your engine building opinion please

Hi everyone. I turbo'd my saturn dohc engine. Everything worked great @ 10 psi, turned it up higher and with too much heat the engine block warped and is shot. Lost all compression in cylinder #1 and some in #2. So i've devised a plan, what are your thoughts. To buy a cheap SOHC engine for the block and rotating assembly (because sohc pistons yeild a 8.5:1 comppression where the dohc has 9.5:1). Rebuild the engine with all new bearings, rings and seals. And use my DOHC heads (overhauled), intake and fuel system. The heads have the flat faced valves so comp. would be like 8.7:1. Can anyone see any problems with this. I know the crank would have to be a 91-92 because of the crank sensor but it i got a newer engine i would just need the pcm, right?

Reply to
Carjunky
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No idea what year engines you are trying to marry up but "Lane" is probably the most knowlagable person in this group for such things.

8.5/7 would be much better for boosting than 9.5 but you should be using Forged pistons, not Hypereutectic pistons for boosted engines. So you might as well buy yourself some forged pistons that will bring your compression down. Or you could try shoehorning a supercharged 3800 and tranny in there.
Reply to
BläBlä

I would pony up the cash and throw a 3800 s/c in there (thought about it actually) but for the price i would rather throw a sbc in a fiero or somthin of the sort. Anyway since i posted i now know any 1.9l sohc or dohc will work. a 91-92 needs a 91-92 pcm. a 93 -96 needs a 93 - 96 pcm. Newer than that it is obd2 and gets more complicated. What i really need is forged H beam rods, that is the first thing that breaks and limits the saturn bottom end at 275hp. And also with the forged you would have to get the motor balanced and theres another 250 bucks. I have a lead right now on a 98 sohc engine( the block is actually stronger than all other years). I will swap in my 92 rotation assembly with new bearings and dohc heads. Then i can use my existing fuel system and pcm.If anybody disagrees with me let me know seriously. I know enough about these saturns to be dangerous. But a 400 dollar low compression build sounds pretty nice rather than going forged.

Reply to
Carjunky via CarKB.com

So does anyone know how much it should cost to get a block and head milled flat and checked for any problems? If my car ran with good oil pressure would you guys replace the pump while the engine is apart? is it o.k. to compression test an engine on a stand ( like with starter hooked up). Would you hone your own block or pay the shop? Any and all advise is good Thanks guys

Reply to
Carjunky via CarKB.com

You should find everything here:

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Reply to
marx404

I've already usedthat site to compile all my turbo info. There is nothing about my questions I have asked. has anyone in this forum ever taken apart their motor, I'm looking for assurance since i will be posting all sorts of useful threads on building powerhouse saturn motors, N/A or forced when all done with this.

Reply to
Carjunky via CarKB.com

Turbosaturns.net's forums used to be the best place to find any and all turbo-related information and experience, but they went down and disappeared about 6 months ago. :( Prior to that point, I had been reading them for several years before I started my turbo build so I can lend a few thoughts.

Several TSN posters have used the stock block for very high boost levels and I have never heard of anyone warping a Saturn block. Are you sure that's what occurred? If so, is that a heat issue? Going with an oil cooler and a upgraded radiator in the future may be good insurance.

Yes, this is exactly the route that I took. You can read about what I did in my website's projects section if you are interested (link is in my signature below). BUT, going with 10psi+ with stock pistons and rods is asking for it.

You will absolutely positively have to upgrade your fuel system. A stock PCM / injector / fpr combo won't give you the fuel you need under boost. If you ran that with your prior setup, I'd say running lean may be what grenaded your motor. You ever dyno it and monitor fuel/air mixture while under boost? That would tell you for sure.

Yes, this is good advice.

Now that is an enormous amount of work, but it would yield great results. A guy who visits my local dragstrip did this so I know it is possible.

"Carjunky via CarKB.com"

I always laugh when people use the words "throw" or "drop" when talking about a motor swap of this nature. Those who do often have never done one, because it is a LOT of time and expense. I went through one with a prior car and will never use those words. Ever. :)

'96 was the first year of OBD2 and it doesn't fit in that category. So it should be 91-92, and 93-95.

I wouldn't say that you have to. I had no plans to do so with my build and very few turbo'd Saturn owners have. It's a lot of cash for very little benefit.

I believe it is '98 and up, and not restricted to just 1998.

Oooh, this makes me cringe.

From the boost level that you've stated, plus the fact that you're building the second motor after killing the first one, I'd strongly consider upping the reliability by going with forged internals and upgrading the fuel system - or you may find the third engine build coming sooner than it should.

"Carjunky via CarKB.com"

My local shop does quick measurements for me for no charge - should not cost much from most shops.

If there is a chance that worn metal has ever gone through the pump, or your pump/timing cover has a lot of miles, then YES - I'd replace it if it were me.

I honed mine myself with a $25 tool and instructions I found on Hastings website (link is on my site).

Good luck, Lane [ lane (at) evilplastic.com ]

Reply to
Lane

There is a big difference between A: proper very expensive cylinder honing machine using lubricated and cooled precision stones to size and condition a cylinder bore. This machine is often used to increase the bore size to remove tapered cylinder wear and allow the use of oversize pistons. This is often the machine used to 'bore out' a cylinder rather than the older technique using boring bar followed by honing. B: springy, inexpensive attachment for a power drill that is more properly called a 'de-glazer'; which is a non-precision tool that is normally used to scratch a cross hatch on the cylinder wall to encourage quick ring seating. These tools come in a variety of styles some using mounted stones and others with abrasive balls on multiple springs, they do a good job when re-ringing but extensive cleanup should follow any use, and they do increase piston clearance.

A proper engine build should involve obtaining proper pistons then precision honing the cylinders to properly fit the individual pistons. This fit is often tested by measuring the force required to withdraw a feeler gauge. Anything short of this is usually a simple re-ring.

Good luck.

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