Engine and Transmission Tech

More pictures of 4.9 V8, gray one with modified oil pan a Porsche 924 swap,red one and black one Fiero swaps. There was a guy on the MGB Experience board that was doing a 4.5 swap.The archive pictures were lost when it was upgraded.This engine weighs 360lbs. You would have to make custom headers ,but should fit in there.It can be carbed and use a modified Olds 75-80 distributor. Pennocks Fiero site has lots of info on rebuilding and upgrading.Also Fiero Addiction site.







Edited 2 time(s). Last edit at 12/27/2009 03:04AM by mgb260.

The black one and rockers modified with newer Buick V6 roller trunions, these engines are already roller cammed and use 60 degree V6 bellhousing, use redrilled GM FWD 3100 V6 flywheel.More pictures of the red one on the flanged liner thread:





Edited 5 time(s). Last edit at 06/14/2010 08:04PM by mgb260.

Jim, Thanks for pic's and info.Norstar heads work on this block? I believe Norstar block has alum. bore? 4.9 may have more bore potential. Bore spacing, just measure with calipers/steel scale? Happy Holidays,roverman.

Roverman, I don't presently have one but will pick one up after the holidays to play with. I think it would be worth seeing if someone can cast aluminum heads to replace the stock ones. Stock valves are 1.77 intake and 1.50 exhaust.People have put 1.94 intakes in but, in my opinion is a waste of time unless valves are unshrouded.Stock HP was around 200HP, but with Delta cams regrind closer to 280HP.Wide Torque band from 2000RPM to 4000RPM around 300+ft lbs. The max bore of .040(Northstar pistons) also raise compression about a point to 10.5. Quad 4 pistons lower compression to 8.5 for Turbo. I think you would be on your own with Northstar or Quad 4 head swap. The rod length of the 90 4.5 was longer than the 4.9(5.9 vs 5.7) I think with shorter compression height pistons, that would be a good swap for the 4.9. I think compression height stock is 1.25.Maybe Quad 4 pistons with the longer rods .



Edited 4 time(s). Last edit at 10/17/2010 02:03AM by mgb260.

Those engines have a horrid reputation for internal cooling system leaks. I personally know 4 people who have had them go tango uniform because of this. The factory installed stop leak on the assembly line for goodness sake. It 'aint a Northstar!



Edited 1 time(s). Last edit at 12/24/2009 06:36PM by Dave.

I think you are talking about the earlier 4100HT,maybe early 4.5 TBI. They were terrible! 80's 4.5 intake would be good for carb swap,no injector holes to plug. 90 and up have had less problems with cooling than Northstars.The 90-92 4.5 and 91-94 4.9 use much improved gasket/sealing materials. My brother is a GM mechanic and he said there have been problems with aftermarket parts store water pumps(use GM delco) If you go to Pennocks Fiero Forum do a search in the archives. The trick is to rebuild with Permetex Hylomar HPF on the O rings for the sleeves.There are quite a few holding up to 300+ HP.




Edited 3 time(s). Last edit at 12/24/2009 07:43PM by mgb260.

Jim, Regarding the Northstar, You've read the Wikipedia data? I don't no how reliable that is but you may want to consider a 2003-up crank(forged)? 4" bore centers, crank swap? 4.4L best for boosting and VVT. I heard a lot of, "negative" in buggy use, regarding over-heating fragility. The Aurora 4L. should be best for hi- boost,(thickest liners), used in the Shelby I series. Good Luck, roverman.



Edited 1 time(s). Last edit at 12/28/2009 06:46PM by roverman.

Are they seriously 4" bore centers? WOW that must be a small V8.

Nic, even worse, it's "square". Wikipedia-check it out. Nic,You could be the ,"first" to build a 4" bore Northstar. We would "marvel" at your freedom of sharing, Un-like, "SOME", we know.roverman.

I don't know how this thread morphed,different manifolds use different valve covers,TBI vs Port injection,both transverse manifolds. Also note main caps same height as block for easy girdle!Some more 4.9 pics:






Edited 2 time(s). Last edit at 12/31/2009 01:41AM by mgb260.

100mm (3.938") bore centers. It's got to be a short engine. I've found one reference for 360lbs., says with flexplate and alternator. Not bad. I wonder what the overall dimensions are.

Jim, are those pix yours? Or do you have one of these laying around? Put a tape to it if you do. Let us know how long the block is and maybe block with waterpump. Deckheight? Width? How about width with the Quad4 heads. Cool.

What is up with Cadillac and integrating the valve cover flanges in with the intake. Very limiting. I suppose "very limiting" is the challenge with these engines. I get it.



Edited 1 time(s). Last edit at 12/29/2009 11:13AM by NixVegaGT.

Nic, It is common for the intake and heads to share valve covers. GM 60 degree V6, Ford FE 390-428 etc. It might be to save weight with a smaller iron head? I was just showing that the early TBI 4.1/4.5 use a straight valve cover. Also they have a conventional front water outlet on the RWD engines. The 4.9 is not my engine, just thinking of a future project. They are all over in wrecking yards for $300. I know very little about the Northstar. I know it is compact,short and maxed out on bore. It has nothing in common with the 4.1/4.5/4.9 family.You guys were just dazzeled by those DOHC heads! Actually, I was just thinking cheap light motor,300HP in a MGB that would be an alternative to the GM V6.Similar to the 215/Rover in size.I did find some weights:36lb each for iron heads,45lb for block,350lb for entire engine. You could go pretty big bore if the head bolt bosses allow the room.. If you go 4" I still don't think the cylinders would touch.Custom stepped sleeves and aluminum block bored to fit.The 4.9 in the picture is already bored out to 3.66" bore(.040 over stock) about 3/8" wall and 1/2" between cylinders.I'm guessing 4.36" bore centers. Here are comparison pics between Northstar and 4.9.





Edited 7 time(s). Last edit at 02/10/2010 11:57PM by mgb260.

OK so the bore centers are more than 4". Makes more sense now. Thanks man.

Ok, so 3.62" std. bore +.5" between bores, I think that + 4.12" bore centers?

Is the orange block the northstar? What is the bore again on that motor? Looks like quite a lot of room between cylinders on that one.

Jim

Jim, No, the one with the siamesed bores is northstar. The orange one is the 4.9. 3.62 stock bore with thick wet sleeves.



Edited 1 time(s). Last edit at 12/31/2009 01:41PM by mgb260.

Roverman ,you forgot the thickness of the top part of the wet liners. I haven't got one to measure yet,just guessing. I think Nic is still confusing the Northstar and 4.9. The pictures above show Northstar has siamesed bores, the 4.9 large space between wet liners. Here is a picture with head gaskets showing a lot of room. I would be happy with 3.8 bore. I don't remember the formula for boreXstroke= cubic inches.3.62X3.62 =4.9=300 cubic inches. So, 3.8X3.62 and 4X3.62= how many cubic inches?

Probably. There isn't a ton of clear info about them online.

3.8 bore x 3.62 stroke: 5.4l (329 ci)
4 bore x 3.62 stroke: almost 6.0l (364 ci)

Are you going to build one of these, Jim?

Probably not but it is tempting. Might consider it after the RD goes back together so maybe mid summer at the earliest. But I'm confused about the bore sizes of the 3.9 and the northstar.

BTW, the formula is 8 pies stroked times square radius. (That is right, right?)

Jim