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Smart quod bastardus
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changing rod bolts and bearings without splitting the case
Has anyone ever replaced rod bearings and rod bolts on the 3.3 without cracking the case?
I am trying to avoid a complete teardown and extra expense of seals and main bearings when splitting the case when my goal is to replace the rod bolts and rod bearings during my top end rebuild. The bottom end is pretty indestructible on the 930 except for the rod bolt weakness that most guys are aware of now, when Porsche switched to 9mm rod bolts. I just dont know how many guys have taken this approach and how difficult it was to replace and measure the rod bearing clearance with the case together. I plan on using plastic gage tape to measure rod bearing clearance if i can get in there....thats the question. I dont have an engine stand and am on a tight budget so cracking the case adds alot to my bill if I dont need to do it. Engine has at most 104k miles on it going by my odometer if it has never been rebuilt before. But being the 4th owner I dont know if the bottom ends been rebuilt already or not. Evidence of heavy case sealant indicates it may have.
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1979 930 Turbo....3.4L, 7.5to1 comp, SC cams, full bay intercooler, Rarlyl8 headers, Garret GTX turbo, 36mm ported intakes, Innovate Auxbox/LM-1, custom Manually Adjustable wastegate housing (0.8-1.1bar),--running 0.95 bar max ---"When you're racing it's life! Anything else either before or after, is just waiting" |
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11-09-2010, 01:10 PM
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Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,894
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did it both ways the first time was without splitting the case. The second i split the case. splitting the case isnt hard and it's easier to measure the stretch on the bolts. I used arp rod bolts and instead of a torque value they have a stretch value which is hard to measure with the crank still in the case. so i torqued each one on the rod outside of the engine to get the correct stretch, then took the bolt out and put the rod on the crank then torqued each bolt to the same torque needed to get the right stretch. couple years later when i pulled it apart for broken rings and split the case i measured them all and the stretch was correct on every one of them.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's. 2019 Silverado 6.2L |
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11-09-2010, 05:00 PM
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Join Date: Aug 2008
Location: S. Florida
Posts: 321
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Most will say that it is impossible to change the rod bolts and add Raceware or ARP rod bolts without splitting the case because these require a big stretch gauge - and they are right. However, if there is a will, there is a way. Made this gauge out of an old micrometer. Took it to a machine shop and tested it against a high dollar gauge - perfect reading on both. Fits right in the case and can measure the stretch of the ARP/Raceware bolt precisely. Problem solved.
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11-09-2010, 05:24 PM
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Registered
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,894
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yeah i had to borrow a micrometer from work and they would not have found it at all funny if i had cut it up and rewelded it .
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's. 2019 Silverado 6.2L |
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11-09-2010, 05:40 PM
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Join Date: Sep 2006
Location: scotland
Posts: 248
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I have mentioned this previously in a post, i have developed a way of doing this without splitting the case to confirm the stretch is correct when installing new bearing and conrod bolts..
You can squeeze digital calipers(verniers) in there and zero them with the zero button on them,then when you remove the calipers from within the crankcase it dont matter if you alter the size reading displayed(e.g hitting them off the case halves when removing etc) as you just close shut the calipers with this size you can then calculate the stretch. Hope this makes sense.....late at night over here in uk and maybe not explaining it too clearly.
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SP Autobahn www.spautobahn.co.uk Porsche inspector for Peter Morgan UK http://www.porscheinspections.com/ "92" 964 turbo,Modified and recently rebuilt using all ARP hardware.. Purpose built fuel controller set up to acheive perfect fuel curve on CIS inj. Last edited by stup; 11-11-2010 at 03:01 PM.. |
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11-11-2010, 02:11 PM
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Join Date: Oct 2003
Location: Mount Pleasant, South Carolina
Posts: 14,273
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I installed mine with a stretch gauge while the crank was on a bench, but after installing the crank in the case, I decided I wasn't confident in what I had done, so I re-installed new rod bolts while it was installed in the case using the alternate method or torque/extra turn?
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11-12-2010, 08:38 AM
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HOW DO YOU GET THE RODCAPS and bolts OUT?
Sorry for reviving this thread but am attempting rod removal on a NA 3.2 without cracking the case
it simply seems there is no room to do this ..do they come out the opposing cylinder? vey confused please email me if you have solution or post thanks frank rauscher@wistar.org |
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03-01-2013, 02:47 PM
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Herman the German
