New Performance Cams for IDI, Not a Regrind. Interest??

[88 Ford]

cylinder head flow has a effect on torq and hp but not quite the way you might think. when I increased head flow on the intake side the torq numbers moved up the rpm range. if I raised the boost it would move back down again. but would peak at a higher rpm. If I raised exhaust flow the turbo would spool faster and torq came on sooner. The flow rate on the intake is less important than the pressure. lobe lift has a similar result. adding lift to the cam made bigger numbers in the higher rpm range. adding duration to the cam made everything move up the rpm range to but dropped boost at the low end. I think there are gains to be made from mild port work on the intake side, but dont make the port bigger just remove obstructions and port matching. The exhaust side needs the same work with special attention to keeping the size of the port and the manifold from changing size so the gasses dont expand until the turbo. "This info came from a article in diesel truck mag" . I put that info into the dyno and it made 8% increase in torq and 6%hp. on the stock engine, and 11% and 9% on the type4. Now when you look at piston design you find the IDI has a dimple and two round depressions for dispersing the flame from the pre chamber. The di engines can use a recessed dome piston so the fuel/flame can move out from the center. I want to do some research on piston design to find the best way to lower static compression and get good fuel/flame movement into the cylinder head at the same time.

So according to the program, you got those hp and torque gains just from port matching?

And as for the dimples in the pistons, aren't those dimples valve reliefs?

 

[88 Ford]

i dont understand why people think cam modifications on a turbo engine will have less effect than on a na then. clearly type4s cam makes a big difference on turbo rigs as well.

I definitely agree with you. I really gotta save up for a Type4 cam!

 

[racer30]

The dimples have a fancy name I can't remember right now but there for flame swirl into the cumbustion chamber. yes the power gains were at max torq, remember the number is not what I am after its the trend in the data that I am looking for. The gains in performance will be made at the end when we come up with the best way to build the engine for the application we need like puller vs daliy driver some mods are more expensive to do than others so you need to look at the big picture before picking the mods for the build you need. when you make adjustment in the flow rate in the program you can do it several ways, making the port larger, making the valve larger or increase the flow with a rating based on port size calculations. the program used a .4 rate as a default setting for this cylinder head when I tryed to calculate a rate I got .379 this would be a stock port with standard obstructions when you change the rate from ..379 to .4 I got the gain in flow. I looked at the list of heads in the program and there flow numbers I felt this would be like mild port work in this head. better to be conservative with estamates. I did some runs with bigger flow numbers and it pushes the peek up the rpm range. so that is the way I look at it. you want power up top port the heads for max flow. Im porting mine with matching as the goal and more work on the exhaust side. I havent made up my mind about the cumbustion side of the head yet.

 

[DragRag]

Does anyone already have the clearance number from the valves to the pistons so we can figure out what the max lift on the cam could be. Or, does a test need to be done with some putty or something still. By now someones has to have done this already.

 

[icanfixall]

Richardo cups are the name of the pistons depressions..... No... They are definantly not valve reliefs....

 

[racer30]

there are some computer models of valve train clearance that can be run but you need some fairly good measurments of the gaskets and valve pockets to get it right. then it will give a little video of the operation and you can make changes. I was planing on doing some tests just havent got there yet. my cam profile research has told me we are opening the valves later and closeing them sooner so valve clearance shouldn't be a problem until you start changing lift. adding lift to the type4 cam raised performance but also raised the rpm range the engine made its peek power. One more thing this program assumes its a di engine there are no ways to change the timing of the injection on the dyno so I think that is why it has bigger numbers than I was expecting. it optimizes the burn rate like its a psd. thats why I dont get freeked out about the numbers and just look at what changes the numbers.

 

[icanfixall]

Our pistons don't have valve reliefs in them. They have a depression called a Richardo cup and its for the flame front to swirl in. Actually the pistons come up above the top of the block as high as 31 thousands. I ran a set of Mahle pistons as high as 54 thousands above the block... That was not the correct thing to do... Every piston had a valve contact mark but.... You could not measure it and believe me.... I tried... You really couldn't even feel it but you could see it clearly. So... If the head gasket was 72 thous thick and the piston was up 54 thous only 18 thousands clearance from piston to head... The heads are flat so the only thing keeping the pistons from contacting the heads is the gasket thickness. I run the Felpro head gaskets because they are supposed to be 10 thous thicker than stock gaskets... I have miked them new at around 76 thous and used around 72 thous... Hope this adds to some understanding how these engines are designed....

 

[DeepRoots]

I've mentioned this before and got shot down....
If you are starting from scratch with a cam, why design it for hydraulic rollers?
why not solid rollers?

 

[built4tq1]

This thread needs a sticky

 

[idiabuse]

=DeepRoots;523490]I've mentioned this before and got shot down....
If you are starting from scratch with a cam, why design it for hydraulic rollers?
why not solid rollers?

Not enough rpm for solid lifter.
Titanium retainers would not help either.
Even at 5000 rpm it would not help make any
measurable power.
I would love to see someone testing this and finding
out on their dime.
A camshaft that pumps up the pressure sure would be cool!

Javier

 

[racer30]

wow.. solid lifter vs hydraulic, solid lifter engines need to have the valve lash checked on regular intervals to keep the engine in tune, In fact I will change the lash on my race engine based on what track type I will be racing on. hydraulic lifters don't need maintenance so they work well with the general public. hydraulic rollers are very nice to have they give the best of both worlds no maintenance and low drag on the valve train, just wish they would have put roller rockers on the IDI. hmm they look like big block rockers mabee..well I will look into that...

 

[DragRag]

wow.. solid lifter vs hydraulic, solid lifter engines need to have the valve lash checked on regular intervals to keep the engine in tune, In fact I will change the lash on my race engine based on what track type I will be racing on. hydraulic lifters don't need maintenance so they work well with the general public. hydraulic rollers are very nice to have they give the best of both worlds no maintenance and low drag on the valve train, just wish they would have put roller rockers on the IDI. hmm they look like big block rockers mabee..well I will look into that...

I have built one solid lifter full roller engine, it was monster that dynoed at 700hp. Not a diesel of course, but I digress. Main reason for not running solid lifter, yes the fact that they need adjustment to often. If anyone comes up with the clearanc between valve and piston please post. If you have a head unbolted already on an engine feel free to run a test. Keep in mind you need to account for the lifter that is not pumped up with oil that you are about to test it with. That will need to be overcome one way or the other.

 

[DeepRoots]

Not enough rpm for solid lifter.
Titanium retainers would not help either.
Even at 5000 rpm it would not help make any
measurable power.

and why is there not enough Rpm for a solid roller?
thats right!!! camshaft design. Well, not to be rude, but isn't that why people are wanting to redesign a camshaft? and don't give me the same old line about "our rotating assembly is too heavy"
Thats bs, I work with 10,000lb engines at work that spin 1800 rpms all day long, don't tell me that a 1100lb engine can't spin 7500....
Not to mention, if my 390 cast in 1964 can spin 6000rpms with a 46 year old cast crankshaft, 46 year old connecting rods and cast pistons, I'm pretty certain our 7.3 rotating assembly can handle pretty close to it.
I would also think that titanium retainers would be 100% unneeded at the rpm levels we are talking about.

wow.. solid lifter vs hydraulic, solid lifter engines need to have the valve lash checked on regular intervals to keep the engine in tune, In fact I will change the lash on my race engine based on what track type I will be racing on. hydraulic lifters don't need maintenance so they work well with the general public.

Indeed. great variance in a tight vs loose lash.
You mention "the general public"
last I checked the general public doesn't spend $700 on a custom camshaft for an outdated diesel pickup truck engine. Especially when gas motor cams are available all day in any grind for $150.

just wish they would have put roller rockers on the IDI. hmm they look like big block rockers mabee..well I will look into that...

I don't view this as an insurmountable problem.... I'm certain there is bound to be some roller that'll match up.
Custom pushrods are available from a variety of sources in all styles.

My point is that we have an engine that can feasibly make 400ft lbs and 200hp right? This is because it tops out at 3300rpms. Follow that line out to 5200 rpms with a cam that will allow that and your going to end up in 400hp territory. Sure it'll still accelerate like a fat man in the 100meter but you'll have the power when you get to speed.

out of interest, how much valve overlap is being added to aid in turbo boost with this proposed new grind?

Drew

 

[DeepRoots]

also, custom valve springs are available.... raise the pressure on the spring and you can make the whole works spin faster without worry.

on another note, how much can you mill off a piston? or more importantly how much can you cut out the valve reliefs

 

[idiabuse]

I had a 390, still got one too!
Injection pump for IDI has limits.
Time to start spraying raw diesel into the engine!
These engines are bullet proof OEM
I am all in for modifying but cautious also too.
I almost put a set of titanium retainers but that
would be like a wing on a honda when I thought about it.
I did put a set of higher spring rate valve springs though.
And a new set of pushrods with the copper ball ends.
I couldnt afford Titanium intake and exhaust valves though
Or knife edging the crank, that was expensive!
I did balance the whole schbang though!
I bought new casting heads too and wanted to port them
all I could do was open the ports to the OEM size, the rest
of the head was not worth porting.
I could of ceramic coated the chambers and valves, bling MONEY!
SHOULDA WOULDA COULDA!

I still like the way My IDI runs, 10.55 @ 64 MPH in the 1/8 mile

Javier