Reply
 
Thread Tools Search this Thread
 
Old 27 October 2012, 11:20   #71
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
I am going to get No 5 liner pushed out to see if the block is deformed or cracked, as can't figure out why just one point on the bore has ovalled outwards by 5 thou? If the block looks ok, then will replace all the liners and measure up the pistons to see if they will go again. (not holding my breath). The pistons are not the same as tractor / truck. The bowl has to be machined to alter the compression ratio. The rings need to be chrome type to cope with the turbo.
The valves themselves may go again, it is the seats in the head that are not good.
__________________

__________________
Rokraider is offline   Reply With Quote
Old 29 October 2012, 13:06   #72
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
Block is scrap.... Cracked behind the point where the liner is deformed. Possibly caused when liner was installed?
__________________

__________________
Rokraider is offline   Reply With Quote
Old 29 October 2012, 13:18   #73
Member
 
Country: USA
Town: Seattle
Boat name: Water Dog
Make: Polaris
Length: 4m +
Engine: Yamaha 60hp
Join Date: Apr 2007
Posts: 1,152
Ugh
all this diagnostic effort and now what?
__________________
captnjack is offline   Reply With Quote
Old 29 October 2012, 13:54   #74
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
Another block has been sourced, will have it crack tested, light skim on the head face to ensure it is flat. line bore the main bearings and then fit new liners. As I am into it this far now, going to raise the compression ratio a bit, should help with smoke when cold. Have found some brand new, but old stock pistons that I will have the bores machined to.
Turns out the crank needs a grind, so will have that done as well. just the rods to check and hopefully it will start to go back together.
__________________
Rokraider is offline   Reply With Quote
Old 29 October 2012, 14:56   #75
Member
 
A1an's Avatar
 
Country: UK - Scotland
Town: Fort William
Make: Humber Destroyer
Length: 5m +
Engine: Yamaha F80
Join Date: Mar 2012
Posts: 2,239
RIBase
Blimey!


If you didn't have bad luck then you would have no luck at all!
__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
A1an is offline   Reply With Quote
Old 29 October 2012, 15:12   #76
Member
 
Country: USA
Town: Seattle
Boat name: Water Dog
Make: Polaris
Length: 4m +
Engine: Yamaha 60hp
Join Date: Apr 2007
Posts: 1,152
Is the Saber worth all this effort? Its not all that modern of a design (although my knowledge of it is 2nd hand)
__________________
captnjack is offline   Reply With Quote
Old 29 October 2012, 16:33   #77
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
This Rib was apparently a development boat built by Halmatic to evaluate using a Jet on a Pacific. It is interesting and quite different to the later production models. I wanted to restore it to its former glory with a couple of modern tweaks to make it more user friendly. I have a 3.0 BMW Tdi in bits that I could have assembled and marinised that would happily make 275 BHP all day long at probably half the weight, but I like the idea of a big old chugger working properly, so I continue on this quest. Apart from the financial horror it has become, I am actually really enjoying the project. It would be nice to get a couple of breaks though.
__________________
Rokraider is offline   Reply With Quote
Old 30 October 2012, 10:05   #78
Member
 
Country: UK - Wales
Town: Here
Boat name: doggypaddle
Make: Avon 5.4 Searider
Length: 5m +
Engine: yamaha 80
Join Date: Jul 2007
Posts: 1,107
Quote:
Originally Posted by Rokraider View Post
Another block has been sourced, will have it crack tested, light skim on the head face to ensure it is flat. line bore the main bearings and then fit new liners. As I am into it this far now, going to raise the compression ratio a bit, should help with smoke when cold. Have found some brand new, but old stock pistons that I will have the bores machined to.
Turns out the crank needs a grind, so will have that done as well. just the rods to check and hopefully it will start to go back together.
How are you going to raise the compression ratio?
The pistons should be virtually flush with the top of the block, The head is Flat so skimming that makes no difference, Gasket thickness makes a small change to the bump clearence, the only real significant change can be a piston change which i would be weary of, the CR needs to be fairly Low as its turbocharged.
If the CR is 16:1 static its nearer 30:1 at 1 bar boost. the head gasket could be a weak point.
__________________
I am usually not as green as i am cabbage looking.
doggypaddle is offline   Reply With Quote
Old 30 October 2012, 13:51   #79
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
The new pistons will need to have the bowls machined to reduce the compression ratio to make them suitable for a turbo. They will be machined less than the old ones with a target CR of around 14.7:1 instead of the original 13.7:1. this should help burn the diesel at idle and should still be safe at the top end.
__________________
Rokraider is offline   Reply With Quote
Old 30 October 2012, 15:08   #80
Member
 
Country: UK - Wales
Town: Here
Boat name: doggypaddle
Make: Avon 5.4 Searider
Length: 5m +
Engine: yamaha 80
Join Date: Jul 2007
Posts: 1,107
I take it the the pistons aren't coated then which is good
I thought the CR of these engines was around 17-1. I am surprised the thing will even start from cold without Ether at the figures you quoted I have seen production petrol engines running CRs higher than that (mazda 14-1 in the new engines same as the diesel derivative)
Skip it and wing a 24 valve Cummins 6BT in there
__________________

__________________
I am usually not as green as i am cabbage looking.
doggypaddle is offline   Reply With Quote
Reply

« Great Service | Top | scam? »
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 10:19.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.