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

[DragRag]

Somebody, maybe ME! will have to get a baseline on flow specs for these Cylinder Heads we have, then we can get an Idea what lift the camshaft SHOULD be.
The OEM guy may have been right at .390 valve lift who Knows?
Until we get flow specs its *****!
My flow guy will ***** and complain the head is so heavy and he gonna make me lift that junk


Javier

If you get that number please let me know so I can present it. Gary has done some porting, maybe he has the stock flow figure for the head, and maybe he has a flow figure after porting. Chime in there Gary if you would and let us know, thanks.

 

[MotleyCrueCab]

If anybody has a spare head(s) that they want to donate to the cause, my head guy (boport racing ,www.bo-port.com works outta Freemont (san jose). Then we could get REAL flow numbers before and after porting.

 

[DragRag]

I have a set of heads off right now, and I live close to Fremont, but I will need the heads back to put on a 91' crew cab I am putting together. He probably doesn't want to port them for free and give them back to me, but I wouldn't mind......

 

[built4tq1]

I have some heads i wouldn't mind letting go. They are 6.9 heads with hair line cracks in the seats if intrested

 

[88beast]

we just scrapped a 6.9 with a bad bottom end and block but heads were great man knew i shoulda bought them for scrap price
also the stock cam cannot get more lift you just have duration to deal with
the lift is the same height of the bearing journals so no more lift without block modifactions
.390 valve lift with 1.5 rockers is .585 thats half an inch stock movement of the valve unless he meant lift of the vavle not on the cam but im assuming thats on the cam the cam i got is between 1/4 to 1/2 inch tall

 

[franklin2]

I don't know that much about cams, but the impression I get is they are like tires, a compromise. I am sure the stock cam is a compromise giving the best drive-ability, power, and fuel mileage.

What I am seeing in this thread is "we need a new camshaft for this engine and it will give us more of everything". I don't think that is true, you will have to lose something. I can't see gaining horsepower without losing low end pulling power. And if you set this cam up for higher horsepower, surely that's going to happen in the higher rpm ranges. So then to get anything out of the engine you are going to be bumping against the rev limiter all the time.

I believe a different more radical cam is going to require changes to the whole package, and will give the engine a whole different personality, which may be useful to some people, but if you use your truck for pulling and everyday use, you need to think of the consequences.

 

[88beast]

it is a comprimise but right now this is going from idea to lets make it happen phase which means its all sugestions and suggestions on how to do this so yes opening up the rpms more may cut the low end power but making the cam good at 4k will move the peak tq and hp up a few hundred rpm still usable and very nice option to have

 

[bike-maker]

The cam could be made more aggressive without changing the operating RPM of the motor very much. The idea isn't to just open the valves for a longer amount of time (duration), but to rip them open, leave them open, then slam them shut. The lobes on the stock cam are pretty round; the closer to square they are the better. This isn't as achieveable when regrinding a stock cam. And more lift can be had from a regrind to a stock cam by decreasing the cam's base circle.
The cams that can be had from Russ increase torque and horsepower while lowering the RPM that these 2 events occur at.

 

[88 Ford]

Does anyone even know where we could get any new push rods, lifters, rockers, or valve springs if we did need different ones? That would be another issue also.

 

[88beast]

i can find new valve train parts just let me know i got a couple guys who have been building motors for years one found me stronger pushrods double coil valve springs and upgraded lifters already

 

[DragRag]

This particular "new" cam project is DOA. It is just going to cost to much money having to buy that many billets at once. I am looking at going another route now with a regrind. If, and that is an if I can get the lift up to 450 or better, and that doesn't mean on both intake and exhaust, they very likely could have different lifts on them. There are already performance cams available in the 430 lift ranges from more then one grinder. The new direction for me at the moment after I find out what the maximum lift is is to get a cam designed to take this to a stage II type of cam. Basically, just move the engine to the next performance level. Get the engine turned on earlier, get more boost, and get the valves open more, and for longer at the best times. Once I gather more info I can go from there. At this point if anyone knows what the maximum amount of lift I can get using the stock pistons on an originally n/a motor I can go from there. The factory turbo trucks should have even more space then the n/a engines do, so I will engineer from there. I'd like to keep the valves no closer then about .040 from the piston. Might be able to push it a little closer then that, but that is it. Let me know what you have for info on this if you have it, and I can work on getting lobes designed based on clearances.

 

[DragRag]

we just scrapped a 6.9 with a bad bottom end and block but heads were great man knew i shoulda bought them for scrap price
also the stock cam cannot get more lift you just have duration to deal with
the lift is the same height of the bearing journals so no more lift without block modifactions
.390 valve lift with 1.5 rockers is .585 thats half an inch stock movement of the valve unless he meant lift of the vavle not on the cam but im assuming thats on the cam the cam i got is between 1/4 to 1/2 inch tall

I spoke with the cam grinder direct today. I was thinking the same thing, how can you get more lift from a stock cam that you need to grind on? it doesn't make sense to me either, btu guess what, it is possible. I will try and gather the info on how it is done and get it posted up. He has said that he already grinds a cam at .430 lift for our engine. I am looking for more then that though, and he said look, it hasn't been done that I know of on the idi so you are basically the test dummy. I am willing to go along though.

 

[88beast]

well the blanks what we looking at because i know some here will preorder
also if we keep talking theroy it may bring ideas to him for what to do

 

[racer30]

Custom cam grind

ok I have been running Performance trends engine analyzer program to find a better performing cam grind. Oregon cam grinding inc has a chart of lobe profiles to try. I ran 6 grinds that were on the chart, none made more power and torq than "type4"s Cam profile. the biggest problem with the stock cam is the 38* of overlap. then the 240* of intake duration and 250* of exhaust. the "type4" cam has -13* overlap and 187.5* duration intake and 198.6* exhaust. this makes the effective stroke 4.13" vs stock 3.76" this by itself increases the volumetric efficiency from stock turbo 6psi 97% to "type4" cam at 10psi 131%. I have alot of data to show this is a verry good grind to install in a stock engine with no mods. the only thing you need to do is if you dont change your lifters you need to clean them verry well because the lifters will need to "pump" up to take the slack out of the smaller base size of the reground cam. Check out this graph stock turbo engine 6psi boost vr "type4" cam 10psi to show a little mod and cam goes a long way. same fuel setting.

 

[DragRag]

Oh, I am not doubting type4's cam at all. But like you had stated, and engine that is stock with no mods. I am looking for a cam to to work with an engine with mods. I will not even be operating in the same rpm range. I just had my pump modified to spin my engine up to 4200 rpm, and I plan on porting my heads at a bare minimum. Type4's cam is great no doubt, I am just looking to take it to the next level with more lift, and different durations. What I need now is the information to tell me how much lift I can out on the cam with getting the valve to close to the piston. If someone has that info please advise. I am looking to go pretty close to the piston to achieve some good lift. let me know if you have that info.