Boring bar options for 3.0 litre mercs

**LOSTINJ** · 12-02-2015, 06:55 PM

been looking into purchasing a professional boring bar and stand in order to machine my own blocks since my STR Shaun Torrente engines failed with under 5 min run time .

Looking @ Kwikway model FN with the 054 stand , anybody used this set up on 3.0 litre Merc ? I see an issue with the 054 plate as it will interfere with the exhaust chest .

**baja200merk** · 12-03-2015, 10:13 AM

YOu use parallels (spacers) to move the block down so the chest clears the table.

**ChrisCarsonMarine** · 12-03-2015, 12:54 PM

I'm pretty sure unless you build a lot of motors you will be better off sending your blocks to a good shop to get them bored.I have several bars,including an FN,and although i have the kwik-way table I don't use it...I built a custom table that the block bolts under using the head bolts,so the block is 1. not distorted by the clamping force on the deck ends and the main ways...and
2.the deck and cylinders are stressed the same as if the head was torqued in place...resulting in straight bores when the engine is back together,similar to using a torque plate in the automotive world.On performance motors we bore with the crankcase front torqued in place too...stressing the bottom of the bores as well.
The parallels/main way method of clamping was really a universal system for cast iron automotive blocks...works but is a PIA to keep a good paralell cut and bends the block under clamping pressure.
If you insist on getting your own machine I would suggest on of my favorites,the Van Norman 777-S...Way less money,easier to use,harder to break,less expensive tooling...I use mine almost every day.Also,you can have an adapter plate made to bolt to the block that the bar mounts on...presto,no need for a table at all,lift the 185 pound bar onto the block with a cherry-picker and have at it...
Remember to champher the ports and hone to finish size before a hot soapy water wash (several times)...then oil the cylinders before they rust ,good luck,Chris

**baja200merk** · 12-03-2015, 01:37 PM

I use a 777s with a torque plate I made which has counter sink bolts and tha bar sits on it.

watch this video at the 25sec mark they show cyl distortion on a steel cummins block. Imagine how much an aluminum block distorts

http://youtu.be/Cx_DCUht-Xg

**LOSTINJ** · 12-03-2015, 07:54 PM

Thanks Chris and Baja?
First off I decided to go ahead and build my own powerheads after a great deal of money spent with STR Shaun Torrente 3.2 Litre EFI strokers that were ported incorrectly ( no chamfering) and debris left in block scored new bores .

Chris I spoke to you after this happened and have purchased reeds from you for other boats I have , great reeds ! Here is my logic , got a quote for 4000.00 each power so the 3000 K I spent Kwikway fn with stand and special blind hole cutter is cheap . By the way even though I have never bored a block I have shop of my own and kind of said why not . Fortunately for me a close friend has well known machine shop and was top fuel crew chief @ one time so I'm in good hands !

Merk ,
Great thread for block distortion and I have been concerned as well so the block will somehow be bolted to thick plate with counter sunk holes . My friend who owns a machine shop will only bore blocks certain times of year as contraction-expansion from different seasons . Buying a honing bar next !

**flabum1017** · 12-04-2015, 02:40 AM

Thing about machinists..... no matter who you use, the guy who puts the engine together is really responsible for cleanliness and making sure everything is good (such as chamfers (sic) ). I can't tell you how many hours I spent massaging blocks to live after getting them back from reputable machine shops. It really is not the fault of the machine shop (and many have disclaimers) if the work is not checked before assembly. A lot of machine shops I have used will tell me to do the cleaning and checking and it is basically my responsibility to be sure it is right before I assemble it. Every engine I put together, even if the machine shop sends me all the parts, is triple checked upon assembly. Most of the time the machine shop does a good job, but it only takes one screw up to kill a lot of peoples' reputations (and I have caught a lot of screw ups). It's better to be thorough than to trust someone that everyone swears by. As far as getting it right, torque plates are the way to go and to go extreme is to use ovens to heat things up to temp for final measurements. But even that is not full-proof because bolting on a cylinder head is not the same. Nothing is an exact science, that is what gaskets are for.... to allow for discrepancies. (and sealing).

**LOSTINJ** · 12-04-2015, 05:57 AM

does anyone manufacture a torque plate for 3.0 litre merc or do I have to mill my own ? If I have to make my own I may start with a stock head and machine it

**rock** · 12-04-2015, 08:33 AM

I use an FN with a torgue plate. I have also made caps to attach the block to the lifting bar. Once block is situated I have 1 1/4 threaded rods that fix block to bottom of table.I have removed the float clamp assembly and the pneumatic centering system. Without those changes it was iffy at best but since then it has been spot on. Lots of ways to skin a cat.

Rock

**baja200merk** · 12-04-2015, 09:06 AM

I recently came accross a 2.5 block a buddy had bored by a reputable shop. Mercury dealer, racer and machineist for 30 years. They bored all 6 holes .040 over and they did not clearance the aluminum below the sleeve. I told him the aluminum is gonna grab the piston and scuff it. first pass wide open guess what happened

boom.

I always make sure there is plenty of clearance. Sometimes the aluminum under the sleeve is not bored exactly strait with the sleeve so you can have .020 clearance on one side and .000 on the other side. I made a cutter to clearance the bottom I've never had a problem with .040 over.

**cali kid** · 12-04-2015, 10:08 AM

Originally Posted by LOSTINJ

does anyone manufacture a torque plate for 3.0 litre merc or do I have to mill my own ? If I have to make my own I may start with a stock head and machine it

Torque plate kinda a waste of time, since 3 liter merc is open deck. Bolts are nowhere near the bores. No offence, but overkill on this motor.

**Lil' Blue Rude** · 12-04-2015, 12:36 PM

Does anyone have any pictures of their boring bar setup they'd mind posting? Thanks.

**ChrisCarsonMarine** · 12-04-2015, 01:21 PM

Originally Posted by cali kid

Torque plate kinda a waste of time, since 3 liter merc is open deck. Bolts are nowhere near the bores. No offence, but overkill on this motor.

Well,put your block in the clamp table,lightly clamped with parallels on the ends. Install a dial indicator on the table reading the height of the center cylinder top and zero it,and while you're at it measure the center cylinder for roundness 1/2 inch from the top,make notes.Now tighten the clamp enough that you don't worry a lot anything moving...like you would to bore...and see if the dial dosent read + .010~.012.Check that cylinder for roundness,I think you'll agree bolting to the table with the head bolts will result in much better job.
This is just my observation,and I'm sure with saddles on the mains and more parallels or a system like Rocks good results can be attained,but the table as sold and used as the instructions explain is not capable of producing acceptable results on outboard (or any high performance blocks)in my opinion.
Is the tourque plate critical?,probably not...is the factory clamp method good?,not for me,so I solved the problem by mounting the block and bar on opposing sides of a Blanchard ground turret table that mounts all the modern blocks by the head bolts,they come out very straight,

**cali kid** · 12-04-2015, 01:29 PM

Originally Posted by Chris Carson's Marine

Well,put your block in the clamp table,lightly clamped with parallels on the ends. Install a dial indicator on the table reading the height of the center cylinder top and zero it,and while you're at it measure the center cylinder for roundness 1/2 inch from the top,make notes.Now tighten the clamp enough that you don't worry a lot anything moving...like you would to bore...and see if the dial dosent read + .010~.012.Check that cylinder for roundness,I think you'll agree bolting to the table with the head bolts will result in much better job.
This is just my observation,and I'm sure with saddles on the mains and more parallels or a system like Rocks good results can be attained,but the table as sold and used as the instructions explain is not capable of producing acceptable results on outboard (or any high performance blocks)in my opinion.
Is the tourque plate critical?,probably not...is the factory clamp method good?,not for me,so I solved the problem by mounting the block and bar on opposing sides of a Blanchard ground turret table that mounts all the modern blocks by the head bolts,they come out very straight,

I wish you were nearby. You would certainly have my business.

**Chaz** · 12-04-2015, 04:38 PM

Originally Posted by baja200merk

I recently came accross a 2.5 block a buddy had bored by a reputable shop. Mercury dealer, racer and machineist for 30 years. They bored all 6 holes .040 over and they did not clearance the aluminum below the sleeve. I told him the aluminum is gonna grab the piston and scuff it. first pass wide open guess what happened

boom.

I always make sure there is plenty of clearance. Sometimes the aluminum under the sleeve is not bored exactly strait with the sleeve so you can have .020 clearance on one side and .000 on the other side. I made a cutter to clearance the bottom I've never had a problem with .040 over.

Out of sight , out of mind ...

The 3.2 stuff brings the skirt way out of the bore at BDC . But that is nothing like doin a .229 over to have ya campin out at the green wheel ...

**53w** · 12-04-2015, 11:38 PM

I used to get my racing blocks done by Ruck, I wanted to do my own work and asked him to teach me. I told him I was going to order a boring head and wanted to know the basics.
He said if I buy a head he never will show me, you must build your own head to get a good one. Anything you buy will have issues. He showed me his own custom made boring heads. I went and built one and he did show me what was all need to get straight and round, dress bit to cut correctly. That was just on small inline twins.

His v6 stuff was all custom made fixtures and boring heads also. They located bores perfectly off of crank centerline.

There is a lot more to it then just ordering a boring head out of magazine and expect to get a good out come. But if you really want to do it, it can be done, but you will have to build the tooling to do right.