Titanium connecting rods forged aluminum pistons

[Superdave]

28 inches of water
intake exhaust
lift flow
.050 34 21
.100 63 53
.150 80 75
.200 96 93
.250 114 105
.300 138 117
.350 144 128
.400 173 138
.450 196 148
.500 215 153
.550 228 159

I took a spare head that I had laying around and cut it into 8 pieces and you can not believe the how much fun cutting the heads up was, they give you an unprecedented view at what you can remove from the cylinder, exhaust is were I got the most gain.

Nice!

On the exhaust side i have a bit more in the low lift, we're close at .4 lift and after that yours take off.

Here is the exhaust from a gen 2 head that i'm working on, i'm far from done though.


28" of water
.05 - 26
.10 - 55
.15 - 85
.20 - 107
.25 - 125
.30 - 135
.35 - 138
.40 - 139
.45 - 141
.50 - 142
.55 - 142


Good work man!


Now, what are your plans for the crummy gen2 lower intake?

[ForcedFirebird]

John, I didn't realize you used the 2.225" big ends! You realize that using those rods, you can more easily upgrade to the 3500 crank (steel forging)?

Either taking some off the rod end to compensate for the 2.249" rod dowel, or grinding the crank dowel to 2.225" would work.

Either way, I don't know if anybody has broken a crank or not (aside from negligence or oil failure), but the nodular iron seems to be holding for most.

Have you talked to your instructor about the trick I mentioned using an engine lathe to face the rods thinner? This will allow you to single point the titanium and not create too much heat across a large surface (ie hardening it).

Do you have the stock flow numbers for comparison sakes? As you know my bench as of now is being used for comparative testing more so than hard numbers and would be interested in your percent of increase at various lifts. Those numbers appear to be pretty linear over a stock set of flow numbers.

[john52216]

flow numbers

28 inches of water
intake exhaust
lift flow
.050 34 21
.100 63 53
.150 80 75
.200 96 93
.250 114 105
.300 138 117
.350 144 128
.400 173 138
.450 196 148
.500 215 153
.550 228 159

I took a spare head that I had laying around and cut it into 8 pieces and you can not believe the how much fun cutting the heads up was, they give you an unprecedented view at what you can remove from the cylinder, exhaust is were I got the most gain.

The titanium rods are out of a small block Chevy 350 they have a 2.225 big end and .927 small ends; I am machining the rod thickness from .934 to the same thickness as the stock rods (.842). When I ordered the custom pistons I had the pin opened up to compensated for the .927 pin and I am going to run a full float pin. On the big eng I used a bearing to go from the 2.225 to the 2.000 rod journals. You can use any small block (5.700 with a 2.225 big end and .927 small end) Chevy rod, alls you need to do is machine the side thinner and put bushing in the small end to run a stock 3.1L .905 pin and set it up for press fit or full float either way it can be done.

Any metal pushed past it limit becomes weak steel, aluminum, titanium it does not matter what it is made of.

[1988GTU]

Just think, you could spray bleach at the Russian submarine hulls and win the water war. lol

[60dgrzbelow0]

The sides of the big & small ends contact the crank & piston Blackjack.

I think BlackJack makes the proper observation that the major bearing surfaces would be handled... either by press-fit wrist-pins or main bearings with thrust surfaces on each large end that would prevent the sides of then TI Rods ever making direct contact with the crankshaft journals. I worked with Titanium as an aviation mechanic on the Sikorsky HH-3F Helicopter (1970-74) and was amazed at its lightness and strength... so my understanding of this unique metal comes from that experience. In our application...the Main Rotor Head had two sort of "Cookie Cut" thrust plates that held the five, fully articulated rotor head components plus the blades...the lower one was made of a high grade steel that four 4" inches thick... The upper one was made of Titanium...and was less than 1/2" thick...and was light as a feather...and twice as strong as its steel counterpart.

We were given some strict warnings on how to handle this plate when either bolting or torquing fasteners against its surfaces and other TI components... one which included the odd reality of how it readily galls and welds itself easily to other metal in friction contacts events... and the other was to NEVER let any kind of Chlorine Gas or Chlorine Bleach type chemicals get on the stuff....as it would readily corrode or dissolve this metal into Titanium Di-Oxide (which oddly now, I use in abundance as "Titanium White Oil Paint" when doing my landscape art). Other than that...the stuff was virtually bullet-proof. So my curiosity about how it can be lubricated conventionally stems form that experience.

[Superdave]

Hey John! Glad you spoke up about your build.

Dave, he is using Gen 2 heads to get that kind of flow! He told me he cut a head inti sections and examined them.

Brad, he is making everything there at the school, the professor told me they had the rods left over from something else and John wants to machine them to fit the rod pins (they are 327 small journal).

We had a good chat on the phone yesterday, and told him you guys might be interested in what's being built.

I know they can be made to flow pretty well but that's still up there..lol

[ForcedFirebird]

Hey John! Glad you spoke up about your build.

Dave, he is using Gen 2 heads to get that kind of flow! He told me he cut a head inti sections and examined them.

Brad, he is making everything there at the school, the professor told me they had the rods left over from something else and John wants to machine them to fit the rod pins (they are 327 small journal).

We had a good chat on the phone yesterday, and told him you guys might be interested in what's being built.

[bszopi]

Titanium is very strong, but once it gets pushed past its limits, its strength starts to go down significantly. Case in point - Russian submarine hulls are made of titanium, therefore allowing them to dive significantly deeper than US submarines. But, once they start diving to extreme depths, the titanium starts to become brittle (as Aaron mentioned), therefore the depths that the submarine can dive to decreases. Each time they get close to the new max depth, the titanium weakens again, and the max depth once again decreases. Same idea can be applies to connecting rods. Once they start to stretch due to extreme RPMs, the peak RPM they can handle decreases or they will fail.

[AaronGTR]

Yeah, I don't see using titanium as being a problem (other than expense) as long as they are designed correctly. Several hi performance cars have come from the factory with titanium rods including the Honda NSX. Only problem with titanium rods is they are really made for light weight and high rpm, and don't have that much power capacity. As evidenced by people with NSX's trying to boost them more than about 9psi and blowing motors. Even with a good alloy, titanium is just too brittle. If you want to make big numbers you really need forged steel.

[85maro]

LOL, my 2.8's pretty old and starting to make some funky noise. But seriously I know it's into the babitt on the rods. It makes that lovely noise on cold starts. Thought it was rocker noise at first but it goes away when I disconnect sp from that cyl. Before I swap in my hybrid it's getting nuked with n20.

Lubrication's not an issue, which is why GM's using it. The concern is titanium's ability to 'weld' itself to other materials under friction which I suppose might possible at certain times.

[BlackJack]

The sides of the big & small ends contact the crank & piston.

Agreed on the crank as related to the SIDES of the rod, but would the oil not adhere to the sides of the crank arms?

On another note, the small end of the rod should have a sleeve in it that the piston pin goes through. I sincerely hope that the small end of the rod in your engine isn't touching your piston elsewhere.

[85maro]

The sides of the big & small ends contact the crank & piston Blackjack.

[Superdave]

Hi my name is John Hunn and I am new to the site but have been a 3.1 enthusiast ever since I bought my first 1992 Chevy cavalier that had the z24 package and the 3.1. I now am a student at Ranken technical college and I am going there for high performance racing technology. I am machining and building up a 3.1 gen 2 with aluminum headed engine, I have ported the head and am flowing 235 intake and 150 exhaust, I bought a custom ground solid flat tappet cam with a 220/230 lsa 114+4 running a 1.62 rocker and for the bottom end running titanium connecting rods with custom machined forged pistons (2318 aluminum) running 10:1 compression, stock crank and running ARP hardware all over. I am going to run a 100-125 shot of nitrous. To also add some strength to the lower end and for reliability I have made a custom main girdle with the use ARP studs. this is just a little of what I am doing if you have comments suggestions any bit of info that I could use please let know if you would like info on the main girdle please let me know

Thanks John Hunn

235 and 150? at what lift and test pressure?


I've managed to get about 200 cfm @ .6 on the intake but that's useless since the customer's cam is less than .5 lift.



In for a full flow sheet, i can't even imagine the amount of material you had to remove to get those numbers.


Welcome by the way

[BlackJack]

The reason I'm asking is that AFIK... it is impossible to lubricate Titanium with standard, organic or even synthetic oils for that matter... because these lubricants will not cling to the light, white metal surfaces at all.

Maybe I'm not a genius, but if the rods are made of Ti, I would think that you would still have the bearing surfaces that would be lubricated that are not made of Ti, and therefore that would not apply in this case?

[85maro]

http://www.onepetro.org/mslib/servle...C-8521&soc=WPC

That was a joke, actually.