Engine Assembly Questions

[JPSmit]

You can't even begin to imagine how nervous I am about reassembling this engine - so, with your indulgance I will have lots of questions before I start. Here is the first round.

1. Do you reuse circlips? If not, can I get them at a auto supply store or are they mysterious British?

2. I laid out the studs for the head last night. 6 are 4 /16 inches, 2 are 4 5/8 inches. why are 2 longer & where do they go?

3. When inserting head studs, long thread up or down? and do I use loc tite or anything?

4. Bentley (p 209) talks about reinstalling pistons.
a) Which side of the cylinder is the "thrust side"

b) He advocated oiling the rings but elseware speaks of assembly lube. Can I use assembly lube on everything?

c) Which way are piston connecting rods aligned?

5. Do I need a special tool for installing piston rings on the pistons?

6. Tell me about reamers.

Thanks again y'all - I would be in serious trouble without this board!

 

[jlaird]

1. Do you reuse circlips? If not, can I get them at a auto supply store or are they mysterious British? Sure, can reuse em.

2. I laid out the studs for the head last night. 6 are 4 /16 inches, 2 are 4 5/8 inches. why are 2 longer & where do they go? The longer ones hold the valve cover on.

3. When inserting head studs, long thread up or down? and do I use loc tite or anything? No lock tight. Think threads are different on each end.

4. Bentley (p 209) talks about reinstalling pistons.
a) Which side of the cylinder is the "thrust side" Pistons should be stamped front I think.

b) He advocated oiling the rings but elseware speaks of assembly lube. Can I use assembly lube on everything? Assembly lube works great, be generous with it.

c) Which way are piston connecting rods aligned? Will only go on crank one way.

5. Do I need a special tool for installing piston rings on the pistons? No, but you need strong fingers and thrmbs.

6. Tell me about reamers. Reamer for what. Have machine work done at a machine shop and get it right.

 

[Bruce_B]

JP,
Best luck with the engine. I'm going to be assembling my 1275 next month so the questions and the answers you'll be getting are great.

Thanks in advance to all who answer these questions. I'm sure JP and I aren't the only ones needing this info.

 

[Glen_B]

Couple of things, As JL pointed out, the two longer studs hold on the valve cover, so put them in the front and back holes on the side away from the spark plugs. The coarse threads go in the block, fine to the head nuts. DO NOT overtighten them or they will slightly pull up the metal of the block and prevent getting a good seal with the head. In fact, the holes should be checked to be absolutely sure that the edges of the holes do not stand proud of the block surface. Most pistons can go either way, but use the numbers stamped into the crown to get them all the same. The rods have noticeably offset bigends and can only be fitted one way to the crank. If you look down the bores at the fitted crank, you will see how it must be. Use an assembly lube with molybdenum. Ring tools are relatively cheap compared to getting a set of replacement rings.
Check the rotation of the crank after torquing the mains, as aftermarket thrust washers are oversize bits of poop. Finding out later is a pain.

Glen

 

[Glen_B]

Oops, forgot.
You can rent a ridge reamer for the bores if your finger detects the slightest ridge. Its easy to do. Then be sure to rent or buy a ball hone to break the glaze on the cylinder walls so your new rings will seat properly. Its real easy to break a ring fitting pistons with a ring compressor. DO NOT force the pistons in. Well lubed, they should go in without ANY hammering. Firm pressure. I've actually switched to doing them by hand but the explanation is a long one.

Glen

 

[racingenglishcars]

Pistons have a thrust side. This is the right side of the engine. The wrist pin (gudgeon pin) is offset very slightly toward the thrust side of the piston. This may be so slightly offset that it is undetectable to the eye, but measuring will show it.

 

[Morris]

Hey Jp,

On your engine, the long studs do not hold down the valve cover. In honesty I do not know why they are longer or where they go. This may be a question for the Triumph Forum. But, all of the studs are the same length on the ARP set I just got, so I can't imagine that the placement of the long ones matters much. The short threads go into the block. Use a tap or thread chaser to clean the holes. They are 3/8-24 I believe. Then lube the threads with moly grease or 30wt motor oil. Double nut the top of the stud so you have something to grab onto, but only tighten the stud down hand tight. You can use lock tite, but only if you put the studs in right before installing the head. I would avoid it.

The thrust side of the pison is usually marked with an arrow. When installed, the arrow should be pointing to the camshaft.

Use assembly lube on all your bearings, camshaft and lifters. If you install the distributor drive gear last, you can use a cordless drill with a long flat screwdriver bit to run your oil pump (counter clockwise) to get oil into all of your bearings and passages before starting. Use engine oil for the rings. You can use a ring spreader to make installing the rings a bit easier.

The rod alignment will be self evident when you get in there. The heads of the bolts will face the camshaft side of the engine (if I remember correctly). Anyway, if you put them in the wrong way, it's nearly impossible to get to them with your torque wrench.

 

[Darwin]

JP,

The longer studs are used to hold the engine lift plate. I believe they are the back to studs on the carb side of the head. https://www.victoriabritish.com/icatalog/sm/0054.asp

They would be #41 on this link page.

 

[JPSmit]

OK, I'm still working up the nerve to start. All the parts are laid out nicely. One part I have a question about however is VB #1-371 Thrust washer set. I actually ordered both sizes as they were cheap enough not to want to reorder. What are they and where do they go - the diagram in the book doesn't seem to help as I can't figure out how/ where it would fit on the crank? Any ideas? (P 60 in the SM 47 catalogue)

Thanks

 

[jlaird]

Center of the crank, is a small cutout in the block for them then a cap with one on each side. This is the center main bearing we speeking of, each side of that.

 

[Trevor Jessie]

'76 spitfire engine I think they are in the back main cap.

 

[Morris]

Yes, both sides sit above the rear main cap. If you look at the journal in the block, you will see the groove cut out that the washer halves ride in. You have to slide each washer half around from the under side, then put the end cap on to hold them in place. The grooves on the face of each washer should face outward toward the crank. Put the regular size pieces in first and measure end float. If you have just a bit too much, you can mix one regular size half with one oversized half. If there is alot of end float, use the oversize halves.

 

[JPSmit]

Pistons have a thrust side. This is the right side of the engine.

Right from the front or right from the back - dizzy side or manifold side? (1500)

Thanks

 

[JPSmit]

Yes, both sides sit above the rear main cap. If you look at the journal in the block, you will see the groove cut out that the washer halves ride in. You have to slide each washer half around from the under side, then put the end cap on to hold them in place. The grooves on the face of each washer should face outward toward the crank. Put the regular size pieces in first and measure end float. If you have just a bit too much, you can mix one regular size half with one oversized half. If there is alot of end float, use the oversize halves.

OK I think I found them. Still not quite sure how they are held in but I'll get there. In the meantime, how much is too much endfloat?. I measure that between the crank & the block?

 

[JPSmit]

OK next anxiety - Camshaft. You may recall that I sent the block (1500) out to be measured & cleaned. They did a great job, however, everything came back in boxes with nothing marked before it was dismantled. That's OK, I like puzzles, but, not sure how the camshaft aligns to the crank? I'm pretty sure I can get the cam sprocket back on where it was by the oxidation marks on it. Likewise I can get the sprocket on the crank because of the key. How do I line them up? especially when I don't see timing marks on either sprocket?

I just reviewed the previous cam conversation and it is a little technical for this poor brain.

Thanks
JP

 

[jlaird]

Should be a dot on the cam sprocket and the crank sprocket. I is imparative that these be aligned to each other with the chain on.

Use a straight edge and from center of crank to center of cam shaft they must align. Check it lots of times and have some one else verify it as well.

Be absolutely sure before you button up the front of the engine.

As to your question on crank end float. I have no idea on your engine but you will find it in your manual. No manual? Stop and get one, overnite, but stop till you have one.

 

[JPSmit]

OK, found the manual stuff (I actually have 3) RE: crank end float

Checked the cam sprocket. found a "dot" It's just a metal punch point right?

Still can't find anything on the crank sprocket - any thoughts?

 

[jlaird]

All I have seen have the small dot. Can not think how else to do the job.

Maybe someone else has a comment.

 

[JPSmit]

The rods have noticeably offset bigends and can only be fitted one way to the crank.

Not true - ask me how I know /bcforum/images/%%GRAEMLIN_URL%%/wall.gif however, if they are installed backwards, you can't turn the engine over (which amounts to the same thing I know) On the bright side, everything is quicker the second time /bcforum/images/%%GRAEMLIN_URL%%/blush.gif

Still very anxious about timing since I don't think the sprockets are properly lined up. More on that when I have a minute to measure & reflect. Progress though, pistons in, crank in, cam in, valves springs reloaded. all in all a good day.

(Playing with Midgets is like sex - when it's good it's great, when it's bad it's still good /bcforum/images/%%GRAEMLIN_URL%%/grin.gif )