• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR6 TR6 valve help/upgrade?

Share this page

I

ichthos

Darth Vader
Country flag
Offline
I need more help... again. After working on my car for a year, I was finally able to enjoy driving it for the past year (thanks to help from many of you on the forum.) Even though it runs, my car still runs poorly. Today I finally broke down and went to a mechanic locally that specializes in British cars to ask his opinion. When I explained how it was running, he said that I more than likely need to rebuild the carbs and also have the valves adjusted. He also said that my car just wasn't meant to be run on the new types of fuel, and that the only way to not have to be continually be adjusting the valves is to do a valve upgrade. This is where I need help from you. It is my understanding that the old leaded fuel used tetraethyllead as an octane booster. Why would the byproduct, lead, have any effect on the valves postively or negatively? If an upgrade is a good idea, what exaclty am I talking about? Is it something a nonmechanic could do, or is it just more cost effective to have a mechanic do it? I have so many things I am doing on this car, I know I need to let some things go and yet keep the $ under control. If you could, please remember I am a novice and to keep things simple.
Thanks, Kevin
 
Kevin,

In addition to raising the effective octane, the TEL also formed a coating on surfaces in the combustion chamber. Among other things, this coating helped prevent the exhaust valve seats from eroding, due to micro-welding with the (very hot) valve heads after every exhaust stroke. When lead started being phased out, the valves and valve seats were upgraded (hardened) so they no longer needed the TEL to prevent erosion.

However, in many cases, the coating left from previous running on leaded fuel will last a long, long time; possibly for the life of the engine. And adjusting the valves is routine maintenance; relatively easy to learn to do, and requires a minimum of tools.

So, my (and many experts who know better than I do) advice is to learn to adjust the valves yourself, and keep an eye on them. If you find that the exhaust valves (valve seat recession only affects exhaust valves) are routinely too tight after only a few thousand miles of driving; then you will know you have a problem and can start saving for a valve job. It does absolutely no harm to "wait and see", since the parts that are being damaged are exactly the same parts that have to be replaced to do the upgrade.

The upgrade itself is not a job for a novice, IMO. Depending on how much you want to learn, you can do the majority of the 'grunt' work yourself by removing the cylinder head from the engine. But after that, I would suggest taking the head to an automotive machine shop to have the actual work done. They will use an assortment of expensive special tools to mill out the old exhaust seats (which are part of the cylinder head casting) and press new hardened seats into place; then machine the seats to accurately match the (new) valve heads. They will also replace valve guides as needed (more special tools); and check whether the valve springs need to be replaced (good chance they do). They should also check the head for flatness, and machine it flat if necessary.

You can call around for prices, but I would guess that a complete valve job on a 6-cyl head would run something like $400-$600 with parts. This is very standard work for auto machine shops; so you don't necessarily need to find one that specializes in British cars.

On the carb rebuilding; there are many different levels of "rebuild". Most commonly, they just need to be cleaned thoroughly and have a few parts replaced (seals, diaphragm, gaskets, etc.), then adjustments made. This is something a novice can easily learn to do, using common hand tools and a few relatively inexpensive special tools. Poke around on this forum a bit; I think someone recently posted a link to a good series of articles on the web showing exactly how to do the carb rebuild. If not, send me a PM with your email address; and I'll forward the articles to you in PDF form.
 
If your TR6 was made in 1974 or later it was ment to run on no-lead fuels. Older TR6's were made to run on gasoline that contained lead. The lead when burned in the combustion chamber left a deposit that lubricated the valve. I think the frequency of adjusting the valves is not related to the type of gasoline but a function of how they are designed and made. The VW (air cooled) motors required frequent adjustments along with many other motors.

I wonder if roller rockers reduce the required frequency for adjusting the valves? If it does, you may be greatly advantage to install a set and receive less noise and some performance improvement as a by product rather than a valve up grade. BTW what is a valve up grade?
 
vettedog72 said:
I wonder if roller rockers reduce the required frequency for adjusting the valves?
Click to expand...
No reason they should. Certainly won't help solve valve seat recession.
vettedog72 said:
If it does, you may be greatly advantage to install a set and receive less noise and some performance improvement as a by product rather than a valve up grade.
Click to expand...
IMO, roller rockers are only useful in combination with a wild cam. Unless you change the cam, the difference in performance will not be enough to even measure, let alone make them cost-effective. And rollers bring their own set of problems.
vettedog72 said:
BTW what is a valve up grade?
Click to expand...
The most important part is replacing the exhaust seats with specially hardened seats. In most cases, the valves are replaced too.
 
I concur, I have had my TR6 for 3 years and no problem with Hi test gas and valve recession,I adjusted the valves once. Now if you go to that trouble pulling the head, you might consider milling the head and porting, and CC the chambers,,,etc My understanding thats where the power comes from, I know someone on the forum just had their head gone over,,,
 
What year is your car?

As some others have stated. After 74 no worry. I would consider another viewpoint referral(2nd Doctor's opinion) before you go to the trouble of pulling the head.

Get someone to give it a good electrical tune up. Make sure the coil is good, Make sure the breaker plate ground strap is good. Make sure the timing controls are functional. A valve adjustment is a fairly simple maintenance that I would recommend you learn to do. Number one, it will give you a starting point on the shape of the cars seats, as another poster stated watch the gap changes). Carburetors, I would lean more toward.
Make sure the diaphragms, linkage and bypass valves and air filters are in good shape.
 
hondo402000 said:
Now if you go to that trouble pulling the head, you might consider milling the head and porting, and CC the chambers,,,etc My understanding thats where the power comes from, I know someone on the forum just had their head gone over,,,
Click to expand...


They call that Brosky-syndrome.
 
Thanks for all the information. It gives me some optimism since I do not have the $1,000 or so to get the work done by someone else right now. My car is a 69, so it looks I may need to be concerned about the lead. I guess the consensus so far would be to adjust the valves and watch what happens about every three thousand miles. If I do decide to get the head rebuilt, what specifically would I need to ask to have done? How does one know whether the valves need to be adjusted in the first place? I admit that adjusting the valves is one thing I never did before getting this to run. I have a Bentley manual so I will make an attempt. I can not find the gap in my Bentley, but my Haynes says .010inches 0.25MM) - does this sound correct?

As far as the carbs go, I would love to learn how to rebuild them. All I did so far was to clean them and make sure the diphragms were not torn. Rebuilding would be convenient since I have an extra set of carbs, but there are a number of reasons I have not attempted to rebuild them. For one, kits seem to be expensive and if I mess up, I'll have to pay for a rebuild in addition to the parts. Also, even though I can struggle through directions, I am not able to distinguish a bad from a good carb rebuild kit. I don't recall anything good being said about the big three as far as kits go. Does someone know of a good source for a rebuild kit? And the last thing that is making me hesitant is that if this is so easy to do, why do they charge $600-$800 to rebuild them?

Kevin
 
Hi Kevin,

Researching for my rebuild I had some lengthy conversations with people like Ted Schumacher of TSI and others with much experience with these cars and other old cars from the lead era and the cylinder heads.

The long and short of it is something like this.

The original intake valves and cast in head seats are good as long as they have not been ground excessively already.

It is a good idea to replace the exhaust valves with SS or stellite valves. If the seats have not already been ground or only a small amount removed and they look good keep them. Otherwise replace them with hardened seats. The seats in these heads were induction hardened during manufacture but that hardened surface is not very deep so once ground through it is gone.

Also replacing the valve guides is a good idea.

Anything else would be by choice or by necessity.

Oh, Brosky says that some guy in LA started all this. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

I broke in my cam and lifters today and have an appointment to get my exhaust done tomorrow. Change oil and put the interior back in and I will be on the road all weekend.
 
.010" is good (assuming you have a stock cam).

I'm too lazy to go find my TR6 owner's handbook at the moment, but it gives an interval and procedure for checking the valves. Basically, you turn the engine until the lifter is on the base circle (meaning the valve lash is as large as it gets), then stick a feeler gauge between the rocker and the valve stem. Takes a bit of practice to learn the feel of "just right" (but fortunately it's not all that critical); a .010" feeler should pass through with some resistance, while a .008" feeler should have no resistance at all and a .012" should be very tight (if you can get it in at all).

My preference for LBC parts source is The Roadster Factory; as the owner, Charles Runyon is a genuine Triumph enthusiast. But I may not be entirely impartial. And he's not the best businessman in the world, which shows sometimes.
https://www.the-roadster-factory.com/

BTW, they have reprints of the TR6 owner's manual on sale at the moment. ISTR the 69 version was $13.

For $600-$800; they should do things that the normal DIY mechanic does not do, like replacing the throttle shaft & the bushings it runs in. It does also take a fair amount of time to do the work, even though it's not terribly difficult, and the time adds up when charging $60-$80 per hour (which is a reasonable rate).
 
It was that guy who keeps whispering, cam, rollers, new pistons, aluminum flywheel, etc.

Yes, he's a Doc and from Cajun country!
 
Hello Kevin,

a lot of good advice, but no one has mentioned that your style of driving is a big factor. If you don't do a lot of miles and drive 'steadily' then you could well do many years motoring before the head is too bad to get by with adjusting valves.

I'm in the UK and have a 1972 P.I. engine, tweaked a little, regularly run to 6,000 rpm and cruise at 3,500 ish on an unleaded head but with a fuel additive. I've done nearly 40,000 miles on that engine with minimal valve adjustment required.
By the way, my understanding that head work, unlike many engines, doesn't release a lot of power.

Alec
 
Okay, you've got a very good parts source not far from you. BP Northwest. They back their stuff up and their prices are very good.

As far as needing valves.?

If you can find an older shop that has, knows how to use and can use his oscilloscope take it there. They should do a cranking compression test(electronically killing one cylinder at a time) telling you if you have a weak cylinder which would be the direction to direct your work at. Power output test, etc. They also should be able to do a good electrical tuneup, making sure the advance is working, plug wires good, plugs, etc... Also a good scope/dyno man can use the scope to balance the carbs.

A major area of wear on these engines, is valve guide wear. They will wear, just a matter of mileage and time. When you replace them get the good ones that you can have valve stem seals put on, and at that time exhaust valve upgrade and seats if needed. But if you're lucky something you won't have to do for a while.
 
RonMacPherson said:
A major area of wear on these engines, is valve guide wear.
Click to expand...
I don't disagree that they wear; but it's not what I'd call a major problem. These engines will run just fine with the guides badly worn, they just burn more oil and blow blue puffs when you shift. Unless the valves are leaking badly (which you can find for yourself without having to pay someone to use a 'scope), no sense tearing down just to change the guides.

I drove an engine in my TR3A for awhile that had horribly worn guides, so bad that I had to stick seals on them to cut the oil burning. (Literally got a warning from AQMD for excessive tailpipe smoke.) I've still got the speeding ticket I got with that engine, showing 92 mph ...
 
Agreed, Can be run for quite awhile with oil sucking past the guides. I was advising for WHEN he decides to rebuild the head.

Heck, I'm from the days of umbrella valve seals and spark plug extenders so the oiled plugs would fire. Thing is he was mentioning about getting the car "smooth" running.
 
Randall,

Where in sunny SoCal are you? When I lived in Orange County(moved over from Rancho Santa Margarita). There used to be a very well stocked dismantler down in Huntington Beach near the industrial park(river). Wonder if he's still in business.
 
Hmm, are you perhaps thinking of Albert Roth in Manhattan Beach ? Or possibly John Nichols in Gardena ? I don't recall ever hearing of anyone in HB that specialized in LBCs (but of course there are dismantlers all over the place). I've even picked up LBC parts in "Pick Your Part" in Wilmington in the past. They are still there, but it's been a long time since I've seen a Triumph in their yard (and I don't go nearly as often now that I have more money than time instead of the other way around /bcforum/images/%%GRAEMLIN_URL%%/smile.gif )

I live in LA county, near Long Beach.
 
Back
Top