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4g63 rebuild question

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10+ Year Contributor
Jun 12, 2012
Natrona Heights, Pennsylvania
Ok I have a 95 talon that is 6 bolt swapped. Motor has 130k with no issues but id like to do a rebuild this winter to freshen things up. I plan on putting in new gaskets, seals, bearings, rings and arp heads mains and rod bolts.

My question is, since the motor has no issues can I just take it apart and put the new parts in without machining the rods and crank? I already plan on honing the cylinders and getting the head decked. Any input would be appreciated!
If you end up going with a bigger turbo and running more boost before I get my setup together you gotta keep me updated on compression numbers and how well your HG is holding up. I had a sh** ton of issues keeping a HG on my 30r/G4CS combo when I lived in CO, but I didn't have the technology we do today. As it is I'm still a little nervous. What size Cometic did you go with, the standard gasket or the 87mm one?

Can do. I went with the 86.5mm standard SOHC gasket. The drains in the block are plugged with freeze plugs and copper RTV. Here's the exact one I got:

I can give compression when I check before the dyno. I plan on running the Big 16g as hard as I can, then replacing with a 20G I got for very cheap. The ultimate goal is to go with a Cyclone IM, the FIC 1650s, and an FP Green.
I am planning on breaking my motor in on a Green XL, so our setups will be similar. I do plan to eventually move from there to a twin scroll 60mm+ turbo setup(HX40, HTA 3586R, etc). I'm half tempted just to get an o-ringed head along with the ARP 625+'s and an MLS. If it pops HGs on that setup then I don't know what to do. :p
Well today I got the crank bolted in, I did plastic gauge first then I cleaned and lubed everything and torqued my mains down to 18ft lbs and a quarter turn. I used my old mains is that a big deal? And I used the same sequence as we do for our head studs.


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-6 bolt DOHC main bearing cap bolts are torqued to 49 ft/lbs. Not sure where you got 18 ft/lbs and a 1/4 turn.

-Yes, you can reuse the main caps.

-No, there is no torque sequence for the main bearing caps.

What were your Plastigage readings?
And gst with psi, my readings are wrote down at work ill post them tomorrow, they were in spec though.

Any ideas on what I should do about my torque issue? Should I loosen the mains and re torque them to spec?

And sorry my question was can I reuse the main bolts?

This was my torque reference.
The main bolts are pretty heavy duty, so I'd say you are probably fine. There's not a stretch spec that I'm aware of. Yes, you can reuse them.

The biggest issue is the Plastigage readings you took are inaccurate since you over torqued the mains. You'll need to remove the main caps and re-measure all the journals at the proper torque. You also need to make sure you didn't distort the main bearings when you over-torqued the main caps. If the edges of the bearings look smashed, damaged or mushroomed at all, they are trash.

That link you posted is garbage. You need to look here for now on:
Thank you so much gst with psi, I will remove the crank and re check everything tomorrow. Once I reinstall everything should I torque them to 49 or 66 since they have already been torqued that tight?
You will always torque the mains to 49 ft/lbs. I like to torque them in 2 steps, splitting the spec in half.

I'm not sure how you are checking with your Plastigage, but this is a good photo representation of what to do:

TAKE YOUR TIME! When tiny little things like torque specs get overlooked, you'll be doing this all over again in 20 miles...And paying for everything all over too. If you don't have someone to help you and double check your work, make a list of what you're doing as you work. You can then go back and double check your own work, or even post it up here for others to double check for you. It takes some extra time, but you'll be glad when you're not rebuilding this thing in another 20 miles.
So as for the crank I redid everything just how we talked about and it went great. I also got my new front case in from jnz. Only problem I had was I had to switch the castle plug over from my old case to the new case. Since I didnt have a o ring for it I had to get one out of my o ring kit and use it. Hopefully it dosent leak!


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