The V8 Owners Forum -

I believe I may have sourced some cross bolt bearing caps for my interim 3.9.

Obviously they will need line boring but I am concerned that they may be so badly mismatched that they could not be corrected and thus have a similar problem with the mains as I have had with the conrods which I have recently posted.

He wants 400 quid for these!!!!!

Opinions please?

£400 for the caps?

+ line boring (dont have a clue who does it over here and I guess wont be cheap) + a hone, then oversize bearings etc.

Would you not be better off getting a good girdle fitted? That with ARP main studs should be good for as much power as a 3.9 RV8 could chuck out I'd have thought?

Yes, steep I know.

I deliberately sold my early 3.9 block so I could get the cross bolt one, unfortunately it didn't have the caps upon stripping it. And 400 quid is less than it would cost to have some caps made.

Hi
you should be OK in that there is far more meat on a main cap so you can take more off it before it gets to the point where you can't take anymore off. However £400 seems a bit steep to me for the caps, a nice bottom end brace on here a while back was about £250, (probably get two waterjet cut for that out of 1" ally plate for that and sell 1 on ebay) With a set of long bottom end studs comming in at about £100 you have £50 left for a decent curry and a few pints (maybe even take the wife/girlfriend/ significant other) just seems a better investment of £400 to me and would produce a stronger bottom end set up.
Best regards
Mike

Do make sure they are not for a 4.0 or 4.6 engine because they have larger bearings. and are not compatable with a 3.9 block.

£400 sounds a bit steep, where from JE or DJE try haggling.

Kevin.

kiwicar wrote:Hi
you should be OK in that there is far more meat on a main cap so you can take more off it before it gets to the point where you can't take anymore off.
Mike

Worried that if I have to take off so much then I would move the centreline to close to the cam. A few thou would be ok, but it might be a lot more if they are badly matched.

CastleMGBV8 wrote:Do make sure they are not for a 4.0 or 4.6 engine because they have larger bearings. and are not compatable with a 3.9 block.

£400 sounds a bit steep, where from JE or DJE try haggling.

Kevin.

The rv8engine parts shop on fleabay. Is that DJE?

Yes I have emailed him again to ask him about that to make 100% certain.

I might not bloody bother.

you arn't going to move the crank close enough to the cam by line boreing to make any differance to the slop of the timing chain after 2k miles, sorry but chain slop will dominate this one
Mike
PS I'd still go for the curry option.

What if the caps are like erm...1mm out or something. That would mean a huge chunk to take out the block wouldn't it?

And also what would I do with the registers?

Hi
1mm out where? they have to fit the same bearing shells, if they are that far out they would never fit the bolt holes. even with rover monkeys putting them together they could not be a 1mm differance block to block and be able to just pick a set of shells and a crank off the shelf and do up the bolts. . .

Mike

By the way at £400 for a set of shells I really do think they are having a humerous interlude
Mike

kiwicar wrote:Hi
1mm out where? they have to fit the same bearing shells, if they are that far out they would never fit the bolt holes. even with rover monkeys putting them together they could not be a 1mm differance block to block and be able to just pick a set of shells and a crank off the shelf and do up the bolts. . .

Mike

like the centres of the caps are say 1mm to the left or right of the centre line of the lock.

"like the centres of the caps are say 1mm to the left or right of the centre line of the lock."
I supose it could be, but i am pretty sure that it all has to register to the bolt holes in the bearing caps, after all they are made undersize, bolted onto the block and line bored in situe. You've still got to register to a referance on the block.
It could be 1mm out but that is one hell of alot, If they want £400 for them then I would insist it is on the basis that if they can't be machind to fit then you send them back.
Have you got a drawing of these caps, I have a shaper in the garage in three bits, you are rapidly motivating me to put it together and fire it up.
Best regards
Mike

I'd still go for the girdle option, when it is bolted to the block as well you will have the equivalent of either 4 or 6 bolt mains, half the price and it will stiffen up the bottom of the block more too.

ppyvabw wrote:

CastleMGBV8 wrote:Do make sure they are not for a 4.0 or 4.6 engine because they have larger bearings. and are not compatable with a 3.9 block.

£400 sounds a bit steep, where from JE or DJE try haggling.

Kevin.

The rv8engine parts shop on fleabay. Is that DJE?

Yes I have emailed him again to ask him about that to make 100% certain.

I might not bloody bother.

Yes that's Dave Ellis, DJE he appears to just sell parts on e-bay as I think he shut down the main business some time ago.


Another thought which may be feasable and cost effective is to look out for a 4.6 crank, a set of late mains caps which should be cheaper and have the block line bored for the larger crank bearing size, you then have the option of building a more interesting engine possibly with 4.0 rods and those Modular ford 260 pistons that Ian Stewart is using which were very good value.

Kevin.