[Skizzo]

@BigR Glad to hear you find my build interesting. I am doing this for fun and to try and get a little more info out to the people that we never really saw come to fruition in most circumstances or his hard to come by (cam stuff, porting). The temps for these pulls were about 90* with 90% humidity.

I might be able to find somewhere that could flow the head but I'm not sure I am going to do it. I am still trying to figure out what/how much I am going to do porting with the porting as I am an inexperienced porter.

No bigger valves or better springs as the only company that did make +1mm valves no longer exists and the 3.7 beehive springs are generally thought to be pretty good springs.

This truck is a mish-mash of "go fast for cheap" and trying to do things "right" at the same time. Really, I want to see just what a 3.7 is capable of without spending a ton of money to rebuild it.

With the head work and cams (and depending on the power band) I am thinking to rev the truck out to about 7k rpm but that is mostly dependent upon if the regrind could make enough power up there, which I'm not counting on. I'd like to get peak power closer to a little over 6k (it is 53-5500 currently) if I won't lose all of the low end.

 

[BigR]

I feel you on that. Remember 100lbs equals a tenth at the track. Maybe check these guys out https://www.artfiberglass.com/auto/2004Colorado.html

 

[Skizzo]

Oh trust me I am well aware of that rule of thumb. It is why I run a 2lb battery, fully stripped interior, lighter wheels and tires (at the track), and no spare/tailgate/bed cover.

The manual trans swap dropped about 100lbs itself compared to the 4l60e.

I could still do more (like fiberglass panels as you have linked, swapping to lexan windows, cutting stuff, and removing ac) but some of that starts getting expensive and some if it can't be easily reversed if I decide to stay street truck and not go full race.

 

[Skizzo]

Well finally getting started....

 

[Jaymes]

I think after you've done all you can do to that engine you should throw on a turbo...

 

[Skizzo]

Turbo would definitely be awesome but my thought has been nitrous all this time. We will see what ends up happening. What I'd really like to find is someone who has experience fly cutting pistons or camming these motors because I've got some questions and could use some guidance.

 

[caliheat]

Did you talk with that person who use to make cam blanks?
Was it emtech? They made some 4.2 cam blanks , but I think they stopped. Idk why.
It would be nice to have a head built with cams, deck the cylinder head for more compression and. Maybe clearance the Pistons while short block IN TRUCK!
Add 100 hp, without taking block out of truck would be awesome.
Iskiderian makes just such a cutter to deepen the piston valve releafs, in the vehicle. It looks like a valve with a cutter on bottom.
I could make one for out engines.

 

[Skizzo]

Did you talk with that person who use to make cam blanks?
Was it emtech? They made some 4.2 cam blanks , but I think they stopped. Idk why.
It would be nice to have a head built with cams, deck the cylinder head for more compression and. Maybe clearance the Pistons while short block IN TRUCK!
Add 100 hp, without taking block out of truck would be awesome.
Iskiderian makes just such a cutter to deepen the piston valve releafs, in the vehicle. It looks like a valve with a cutter on bottom.
I could make one for out engines.

@caliheat

emtechmotorsports yeah, efidiy on here. I've talked with him and gotten as much info as I can but he couldn't confirm whether the 3.7 would need the reliefs enlarged or not.

How much would you charge for making a tool like that? Link to the iskiderian tool? I've seen a few DIY versions using OEM valves that have been cut to make them a cutting edge and then you use them in the head of the motor with it on the engine to cut the reliefs. That is the way I was thinking of going about it if the pistons need to be relieved more than stock.


The plan for my 3.7 is to mill the head about .030, performance valvejob, ported, and a set of reground cams. Picking up ~100hp would be incredible but i don't think it is likely with reground cams since ours are really small/restricted to start.

 

[caliheat]

Valve tool maybe $100.
Emtech claimed 60 hp with 212* cam on the 4.2. Their total was 350 hp with some porting and only 8.5:1 compression.
If that motor added 1 point over stock, up to 11.3:1, that would be at 383 hp.
I feel they stopped making cam blanks due to longevity. I don’t think their blanks were heat treated, like all cams are.
Blanks are relatively easy, vs making finished, long lasting cams. Maybe iskederian could do heat treating.
My buddy was offered any free regrind for his 320 jimmy 6 cyl by iskiderian, himself! That was for his 38 Chevy at Bonneville, back in 1950! Lol.
Btw, if we could change our rocker arm, more ratio would give more cam.
If we could get cams, these motors would surprise a lot of bigger motors.

 

[Skizzo]

Valve tool maybe $100.
Emtech claimed 60 hp with 212* cam on the 4.2. Their total was 350 hp with some porting and only 8.5:1 compression.
If that motor added 1 point over stock, up to 11.3:1, that would be at 383 hp.
I feel they stopped making cam blanks due to longevity. I don’t think their blanks were heat treated, like all cams are.
Blanks are relatively easy, vs making finished, long lasting cams. Maybe iskederian could do heat treating.
My buddy was offered any free regrind for his 320 jimmy 6 cyl by iskiderian, himself! That was for his 38 Chevy at Bonneville, back in 1950! Lol.
Btw, if we could change our rocker arm, more ratio would give more cam.
If we could get cams, these motors would surprise a lot of bigger motors.

They used to make 5 cylinder cam blanks but they wanted ~1000 bucks for em IIRC and the market for them here is really small so no sales, no reason to keep making them. I'm no expert on cams either but I'm pretty sure you would heat treat the actual cams after grinding, not when they are blanks. Heat treat the blanks and you'll just cut it all off when you grind the cams.

350hp w/ 8.5:1.... on 4.2 with a 212* cam... Stock 3.7 cams are 165* intake and ~180* exhaust. I could be wrong but I doubt a regrind on our stock cams could net 50* on the intake and ~30 on the exhaust. HOWEVER, my truck as it sits put down 236WHP and 247WTQ which would mean I am making around 280hp/290tq at the crank so with a decent port job, valvejob, regrind, and head mill i could probably be around 330-350, maybe?

Our stock rockers are already a ~1.7 ratio I believe so not sure how much better we could get to, if anyone even made them for our engine. Jessel makes a set for the ecotech that would work but they are the same ratio and a set is only a paltry $4000.


hmm might be worth it to do the valve tool. I dunno, maybe maybe not.

 

[caliheat]

I here our exhaust ports are a little small, 65?cc, but intake is around 190cc.
Even with regrind, intakes probably don’t need much work, if any.
Long stroke motors need more exhaust valve open time to get exhaust out. Maybe porting exhaust would free up more torque & hp.
Granitelli advertised roller rockers when the 4.2 cam out, maybe those were the Ecotec parts. I have a cnc mill that could make some alloy 1.8 roller rockers ... plus regrind would give you ~ 17% more cam. ( I would need to build 20 sets to break even on r&d time, IF it’s even possible).
Honestly, if I didnt have the wonderful CARB to deal with I would just turbo it!
It’s really looking like a 5.3 lh8 swap is best bang for buck in California.
I could swap a 7.0l legally, but don’t even think of adding a little turbo to the i5 !

 

[Skizzo]

I here our exhaust ports are a little small, 65?cc, but intake is around 190cc.
Even with regrind, intakes probably don’t need much work, if any.
Long stroke motors need more exhaust valve open time to get exhaust out. Maybe porting exhaust would free up more torque & hp.
Granitelli advertised roller rockers when the 4.2 cam out, maybe those were the Ecotec parts. I have a cnc mill that could make some alloy 1.8 roller rockers ... plus regrind would give you ~ 17% more cam. ( I would need to build 20 sets to break even on r&d time, IF it’s even possible).
Honestly, if I didnt have the wonderful CARB to deal with I would just turbo it!
It’s really looking like a 5.3 lh8 swap is best bang for buck in California.
I could swap a 7.0l legally, but don’t even think of adding a little turbo to the i5 !

That would definitely be awesome to get some higher ratio rockers but it sounds...expensive! lol.

My plan with porting is pretty much all exhaust side, just going to clean up the intake side casting flash and such. Definitely a big difference in size between the intake and exhaust ports.

Also I misquoted the exhaust cam specs... here are the intake and exhaust cam specs for the 2.9/3.7

intake cam: 160* @ .050" 0.257" lobe lift 0.434" valve lift
exhaust cam:168* @ .050" 0.221" lobe lift 0.372" valve lift

 

[efi-diy]

Been a while since I've been on here. The cam blanks are not hardened to allow the cam grinder to remove metal quickly.
The lobes are round on the blanks.
Here is the process to convert then into finished cams:
copper plate (need to remove heat during the grind)
Rough grind the cams
heat treat
Straighten the shaft
finish grind
inspect
ship

I do have an open cam core buy on the 4200 swap facebook - only making 4200 cams - for a 5 cylinder cut the last to lobes off before sending them to the cam grinder. If enough people from here step up then we'll do dedicated 5 cylinder blanks US$450/pair + shipping/paypal