I have a block that has been bored out and has some deep scratches in the cylinder walls. Boring it again will put it well over the legal limit for an IT block. Is it legal to sleave the block back to stock size? Or should I just dispose of it?
Printable View
I have a block that has been bored out and has some deep scratches in the cylinder walls. Boring it again will put it well over the legal limit for an IT block. Is it legal to sleave the block back to stock size? Or should I just dispose of it?
I recently asked the same question of a "top" mechanic and was told that the thickness of the web between the cylinders of modern engines is not enough to allow the overbore necessary for a sleeve. I know we did this years ago on big beefy blocks.
------------------
Wayne Briggs
CenDiv
ITA Capri
Move...Lest Ye Rust!
This block is 50 over and there are gouges in the cylindar walls that are several thou deep. Guess it is time to retire it.
jhooten, what kind of vehicle?
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit (Bent)
http://linerud.myvnc.com/racing/index.html
85 Supra with a 5MGE
You can certainly sleeve that puppy. However, considering the cost and effort involved, you would be much better off scrounging up an unmolested JY short block.
I guess I could put it back togeather with all my bad parts and use it for a core. http://Forums.ImprovedTouring.com/it/biggrin.gif
I don't see any provision in the rules for legally sleeving a block.
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Geo,
So would this be one of those if it does not say you can, you can't type of things?
That would be my take on it.Quote:
Originally posted by jhooten:
Geo,
So would this be one of those if it does not say you can, you can't type of things?
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Hey are you in Texas? If so where? I saw you post about the school at TWS.
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
My mailing address is in Paige, 25 miles east of Austin on 290. I would have put that post in the SWDiv forum but was afaid no one would see it.
Baring any unforseen circumstances I will be at the Jan weekend in my (as yet to be determined what color) ITS 85 Supra. I have yet to run a race, therefore I don't have a permanant number yet, just look for the only OLD Supra.
BTW, I am still holding out hope that they will find room on the schedule to squeeze a RR in for us at the double nat in Feb.
[This message has been edited by jhooten (edited December 27, 2003).]
The NN schedule is real tight on time, they have a hard time just getting the Nationals in. They quit doing RR's there a few years ago.Quote:
Originally posted by jhooten:
BTW, I am still holding out hope that they will find room on the schedule to squeeze a RR in for us at the double nat in Feb.
Hmmm, some blocks can't be machined (e.g. Alfa's) and *must* effectively "sleeve" the block to get the allowed overbore (or even clean up the stock bore). I've never heard of that being ruled illegal.
That forms my basis for believing that sleeving any block would be an acceptable way to set the bore to the legal limit. I don't see anything in the ITCS that disallows sleeving. So, why wouldn't it be included in the currently allowed engine prep up to the limit of .040" overbore?
Wouldn't you need to go by the manufacture's recomendations for "rebuilding" a motor to the next standard bore?
Just like for body repair?
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit (Bent)
http://linerud.myvnc.com/racing/index.html
I'm not sure that the manufacturer's recommendations apply as stictly to engine "rebuilding" since we're also allowed "blueprinting", which is, by definition, more than the factory "recommends"... Also, what do we do if the manufacturer "recommends" repairing a block that's already .040 over by boring to .060 over, if sleeving weren't an option?Quote:
Originally posted by racer_tim:
Wouldn't you need to go by the manufacture's recomendations for "rebuilding" a motor to the next standard bore?
Just like for body repair?
[This message has been edited by Eric Parham (edited January 15, 2004).]
I don't see any argument there that would make sleeving. If the book doesn't say you can do it, you can't. Just because you can't overbore the block doesn't mean you sleeve it to do so.Quote:
Originally posted by Eric Parham:
Hmmm, some blocks can't be machined (e.g. Alfa's) and *must* effectively "sleeve" the block to get the allowed overbore (or even clean up the stock bore). I've never heard of that being ruled illegal.
That forms my basis for believing that sleeving any block would be an acceptable way to set the bore to the legal limit. I don't see anything in the ITCS that disallows sleeving. So, why wouldn't it be included in the currently allowed engine prep up to the limit of .040" overbore?
I'm not sure that the manufacturer's recommendations apply as stictly to engine "rebuilding" since we're also allowed "blueprinting", which is, by definition, more than the factory "recommends"... Also, what do we do if the manufacturer "recommends" repairing a block that's already .040 over by boring to .060 over, if sleeving weren't an option?
It doesn't matter that blueprinting is allowed. It's specifically spelled out that you can overbore. But it doesn't say you can sleeve your block. No way.
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
AFAIK, there is no such process as "overboring" (yes, I checked my dictionary). An overbore (noun, not verb) is only a result. Now, what are the allowed means to obtian that result (i.e., the "overbore")? I'm saying, if only for the sake of discussion here, that any means can be used to obtain the allowed overbore (noun here, not verb).
Some of those means might include, for example, boring (not "overboring") with a boring tool in a machine shop (typical), using some futuristic laser to fashion the bore (not so far-fetched), using a repair process that melts and recasts the bore (too expensive), or using a sleeve. A sleeve merely replaces a wear surface, right? Unless it's specifically called out by the GCR as an unacceptable practice, why wouldn't it be allowed? Sleeving is certainly a well-known and generally accepted method of repair to obtain a desired bore size. That's why we already know exactly what it means, right?
Now, to call my own bluff, perhaps a sleeve would be catagorized as a coating, in which case it *would* be specifically disallowed. But my current understanding is that a coating is only a powder or liquid.
I think there's also reference in the GCR to not adding material that was not originally present. But, the worn-out material that a sleeve replaces *was* originally there.
Finally, for possibly the weakest of my arguments, we all know that bearings can be replaced as a matter of course. Many engines have other wear surfaces where a bearing should have been used but was omitted for cost reasons. I don't know, but some have said that a bearing may be installed (perhaps if spelled out in the shop manual, or maybe otherwise) if one of those surfaces gets galled. Isn't that basically what a sleeve accomplishes after a broken ring galls up a cylinder bore?
IANATI, but I cannot imagine it being legal unless it is called out in the FSM as the proper method to repair/resurface a bore.Quote:
Originally posted by Eric Parham:
Now, to call my own bluff, perhaps a sleeve would be catagorized as a coating, in which case it *would* be specifically disallowed.
I think that's a stretch. That's almost like calling a turbo an exhaust manifold.Quote:
Originally posted by Eric Parham:
I think there's also reference in the GCR to not adding material that was not originally present. But, the worn-out material that a sleeve replaces *was* originally there.
Only if the sleeve was in the block originally (the way I see it).Quote:
Originally posted by Eric Parham:
I don't know, but some have said that a bearing may be installed (perhaps if spelled out in the shop manual, or maybe otherwise) if one of those surfaces gets galled. Isn't that basically what a sleeve accomplishes after a broken ring galls up a cylinder bore?
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
so wait, let me see if I got this right. I build Vegas and I can't sleeve the blocks? There is no curent process that allows the zinc/iron plating on the pistons like what was stock. I cannot run aluminum pistons because of the aluminum bores. I have to have a dissimilar metal. I cannot coat the pistons with any polymer type coatings, so where does this leave me?
The later factory service manuals offered sleeving with iron sleeves as an appropriate procedure so the dealers would not have to maintain expensive lapping kits for a dying breed.
dang, maybe I should just buy a CRX...
Britt
------------------
Soon to be SSC Mazda MP3
Vintage Cosworth Vega
Guys I would be happy to have anyone of you protest my sleaved block. This is a standard machining practice. Simple as that there is no performance advantage. Only an over anal reading of the rules could keep you from reading it any other way. Engines may be bored.040 over standard bore size. good enough make sure you meet this spec.
You sure about that? There are Porsches, BMWs, and Mercedes that run the same sort of thing.Quote:
Originally posted by 122 Vega:
There is no curent process that allows the zinc/iron plating on the pistons like what was stock.
I guess it would be legal then. http://Forums.ImprovedTouring.com/it/smile.gifQuote:
Originally posted by 122 Vega:
The later factory service manuals offered sleeving with iron sleeves as an appropriate procedure so the dealers would not have to maintain expensive lapping kits for a dying breed.
------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
I loved my Vega even though when you pulled into a gas station the routine was to fill the oil and check the gas.
And don't forget you had to fill the radiator back up too. I had as much steam out the tail pipe as a did oil smoke. All in all The Vega was one of my favorite cars.
Mine never passed coolant although it popped a rad once.
I put over 145,000 miles on that sucker in 8 years and sold it for $90.00
The body rust was tragic.
Cheers.
Ohh...I get it, you don't get protested if your car breaks down after three laps...
I'm immune to protest!
Britt
------------------
Soon to be SSC Mazda MP3
Vintage Cosworth Vega
There were plenty of sleeved vegas out there as it was the dealer performed repair and factory authorized.