Pulled the DB4 Motor Today - Page 4

CJFusco · CJFusco's Garage

Love this thread. We need more rare care DIYers here in OT...

Hugh R · 01-19-2007, 04:35 PM

Ready to check the main bearing clearances with Plastigauge.

I got 0.00125" to 0.00150" on the main clearances, took a pic of each one for documentation. Will do the same with the rod bearings.

Used moly assembly lube and torgue to 85-90 ft.-lbs.

Slightly out of order, but wanted a pic of the crank before putting on the caps.

efhughes3 · efhughes3's Garage

Hugh:

What kind of oil will you use? There's been a lot of talk about the reduction of additives, and what the new oils can do for older engines. Apparently a lot of MG owners were specifically cited having problems with failures after rebuilds. It would seem that Redline Synthetics, and maybe a couple of others still brew to the old standards which offer better wear resistance.

I can send you an article that was on our local PCA forum if you want to PM me your e-mail.

Joeaksa · 01-19-2007, 05:00 PM

Quote:

Originally posted by CJFusco
Love this thread. We need more rare care DIYers here in OT...

Hugh,

You are bringing back memories here...

Joe

My project last year, another Brit 6 cylinder engine!

Hugh R · 01-19-2007, 05:09 PM

Ed

I've been reading the same thing. Apparently with flat cam lobes such as mine, its a problem. I've been told to go with a 15-40 diesel oil such as Valvoline or Mobil.

Stevepaa, yeah it whines somewhat, most notably in reverse.

Joe, nice Jag! is that your garage? Looks huge.

Joeaksa · 01-19-2007, 05:17 PM

Hugh,

Was very lucky for 2 years. My old boss had a building that he used only half of. The front was offices and back an old Taxi company, which was empty. It sat empty for over a year until I finally talked him into letting me rent it. $200 a month for 150 x 100 feet enclosed with full heat and lighting, air and so on. Put every one of my cars in there and started to work.

Unfortunately 15 months ago he retired and sold everything, so I had two months notice to move everything out. Really threw a wrench in my plans as that also meant that we lost our jobs.

Life can be a ***** at times but you move on. The Jag is the one on my signature line and purchased new by my Father in 1969. It will stay in the family. May have it running this weekend and driving again by next week.

Hugh R · 01-19-2007, 07:48 PM

Well, I'm not the genius that I don't appear to be (or something like that). After torquing everything down, I can't turn the crank at all. Loosened up all the mains and now it turns without disturbing the caps. I'll have to tighten them one at a time and recheck the clearances. With a 3 foot long crank and block and both 45+ years old and 1.25 to 1.50 thousandths of clearance something ain't right. I'll report back later.

Joeaksa · 01-19-2007, 07:50 PM

Better that you checked now than by using the starter motor. Good call and good luck. BTDT.

Did you replace the rear main seal? Is it the rope type? Could it be too tight?

lendaddy · 01-19-2007, 07:59 PM

Could be the thrust clearances. Another stupid question is is you remembered to remove asll the platigage. Hey I've been hittin' the wine again

Hugh R · 09:35 PM

Hey Joe:

Yeah, the asbestos rope and permatex stuff on the front and rear seals, what a mess. You just have to mix it up and jam it in there. Anyway, its the center No. 4 bearing that is binding. I thightened the front and rear and it turned 360 degrees and smooth did the same with the 2,6-3,5 combination and they're good. It binds on the center at 30 ft.-lbs of torque. Its not the thrust bearings they're way clear of the journal.

Lendaddy:

Yeah, I cleaned out the plastiquage.

In looking at it, its one of my tightest clearances, 0.001" Question, should I pull the crank and hone out the bearing , or progressively tighten and turn the crank, with the moly lube, I might be turning for a while. When I turn it over by hand, the moly lube wiping is smooth as looked at from the bottom of the journal. Wait a minute, let me take a pic. Here it is.

Hugh R · 01-19-2007, 10:04 PM

I think I'll try moving some bearings around. My No. 1 journal had 1.5 clearance while the No. 4 had 1.0 thousands. I'll see what that gets me. Same size bearings.

Joeaksa · 01-20-2007, 04:30 AM

Hugh,

Have you put a mic on the crank journals and bearings? Would pull the crank and mic it, then put the crank main caps on and torque them down and measure their sizes, at least on #4.

Something is not right here. Bearings do not need to be "honed" (unless one of them is not the correct size, you just plop them in) and should not be "adjusted" at all.

You do not want to overheat a main journal/bearing with this so hope you find the problem.

efhughes3 · efhughes3's Garage

I'd think that the tolerances of the bearings would be quite tight, and that unless they had a QC issue, swapping bearings from one journal to another shouldn't make a difference. As Joe mentioned, it's probably best to mic the crank, and verify that the one journal is oversize. The "good new" here is that if it is, it could probably be polished down to size?

john walker's workshop · 11:38 AM

hard chrome can make a .020 journal standard size again??

oops, guess i should have read the 2nd page!

Hugh R · 01-20-2007, 02:39 PM

I think I'm good! I swapped a couple of bearing shell halves that had slightly more clearance (1.5 versus 1.0 thou.) and torqued it up and can now turn the crankshaft. Next, I'll be stuffing pistons into cylinders.

Joeaksa · 01-20-2007, 08:29 PM

Not sure I feel comfortable with this but you know your engine better than any of us. Swapping bearing shells should not have made any difference...

Hugh R · 01-21-2007, 04:29 PM

British trash doesn't have the tolerances they used to have, especially with 45 year old dies, IMHO. All I know is that I have 1.25 to 1.50 thou. clearances and it turns freely, no grabbing, no loose spots, same pressure to turn it 360 degrees.

JCF · 01-22-2007, 02:33 AM

That really is lovely

Hugh R · 01-25-2007, 08:57 PM

Had some oil pump bushing (new) issues due to binding when I torqued it up. Something to do with three bushings in a plane honed them out some more and got it to spin freely.

The head is on, and now I've gotta torque it and attach the timing chains. Plus clean off some of the Permatex 2B that squeezed out. I might not get to the mechanical timing for a few days. I won't be stuffing it back in the car for a few weeks, as I gotta travel for business the next two weeks.

efhughes3 · efhughes3's Garage

Looking good there Hugh. I wish you were in my neighborhood, I could at least make sure the "assembly lube" in the green bottles was plentiful and cold.