300+ rebuild

[Freightrain]

It has started.

 

 

Will take time, not sure how fast it will happen.  I have legs made up to get it off the floor and I can drop the pan.  Local guy has std pan that he will trade for my ESI pan(that won't fit my chassis).

 

Found a couple loose exhaust rockers(like more then 1/8" lash)hope that isn't a cam failure!  Didn't make any bad noises while running and had 70# oil pressure.  Will investigate that further.

My 3/4" IR won't break the head bolts loose, but was using adapter for 1/2" socket.  Need to buy a good 3/4" socket and see if that improves the performance.

 

Should have some updates next week?

 

[70mackMB]

Welcome back Larry.    .....Hippy

[Geoff Weeks]

3/4" breaker bar and cheater pipe are my go-to for stuff like that. Cheap to replace if something lets go. I have a torque multiplier for going back together.

[mrsmackpaul]

If my memory is correct, which is doubtful I reckon the head bolts are 220 pound so thats pretty tight, yeah a breaker bar and pipe as Geoff suggests is probably needed

 

Paul

[Joey Mack]

Those head bolts are torqued to 205 lbft.  A 3/4" breaker bar with a 3/4" socket should do it. 220 lbft is the highest i would go, when going back together, but 205-210 is plenty. Do you have the torque pattern, and it is 3 rounds tol done..

[fjh]

5 hours ago, Freightrain said:

It has started.

 

 

Will take time, not sure how fast it will happen.  I have legs made up to get it off the floor and I can drop the pan.  Local guy has std pan that he will trade for my ESI pan(that won't fit my chassis).

 

Found a couple loose exhaust rockers(like more then 1/8" lash)hope that isn't a cam failure!  Didn't make any bad noises while running and had 70# oil pressure.  Will investigate that further.

My 3/4" IR won't break the head bolts loose, but was using adapter for 1/2" socket.  Need to buy a good 3/4" socket and see if that improves the performance.

 

Should have some updates next week?

 

Just run the over head and check not the hard! Loose means nothing unless you’re on the valve set marks! That space is there to make the engine brake function! 220 is bolt tourque that said as Joey mentioned top end with studs ! Esi Engine 53 quart pan!

[Freightrain]

No engine brake(dynatard) that I'm aware of.  I would assume, like a gas engine, that even at TDC there should only be max clearance(.020?).  Not +.150.  all the rest that I could check without rotating it, were pretty close to .020 sumthin.  Going by "feel".

It's coming apart, so I will make sure things are okay.  Could just be lack of maintenance.

[Freightrain]

1 hour ago, Joey Mack said:

Those head bolts are torqued to 205 lbft.  A 3/4" breaker bar with a 3/4" socket should do it. 220 lbft is the highest i would go, when going back together, but 205-210 is plenty. Do you have the torque pattern, and it is 3 rounds tol done..

Have to wait to get engine on legs, as it is just sitting on a few pieces of wood.  Any big bar will have it laying on its side, on the floor! 😨 

 

I remember the 673 was like 150#? when I replaced a few broke studs years back.  At least that is what I pulled it to because that was all my torque wrench would go.

[Joey Mack]

I cant post the picture of my book. So here ot is for head bolts on your tip turbine.

Lightly oil the bolt threads, amd washers and the top of the holes in the head. Not the block threads. 3 stages of torque is , 50-125-200 lbft. .  I wish i could post the torque pattern. I will try again.. 

[Joey Mack]

https://photos.app.goo.gl/SYoBuVFDPgd92ayM7

Try this link

[terry]

Looks like you have bolts and not studs and nuts for headbolts, be sure to chase all threads and bottom tap and blow out bolt holes.   Terry

[Freightrain]

Will do.  Not my first motor rodeo.  Been doing hot rod stuff for nearly 40 yrs.

[fjh]

13 hours ago, Freightrain said:

No engine brake(dynatard) that I'm aware of.  I would assume, like a gas engine, that even at TDC there should only be max clearance(.020?).  Not +.150.  all the rest that I could check without rotating it, were pretty close to .020 sumthin.  Going by "feel".

It's coming apart, so I will make sure things are okay.  Could just be lack of maintenance.

It likely has a dynatard cam just no head gear ! nope you need to to follow the firing order to set the valves! 

[Geoff Weeks]

20 minutes ago, fjh said:

It likely has a dynatard cam just no head gear ! nope you need to to follow the firing order to set the valves! 

Caught me out the 1st time I ran the overhead on a Mack. Couldn't figure out what I did wrong! Once learned never forgot.

[mechohaulic]

27 minutes ago, fjh said:

It likely has a dynatard cam just no head gear ! nope you need to to follow the firing order to set the valves! 

that was a major challenge back in the day for the "old school folk" who had the white soap stone to mark the rockers after adjustment  since more than one valve on opposing cyl could be adjusted same time. then this dynatard engine comes along.- WTF I just adjusted that cyl why all the slack on exhaust.  read the book !! what book; they weren't printed yet. 

[fjh]

10 minutes ago, Geoff Weeks said:

Caught me out the 1st time I ran the overhead on a Mack. Couldn't figure out what I did wrong! Once learned never forgot.

Joey has mentioned this Many times on here  ! Can't stress it enough! Many get caught on it! 

[Geoff Weeks]

15 minutes ago, fjh said:

Joey has mentioned this Many times on here  ! Can't stress it enough! Many get caught on it! 

Yeah, my "education" was decades ago, but I still remember that today.

[Freightrain]

I've run valves, so I understand the procedure.  On my hot rods, I always do one cyl at a time.  They have cheat sheets on how to do multiple cylinders at a time but I never do it that way.  Ever.  Even after getting grief for it.  "Oh, you're taking too long".  Whatever.

This having so much lash surprised me.  Why does it require so much for a "dynatard" cam?  What is special about it?  I'm just glad it isn't a cam lobe problem.

I did the valves on my 237 and the Jakes without issues.  I know Jakes are different but I followed the sequence and they work fine.

I want to transfer the Jakes over to this engine, if possible.

[mrsmackpaul]

Have a read through this thread, ut may help or maybe just confuse the Dynatard understanding 

 

Paul

 

[Freightrain]

Ok, it makes sense.  It uses an adjustable rocker cup to apply extra lift to open the valve instead of a Jake housing.  Normal setting it has lash, once pressure applies it pushes rocker further opening the valve.

 

Kinda ingenious actually.

[mowerman]

Well Larry I’m glad you decided to go through it that’s what I would’ve done I’m sure most of us … bob

[davehummell]

I used to have to work on 675's with the dynatard but I haven't touched one in almost 40 years so my memory of setting them up is a blank. That 300 will make the B into a hot rod compared to your 673 when I installed the 260 hp it was a noticeable improvement. I am very glad I spent the money for the jake that is on my present engine.

[Freightrain]

The 237 is a huge upgrade from the 673.  Can't wait to see it with new motor!

 

I found out last winter that my throttle was not quite wide open at WOT.  I adjusted the arm just a touch and WOW what a difference.  It really pulls the hills now.  It was good but that last little touch of fuel made a big difference in keeping speed with my trailer on steeper hills.  Always had to drop a gear, now I can almost not have to.  Can't imagine another 100hp?

[fjh]

2 hours ago, mrsmackpaul said:

Have a read through this thread, ut may help or maybe just confuse the Dynatard understanding 

 

Paul

 

Rockers and valve covers and push tubes to make it work! The Jake’s should work  from the other engine! As it works off cam lift! Dynatard is rather feeble! Jake is moderately better!