LSX cylinder wall length?
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
We installed Weisco pistons that had a ring package that allowed a sliver of the pin bore to protrude past the upper oil scraper. I was told by Weisco that there would be no problem running these. We prepped the cylinder bores very carefully making making oil consumption a high priority. The engine burned a quart every 200 miles. It also filled the catch can. We'll have the engine back this week and take a closer look at it.
Below is a pic of the relationship between the oil ring land and the pin bore. We used a napier second ring in this ring package.
I'd appreciate any comments about this.
Richard
Below is a pic of the relationship between the oil ring land and the pin bore. We used a napier second ring in this ring package.
I'd appreciate any comments about this.
Richard
The customer wanted to run a boosted setup. We set the compression just under 9.5:1. I pointed out my concerns when the pistons were ordered. I didn't tell them how to build the ring package. And this is what I got. When I questioned them on the finished part they insisted that they make pistons like this all the time. Furthermore they wouldn't take them back or remake them. Reluctantly we assembled the engine taking every precaution to to eliminate oil consumption. We kept clearances to the minimum. The engine only ran in N/A mode. There was never a blower or turbo installed. It pretty much drank oil from the start. It ran for 3000 miles before the customer decided to pull the engine.
Next time I'll stick to my experience.
Richard
Next time I'll stick to my experience.
Richard
Hey Richard! If memory serves correctly my 422 (4.100 x 4.00 w a 6.125" rod, .940 wrist pin and diamond custom pistons) looked similar to your pic (not as extreme though). However, I did not have any oil consumption problems.
TECH Regular
Joined: Feb 2006
Posts: 437
Likes: 2
From: Cleveland
We installed Weisco pistons that had a ring package that allowed a sliver of the pin bore to protrude past the upper oil scraper. I was told by Weisco that there would be no problem running these. We prepped the cylinder bores very carefully making making oil consumption a high priority. The engine burned a quart every 200 miles. It also filled the catch can. We'll have the engine back this week and take a closer look at it.
Below is a pic of the relationship between the oil ring land and the pin bore. We used a napier second ring in this ring package.
I'd appreciate any comments about this.
Richard
Below is a pic of the relationship between the oil ring land and the pin bore. We used a napier second ring in this ring package.
I'd appreciate any comments about this.
Richard
The practice of running the pin bore into the 3rd land is a last resort...only to be done if there isn't enough room for necessary dish volume or there isn't enough left over ring land thickness to support the horsepower (big nos, supercharged, etc). In racing applications, it's better to have oil consumption than piston breakage. Was I the person you consulted with at Wiseco about these pistons? If so, we haven't had negative feedback on the "pin in the 3rd land" previously, but email me at bnutter@wiseco.com and we'll see if we can get to the bottom of it.
-Brian Nutter-Wiseco Piston
FormerVendor
Joined: Dec 2005
Posts: 250
Likes: 1
In a set-up where the oil groove breaks completely through the pin hole like that a pin button is what we usually use with success. It's not my favorite thing, but doesn't allow the oil to get above the oil ring. Maybe someone has already tried them in an LS1 4.100 + stroker set-up and can comment.
TECH Regular
Joined: Feb 2006
Posts: 437
Likes: 2
From: Cleveland
I talked to Richard on this this morning. The original engine was boosted and had nitous before and had problems. For the 2nd build, the engine ran Wiseco's and piston was designed for boosted AND nitrous usage...-18cc dish necessitating the extra thick lands. A quart every 800 quarter mile runs is permissable, but a quart every 200 miles on the street is tough to deal with. The engine is now being built with a 4" crank with normal piston with the conventional pin placement.
For guys reading this thread thinking about a 4.100/4.125 crank; the 1.050 compression height piston with mandated .237 top and .140 2nd land (with standard pin placement) is fine on the street with mild boost. As long as the skirt shape is ok, oil usage shouldn't be bad. Guys running nitrous should limit it to a very small shot or go back to a 4" crank.
For guys reading this thread thinking about a 4.100/4.125 crank; the 1.050 compression height piston with mandated .237 top and .140 2nd land (with standard pin placement) is fine on the street with mild boost. As long as the skirt shape is ok, oil usage shouldn't be bad. Guys running nitrous should limit it to a very small shot or go back to a 4" crank.
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Verdad Gallardo FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
In a set-up where the oil groove breaks completely through the pin hole like that a pin button is what we usually use with success. It's not my favorite thing, but doesn't allow the oil to get above the oil ring. Maybe someone has already tried them in an LS1 4.100 + stroker set-up and can comment.
I have used several like that with the oil rail a little through the land with no problems or oil consumption. On mine the ring stack was shorter though and there was more slirt in the bore at BDC and I used a longer rod or it was on something with a longer sleeve etc. The stroker pistons I get from Wiseco and I always deal with Brian Nutter above have never had any issues at all but we did really take care in designing them and like was said on extreme power adders and with that shorter cylinder I usually use the 4.00 or even 3.900 crank on those.
I even have some larger stroke stuff in the iron blocks now we are working on that are NA only but seem to work great. They make even more tq and hp but the ring stack is too short for any big power adders at all.
