[SD455DJ]

Originally Posted by north

The 400-340 is not mentioned in the 69 shop manual or the early printings of the brochures but its covered in bulletins. I guess they figured there was a gap to fill between the 400-290 2bbl and the 428-360 4 bbl. It was priced accordingly at $47.39 versus $105.32 for the base 428. I'd imagine that the 70 prices for those upgrades were a bit higher since most models of the Cat-Exec lines were downgraded to a 2bbl 350-255.

In 69 the 400-340 was only offered with automatic while the 400-290 and the 428-360 could be had with manual trans (3 on the tree only), was that also the case in 70?

North - Yep, the same in 1970. 400 4-bbl 330 hp only available with TH400 on B-bodies (Catalina, Ventura, & Executive).

Dennis

[SD455DJ]

...and the 400 cu. in. 2-bbl 10.0:1 compression 290 hp was available with 3-on-the-tree, or TH400 like in '69.

[north]

So the only real difference than from 69 was that both the 2 and 4 bbl 400 dropped compression from 10.5 to 10.0?

[SD455DJ]

Yes, essentially, and the 428 grew to become a 455, however, where the 360 hp 428 was available with a 3-on-the-tree manual (and got the bigger valve heads, etc.), the YH 455 (small valve #15 heads) was auto only.

Dennis

[north]

I actually have a 360-428 horse manual engine. Unlike the automatic 360 horse engine this one is basically an automatic HO without the manifolds; it has 4 bolt mains, 067 cam, large valve 62 heads.

Can’t have been many of these engines produced.

[SD455DJ]

North, What are your plans for that 428 Those are great engines!

[north]

That's the engine that has given me troubles, I've got it sitting on a pallet at the moment. It was a virgin WG (62 heads) engine when I bought it. When rebuilding it I swapped in a 455 crank and new pistons to net me 9.5 compression, otherwise I left it stock.

It ran nice (mild stock equivalent cam, stock valvejob, distributor and Qjet). But at 400 miles (all of it easy cruising with a TH400 and 3.08 axle) it developed a knock so I stopped driving it immediately.

We opened it up and the cam bearings were chewed up and one rod bearing was beginning to wear.

My engine shop never did figure out what went wrong (I suspect that the cam to bearing clearance was off spec). All bearings were replaced and when it was restarted the second time it ran fine but had an odd oil pressure issue so I pulled it out again. Oil pressure issue is as follows: cold idle, hot idle, high RPM everything is fine (factory gauges but I also tested with a mechanical gauge and had identical results). Problem is between about 2,200 and 2,500; below that or above that engine runs at 60-65psi as expected but at 2,200 it suddenly drops to 45, rev it a bit and around 2,500 it suddenly jumps back to 60-65. This happens regardless of load, identical effect in gear or in neutral.

Now 45 psi is obviously plenty but given the previous failure you have to wonder what the heck is going on here? I've given up on my engine shop (not the first problem; every second engine has had to come out in recent years).

Maybe a defective oil pump (its a melling stock replacement)? I'm trying to find a good experienced Pontiac specialist that is within decent driving range of Montreal (say NYC or 3-400 miles).

[SD455DJ]

North - That is weird. I wonder if it is a drain-back issue of the oil staying in the heads too long for some reason, causing a low level in the pan at that certain rpm range. I know it doesn't seem to happen above or below that window. I wonder if it could it be the oil pump as you mention. That would be a good experiment to try a new pump and see what it does. The oil could be cavitating in the pump housing. Did you blueprint the pump by chance before installing it?

Dennis

[north]

I don't know if the rebuilder went through the pump. My gut tells me its the pump, especially since 2,200 is about when you hit full pressure and the pressure release ball kicks in, maybe it's sticking?

The problem is I've lost faith in my rebuilder and given that the cam bearings failed last time I'm hesitant to put it back in again. One thing for sure is that I want a new rebuilder to go through everything first. I also want a shop that has a engine dyno so the engine can be tested before installing it in the car.

My concern is that this oil pressure anomaly may be a separate problem from whatever chewed up my cam bearings. I'd hate to put it back in (for the third time) and have it knocking again in a tankful or two.

The Bonneville it comes from has every imaginable option (AC, power steering, power brakes, cruise, Instant Aire pump, power disc brakes, automatic leveler, long branch etc) so it takes hours and hours every time I need to pull or install the engine. Not to mention every engine in or out is another chance to scratch an expensive paint job.

[SD455DJ]

North, I think you are on to something with the check ball and spring acting up when the pressure peaks and unseats the ball. I'd change the pump...it seems something internally wasn't machined right.

The only person I trust is my brother Dan when it comes to rebuilding a Pontiac. He's built many a fine running pure stock Pontiac and is rebuilding the 428 HO from his '68 Cat at the moment. Knowledgeable Pontiac engine is a rare and valuable commodity in the sea of Chebby bellybutton shops.

Dennis

[CDN2PLS2]

He did mine!

[north]

Btw, my apologies to kmeyer54, I have a bad habit of hijacking threads! Don’t mean to do it.

[SD455DJ]

Originally Posted by CDN2PLS2

He did mine!

That's right...and ready for the car when Scott get's done!

Dan's building 2 - 455HO's and 3 - 428HO's at the moment. The 455HO from my GT-37 is next in line after these...so probably next year, haha.

kmeyer54 - Any more progress on the Catalina?

Dennis

[kmeyer54]

Apologies for the delay in response, and no worries about the brief derailment! I'm all for the sharing of information even if it's only tangentially related to the thread. Life has been busy lately, but I was able to remove the timing chain cover and I've mostly gotten it cleaned up and ready to be put back on. Anyone have a good source or maybe an Ames part number for the crank seal mentioned earlier? For some reason I'm having some difficulty finding the right part. I still have one of the broken off bolts to get out, which I'm going to attempt to do tonight. So far the threads seem to be in good shape, so at this point I'm planning on keeping the original cover. I just need the seal and a gasket set for the timing chain cover before I can begin re-assembly. The original radiator also still seems to be in acceptable condition, so as long as the heat problems are resolved I intend to keep it at least for the time being.

[Stuart]

Most any auto parts store should be able to supply the timing chain cover seal, I just checked Auto Zone's website as an example and they have a couple different ones available.

[kmeyer54]

Turns out that last bolt in the cover just isn't coming out, so today I ordered a new cover, a gasket set, and a can of Duplicolor DE1616 Pontiac Metallic Blue. Originally I was planning on painting the new parts, but given the rough appearance of the block I'm tempted to just reassemble it without painting the parts. It seems like it would look just as out of place to have the water pump and the timing cover freshly painted when the rest of the engine looks worn. Thoughts? Tips on properly painting these parts as well as applying the gaskets in the most effective way possible are appreciated.

[SD455DJ]

kmeyer54 - If you plan on power-washing and detailing the engine compartment, then paint the cover and water pump. If not, I would just leave them natural. As for the gaskets, clean and whip the mating surfaces with a solvent, then apply your sealant sparingly, let it set up for few minutes then assembly. Too much sealant would/could eventually break off inside the cover and drop into the oil pan and potentially end up in the oil pump screen.

Good luck and cant wait to hear you are driving and enjoying your Cat!

Dennis

[Stuart]

You have to clean the engine well, remove various brackets and things, and do a good job of masking off everything that doesn't get painted, but it is possible to do a decent job of painting the whole engine while it's still in the car. That's what I'd do.

[SIX8YAK]

I for one enjoyed the entire story of your acquisition. As has been said, you don't see these things anymore and it looks to be in good shape!

I have a 68 Grand Prix, around the same rareness, that is patiently waiting to hit the streets again. Gotta keep these boats on the road!

[kmeyer54]

Well, today was extremely disheartening. I finally got all the parts I needed to finish replacing the water pump and timing cover, and worked almost non-stop from 3 PM until 1 AM getting everything done. I was finally able to start the car, only to have the alternator dummy light on and then a squeaking noise developed from somewhere in the general vicinity of the new water pump. I can't even be sure if it's coming from the water pump, because the pump is right in the middle of about a dozen other components that could theoretically make the same sound. It seems to my untrained ear that its idling higher than usual, and to top it off when I got out of the car and went to close the garage I noticed that it had dumped large quantities of ATF from the radiator amd another spot under either the motor or the transmission. I'm really not even sure where to go from here at this point.