Parts advice for engine rebuild

[Mikko R]

Hi,

I had my -79 carbed turbo out for the summer couple of weeks ago.
Last summer it was suffering from low oil pressure, and burning some oil from exhaust.
I was hoping valve seals and a booster plate to oilpump would help for a while, and I could deal with the lower part of engine next winter.
Well, it appears if the engine is burning a bit of oil with low oil pressure, getting the pressure higher will not reduce the amount of blue smoke

So it appears I'm facing an engine rebuild.
Unlike most of the threads I see here, there are no goals for 1/4 mile.
A good city/highway driveability is the main focus.
First priority would be to get the car on the road again.
Second priority would be not to spend a fortune for it.
Something like a nice to have bonus would be to increase power while the engine is rebuilt.

As said, it's a 1979 carbed turbo.
For legal reasons around here, it needs to stay carbed.
During winter I ported the stock heads, and got Ferrea valves fitted to them.
I have a 86-87 GN intake manifold and turbo waiting to be modified and fitted on top of it.
Also got a project status 200-4R without a converter, which I hope to have time for during next winter.
The engine itself had 030 pistons in it already, so I suppose we're getting close to the last rebuild for it.

With that background, I was looking at some options.

SP H521NP hypereutetic pistons seem to be very affordable and available in 040 over.
Are these fine with a carbed turbo, or does it make sense to pay 300$ more for forged pistons ?
I suppose it's a safe bet to use piston rings from same manufacturer ?

On max performance buick engines book I remember reading that the stock crank would be good for mild engines. I suppose machining that one will do.

How about bearings ?
There seem to be several different materials available, with very different price levels.

Cam is then an interesting point.
It adds costs, but I read from these forums that with ported heads and an open plenum intake it might make sense to get a bigger than stock cam.
There seems to be some pretty decently priced options available.
Edelbrock 204/214 is cheap, but has higher lift than stated "safe" somewhere here
Comp 252H 206/206 would seem safe, and is only a bit more expensive.
Melling also seems to have some models, but I found quite little information about them.


Any suggestions, or pitfalls I should definately know to avoid, would be very much appreciated.

Thanks

Mikko

 

[blacknight80]

Following. How are you using a carb on a 86-87 plenum?

 

[charlief1]

To keep it carbed you need to use a 79-83 intake. The GN intake is for injection and will be to high for the hood clearance. Unless you go SFI that intake won't work so sell it. Hypers are ok if you keep boost low. The stock cam is small for better mileage so going bigger willl help power, as well as increasing boost level.

You might want to go to www.beforeblack.net and do a little reading about the system and how it works.

 

[Mikko R]

Following. How are you using a carb on a 86-87 plenum?

Hi,

I'm still wondering between 2 options.
One would be to get a blow thru suitable carb on top of it, and have the GN turbo blowing through there.
A wild idea would be to fit an intercooler with cold air coming from the scoop.

The more likely is to make a plenum larger than the doghouse on GN, and remain with the draw-throug setup.
In this case, I'm a bit worried about having a plenum full of air-fuel mixture there, so need to do some homework still

Either way, some customization of headers and downpipe are needed, but it's not like the originals fit to cobra with sidepipes anyway.

 

[Mikko R]

To keep it carbed you need to use a 79-83 intake. The GN intake is for injection and will be to high for the hood clearance. Unless you go SFI that intake won't work so sell it. Hypers are ok if you keep boost low. The stock cam is small for better mileage so going bigger willl help power, as well as increasing boost level.

You might want to go to www.beforeblack.net and do a little reading about the system and how it works.

Hi Charlie,

Thanks for the input!

The engine is not in a Regal body anymore. Hood clearance may actually be tight anyway, but the current cobra body with a bit increased scoop has pretty good room in the middle.
I planned to plug, weld and burr the injector holes from the gn manifold, to block the extra holes it has. Also the egr passage will be filled, as all that stuff is removed already.
Knock sensor I need to move to block, but is there some reasons I'm missing why it couldn't be modified for carb ?

-Mikko-

 

[blacknight80]

Hi,

I'm still wondering between 2 options.
One would be to get a blow thru suitable carb on top of it, and have the GN turbo blowing through there.
A wild idea would be to fit an intercooler with cold air coming from the scoop.

The more likely is to make a plenum larger than the doghouse on GN, and remain with the draw-throug setup.
In this case, I'm a bit worried about having a plenum full of air-fuel mixture there, so need to do some homework still

Either way, some customization of headers and downpipe are needed, but it's not like the originals fit to cobra with sidepipes anyway.

Ic I thought this was in a regal. Check out warwagon's repeat procedure thread. He has a cool blow thru carb set up and I'm sure he would give you some guidance. It's a few pages so grab a coffee and get comfortable there is lots of info.

 

[charlief1]

Hi Charlie,

Thanks for the input!

The engine is not in a Regal body anymore. Hood clearance may actually be tight anyway, but the current cobra body with a bit increased scoop has pretty good room in the middle.
I planned to plug, weld and burr the injector holes from the gn manifold, to block the extra holes it has. Also the egr passage will be filled, as all that stuff is removed already.
Knock sensor I need to move to block, but is there some reasons I'm missing why it couldn't be modified for carb ?

-Mikko-

The amount of work you're looking at is more than it's worth. Find a Weiand, KB, or something like that. Even an edlecrap with the divider removed will be easier and work well. The advantage of a NA intake is you're got a standard pattern where the carb mounts and you can just take a piece of plate, drill holes, and mount it up. There are 2 different Weiand intakes and either would be perfect, but the earlier one is an air gap style and would work better.

The knock sensor needs a hole drilled at the back of the block where the tranny mounts to the engine. There are other options now if you want to get rid of the original system and go with an updated version. Not cheap, but a hell of a lot better.

 

[Mikko R]

Thanks again for the good info!

Sorry, I forgot to mention initially, that my summer toy is not exactly a stock Regal.
It's a shortened Regal chassis, which has a steel tube frame welded on- / around it. The original chassis was again needed for legal purposes around here.
The body on it is a cobra replica body.
I actually went thru Adam's thread earlier, and indeed it is very interesting topic

I need to google a bit on the intakes. Especially if blow-thru is the way to go.
In case of draw throug, I have to make the plenum with a baseplate attaching to the intake anyway. Although even in that case I could use a carb spacer plate for the baseplate.

So these options to knock sensor would be lambda sensor based systems ?
Sorry, I haven't looked into these at all, so perhaps a stupid question. Need to google them as well.

Mikko

 

[charlief1]

J&S electronics has a couple of stand alone detonation control systems that blow the stock one away. Not cheap, but trying to use outdated stuff just isn't a smart thing to do on a turbo car. If you decide to go with blow through then find a 4 barrel intake with an open plenum, make a 3/8" thick, or thicker plate for the top, and bolt the stock turbo and plenum on. If you want to upgrade the turbo there's a link in my sig that might just give you a few ideas.

 

[Mikko R]

Hi,

I only get an error, trying to open the link in your sig Charlie.
Anyway, I remember reading a thread where you compared at least 3 different turbo housings, and made a hybrid version.
Perhaps it was this thread ?

I also got a bit confused with the cam selection.
Most of them are listed for "even fire V6" Buicks, which I figured would suit all of them, turbo or not.
But then I saw some posts here on the forums, that some cams would not fit some blocks.

Does someone know if the 79 turbo block is setting some limitations to the choise ?
I understood that valve overlap, too long duration and too high lift will easily kill low speed performance.
That combined to the lag of the 79 would not be too good outcome.

Thanks again

Mikko

 

[charlief1]

Do a search for threads I've started in the B4black section. It should bring up the turbo thread. What I did is adapt and 301 TTA compressor housing (intake side) and an 86-87 exhaust housing to the earlier carbed unit. It doubles the CFM flow. As far as a cam goes, the old 204/214 flat tappet cam is a good upgrade and has been into the 10's. Do a search on evilbay and you can find them fairly cheap.

 

[Mikko R]

Very nice adaptation you have done!

As I mentioned, I have a used 87 turbo, which needs new bearing, gasket (or whatever it is that helps for shaft play).
So with a TTA compressor that could be modified to fit the early intake and carb plenum.

If changing the intake manifold, and keeping the draw-trhoug setup. I would anyway need to fabricate a "doghouse" on top of the intake.
I suppose I could use both sides of the 87 turbo and be pretty darn careful in getting the turbo to doghouse interface to seal properly.
Somewhere I read that volume of the doghouse should be about the size of the engine to get somewhat equal mixture to all cylinders.
What I haven't been able to figure out, is if this also works with draw-through setup, when the fuel is already mixed to the air in that phase.

Probably I also need to make an adapter between the carb plenum and the compressor housing to make them fit.
The 2 bolt holes of the 87 compressor intake actually matched 2 of the holes in the 79 carb plenum, but I don't believe I'd be lucky enough for the passages to be aligned like that.

Anyway, these plans are much less urgent than the engine rebuild, so I'll have plenty of time to do research before winter

-Mikko-

 

[charlief1]

There are 2 types of oil seals in the turbos. The 86-87 use a seal that won't work on a draw through or factory HA system because of positioning of the throttle. The later design under vacuum will let oil get sucked into the air stream. Now if you're going to rebuild the stock turbo you had on the car, then use the hot side off the later one and the intake side off the original. The original can even have a larger intake inducer wheel installed, which will give you more air flow and faster boost. Just remember that with hypers you need to keep the boost low to keep from popping a piston.

As far as a "doghouse" goes, you don't want a lot of volume in the plenum below the turbo. All you need is a flat plate of aluminum bolted on the top. The area under the turbo can cause a serious back fire if a spark gets where it shouldn't be. With Adam's blow through set up it has no more than the intake for a plenum, but it is a free flowing intake. That's one of the draw backs of the original HA design. The volume is so high that you get turbo lag, and on the draw through system, it's intake is restrictive so you loose flow. The re-worked HA ones you get from champion have gutted the intake and reduced the volume which cuts the turbo lag and increases the flow into the cylinders. On the draw through intake you're got to cut the bottom open and port the crap out of it to get the flow up,

By using an open plenum NA intake with a plate on top you've got just enough volume and good flow so you can do all you need to.

 

[WarWagon]

All later Buick v6's '78 and up are even fire, low port volume heads on '78-'79 and lack of block mounted knock sensor are major difference in earlier blocks vs the later ones. Stock or modified draw through turbo systems leave a lot to be desired in power production and has it's own built in slowness perks (foot on turbo compressor outlet) not to mention it's still a hot air system albeit with fuel in mixture. Good stuff for draw through: they look cool, they are simple and relatively cheap but that is it.

 

[jiho2]

Mikko --

Just out of curiosity .... Where is "around here," where you must have a carburetor and a Regal frame, yet you are free to try wild schemes with the motor like that?

I'm in California, so my curiosity is somewhat macabre by now.

 

[charlief1]

He's in Finland so the rules are very different.

 

[jiho2]

I thought so. I've seen a little about those rules before. Very different indeed.

Those rules make ours look good.

 

[Mikko R]

Yes, "around here" is Finland in my case.
The rules are very different, and change even more when the body is changed from the car.

Adam, since all the 78- engines are even fire, I suppose the aftermarket cams sold for even fire buick will fit to the block ?
Leaving the decision of which will actually work as well. I was worried if there's some that will not even fit in.

Going blow throug with a blow through carb and the 87 intake with custom adapter has been the other option in my mind.
That would enable using the 87 turbo as well.
But what else would I actually need there ?
For low boost, is the stock fuel pump enough, or woudl I need an in-line pump to overcome the boost pressure ?
If an inline pump is needed, I assume a regulator for the fuel pressure as well.
I'm worried it might end up being pretty expensive way.

 

[Mikko R]

There are 2 types of oil seals in the turbos. The 86-87 use a seal that won't work on a draw through or factory HA system because of positioning of the throttle. The later design under vacuum will let oil get sucked into the air stream. Now if you're going to rebuild the stock turbo you had on the car, then use the hot side off the later one and the intake side off the original. The original can even have a larger intake inducer wheel installed, which will give you more air flow and faster boost. Just remember that with hypers you need to keep the boost low to keep from popping a piston.

As far as a "doghouse" goes, you don't want a lot of volume in the plenum below the turbo. All you need is a flat plate of aluminum bolted on the top. The area under the turbo can cause a serious back fire if a spark gets where it shouldn't be. With Adam's blow through set up it has no more than the intake for a plenum, but it is a free flowing intake. That's one of the draw backs of the original HA design. The volume is so high that you get turbo lag, and on the draw through system, it's intake is restrictive so you loose flow. The re-worked HA ones you get from champion have gutted the intake and reduced the volume which cuts the turbo lag and increases the flow into the cylinders. On the draw through intake you're got to cut the bottom open and port the crap out of it to get the flow up,

By using an open plenum NA intake with a plate on top you've got just enough volume and good flow so you can do all you need to.

Charlie, so the 87 turbine side could be combined with the 79 compressor side ?
From somewhere I had got the impression that they would have a different size shaft. But can't actually remember where.
This project is the first turbo, first automatic and first American car for me, so there are plenty of new things coming up frequently.

But usually takes only time and a couple of trial-error rounds, right
Below a picture of the moment, when I wasn't completely sure this project was a good idea

 

[charlief1]

All of the Buick and TTA turbo's are Garret T3 based and use the same size shaft. Using the hot side off the 86-87 turbo will give you a faster spool but you'll need to fabricate a down pipe. When you put everything together you need the seals for the earlier design so it doesn't suck oil into the intake on deceleration.