84 block vs 87 block

[kraus]

I recently had another rod failure in my fresh motor.Machine shop had done it twice for same problem. Said it has weak rods, so they think i should put rods in it.I don't want to take it back to them even tho they will cover all maching,and parts.Except i will have to pay to put rods in it.So my freind Walt Judy found a 84 gn motor locally rebuilt not assembled yet.( built by someone he knows)It has a set of 30 over wiesco pistons,stock rods and a stock crank.Question i have is what is the difference from 87 to 84 block, know no oil return in 84 block but what else is different?Or am i better off letting them go thru mine again,and pray it don't fail again.Both times i have had less then 1000 miles on it before failure.

 

[charlief1]

block has a more open lifter valley and some say it's weeker but no proof tho this. Hw did the rod fail?

 

[A2000RICH]

block has a more open lifter valley and some say it's weeker but no proof tho this. Hw did the rod fail?

GM Built the 109 block for the specific purpose of strengthening it for the intercooled turbo motor application-----would not have made much sense if they went to the extra cost and trouble and didn't acomplish at least some improvement............RC

 

[A2000RICH]

I recently had another rod failure in my fresh motor.Machine shop had done it twice for same problem. Said it has weak rods, so they think i should put rods in it.I don't want to take it back to them even tho they will cover all maching,and parts.Except i will have to pay to put rods in it.So my freind Walt Judy found a 84 gn motor locally rebuilt not assembled yet.( built by someone he knows)It has a set of 30 over wiesco pistons,stock rods and a stock crank.Question i have is what is the difference from 87 to 84 block, know no oil return in 84 block but what else is different?Or am i better off letting them go thru mine again,and pray it don't fail again.Both times i have had less then 1000 miles on it before failure.

in my opinion you are not using good judgement if you pay the same shop to rebuild your engine because they claim the rods were "weak" -----what kind of an excuse is that?????-------what was it about the rods that supposedly made them weak-----

 

[kraus]

both times it failed they covered it i didn't pay a dime.They are saying the rods are stretching....

 

[Jerryl]

Here is an old link to answer one question.

http://www.turbobuick.com/forums/ge...53511-14-bolt-hot-air-block-will-hold-up.html

 

[A2000RICH]

both times it failed they covered it i didn't pay a dime.They are saying the rods are stretching....

really sounds like they are doing something wrong

 

[novaderrik]

rods don't "stretch".
find a new builder.

 

[WIKEDV6]

Here is an old link to answer one question.

http://www.turbobuick.com/forums/ge...53511-14-bolt-hot-air-block-will-hold-up.html

I am in the process of removing a 109 block with two steel caps and stock crank to install an 85 block with two steel caps and a steel crank. Obviously someone had enough confidence in an 85 block to spend the money and install a steel crank. I haven't seen one break yet. I have seen a 109 block split right in the middle of the valley but they were trying to get that block into the 8's in 2004. I will trust an 84-85 block deep into the 10's until someone shows me otherwise. I have seen 4.1 blocks go 132mph and the valley looks as same as 84-85 block. I guess you can break anything if you detonate the crap out of it. If the machine work and the assembly are done right it will hold up assuming that you don’t detonate.

Did you loose a rod, you may have detonated that cylinder and therefore the rod got out of round. They just don’t stretch. Check your tune and that particular injector of the cylinder you spun the bearing.


HTH
Prasad

 

[paintitblack]

I have seen a 109 block split right in the middle of the valley but they were trying to get that block into the 8's in 2004.

Was that at Norwalk? I remember seeing a guy do that, and it was about that time. It was wild, and it was split pretty wide from what i remember. Definitly not repairable, but would make one hell of a conversation piece.


On the blocks the 84 and very early 85's had 14 bolt oil pans vs. your 20 bolt. Most 85's were a 20 bolt pan. There was no turbo oil drain boss in the casting and no coolant drain plugs. The castings in the lifter valley are different and i do believe the 109's are a little stronger. IMO i think the oiling is better with the earlier blocks because of the more openings in the valley (more oil dropping on the cam lobes). And i also think the deck height is taller on the earlier blocks too. I believe that in 86 on the 109 they shortend the deck height so they could use composite gaskets replacing the steel shim head gaskets for the hot air. Someone correct me if i'm wrong on this or has anything else to add.


I wouldn't be afraid to put some serious power on it, it should hold up just fine.


If i were u i would have another shop check the parts. 2 rod failures in that short of time isnt good and i would imagine that there is some serious damage to the crank by now. Take it to someone who is very familiar with buicks, or even olds or pontiacs (they all kind of carry tight tolerances). Brian.

 

[kraus]

talked to them today expressed my concern on ROD STRETCH theory.Also expressed the fact to failures in row haven't even turned boost up or armed the alky yet.Boost is at 10 and i got rod bearing failure ,so engine continues to talk and tells me left rods tolerence loose hoping to absorb some of abuse.Right there i said i just want what is fair and will take motor else where.So i have motor out ,called some other connections to pontac,olds builder.He said swing over with short block and we'll see what happened so monday i am taking it there and were going to take it apart and see....

 

[84BuickGNYorkPA]

Good luck with your motor, what part of the world are you located? Maybe someone on here can steer you in the right direction...

Chuck

 

[turbo6mike]

painitblack I was that guy at norwalk last year.One of the center cap broke and everything came down with the crank.

 

[WIKEDV6]

Was that at Norwalk? I remember seeing a guy do that, and it was about that time. It was wild, and it was split pretty wide from what i remember. Definitly not repairable, but would make one hell of a conversation piece.


On the blocks the 84 and very early 85's had 14 bolt oil pans vs. your 20 bolt. Most 85's were a 20 bolt pan. There was no turbo oil drain boss in the casting and no coolant drain plugs. The castings in the lifter valley are different and i do believe the 109's are a little stronger. IMO i think the oiling is better with the earlier blocks because of the more openings in the valley (more oil dropping on the cam lobes). And i also think the deck height is taller on the earlier blocks too. I believe that in 86 on the 109 they shortend the deck height so they could use composite gaskets replacing the steel shim head gaskets for the hot air. Someone correct me if i'm wrong on this or has anything else to add.


I wouldn't be afraid to put some serious power on it, it should hold up just fine.


If i were u i would have another shop check the parts. 2 rod failures in that short of time isnt good and i would imagine that there is some serious damage to the crank by now. Take it to someone who is very familiar with buicks, or even olds or pontiacs (they all kind of carry tight tolerances). Brian.

The 109 block that I was referring to was split right through the middle of the valley. The motor was build by Pete Barton at ANS Performance in Melrose Park, IL. It had a good crank, I think BMS, good rods, solid lifters, good pistons and I don't recall if it had two steel caps or 4 but the block split right in the middle all the way across front to back.
The 109 is a superior block, however the 84-85 blocks will live in most of the cars that run 10.50 or slower.

One more thing, if you are using the 84/85 block you need head bolts that are specific to 84/85 blocks. You can use the head bolts or studs that are made for Buick Stage I block made by ARP. The 84/85 blocks have the head bolt thread come all the way to the top of the deck where the 86/87 blocks have the thread recessed about a 1/4" or so below the deck. So if you use the 86/87 head bolts in an 84/85 block you may crack the deck of the block or damage the threads in the block. Also the head will not torque down the way it should.

HTH
Prasad

 

[kraus]

Iam in north fond du lac WISCONSIN.

 

[getchasum]

continues to talk and tells me left rods tolerence loose hoping to absorb some of abuse.

There's your answer....... poor machining and most likely poor oil pressure.

 

[kraus]

well i pulled it apart myself found one center main cap broken,cylinder four rod bearing spun around on top of each other.I am thinking rod spun and block oil passage off causing cap to break?

 

[TURBOELKY]

well i pulled it apart myself found one center main cap broken,cylinder four rod bearing spun around on top of each other.I am thinking rod spun and block oil passage off causing cap to break?

this is where the guys will swear by billet caps. But it is obvious you have other issues, causing a cap to break
rods to bend, bearings to spin!!! did the cam go flat too? geeze. find a new machinist!! asap.


oh yeah, can we get some pics!

 

[kraus]

this is where the guys will swear by billet caps. But it is obvious you have other issues, causing a cap to break
rods to bend, bearings to spin!!! did the cam go flat too? geeze. find a new machinist!! asap.


oh yeah, can we get some pics!

I don't have bent rod i don't think,roller cam hope not flat,ya i got issues that is for sure.Pics i will try and post as soon as i get back out in garage tommorrow..

 

[charlief1]

OWITCH!!! I feel your pain dude.