Is it possible to convert an early mark IV big block to a one piece rear main seal? I want to know why it's not possible, or if it is possible by machining the block.

 

It's been the while since I've seen the back of a BBC, but I don't think there's any material there to machine.

 

Can't be done that I'm aware of. Small blocks you can buy an adapter to put a 2 piece RMS crank into a 1 piece RMS block, but I don't believe any such adapter exists for a big block.

 

See there is a conversion kit for the BBC's for the 1 RMS to 2 RMS, (search Stefs) but nothing in regards to the 2 RMS to 1 RMS. Hmm.. dang Looks like I am stuck ordering a crate 502 or something.. sigh.

 

I've never really understood the difference. Always figured it was just how they made the gaskets lol

 

No it is not possible.

Which is of course why there's no "kit" available to do it.

There's no real reason to do it, besides. The reason there's "kits" available to go the OTHER way, is people have all these high-perf cranks laying around from all these years gone by, that won't fit in a new block; so they make the "kits" to do that swap, which is at least possible. The opposite situation doesn't really exist.

What are you REALLY trying to accomplish? More than likely, there's some other BETTER answer available to get you where you want to go.

Start at the ultimate goal, and work backwards, and you may find that some individual thing you've got yourself all wrapped around the axle about, can be dispensed with altogether, by merely taking some other approach. Don't get all focused on killing alligators and forget that you're really trying to drain the swamp (at which point they'd all leave ANYWAY,) let alone that you're REALLY doing all that in the first place because you're trying to build a building where the swamp is. Make the end result your priority, not some perceived "necessary" step in the process. The main thing is to keep the main thing the main thing, and not get distracted down some left turn into the weeds somewhere.

 

This is why I never come here anymore. Assuming people never do their research.

I don't need to lay out my plan for you because it is irrelevant, all I want is my questions answered.

However if you must know, I was trying to turn a Mark IV into a Mark V/VI so I did not have to buy a crate engine as the Mark V/VI is extremely hard to find in my area at salvage.

Convert a 2 RMS to a 1-RMS, then slap a 1-RMS to 2 RMS adapter into the block to use the old cranks again. However since its apparently not possible to do, this is out of the question.

Saying there's no real reason to do this shows how immature you are, as you fully assumed I had no motive to do this.

You really sound like an arrogant ******* who tries to sound smart, but actually isn't.

God this board sucks and I am out of here again.

 

This is why I rarely ever come here any more... people who don't know what they're doing, cook up some hare-brained scheme that won't work, and then get all juvenile and up in a snit over being told the truth. Yeah I know the truth sux sometimes, but it doesn't care whether you like it or not; it remains true.

So in a further attempt to be helpful and informative:

The question that needs to be answered FIRST is NOT, how to turn a Mark IV into a Mark V/VI; it's, why a Mark V/VI in the first place? Come down off your little-kid attitude about being told that your initial proposal won't work, and tell us what you're REALLY doing, and maybe those of us who KNOW HOW TO DO THINGS can help you. So the question for you now is, what are you REALLY trying to accomplish? What's the "end game"? We've worked our way back from killing the alligators (putting the new crank into the old block) back partway toward draining the swamp (turning a M4 into a M5/6) although we're really not even quite all that wy yet, but we still don't know what the PURPOSE is, and therefore we still can't help you get there.

 

My first post already implies it won't work, I came in full well knowing what I would hear. But there is talk on the Ford boards of machine work that could be done on their blocks. This is the only board I come to that deals with older blocks and I thought I could get toss a simple question out and see if anyone had heard of it being done to the chevy blocks.

Now.

The benefit of doing this, is being able to run the Gen V/VI oil pan and crank sensor timing cover. This allows for a 24x cam sync to be sent to a fake dizzy that sends it to an LS1 PCM.

Yes, I am converting a BBC to run off a LS1 PCM with an injector manifold in the regular BBC firing order.

 

OK, that makes sense.

Now that we know where you're going, we can help you get there, by some other means.

Try these guys here. http://www.eficonnection.com/eficonnection/58x.aspx Don't know if they have exactly what you're looking for but can probably point you down a path.

This board has very little BBC knowledge on it. Only a few of us here have any experience with them. Since these cars never came with them, this isn't really the place.

Try here http://www.chevelles.com/forums/forumdisplay.php?f=13 for more people who deal with big blocks.

 

Yes, I have been there numerous times and they have given me a lot of inspiration. He posted the 502 ram jet running off the PCM on LS1tech and thats what got me interested.

With a mark V and VI block, everything works. I have a complete running engine "built" on paper. The only difficult part is making sure the injectors I switch are on the correct bank in the computer, as it's a lot easier to just rewire the harness and swap the injector plug sides than to reprogram the PC.

The whole deal is I can cut my costs by half with a mark IV block, there are no cheap Mark VI blocks in my area at (if they are ever here) all which means I have to get short block crate, and I am nervous about using a Mark V and the special gaskets.

Thanks for the link, I want to know why it's not possible. I may be only 22, but I have been told too many times already in my life something isn't possible, only to try it and succeed.

I wonder if frankensteining a Mark V and mark IV oil pan together would work.

 

Because if the BBC is the same as the SBC the rear of the block is cast different to mount the 1 pce seal adapter ( or the 1 - 2 pce conversion adapter).There is nothing there to rework on a 2 pce seal block

Once again considering the differences in the SBC , it would appear be the better option.
All you would need is the front pan section that seals to the later timing cover grafted on to a early pan ?

 

That's what I wanted to hear.

vetteoz: The only thing I can think of preventing this is if the top of the pan is different for how the seals are. If there's no difference, there's no real problem..

Are the SBC oil pans different?

 

On a SBC ( and BBC appear to use same arrangement ) ;all timing covers fit all engines regardless of crank/ block type so reasonable to assume front pan section/ seal is identical
( 2 pce used 4 seperate pan gaskets ; 1 pce engines have single pan gasket but aftermarket 1 pce gaskets
available to suit 2 pce seal engines )

Rear pan seal on 2 pce crank is fitted in the groove of rear main cap
(MARK IV shown )



1pce blocks do not have the groove in the rear cap




On a 1 pce crank, the rear pan seal fits into the adapter that holds the crank seal.






So on that basis unless there are differences in the BBC timing covers ,you could use a late timing cover with pan to suit early block?

 

Any reason it just HAS to be a big block? Big block has a lot of excess baggage with it in a third gen due to the size, weight, etc.

Better bet would be a 383 or a 400.

FWIW, ive done the SFI conversion using one of the TPIS timing chain covers on my pre-86 block, and their (EFI's) wire harness. Has a retro roller conversion as well. The parts from them are second to none, and fit very nicely. But, as with anythin nice, you have to pay to play. The EFI conversion gets real expensive real fast. The system itself (induction and wire harness) will cost at least $1600. Its worth it for the drivability and the fact that you dont have to mess with it once its tuned, but it is a pricey conversion.

If your adding a big block, which is a bit too much for a street driven third gen IMO, the costs will be even more. Both a small block and big block will require some of the same things: everything in the driveline on an RS will need to go, and the car will need SFCs and other stuff to re-enforce the body so the engine doesnt tear it apart. The most that is reusable is the trans, which will need to be built up, and the rear end. On top of that with a big block youll need new front springs, special headers, etc. to handle an engine thats heavier and larger than a small block.

Theres a lot more to this than just plunking the engine in. With a stock RS, theres little in the exhaust or driveline that can be used. Essentially it all has to go. At this point for cost considerations, figure that you have a rolling chassis with nothing in it but a rear end that might be usable with a new posi carrier and gears, and a transmission core. Everything else will need to be bought.

 

As for the conversion, with a small block, its relatively straight forward, but theres a lot that needs to be done, both wiring and fuel system wise to make it all go. I collected the peices to make it work over a few years. Dont even know what it cost to do it, but Id imagine it was at least a couple of grand. If you use an older 4x vortec style setup, it will be a little easier as you can use a standard throttle and the vortec dist. The '411 PCM can do both DIS and 96+ vortec distributer. The vortec igntion system is actually very good, and works much better than the earlier CC-HEI ones. Its also possible to use a standard non electronic throttle with a DIS setup if you use the right year PCM, or make changes to the calibration in the PCM. I dont know if HP tuners will support it. Its important as it will impact which intakes and TBs you can use with your setup.

Im working on getting some DIY support for the '411 based systems, but it takes a lot of time to get it all together.

 

Man, no offense, but I have done my research for 3 1/2 years now on third gens and have followed Stephens posts to a T. I don't need the whole "omg you need blah blah blah to make it work." I know what will make it work, and this is exactly why I didn't want to post my ideas. I like criticism, as you build your ideas and perfect edges based on it. But not this type. :\

Dropping a big block in will be cake considering the mounts are the friggen same. Procomp cheap *** aluminum heads that flow 350+ CFM and a nice cam with 11:0 compression. Thanks.

Anything over 250+ RWHP depending on weight of the car is too much for the street IMO, anything else is just bragging.

I already have a Heads/Intake 99 Z28.

Building a 383 or 400 is taking a step backwards for me. I wouldn't be able to retain any reliability or streetability at my 700 RWHP goal. A big block with fuel injection would do this without breaking a sweat.

The car already has subframe connectors, will be getting an 8.8 with a Stage 3 T56.


I have done my complete research on what is needed to run a big block in a third gen, and the EFI part will be cake. And unfortunately buying those kits is a waste of money.

My basic setup:
Manifold for Injector Setup: $450
Wiring Harness + PCM from an LSX/LQX: $300
Fake Dizzy: $400
24x Cam sync gear: $30
~60 pound injectors: $250
90MM LS1 TB: $300
Cam Sync Sensor: $90
Coils: $100
Timing cover: $100
-----------------------
$2000, all prices are over-estimated(Especially if I can get used) and I get a lot more than what those kits provide.

Headers will just be the hooker swaps since this is not a tall-block build.

If you like, I can walk out and take a picture of my core. It's a 90 RS that does not have an engine, a transmission, or a rear end. (Anymore.)

Back to vetteoz: Now, it comes down to what type of seal would I have to run.

The only thing that i can see holding me back, is that if I have to still use a 2-piece RMS when using a newer oil pan and cover with an older block, is will the timing cover seal?

The whole problem I hear is that the gaskets/shapes are correlated. If this is not true, then I don't see why using 2 piece RMS with a newer pan and timing cover would not work.

 

You know, if you had simply posted what you where trying to achieve in the first place, you can avoid a lot of hassle. People cant read your mind over the internet. Nobody knows that you already have this, that, and the other for your car, and are not interested in hearing any other options, or criticisms. We have no way of knowing, and its hard to assume just based on one or two sentences what somebody knows, or doesnt know. Hence, people assume nothing and start from the bottom, and work their way up. Sorry if that offends your intelect. I dont mean to seem like Im talking down to you, but its hard when you have to drag everything out of a poster and then get railed on for doing so.

 

Keep in mind that you will also need tuning software as well. I would not count on the PCM working right away. These PCMs are still partially speed density based, and absolutely demand tuning to make them work properly. There are a lot of inputs that the PCM will expect to see, but you may or may not have wired up, such as the trans range switch, or gear selector and clutch switch. My setup would not run intially as the PCM thought that the car was always in neutral (manual trans). You will also likely get CKP sensor relearn errors as the PCM has fairly stringent requrements for the timing signal from the CKP sensor. Also, dont forget about a new pump, and the necessary fittings, regulator, etc. since the stock RS pump only puts out 12 PSI. Additionally, the wire harness will need to be spliced into the existing one, and many of the pigtails and such will not be quite the right length for a third gen as its from a different car, so it may require some massaging. Wiring diagrams will be a godsend when your doing this.

As for the estimate, Id tack on another grand or so for all the extras.

But... Im sure you already know all of this.

 

Actually, it is worth it as the wire harness is designed with everything you need to make it happen. Just seperate out the body harness, splice it into the new one, and plug it all in.

As for the firing order differences you mentioned, these should be changed in teh calibration as it will effect which cylinder the PCM thinks is next in teh firing order. At the wire harness, the PCM doesnt actually differentiate which cylinder is next in the firing order. Instead, it simply activates the injector drivers in order from 0 to 7, and the way in which theyre wired determines which way they are fired. The firing order comes in when the PCM goes to determine when the engine is coming around to the #1/#6 pistons to establish the sync with the cam and crank sensors. Its a good idea to update the firing order tables in the calibration to match the engine in use. I would imagine that most tuning packages have these defined, but Ive never used any of them as I use tunerpro instead.

Theres also things like the anti-theft feature. The PCM will expect to see a signal from the BCM that its OK to start if the car was originally equipped with that feature. Most have a way to disable it so the PCM wont disable fuel delivery.

While this isnt "cake", its not extremely hard, either. But it can be if your not careful. The PCMs are quite complicated, and they can make your life difficult if your not familiar with them, and how they function. This isnt on the main topic of your thread, but its worth keeping in mind so you dont get an engine that just cranks when you turn the key.

 

I must be a real sucker for abuse, but I asume that your using the later style timing chain cover? GM redid the sealing on those, so you need to be careful when retrofitting one.

For example, the SBC one requires a different gasket face as it uses a built in silicone gasket. These leak like hell when you use them on a gen I small block as you have to RTV the hell out of it, and the cheesy plastic squirms around when it warms/cools, and breaks up all the RTV, causing the engine to puke oil all over the place. I dont know if the same issue applies to a big block. If it does, thats enough right there to wait until the right cover becomes available thru the aftermarket.

How about this: why dont you simply just get one from a yard off of a late model BBC truck, and compare it to an older style timing chain cover for a BBC? That will cost, what, maybe 50 dollars or so? To me that makes way more sense than trying to convert the RMS sight unseen.

Edit: heres a pic of what they look like: http://www.summitracing.com/parts/NA...0954/?rtype=10. It does look like you might run into some issues with it as the bolt pattern appears to be different from an older big block.

Edit: heres some more info, all using google. http://speedtalk.com/forum/viewtopic.php?f=1&t=20110 That kind of thing can save you a lot of time. Much better than doing a conversion on a block and finding out in the end that you cant do what you want to to start with, but thats sort of irrelevant as the initial proposition was impossible. Dont put the cart before the horse.

 

I was thinking the opposite.
Will a MARK IV pan seal to the later timing cover?

You are stuck with at least the rear section of a MARK IV pan on a 2 pce block because as I show above with the SBC
example , the seal arrangement is different

 

It looks like GM also changed the bolt and sealing style as well. That should also be taken into consideration. I think they did what they did with the later SBC one and just ommited bolts, so it should still bolt up to the block. Cant say how it will seal, but if its like the SBC, it might be worth it to hold off until the aftermarket comes out with something.

 

Dimented: If I could find a mark V or VI in my area, I would grab it and this post would not be necessary. The Ram Jet 502 that EFI Connections already built if I am not mistaken did what I have described doing, which is where I got the idea from.

Remember, this all works on a Mark V, VI block. Period. It's been proven. And the Mark VII is literally an LSX BBC as well. What I am trying to do is do it with an older block. Dimented, you seriously need to get off your high horse, ok? The LS converted to a BB has been done, if you don't beleive me. Google it. Like you suggest. It's already been ****ing linked to in this thread though which is the sad part.

Of course the bolt pattern is different. But guess what einstein? On the later blocks you can use an older blocks timing cover to drill the holes in a newer block to run the older timing cover. This should easily be done on the older block, but guess what. The original 6 bolt holes if I am not mistaken are ALREADY the same.

GOD. And the last link you posted, I have ALREADY COVERED. I have been saying this whole time, there is an issue with the timing cover and the 1 piece/2piece designs when trying to retrofit newer onto older. DEAR LORD. Thats what this WHOLE DISCUSSION is about, because if there WAS A WAY to convert an older block to a 1 piece RMS, then this problem DOESN'T EXIST.
Don't you feel intelligent now?
Internet warriors, trying to one-up everyone, one post at a time.

How about this? (LOL) Stay the **** out of my thread.

 

vetteoz: I very much thank you for the intelligent back and forth I have had with you so far. From what I have read, the newer timing cover does not work with the older pan because of seal placement. I

have not been able to test this, I finish paying off my 99 Z28 in February and then I can start sinking a lot of money into this car. but I been planning the build whole time I have been paying that car off.

The only thing I can think of is welding the front half of the newer pan to the back half of a newer pan.

Some theory.. Now... the big question is what seal oil pan seal would you use? I know of the multi-piece design for the Mark IV's, however I do not see one for the newer blocks. If there is one for the newer blocks, then I could see using the rear 2 piece rear main seal and oil pan gasket. Then up front using the 1 piece gasket for the rest of the oil pan.

The only problem is.. they don't make the multi-piece gasket as I stated. Would it be possible to make your own by cutting the newer one?

 

Insulting everyone that comes by to help or discuss. Classy. I assume at the ripe old age of 22 you have many builds under your belt. I KNOW that the bottom seal is different. I know the existing bolts still line up. YOU mentioned that, and its obvious by visual inspection. BUT, have you also looked at the sealing that they use? GM changed the sealing design on teh covers (NOT the goddamn oil pan, but the seal on the block surface) on the later gen engines. Im curious if its like the SBC where it cant really be used. Yes, on those the bolts line up, but the gasket surface is different, and doesnt seal worth a damn.

I dont know if this is an issue for the big blocks, it does not sound like you actually have a cover yet. If you do, then simply mention that the sealing will not be an issue rather than insult everyone that doesnt rub your ego the right way. Im thinking of putting together another truck at some point, and I may use a BBC, so Im curious myself, thats why I asked, if you want to know. Both you and the poster in that other thread did not mention that they actually checked the newer style cover.

So I will re-iterate this again so it gets thru your ego filter. IT LOOKS LIKE THE SEALING TO THE BLOCK MAY BE AN ISSUE ALSO. IS IT?

Edit: have you bothered to ask EFI connection if they where working on making stuff for the older blocks? If there is enough of a demand, they and TPiS may put out a cover to adapt the newer EFI to older blocks. Your not the most friendly person in teh world, but sometimes if people band together and voice interest in an application, the aftermarkets will resond with new parts to fit the demand. Maight be easier waiting rather than trying to bastardize something to make it work.

 

You know he's a mod right?

I mean whether you're right or not it wont do you any good to bite the hand that feeds. If it were me in his shoes you'd probably have mysteriously vanished by now :[

 

Bite the hand that feeds? Hes lucky I didn't report him to real TGO mods for coming into my thread with his first post. I'm sick of regular people like that, and MOD's damn well better not be that way for sites dedicated to cars that we have a passion to do things with. It's like that dumb TPI post in the LSX section.

"Why does it have to be a big block? Excess baggage.. cost.."

I didn't post asking what type of block to use. I did not post how to make a BBC work in a third gen.

This was assumed that I was a stupid kid who did not know what he was doing. And I called him on it. I did not feel the need to discuss my project with him at that point on an intelligent level.

Does anyone notice there are 3 other posters in this thread that did not need ANY information other than what I gave them?

One of them I have had the best conversation with.


Dimented. Your concern is the sealing of the timing cover mating to the block and not the oil pan. I agree, there could be a problem.

What makes me think will not be problem is already mentioned, the plastic timing cover. (Am I allowed to link to LS1 tech? If not just remove it.)
http://www.ls1tech.com/forums/conver...e-e38-ecm.html

This is the post by the EFI Connections person who did the conversion. He welded the two metal timing covers together to create what the plastic one is. This should fix the flex caused by the cooling down and heating up that would stress and break the RTV seal on the bottom where it will be most needed.

Now.

S10Wildside (OP in other thread) goes on to say

Which is where my concern is coming for in regards to the oil pan gasket.

Again I will ask, as this can really be directed to SBC or BBC or people who just like to do things on their own.

This would be used with the Franken-pan.

And one more thing Dimented. Why let someone else do it? I don't understand. I don't like to let other people change my own oil, let alone asking someone to come up with an idea to fix my problem that could take forever and will more than likely be the same idea.

Hey I could even market it. Haha.

I do beleive people can band together. Which is why I posted this on this forum. Remember, all aftermarket companies.. their people.. are us.

Remember that.

I see your interested in doing this. If you like, I can give you part numbers and details on what you need for the Mark V/VI blocks.

 

The problem with that is that nobody knows what you know, or what your trying to do. Converting an early BBC to a one piece seal on the face of it seems absurd due to the differences between the two RMS systems. Stating right away that your asking this because you want to convert an early BBC to a later cover so you can use SFI would immediatly clear things up, and prevent posts like the ones you got as people would have a much clearer picture of what your trying to achieve. Unless you deliberately like to argue with people over the internet, keep this in mind and youll get much better and more positive feedback.



Because they have access to a full machine shop, and are equipped to do things like this. I was originally going to make my own timing chain cover for my retro-roller SFI conversion by welding a boss onto a metal one that I had. I have access to a basic machine shop, and I probably could have done it without too much issue. But, it didnt seem to make sense as there was already one available that was CNC'd to dimensions more precise than what I could achieve with a steel cover.

I guess it all comes down to what you want to to, and how much your time is worth to you. Personally, if I were in this situation and had a blank slate to start with, Id probably just pay the extra money for a later model BBC core, and work with that instead to sidestep the issues with the oil pan seal. Your going to need to strip the engine down, and clean up the block and do the necessary maching, and upgrade the rotating assembly either way, so its just a little more water under the bridge at that point.