VN series 1 questions for rebuild

[needwork2-4fillhabbit]

My motor comes out this weekend i have ready to be fitted:
Heavy duty crow cam valve springs
ACL race series full gasket set
Genie extractors

Im having a late concern with the heads, im wondering if i should get a 40 thou oversize bore done to regain full compression.

Anyone know a rough price on a bore and hone?

And what is the standard bore size of a stock 3.8l?

[Tom_1569]

When boring, go minimal, going bigger then you need to only decreases the live span of the block. Unless your building a once off short term race motor theres no need to do large boring.

[needwork2-4fillhabbit]

Is 40 thou a big size? How much is the bigger bore sizes?

[needwork2-4fillhabbit]

And anyone know what sort of price to expect for rebore and hone? Also will the old rods fit the pistons?

[vn calais manual]

go 20thou, thats a nice size, standard rods should be fine. no idea on the pricing of the bore and hone, but the pistons and rings can be quite expensive.

[Bz Kn33z]

Is this for your supercharged engine??, if so acl head gaskets are crap, i have blown a brand new pair and i have also heard of another vp supercharged engine doing the same.

[Zuicider]

see if you have a lip at the top of your bores. pretty easy to hone it within spec yourself you just need the right honing pattern to help bed in the rings. u can buy buick turbo pistons from the US for a hell of a lot cheaper than shitty acl ones here.

[needwork2-4fillhabbit]

Already have pistons and rings... ACL ones.... Snap! Oh well if the gaskets blow ill get better ones. I can get the bore and hone done at a reconditioners for 200. So i guess ill see how the acl stuff holds up...

[Pub247]

if you already have pistons what size are they? you need to bore or hone to that size. As for going bigger decreases the life span is crap all going bigger means is its lees you can bore out again piston are usually only made up to 60 but you could resleeve if needed or bothered wasting the money.

[needwork2-4fillhabbit]

The pistons i have are 40 thou as i was warned when i bought it it might have a scratched bore. Lucky 40 thou will get it out. And the thing is i dont mind going 40 thou cos i have a complete motor out of my donor vp, wouldnt resleeve but id just regasket the other motor.

[Tom_1569]

if you already have pistons what size are they? you need to bore or hone to that size. As for going bigger decreases the life span is crap all going bigger means is its lees you can bore out again piston are usually only made up to 60 but you could resleeve if needed or bothered wasting the money.

Hey, not going to argue with what you wrote, caus I know you have alot more knowledge then me lol. But Im going to pick your brain.

I was taught that when boring you only go minimal because that way you can rebore again if you need to (increasing lifespan?), also the more you bore, the thinner the walls get, aswell closer to the water jackets and oil galleries, which can decrease the lifespan of the motor. Is this just a crock, or was the person speaking some sense?

[needwork2-4fillhabbit]

Same as i always did with motor bike bores, but the lifespan was cut short only cos i ran outta bores and had to resleeve ehehe. To many piston ring breakages.

[Tom_1569]

Oh for **** sake. I just recieved neg rep AGAIN for asking a ****ing question, this site has gone to ****ing shit.

[Pub247]

Tom i never left you any rep. When reboring it is best to go as minimum as possible. Sometimes i've seen virgin blocks that dont clean after being bored to 20 and you end up having to go next size up. What you say is correct but a well built motor thats been bored to 60 can last a few hundred thousand kays
gotta go more laterz

[immortality]

Tom i never left you any rep. When reboring it is best to go as minimum as possible. Sometimes i've seen virgin blocks that dont clean after being bored to 20 and you end up having to go next size up. What you say is correct but a well built motor thats been bored to 60 can last a few hundred thousand kays
gotta go more laterz

spot on, it also depends on the casting. some can go out to 60thou, others that have suffered from some "core shift" during the casting process my be to thin through the bore wall at 40thou. if the machine shop is worth there salt they would ultrasonically test the bore walls to check for thickness and make sure you don't suffer any problems later. personally, for the cost of another complete 2nd hand engine i wouldn't bother with sleeving

[needwork2-4fillhabbit]

Yep full motors are so cheap now not worth resleeving. Really not even worth boring either, but for peace of mind a bore and rings will get my compression back. Backyarders who used to rebore my motorbikes bore always stuffed it and did the bore a little sideways caused havok on rings..

[Tom_1569]

Tom i never left you any rep. When reboring it is best to go as minimum as possible. Sometimes i've seen virgin blocks that dont clean after being bored to 20 and you end up having to go next size up. What you say is correct but a well built motor thats been bored to 60 can last a few hundred thousand kays
gotta go more laterz

Hey mate, nah I know it wasnt you that left it neg rep, I can guess who it was though lol. Cheers for clearing that up to, much appreciated.

[needwork2-4fillhabbit]

Hehe i gave you 1+ to fix it up, you seem to offer alot on the forum.