TR2/3/3A Checking a cylinder head with a straight edge to see if it's warped?

[karls59tr]

What size feeler gauge is correct to see if it will slide under the straightedge?..... .002 or .003 or ???

 

[bobhustead]

If a feeler gauge will fit, the straight edge or the head is not flat. You don't know if your straight edge is straight in any case. Have it assessed by a machinist and shaved if needed. Or, you can just go back and do it all again soon.
Bob

 

[mctriumph]

Karl, just go and have your head shaved !!
Mad dog

 

[karls59tr]

Bob What I meant to say was What size feeler gauge "should I attempt to slide" between the straight edge and head surface. And I am a backyard mechanic and proud of it. I have successfully kept my TR3 on the road doing my own repairs for 20 years. A .003 feeler gauge did not go under the "straight" straightedge and the head appears fine to me.

 

[karls59tr]

Karl, just go and have your head shaved !!
Mad dog

I'm not ready for the Yul Brenner look yet.

 

[charlie74]

I have read that a bright light behind a straight edge will tell you as much as a feeler gauge but I have never done it myself. Whenever I have had my head off it went to a machinist based on advice I had been given. Maybe a TR6 head has a greater tendency to warp due to increased length…?

 

[mctriumph]

Karl , I dont know if I could rock the Yul Brenner look either, Still, after having done my
first valve job in 1969, I always made certain with a quick shave, It will appease the headgasket
Gods if nothing else. I am still batting 1000 (knock on wood).
Mad dog

 

[karls59tr]

I guess my thinking is if I'm going to take the cylinder head to a machinist I may as well get a valve job done if I'm going to take everything apart. But the valves do not look burnt and the head liner protrusions are OK and the head appears to be flat so I may as well try a new head gasket and see what happens. If the motor runs OK great....if it turns out that the FO8 gaskets are the issue then I'll have to dig deeper and replace the liners at that point and do the head then.

 

[JHaydon]

I am really surprised that the Triumph shop manual (and even the Triumph competition tuning guide) makes no mention at all of even checking the head for straightness, much less an allowable amount of warpage. I wonder how many warped heads have been reinstalled over the years??

I am turning to my engine building books for the Ford 1600 engine (also a pushrod 4, though I think physically a little longer than the TR engine). The definitive FF1600 racing engine book simply assumes that the cylinder head will be resurfaced any time it is freshened (not necessarily every time it is removed). A much older race engine building manual says much the same. The most authoritative book on 1600cc Ford street engines says

"I am not going to lay down how much clearance is too much. It depends on how far you are going in your power tuning. For top power on a racing or rally engine, any clearance is too much, and having the head and block refaced is almost mandatory.
...
"The decision becomes more difficult if you are just overhauling the engine... I have overhauled engines with up to .003 or .004 in warping between the head and block without having any long-term problems. As a general counsel, if you are having the block rebored, have the block and head checked and, if necessary, refaced as well."

Maybe the reason that nobody specifies a number is that a warpage of 0.002" from one extreme end of the head to the other extreme end is a little different than 0.002" of warpage from one side of the head to the other?

 

[malbaby]

Be aware that your cyl head may have been shaved previously.....check thickness before any shaving.

 

[karls59tr]

Be aware that your cyl head may have been shaved previously.....check thickness before any shaving.

It has been shaved before . What's the proper procedure to check thickness?

 

[CJD]

With american cars, .005" is max, but they do not depend on .003" liner protrusion to seal the combustion chambers.

There are 2 schools of thought. I favor the, ""while going to the trouble of taking apart the entire engine, you might as well make it like new", school. The other school says, "if it meets the service limits, then it's good enough." If you follow the latter, just realize you may have it back apart sooner than later.

 

[mctriumph]

Checking the cc's of one of the chambers is the best way to get to compression ratio. Piece of plastic
with a small hole, fill the chamber with a syringe. Good to know with todays fuels.
Mad dog

 

[malbaby]

Plus one for checking chamber volume to determine compression ratio.

 

[CJD]

Well, we are having trouble convincing Karl to shave the head and pull the sleeves...does anyone really think he is going to get into blueprinting, LOL?

 

[bobhustead]

Some are more concerned about the reported cracks around a head stud.
Bob

 

[karls59tr]

Some are more concerned about the reported cracks around a head stud.
Bob

The hairline cracks have been there for 20 years when the head was first installed after the bottom end of the motor and cylinder head was rebuilt. A friend of mine,a diesel mechanic, was helping me install the cylinder head. Prior to installing the head he inserted the head studs into the block but instead of tightening down finger tight he must have mistakenly over tightened them or as mentioned before someone must have tried to lift the head by the end bolts. At any rate I pointed out to him that there were hairline cracks at the last two rear studs. At this point getting a new head or doing a repair was not an option. So we applied an orange type of sealer (cant remember the name of the product} and proceeded to torque down the head. Now I have driven the car for over 20 years with no issue from this repair. The car has always performed flawlessly. So when I recently pulled the head evidence of the sealant was still there and there was no evidence of a coolant leak in that area. I do remember when I pulled the head this time it seemed to me that the center head bolt nuts seemed easier to remove than at the other studs so I believe that over time they had loosened causing a gasket leak there. There was no evidence of a blown or damaged gasket in that location or anywhere but I believe the leak did occur there from the loose head bolts. In retrospect I should have just re torqued the head and did a compression check. The odd thing is there was no coolant in any of the cylinders. I'm going to install a new head gasket and retorque the head and do a compression check, which I should have done in the first place. If the compression is good I'll run the motor. If I get coolant in the oil again I will be reasonably sure the problem is an FO8 gasket. At that point I'll pull the head and remove the liners deal with that issue and get the head shaved as well. Another reason for doing it this way is that the cylinder walls and valves appear undamaged.

 

[karls59tr]

Well, we are having trouble convincing Karl to shave the head and pull the sleeves...does anyone really think he is going to get into blueprinting, LOL?

I am going to get the head shaved but not until after I find out if I have to go through all the hassle of a major FO8 repair. So I have to pull the head twice big f**king deal.

 

[CJD]

"I am going to get the head shaved but not until after I find out if I have to go through all the hassle of a major FO8 repair. So I have to pull the head twice big f**king deal."

Sorry Karl...comment not meant as much for you as for the guys trying to get you to cc the heads. You are a minimalist, and I truly respect that.
My favorite mechanics are the ones who can cross the country in a jalape, and fix literally anything with a screw driver and the wife's hairpin! My OCD won't allow me to ever accomplish that.

 

[karls59tr]

It's OK John. Sometimes I get triggered when I feel I'm not understood but I've always appreciated your solid advice. My apologies for over reacting.