8 RT Heads
 

The engine in my 51 F1 has 8RT heads is this correct and what does the 8 RT mean? I couldn't get a history of the motor when I bought it.
Thanks!

Re: 8 RT Heads
 

Yes, the 8RT heads are correct.They have a different compression ratio than 8BA heads. They were used on all trucks from 48-53 in the F-1 thru F-6 series.

Barry

50 F-1

Re: 8 RT Heads
 

RT=regular truck

Re: 8 RT Heads
 

8=1948, R=Rouge, as in Rouge plant, T=Truck. As Barry stated, different compression, read lower. Common misconception that the late (8BA) flathead came out in 49.

Not to argue with Barry, but I have a January '52 Truck Chassis Parts Manual that lists the parts number for 48-51 heads as 8BA and 52 (& 53) as 8RT.

Re: 8 RT Heads
 

Other than the heads what differnece is there between the 8RT and the 8BA engines. The 47 I brought home Saturday has 8BA heads. I know the 8BA was not used until 48 so the engine was likely replaced. Parting it out anyway, but always needing to learn more. Rod

Re: 8 RT Heads
 

The 8RT had either a 7RT carb or 8RT, the difference being a hand throttle. The choke bracket was huskier on the 7RT in contrast to the smaller 8BA bracket. The oil pan has a rear sump with a large cut out on the 8RT. It also has a different starter plate and dust shield. And, of course the bell housing is different. The 8RTs had a cast iron ring(not to be confused with the Mercury stamped steel ring), for lack of better words, that bolted to the block (what you hear people call an adaptor when talking about bolting a newer manual transmission to the 8BA); the 8BA had a rather conventional-looking bell. Last, but not least, the water pumps for the 48-52 trucks had a foot cast onto them as the front engine mount. 53 trucks used the car-style pumps as the front mount was a horseshoe-looking affair. Otherwise, the basic engine is the same!

Re: 8 RT Heads
 

a lot of the 8RT blocks had factory relieving , that was supposed to give the engine more power by letting the engine breath better by letting the incoming air charge have a shorter path into the cylinder, but i dont think so, what you gained doing that you lost because of even lower compression ratio by removing the metal

Re: 8 RT Heads
 

I have heard of the earlier truck engines having this, but am unaware of this in the 8RTs. Not saying they didn't, but keep in mind that the 8RT went in everything from the F-1 (not likely to need "extra" performance) to the heavy load-carrying F6. Since the engines were externally identical, with perhaps an added goveror, it would seem a hassle to keep track of relieved and unrelieved engines as they were shipped out. I have a 19,000 mile 8RT engine that is decidedly not relieved.

Re: 8 RT Heads
 

I don't believe I've ever seen a late block that was factory relieved.

Re: 8 RT Heads
 

Thanks guys! I always learn something from you.
Stu

Re: 8 RT Heads
 

If you read the 48-54 parts books, it shows 8BA heads for 48-51, but were superceded to the 8RT heads, so technically both are correct for the 48-51 years, but 8RT only for 52-53 years. I put 8RT heads on mine, as they were nicer looking than the 8BA heads that were on my engine which came out of a 51 F-2. Alot of the 8RT engines were worn out by the early 60's, and were replaced with 8BA engines from cars. I mis-read my parts book. I stand corrected.

Barry

50 F-1

Re: 8 RT Heads
 

The 8RT & 8CM cylinder heads have the lowesr CR of all the OEM heads.

Re: 8 RT Heads
 

If R stands for Rouge plant.
Is there other Truck engine's that come from other plants?

Like 8XT

Or was all truck engines built at the Rouge plant?

Re: 8 RT Heads
 

No, all truck engines from 48 to 53 were 8RT, excluding the 337 cid Lincoln that resided in the F-7, F-8

Re: 8 RT Heads
 

Don't be misled by assuming that the parts book tells you what parts were on a truck(car) when manufactured. The parts book lists REPLACEMENT parts.

Re: 8 RT Heads
 

You're right, but being in the Ford parts business for many years, I have an understanding of thier ( Ford's )mentality. It looks like the 8BA heads were out first and were on the truck and car engines in the USA, until the 8RT head was offered on production, Then, Ford realized that the 8BA/8RT heads were so similar, they superceded to the 8RT head, THey still do it today. WE have 2 p/s hoses for 94-95 Ford F-series w/diesels and the 2 are identical right down to the sealing rings. THey list them as being different, but either will work in each situation. I will concede that being such along period of time has elapsed. As far as the books are concerned and unless someone has a rare closeup photo of an assembly line engine, It would be safe to say it;s ok to use either head and be correct. A superceded part is still the correct part for that situation.

Barry

50 F-1

Re: 8 RT Heads
 

Obviously not something you could positively hang your hat on, but there are two F6 firetrucks on ebay right now. One is a 1950 with 8,7XX original miles and 8BA heads, the other is a 1948 with 11,XXX miles and 8BA heads. Both engines have traces of red paint still visible on the engines. The chance of both low mile trucks having replacement heads/engines would have to be low. Not a closeup of an assembly line engine, but probably the next best thing.

Re: 8 RT Heads
 

I just got myself a flathead out of a 51' f1 and the heads are 8BA and Im surebthey are factory. Bellhousing and pumps are 8RT

Re: 8 RT Heads
 

Typically these low mileage fire trucks have had multiple engine rebuilds or replacement engines as although the truck is “low mileage” the engine also drives the water pump for extinguishing fires and have thousands of hours running time working hard. Mileage on a fire truck is zero reflection of the engine.

OOPS THIS IS A THREAD FROM 2010.

Re: 8 RT Heads
 

I had a '48 Seagrave pumper. The truck had 2400 "road" miles but a lot more hours on the pump hour meter (I seem to remember 23,000). Anyway, the engine (a Pierce-Arrow derived V12), was in fine shape.