Need help from engine builders

[DanTurboLancer]

Hey guys, this isnt actually for me,
My best mate has just had to rebuild his Ford 4WD engine,
its a B6,
Now is the same as our 4G54 motor?
because he is saying his has 2 balance shafts??

Anyway his fatherInlaw helped him with the rebuild, and his father in law is a motor mechanic by trade,
and a pretty good one too.

Anyway they have put the motor back together,
starts no worries, idles fine.
Bring it upto 2000RPM and it starts rattling its head off through to 3000 rpm then goes away.

They thought it may be the Hydraulic lifters locked up.
But they pulled them out and put them in a vice to check if they were locked or free, and they seem ok.

They put in elimination kits



Any advise on things to look for?
Reasons why it may rattle between 2,000-3,000 only??

Cheers Dan

[GB_BB4C]

Mine was doing the same thing, between 2000 and 3000rpm, figured it was just rubbing on something under the bonnet as it was jamed into a GB with EFI. Ended up with 15,000km put on it since the rebuild, something went wrong in the bottom end, really bad knocking noise. Havn't pulled it apart to see what happened though.That's about as much help as i can be though.

[oldn64]

Grab mechanics stethiscope (read big ass screwdriver) and find where the issue lies. Make sure the oil pressure switch is working and thatthe light on the dash illuminates when in ing position BEFORE starting it. If not make sure it has oil pressure before continueing. I had a mate say the same except his didnt rattle at frist and only lived 3 minutes then bang. he forgot the oil light and pressure test before doing anything else. Ran on no oil. I am not rebuilding a mess.

Next thing is if from the front make sure the tensioner has been done correctly...

Hang on a B6 is a DOHC 1600 that was in the lasers (KC-KE TX3's, capri's and early MX5's) Are you sure it is not a B2600/Ford courier? in which case it will be a either a G6 or a G54B? If the G6 this is does not share our motor, it is a Mazda motor whereas the G54B is ours....

Cheers

[SE Wagon]

They should also consider the phasing of the balance shafts. When I bought my Sigma it had a really bad vibe above 5000 rpm (so much that I never took it to redline), but all that went away when I replaced the timing chains and made sure I got the balance shafts right (first attempt, I had one out by one tooth - fortunately, something made me pull it apart to check it before I moved on).

Obviously, not the same symptoms. But who knows what could happen if both balance shafts are out of sync?

[wheelnut]

the b6 engine is a mazda engine not 4g54, they hav lifter problems always replace them there pretty cheap if u get aftermarket ones, they have oil pump problems also and if it has been overheated the pistons are known to "grow" and they knock or rattle depending on how big they get. find out if the bores had scuffs in them and if they did and it got hot or was knocking b4 rebuild measure the pistons it only takes a couple of thou 4 them to do it.the b6 also has balance shafts and the timing marks are very hard to see expeacially the the lower 1 as it is only a punch mark an the block.

[DanTurboLancer]

Ah yes my bad,
you are right the B6 is the Mazda/Laser motor.

I will assume it will be the G6, as it had 2 balance shafts so cant be the G54B same as our 4G54??

He is pretty sure [read as "Thinks"] its a G6 ;)

Cant be balance shaft issues, they fitted 2 balance shaft elinination kits.

They are scratching their heads at this stage.
They are thinking they may have shaved the head too much and the valves hitting pistons...
I would assume the noise would be continuous not just between 2-3 thousand,
and it would damage the valves causing it to loose compression and stall out?

[oldn64]

Ah yes my bad,
you are right the B6 is the Mazda/Laser motor.

No issue Dan just clarifying... I suspected that the motor size might have been a little small... ;)

I will assume it will be the G6, as it had 2 balance shafts so cant be the G54B same as our 4G54??

There were two motors used with these vehicles the earlier ones got the G54B which is a mitsu motor and did run shafts but also was 2555cc in capacity. the later ones had the G6 being a mazda motor and had capacity of 2605cc These motor have nothing in common to our motors, but I am not sure whether the bellhousing pattern is the same or not. I believe that these changed around the 1990ish period.

He is pretty sure [read as "Thinks"] its a G6 ;)

Cant be balance shaft issues, they fitted 2 balance shaft elinination kits.

So having cleared that up what elimination kit did they use.... Mazda or Mitsu? this might be a key

They are scratching their heads at this stage.
They are thinking they may have shaved the head too much and the valves hitting pistons...

Did they plasticine the motor to find out clearances or just throw it together?
Do they have any idea of how much CC the chambers are?
The other thing is with the head being shaved did the tensioner come up correctly. I suspect I would be tearing the thing down again and checking things out. For the price of the gasket kit it would be worthwhile.

I would assume the noise would be continuous not just between 2-3 thousand,
and it would damage the valves causing it to loose compression and stall out?

Depends on clearances. how long has it been running? could the carbon layer that has been placed on the top of the pistons be hitting valves now?
Was the cam degreed?
Is there a higher lift cam in it or a standard?
if you rotate the motor by hand does it grab?
what does a compression check result in?

Number of things in the unknown.....


Cheers

[A112H]

Sounds like timing chain slap to me, check the tensioner