TR4/4A What is trickiest part of engine rebuild?

[tdskip]

Good discussion in details with KVH on his effort. What do you all think the hardest/trickiest part of a TR4 engine rebuild is? Beside paying for it of course, ha.

 

[TR3driver]

None of it is particularly hard, IMO, tho it's a little tricky getting the cam bearing inserts lined up just so. Dressing the oil pan flange back to flat (from where the DPO/DCO overtightened the bolts) can be a pain too.

 

[tdskip]

Hi Randall, thanks for the response and hope you are well.

Do you have anyone local you trust on block/head work if needed in SoCal?

 

[TR3driver]

Do you have anyone local you trust on block/head work if needed in SoCal?

Sorry, not really. I've used KK&T in Torrance and been happy with them, but that was a long time ago. Don't know if they still have the same machinist or not.

 

[KVH]

Dressing the oil pan flange back to flat (from where the DPO/DCO overtightened the bolts) can be a pain too.

I'm spending all day on exactly that. No matter what I do, some other dimension is then bent, distorted or offset. Whacking those high spot bolt holes only goes so far. I suspect someone once had a great time wrenching the pan off the gasket bound edges with a screwdriver.

 

[2wrench]

The trickiest part of an engine rebuild, in my humble opinion, is garnering the patience. I got out my Big Mouth Billy Bass this morning, as I realized my scope of work has been expanded. He sings: "Don't Worry, Be Happy." I'll play this until I can't hear it anymore, pull the batteries and place him on the shelf again. For now.....I'll listen.

 

[tdskip]

Ha - good point Dennis.

i don't have any schedule to be on, and as my first engine work on planning on going slow and enjoying the experience.

 

[Tr6easyrider]

I'm spending all day on exactly that. No matter what I do, some other dimension is then bent, distorted or offset. Whacking those high spot bolt holes only goes so far. I suspect someone once had a great time wrenching the pan off the gasket bound edges with a screwdriver.

When you are ready to install the pan and the timing cover, use 5/16 flat washers under the lock washer and bolt.
That helps to distribute the pressure, however minute, and minimize the dimpling of the holes.
Joe

 

[tdskip]

Good tip Joe

 

[Darwin]

Trickiest part is keeping everything spotless and organized. Clean twice assemble once. Check everything before tou touch it.

 

[glemon]

I still remember the mistake I made when I did my first rebuild, which was TR 4 cylinder. Found out the con rod's eccentricity allows them to be installed either way, but only one way allows the motor to turn a full rotation, nothing in the books I had at the time mentioned this or provided any guidance. Figured it out before I had it all buttoned up but not right away.

Agree with the comment about patience, also if something doesn't feel right going on or resistance to hand rotation goes up you have a problem you need to fix. Work slow check your work both physically on the car and with the shop manual frequently as you go.

 

[sqbsprite]

In my opinion it's balance. It makes a huge difference in the finished engine and it's something that is very difficult to do accurately yourself. My last rebuild was several years ago on a 1275 A series. I took all the parts to a friend who builds race engines and let him balance the rods, pistons, crank, and flywheel. The end result was so much better than my attempt on a MGB engine. The MGB always had a rough spot at 3500 rpms. The Sprite on the other hand is smooth as silk all the way to 6000.

 

[tdskip]

Steve, couldn't I have a machine shop do that or do we all think that new piston/liner from Moss etc would be good enough for a street car?

 

[sqbsprite]

Definitely ask the machine shop to do it if they can. Many shops will focus on getting the tolerances right but they don't have the right equipment or expertise to do the balancing. It takes patience to get it right. I'm not sure what you will see in weight variation between the new pistons. I wish I could give you specifics, but I don't know the details. That is why I left it to an expert.

 

[tdskip]

Thanks Steve

 

[PatGalvin]

Hey Tom
Any of the machine shops that work on British engines should be able to check all the parts and tolerances for you and advise you as to what you need to buy. I tore down my engine and brought them all the parts in a box. They cleaned them up and told me what I needed (i.e., oversized bearings, connecting rod piston pin bushings, etc.). They will check the crankshaft mains and ensure you don't need an align bore (or is that line bore?). They will check the big end of the rods and verify round and to spec. Or they can resize those big ends and make them new again. I am so surprised at how smooth my engine is, right up to 5K rpm. They did a great job balancing it. Bring them the flywheel and pressure plate so they can balance everything together. Also, don't forget the crank pully or nose piece (if your engine has that). I'd bring them the clunky fan too, if it is the nice aluminum TR3 model. They can balance everything. My total machine shop bill was about $1,600 and they did everything I needed to start assembling. Now those are Sacramento prices, which will be high for many of the other states and probably a bit less than SoCal.

They found a defect in one of my connecting rods and told me to get a new one. I bought two new single rods (two purchases) from Ebay and each weighed in so differently than my original rods, they couldn't make them work. I ended up buying a set of four used rods and changing them all out in order to make it work.

Keep posting questions and progress. Engine building can be a lot of fun.