difference between an 83 and 87 engine

[armandodiaz]

I'm looking at an 83 engine for my 87 track car. You can read my drama in another post. I'm need to know the difference between the 2 engines. I know the 87 has a different camshaft (which is why it has 8hp more). I also know the obvious self tensioner. Aside from that is there any other differences? I might have heard the oil gallies are routed differently for better oiling. Does any know? Thanks

[JRMock]

I know first hand that the balance shafts are different... I'm sure there are a few more items...

JM

[armandodiaz]

Not too worried about those, I may even delete them (at least the belt).

I'm wondering is it possible to retro-fit a spring tensioner on the 83? I don't feel like buying a $500 guage.

[Icey1174]

Sid, Blown944 knows a lot about this stuff. He has an 83 and an 87 944. He'll prob answer.

From what I know the pistons in the 83 are forged and the pistons in the 87 are cast. I think the 83 uses the same pistons as the turbo. That's a big difference if you are looking to add some serious horse power to it. A couple things are found in different places. The fuel damper is located in the rear of the fuel rail with the fuel pressure regulator. The 87 has the damper in the front of the fuel rail.

Do you have the PET for these different model years? You can compare parts numbers and look at some basic diagrams if you do. If you don't have them I could Email them to you.

[armandodiaz]

I have PET thanks.

BTW: Let me say it, before everyone jumps down your throat, I think you ment to say connecting rods instead of pistons

[924Sman]

Difference is in the CR 9.5:1 on the early USA engine M44/02...04. Late is 9.7:1...This is established by the 4 degrees before BDC and 1 degree after BDC change on the late cam M44/05 to 12 engine models. Intake never changed on the cam. Yes a bit of upgrade to the oil pan was done on the late by means of a cross drill port or baffle change.

Early Euro engine has 10.6:1 and flat topped pistons, all others have valve slots.

Whether or not it has a spring tensioner you still need to use a gauge to check the correct tension, putting a ST on will not save you any money. Many stick or convert to the eccentric tensioner because it is EZ to manipulate and less weight. as far as retro fitting one on I do think it is possible but I am lost on one point..not certain if the block needs drilled and tapped to mount the ST to the block.?
Dal

[armandodiaz]

Thanks Sman. So if I were to do an engine swap I should keep the old cam tower, oil pan and fuel rail. Any word on the spring tensioner? Is it possible to retro fit it on to the 83?

Also, any ideas on making the bearings more reliable?

[924Sman]

Crank scrapers are said to work well. See Paragon for this item. If only looking at the 83 why not just get a late engine and be done with it? One thing is certain what ever PAG did to each model year from 83 to 88 is for the better so an early engine is going to lack the updating! Each year they made the engine just a TAD better than the previous, minimal but better none the less.

Dal

[armandodiaz]

I'd like to but I am confined to what, where and price. So far 87 engines are going for $600 while 83 are going for $300 locally.

[924Sman]

I understand but I feel you can snag a late one for close to the price range if you do enough leg work....maybe, never know! In addition to the 83 you will spend a bit more than the original cost to get it up to late spec. Now whether or not that is an additional 300, is a enigma.

You will also have 4 more years of ring wear and bore taper.
Dal

[GMingst]

Do you run PS now or manual rack. I believe I heard early early 83's had shorter cranks that will not support the PS belt on the crank. Could be BS but figured I would throw it out there...

[Eldorado]

i've got an 83 with factory power steering.

[armandodiaz]

All cranks except 16V are the same.

[ERAU944]

my father swapped out an '84 motor into his '85.5. i realize there are more differences between the '87 and '83 than the '85.5 and '83, but the only real issue he had was putting the coolant sensor into the head. he simply had to drill a bit into the head and tap it to receive the sensor, it all worked out fine. the connecting rods are forged, as stated above, and you're correct the camshaft is different (along with computer/afm). the compression ratio was the same in the US for '83-'87, but horsepower varied due to the camshaft and computer/timing changes. the CR bump was in '88, and displacement change in '89. as far as the power steering goes, you can change the mount on the engine to accept the PS, as well as adding the pulley to the crankshaft for the belt. correct also on the fuel rail issue, you'll need to retain the old fuel rail, the early is nowhere near compatible with the late.

[SoCal Driver]

As the fuel lines come into the engine compartment in a different area than the early engine, the fuel rails are different in their fuel line attachment locations. So use the fuel rail, AFS, DME, and idle control valve that is now in the car. The injectors are close to the same and the DME will adjust the difference using the O2 info.

As noted you will have to drill and tap into the coolant jacket to use the later temp gauge sender. The DME temp sender is the same.

Also the oil filler/breather has different size ports on it. Have to use the one on the engine.

Swap out the cams for more horse power. Besides the rods the pistons are beefier too. Some will cut them down for use in turbos.

[blown 944]

Agree with all stated above

However it is my understanding (and was a visual) that the pistons in the very early models are forged vs cast in the later cars.

They can use a PS pulley

Fuel lines and even the whole head assy would prolly be best retained from the later engine.

[SoCal Driver]

Think the power steering boss is part of the oil pump or balance shaft cover/casting.

[armandodiaz]

I was also told the oil gallies in the block are different on the later engines. There by producnig better oiling. Has anyone else heard of this?

[SoCal Driver]

If you need an engine yesterday one takes what one finds. If you are looking to build a race engine the pistons and rods from the early engines are preferred.