Engine rebuild recomendations + gaskets?

[jaffaz32]

So i'm going to plan on doing a SOS stage 2 engine rebuild on a C30A.

I would like to be able to run the 550 wheel quoted on their site, might not run as much as that, will probably go between 500-550.

https://www.scienceofspeed.com/index.php/nsx/enpp/engine-services/fi-custom-engine-program.html

Do i need to replace every factory gasket in the block/heads?

If so does someone have a list of part numbers?

I have lots of gaskets already, i need to cross reference what i need additionally.

There used to be part numbers for complete gasket kits but they have been discontinued. I wouldn't need some like head gaskets / VVIS mainly.

I'm going to get the parts and supply to the machine shop/builder.

The stage 2 kit SOS offer options.

• upgraded connecting rods, recommended for applications >650 hp
• billet steel main caps, recommended for applications >650 hp (main journal align bore required)
• main stud kit, recommended for applications >650 hp (main journal align bore required)
• 36mm intake valve (for 3.0L cylinder heads)
• Darton Modular Integrated Deck (MID) sleeve

Would you do any of the above?

What about SOS Valves? do they go straight in or need machining? from the site i think you only machine the seats?
Valve springs/retainers? would you replace these with the SOS ones?

I actually already have brand new SOS 90.5mm 9.2:1 pistons and matching MLS gaskets but thinking if it's coming out, might as well sleeve it to have a stronger block and little more scope for more boost, would you agree with this logic as this involves selling my current pistons/gaskets as i believe the sleeves require 93mm as a minimum.

Any advice or opinions would be greatly appreciated, again i'm ordering the parts ahead of taking it to the machine shop. I need to do it on a relatively conservative budget as i did not plan to do a rebuild.

Thanks,

Chris.

 

[Mac Attack]

The aftermarket connecting rods, main caps, and sleeves are big-ticket items and will cost you a lot more for their cost as well as machining costs.

Valves, cams, cam gears, etc are all nice, but $$$. It all depends on your how much you want to spend!


At the minimum, I would:
* Timesert your engine block and use ARP head studs
* Buy a newer OEM crank dampener or go with the ATI
* Use the new Honda LMAs
* Replace your OEM oil cooler and flush our your SOS cooler if there is a hint of metal particles in your engine (per your other thread)
* Keep your SOS pistons and matching HGs (I have sleeves with 90.5mm pistons)

Everything else IMO depends on how much you want to spend.

I thought the SOS system was to ship your engine and they do all the work? Why are you taking it to a machinist then?

If you are on a conservative budget, I would not do any of the bulleted items in your list... except maybe the sleeves depending how bad your OEM ones are. If you do the sleeves, I highly recommend Dan Benson in the USA.

Sorry to hear about the engine problems....

Dave

 

[jaffaz32]

Thanks again Dave.

What does Timesert mean?

I already have the ARP head studs (brand new), ATI crank (used on the damaged motor), SOS LMA's brand new in packet.

I will purchase a new factory oil cooler as recommended.

Interesting, what sleeves did you use? I was under the impression when you sleeve you had to go 93mm but when i double checked that's for the Darton's

I spoke to my engine builder, he said he can sleeve the block in the price he quoted as he allowed for it, but if i went Darton it would cost allot more. Are AEBS good sleeves? Allot of good reviews. Do they require allot of work to install like Darton's or allot easier like other branded sleeves?

Very good point, i will not consider my bullet pointed options except valves, well i will have stock cams. I can stretch to the SOS valves assuming they don't require anything additionally and maybe even the springs, retainers they offer but not sure of the benefits of installing these?. I think i'm correct in thinking that the C30A motor is more restrictive and the valves will allow it to breathe better.

My engine shop actually said for a boosted car 90.5mm is better than 93mm because there is more metal around them making the block stronger. So that's good I don't need to swap the pistons.


In terms of oem gaskets, is the general rule, replace everything..... both heads and the block? Is there a list of every gasket in the engine and heads?

you are right, the SOS package is to ship your engine to them, i was going to purchase the parts i need to get it done locally. I'm not sure how to go about shipping my engine from UK to USA to UK. We have to pay import duties when items arrive here in the UK, not sure how i would go about explaining the engine is mine, i shipped it and shipping it back.


I have actually been offered an Comptech built 13.5:1 motor, the engine is here in the UK, it's not sleeved but has 90.5mm pistons which have only done dyno miles apparently. I have the option of swapping my 90.5mm pistons in to that block.

Would be interesting but might be more hassle than it's worth. It does have Comptech killer cams though, which i do know you get NA/FI cams so not sure how the comptech NA cams would work with a FI engine, if they would be of benefit or actually loose power. It is tempting though being Comptech built, even with the pistons swapped i know the heads will be in top shape built right, even the crank and bearings, oil ways should all be machined/cleaned right. Price wise it work out a little more expensive than building mine but means i could sell my oil pump, head studs, timing belt to help offset the extra cost.

The engine has changed hands a few times, which does leave a little doubt, has anything been lost in translation, spec wise etc.

 

[Mac Attack]

I would skip on the Comptech motor personally.

Every gasket/o-ring needs to be replaced in these engines except for the metal exhaust manifold gaskets and the phenolic intake manifold gaskets.... The remaining rubbers are expensive. You'll also need to buy separately a new crankshaft main seal (by the clutch), and (4) camshaft plugs (OEM work fine). I recommend new knock sensors on old engines (they are cheap but one of them is a pain to get to when it goes bad).

It's also good to buy new rubber hoses, thermostat, and TB/WP.


Dan Benson has sleeves made to his proprietary specs. If you do a search on here, there have been old discussions about the various sleeves, including the AEBS ones. The iron grade used for the aftermarket sleeves is typically much better than the grade OEMs used. I would feel comfortable running 93mm pistons with a good sleeve at your planned boost levels. Is the slight power gain by increased displacement worth it since you already have the 90.5 mm pistons?....

Timesert info can be found here:
http://www.nsxprime.com/forum/showthread.php/156458-Timeserts-for-Headstuds?
Basically, you drill out the old weak aluminum threads in the block and insert these larger carbon steel threads in place for the head bolts (or studs) to thread into. More than a few NSX engines have pulled out their aluminum threads unfortunately.

I still say stick with OEM valves. The performance gain / $ ratio isn't worth it, especially when considering the common aftermarket titanium retainers wear quickly and need to be inspected every so often (recommended every 10-15k miles). Not something I'd want to live with just to say I have titanium retainers.

If you are doing a rebuild and have passed metal through the engine, I would definitely replace the oil cooler (like you said), and carefully inspect the oil pump for signs of wear. What new oil pump do you have? A high-volume one with a new housing, or just the replacement gears?