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Thoughts on MHS PI H/C and stock bottom end

56K views 322 replies 30 participants last post by  Grog6 
#1 ·
Okay, so this spring the bird's getting a built 2004 trans and 3,500 stall 10" TC from Alan, with the expectation that next winter will bring ported heads and cams. I've done some looking around and I'm thinking about going with Nick's stage 2 PI head and stage 2P cams combo, with the modified valves etc. I'm hoping for a fun street toy; 280-290 RWHP is the goal.

The thought is to swap the heads and cams, keep the PI intake, and leave the stock bottom end be (I won't be pulling the engine). I've read some varying info on the durability of the stock bottom end when it comes to RPM though. I understand the stock crank should be fine in such a combo up to 7000 or thereabouts, here the worry is the rods. My question is if I'd be safe with the stock bottom end with such a H/C combo, and what a reasonable RPM limit would be such to keep things in one piece. I'm assuming it should be okay up to 6300-6500, but I'll be the first to admit I'm not the most knowledgeable on this topic.
 
#2 ·
Like you sir, I'm no expert. From what I've heard, you should be fine up to 6,500 RPM np with the bottom end being stock. That's just my opinion, but I have done lots of reading on this, so I think it's a good opinion lol.

I'm sure someone more knowledgable will chime in here :D
 
#4 · (Edited)
Arrighty, good to know.

Now if I may, I read a few older posts of A-train's and it sounds like 24# injectors and a 190lph fuel pump will also be in order. Question here being, should I just go with 30s so I have plenty of additional headroom, or would that be overkill for my application? The car will (hopefully) also be getting ported manifolds, possibly a new plenum and TB later down the road, and I plan to keep the 80mm GT MAF.
 
#6 ·
Thank you once again GM. Don Lasota will be my tuner. :thumbsup:

... although I wish I could just do it myself without blowing everything up... :)
 
#9 · (Edited)
Having worked in Ford dealerships for over 20 years and also knowing many techs.
I also worked parts on back counter so I have decades of experience on what fails and what doesnt.

Basing my opinion on the fact that you are doing a street car around 300 h.p.

The bottom end is probably the strongest part of a stock 4.6 Romeo.

I'd leave it alone.

If the motor was out of the vehicle I'd put some new bearings in it.
Freshen it up.......tighten it up a bit.
Of course some people like a gap there for less drag on crank.
In fact I knew a guy that built his motors loose........of course every journal was equal to the other but his engines revved up quicker than any other builder I knew.

so.............cough.......
still
Other than that I wouldn't touch it.

oops cept maybe a new nice oil pump
 
#10 ·
Yep. On Nick's website the head/cam combo is highlighted as part of a 300 RWHP combo but he and I are both expecting closer to the 280-290 I mentioned above. That's mainly due to the T-bird's auto trans and IRS, plus I'm choosing the stage 2P cams over the stage 2.5 which is a sacrifice of about 5 RWHP for a wider torque curve. Daily driver, after all. ;)

My parts list looks like this so far:

24# injectors
190 lph fuel pump
Braincoating ported/ceramic coated manifolds
Modular Head Shop stage 2 PI heads (Romeo)
Modular Head Shop stage 2P cams
EEC dyno tuning by Don Lasota
3500 stall 10" DirtyDog converter
2004 GT 4R70W built by DirtyDog

And of course all the supporting stuff to go with it all. New timing chains and guides, stamped trigger wheel, rebuild/clean the injectors, new front and rear main seals, etc.

:)
 
#12 ·
A nice surprise, Darren. :)

BTW, Michele said she'd have Preston get in touch with me over the weekend about getting some ported/coated manifolds. I'll ask him to drop you a line as well when he gets in touch with me.
 
#16 ·
All righty - I have my 24# injectors here now. They are the older Bosch EV1 style, same as these:

<img width=200 src="http://fuelinjectorconnection.com/shop/images/uploads/24lb-EV1.jpg"/>

I replaced both O-rings, inlet filter, pintle cap and spacer on all of them.

My question. IIRC the car has EV6s stock on it now (see pic below to confirm me on that), and I know the two use a different style connector. If I had the car available to me now I'd just go out and check for myself to be sure that I can't just use the 24s I have with my stock hardware, but since I don't I'm here. I see myself with two options if connectors are indeed different:

  • Sell the EV1s, buy EV6s
  • Buy pigtails for EV1s and splice them in
With option 1, I would use the money from selling the rebuilt EV1s for the EV6s. I know I'll spend more on a set of EV6s than I did on the EV1s (I got a great deal on the EV1s - thanks Darren!). I would also most likely rebuild the EV6s as well, depending on what I would end up with.

With option 2, I would have to buy 8 pigtails which would offset some of extra cost from upgrading and rebuilding EV6s.

Now, aside from my not having to splice the pigtails, would there be any advantages to using EV6s over EV1s in my application (e.g. better atomization/response time. etc.)?

Here is a shot of the stock injectors currently on the car. Took this pic when I did the PI intake swap 2 years ago.

 
#17 · (Edited)
Brandon, you're killing me here. Look at the connectors on those two injectors and I think you will find they are EXACTLY THE SAME CONNECTOR.

I know because I have the same injectors you do - both sets! If you don't believe it, take them out and try to plug them in on the car.....

Also, I know that is a popular swap (I was going to do the same thing), but after seeing the difference between the way those skinny Bosch Type III injectors atomize the fuel, and those older Type II (the blue ones) do it - I'm not going to use them.

Let me find the video so you can see what I'm talking about.....

Here is one I found on youtube:
http://www.youtube.com/watch?v=VfynoxL2RZI

You can just search for "type iii bosch" on youtube and check out other videos. Type III Bosch really does a nice job of atomizing the fuel while the earlier types look like a squirt gun!
 
#18 ·
That's what I was hoping but wasn't sure of based on the pics and reading. :)

I was thinking about "I could just try plugging my 24s into the car..." but since the car's at the body shop right now, that was out of the question...

Maybe when I get my car back I'll let some of you guys rest for a little while. Until then... :diablo:

But yes, if there's a definite advantage to using the newer style over the older style, I'll upgrade. I'll be close to the upper limit of 24s, so they need to do their job well.
 
#19 ·
Well, the only problems is the older styles will hurt mileage a little and increase wear on the engine because raw fuel rinses the oil from the sides of the cylinders faster than well atomized fuel.

Of course, we're talking long time longevity, so it depends on how long you plan on keeping the car (or how long before you want to rebuild it again).
 
#21 · (Edited)
#23 ·
That first set you listed is the different connector. The second set you listed, I would get a part number from the seller cause he says that's a "file photo" and not the particular set you will receive. Plus, I've never seen a 5.0L (old 5.0) that came with 24# injectors.....

Just my .02, hope it helps.
 
#27 ·
A little late but just figured I would throw this out. Your RPM limit should be be between 6500 and 6700. I say this because any higher and your killing your acceleration and any lower and you are doing the same. Your shift points will be in that range I am guessing for optimum acceleration. Just remember this, the lower you shift, the slower you go, but the longer your engine will last. Me personally, I wouldn't hesitate to shift at 6600 all day long. Any higher and I would start saving for a shortblock.
 
#30 ·
I said, "...may..." smart-butt. :tongue:

Just trying to show all the options.....
 
#31 ·
Lol... you two guys...

I'm hoping to find a set of them for under $100, even $80 if possible. I've got roughly a year to accumulate parts, so I'm not in any hurry. I used the instructions on oldfuelinjection.com for cleaning/rebuilding the injectors; it seemed to work well. :)

GM, PM me your paypal address and I'll send you the money for the gear.

paintme, thanks for the input. I think 6500 sounds like a nice, happy shift point. It depends how the datalogs look, but I feel that's a safe number.
 
#32 ·
The biggest Important unknown I've found on these cars is the condition of the oil galleys and lash adjusters in the heads. :)

Few of us got these new... :rolleyes:

The engine in Lazarus, which has had synthetic oil every 2500-3k miles since it had 30k miles on it handled bouncing off the 5500r rev limiter multiple times with no engine issues at all. (Not a ride I would recommend; check those engine mounts, lol.)

The Red Cougar dropped a valve the first time it hit the 5500r rev limiter after a PI intake swap, lol. That engine was nasty, even tho I'd been running good oil and seafoam thru it, as I found out postmortem.

As far as the injectors, check local JYs for lincolns with blown motors; they are 24#.

You might luck across an aviator motor for cheap. :)
 
#33 ·
#35 ·
Okay guys, more advice just because I'm impatient! :)

The car is going to Alan this weekend for my torque converter and transmission. After that I'm getting a tune from Don to account for my ability to shift higher. My rev limit of 6500 with my planned setup makes more sense having heads that flow well, but I doubt there will be much point going that high with the stock heads. Not to mention I don't know how safe the stock valvetrain would be up that high. The car would have to last as my DD up through October at the very least. ;)

I'll eventually get some datalogs with the acceleration rate so I can have Don optimize the shift points, but like I said, I'm impatient and am curious to know what I should expect. Will I run out of power by 6000? 6300? And with the stock springs etc., will it even be safe that high?
 
#36 ·
6500 on the stock valvetrain isn't a problem, it's other stuff.

130k on these cars is "well broken in." As long as it's had the oil changed on time, it will rock.

You're dealing with the tranny stuff that IS an issue.

I've seen Lazarus bounce the tach off the stop (a few times) while I was breaking wheels; I didn't have any input at the time, but I remember going "damn!" (as I was trying to turn off the key...)

The car is fine, and isn't using any more oil, and still has the same 22mpg mileage.
 
#37 ·
Yeah, having Alan's trans build coming before all the extra RPM was a no brainer, at least for me... :)

I change the oil every 5k; full synthetic. When I did the cams a couple years ago everything looked reasonably clean up top, so I'm not worried about sludge or grime. The car does seem to use a little oil - a quart or so between changes (that 5k is yearly). I get 20ish in the city, 22-23 on the highway.

I guess what I'm worried about is valves floating on the stock springs.

Thanks for your thoughts Grog, it's always appreciated and welcome. :)
 
#38 ·
This is what I would do if I was you. After you get the car back from Alan, take it to a dyno - it's well worth the $50-$75 to know what kind of power "under the curve" is going on. That will tell you if you want to lower your rev limiter or not. If not, then worry about what will need some extra work (like bee-hive valve springs) if you continue to rev it to 6500.

Personally, I think you're gonna find that going that high isn't optimum for your pulling power, but what do I know! :D Makes sense to me, anyways.
 
#39 ·
I'm with Rick I would wait til you get your heads and cams in THEN get your tune from Don; assuming your getting a dyno tune...

On the other hand if your getting the 'off the shelf' tune (I don't know if you have a hand held tuner or chip or what) but on my SCT flip chip I can hold a couple of different tunes. So why wouldn't you get the tune from Don but just run your current tune until you get your heads and cams in then run the new tune? :zdunno: That way you won't have to risk running your stock heads and cams all the way to 6500 rpm
 
#40 ·
I need to get my shift points adjusted regardless due to the higher stall and gears. Plus I'm anxious to get the loonie tune off my car, there are a few quirks with it that have been driving me nuts over the last 2.5 years. I've got an xcal2.

I'll probably get it dynoed anyway to see what the curves are like. Plus I'm curious to know what the numbers are with my setup. Just for the graphs, no tuning. Just because I can run it to 6500 doesn't mean I will; the graphs and logs will dictate that.
 
#41 ·
Great! And post those graphs in the dyno thread! Maybe there is a 'dyno day' coming up near you - those are generally cheaper...
 
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