Magnus 9.0:1 Ross pistons - question...

[2-0turbo]

Hey all. I am in the process of a 6-bolt rebuild and considering a 4G64 crank with Eagle rods and Ross pistons. JE and Ross (through Magnus) make the pistons with the wrist pin moved to accommodate the longer stroke. I am very interested in this upgrade, but I want to have it reliable long term.

By moving the wrist pin up 6mm, on most pistons this begins to interfere with the lower oil control ring. The guys that stroke Ford 302's to 347's report high oil consumption problems after doing this mod because of the wrist pin/oil control ring interference.

I emailed Magnus to see, since their pistons are "custom" designed, if they addressed this issue by moving the lower oil control ring up some. I got no answer and hoped if anyone here was using these Magnus pistons, they could tell me if this was the case.

Does the wrist pin on the Magnus/Ross 9.0:1 Stroker piston interfere with the lower oil control ring? Thanks.

 

[candela]

I was wondering this to. But even if the oil ring has to be positioned over the wrist pin hole can't you just use roll pin ?

 

[2-0turbo]

Originally posted by candela
I was wondering this to. But even if the oil ring has to be positioned over the wrist pin hole can't you just use roll pin ?

Retaining the wrist pin is not the issue. Not having the oil control ring fully supported on the back side is the problem--as I understand it. This may not be a big issue, but my Mustang buddy tells me the Ford guys run into this all the time. Some have big problems with oil consumption, others have none. Those that have it with the 347 motors blame this lack of support. The theory is reasonable since a 302 motor with the stock pistons doesn't have the oil burning issues.

 

[swordfish]

He is a side view of my Ross pistons for my long rod 4G64. They are a little different than the 4G64/4G63 hybrid pistons. As you can see, the pin is also offset forward from center. These were made to set atop a custom made set of Pauter rods that are long than the stock 150mm length. Ross Side View So yes, the wrist pin is all up in the oil ring. Pins are held by spiroloks and there are no buttons. Marco makes sure to send you oil rings and oil ring supports to make everything work properly. I wouldnt worry about longevity or oil consumption if your builder has his head on straight. There are some more pictures of the pistons in that directory if you are interested.

jeff

 

[candela]

So then what is your alternative if Magnus doesnt make anything? Thick lands and maybe trying to get a cast iron portion of the oil ring to try and keep corret tension all the way around, getting as small a gap with as less compromising as possible of the rod... what rings are you thinking of using anyway? How big of a gap is it behind the ring? I have heard about the 347 strokers before, and it seems that either some say its fine or some go other routes like a 331 with a shorter rod, which give more than enough clearance for the pin to fit below the oil rings....

If you do talk to Magnus and see if they have custom pistons made, Im curious as to how durable the ring lands will be when a little detonation happens Swordfish, how long have you had the settup in for? Have you noticed anything about oil consumption? I'm sure that Marco prolly knows what hes doing, and with the proper support and rigth rings Im sure it would even be ok to have that much gap....but then again noones really been driving these everyday for a while now as they are fairly new!


Austin

 

[2-0turbo]

Jeff, I know the 4G64 pistons ARE different than the stroker 4G63 pistons. The 4G64 block has the higher deck height, so you don't have to run "short" pistons to prevent from hitting valves/head. But, you said you are running longer rods, so I digress--I'm not sure where that puts you. How much longer than stock rods are you running? I am my own engine builder, so I cannot rely on someone else to pat me on the butt and tell me it will be alright. This might not be a big deal, but I'm putting a bunch of money into my engine and I would like to think it is going to last me 100K miles before I need to tear into it again.

Austin, if I decide not to go with these pistons, my alternative is to build a standard 2.0 liter 4G63 and not stroke it. I would use whatever rings Magnus provides with their pistons. My reference to the "custom" piston thing is from their website. They claim you cannot buy these pistons anywhere else, that the are made exclusively for Magnus. Probably true--not that hard to have custom pistons made this day and age.

 

[swordfish]

As for the Magnus custom pistons. You are looking at them for the long rod 4G64. The pistons for the 150mm rod look like these with the exception of wrist pin location. It took a little over a month from the time I ordered the pistons from Marco to the time they arrived.

The rods are 156mm Pauter. So they arent much longer than stock. Rod ratio is now 1.56:1 which is slightly better than the 1.50:1 with the stock 150mm rod. Detonation is not going to be a problem for these pistons, they are thick and if I detonate bad enough to damage one of these, then I need to just give up because I dont know what I am doing.

My setup isnt even up and running yet, as I have had to wait 4 months for Pauter to custom build the rods for me. There are 3 sets of these rods in existence as of right now. A set for me and 2 sets for Marco. Although, Marco promises they will become more available as Pauter gets faster at making them. They just shipped from Pauter on Wednesday the 25th. The car will be up and running by August and is going to be a daily driven car. If I didnt trust that the engine would hold up, I would not be building it. If there is a weekness though, I will find it. The goal is 600whp, look stock, and have AC and PS. I've already been able to coax 473whp out of a 7 bolt with 1G rods in this car so I only have 127whp more to go. But this time I have the help of .4 more liters and a huge turbo, and nitrous, and anti-lag.

Sorry, got a bit off topic there.

jeff

 

[RuBiCaNT5X]

*Pats Matt on the butt* "You're doing a good job!" Sorry for the non-related content, but I got faith in ya, bro.

 

[2-0turbo]

Jeff, you mention that "Marco makes sure to send you oil rings and oil ring supports to make everything work properly".

What are the oil ring suppports? The oil control rings I have seen are three piece: scraper, metering, and scraper--all sandwiched together. Does Marco provide something that goes behind the oil ring to provide support over the wrist pin hole?

I have emailed and called Magnus and didn't get answers from either. Anyone know where they are at? I would really like to get an answer on this and not just "Don't worry about it." Everything I have seen leads me to believe that this can potentially be an issue for high oil comsumption. If someone can tell me "We have run this engine for XXX miles with no problems", that is the empirical evidence I am looking for.

 

[swordfish]

I am calling the scrapers oil ring supports. What you mentioned above is what you get.

jeff