PontiacBonnevilleClub.com

Hey guys, new here and figured this would be an appropriate place to start posting and asking alot of questions.
I currently have an L67 from a 1998 Bonneville with 240,000km and blown head gasket. I've never heard it run, but I plan to rebuild, hone and add some performance while I'm in there. What I am aiming for is a fast, reliable vehicle. Which brings us to my first question, how fast is un-reliable? I am hoping to make around 300whp.

I've done a lot of reading already, and with that figure in mind, I'd would need:
-S1X package(heard nothing but good things)
-larger injectors
-fuel pump wiring kit(larger fuel pump?)
-header of some sort, does anyone know if the ZZP SS headers fit the bonneville?
-N* throttle body
-3.4? MPS pulley
-and all the bearings, gaskets...
Does anyone see anything that I am missing? or should be doing differently?

I'll will be deleting the A/C, is a delelte pulley really necessary? do they not make a belt that just goes straight to the alt? Or is the motor mount in the way?
EGR and charcol canister will be deleted, unless these affect the engine negatively.

So far, I've only managed to pull the engine, subframe, fuel pump/sender and the wiring harness.
Here are some pictures from a few days ago:



The wiring harness, which reminds me, if you couldnt tell we're scrapping the car and the engine is going into:

And the builder:

After we pulled out the engine, Eric pull out the tequilla... lets just say its a good thing the car wasnt moving

First of all, I strongly suspect you DON'T have a blown head gasket. That's extremely rare to the point of being nearly unheard of except in cases of severe abuse. Most likely, the lower intake manifold gaskets have failed:

www.dex-cool.net

This may make you re-think some of your plans for the motor, as the coolant rusts the crank and bearings VERY quickly if the oil wasn't drained immediately after the failure.

Thanks willwren, the 'head gasket' is what stopped the previous owner from driving it this spring. He verywell could be wrong as he didnt have any documentation to back it up. Regardless the engine is going to be dissassembled and inspected as I go along, and hopefully find what really failed.

With what you are planning it should be reliable.
Take lots of pics and post them here.
We can help guide you with some advice as you go.

Always good to celebrate daily victories with a squeeze of lemon, some salt and a shot of liquid.

Highly doubt it's a head gasket but a possibility I suppose. It could even be a holed piston....that's more common. I'm sure you'll tear it down to find the root cause.
Honing cylinders with a tight tolerance engine such as this is not recommended. Just send the short block out for a proper $1,000. freshening. That way you know it's good for adding another 100 hp and be reliable.

I agree, have the block, crank and heads checked and freshed, and maybe go with a .020 set of pistons and a bore. If you're planning on some good HP, studding the heads is not a bad idea.

Thanks for the info. I planned on sending the bare block out to be magnaflux, hot tanked, new freeze plugs and cam bearing. In terms of honing, I didnt think any material is removed. Even if I replace the rings would honing still not be recommended? The head would also be sent out to be checked, lapped and new valve seals pressed in. What would they check for the crank?
ARP stud are already in the list of parts, as is ARP rod bolts and main studs.

I will be taking a lot of pictures through out the process and will be looking forward to everyones input. Progress is a little slow as I am working on prepping and cleaning the subframe and its components right now.

As long as you don't have more than 75,000 miles on the block it should be fine to lightly hone and replace the rings with plain cast units. If you want to go with the longer lasting Cr-Mo rings then you should get a re bore.

Are you planning on balancing and blue printing the engine?

I apologize in advanced if I might asking some silly questions, but this being my first rebuild, I just want to make sure I get it right. Thanks for the responses so far.
Now that I look at it, the rob bolts dont seem to be TTY. Therefore replacing them doesnt seem necessary right? With that in mind, if I only hone the cylinders and replace the rings and bearings, balancing seems redundant to me... correct me if I am wrong.
The engine has about 150,000 miles on it, so I can see at least honing being required. But if everyone tends to bore these vs honing, then I'll bore .020 and get some forged pistons.
I have the full GM service manuals, and was planning to follow their specs. I wouldnt really know where is to start with blueprinting otherwise.

For the slight extra cost balancing the rotating assembly adds, it's totally worth it. Your engine will be as smooth as glass.

Will watch closely. I plan to transplant an L67 into my 94 L27 car. I want to performance enhance my whp to near your mark. The chat here is already way over my head.

Good Luck

Do a compression test before you disassemble. That will tell you if you even need to worry about the cylinders/pistons/rings.

Stripped the entire block and went rather flawlessly except for the crank removal. We'll get to that later, heres the cause of failure for the engine, starts with the coolant passage looking a little clogged:

and then a chipped piston, we figure from running to hot and lack of a coolant flush:



The bore to the chipped piston is actually fine, which makes me wonder what happened to the shard(s)?

The next bore, I forget which, had a score mark just barely felt by my nail:


I think a bore will be necessary, I'll have the shop determine this.
heres the second worst bore which doesnt have me worried as it just seems like wear and cannot be felt at all:

Walls are pretty clean other than the one score mark.

Bearings to the chipped piston, all rod bearings are the same as this:


I'll be replacing these.
I havent inspected both sides of every bearing yet, but no bearings appear to have spun, unless one did a perfect 180 or 360...

Main journal #4:

This can be felt and I figure it was from removing the main caps from hammering down on the counter balances. I was being pretty diligent and careful, but i guess not enough. If I do this again, I'd get the tool to remove the caps as the alternative process is cumbersome and destructive.
Does this make the crank toast? I cant imagine it would.
The worst rod journal, which isnt felt by the nail. all the others look perfect:

I dont have the picture of the main bearings but those will be here soon. Same wear as the rod bearings.
Its too bad the machine shop is closed today, because I'd really like to have it off to them to work on and figure out if I need larger pistons or not... I think I am just going to go .020 to get my order in.

That's a main journal that's got that small mark? It can probably be machined down, and you'll have to run oversize (IIRC) bearings. Depends how deep it is, though.

Oops, your right, its a main journal. Correction made.

I kind of had that idea of machine it down and then getting a bearing sized. Just need to do some research now on that procedure.

Judging by the pics, 0.010 oversized pistons would be all the bigger you need if you want it bored. Even 0.005 would clean that up, but I don't know if they are available in 0.005 over? They could probably just hone and use stock size too, but if your gonna buy new pistons you might as well go one size over (just my opinion), you could use new stock size too. As for the crank, that could probably be polished and use stock size bearings. But if you want it cut, then one size under will be fine as the damage is pretty minimal. None of your bearings spun. If one did, it would be very evident. It would be badley scored and the alignment tabs on the bearing halves would be sheered off.

Technically speaking, if you want to save money, you could get by with......
A full gasket set
New bearings (all of them, crank, cam, balance shaft)
One good used piston (or new, but stock)
A new set of rings
Hone the cylinders
Polish (not resurface) the crank

From the sounds of it though, I doubt you will go that route. It sounds like you want new spec on everything. Just be prepared, I thought it was about $80 a hole to bore the cylinders? Your probably gonna be looking at a $500+ machine shop bill before it's all done and over with if you have it bored and the crank cut. Then you still have to buy all those expensive parts too.

I'm sorry, I never seem to have anything good to say. Just keep in mind that a low mileage series 3 is only like...what, $800?

Cant wait to see this all finshed up. I love those old T-type LeSabres with the cantilevered hood. This will almost be like a "Big Daddy" version of the Grand National.

...and that will be badazz!

The failure of the engine was not related at all to blocked or plugged coolant ports. Those ports (one on each side) are blind, and do not flow through. What you see is Dex sludge.

www.dex-cool.net

All Series 2 engines with DEX develop the sludge block on those blind ports. Some of us are personally experienced with chipped pistons like that. Zilla had a doozy.

As for the rotating mass, I understand that stock form will handle 400 ft lbs just fine (dare I say 500?). It's the knock of the grim reaper that causes the failures...and the knock can come from many different places, but the knock in the bottom started from the knock in the top.

Basicaly the extreme force caused by the predetonation will fatigue and break the brittle cast piston at its weakest point. The outer edges.

It doesn't surprise me that GM would cheapen out by not using true forged pistons in a supercharged engine.

In stock form with the proper octane, forged pistons aren't necessary. It took quite a bit for me to pop one. At least they had the foresight to lower the top ring a bit.