Trailrunner

So, I recently picked up a 67 Toronado and I'm still trying to wrap my mind around what I actually have... The motor has the number 389244D near the water pump. After searching on this great site I know it is a 425. But which 425? It isn't painted the Toro color at all. It appears to be gold with one of the valve covers painted dark blue. So...I remove the alternator to see what number was stamped on the front of the passenger head. There doesn't appear to be anything stamped there (see picture). Any ideas? I know there are some very knowledgeable folks here and I appreciate the info.

Ross

MDchanic

Try the back side of the LH head. If the heads have been off, they may have been swapped.

- Eric

joe_padavano

The D-block 425 is a 1966-67 block. B heads were used in 1966, C heads in 1967. Your motor appears to have been at least partially apart at one time, and it wouldn't be surprising if the heads were off for a valve job. Paint can be changed at any time. As Eric noted, while you would think it would be 50-50 on getting the heads back on the same sides, it seems more like 90-10 that they get swapped during reinstallation. No big deal. The blue valve cover is likely a newer replacement for one that got mashed in the valve job.

Trailrunner

You guys were spot on! So...on the rear of the driver side head, my daughter with her young eyes (mine are old) read to me R078890T. Again, this is a 67 Toro. I know from reading on this forum that I can't know for sure if it is the original motor. Can someone confirm if this is at least the correct motor? BTW - I would never have thought of the heads being swapped so I sure thank you. Does seem strange that nothing is the slate blue except the dual snorkel air cleaner.

Ross

MDchanic

R######T is a 10.5:1 Toro motor head.

Sounds likely that you've got an original Toro motor there.

Only way to be sure is to rip it apart, but if it runs well, just use it as-is.

One thing I would say is that since you know that the heads have been off, if it seems to run well on modern gas without pinging, without the timing being waaay retarded, someone may have installed thick head gasket shims back in the late '70s - early '80s to lower the compression ratio to 8-9:1.
If that's the case, you're in luck, as the modification may have saved the engine from destruction on 1982-vintage 87-octane premium.
Since you know the heads have been off already, there's nothing to lose by pulling them again to check the gaskets (and the piston dish). You'll lose about a half a point of compression by using modern 0.046" Fel-Pro-type gaskets when you re-install, instead of the original factory 0.016" steel gaskets, but the thicker gaskets will bring the compression back down to 9.75 to 10.0:1, which is much safer with modern fuel.

- Eric

EightballZ

sorry for my (maybe) dumb question....but if you do a compression test...can you tell from the PSI reading which CR that engine has?

MDchanic

Nope.

First of all, if the motor was opened in the past, other things may have been changed, such as the camshaft, and different camshafts will show different dynamic compression numbers.

Second, the measured cranking compression will depend greatly on how quickly the engine is cranking over, so will be influenced by the condition and model of starter motor, as wel as by the condition of the battery and the wires.

In general, higher-compression motors will have higher cranking compressions, but there are no precise numbers for the results, so you can't be sure.

- Eric

J-(Chicago)

A more accurate estimation would be achieved by pulling one of the spark plugs out and looking into the hole to see what the pistons look like. Also, note how thick the head gasket appears to be.

After market low compression pistons will have a big dish in them like this:
http://i298.photobucket.com/albums/m...lockgasket.jpg

Stock high compression pistons will have a very small/shallow dish like this:
http://i638.photobucket.com/albums/u...IMG_0732-1.jpg

Octania

EASY

Toronado 425's have this here DRILL SPOT on the fat rib adjacent to the base of the oil fill tube.

I thought this was now common knowledge...

Help spread the word...

4040_66-To-425_CN6-1.jpg


PS the similarly 0.921 liftered E 400 blocks also share this feature.

MDchanic

True, and I will admit I had forgotten that - I'd filed it away under "How to tell if it's got the big lifters," - but clearly it also works to tell whether the motor came with 10.5:1 pistons, too.

HOWEVER, in this case, since his engine has been opened up and painted a different color, the question is not whether it came with Toro pistons, because it looks like it did, but whether someone had had it apart for a rebuild and changed the pistons, and if so, to what. That's a harder question to answer without a direct inspection.

- Eric