351C low oil pressure when hot

[mudder460]

I am buying a 1972 351C with 2v heads and a 4bbl intake for $200. The guy told me that when the engine gets hot it has low oil pressure. He told me it runs find with no problems just the low pressure. What would cause the pressure to drop when it gets hot? Also could I throw in new rod and crank bearings without machining anything? Thanks!

[hollenjoe]

low preasure means bad bearings, etc, if its not consuming any oil and compression is good on every cylinder, the new bearings will get your oil preasure up and keep you going a little more, you will only have to reground your crank which is cheap and measure it for your new bearings....

You might wanna check your heads also, and maybe rebuilt them, that will almost cover a good build up

[mudder460]

Ok, I am on a very tight budget. So should I have crank turned for the rods or mains?

[smokeyb97]

Originally Posted by mudder460

I am buying a 1972 351C with 2v heads and a 4bbl intake for $200. The guy told me that when the engine gets hot it has low oil pressure. He told me it runs find with no problems just the low pressure. What would cause the pressure to drop when it gets hot? Also could I throw in new rod and crank bearings without machining anything? Thanks!

I just had my engine rebuilt because of low oil pressure particularly at idle after warm-up. The rod and main bearings looked fine, but the cam bearings were shot. This engine had over 204,000 miles though.

[85e150six4mtod]

When you tear it down, have the crank measured and inspected. "Bad" bearings, well, OK, how about "worn" bearings. The bearing material is very soft compared to the crank, so your crank may be fine. As for turning mains or rods, depends on the measurements.

Did he say what the oil pressure was? Some people think all is lost when they see 20 psi at hot idle. 10 psi per 1000 rpm is a good rule.

This going in a truck? Sure about the "C"? Sure it will fit your bell? (it has SBF bell, not the 385 pattern as found on 351M)

Good luck with it.

[mudder460]

Yeah, it is going in my truck in my sig. I have the 300 now, so it will fit. I am new to these motors but you can run 351m headers on here right?

[mudder460]

Here are a few quick pics, will get more tomorrow.

[85e150six4mtod]

Originally Posted by mudder460

Yeah, it is going in my truck in my sig. I have the 300 now, so it will fit. I am new to these motors but you can run 351m headers on here right?

Not sure. The deck on a 351M is just under 2" higher than the C, so that may or may not work in your favor......

[mark a.]

Thet sure would sit a lot lower if they didn't hit anywhere. Did they have a mechanical gage on it ? The factory gage sender can do that when it goes bad.

[johnboy427]

Most 351M/400 headers hit the starter on the 351C due to the lower deck height. You can dent some with a hammer to get them to fit. I did mine that way but the collectors set so low the exhaust had to go under the transmission cross member, which I don't like so I am looking for other options. The motor in the pic almost looks like a 4V motor to me the intake gasket does for sure, if you are trying to run a factory 4V intake on 2V heads don't it will never run right you will be better off with a 2V than the port mismatch. It could just be the light but that ports in the gasket just look big.
-Johnboy

[hollenjoe]

Yep that defenitivley is a 4v intake, but in the picture, the intke ports in the heads look ported to match the intake, which will suck later if you are changing it to a 2v aluminium one...

[mudder460]

Well that is the intake the guy was running on the truck. So I am thinking it is a 4V after all, this ports do look big now that you said something. My parents are going to take some pics of it tonight and I told them to send me pics of the casting numbers.

As for what gauge he had hooked up to it, I am unsure. I will just pull the crank out anyways and have it checked just to be safe.

[mudder460]

Alright, so I finally got some pics of the motor and it is a 2v, verified by the 2 on the heads. I emailed the po owner about him running the 4v intake and he said he did run it like that. The told me the po before him did do some porting to the head. I am thinking it would be better just to get a stok 2v intake and put it back on? I will upload the pics to my photobucket account later an and post a link, this way you guys that know what you are looking for can check it out. my parents couldn't find any casting numbers on the block, then again they don't really know what to look for. I do have a question and I am sure it is about a 1 in a million, but how common are Aussie blocks?

[hollenjoe]

I was right on my post then, thats what i ment " the intke ports in the heads look ported to match the intake, which will suck later if you are changing it to a 2v aluminium one..."

you will better stick on using 4v intakes, and the one you have seams like a good choice, keep it...

[300 Buster]

You have the potential for good engine there,why not bite the bullet and do right by it.First off,Ford's oil pumps of that era were not great,that may even be the reason for bearing wear,replace it with a high volume Melling or equivilant,send the block out to be hot tanked,cam bearings replaced,mains line bored and deck checked and bore checked.Measure the rod and main journals on the crank,if they are in spec and round ,just polish,if not regrind and check the rods and so on,build it the way you want it.These engines are going away and they aren't coming back.I have heard that the 4V intake with 2V heads with the ports done were a good for low end torque,something to do with increased velocity?At any rate,at least invest in a good oil pump,and have your crank checked and ground if needed,that way the bottom end is good to go.The 351M and the 400 weren't Fords greatest acheivments,but the Cleveland wasn't bad and they are getting thinned out.