Ok. I've gotten the motor out of my 88 Iroc (305 TPI) and I'm about to put in the new 350. It's an 84' block with Chevy 882 heads. So far everything seems ok except for an AC bracket hole that doesn't exist on the new heads (never meant for AC I guess) and no hole seems to exist for the knock sensor. How can I get around this knock sensor problem? Also, what else can I expect to discover as I start putting this back together? Is the car going to run with the computer from the 305? I just paid 300 for a new ECU for the 305 , I hope I can still use it.

Thanks guys. I know I'm brand new to the board, but I promise I'll introduce myself better and post some pics when this is all done (sooner than later I hope!)

All help apreciated

 

The knock sensor hole has been around since 1955; they just didn't realize back then that it was the knock sensor hole. They figured out that that's what it was in about 81.

Take the pass side coolant drain plug out of the block. The plug is hiding the hole.

About all I can think of that you'll discover, is that it will probably be slower than your 305 was. But if your 305 was blown up or something, maybe it will be an improvement.

 

Yeah.... the coolant drain plug on the cylinder head that isn't utilizing the temperature gauge should do the trick. In fact, it'll be a much more accurate knock sensor location because it's closer to the combustion chamber.

As for the AC bracket... if I were you (and I know it'll be time consuming), I would take off the heads of the 350 (they 'should' be inspected anyway, and a fresh set of head gaskets will help if you want it to last), and check the valve size.

If the valves are no bigger than you're stock 305 (and I'm going to guess that they aren't), then just use you're stock 305 heads.... just give them a nice three angle valve job to aid in air flow. This will solve you're problem of the AC bracket, as well as making sure that the 350's cylinder walls aren't really bad....

Good Luck!

 

Cra Z Canuck, Being A Fellow Canuck, I Say Hang In There. I Do Have 3 Fcars, A 1982 Camaro, 1984 Firebird And 1986 TransAm. I Put A 400 Into The 1982 And It Now Has A TPI (Runs Great), The 1984 Had A 305 Carb, Now Its A 350 TPI (Runs Great) and I Recently Swapped The 1986 305 With A 350 (Runs Great Too). You Will Be Thrilled At How Well Your Car Will Run When Your Done.

 

your goign to have to reprogram the computer but it will work. jump on the PROM burning boards and ask there they will know more then i

i myself hate EFI

 

How long did it take you to get the 305 out? I'm planning on doing a swap to a 350 TPI in my 86' this winter sometime.

 

it about time someone else has some Memphis audio **** in their car

 

Yeah I like the Memphis subs. Best thing next to /////Alpine IMO.

 

i'm putting 3 memphis HP 12's in my car and two 1000D's :-D

 

Thanks for all your input guys. We did find the hole for the knock sensor and it worked but then...TRAGEDY!!...

On monday night we finally got all the accesories on the motor, plus the distributor, all the harnesses etc. It was a bit tough to get started and running, but after playing with the timing and the idle screw a bit it was running AWESOME. Even with the 305's ecu, the ****ty old exhaust manifold, no fuel pressure regulator or bigger injectors and no real science in tuning the timing - it still ran awesome and sounded even better. I shook my mechanic's hand, and with the biggest smile in the world on my face I left for the 15 minute highway drive home.

5 minutes away from my mechanics house my oil pressure started to drop. I watched with great concern as it went from 400 (Max) to 200 and then to 100. By the time I got to within a few minutes of my house, the pressure was dropping right to 0 every time I came to a stop. And by the time I got home I could hear knocking noises from the bottom end. (noises I was very familiar with - a worn out, knocking bottom end was the reason I had to replace the motor in the first place!)

Tuesday morning I started it up and oil pressure was 400 again, and no noises, so I decided to chance the 6 minute drive to work (an Acura dealership) where my mechanic also works. As I drove there, I watched the oil pressure drop in exact proportion to the engine temp. rising. By the time I finished the 6 minute drive, my oil pressure was gone again and the knocking was back.

I can only assume this is a bearing problem. No other problem would affect oil pressure in the same way - is there? I would love to find out it was a problem that didn't require me to pull the same f$%#$ engine out that we just spent 2 weeks putting in!!

Any thoughts? Sympathetic comments?

 

O.K., I know that last post was kinda long - maybe that's why no one answered it ...the question hidden within it was - Are there any other problems besides bearings that could cause the loss of oil pressure like I described? Can you check clearances on all main and rod bearings while the motor is still in the car? Since the motor started knocking because I had no pressure, does that mean I've already F#@C@D my crank up, even though it only knocked a little and only for a minute or 2?

Thanks

 

I think that you can pull the pan and pull all the caps one at a time individually, and look at the bearings. I have never done it, so do it at ur own risk. You could have a bad oil pump, is it new or stock one? I would say that you just blew the lower end, and will have to more than likely put all new bearings in. Once there's a knock, you have something wrong.

In my 305 I had a knock in the lower end of the car from running it low on oil well I ran it for 3 months with the knock, and I eventually got it to go away by messing with my timing. But just 2 weeks ago I heard the knock come back, but not as bad as it used to be. Ignoring it again I filled the oil back up and was letting it idle b4 I went to work. Hopped into the car and as I slamed the door, clunk knock knock knock....dead! The kockin wasnt very violent but when I pulled the upper plenum to get access to my kick down cable. I found chunks of aluminum and piston ring in my upper plenum wooo. So I'm really curious what the hell went flyin!

 

Clogged oil pump

You could, but you would get a more accurate check by removing the engine.

If you had an adequate oil level the entire time.... then I doubt you're crank got damaged. If you're oil pump is clogged, then you're camshaft is more than likely the culprit here.

If it's only knocking for a minute or two (during warm up), it might be the oil you're using.

 

I would love it to just be the oil pump - but I can't think how the pump being clogged would let the pressure be high at startup like it is...but I'm not too familiar with the internals of an oil pump....

ok thats good to know..at least it's a start... If we can identify a bad bearing right away we could replace it without pulling the motor I hope....

I've been told that even a hairline scratch on the crank journal or bearing surface can cause problems - or at least premature wear. I have to think that any amount of knocking would be enough to mark the surface...I guess we'll see soon enough - my mechanic says we'll open it up this Saturday.

Actually it only knocks after warm up... I'm using 10W30, but I was planning on switching over to synthetic right away

btw I'm not arguing with you on any of these points I'm just playing devil's advocate..believe me, I hope you're right. But the pessimist in me has to believe it's the worst case scenario - toasted bearings and a crank that needs to be remachined.

 

This greatly depends on just how much 'crud' is built up in the oil pan. When you obtained the new motor, did you take off the pan.... and see how the old oil looked before you installed it?

The only way the cam doesn't get any oil, is if the pump isn't doing it's job.... or there isn't enough oil in the pan for the pick up to pick it up.

Of course, but this would be a constant knock. When I spun a bearing a few years ago, the engine knocked during warm up, when it was warm.... and when I drove (it was constant).

I did not take you're post as a challenge, as we're all here for one main reason.... to share whatever we've encountered with our cars through experience.

If it's you're crank, it will be a constant 'knocking' in rythme.... which will increase with RPM. If it's not in rythme, and it's sporadic, then it's you're timing. If it sounds like a constant metal-to-metal (echo type) sound, it's you're camshaft.