In this thread I'll be rebuilding a 4.9 that had 90,000 miles on it. It was from a Chicago area car that was a salty grimy mess on the outside. When I took it apart it was in pretty good shape and everything was still within specs. I've been reading as much as I could on these engines here on Pennock's and elsewhere. PBJ, Rockcrawl, Kento, fourpoint9, jeffndebrus, and many others have detailed plenty of swap information and I've learned a lot from each of them but I thought there was a distinct lack of internal performance mods being documented for this engine. Not that they're not being done, just that they're not really being documented. So I thought I'd start this thread. I am by no means an expert but I want to share what I learn throughout this process and hopefully learn from others as well. If anyone finds errors please let me know, I'd like to make this a document that people can learn from in the future.

Projects that I have planned are:

1) Cam upgrade
2) Heads ported and polished
3) Crank polished
4) '89-'92 Allante intake
5) Increased diameter intake valves
6) SBC valve springs (to raise rpm limit before valve float)
7) All new bearings, rings, oil pump, and gaskets
8) Lots of chrome and polished parts
9) Engine wiring
10) Spec Stage III clutch and custom flywheel mated to a Getrag 5-speed
11) MAYBE headers...

I WAS going to bore it .040" over and use Northstar pistons but that would require removing all of the sleeves and sending them out to be bored and frankly, for the small increase in displacement/power it wasn't worth the cost and hassle. The N* pistons would raise the CR to somewhere in the neighborhood of 10.5:1-11.0:1 with stock being 9.5:1. It might be a great idea for someone who is trying to squeeze every last drop of hp out of this engine and it would be cool to be able to put 5.0 emblems on my car... but my line of credit is stretched thin as it is and I still haven't really DONE anything! Something had to give and I decided it was the pistons.

Here's how this poor battered beast arrived at my house:

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-Rick Stewart
85GT 4.9V8/Isuzu 5-spd in progress...

[This message has been edited by GT (edited 08-02-2005).]

it's my understanding that the n* motor is arround 4.3L while your motor is a 4.9. For the n* pistons to be larger, then the stroke would have to be significantly shorter. Just wondering if this is correct, or am I confused?

I ask because I am going to do a 4.9 swap and am trying to learn as much as possible about this motor

using the Nstar pistons require using the Nstar liners .... You will also have to get a custom headgasket, But in my opinion using the Nstar pistons give little to no gain, Only bragging rights that it's a 5.1 liter.... They will cost you alot as well, Plus you will have to do a bit of machining. I would focus elsewhere instead of the pistons.

If you want to start somewhere start here

In the pic these were just started and only gasket matched....

As you can see the intake manifold and heads can use a bit of porting..... Im going to messure up some Quad 4 pistons and see what I come up with..... The quad 4 pistons will actually reduce the compression if they fit. for what im planning on doing (top secret ) This engine is extreamly restrictive on the manifold and heads.
I will probally custom make my headers.

I have not got to the cam, valves and springs with mine. Frankly I have no clue what im gonig to do in that department. I heard tricks to using the 4.1 springs but will have to research more.

It's a bit costly but I would go for getting the crank balanced.

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[This message has been edited by 86fieroEarl (edited 04-08-2005).]

Rick,
There are restrictions in the intake manifold where the pushrods pass through. You can press some thin-wall steel tubing into the pushrod holes and then grind the ports out for maximum flow without fear of grinding through. Use Loctite 603 on the tubes. The intake ports should be matched to the heads after the heads are installed.
I enlarge the throttle bores on the intake to 2". Some guys like to cut an air gap between them as well. I radius the bottom of the bores into the runners. The throttle body can be bored to 2" or replaced with a larger TBI unit with a block off plate where the injectors normally go. There are two vacuum ports that are overdrilled from the factory, they need to be plugged with aluminum dowell before boring the stock throttle body to 2"
you can shave the heads to increase compression a bit, I go .050". Smooth the chambers and radius the sharp edges. Unshroud the valves. Just standard procedure for improving a stock cast iron head. The four end ports can use a lot of work on the intake side where the walls bulge in for the rocker support bolts that come down from the top.
I have cad files for 4.9 header flanges if you decide you want to build headers.

Jon

The Northstar is a 4.6. I've spoken to people who have used N* pistons and they are a direct swap with bored .040" over 4.9 liners. The pins are the same size and are in the same location as the 4.9 pistons. I was told to use the 4.9 pins with the N* pistons and 4.9 rods. I had not heard of using N* liners... see, learned something new already! Here are some pictures of the 4.9 and 4.6 N* pistons. The piston with the rod attached is the 4.9 piston in all three shots:

[This message has been edited by GT (edited 04-08-2005).]

quote Originally posted by rockcrawl: The N* pistons use 4.9 liners with 1mm overbore and stock gaskets. For anyone interested in setting up there 4.9 with N* pistons contact: Bud Adelman @ Bud's Out Back 1920 E. 17th St. Tucson, AZ 85719 520-623-8880 He is setup to bore and hone the cylinder sleeves and supply the N* pistons, rings, & pins. Plan on sending him the sleeves from your engine to be machined.

ahhh So one can use 4.9 liners with N star pistons, Ppl have told me you need the nstar liners as well. Oh well I learn something everyday

BTW were can I get the cad files for the header flanges? I will check out your site tonight and find more info.

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Thanks for posting that info Rockcrawl. I may take you up on the header flange CAD drawings. I'm using an Allante intake which is totally different than the stock 4.9 manifold, as you probably know. But I'm really glad you posted that info here for other folks wanting more power with the stock intake. I'll see if I can post a picture of the Allante intake.

Earl- I called Bud one day a couple of weeks ago and he is a huge wealth of knowledge on this subject. One interesting note, though. The factory manual says to keep all liners matched with a marker to their original locations because they were fitted at the factory. Bud says it doesn't matter as long as all the sleeves stick up .000-.080" above the deck surface before you take them apart. They should all fit in any slot when you put them back together. If any one sits lower than the deck height you simply have to remove the liners and machine the deck height slightly until the liners stick up above the deck up to .080".

[This message has been edited by GT (edited 05-04-2005).]

The Allante throttle body is a two stage unit which opens the small bore under light throttle and gradually opens the large secondary bore as more pedal is given. The primary bore is 45mm and the secondary is 54mm.

Here is a picture of the upper plenum with the runners that go down to the lower intake:

[This message has been edited by GT (edited 02-19-2006).]

How much does a 4.9 weigh?

Not much more (if any) then the stock 2.8LV6

I've heard estimates of 360lbs. The 4.5 Allante engine that I have ( same block, different stroke) has 342lbs written on the shipping tag but it was missing the alternator, A/C and flexplate.

[This message has been edited by GT (edited 04-09-2005).]

Can you use the 4.9's ECU with the Allante intake or do you have to use the Allante's ECU?

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fourpoint9
87 notchback 4.9L swap in progress

I'd have to defer a definitive answer to Rockcrawl on that one as he's the expert, but he said I could use my 91 Deville CPU and his chip with the Allante intake. He said it'll probably run well as is but a little time on the dyno would be useful to dial it in perfectly.

quote How much does a 4.9 weigh?

They are 371 lbs with all accesories attached.

quote Can you use the 4.9's ECU with the Allante intake or do you have to use the Allante's ECU?

The ECU is the same, they just use different calibrations on the removable chip.

My rings, bearings, gasket set, and oil pump showed up today so I can start getting this thing put together soon. I spoke to the head shop today and they're going to be looking for some 1.94 intake valves that'll fit without changing the geometry. I was told if I went 2.02's I would need a 1.60 exhaust andI don't think 2.02's and 1.60's will fit side by side in that head. But if I'm using 1.94 I can use the stock 1.50 exhaust valve. Anyone know anything about why you can increase the intake valve size and leave the stock exhaust valve alone up to a certain size?

Here's a picture of the sleeves. I've decided to go ahead and punch it out to 5.0L. The sleeves just come right out if you wiggle and pull. There is an o-ring that goes around each sleeve and seals off the oil pan area from the coolant in the block. I'll be using the Northstar pistons with my freshly bored sleeves. While I have the whole thing apart I'm having the whole rotating mass balanced. The rods, pistons, harmonic balancer, flywheel, and crank are weighed and lightened or weighted where necessary to make the rotating assembly as vibration free as possible.

You are definitly going for the best looking 4.9 award. Looks very nice man.

Wow!!

WOW! That intake looks awesome. I was going to polish my Allante intake, but it was way too much work. I ended up polishing the top part and painting the runners and lower intake black. After seeing how good your intake looks polished I wish I would have done the whole thing! That looks amazing!

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Bottle Fed 4.9 V8 5 Speed
87 4 cyl 5 speed coupe
I drive way too fast to worry about cholesterol.

quote Originally posted by GT: WOOHOO! I just got my Allante intake and Eldorado valve covers back from the polisher today. The valve covers were going to be chrome plated but it turns out they are made of magnesium and can't be plated. So the shop polished them instead...

Holy sh@t that looks nice..... Who did that and how much ?

Thanks guys.

FM88- I saw your page and couldn't believe you were going to attempt it yourself. I tried it and it was nearly impossible to get a good surface with a 15K rpm Dremel tool. So I had someone else do it. Luckily real estate is insane here so I've got some home equity helping me out with this swap.

Earl- I hate to say what I paid since I just had a run in with the wife about it, but it was slightly over $1000. The rocker covers were $200, the lower intake was $250, the upper intake was $400, I had a few brackets plated, and the oil filter boss got polished as well. A local shop called Metro Plating did the polishing. They do a lot of Harley work and boat trim. I figure I'm never going to do this again in my young life so it might as well be exactly what I want.

Those are some big $$## but if that is what you want and you are happy that is all that matters .

That looks very nice!

Pete

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FYI for everyone who mentioned N* liners...
They can't be used. They are cast into the block and are not removable without destroying them.

Thanks for clearing that up Will.

OK, the head shop called and said they ordered me new 1.50 exhaust and 1.94 intake valves that will fit the 4.9 head. The intake valve is from a 92-97 LS1 350 Chevy intake and the exhaust is from an 82-84 3.0 litre 12 valve buick exhaust. This of course is just according to the book, they will get the valves in the next day or two and try to put everything together. The valve stems are the same length on both of these as the ones on the 4.9 so there will be no change in valvetrain geometry. The only difference in lift will come from the cam, which is only .450. Also, they use different keepers, etc so I need new ones, no biggie.

After spending several hours looking at this and other 4.9 threads I have decided that my '88 GT will get a freshly built 4.9. That polished intake looks awesome.

Are there any 4.9's out here in the Arizona Dessert?

[This message has been edited by Fierotaz (edited 06-03-2005).]

Not sure how close you are but you're reasonably close to one of the best 4.9 Fiero places in the country:

Bud's Out Back
1920 E. 17th St.
Tucson, AZ 85719
520-623-8880

-Rick

quote Originally posted by Will: FYI for everyone who mentioned N* liners... They can't be used. They are cast into the block and are not removable without destroying them.

i thought if you packed the cylinder in ice that the liners could be removed?!

[This message has been edited by aaronrus (edited 06-04-2005).]

It's possible it could be made to work. The only issue with it is you couldn't use the Caddy computer because Cadillac uses a stepper motor to control the butterfly valve for proper idle. Most other TPI's use an idle air control valve which is just a stepper pintle that restricts or derestricts a hole in the TB.

-Rick

quote Originally posted by GT: .. I hate to say what I paid since I just had a run in with the wife about it, but it was slightly over $1000. The ...

Wow!! I don't care how much. It looks every dollar worth of it! Just don't forget the inside and outside of the box for that beautiful jewel

Rick: Nice project and you've really gone through the motions to make the engine good looking as well. As for pistons, another option may be to have them custom made. Companies like JE, Venolia and Ross might be able to make them in exactly the compression ratio that you want. From what I have gathered the biggest concern with the 4.9L is getting enough air into it. It sounds as though Rockcrawl has developed a better technique for porting but the valve sizes on those engines are still fairly small. I'm sure that you'll find a way around that limitation though and end up with a spectacular performing and good looking engine. What 1/4 mile ET are you shooting for?

Got my heads back. Here are some shots of the work I had done:

They installed 1.94" intake valves and unshrouded the chambers.

This is a shot through the intake ports. Nice smooth flow path. They did a bowl job here. They also removed mass from the top sides of the intake valves to allow better flow into the cylinders.

Here's a shot of the dual springs... no float here. Spring pressure and height was all checked. Spring seats were ground for proper clearance and no bind with my cam. New brass valve guides were installed and a 3 angle valve job was performed.

This is a shot of the exhaust side of the head, you can see straight through to the other side. It's kind of hard to show how much they opened up these heads with pictures.

...an image showing the size difference between the stock 1.77" intake valve and the new 1.94" intake valve. mmmmm... flow...

And finally, here's a shot of my 7 completed .040" over 4.9 sleeves with northstar pistons, N* rings, 4.9 pins, and 4.9 rods. Seven? Why only seven? Because like a retard I got over zealous on the first one I assembled and snapped the top chrome ring with the installer tool. So now I'm waiting for Cadillac Hot Rod Fabricators to send me a new top ring so I can finish my block. BTW, these rings are hella expensive and really hard to come by. NAPA is one of the few places that sell them and it's $175.00 for the set, not sold individually. So CHRFab was nice enough to offer up a single top ring for $15.00. Bud's Outback offered to send me a used one if I couldn't get it anywhere else. There's a lesson here: Chrome is brittle and expensive so be careful.

-Rick

[This message has been edited by GT (edited 06-04-2005).]