• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

1500 Head Job

Share this page

C

capitalcitycars

Jedi Trainee
Offline
Hello all! After taking a year off from the girl to build a garage, I'm back to her and I need to do a head job due to a leak. Any tips for a first timer on this? Should I do the valves as well? What about roller rockers? Any advice would be most appreciated! Thanks!
 
Brian,

First off, I know squat.

But if it were me, I'd take it to a recommended shop with a photocopy of the specs and see what they say about the springs and valves. At the least they would take a minimum shave off the head and give it back to you totally cleaned and ready for re-install.

I'd also give some serious thought to replacing the existing low compression pistons to the now standard high compression. This would be a Good Thing all round - more performance and runnning more efficiently. Of course this would invove dropping the oil pan/sump and getting under the car to remove the con rods etc.

Cheers,
Adrian
 
Pick up a copy of David Vizard's book on Performance tuning the A series engine. Much of the information will relate to your 1500 engine. If you are going to do the head, valves are an integral part as well. Roller rocker arms are an excellent upgrade depending on your budget. Refreshing your OEM rocker arms would be a great economical choice as well. Where is the head leaking? Valves or surface to surface? If you think it is a coolant leak you will want to have the head Magnafluxed to pinpoint any potential cracks in the water jackets. I just finished a head for my 1275 and it made a huge difference in performance.
 
The leak is surface to surface and I was planning to have it magnafluxed. Lansing has no shortage of machine shops. The rockers are definitely looking like an option and the pistons are definitely worth thinking about. I already have a new/remanufactured distributor and planning to upgrade the plugs & wires as well.
 
If you're taking it apart anyway, be sure to check thrust washers. They're easy to change. Just drop the pan and pull one main bearing cap. Rod bearing are a related weak spot in these engines......if you have the pan off anyway, it's a cheap and simple job to put in new ones
If you've gone this far, it's not a bad idea to pull the pistons, hone the bores and re-ring it, but that's up to you.
Be sure to have the valves ground. If any of the exhaust valves are marginal, replace them....they're pretty cheap A valve job on an older engine tends to boost compression and exploit weak rings....that's why I'd look at the rings while you're at it. Be sure to plane the head if you've had gasket problems. Don't worry about taking too much off...these heads have plenty of "meat". You can take over 0.100" if you want (but I would not take off more than needed on a street engine or you may boost compression too high for normal street gas).
Roller rockers look neat but you don't absolutely need them for street use. My 1500 racer has stock rockers with 6 years of racing and about 60K street miles and they're fine.
 
I'm almost certain that all '76's have hardened valves and unleaded heads - so they may not be as necessary. Do change the thrust bearings though - cheap insurance
 
Thank you for this info which is not in my Haynes manual! Can all this be done without removing the engine? I don't have a lift.
 
If you do end up rebuilding your valve train... I bought my parts for the job at spitbits.com. Got good parts and saved a few $$s.
 
I had blowby issues last summer, and did a 'quickie' hone, rod bearing replacement, HG and head skim, port & polish and valve stem seals on my 1500.

https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/483918/1

https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/475350/1

FWIW, if I were going to do it again, if there was anything to do on the bottom end (rod or main bearings, hone, skim, etc.) I would PULL THE ENGINE!(it's not worth the hassle, to try to do it in the car. And they're simple to pull. $40 for an engine hoist rental, or $29 for a cheapie chain fall from Harbor Freight, is worth the money.

On the HEAD side, you can check for play in the valves, to see if you need new guides. Similarly, play in the rocker assembly should be easy enough to determine. New rocker arms and/or a new rod are all readily available new. You should be able to clean up and reuse your valves. Your machine shop can tell you whether you need a valve job. (I ended up just cleaning and lapping in my old ones.) As Nial mentioned, you can have the head skimmed to your heart's content, and never worry about taking too much off.

Now, opinions on this may differ, but I installed viton stem seals.

headrebuild002.jpg


These weren't installed stock from the factory, probably as a cost-cutting measure... which is probably why these engines have the reputation of smoking on the over-run, even at relatively low mileages. They were a perfect fit, simply push onto the top of the valve stem. Bought directly on eBay, search "viton triumph" or something similar and you should probably find them easily.

If you're feeling adventurous, you can always get out the Dremel, and smooth any casting marks on the runners (leaving the inlet side fairly rough, and polishing the outlet side as smooth as possible).

On the BLOCK - If your engine stays in the car, I'd stick to rod and thrust bearings, assuming they haven't been done recently.

If the engine comes out, assuming for the moment that your bores look OK, and that you're still running the stock head and pistons, I would do the following.

- main and rod bearings, thrust bearings
- hone bores (easy, can be done at home with 3-stone hone)
- STD. flat-top pistons (bump compression from ~8:1 to ~9.5:1)

The only other thing that springs to mind is... when you get your rocker ass'y off, pull a couple of the cam followers out. Depending on whether the previous owners have been negligent in their oil changing, you may find that they are heavily pitted (mine were). If so, you'll need to budget for replacement of them, and possibly the cam itself.


Phew! OK, I hope that made sense...
 
Thank god to this day I havent had anything happen to have to pull my 1500 engine. Knock on wood. But I am curious as to how long it actually takes to get it unbolted and out of the car? Could 2 guys lift it out if you didnt have a cherry picker?
 
Before I worried about roller rocker arms, I'd do the basics, repalce valves if needed, hardened exhaust valve seat inserts, new guides if needed, new springs if needed. Fiquire what pistons you going to use in the rebuild, deck the head for desired compression ratio.

About the only choice for roller rocker arms for 1500 is Harland Sharp, and all you get form them is 8 roller rocker arms, so you need new adjustment hardware, you may need customlength pushrods, make some soild spacer, it's a pretty good chore, alot more to than just sliding them on a shaft, oh did I menetion they will need to be reamed or hone to fit the sahft, it fairly good job to make it work. I'm willing to bet most of the HS roller rocker sold on Ebay are sitting on the shelves in folk' garages when they realize what a job it is to make it all work. Here's a set of HS roller rocker arms on a 12785, it took me all day to get it all wroked out and I do this for a living :smile:
 

Attachments

  • 16345.jpg
    16345.jpg
    45.2 KB · Views: 213
You can get a perfectly adequate lift crane from Harbor Freight for about $100, and they go on sale pretty often. I've seem similar ones for similar prices from Pep Boys and such. Nice to have around, too; I've found all kinds of uses for mine. Frankly, if you're going to do a lot of work on the engine, it probably is easier just to pull the thing. Takes a couple of hours; maybe a bit longer first time you do it.

If you're just going to do the head, you don't need to pull the engine, of course.

My only words of wisdom echo Hap's: it's awfully easy to get sucked into a big, expensive project, so do the basic stuff first. Things like roller rockers are fine as part of a project to do major performance upgrades, but I doubt they'll do much by themselves. Frankly, I think a valid approach is to do the head properly, put it back together, and see where you are. If you decide to do more later, you're only out a gasket set.
 
RE: Viton Valve Guide Seals

I have read several posts from Spit guys cautioning against the use of valve guide seals claiming that in some cases it can cause a stuck valve. I don't have a strong opinion one way or another, but I just wanted to throw it out in case you want to investigate further for yourself.
 
Just FYI:

My 1500 racer with 10:5 compression and Euro-spec cam burns <span style="text-decoration: underline"><span style="font-weight: bold">no</span></span> oil even after a 4 Hour Enduro.
That's mostly at 5500 RPM+ with endless upshifts and downshifts.

It has no <span style="text-decoration: underline">real</span> valve seals. Just those little "0-rings" on the valve stem.
 
Midget78 said:
Thank god to this day I havent had anything happen to have to pull my 1500 engine. Knock on wood. But I am curious as to how long it actually takes to get it unbolted and out of the car? Could 2 guys lift it out if you didnt have a cherry picker?
Click to expand...

theoretically I suppose but it's WAY easier to pull with transmission and I think with two guys there might be tears wen something gets dropped/ dinged
 
Thanks for all the advice! I have plenty to chew on.

BTW: My friend and I have lifted the engine without a hoist before but that was with the body panels off & it was quite a chore! It took 2 hrs to get the engine in and we were laid up the next day. I don't recommend it.
 
Back
Top