Gonna drill my 392 for 4 bolt interior mains. With the rear main "severe duty" costing as much as the 3 interior mains together, I am wondering if changing out the front and rear mains are necessary? Block will be .030 over, 8.5:1 forged, .520 lift, 250 duration, 8-71 Ed Pink blower....not sure about carburation yet. I saw many Hemi types on here the other day, so I am sure there are plenty of opinions, I can use them. Motor will live in the 3-6K range on the street. I get the fact that another $500 won't break the bank, but interested in views. Thanks
My personal opinion would be to forego the "severe" duty front and rear main caps and install one of my main cap girdles. The rear caps dont present a problem. And installing 4 bolt center caps only hightens the abuse that the front cap gets. The problem in any of these engines is not weak caps, but cap walk. The girdle is the only way to tie all five caps together. This is Gene Adams Engine Masters engine with my girdle installed.
In my opinion, front and rear mains are not worth the price. Front main; your blower belt will pull the crank up into the block escpically after you have run the motor for a while, as the blower belt tightens, it does not loosen... I shift my blown 392 between 6,500 and 6,700 RPM all day in my nostalgic drag car. Running the car for 3 years with no issues. I am using the center 3 - 4 bolt mains.... You are building a stout street motor, not a drag motor....
Mr Waters: Whos caps did you install on your last EMC Hemi. By the way you guys ( Dan Miller) have my friends Crower Inj. for the next engine. Small world. I want to use your Girdle and will be replacing the 3 centers on my 331 so I will be talking to you sometime about Studs and such. I have fit many aftermarket caps to blocks at my friends (Frontenginedragsters , Pro Formance Specialties) shop and man we could have quite the conversation about this I bet. Those Chinese caps are such junk. Takes lots extra work to get them to fit properly and the Heat treat can be so friged up on them. Was looking at the Pro Gramm caps which seem well made but they look hard as Heck to.... Not thinking the Hard caps are to great on the block but have not got any back that showed any metal transfer. Thinking to just use the Milodons or maybe just make them from scratch. Lots I would love to talk to you about about but will stop short here. Anyway great stuff and good luck on the next EMC thank you Luke
Are you suggesting the girdle in ADDITION to the 4 bolt upgrade in the interior? Great looking engine in the photo, but those mains are more modern than the ones I have, and have the look of Hot Heads 4 bolt stuff. If the answer is no, and the girdle is instead of any 4 bolt arrangement, are there any machining requirements to your girdle? Thanks
For street engines we use studs with stock caps, no issues in last 20 years, including blown 392's and radical 354's. You may be shifting in the 6k range but with most of your driving operations in the 2500-3500 range I doubt you'll need 4-bolt caps unless this is going to see alot of strip use. .
For the majority of engines, I recommend using the stock caps. They are strong, and you rarely hear of a cap failure. Plus I dont like getting into the side webbing for 4 bolt caps. Most of my girdles are installed with a supplied ARP stud kit. Opinions vary on the topic of necessary line boring when using studs vs bolts. So I will word it this way..... when doing a rebuild on a 50+ year old engine, I would opt for a line bore as part of the rebuilding process. Other than that, the only machining I recommend when installing the girdle is spot facing the caps so that all the heights are equal. To be honest, I am not sure what Danny used for caps on the EMC. I was just talking with him the other night about his 2010 entry. The block I am doing now has 1 through 4 billet 2 bolt caps from BCR Products. The Pro Gram caps are good also. A problem I have seen with some aftermarket caps is not only the initial fitment, but the center needs to be side cut for the thrust bearing....something not every shop can do.
Texas Quake, four bolt mains on the center three are defintely lighter than using a girdle. The girdle is the strongest set up and can be fitted to machined stock main caps. The stock front main and rear main are fine, there is no need to replace them. The girdle must be fitted with a preload upon a machined flat surface and alignboring should be done after the preload is set. I have run both the four bolt caps and girdle on stock caps in blown fuel motors on 95% nitro with no cap failure. I have run injected fuel motors with stock 2 bolt mains on 98% nitro with no failures also. The biggest problem lies with getting enough oil to the bearings. I do not reccomend using "street" or p***enger car type oil filters because they are too restrictive and starve the oil system of flow. Bearing clearance compatable with oil viscosity is key. Early Hemis Rule! Goldy
goldy do you mind elaborating on what brand of oil filter system you use? also with a blown street engine with .003-.004.5 bearing clearance would you just run a straight 40w oil? thanks
I guess I will keep this one going. Maybe this thread will go into a tech section. Over the years there have been a variety of "girdles" for early hemis. The most common I would say is the old type which clamped over the center mains and bolted to the pan rails. The tops of the caps were machined flat and the girdle laid across them. You then had to notch the sides of the oil pan. To be honest, I cant see how this deal amounted to anything. Another pretty trick piece I have seen is a complete aluminum girdle and main cap ***embly. I am asked all the time "how much stronger does your girdle make the bottom end?" The answer is none. It doesnt make the main caps stronger. It doesnt make the block stronger. But it does add rigidity....and that is what stops the cap walk. As most who have posted have said...the stock caps are not prone to failure. My 392 girdle weighs 4.25 pounds with the spacers, does not rest on the caps, and fits stock oil pans.
A relatively light 'street' driven hot rod with a hemi, on street tires will not require 4 bolt mains, etc.... Just my opinion..... LZ / Luke: That will be the only time you will see a good reaction time from me... He He He .....
Thanks to all for the exchange. Here are a couple of shots of my starting point. Got this a couple of months ago from a local gear head who put in a great deal of effort in the frame and suspension. I'll post as things go along if you are interested. Thanks.....
Back in the day we just milled them flat and used "Choclate bars" for racing. Never heard of a main problem back then. Certainly not in a street motor The girdles though are a real smart idea if you are at that power level. Don
GOLDY!!!!! Hey buddy!!!!!! Haven't heard from you in awhile!! Good to see you chime in! I know you've been around the block more than a few times with nitro Hemis.
Girdle is the way to go.....if that crank starts trying to walk, those caps are gonna move and the girdle will keep everything lined up and stable....
Since goldy isn't back yet I'll offer a few words on oil wt vs clearance. If you are running 3-4½ thou then you need at least 40wt in order to fill the annular space and provide a wedge for the crank to ride on. The oil is there to cushion/protect/wrap the journal. Light wt oil will not fill the void. Now consider this; NASCAR folks are now using as little as 0.001 and 0-20wt oil. Not many of us punish engines as do those guys. Now, this also requires a very good filter system in order to keep the junk out of the oil. Check the Wix web site, they have alot of info there including details like micron rating of various part numbers. The next issue that must be considered in conjunction with the clearance and oil weight is the style of bearing. If you are going to flog the engine then all three items must be considered as a package. The down side here is that not all bearing materials are available for all applications so some compromises may be needed. I know we have bearing mfgr rep on board, now, where is he...? Sua Sponte
TEX...I believe MR. WATERS gave you not only the best advice, but far and away the best price wise! the man KNOW'S what he's talking about, in my view...POP.
I've seen straps made with a fine-pitch bolt installed in the center to act as a jacking screw to pre-load the cap arch prevent ovalling under load. Needless to say, this is not a subs***ute for a better cap (where the original is not to be trusted), but has anyone seen actual data as to which engines used them (I've heard nailhead?), and especially how much torque is used on the bolt?
I use 60wt Pennzoil or Kendall nitro 70 with .003-.0045 Filter - olberg or system one high flow. Sometimes I run no filter by using a block off plate and a U shaped tube. Really, how much dirt do you expect in five or six seconds? If you have bearing chips you need a lot more than a filter!!! Oil gets changed after the run. Street car - high flow filter!! If you want to run 40wt, tighten up the clearance a bit. Goldy
Great info here guys..... Goldy, what rod main/clearance/oil would you run on a street/strip blown Desoto Hemi on gasoline? This will be used with a hi flow, remote oil fitler element. Panic you are correct about those straps. Tom will be in touch soon re the shafts/girdle/studs. Rat
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