Cam Upgrade to 7.3idi NA diesel

[BIGR3DMF]

Hello,

I am just wondering how effective/worth it/possible a cam upgrade is the a NA 7.3 idi. I do not want to go the turbo route because of the high compression ratio and also I’d feel safer with a turbo block which I do not want to invest in. I’ve seen cams and what not on some 7.3 idis, but I want to know if I’d need to overall lifters and pushrods as well, and of course the IP would need tuning. Just seeing what info and experience is out there, thanks.

-Big Red

 

[Black dawg]

From what I have heard and seen, the cam does make some more power, but in my opinion I dont think it would be worth tearing into one to do the cam. If it was apart, then I would.

The compression ratio is a NON issue unless you are trying for really big power numbers.

 

[FrozenMerc]

Upgrading the cam is always a good idea. The challenge is getting the cam to have the right specs so that it is optimized for the engine configuration. Finding some one who is willing to grind an optimal NA pattern (or even knows what that pattern would look like) could be a challenge. Most of the grinders I have talked to regrind for turbo applications, and a forced induction cam is normally not optimal for an NA motor.

 

[rewbrooks50]

Russ is the cam man. @typ4

 

[IDIBRONCO]

You will also need to upgrade to the Comp 910 valve springs. By doing that, if your lifters have very many miles on them, you will also need new lifters so that they are strong enough to overcome the stiffer valve springs. The block is also not an issue unless you're trying for big power. The bottom end of our engines is overbuilt from the factory. Another thing, I haven't seen definitive proof that there is any differences between N/A and Turbo blocks other than the external oil port that is bigger on the Turbo block. I've seen references to thicker main bearing webs on Turbo blocks, and I've also seen no mention of that whatsoever when an "expert" does a write up on the differences. Until I see where some reputable (a member on here) actually measures both, I'm saying that the only difference is the one oil port. That oil port is also a non issues since many, many members on here run their turbos with oil fed from a smaller port.

 

[The_Josh_Bear]

How feasible is it to swap cams without pulling the engine? This ain't no OHV 4-banger!

To add to the above post, the @typ4 cam IS an N/A cam. Though by all accounts it does very well with the turbo application. So if you're worried about N/A power, you have a solution. It still won't pull like a turbo, FYI. If you do it get a before and after dyno run so we will have numbers finally after all these years!

 

[TNBrett]

You will also need to upgrade to the Comp 910 valve springs. By doing that, if your lifters have very many miles on them, you will also need new lifters so that they are strong enough to overcome the stiffer valve springs. The block is also not an issue unless you're trying for big power. The bottom end of our engines is overbuilt from the factory. Another thing, I haven't seen definitive proof that there is any differences between N/A and Turbo blocks other than the external oil port that is bigger on the Turbo block. I've seen references to thicker main bearing webs on Turbo blocks, and I've also seen no mention of that whatsoever when an "expert" does a write up on the differences. Until I see where some reputable (a member on here) actually measures both, I'm saying that the only difference is the one oil port. That oil port is also a non issues since many, many members on here run their turbos with oil fed from a smaller port.

I took a set of calipers to the two blocks I have a 92 n/a and a 93 factory turbo block stamped with a “T”. No difference what so ever in the thickness of the main bearing webs. The oil feed seems to be the only difference between the two blocks.

 

[IDIBRONCO]

I took a set of calipers to the two blocks I have a 92 n/a and a 93 factory turbo block stamped with a “T”. No difference what so ever in the thickness of the main bearing webs. The oil feed seems to be the only difference between the two blocks.

Thank you. This is what I've been wanting for several years. I don't have access to a Turbo block or I would have done it myself. Any jack(donkey) can call him/herself an expert, write up an article, and say whatever they wanted to.

 

[typ4]

My cam is a drop in, I do recommend the 910 springs since our springs are 30 ish years old. I have not seen lifters fail. I take them apart, clean the varnish off and reassemble. no issues in many sets.
Cams are in stock.
And I need cam cores.

Russ Repair

russrepair.com

 

[typ4]

Thank you. This is what I've been wanting for several years. I don't have access to a Turbo block or I would have done it myself. Any jack(donkey) can call him/herself an expert, write up an article, and say whatever they wanted to.

I have seen some published info about the block differences and also have only confirmed the oil galley. That said I have a U-Haul engine that has what appears to be a new block, no serial numbers, with the larger oil galley. when I tear it down for balancing ill compare it to an N/A block.

 

[NeverHave-I-Ether]

If you could do a before and after dyno of the type 4 cam that would be awesome. No dyno sheet with just a cam swap exists, and it would be nice for someone to post the information.

 

[IDIBRONCO]

My cam is a drop in, I do recommend the 910 springs since our springs are 30 ish years old. I have not seen lifters fail.

I have the Comp 910 springs on the engine in my Blue Truck. Even though I wasn't able to run your cam in it, I did have to replace the lifters. I had an intake lifter that wouldn't open the valve so I had a dead miss on that cylinder. I put new lifters in my engine and I don't have any issues now. Maybe I could have cleaned the old lifters up and they would have worked. I don't know. I figured that the springs inside then were weak. That's why I suggested new lifters.

 

[typ4]

The lifters get varnished and they stick down. The springs keep the disc pushed against the bleed hole so def a possibility.
11% torque and HP across the board NA when the cam was dynoed many years ago.

 

[chillman88]

11% torque and HP across the board NA when the cam was dynoed many years ago

Stock that would be... +20hp and +40tq? That's not bad. Especially if it's coupled with a turbo upgrade too.

 

[IDIBRONCO]

The lifters get varnished and they stick down. The springs keep the disc pushed against the bleed hole so def a possibility.
11% torque and HP across the board NA when the cam was dynoed many years ago.

Since we're on the cam, lifters, etc. subject here, how much clearance do we need to have between the valves and pistons? It does go along with the cam swap.