Black Top Woes.

[nzhogrider]

I bought a 1996 BZG 89,000 K's and luckily inherited the engine with a nice hole under the oil filter at the number 2 cylinder where the conrod has decided to make a hasty exit.
Any-one know of a blacktop bottom end for sale ? Done around the same K's ?
.........or anyone tell me what it would take to use a silvertop bottom end and mount the blacktop head etc on that ?
any help would be great......thanks

[EVL20V]

unlucky purchase bro

[Lloyd]

Where in NZ are you? If you're down south then I've got a silvertop block if you're interested. Pistons and things too, just run a bearing on number 1. Possibly missing a cap for that piston but I haven't had a look yet (bought the engine for the head)

[Mr Revhead]

theres a coupla issues with using a silvetop block, a couple of the hole setc dont line up, but its only minor details, sorry cant remember specifics.

if you can use silvertop rods, blacktop pistons.

[nzhogrider]

If you could possibly find out the specifics of the differences I would be absolutely stoked to hear about them.
My blacktop pistons are unfortunately not a complete set anymore, I found remnants of at least one of them lodged in the radiator, so I would need to get new pistons. What's the difference in the piston's ?

[Mr Revhead]

its very minor, so minor i say just do it!


the pistons alter the compression, blacktop is 11:1 silver 10.5:1


sound like this had been thrashed... similar failure to the rally car i worked on (not the engine!)

[nzhogrider]

OK Warwick, here's possibly a slightly more curly one.
The silvertop has squish bands in the combustion chamber, lowering the volume for the swept volume to be compressed into.
I take it the bore and stroke of the blacktop and silvertop are identical.
So if the Blacktop has an open hemispherical combustion chamber design, then the volume would be greater, therefore requiring a quite noticably larger dome on the piston to maintain the same compression ratio as the silvertop let alone increase it.
So a blacktop head on a silvertop bottom end would be lower on compression than standard silvertop.
But silvertop head on blacktop bottom end may be even higher than the blacktop's compression ....... if the piston dome dont hit the squish bands that is.
What's my best option ? I have a complete blacktop engine as fitted to the car that is poked, block holed, crank buggered, at least one conrod and piston buggered also.
And I have a silvertop longblock on the floor beside it, what's the best option of marrying this all up ?
Bear in mind that I also have the silvertop quads and extractors also, but no other engine ancillaries.

[Mr Revhead]

has any one cc'd the combustion chambers?
the difference between the 2 pistons isnt huge, but its definitly noticable...
plenty of ppl have put black heads on silver bottoms.
i havnt heard of any issues.... and i havnt had the chance to compare them side by side except in pics

if i was you id source another blacktop piston, and rebuild using:

silvertop block, crank and rods, for all the rest use the blacktop bits.
the weaskest link in the blacktops is as youv found, is the rods.

from what youv got that sounds like the cheapest and easiest option.
i did a price check on blacktops today..... they are not cheap!

[nzhogrider]

a price check on blacktop what ? pistons, or whole engines ?

[Mr Revhead]

2nd hand complete engine loom and ecu. over $1400 plus gst.......

[RedMist]

Mr Revhead told me to edit this post.

And me being the sheep I am.....

I told him to stick it so far up his lower intestine that it would take a week to pass.


Then...I edited the post.

[Mr Revhead]

good boy

[vvega]

i have 2 sets of blacktop pistions if thats of any help.....
id say put pistons in ya silvertop block put on blacktop head(it bolts striaght on) and just match and use your blacktop quads

then you have a blacktop with stronger rods....eazy as

hope that helps

v

[nzhogrider]

vvega how much for a set of those pistons ? I'm interested and genuine, let me know, ta.

Sean

[10k 20v]

hehe, i got me a complete blacktop for 900 inc gst, excluding loom and ecu, but it was an auto so loom and ecu useless ne how and i run a link+, so it is possible to find cheap ones

[Mr Revhead]

yes bargins are always there.....

did a ring around today, no joy on anything even close to a grand

[10k 20v]

also, as previously mentioned, for a strong engine use silver bottom including crank and rods, add some arp rod bolts, use trd bearings with blacktop pistons, then sandwhich every other blacktop part on top (throttle bodies, cams, etc, etc), also use the blacktop oil pump or you'll loose the silicone tensioner and you won't be able to use a blacktop cambelt, which will make it a tad more dificult for ordering parts later on and take away some of the blacktopiness

[vvega]

hehe, i got me a complete blacktop for 900 inc gst, excluding loom and ecu, but it was an auto so loom and ecu useless ne how and i run a link+, so it is possible to find cheap ones

haha that was a bit of a special deal
a nice trd head gasket wouldnt go amiss ethier


v

[Mr Revhead]

not on pump gas with a stock ecu you dont!

[nzhogrider]

bump