Finally got some work done on my sd4 3.3 . Had to get some epoxy removed and aluminum welded in. New valves, guides, springs ( 140 lb seat pressure, good for .700 lift ), 1.7 rockers, radius valve job, pressure tested and all surfaces straightened. Come January I'll start on the block, new rods and pistons ( 8.25 cr ).
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85 GT 3.4 14.9 @ 90 1.9 60' Old TH125/3.06 Unknown New 4T60/3.42
8.25 cr?? Why so low? Will you be adding a turbo? I have 10to1 in my SD4 and I wish I had gone higher. If I were getting new pistons I'd go to at least 10.75.
I just installed the multi-port injection I built using an Edelbrock 2-bbl intake. Still tuning the fuel table – but the engine has never been happier. (I have 11:1 CR - works out to about 10.5 at my elevation of 3500 feet)
Made some more progress. Took 4 months to get a cam made. I've had it now for 3 months. Specs are 238/243 dur @ .050, .650/.650 lift and 114 lca. My pistons and rods came in last week. Callie's 6" rods and Ross pistons yeilding 9.0 cr. Had to sink the Piston some just to get it that low. You can see the wrist pin is in the oil ring land. Had to have the head studs custom made. Arp doesn't make them any more. So far the cam was the most expensive with the head studs in second place. I've got some Piston and rod pics if someone wants to post them for me.
Big thanks to Nelson for posting pictures. The yellow 88 is what my sd4 is going into. Still have a long ways to go. Fuel management , exhaust and transmission just to get it running. Turbo and intercooler next year.
Humm goals. I'm hoping for 450hp at 7k. But will most likely turn it down to 350hp to save the transmission. Still debating on either a 4t60 or a 4t60e. Transmission builder says the e will hold up to 350hp. Should be pretty wicked with a 3.73 gear and 3k stall convertor. Just going to use it for a weekend warrior. Take it to some shows, weekend cruises and some drag strip duty. Also got some black louvers to put on the front hood and an imsa spoiler for the rear. Should be pretty sharp.
I think you will like that stall and gearing. I know its a different car and but I had that gearing in my camaro with an auto and 3k stall. Was very fun to drive and still very street-able. I believe it will all ready depend on how the convertor is built.
One more addition for the sd4.. 1 3/4" primaries and 3" collector in SS. The 555S is the gasket I had. As you can see the holes don't match.. A few more pictures. If you see any issues I may have, feel free to comment.
It appears that you have a gasket for the 801 high port head. Try a Felpro 1441 and see if that helps you out. The 1441 measures about 2-7/8 on center on the diagonal outboard exhaust port bolt holes for reference. You will need to port the gasket for your round tube header. Sorry, no pics. I have a MAC.
It appears that you have a gasket for the 801 high port head. Try a Felpro 1441 and see if that helps you out.
Here's a comparison of the difference in exhaust gaskets. The 1441 matches my SD4 PN 10038433 head's exhaust ports. The lower is a stock Duke exhaust gasket.
As Fierosound mentioned the Felpro 1441 matches Cylinder head 10038433. However looks like the OP has the 437 style head. 437 has an "inverted" bolt pattern. That gasket might work, if you put it on 'upside down'. But even if the bolts holes lined up, I don't think the exhaust ports will. I'm not sure what the correct gasket for the 437 head is.....even if its still made. 1441 is all I've seen in the last few years.
Making more progress. If you look closely at # 3 cylinder, you can see a knick on the block. THey over reved it and threw a rod, you can see where they patch the hole on the other side. The mains are steel except for #5. Got them with the crank plus 14 cams, 2x4 intake and other miscellanous parts. You can also see my mystery part installed for the oil pump. THe cam gears is the angle tooth type. Anybody care to comment on the pros and cons between it and the straight tooth kind. I noticed fierosound's has a straight type.
THe cam gears is the angle tooth type. Anybody care to comment on the pros and cons between it and the straight tooth kind. I noticed fierosound's has a straight type.
Angled teeth will be quieter. Straight cut gears produce gear whine. I'm OK with that.
Do NOT use that angled gear unless it is steel. The aluminum gear will not hold up under the power of the SD4. I know from personal experience. I switched to the straight cut steel gear and have had no problems. The engine is other wise so noisy a little extra gear noise is not even noticeable.
Thanks for the heads up edfiero. Still have some other issues I need to discuss with my builder. He likes to make fun of the sd4. Says it's in the back with the real motors. And now it's the motor from hell. LOL.
Ok, if it's an aluminum gear. What is the brand and part number for the straight steel gear set ? Won't see my builder till Monday, they're all at a pri convention in Indy. I have found a cast iron cam gear made by isky. (Used on a straight 6 )
[This message has been edited by Lilchief (edited 12-13-2019).]
Edfiero, did you do any internal damage when your cam gear broke ? Have you replaced it and if so with what ? Fierosound, thanks for the gear update. I found some in China. I'm a little leery about that. Unless they're originally made there. I've also been looking at a cloyes 2764S and a Isky 250 -TGM. Does anybody anything about either one of these ? I'm starting to think I should have put this thread in the tech section. Oh well. This engine is starting to be a pain finding parts for.
It's a cast iron cam gear/steel crank gear combo, but with angle cut gears. It will be stronger than aluminum. I'm pretty sure it's the recommended replacement for the 8-1018 set (and is all that's available now)
[This message has been edited by fierosound (edited 12-16-2019).]
Picked up my motor today. Here's some pics. Just a few things of interest . The cam has a bolt holding the sprocket on so the cover needed modified. the cam also has a roller thrust bearing. The oil pan needed modified to allow rod clearance and greater oil capacity. Small cap distributor fits nicely. Lifter cover was fabed , stock interfered with the lifters ( solid roller). Still have a long ways to go. This is not a cheap engine to build unless you have all the parts.
I had looked at balancers like that. I wanted a Fluidamper.
84-86 Duke had no harmonic balancer, only a double v-belt pulley on a hub. 87-88 Duke had a serpentine belt harmonic balancer/pulley.
Either way, the belts were tucked close to engine to line up with alternator, A/C compressor and water pump (see below) Alternator belt is installed. A/C belt would be in outer pulley grooves to line up with A/C compressor. You'll have some fab'ing to do to move accessory pulleys out to line up with pulley mounted to front of balancer you installed.
This is the balancer I have on my SD4 for double v-belts like 84 Duke pulley. GM part number 10039905
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