9:1 cr wiseco 85.5mm ptw and ring gaps....

[95DsManiac]

Hey all. I'm having a really hard time to figure this out and make a decision on my ptw and top and bottom ring gaps. I have read about a thousand threads and the posts are everywhere. I would rather ask my own questions and get answers to them. Im running the following:

H1e 58mm same as hx40 8 blade
Running e85
Wiseco 9:1 85.5mm pistons
Eagle h beam rods
ACL race main and rod bearings
Arp mains and rod bolts
Polished crank
6 bolt bottom 7 bolt head
Looking to run 25-30 on the street and 30+ at the track. This is my daily by the way.

So I guess I'm asking what ptw, top ring gap, and bottom ring gap for a daily driving 450-600 hp car.

I don't exactly know if my pistons a coated but they do have the W on the sides with a black background.

I was thinking:

Top: .020
Ptw: .035 so when the black rubs off its closer to .040
Bottom: .022

Des this look right or am I way off?

Any and all suggestions are welcome and hopefully some with close to the same set up can chime in.

Anthony B.

 

[BogusSVO]

H
Looking to run 25-30 on the street and 30+ at the track. This is my daily by the way.

So I guess I'm asking what ptw, top ring gap, and bottom ring gap for a daily driving 450-600 hp car.

I don't exactly know if my pistons a coated but they do have the W on the sides with a black background.

I was thinking:

Top: .020
Ptw: .035 so when the black rubs off its closer to .040
Bottom: .022

Des this look right or am I way off?

Yes your pistons are coated, that is what the black is.

Now if you truly run a .035 -.040 PTW you will never get a .020/.022 ring gap

You should have about .100 - .125 ring gap and suffer horrid piston slap and cracked/ busted skirts before you even get out of the break in stage of the engine you are building.

Now if you run the wiseco recommended PTW of .0035 -.004 you should have no issues getting the .020/.022 ring gaps and not have piston slap

There is an paper in the box of pistons with the factors and the formula for figuring ring gaps.

Also due to your boost levels you want at the track, you may want to open your PTW by .005 -.001 more to allow for bit more piston expansion.

 

[pneumo]

Modern Wisecos recommend .0025 and that's a good starting point. Like Bogus said, for your power level just add .0005 to that, so aim for .0030 Please mind the decimal point.
Your ring gaps look pretty good, .020 top, .022 bottom. If you build it right the coating on the skirts will not wear off, it should come out looking like new.

 

[bradselph]

I did the PTW clearance on mine at .0030 The recommended clearance on my paperwork is .0025, but according to you bogus thats pretty tight?

my rings are set at .0168 for top and .0185 for bottom using the chart supplied from wiesco for street-mod turbo/nitrous at 85.5 bore.

 

[BogusSVO]

I tend to build a little loose, both on ring gaps and PTW.

Lean condition = Heat

Heat = Expansion

As long as your tune and fuel system is dead on, you can build tight/spec

But if anything causes you to go lean, weak fuel pump, low voltage to fuel pump, dirty/clogged fuel filter/injectors, bad/weak alternator or a slew of anything else that can go wrong

Or just being new to tuning and doing a bad adjustment, can send you lean.

A extra .0005-.001 on the PTW, or an extra .002-.003 on ring end gap, could just save your engine, from busted ring lands, or gaulled pistons.

It was the way I was taught, and still the way I build.

Other engine builders have there own thoughts and theories and experience to draw from.

 

[95DsManiac]

Yes your pistons are coated, that is what the black is.

Now if you truly run a .035 -.040 PTW you will never get a .020/.022 ring gap

You should have about .100 - .125 ring gap and suffer horrid piston slap and cracked/ busted skirts before you even get out of the break in stage of the engine you are building.

Now if you run the wiseco recommended PTW of .0035 -.004 you should have no issues getting the .020/.022 ring gaps and not have piston slap

There is an paper in the box of pistons with the factors and the formula for figuring ring gaps.

Also due to your boost levels you want at the track, you may want to open your PTW by .005 -.001 more to allow for bit more piston expansion.

Thanks a lot bogus. So from my understanding I should do this:

Piston to wall clearance: 0.0035
Top ring gap: .020
Bottom ring gap: 0.022

Correct?

Would this be ideal for a 500+ fwhp daily driver?

Thanks again bogus.

Anthony B.

 

[Cdc1221]

P2w clearance of .003-.0035, not .035. .035 would probably send your engine into a rod chucking fit

 

[95DsManiac]

Corrected. Thanks. I always get confused when it comes to decimals. Ill be sure to double check what I post before I post. Hanks again.

Anthony B.

 

[viperlp01]

Please use a torque plate and have the mains torqued. None of these values mean a thing when you torque the head on the block on the outside cylinders shrink by a thou or so. The machinist you pick should be giving you recommended PTW.

 

[95DsManiac]

Ill be calling first thing in the morning to tell him about the torque plate. Thanks for that bit of information.

But what do you think about the clearance and gaps I'm thinking about?

Anthony B.

 

[killercolt]

I highly recommend running .005" ptw for Wiseco pistons. What Wiseco recommends is way too tight for a 4g63t. I am running .007" with no pistons slap. I initially built it to run 100+shots of nitrous but ended up settling on 55 shots. I got over 300+ 8500-9500rpm dyno pulls and 100+ track runs on the engine and it is still kicking hard. Compression on my engine is still 245psi. Last inspection revealed no scuffing or nick on the cylinders or pistons. 005 worked for a lot of engines I built over the year. I never had a come back. Recently I did one at .004" because my friend insisted on it. He is still running one it and had not complain about it yet. Finger cross.

Most machine shops have fxxx up alignment bars from years of use. If it is not brand new, they can not hone or bore your cylinder bore perfectly square to the crank. You will need that the extra clearance to account for that. Some shop reference the bottom of the block when boring the block. If the block has ding and high points, the main bearing bore will not be square to the cylinder bore. Block distortion, block expansion, piston expansion, and imperfect machining should be consider when selecting a safe ptw.

You should ask that you machinist take his time when honing your block. The bore can expand as much as .0005" during the honing process. If he was busy and does not do a final measurement after letting the block cooled down after the honing process, your cylinder bored will not have the spec requested. Feel free to hook him up with a little cash. If he is defensive when you request this, take it somewhere else because he does not care.

 

[BogusSVO]

Killercolt... You do bring up a good point about the shop equipment, mainly about boring bars and stands.

There are 2 basic types, one is the air lift style, a bar fits thu the mains, and then the block if locked under a bore plate, this style is horrid about boring a crooked bore, it sets up off the block deck. So if the block deck is out of alignment with the main bores, you end up with tilted cylinder bores.

Also this style of boring stand makes it difficult to use a torque plate.

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The other style sets up off the main bores and clamps down, some use a main adapter. This style takes a bit longer to set up and level, but, IMHO, is more accurate.

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This style allows the use of a torque plate.

There are variants of this style from Kwik-Way and Rottler.

Both are very heavy bases and will absorb vibration, and little to no flex unlike the airlock boring stands.

Also keep in mind, not all machine shops will have torque plates, some have none, while others will have the common chevy and fords, fewer will have ones for the 4g63

 

[bradselph]

The shop i use is in Orlando and they are top notch with 4g63s they have torque plates for them as well so i have faith in my machinist, if bogus was closer id obviously go to you but im already driving 2 1/2 hours to Orlando.