Main Cap Question

[Sy Guy 0024]

Is it common for our main caps to become distorted or stretched? I took my block to the machine shop today, and the machinist takes one look at my center 2 caps and tells me they can't be reused because they are distorted (they supposedly wouldn't seat right against the block). They looked OK to me, but I'm definitely no expert.

I ask him what he wants to replace them with, and he tells me he has some good SBC caps to replace them with. I ask him if they are as good as our nodular caps, and he tries to tell me that standard SBC and all 4.3 are the same. I argue that syty caps are indeed a stronger nodular iron, but he tries to assure me that his caps will hold up fine.

Any thoughts on this? :dunno:

 

[dgoodhue]

Re: Main Cap Question

Is it common for our main caps to become distorted or stretched? I took my block to the machine shop today, and the machinist takes one look at my center 2 caps and tells me they can't be reused because they are distorted (they supposedly wouldn't seat right against the block). They looked OK to me, but I'm definitely no expert.

I ask him what he wants to replace them with, and he tells me he has some good SBC caps to replace them with. I ask him if they are as good as our nodular caps, and he tries to tell me that standard SBC and all 4.3 are the same. I argue that syty caps are indeed a stronger nodular iron, but he tries to assure me that his caps will hold up fine.

Their are some nodular SBC main caps, but the common ones are not. I haven't heard of any distorted nodular main caps, but I imagine they do get damaged with engine failures from time to time.

 

[0260IN3]

Re: Main Cap Question

the caps are ususally not the problem, it's the register that holds it in the block. The cap no longer fits tight and will walk side to side. This is common with and 2 bolt main engine block that has seen detonation or high rpm or a long peroid of time. I have never seen sbc with a nodular cap except a bowtie block, so I would be concerned about what your guy is saying.

 

[autoaddictions]

Re: Main Cap Question

Buy the Pro Gram mains and have the block splayed. Costs about 500 bucks for the PG caps and the machine work to fit them. Its money well spent to increase the strenth of the bottem end. If your staying with a stock build forget previous advise!!

 

[Sy Guy 0024]

Re: Main Cap Question

Well great, I don't know what to think. It's hard for someone like me to argue with a guy that's been building race motors forever (granted, not syty motors...). I wish I was more familiar with bottom end components...and had enough money to just order up a Campbell or RPM longblock and drop it in with no worries.

I had considered the 4-bolt upgrade and was quoted $550 to do the work. My build isn't stock, but it isn't too crazy either. Pt-54, Vortecs, 412 cam, etc. Shooting for high 11s/low 12s....and was told 4-bolt was probably overkill.

So let me ask this. If he does insist on using his SBC caps, SHOULD they hold up in this build given no detonation etc...? Just how much stronger are the nodular caps vs non-nodular? I'm getting paranoid now.

 

[James Thomas]

Re: Main Cap Question

Hmm..... No offence to "your guy" but if he is not up with the SyTy engines and the fact that he wants to argue with the customer about going with a heavy duty replacement, I think you need to politely just tell him that you need to save up some more money, collect up you block and parts and go find another shop. "Standard non-nodular" caps, if that is what he is telling you he wants to use are not as strong. You say you are " Shooting for high 11s/low 12s....and was told 4-bolt was probably overkill"??? I disagree. Vortec's a 412 and PT-54 are more than enough to totally waste a stock bottom end. If you have the engine down for a rebuild now is the time to by as much insurance as you can afford. Now is not the time to go the opposite direction and throw weaker than stock parts at it just because your "old school guy" doesn't know the deal with our engines!!!! I am really wondering why he is dead set against going with a cheaper (weaker) part when the correct answer should be "sure why not, because it can't hurt and may just save our engine in the event of a oopsie!". I mean are you paying the bill or is he doing this for you for free and is just giving you the stuff he has laying around in the shop?

If you really want to shoot for 11's I would cryo the crank and do the 4 bolt mains on any thing below a low 12 (that’s me only wanting to do it once and not scatter a whole engine for round three to do right though) . As far as strength, heavy duty / extra insurance parts or processes go like engine coating’s and cryo treatment, I am very leery of "experts" that I have to tell "ok, it may be overkill but that's what I want because I'm paying for it damn'it".

Find another shop..... unless you can 100% assure your self that you will never ever ever push it just a little to far, try to get just another couple of tenth's out of it, runs just 2 more lbs. of boost, ever get a tank of bad gas while your hammering it or never have any type of minor mechanical glitch like a fuel pump, regulator, wiring problem etc. etc. etc.

Now the fine print: May cost more money / cause a divorce, not for everyone, your results may vary, use at your own risk, all sales final, may cause cancer in the state of California and may not be suitable for children under the age 15, please consult your physican.... oh did I mention may cause anal leakage and or uncontrollable nose bleeds? :rotf:

___________
James

 

[sytyguy]

Re: Main Cap Question

If the SBC nodular caps that he's suggesting were GM caps, I'd assume they'd be stamped with an N like our nodular caps are. Otherwise, they're grey iron like used in just about every standard duty GM block around (including the CPI/TBI 4.3L). Contact some of the builders on here and see if they'll part with some stock SyTy nod caps in good condition or either go to the ProGram ones. You'll need to have a line hone done either way.

Hood

 

[Sy Guy 0024]

Re: Main Cap Question

Thanks for all the feedback guys. I hated to spend the money on it, but I decided to go for the 4-bolt billets. :rock: Just didn't feel comfy using the standard SBCs after reading the comments.

Now to see if I can get a 3rd mortgage to finance the rest of this build.

 

[Tooky]

Re: Main Cap Question

I think you did the right thing. I bet you'll have more peace of mind.

 

[Quickstop [UK]]

Re: Main Cap Question

I am doing the same on mine - are you going to cryo your crank as well? What are people's thoughts on it?

 

[Sy Guy 0024]

Re: Main Cap Question

I had to draw the line somewhere, so I skipped the cryo treatment. Like Tooky, I'm converting to Vortecs now and am spending enough $$ as is. But I've been real happy with the Vortecs on my Sy, and couldn't stand to put the stockers back on...otherwise if I didn't have my hands so full and my pockets so empty, I might have looked into it further.

 

[James Thomas]

Re: Main Cap Question

You guys NEED to do this now while you are down for the rebuild. It's not that expensive and damn well worth it..... so that's what I think of it. I mean really, so it costs a couple hundred to do it, even if you have to wait another several weeks to finish the build to pay for it. It's like going to a serious hot chick, meat market pick up bar..... what good is it too even go there without "protection" cause you surely don't want to get "lucky" without it!!!

______________
James

 

[Quickstop [UK]]

Re: Main Cap Question

is it proven to be stronger with cryo though?

I am getting the billet mains from RPM as well and want to make this bottom end bullet proof. All I need now are the rods.

Is there any documented evidence that cryo works well? There is a place here called Frozen Solid that advertise but I guess I am a little unsure - like you say though, if it does no harm then it is probably worth doing....

 

[Tooky]

Re: Main Cap Question

Quickstop[UK], you're my kind of guy. I came across tons of your post when I've been searching syty.net archives for assistance on my head/cam swap. Always very useful. And I think the same way you do - I want to see the evidence to prove that cryo is a legitimate technology. When I tried searching I came up short, to say the least. In fact, John Waller told me he doesn't treat his cranks whatsoever, not even nitriding, and hasn't had any problems, even with his 300,000 mile crank in his Typhoon. I think as long as you don't detonate the crank will hold 700+HP but I won't know for sure until I get to try it with mine.

 

[James Thomas]

Re: Main Cap Question

It's proven. Search Mil-Spec treating process's, NASA, cryogenic tempering etc. Also if you NEVER detonate and or NEVER push it to far, Tooky's prolly right (also won't need those 4 bolt mains either), you may never have a problem. Question is..... do YOU fit that description? I know I and most other don't for sure. It's just insurance is all. Ask George Blake about what Cryo can and will do, he treats alot of his tranny parts to be "bullit proof".

__________
James

 

[Robert Lone]

Re: Main Cap Question

Cryo does work and I'll leave it at that.

However, from a previous post, I just had my stock block splayed and I sleep better at night.

 

[Quickstop [UK]]

Re: Main Cap Question

these are who I am looking at going to with the cam...

www.frozensolid.co.uk/

here is someone else...

www.engineeringtalk.com/news/cge/cge100.html

If I am convinced...90% there