Girdle for non-X Bolted block; namely 500
Discussion
Okay, so save the obvious 'girdle jokes', has anybody used one? Do they produce these for the RV8 to strengthen the bottom end as I'm aware the produce them for the Chevy with single mains bolts?
As a large proportion of the 500 blocks seem not to be X-bolted and I wondered if this girdle was a quick fix for adding additional rigidity to the bottom end; or; whether under a certain BHP this extra rigidity was even needed? This area is so confusing, some say you need X-bolted blocks, others say it isn't an issue and some say if it isn't broke don't fix it. As the 500 does't really rev past 6-6.5k is x-bolting really necessary and if so, would a girdle be a good alternative to replacing the entire block? Assuming the stroke is slightly longer in the 500, would this also mean that the con rod was longer and perhaps a combination of the two result in less sideways pressure on the stroke, reducing the need for x-bolting? This girdle looks like a good way of strengthening the block, but would obviously make the sump sit slightly lower too.
Having seen the snapped crank thing flying around on PH, it's difficult to decipher forum paranoia from engineering facts!!! Why did TVR X-bolt some blocks and not others?
Here's a few picks I've found. Two different girdles. The latter has the oil pick-up aperture machined in:
A
B
As a large proportion of the 500 blocks seem not to be X-bolted and I wondered if this girdle was a quick fix for adding additional rigidity to the bottom end; or; whether under a certain BHP this extra rigidity was even needed? This area is so confusing, some say you need X-bolted blocks, others say it isn't an issue and some say if it isn't broke don't fix it. As the 500 does't really rev past 6-6.5k is x-bolting really necessary and if so, would a girdle be a good alternative to replacing the entire block? Assuming the stroke is slightly longer in the 500, would this also mean that the con rod was longer and perhaps a combination of the two result in less sideways pressure on the stroke, reducing the need for x-bolting? This girdle looks like a good way of strengthening the block, but would obviously make the sump sit slightly lower too.
Having seen the snapped crank thing flying around on PH, it's difficult to decipher forum paranoia from engineering facts!!! Why did TVR X-bolt some blocks and not others?
Here's a few picks I've found. Two different girdles. The latter has the oil pick-up aperture machined in:
A
B
Good question, the 500 con rods are actually shorter than the others because the stroke is longer and the block is the same hight so they have to be. So con rod angularity is actually worse on the 500. ( not sure if the gudgeon pin sits higher in the piston to keep the rods as long as pos. but I believe they are still shorter) I am interested in reading the responses to this as I have pondered removing my non cross-bolted 500 and having it set up in a mill and drilled. It appears to bee possible but not sure if necessary (when producing less than 300hp) the girdle could be a simpler solution although as you say loosing 1/2" of sump to ground clearance wouldn't be desirable. Maybe you could shorten the pickup and sump but ad to the sides to maintain volume?
NZ fan said:
Good question, the 500 con rods are actually shorter than the others because the stroke is longer and the block is the same hight so they have to be. So con rod angularity is actually worse on the 500. ( not sure if the gudgeon pin sits higher in the piston to keep the rods as long as pos. but I believe they are still shorter) I am interested in reading the responses to this as I have pondered removing my non cross-bolted 500 and having it set up in a mill and drilled. It appears to bee possible but not sure if necessary (when producing less than 300hp) the girdle could be a simpler solution although as you say loosing 1/2" of sump to ground clearance wouldn't be desirable. Maybe you could shorten the pickup and sump but ad to the sides to maintain volume?
This is interesting. I've been in touch with the previous owner of my Chim and he seems to recall the last RR in excess of 300BHP and I've done a few induction mods and decanted since then. I have also purchased (although not received yet) a MS3 ECU, so intend to install wasted spark ignition and remove the 5AM AFM. So before increasing the power, I was considering strengthening the block to accommodate the potential extra horses.Apparently, the 500 blocks with the bosses for the X-bolts cannot be X-bolted as they do not have the correct bearing caps. A girdle would seem to be a logical way to avoid machining or replacing the block entirely. I am also interested in getting to the bottom of whether the X-bolting is truly necessary and if so, above what sort of BHP… and whether the girdle is available and a good alternative.
The idea of widening the sump is interesting, although, likely to get expensive.
Edited by Chuffmeister on Saturday 21st December 21:46
I have discussed this with another forum member previously who is more knowledgeable on the the RV8 that I am and one problem that arises is it lowers the already low sump nearer the Tarmac 
and yes it would be of benefit since the RV8 is not the most rigid block in the crankcase area 
up the HP & up goes the flexing (however small) 
RPM is the stinger IMO
and yes it would be of benefit since the RV8 is not the most rigid block in the crankcase area up the HP & up goes the flexing (however small) RPM is the stinger IMO SILICONEKID346HP said:
Mine is cross bolted , Nick with the Orange supercharged 350hp 4l does not have a cross bolted engine ,to date he has had no problems .
Can we call it the 24 hour Girldle
Dunno Daz… why 24 hour? I must be missing something?Can we call it the 24 hour Girldle
I sense this thread plunging into the Finbar Saunders' abyss… Nick's was a pre-serp wasn't it? So as far as I'm aware they weren't cross bolted. So why weren't they and on what empirical evidence was the X-bolting based?
The 500 engine is as i understand it a weak design.
The main issue, snapped cranks are because of a relatively weak design and poor quality.
Some have snapped at speed and others like Chimjunkies apparently on start up.
The later large journal 4.6s are of better design and are cross bolted.
The fact that some 5.0s aren't crossbolted doesn't make them weaker as far as the crank is concerned, it just stabilises the bottom end.
I'm sure someone like Rob will give the whole story but as far as a girdle on these engines is concerned, fitting one isn't the answer IMHO.
The main issue, snapped cranks are because of a relatively weak design and poor quality.
Some have snapped at speed and others like Chimjunkies apparently on start up.
The later large journal 4.6s are of better design and are cross bolted.
The fact that some 5.0s aren't crossbolted doesn't make them weaker as far as the crank is concerned, it just stabilises the bottom end.
I'm sure someone like Rob will give the whole story but as far as a girdle on these engines is concerned, fitting one isn't the answer IMHO.
Sardonicus said:
I have discussed this with another forum member previously who is more knowledgeable on the the RV8 that I am and one problem that arises is it lowers the already low sump nearer the Tarmac and yes it would be of benefit since the RV8 is not the most rigid block in the crankcase area up the HP & up goes the flexing (however small) RPM is the stinger IMO
Somebody more knowledgeable? Would it not be possible to slightly shorten the sump and perhaps raise the height of the internal baffle plate? and yes it would be of benefit since the RV8 is not the most rigid block in the crankcase area up the HP & up goes the flexing (however small) RPM is the stinger IMO Chuffmeister said:
Dunno Daz… why 24 hour? I must be missing something? I sense this thread plunging into the Finbar Saunders' abyss…
Nick's was a pre-serp wasn't it? So as far as I'm aware they weren't cross bolted. So why weren't they and on what empirical evidence was the X-bolting based?
Yes he probably just chanced it so to date it`s ok . I sense this thread plunging into the Finbar Saunders' abyss… Nick's was a pre-serp wasn't it? So as far as I'm aware they weren't cross bolted. So why weren't they and on what empirical evidence was the X-bolting based?
18 hour Girdle
http://www.youtube.com/watch?v=NUjmQlt_6mM
phazed said:
The 500 engine is as i understand it a weak design.
The main issue, snapped cranks are because of a relatively weak design and poor quality.
Some have snapped at speed and others like Chimjunkies apparently on start up.
The later large journal 4.6s are of better design and are cross bolted.
The fact that some 5.0s aren't crossbolted doesn't make them weaker as far as the crank is concerned, it just stabilises the bottom end.
I'm sure someone like Rob will give the whole story but as far as a girdle on these engines is concerned, fitting one isn't the answer IMHO.
Thanks Peter. It was after we spoke when I started to look into this. I was considering getting the crank balanced like you mentioned, but then as you have the engine in bits at this point, wondered whether it was worth getting the block X-bolted. Since that point, I've discovered that this isn't possible. It now starts to get expensive.The main issue, snapped cranks are because of a relatively weak design and poor quality.
Some have snapped at speed and others like Chimjunkies apparently on start up.
The later large journal 4.6s are of better design and are cross bolted.
The fact that some 5.0s aren't crossbolted doesn't make them weaker as far as the crank is concerned, it just stabilises the bottom end.
I'm sure someone like Rob will give the whole story but as far as a girdle on these engines is concerned, fitting one isn't the answer IMHO.
Also, if the crank is out and it is balanced, I am I assuming correctly that it will need new bearings and would the correct tolerances be machined and matched correctly to the crank?
SILICONEKID346HP said:
Yes he probably just chanced it so to date it`s ok .
18 hour Girdle
http://www.youtube.com/watch?v=NUjmQlt_6mM
So you can still fit into your wedding dress???18 hour Girdle
http://www.youtube.com/watch?v=NUjmQlt_6mM
Chuffmeister said:
Somebody more knowledgeable? Would it not be possible to slightly shorten the sump and perhaps raise the height of the internal baffle plate?
True 
but your average owner is a bolt on merchant and just how many are they likely to shift once they have done all that design CNC work etc? it wont add HP and you cant see it so it has a limited market IMO only the hardcore know the benefits tying things together and keeping things as square as possible 
hence you could sell to them 
Edited by Sardonicus on Saturday 21st December 22:30
If you sent the short block to Chessman Engineering, they would internally balance the whole assembly, normally cross bolting and line boring the block to ensure there are no stresses on the crank.
They would also fit new shells all round and probably recommend a hone.
This is assuming that there is no wear on bores, crank, small ends etc.
All this isn't cheap and at this stage it may be worth considering alternative engines.
Or, just leave it!
They would also fit new shells all round and probably recommend a hone.
This is assuming that there is no wear on bores, crank, small ends etc.
All this isn't cheap and at this stage it may be worth considering alternative engines.
Or, just leave it!
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