1216 Build List + Very Basic Questions

[rider384]

My bone stock 1157 motor finally bit the dust after my wastegate signal line popped off and it briefly saw 30+ pounds of boost from my twin K04 setup. Compression is currently 50-30-80-90. 

Luckily, this is an excuse to build an engine, but I have zero experience doing that. I have a workshop manual and friends who are more experienced/smarter than I am, so I'm not too worried about the actual physical assembly of the block, but more about the parts I'm going with, primarily whether or not I'm missing anything important. Bear in mind, the goal of this build is 400whp.

• Parts I have
• MTC 10:1 81mm Turbo Pistons (MTC-R1216T)
• Tool Steel Wrist Pins
• Maxpeedingrods H-Beam Rods (supposedly good for 600-800hp)
• Cometic 0.032" Copper Head Gasket C8191

Parts I am unsure about and need help with:

• Cylinder Studs: CS1127GSX - unsure of whether these will fit the Bandit 1200 block I've got, as it's listed as compatible with '86-'92 1127 blocks, but I believe the Bandit 1200 is an 1127 case, correct?
• Main Bearing Studs: MBS1100GSX - same note as above
• Head Nuts: CHN1000K or CHN10125-12, again unsure of which ones are correct. I believe it's the CHN1000K, but I just want to be sure. 

And of course the standard engine rebuild stuff such as gaskets, bearings, o-rings, etc. I'm not going to list it all, just after the big stuff.

And for my very basic questions:

• What diameter base gasket do I need? The smallest diameter available is ~85mm, I guess it's the diameter of the sleeve? What sleeve is in the 1157 Bandit motor stock? I don't have the engine apart yet to measure for myself. 
• How is compression generally lowered in the oil-cooled community? Is it by raising the head, or by raising the jugs? I've found both being presented as solutions. And, if a spacer is used, does it require 2 gaskets? 
• Cylinder Jug Boring - what specification is used as the diameter to bore to? Is it just as simple as 81mm? People talk about 2mm over, but I'm unsure if that literally translates to a bore of 81mm for the jugs or something slightly different

More questions to come I'm sure, but I'd like to start off with this as I'd like to start ordering the final parts and hit a machine shop. Any help and advice is appreciated! I've attached a picture of the bike in question just for fun.

[Kamikaze]

Turbos are beyond my knowledge im afraid....some of the lads on here will have the brains to help you

[clivegto]

You need a 2mm base spacer plate which will take the compression down to about 8:1 with your pistons or skim the tops of your pistons, this will also depend on the length of the rods you have. No base gaskets but use a suitable sealer like gaskawich on the spacer plate. Piston to cylinder wall should be about 4thou in my experience. Do a dry build and measure it yourself so you know what you have. 

Edited February 10, 2022 by clivegto

[Arttu]

I think you have to do some leg work for compression ratio and cylinder spacer questions. I mean if you want to get good results. Here's how I would tackle that:

• First you need to decide what compression ratio you want. Variables are the usual ones, how much boost, what fuel, do you have charge cooling and so on. I guess you will need something like 22-30 psi boost and proper intercooling to reach your 400hp target. On pump gasoline I would probably aim for 8.5-9:1 compression. With race gas or E85 something like 10:1 should be good.
• Piston to head clearance (squish gap) should be around 1.0-1.5mm.
• Then you need to measure and calculate the actual compression ratio with your pistons. Quite often advertised compression ratios for pistons are very inaccurate so your 10:1 pistons might be actually 9:1 or 11:1.
• Now you know how much you need to change the compression and you can check how to do that. One good option for minor adjustment is to machine piston tops if there is enough meat on them. If you machine just the dish in the middle of the top you can keep the squish band and proper combustion chamber shape. You can also adjust the squish cap within the range mentioned above. Also one option is to remove material from the head but that has relatively small effect if you don't ruin the shape completely. As last resort you can throw the squish band out of the window and increase the gap even more. But that will most likely hurt efficiency and possibly increase knock sensitivity.

[Gixer1460]

Pretty much ^^^ said above! MTC pistons have material enough for some decent dish machining - DON'T just machine the tops flat and drop them down the holes! Likewise as you've got turbo pistons - use them to adjust the CR, not spacer plates if they can be avoided! Do not lose the squish band - its worth having, if only for its anti detonation benefits. Love the claim re the Maxspeeding Rods - in what universe have they been tested to that level? Your 400hp aim is admirable, but seriously I think, maybe beyond your means / present understanding ie. like speed, HP costs money and 400hp is going to cost lots. If you can achieve the CR with head and piston work, a normal Blandit base gasket is all that is needed!

[mikeyd]

lol! ^^^^ open that wallet. All part #'s correct, use CHN1000K nuts. Heavy duty valve springs too, Titanium retainers, etc... Cylinder boring -81 mm pistons, 81mm bore. Pistons should be 20-40 thou in the hole. I set mine at 20, nitrous guys go 40-50. I probably should be more, but no problems so far. Oh and more $$$$. Maxspeeding rods? hmmmm. I wonder when they are going to come out with pistons and billet cranks so people can build race motors on a tight budget.  

[Fredrik_Steen]

You need to change the washers in the head when you use CHN1000K nuts. The stock ones will just deforme and lose claming force.

Ignition curve you need to be abel to controll.

Boostcontroller, you need to be abel to contoll boost around torque max. Torqe kills engines.

I would go for a MSL gasket, not  cooper.

[no class]

….. save yourself some trouble and go with the cometic mls gasket .

[rider384]

Thanks for the help guys! I'll look into having my pistons machined to lower CR rather than using a base plate spacer, along with going with an MLS head gasket. 

10 hours ago, clivegto said:

You need a 2mm base spacer plate which will take the compression down to about 8:1 with your pistons or skim the tops of your pistons, this will also depend on the length of the rods you have. No base gaskets but use a suitable sealer like gaskawich on the spacer plate. Piston to cylinder wall should be about 4thou in my experience. Do a dry build and measure it yourself so you know what you have. 

Thanks for the insight on the piston -> wall clearance, now I have something to tell the machine shop. I'll drop off a piston to work with just for safety's sake. 

5 hours ago, Arttu said:

lots

Good to know about the squish clearance, and good to know about machining the pistons down. I've already decided on going 8.5:1 on the compression since I'll be running California, but wasn't sure what the best way of reaching that CR was. I know I'll have to calculate my CR for myself since different manufacturers rate their CR with different conditions - some with gaskets, some without, some theoretical, etc. 

4 hours ago, Gixer1460 said:

lots

Thanks for the insights on dishing pistons! When it comes to the rods, I know they're a risk, but I know of several people running their rods and pushing high numbers - not in the 1157 world, but the BMW world. I trust their products, the two K04-015s I'm running are maxpeedingrods brand and I haven't had any issues, I've also  run them in my cars in the past with no issues. We'll see about the rods tho. As far as my means/understanding goes, where would the fun in life be if we always stayed within our capabilities? People said the same thing when I built my first turbo kit, then they said the same thing when I LS swapped my E31, and now I hear it about building an engine. Plus, if it blows up, it's an excuse to learn even more when I build the next engine. 

1 hour ago, mikeyd said:

lol! ^^^^ open that wallet. All part #'s correct, use CHN1000K nuts. Heavy duty valve springs too, Titanium retainers, etc... Cylinder boring -81 mm pistons, 81mm bore. Pistons should be 20-40 thou in the hole. I set mine at 20, nitrous guys go 40-50. I probably should be more, but no problems so far. Oh and more $$$$. Maxspeeding rods? hmmmm. I wonder when they are going to come out with pistons and billet cranks so people can build race motors on a tight budget.  

Thank you! I'll order the parts then, I was waiting on confirmation that they're indeed what I was after. I'm assuming the nitrous guys go with 40-50 thousandths to account for the extra heat and expansion of the piston/rings? I'll probably go towards the upper end for the sake of safety, I'll do a bit more research on it. 

1 hour ago, Fredrik_Steen said:

You need to change the washers in the head when you use CHN1000K nuts. The stock ones will just deforme and lose claming force.

Ignition curve you need to be abel to controll.

Boostcontroller, you need to be abel to contoll boost around torque max. Torqe kills engines.

I would go for a MSL gasket, not  cooper.

Luckily I'm already running EFI by way of GSXR throttle bodies and a microsquirt, which I did specifically to gain control of the spark. I believe it is capable of controlling boost as well, but I'll have to look into that. Worst case I get a standalone boost controller. Thanks for the heads up on the washers, I'll add those to my order as well. 

58 minutes ago, no class said:

….. save yourself some trouble and go with the cometic mls gasket .

Good to know. Luckily I didn't pay for the copper one, it came with my pistons. I'll order up an MLS one instead as you and Fredrik have recommended. 

 

Thanks guys, outstanding information to work with, I appreciate all of you.

[no class]

use the piston to wall clearance recomended by MTC …. they will know more about the thermal expansion of thier forged pistons more than anyone else . same goes for the ring end gaps .

[rider384]

Hi all, small update. Started pulling the engine apart and saw nothing obvious that would lead to such an extreme loss of compression. I've attached a picture of the piston from the cylinder that was only making 30psi. Apart from some scoring on the top land, I don't see anything extreme. Ringlands are intact and un-cracked or scored. The head gasket was visually in one piece. Top end looks pristine, no scoring on the cam journal bearings or the cam itself. The rings themselves looked fine as well. Two of the piston pins were a pain in the ass to get out, but I assume that's fairly normal for an engine with 32k miles, 5k of which were at 13psi of boost. 

Anyone have any thoughts? Maybe the cylinder studs stretched and weren't sealing the head properly? Like I said it was a bone-stock unopened 1999 Bandit 1200 engine. I honestly have no idea. Suggestions on next steps? Already planning on taking the head to a machine shop and having them test it and clean it up a bit.

Edit: Oh, and the compression gauge was verified and the test was repeated 4 times, each time with the same results, even with some oil down the cylinders

Edited February 11, 2022 by rider384

[no class]

well….. if the gauge you used was in perfect order….. the pistons are good as you claim… no broken rings…no head gasket damage…. the obvious place to look next is the cylinder head ….. bent valves or damaged seats

[Gixer1460]

10 hours ago, no class said:

use the piston to wall clearance recommended by MTC …. they will know more about the thermal expansion of their forged pistons more than anyone else . same goes for the ring end gaps .

And if the company doing the boring is any good - give them all the pistons and they will bore / hone the barrels to suit each piston and mark them #1,2,3 & 4.

Regarding the piston pictured with some scoring - i'd suspect a degree of crushed lands partially trapping the ring? They aren't the strongest in this respect and its a usual point of failure in boosted engines. Valves may look good but until they are out and checked for straightness, the jury is still out!

[mikeyd]

On 2/10/2022 at 5:23 PM, no class said:

….. save yourself some trouble and go with the cometic mls gasket .

+1 on this!  I use one now, no o-ringing the head anymore, re-used it 3 times already and has seen up to 32 lbs of boost - 0 problems. Cometic is still 2-3 months behind though. 

[Fredrik_Steen]

On 2/11/2022 at 12:23 AM, rider384 said:

Luckily I'm already running EFI by way of GSXR throttle bodies and a microsquirt, which I did specifically to gain control of the spark. I believe it is capable of controlling boost as well, but I'll have to look into that. Worst case I get a standalone boost controller. Thanks for the heads up on the washers, I'll add those to my order as well. 

Good to know. Luckily I didn't pay for the copper one, it came with my pistons. I'll order up an MLS one instead as you and Fredrik have recommended. 

I ordered my washers from Daniel Leander on facebook, he makes for Hayabusa and Bandits. APE doesn't make washers unfortunately.