4.6l 3V main bearing clearance

[ARMORINE]

ok i need help. im building a 3v eagle long rod stroker motor. my main bearing clearances are coming in at .0024-.0029 inch which according to the manual is far too loose. has any one else had this issue? this engines going to be used weekend warrior road racing(hallet) i was already planning on running heavier motor oil but am concerned this may not be enough with the clearances being so loose. i had the block machined by a local machine shop that has experience with mod motors.

 

[eighty6gt]

Crank is as furnished by eagle? May need to get it fitted to oversized bearings.

 

[ARMORINE]

cranks direct from eagle. only think i had done to it was sending it to microblue for coating

 

[hamish]

I'm running .0025" clearance.
using 15-40 right now, I have used 20-50.
Running good.

 

[ARMORINE]

I'm running .0025" clearance.
using 15-40 right now, I have used 20-50.
Running good.

whats your engine specs?

this engines completely n/a so its gonna see rpms as high as 7500.

 

[hamish]

Loosey goosey

.020" over
3.8" stroke
.0045" ptw clearance
.00225" rod clearance
.0025" main clearance
.018" side clearance



recommended 20w 50
currently running 15w40

It'll turn 7k easy, but no need.

 

[ARMORINE]

well eagle told me to call an engine builder...kinda annoyed by that...any one know a builder thats willing to help a DIY guy?

 

[eighty6gt]

Anecdotally the heavier oil will do it for the bearings, as outlined above (provided the oil pump is the same.)

Phasers, and the rest of the system, who knows. Will your rods have factory or larger clearances?

Were it me I'd run factory clearances, 5w20, and get some oversized bearings and have the crank made to suit.

 

[ARMORINE]

the phasers and the rest of the system are what im worried about. im going to be running a forged pump so im not worried about that...its just suck horribly if the phasers didnt work with the heavier oil.

 

[eighty6gt]

It's an unknown quantity. Since I want phasers, I use the oil they were tested with.

 

[ARMORINE]

Anecdotally the heavier oil will do it for the

Were it me I'd run factory clearances, 5w20, and get some oversized bearings and have the crank made to suit.

i agree with you on this. i ordered 1 thousands over bearings. gonna try to get all the clearances below .0019 but above .0015.

 

[1bad99]

i had issues with eagle sending me wrong bearings once i needed 25mm (.010) and they sent me 26mm mains. i failed to check clearances and had zero oil pressure pulled out swapped out mains and boom fixed

 

[ARMORINE]

i had issues with eagle sending me wrong bearings once i needed 25mm (.010) and they sent me 26mm mains. i failed to check clearances and had zero oil pressure pulled out swapped out mains and boom fixed

i feel ya. i finaly got the .026mm in. gonna fit them and check clearances saturday. so much to do to get this thing on the road. im so ready to be drving it again

 

[702GT]

the phasers and the rest of the system are what im worried about. im going to be running a forged pump so im not worried about that...its just suck horribly if the phasers didnt work with the heavier oil.

Just an observation, but if you plan to rev this motor to 7.5k/rpm why not lock the VCT out and degree the cams yourself, and save that oil pressure for more critical area's of the motor? It's not to say VCT won't work at high rpm, but it is a liability. The advantage of VCT comes from cam grinds with Advance cut into the cams. When VCT rests at 0*, the cams are actually advanced due to the grind. VCT retards the cams accordingly at partial and WOT. However, at WOT typically between 2-4k/rpm the VCT calls for 0* (giving the low-end opportunity) and right around 4k/rpm the VCT swings a few degrees (9-12 degrees retard, depending on the cam you run and where it's advantage is). Depending on gearing and what tranny you're running, shift points from 7.5k/rpm are going to net you roughly 5.5k/rpm as a bottom-out shift, every gear after that should be well above 5.5k/rpm. VCT will never need to adjust, however could become a liability due to the need for better springs and likely a higher lift cam, which have been known to cause VCT failures/malfunctions.

Just throwing it out there.