TR4/4A TR4A Assembly by a rookie (me!)

[Popeye]

I will mention the one that I haven't seen here, and I didn't see it mentioned in the books when I did my 4A motor many years ago. The connecting rods are oriented or offset to one side. When I put my motor back together best guess/memory was wrong on which way. It became very obvious when the spin the engine by hand (rods hit the block if oriented wrong way).

Looks like you may be past that point, but this is a much better thing to figure out sooner rather than later.

Thanks! I will check this when I set the timing.

 

[Popeye]

Got a few things done this weekend. I rebuilt the oil pump using rotating parts from a replacement pump with the original castings (the new pump housing looked terrible, a lot of grinding on the surface). I discovered I don’t like cork gaskets. And I installed the timing chain and gears and built a timing wheel out of plywood and printed pdf. (Timing still needs to be set.) I picked up my freshly machine head over lunch today, ready for pushrod tube install. I plan to use threaded rod and tapered nuts to do the swaging, plus a loctite sealer (forget the number), as I saw in a posting - either here or on a British site.

And the piston connecting rods seem to be installed correctly.

Thanks for all your support, advice, and feedback.

I’m having fun!

 

[DrEntropy]

I share your disdain for cork gaskets. But after a while you get used to dealing with 'em. Since RTV became available about the only thing the shellac or aviation goop gets used for is sealing freeze plugs.

Use the "stop pin" method of finding TDC, you can MacGyver a stop attached to one of your liner retaining studs.

Nice BIG dial indicator ya got there, too!

Glad to learn you're enjoying the experience.

 

[charlie74]

Cool, another rookie! My block just came back from the machinist and is (slowly) going back together…I’ll be following your progress with interest. Good luck!

 

[Popeye]

Got my timing set last night. Made a simple plywood block to keep everything in alignment, and allow for a piston stop. Indexing is not terribly difficult, but did require a bit of head scratching to figure out which way to turn and flip the bits, as well as maths. (Fundamentally: set the cam in the proper position, remove the cam gear, rotate crank to its proper position, then figure out how to assemble cam gear to line up holes.)

I started the process by “eyeballing” the pushrods as equal at TDC to get the timing in the ballpark. Then I indexed basis intake valve (not exhaust!) being maximum open at 110 degrees after TDC.

Once I indexed the cam, I removed all the measuring bits (dial indicator and base, timing wheel, plywood block), then put them back on again to re-check the results. I got the same results twice… either I did it right or repeated the same mistake!

Two degrees advance… should I get closer?

 

[Popeye]

Also: Should I replace the timing chain tensioner?

It seems like I should... but it is not available from TRF, possibly suggesting either a quality issue with new stock, or a part that has low sales volume. (Other suspects have it.)

 

[DrEntropy]

Also: Should I replace the timing chain tensioner?

Yes. Don't go through all the rest and not replace it. Rimmer lists it and the pin. Put the old one in place while you put the rest together and replace it when the new one shows up. Or order more from them and offset the shipping.

 

[ckeithjordan]

Similar to what you're doing:

cam degree

macysgarage.com

 

[Popeye]

Similar to what you're doing:

cam degree

macysgarage.com

That design inspired mine I copied that design - but was missing springs to ensure when the cam "closes" that the followers are doing the same. The primary purpose of the plate is keeping the pushrods in place and allowing (more) precise readings with a dial gauge. Regardless, I plan to confirm the indexing once the engine is fully assembled (i.e. the head in place, but at a point when I can still access everything). At that point there will not be any "side-to-side" motion of the pushrods. Hopefully it will be a "confirmation", not an "adjustment"...

 

[Popeye]

Something I notice in the pix, looks as if the block's mating surface to the head has some discoloration from having been covered with a plastic and possibly grease? Clean it with acetone or lacquer thinner on rags to remove ANY contaminants. Same with head's mating surface. Another thing is the front cover gasket areas; they look as if the block had not been well cleaned/prepped before the rest of the work was done. Can't be sure though, just from the images.

Following up on this: Cleaning with acetone, as well as brake cleaner, does not remove any discoloration. Given the surface is smooth; nothing is perceptible with a finger or fingernail, I'm thinking to leave it as-is.

Thoughts? Should I hit it with fine (~600 grit) emery paper (while holding a vacuum in place to catch dust)? Use a more aggressive cleaner?

 

[DrEntropy]

If you've used acetone as a cleaning agent, and no residual gasketing material is present you're good to go. No sense in chancing any abrasive stuff finding its way into things it shouldn't.

If the parts were to be "boiled" (bare block, liners out) before boiling and assembly, I use "Scotch-Brite" green pads on a small pneumatic angle grinder to polish those surfaces. No appreciable loss of material and a clean shiny mating surface.
Tuck that info away for the next time (never say never! ).

 

[Popeye]

Made some progress:

Installed the timing chain and oil pan gaskets with a thin layer of rtv and weighted the assembly on a glass table to cure.

Got the new chain tensioner installed with a new cotter pin.

Unfortunately the original bolts holding the gear to the cam started to stretch when tightening to the required 24-26 ft-lb… I assume the bolts have been replaced with an inferior grade. I replaced them with grade 8 bolts (missing the shoulder), and torqued properly. In doing so , I marked the gears, disassembled, inspected the threads in the cam, and rechecked the timing when all was assembled again. Same results as previously.

nstalling a new oil seal was a bit finicky; it seemed as though my cover was slightly deformed - the depression where the seal fits seems slightly oval. But some careful work pressing it in got it home.

My pulley hub is pitted on the oil seal surface. Should I replace with new or buy a speedi sleeve? $90 for new, $60 for the sleeve. I’m tempted to keep the original part and install a sleeve, given variable quality of new. Thoughts?

As a parent I work in fifteen minute intervals… I also went to the Factory Five open house with the girls - very neat operation.

 

[sp53]

Did the new bolts torque up better? I used the old bolts and tightened them up and then wondered will i get these bolts to torque to 25. I just stopped torqueing when I figured and hoped it was enough. Next time I think I will try new bolts.
steve

 

[Popeye]

Did the new bolts torque up better? I used the old bolts and tightened them up and then wondered will i get these bolts to torque to 25. I just stopped torqueing when I figured and hoped it was enough. Next time I think I will try new bolts.
steve

Yes. The "original" bolts kept twisting at a constant torque around 25 ft-lbs. I figured if I kept it up, they would simply snap - and I stopped. (I was also concerned it could be the threads inside the cam... worrisome. Fortunately the threads in the cam looked great, and I was able to run a thread chaser (not tap) in and out with my fingers. Replacing the bolts with grade 8 seems to have done the trick.

Note - I am (for the most part) using grade 8 bolts. When I bought my assorted mix of fastener hardware, I did not want to buy two sets (one Gr 8 and one 5), so I spent the extra $ and have all zinc yellow-chromate plated hardware.

 

[charlie74]

Hi Popeye, a (quite likely silly) question regarding cam timing; how much does installation of the timing cover with the tensioner affect the internal timing? I’m guessing that the tensioner will advance the timing slightly over what you were able to measure with your degree wheel etc (?).
best regards and following with interest,
c74

 

[Popeye]

Hi Popeye, a (quite likely silly) question regarding cam timing; how much does installation of the timing cover with the tensioner affect the internal timing? I’m guessing that the tensioner will advance the timing slightly over what you were able to measure with your degree wheel etc (?).
best regards and following with interest,
c74

Interesting question. Not having the parts in front of me, but assuming: 10" distance between the center of the two gears, and the cam gear is 5" in diameter.

The maximum allowable chain deflection is 0.4" (new chain considerably less - I did not measure as it was clearly less than 0.4"). So a 0.4" deflection on a 10" run equals an extra 0.032" inches of distance. (Assume two right triangles, base length = 5", height = 0.4", then the hypotenuse equals 0.016" = root of the sum of the squares... times two = 0.032.)

The pinion gear circumference = pi*D = 3.14*5 = 15.71"

0.032 / 15.71 = 0.2%. 0.2% of 360 degrees is 0.73 degrees additional advance. Not a small amount. If the distance between centers is 8", and the cam gear is 4" in diameter this increases to 1.14 degrees. If the deflection decreases to 0.2", with 10" and 5" dimensions, the advance is only 0.18 degrees.

Hmmm...

I will re-check timing once the head is on - my intent was double-checking my work, but your question gives me an additional reason!

 

[charlie74]

It would have taken me a week to come up with all that! Thanks, I look forward to your follow up.
cheers!

 

[Stevenry]

I wouldn’t think the tensioner would effect timing because you pull the chain tight between the sprocket on the crank and the cam sprocket on the opposite side, as I recall. There is some variance, probably a quarter tooth’s worth whatever degree(s) that is, between the 4 possible positions to line up the cam sprocket bolt holes with the cam while the chain is tight.

And of course, the 4th one you try will be the one that is the best fit.

Steve

 

[DrEntropy]

I wouldn’t think the tensioner would effect timing because you pull the chain tight between the sprocket on the crank and the cam sprocket on the opposite side, as I recall. There is some variance, probably a quarter tooth’s worth whatever degree(s) that is, between the 4 possible positions to line up the cam sprocket bolt holes with the cam while the chain is tight.

And of course, the 4th one you try will be the one that is the best fit.

Steve

Spot-on, Steve! Thank you! As I was typing about the four possible positions and a quarter-tooth variance, got a visit from a friend and interrupted.

 

[Popeye]

Some more progress:

Installed the proper "cheesehead" screws in the front sealing block. Had to order these from Grainger.

Installed the oil pump (including gasket). I had to "borrow" a stud from the fuel pump, as one of the oil pump studs was stripped and I did not have a replacement handy.

Also installed the oil pan, but still need to figure out where the long bolts go - as can be seen in the photo both are incorrect! (None of the bolts are torqued at this point - no blue marks.) After some late-night research, it seems one long bolt goes where the clutch slave cylinder reinforcing rod mounts, but not sure the other. Note: Most folks say to put the short bolt in the aluminum block at the front. However I found the blind threaded hole by the dipstick to have shortest engagement depth and put it there. [update: see edit below] (At the end of the day it probably is not too important... all bolts have sufficient thread engagement to hold the pan.)

To prevent rust, I coated the inside of the oil pan with oil. (I did not use assembly lube given the large area - and not a friction surface.) Before mounting the pan, I cleaned the machined surface of the block with brake cleaner, and put a light coat of gasket shellac on the paper gasket. (Previously put a thin coat of RTV between pan and gasket. Tenacious stuff that RTV... None remains internal to the engine, but you can see a few flecks of it in the photos!)

As an aside, in the middle photo, you can see the "Lang" thread chasers I bought on Amazon. Love them - good use of $40!
(https://www.amazon.com/gp/product/B00DTEFSWY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)