TR4/4A Yet another engine build thread. Parts list: Suggestions/Recommendations/Etc

[ghawk16]

So I'm in the process of restoring my Triumph TR4 and will be rebuilding the engine myself. I'm looking for any guidance on parts and what to get and what not to get from the start. The motor only has 88k and change on it and it ran somewhat fine when it last was run in 2006. Talking with my pops he mentioned some potential issues with valve seats or something to that extent. But here is a list of parts and what I'm planning to do and I want some input.I'm planning to get most my stuff from BPNW as they seem to have a good reputation on parts and have, what it seems, everything I need to rebuild. So any input you can offer is appreciated. Thanks I also plan on updating this thread as I go along. I do have a workshop manual so I'll be going off that for the specs unless some other spec is required for the part I'm putting in.

1. 87mm Piston and Liner Kit (BPNW)
2. Performance Camshaft 270 (BPNW)
3. Tri-Metal Connecting Rod Bearing STD (BPNW) - I notice different types (010,020,030,040). How would I know which one to buy?
4. Thrust Washer Set (BPNW) - Guessing get the STD size and if I need a different size for the back (or was it front?) for the float either buy the one I need here or go custom from Scott Helms?
5. Timing Chain and Tensioner - If my chain is fine, do I need to replace this? I've read OE is always better if it's in good shape, but always good to replace tensioner?
6. Bronze Valve Guide Set 3/8 to 5/16 Conversion - Is this conversion worth it? I know valve guides should be replaced, but...
7. 5/16 Large Stainless Exhaust Valve (BPNW) - See above...worth it?
8. 5/16 Large Stainless Intake Valve (BPNW) - Again, worth to replace with new.
9. Valve Spring Set - BPNW - Leave original or replace since I'm going new with other items?
10. Valve Caps
11. Head Gasket Set-Big Bore (BPNW) - Goes with the 87mm Piston and Liner Kit
12. Copper Figure 8 Gaskets (BPNW)
13. Cam Bearing Set (BPNW)
14. Lower Gasket Set - Payen (BPNW)
15. Main Bearing Set - STD (BPNW) - Again, notice there are 010, 020, 030, 040. Do I measure what I pull out and go with that thickness?
16. ARP Head Bolt Kit (BPNW) - Necessary? This is a why not since I'm in there. I think the head has been pulled once before, but not sure.

Missing anything? I'm sure I am. I'm planning to have the crank, flywheel (lightened), PP, pulley, etc balanced. I'm going to send the distributor out to Advanced and have them put a Pertronix and make sure it's all dialed in. Going to just run normal SU's. Would it be good to have the head skimmed or the any kind of porting done? I'm thinking that's a waste on such a small engine. I'm looking at going with a header system, but wasn't sure HOW MUCH of a difference that would really make compared to the stock header. I know the later headers provide better flow, but want the outside of the engine to look fairly stock for my model year. What about porting the early exhaust mani a little? I don't know how thick the walls are. Anyway...I think I've rambled on enough, but I hope I can get some good feedback before ordering these parts. Thanks again and cheers!

 

[Rut]

I'm just starting on my 4a and I've built a couple of MGB engines and I'm working on a 1275 for my Bugeye Sprite. Acme Speed Shop (Hap Waldrop) put together my rebuild kits from a variety of manufacturers, choosing the best components from each. The cost was less than what I would pay at BP Northwest since he provides a discount (uses BPNW for a lot of parts) and makes sure the components work well together to give me the best bang for the $. The unique part is that he provides tear down info for assessing your needs, advice before, during, and after the build to get you the performance you want, and a machine shop check list to make sure you get what you need there as well. I couldn't be happier with my engines and will be using Hap for my TR4a. He's an MGB racer and builds engines for track and performance street cars. Give him a call and you'll be happy you did.
Rut
https://www.acmespeedshop.com

 

[malbaby]

As above, have an experienced workshop build your engine.
Although the TR engine is relatively simple, there are so many things that can be overlooked and go amiss.
Not worth the risk.

 

[TR-3rg]

Hi,

I would suggest hardened valve seats with the head work. Changing the valve size is probably big bucks compared to the power gain on a street engine. It might not give you the best bang for the buck as mentioned above. I had the rods on mine magnafluxed at the oil hole. Get Kastners books if you do not already have them, he goes over stuff like that. As far as changing the compression ratio, cam, porting and exhaust, have a conversation first with a knowledgeable Triumph engine builder or cam grinder. I went with a 4 tube header and installed an O2 sensor on my TR-3. It makes the tuning real easy. BTW, I have a 10 pound aluminum flywheel and its great.

Good luck and keep posting the progress,

Roy

 

[Graze]

Other simple things to consider

Check water pump, consider headers (called extractors here), get pistons and rods balanced, lighter flywheel, get crank crack tested

Good luck with the build

Graze

 

[MichaelG]

Here are several ancillary things to consider..sometimes the little things can make a big difference

Check the oil pump clearances carefully and rebuilt if necessary.

Distributor rebuild by Advanced distributors is inexpensive, it's got to be worn if never serviced.

Vent the crankcase by installing a vent tube and oil catch can...

Send the Rocker assembly to [FONT=arial, sans-serif]Rocker Arm Specialists...repair as needed.

Upgrade the rear main oil seal

Have the radiator checked by a radiator shop

Good luck with the rebuild[/FONT]

 

[ghawk16]

Thanks all for the tips and recommendations. I've seen some things listed by others that I forgot to mention that will be done, such as:
1. Radiator flushed, tested and repaired as needed. I believe there are some holes up top on the neck from shoddy welding. Also, the bottom may be dented. Does anyone have pics of the bottom of the radiator from a TR4 and what it's supposed to look like?
2. Will be upgrading water pump to 6 blade.
3. Upgraded RMS to Vitol from TRF
4. Pistons and Rods will be balanced with crank and other items.
5. Hardened valve seats (hence if I was going to do that, why not go with the different valves. But I'm not sold on replacing those if they are in good condition)
6. Block and Crank will be tested for cracks and any other deficiencies
7. FW will be lightened and balanced
8. Oil pump cleaned and checked of tolerances
9. Distributor serviced (mentioned in original post)


I know some people have said to take it to a shop, but I believe I can tackle this. I've built quite a few Audi S4 motors with the 2.7 Twin Turbo V6 and that was more of a drag than this. I do like the idea that Rut mentioned of talking to a shop that knows what works with what and what doesn't. So I will definitely give Acme a call. I'm not going for any speed records so if just a 87mm piston/sleeve kit and camshaft is all it takes to get a little more grunt then I'm fine with that. The shop doing my body work also has an engine builder on staff that is willing to help and answer any questions I might have so that's at my disposal. Just want to make sure I'm not missing anything. Thanks again all!

 

[TomMull]

I know some people have said to take it to a shop, but I believe I can tackle this.

For what it's worth, cam bearings can be tricky, but several have done it: https://www.britishcarforum.com/bcf/showthread.php?70894-Cam-Bearing-Install-TR4
I send mine to the machine shop, get the bearings installed and block professionally cleaned to boot. I also have the machine shop do the balancing and head work. I do have a trustworthy, reasonable machine shop that I have been using for many years and I am extremely pleased with their results.
Tom

 

[charleyf]

Before you buy the rod and main bearings you need a professional to look at the crankshaft . They will either polish it or grind it to .010, .020 or whatever is needed. That will determine what bearings you need to buy / use. Another option is to get the crankshaft nitrated ( hardened). I would guess most people will not recommend this extra step unless you are going to subject the engine to racing or high stress use.
one more item is the upper bushing on each of the rods.
Charley

 

[TR-3rg]

Hi, When you are checking out the oil pump, make sure it has a pin between the shaft and the rotor. If the engine was rebuilt in the 1970's, 80's it might not. The pumps with only a pressed on shaft/rotor (not pinned) have been reported to fail. I replaced the one in mine with one that was pinned. Don't forget a good fuel pump and filters.

Roy

 

[JerryVV]

Don't use bronze valve guides, stay with the stock cast iron guides. Many have stuck valves using bronze. You need more clearance than most shops feel comfortable using. No real gain with bronze.

 

[Rut]

Don't use bronze valve guides, stay with the stock cast iron guides. Many have stuck valves using bronze. You need more clearance than most shops feel comfortable using. No real gain with bronze.

Bronze is great if the clearance is correct. A lot of shops now sleeve cast iron valve guides with bronze liners so you get the best of both worlds.
Rut