Lew91 Posted October 31, 2012 Share Posted October 31, 2012 I'm currently at the beginning of forging my spare engine and need a few questions answered if they can be. 1) I will be having the crank micro polished but will I need to have it balanced with the forged rods and pistons? ( are they lighter then standard) 2) will I need to have the shells matched to the crank or is it a simple pop them in and job done?3) is it worth replacing valves and springs whilst I'm there? 4) what piston size is best? Looking to get the block skimmed and reboard any way. Got a few other unanswered questions but I'll figure out this lot first lol. Cheers Lewis Quote Link to post Share on other sites
Idrees Posted October 31, 2012 Share Posted October 31, 2012 1) I will be having the crank micro polished but will I need to have it balanced with the forged rods and pistons? ( are they lighter then standard) It's best to have the full bottom end balanced together. Crank, pistons, rods, flywheel, clutch, crank pulley. Basically everything that attached to the crank. 2) will I need to have the shells matched to the crank or is it a simple pop them in and job done?Ask the machine shop to measure the crank journals while they have the engine. They will advise what size bearings of require. 3) is it worth replacing valves and springs whilst I'm there? A good chemical clean of the valves and springs will do the trick nicely. Of course the valve seals should be replaced (included with full engine gasket set). 4) what piston size is best? Looking to get the block skimmed and reboard any way. Standard size is 74mm, 74.5mm is the most common choice with forged pistons. Of course you could go for 75mm however if the block ever gets scored (heaven forbid) then you'd need to replace the block. If you're using 74.5mm then you could just have it rebored for 75mm pistons. RegardsIdreesID-Workz Quote Link to post Share on other sites
Socks Posted October 31, 2012 Share Posted October 31, 2012 I'm currently at the beginning of forging my spare engine and need a few questions answered if they can be.1) I will be having the crank micro polished but will I need to have it balanced with the forged rods and pistons? ( are they lighter then standard)2) will I need to have the shells matched to the crank or is it a simple pop them in and job done?3) is it worth replacing valves and springs whilst I'm there?4) what piston size is best? Looking to get the block skimmed and reboard any way.Got a few other unanswered questions but I'll figure out this lot first lol.CheersLewis1, Balancing is always a good idea. Wont make much difference to performance.... But will stop accelerated wear and give the engine a much longer lifespan! 2, All the tolerance should be checked to make sure there to spec yes!3, Valves and springs are not somthing that generally needs doing... Stem seals would be a wise move as would re-grinding in the valves and de-coking them tho!4, 74mm is standard. Its always wise to go up to 74.5mm to get a nice fresh surface for the new pistons and rings to bed into!Hope this helps! Quote Link to post Share on other sites
Lew91 Posted October 31, 2012 Author Share Posted October 31, 2012 (edited) Brilliant cheers for the help fellas, I'm hoping to get down the machine shop on Friday and see what they can do for me. I'm going to be getting it all chemically cleaned any way and valve stem seals will be replaced to. Whilst I remember, socks what clutch/ fly wheel set up are you running as any set up that can handle the power yours is putting out is definatly worth investing in?Edit: also idrees can you get the valve spring caps? Just had a look over mine and I'd say they need replacing to. Edited October 31, 2012 by Lew91 Quote Link to post Share on other sites
Lew91 Posted October 31, 2012 Author Share Posted October 31, 2012 A couple more Q's 1) Is it worth having the head ported/polished as I've heard a few horror stories about it? 2) I'm presuming the torque settings on all the bolts are going to be the same as standard? Would they still be the same with ARP bolts tho? Cheers Lewis Quote Link to post Share on other sites
Idrees Posted October 31, 2012 Share Posted October 31, 2012 1) Is it worth having the head ported/polished as I've heard a few horror stories about it? If you have a good job done then it would be a good idea to help spool up2) I'm presuming the torque settings on all the bolts are going to be the same as standard? Would they still be the same with ARP bolts tho? ARP bolts have different torque settings. The bolts have the spec sheets included so you know what to torque them up to. Quote Link to post Share on other sites
Lew91 Posted October 31, 2012 Author Share Posted October 31, 2012 Aha brilliant, mega help. Time for me to get busy then Quote Link to post Share on other sites
AdamB Posted November 1, 2012 Share Posted November 1, 2012 I wouldn't advise running standard size 74mm pistons, as by the time the bore is honed, you could be looking at quite a large clearence that will never be filled unless running on track where you will see high temps and the rate of expansion of the metal changes.I wouldn't waste money getting the head ported and polished unless your looking to run a very big setup. People have run 300whp on a stock head with no problems, so flow is not a problem. Quote Link to post Share on other sites
Lew91 Posted November 1, 2012 Author Share Posted November 1, 2012 I was going to go for the 74.5 any way just so it's all a nice new surface. I see what your saying but it might be worth getting it done now whilst it's off. I'll see what the machinest suggest for what figures I want. Quote Link to post Share on other sites
H_D Posted November 1, 2012 Share Posted November 1, 2012 go for 74.5mm as AdamB said as this will also eliminate the posibility of piston slap on cold start too Quote Link to post Share on other sites
Lew91 Posted November 1, 2012 Author Share Posted November 1, 2012 74.5 it is then, don't like the thought of piston slap. Quote Link to post Share on other sites
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