mlbinseattle

The oil pan on my 305 HO has a dent ... more like a curved crease like it was hit by a small diameter pipe ... on the front of the oil pan near the front seal. Don't ask me how it happened. lol. Anyway, the crank is now hitting the creased area while running and making this nasty tapping sound. I want to drop the oil pan, beat the crease out, and re-install it.

I've done this before but never on this type engine. Usually, it's a matter of undoing the motor mounts, transmission mount, transmission linkage, and any lines that are secured, and then jacking the engine up a few inches so the oil pan will clear the crankshaft.

Question: Has anyone done this on this type engine, before? Is there anything that I need to be aware of besides what I've listed? I don't want to create a disaster while doing this. Any help is appreciated.

sofakingdom

iTrader: (1)

It is QUITE difficult to get the pan out and back in, and sealed up right, in the car. The fit of the motor to the chassis is VERY tight in these cars.

You will get done quicker, FAR less trouble, and FAR more likely to get it leak-free THE FIRST TIME, if you just face the issue head-on, don't try to get out of doing the work that has to be done, and pull the motor. Doesn't have to come all the way out; mainly, you'll need to undo the motor mount through-bolts, take out the trans mount, drain the water and remove the rad hoses, pull out the rad, unhook the trans cooler lines if it's an auto, remove the dist cap, unhook the exhaust from the manifolds, hook up your cherry picker, and lift the motor while pulling it forward. It will need to come up about 6 - 8" and forward about 3" or so.

Notice that EVERY SINGLE THING you have to do in order to do it THIS way, you'd have to do if you were going to try to fight it with jacks and 2x4s and all that, EXCEPT that you'll be using a cherry picker instead of all that. AND, it'll take you about a quarter the time, cause about a tenth of the trouble, and you won't risk tearing up even more stuff.

Otherwise you will find yourself doing twice as much work as the work you're trying to get out of doing, trying to get out of doing the work. AND producing an inferior end product besides. A lose-lose proposition.

mlbinseattle

Thanks for the reply, and I was afraid of hearing that. I figured that I'd need to pull the engine up and forward. Looking at it, I was thinking that it had to be a very tight fit, engine to chassis. I was also thinking that the distributor would need to get pulled.

On the bright side (yes, there is one), this will give me an excuse to do some other needed things. The car had been sitting for 12 years, and I recently revived it. I've done all the obvious things, but there's more that's needed. Pulling the engine up and forward will give me the opportunity to change out the exhaust flange gaskets. I'm certain I have an exhaust leak on the driver's side, and that is where it's happening. I wasn't real thrilled about doing this, but I know that, one day, I'd need to do it. Also, I need to replace all the hoses and the anti-freeze, anyway. There is also some surface rust on the firewall next to where the heater hoses connect to the heater core. This will give me a chance to take care of that, too.

I assume that the drive shaft will need to get disconnected from the rear end at the U-joint, too. Am I correct assuming this? Or is it okay just to leave it connected? I don't want the drive shaft yoke coming out of the end of the transmission only to have transmission fluid leak everywhere.

rusty vango

just separate the trans from the engine and leave it there. less work quicker turn around too.

Joe Tag

iTrader: (4)

No way in hell it's easier or less time consuming to separate the engine from the trans. Explain your reasoning why you think so. 4 easy access bolts on the DS 4 easy access bolts on the cross member, shifter cable and one nut on the trans mount that you really don't even have to take loose. Versus the whole idea of separating and realigning the engine trans combo. The only reason to do it is if he wanted to take the opportunity to change the front seal on the transmission.

rusty vango

I use guide pins to re align the engine to the trans. makes it a snap to mate them. I just find it easier to leave the trans alone and just remove the engine. it keeps my work all in one area. (or im getting old and lazy!)

gt4373

The GM Shop Manual Makes It Sound So Easy

Joe Tag

iTrader: (4)

We can call this a difference in technique or preference. I'm telling you though, you're working harder than you have to. If the engine had to come out of the car I would entertain the idea, but he's just doing a pan change.

rusty vango

I find it easier to just R&R the engine. it makes it easier to get a "once and done " leak free job. plus im not under the car trying to wrestle with it.

Lurbie

iTrader: (3)

I'm not looking to get an argument going, but I'll tell you it can be done without removing the engine, as I have done it myself for a similar reason, except my dent was pointing outward (the pickup fell off and took a few laps around the crank). You pull the motor mount bolts, distributor cap, and raise the engine. Do a little wiggling and the pan will come out. Buy the one piece Fel-Pro oil pan gasket and it goes back together just as "easy." I'd encourage you to use a cherry picker to lift the front of the engine up (jacking on the balancer is not suggested).

Having said that, if time isn't rushing you, I'd unbolt a few other items and raise the engine more effectively as some of the other guys have suggested.

edit to add:
The one piece Fel Pro gasket comes with 4 plastic install tools. Basically slip on bolts that hold the pan in place for you, allowing you to start and torque all the bolts the right way. I had no leaks using this gasket.

OrangeBird

iTrader: (1)

I think both methods have merit depending on the circumstances . In Rusty's instance , Since you've got the engine separated anyway , may just be a great time to pop in a new rear main seal and maybe even a torque converter seal in the transmission pump as well . In Joe's instance , if one was SURE it was only the pan leaking and no further gaskets and seals were needed , it would be quicker to not split it and just hoist the whole thing up enough to get at the pan .

Bottom line is that all 5 respondents have given great advice ;

plan on lifting it at least high enough to get the access to get the fit right in one try

And it goes without saying to make DAMNED sure ya got it trussed up good and secure before ya go getting underneath it !

Joe Tag

iTrader: (4)

I'll point out it's an 84 so it should have a 2 piece rear main seal. So he should only have to separate for the TC seal as I said before. Just seems like an awful lot of extra work when he never said he had any leaks.

mlbinseattle

There were never any leaks to begin with, and the transmission had been rebuilt prior to getting parked. Other than road film on the bottom of the tran pan, I haven't noticed any transmission fluid dripping out of the front seal area on the tran. Also, there were no oil leaks on the engine. I've been driving this thing for almost a week now, and everything looks, sounds good. I know seals, especially front seals on a tran, have a tendency to dry out over time, and getting down/punching the engine too often can cause one of those to blow. I'm on the fence at this point if I should just bite the bullet and replace that seal, anyway. I really don't want to as I'd have to drain/yank the torque converter and then fill it fluid, again. After driving it a bit and seeing that nothing is happening at this point, I don't see the need to replace that seal. Having said that, I think I'll go with Joe's plan of just leaving the engine connected to the tran. Then again, I have a few weeks before I intend to tackle this endeavor, so I might change my mind and do it, anyway. I guess my concern here is this: I don't intend to yank the engine completely out ... just high enough to drop the oil pan. If I did decide to split the engine from the tran to replace the tran front seal, would there be enough room to yank out the torque converter? If not, then I'm not going to screw with it. (Yes, I am old and getting older.)

There are no engine oil leaks, and the rear main seal seems okay. I don't intend to do anything with that.

I cranked it up, today, and crawled up under engine where the dent is. I noticed some oil beginning to form where the dent is, so I'm thinking the pan suffered a hairpin crack. I'll just go ahead and buy a new pan instead of attempting to weld the old pan. Less work and less worry, afterwards.

Everyone here gave great suggestions, and I do appreciate all the replies. One question, is it really necessary to unmount the starter from the block and let it hang like the OEM procedure stated? I was just hoping to disconnect the wiring from the starter.

Also, is it really necessary to move the engine forward after it has been lifted? I'm just wondering because it seems the pan will drop from the rear, anyway. Thoughts?

Joe Tag

iTrader: (4)

Starter has to come loose for access to the pan bolts. Have to bring the engine forward to be able to raise it high enough. No need to drain the TC if you go that route, it will stay full. Make sure you have a hoist with a long boom on it. The bumper on these cars is a problem with clearance. Not a fun job any way you go.

Lurbie

iTrader: (3)

Starter and distributor cap have to come off, y-pipe too if you still have that, I did not disconnect the trans mount, but the trans (700r4) bellhousing was touching the firewall, had I raised the engine anymore, I would have been lifting the entire car. The pan does just squeeze out from the back.

mlbinseattle

@Joe: I understand what you mean about being able to get it high enough. I do have an excellent engine hoist with a long reach. Also, I had just replaced that starter, too, so I am well versed on removing it. THAT was an experience. First time I ever dealt with a starter that had a shim, and there is hardly any clearance down there to work. lol.

@Lurbie: Yes, I still have the y-pipe. I had planned on changing out the flange gaskets where it connects to the exhaust manifolds, anyway, before the dent in the pan occurred.

Also, it sounds like I won't need to disconnect the drive shaft U-bolt at the rear end. It sounds like the engine doesn't need to come that far forward to get it high enough without worrying about the yoke coming out of the end of the tran. Is my thinking correct on this, or should I go ahead and disconnect the U-bolt at the rear-end just to be on the safe side?

Lurbie

iTrader: (3)

I did not unbolt my drive shaft.

mlbinseattle

Thanks.

Another question. What about exhaust donuts between the y-pipe and exhaust manifold? I assume these are needed, but I haven't been able to find a place that sells these for an '84 Z28 305 HO. Do these even exist exist for this engine, and if so, where do I find these?

sofakingdom

iTrader: (1)

No they do not; the pipes have flanges that seal without them.

8Mike9

Read through this thread...am I correct that the engine is going to stay in the car, but be pulled forward enough to raise it higher?

If so, I think better than (and what I do when I pull an engine with an Auto) is take the TC bolts off the flex plate first. little more effort, but ensure no binding and possible damage...plus, easier to put the engine is without trying to align the splines.

OrangeBird

iTrader: (1)

If one is separating the engine from the transmission this is the only practical way of doing this . I never , EVER , take bellhousing bolts out till the torque converter is unbolted . It is a near certainty that the transmission pump will be destroyed by attempts to shove the engine with torque converter attached into the front of the transmission .

Joe Tag

iTrader: (4)

No, if it has to be moved forward it would be with the trans still attached. If he separates the two there is no other way than to unbolt the flexplate from the TC. If you didn't, and by some miracle you could align the pump with the TC, you would surely tear up the seal.

mlbinseattle

If the engine remains bolted to the tran and the entire unit is lifted and pulled forward, how would that possibly cause a bind?

Edited: Never mind. I apparently didn't see the following responses to your post. I agree that, if the engine was separated from the tran, then yes, I would remove the TC nuts and leave the TC in place. Trying to stab the engine to the tran with the TC still bolted to the flywheel would cause possible damage. My first thought would be the front tran seal would get damaged.

mlbinseattle

Thanks. I had been wondering about that. So, if there's an exhaust leak in that area, chances are it's coming from the exhaust manifold ... probably a bad manifold gasket.

8Mike9

Sorry, I got a little lost in reading through...one post mentioning that the tranny/engine was separated, another mentioning no fluid would leak from the TC...my assumption was incorrect on what was actually happening.

Old SNL...Never Mind

mlbinseattle

Okay, guys, one last question before I get started with this endeavor. There are two round, steel tabs with holes. One is bolted to the intake next to the #1 port, and the other is bolted on the intake rear of the #8 port and next to the passenger side of the distributor. I attached a pic of the one located in the front next to #1.

I assume these are used to attach the chain when lifting the engine. Am I correct to assume this? Usually, I've removed a couple of intake bolts with other engines and used spare bolts to attach the chain. (This is the first Chevy that I've dealt with.)

The plan is to use an all-thread stud with nuts, approx 21" long, to spread the chain above the carb. This will prevent me from needing to remove the carb which is one less thing to worry about.

Lurbie

iTrader: (3)

The pic you show is an engine lift bracket. I am struggling to picture what you're planning to do with all thread, but I'd never use all thread to lift an engine, that stuff bends way to easy.

mlbinseattle

Thanks. I couldn't remember what those things were called. So, I was correct to assume that those were used to lift the engine. That's excellent. Makes it real easy to attach the chain without taking out any intake bolts.

Like I stated, previously, I'm going to use the all-thread as a spreader. I'm going to spread the chain above the carb so the chain doesn't come in contact with the carb. In essence, the chain at each end will rise vertically up to the all-thread which will be higher than the carb. Instead of using a beam as a spreader (see pic), I'm going to use all-thread so I can attach some nuts on each side of the chain to anchor the all-thread. There are many different diameters of all-thread. I'm certain that a 3/4" or 1" diameter all-thread isn't going to bend too easy. And if it does, I'll weld two pieces together and leave enough thread on each end of one to go through the chain.

There's more than one way to skin a cat.

TTOP350

iTrader: (8)

Wow, I just R&R'd a pan on a 92 TA vert in less than 2hrs. Easy peazy lemon squeezy

Lurbie

iTrader: (3)

OK, I see what you're doing. Just be careful doing it, That's gonna be a bigass chain link to be able to put a 3/4"-1" bolt in the middle of it. But where there's a will, there's a way.

Joe Tag

iTrader: (4)

You can use smaller all thread through a piece of thick walled 1" gas or water pipe for a spreader maybe and accomplish what you want. It should hold without bending.

rusty vango

I have seen this ,with some pretty grim results. I wouldn't use all thread on anything I give a crap about.

Joe Tag

iTrader: (4)

Not going to be lifting on the all thread or the pipe, it's just to hold the pipe in the links where the chain is spread apart. Just a spreader, not a lift point. Tighten the nuts down to hold the chain against the pipe and it won't go anywhere. It would be a compression force. Cylinders are strong in that manner.

mlbinseattle

The allthread inside the pipe is a great idea. Thanks for mentioning it!

mlbinseattle

Thought I'd give you guys an update. I took my time performing this task as it's been a week since my last post.

Sofakingdom, you weren't kidding about how far up and out that engine had to come. Even then, I had to place a floor jack under the transmission mount and jack up the transmission as far as it would go ... right up against the underside of the body. The pulley on the harmonic balancer was right where the top front part of the radiator would sit if it were still in there. If I had gone any further, I could had just pulled the entire drivetrain right on out. lol.

The pan actually dropped through the forward part of the engine. I pulled it forward, turned it 90 degrees, and flipped it on its side. Came out between the bar where the tie rod ends connect and the front stabilizer bar. Of course, there was some fanagling the occurred getting it out and back in. All in all, it wasn't too bad.

Lurbie, thanks for the tip about the Fel Pro gasket. It was a snap and assembly was easy. No sealants were necessary.

Finally, I made a spreader out of a piece of 1/2" pipe, 1/8" wall thickness, 19" long. I welded two bolts and two washers at each end (boltheads inside the pipe, threaded end sticking out of the pipe and washers, and washers were against and welded along with the bolts to the pipe) to go though the chain. This thing was solid. I had it connected and then realized that I didn't need it, after all. The chain never made contact with the carb. And I didn't need to remove the hood. If I had used the spreader, the hood would have needed to come off. Oh well, live and learn.

All in all, things turned out, nicely, but I don't want to do it again anytime soon.

You guys were a great help. All comments were greatly appreciated. Thanks for all the help!