cams. But since the reground cams are slightly weaker (the diameter of the front part of the shaft gets reduced slightly to produce enough lift); I opted for his grind on a new blank. The cost is nearly double, but still cheap compared to breaking a cam.
 
Randall,
I bought a new one also, but sent him cores so he can have some in stock. Also, don't let the fairly low duration fool you, this is going to be a fantastic cam.
Given that this is a street cam, i think a regrind will be fine unless you are ALWAYS revving the snot out of your motor.I plan to hit the track occationally and do some auto-x'ing.
Rob
 
trfourtune said:
FYI to all,
A little background first about Tilden Technologies LLC. They make the race cams that many of the triumph tr4 racers use because they make the most and best power possible in north american vintage racing. The late Jack drews, and Tony Drews run Tilden's cams and others. Specifically designed lobes for the tractor engine, not chev lobe design (which some "triumph" cams are). These are "clean sheet" cams, not copies.

Tilden Technologies LLC have just finished the design of a brand new street cam for triumph tr3's and tr4's. This is going to prove to be an absolutely fantastic cam. It's 270 degrees duration (which is not a lot) but the lift on this cam is better than a lot of 290 degree cams and equal to many 300 degree cams. It is specifically designed for the triumph lifter which is .937" diameter. Many triumph cams are not specifically designed for this lifter and give up a lot of the potential that a large diameter lifter can permit.
this cam will work from low rpms all the way through to 6000.

I am so convinced that this is going to be the best hot street cam that i just ordered mine and sent 3 cores to them. I am building a 10:1 motor with long rods, dual side drafts etc.

I have no financial interest in Tilden at all. I would like to promote a good thing when i see it though. check out the site.
https://www.tildentechnologies.com/index.html

Rob
Click to expand...

Rob: Thanks for the report. This is very interesting. I'm not so interested from a racing standpoint, but I went to the Tilden website and read about their TR3 race car. I see that they run an A-type O/D, and listed the specs. as 8 forward gears. This got me a bit curious. Does this mean that they use O/D in first gear? How does the O/D deal with the extra torque loading? Is something done to the O/D to beef it up?

Thanks,

Frank
 
angelfj said:
Is something done to the O/D to beef it up?
Click to expand...
Mostly just turning the pressure up so it can handle the torque. There are some other changes (like optimizing the clearance between the clutches) to make it shift faster, but the basic mechanism is strong enough already.
 
trfourtune said:
Given that this is a street cam, i think a regrind will be fine unless you are ALWAYS revving the snot out of your motor.I plan to hit the track occationally and do some auto-x'ing.
Click to expand...
Probably you are right, Rob. But "probably" has an unwelcome element of uncertainty about it; and I felt it was worth some extra insurance. Seems silly to me to build a performance motor and then not use the performance, so I'm planning for it to see peak power and beyond on a fairly regular basis. Might do a little autocross as well, but I'm primarily just building a hot street motor. In some ways street is harder, because I expect it to last 100,000 miles, not just a few hundred races.

The story I got was that the factory was seeing what they considered unacceptable camshaft flexing, before they enlarged the front portion of the camshaft. You'll note that it has double the span of the rear half, because the oil pump & distributor drive gear is where the bearing would be otherwise.

While rpm is certainly a major factor in how much stress the cam sees, so is how fast it tries to accelerate the valves, and this camshaft accelerates significantly harder than the stock shaft does (which is what that bit about using all of the lifter foot is about). That's how it gets higher lift without a lot more duration. So, it is going to see more stress than the stock camshaft, even without turning any faster.

Plus, I trust Larry to know his camshafts. If he went to all the trouble of sourcing new blanks and negotiating a good deal on them; there must be a reason.
 
A reground cam should be just fine for street use or mild race motor. The top US TR4 racers are spinning their motors in excess of 7500rpm, and they're the ones that need to use blanks.
 
One point that Larry made to me was that the lifters cannot have a big radius on the edge and need to be re-ground. The lifters he reccommended are the BPNW performance lifter but they need to be re-ground, .010" or less chamfer/radius on the edge (they come with way more than this) and 50"-100" radius on the face(spherical). His reccommendation for lifter refacing is: Rocker Arm Specialist (530) 378-1075.
Rob
 
Interesting commment Rob - do you know if Larry has already worked with Rocker Arm Specialist on this? If this is a key thing to do, I'd hate to take it in to some generic shop and potentially walk out with lifters that weren't exactly what was needed.
 
He said he has used them before and this is who he said to send the lifters to. He knows they will do it right based on past experience. I assume he does not have specific instructions to them since he said i should tell them the requirements stated above.
Rob
 
I've no idea why the BPNW lifters have that big chamfer (the factory lifters don't have it); but a "generic shop" isn't going to do that. Last time I went through this, I had "Babe" Erson reface my lifters, and he left the edges sharp as original (with the large radius on the face, which is also original). He even explained to me why it should be that way!

Still, nothing wrong with sending them to RAS. They do good work at a reasonable price.

Something else to watch out for; some vendors are selling reduced diameter lifters with sleeves to mate to the block. These lifters work great with most cams, but not Larry's.
 
I think I misinterpreted Rob's discussion with Larry a bit in that I took it to mean the lifters need to be carefully designed along with the cam (ie specific high performance lifters, then machined to certain specs). Perhaps Larry is more giving his experience on what replacement lifters have worked well, but modifications needed if you buy them? I would guess if you had a set of good stock lifters, with reliable quality, then this step may be entirely unnecessary?
 
TR3driver said:
I've no idea why the BPNW lifters have that big chamfer (the factory lifters don't have it); but a "generic shop" isn't going to do that. Last time I went through this, I had "Babe" Erson reface my lifters, and he left the edges sharp as original (with the large radius on the face, which is also original). He even explained to me why it should be that way!

Still, nothing wrong with sending them to RAS. They do good work at a reasonable price.

Something else to watch out for; some vendors are selling reduced diameter lifters with sleeves to mate to the block. These lifters work great with most cams, but not Larry's.
Click to expand...

I think the only camshafts that use a V8 ramp design are the Erson cams. I say this because I know of no one that has had lifter problems when using the smaller Ford tappets with those camshafts.

If you use the reduced dia. Ford lifters on a very aggressive camshaft designed with the larger Triumph tappet in mind, there will be problems (ie: peices of tappets in the bottom of your oil pan or out the side of your block when they hit the crankshaft).

ALL lifters should be reground, regardless if they're new or used by the cam manufacturer (or in this case, a different company). Odds are you're going to need more than 8 lifters, as they all won't pass a rockwell test, new and old. g

It's best to talk to your cam grinder to know EXACTLY what they recommend for the lifter. If you are using Larry's cams, do what he says. If you are using Integral's cams, do what they say, etc. People too often start mixing and matching parts and get themselves in heaps of trouble down the road.
 
Larry said i could use original lifters but i should send 15-20 to RAS so they can hardness test the bunch and pick out the best ones. He said i only had to send 8 from BPNW stating the quality was consistent and hard enough. I only have 8 originals and one is very bad. If i had 20, i would go this route. But then, i would want to have them lightened as well so it would probably cost more in the end.
Rob
 
TR4nut said:
I would guess if you had a set of good stock lifters, with reliable quality, then this step may be entirely unnecessary?
Click to expand...
Problem is, there is no such thing these days. All of the original lifters are used now, which means they must be refaced before using with a new cam. And apparently everyone making "stock" new lifters is doing it wrong, with the result that the hardness is inconsistent from lifter to lifter. 100% testing appears to be the only answer.
 
That's one of the reasons for using RAS, they hardness test every one.
Rob
 
Latest from Larry is: the optimum lifter curvature is 80" to 100" but cam was designed to take 50" to 100" radius.
Rob
ps- he needs 6 orders to run a batch, so go buy yourself a christmas present !
money is always better than promised money. just do it.
 
I remember a similar thread a while back, where the term 'internet troll' was used to describe someone who I guess has fun just writing on forums to tick people off. Seems an appropriate term now as well. I never used the ignore list, but I think I'm going to use it now.
 
To "Maybe" - whoever you are.

You just registered and have managed to tick off quite a number of our members. Congratulations.

Please read the rules. This forum has managed to exist for the benefit of thousands of folks for years, only because we choose to maintain the decorum necessary to do so. If you care to contribute in a meaningful and respectful manner, please do.

Locking this thread. My apologies to those who began the discussion.

Mickey
 
Mickey Richaud said:
To "Maybe" - whoever you are.

You just registered and have managed to tick off quite a number of our members. Congratulations.

Please read the rules. This forum has managed to exist for the benefit of thousands of folks for years, only because we choose to maintain the decorum necessary to do so. If you care to contribute in a meaningful and respectful manner, please do.

Locking this thread. My apologies to those who began the discussion.

Mickey
Click to expand...

My initial thought was to just give him a warning, but then I read more of his posts in this thread and decided we don't need him here. He is only about the 6th person (out of more than 11,000) I've ever banned. What an a$$hole (yes, I know, I just broke my own rule).

(PS: This thread is now re-opened)
 
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