Torque plate with cylinder head valvejob

[ProPower engines]

Some BB Chrysler stuff benefits from a PLATE VJ.
I did some 426 hemi iron stuff a while back that absolutely had to have a T/Plate bolted to the head. The valve seats would distort and not seal without using it.
And Subaru's as well they can be a PITA as mentioned they leak after a short run up if a plate is not used. We played with some V-Tec Honda's that benefited from a T/Plate attached as well.

It can be worth the effort on alot of models but really you will never know till you test.

[statsystems]

Using the right gasket makes sense, but insisting on the actual one is a bridge too far! Better have the plugs torqued and the manifold bolted up too...

I used to be anal about that stuff. I used to mill down a bell housing and torque it on. Same with engine mounts. Then I realized that I couldn't duplicate exactly everything, especially what happens dynamically so I just torque plated stuff and let it go.


You can lose your mind trying to perfect the imperfectable. Especially with limited dollars.

[GARY C]

Using the right gasket makes sense, but insisting on the actual one is a bridge too far! Better have the plugs torqued and the manifold bolted up too...

I was speaking of the block by the way not the valve job, maybe i should be more clear

[kirkwoodken]

Something I used to do was torque the heads with valves (No springs) down to the matching empty block, and check for valve leakage. If they leaked when I sucked on the ports with my mouth, I put lapping compound up from the bottom and work on them until the leaks stopped. Leakers I fixed in this manner ran better than most of the competition way back when. Intakes were/are always most important. I would finish them off with tooth paste or fine paste made from buffing compound. This was done after valves were ground to make sure they didn't leak when bolted together. I never found any consistency to what leaked and what didn't. And yes, many didn't leak. But how do you know without bolting it together? Yes, I know some of you are laughing.

[GARY C]

Using the right gasket makes sense, but insisting on the actual one is a bridge too far! Better have the plugs torqued and the manifold bolted up too...

I used to be [Blank Post] about that stuff. I used to mill down a bell housing and torque it on. Same with engine mounts. Then I realized that I couldn't duplicate exactly everything, especially what happens dynamically so I just torque plated stuff and let it go.


You can lose your mind trying to perfect the imperfectable. Especially with limited dollars.

The only problem I see with tq plate honing with out a gasket of some kind is that you are just bolting a flat piece of metal to a flat piece of metal so although it will address the possibility of the bolts pushing in on the top of the bore it would not simulate any of the distortion you would get from the two surfaces trying to conform to a soft gasket.

[englertracing]

In a perfect world, you would be doing the valve job with the head at operating temp, with the spark plugs in and the torque plates on, with the same type of head gasket you want to run

[MadBill]

And the exhaust valves glowing...

[KnightEngines]

After much cursing & some 'pushing' of the stones I got the seats near as dammit to perfect with the plate on.
Bounce test, NSEW test, vac test & a light lap with some fine lapping paste (that I had to go buy LOL) - all good.

Unbolt the plate & the seal went away - still 'sorta' seals, but down on the vac tester compared to when the plate was still on. I guess that confirms it beyond doubt.

NSEW check with the plate off showed up the biggest difference, was pretty even with the plate one, was on the limit of guide clearance with it off.

We'll leak down test with the heads on the motor & keep an eye on it over the next couple of race meets to see if it holds valve seal longer now.

[rebelrouser]

I have never used a torque plate when grinding seats. But just from pulling engines back apart and checking issues with low hours, it seams that cast iron heads usually hold the seats pretty well, but I have seen several aluminum heads distort the seats from torqueing the heads, especially if they had any extensive porting work done.

[Frankshaft]

I have never used a torque plate when grinding seats. But just from pulling engines back apart and checking issues with low hours, it seams that cast iron heads usually hold the seats pretty well, but I have seen several aluminum heads distort the seats from torqueing the heads, especially if they had any extensive porting work done.

Same here, but it was more of a seat stability issue, from heat stability. Meaning, once the seats took a "set", they stopped moving, and there was no more issue.

[Newold1]

As to Englertracings post about torque plates on GT40 racing heads back in the early sixties, I would guess that aluminum casting technologies and aluminum specifications and materials have gotten a lot better in almost 60 YEARS!!

I think head manufacturers or casting companies today with HIPP ing technology are making heads that stay in shape under more performance demands and uses.

As for Subaru heads I am sure that may be something unique to those head types alone and do not apply to a lot of current V-8 performance heads.
I know nothing about Subaru engines and my head is already overstuffed with the stuff I do know!

[wwmtlineman]

Maybe it doesnt work for all engines but when we ran NHRA stock eliminator with 428 Ford Cobrajets if you didnt do the valve job with a block plate bolted to the head the 2 end exhaust valves would leak. We found this by bolting the plates on a fresh valve job just to see what would happen. We then started doing the valve jobs with the block plates bolted on the heads and the car picked up a bunch. Bear in mind anything that picks up a stocker motor without spending money at all is huge, we arent talking 50 hp here but it does work

[JodyB]

You guys Rock!!! Thanks for all the input!! Gotta admit my question was spurred by one of RW TECH's old posts.Keep it coming!!! Thanks everyone:)

[JodyB]

Anyone care to comment on a "light check" (rotating the valve on the seat looking through the port for visual leakage after machining with no spring?)

[Frankshaft]

Anyone care to comment on a "light check" (rotating the valve on the seat looking through the port for visual leakage after machining with no spring?)

I do that. One of my verification checks, is a bounce test. If it bounces numerous times off the seat, 9 out of 10 times the valve will seal, and has .001 or less runout. But, there could be some chatter, or a low spot, that will leak. A quick visual, if you see no light, you can be fairly confident it will seal. If you rotate the valve, and you see no light, then you see light, your valve is not concentric. This isn't a perfect test, because you really can't see the hidden side of the seat. The best verification test, is a light bump with a fine finish stone. If the seat cleans up 100% with a light bump, its ready to run. If it doesn't, it will show you where its off.