At wits' end

[Reds34]

Guys,

I've been dealing with this engine for almost 10 years now. I'm including a link to my previous post with the issues.

https://www.fordbarn.com/forum/showthread.php?t=142110

For a "quick" synopsis, here is what's happening:

'34 BB truck with a 35 or 36 V8 Babbitt bearing engine in stock configuration.

I was driving the truck going up a slight incline and shortly after I downshifted, the truck started running on 4 cylinders. Come to find out, 2 of the valve guides broke ( I'm assuming) causing the issue with how the truck was running.

I brought the engine to a guy that does mostly race engines (has worked on flatheads before) to have it rebuilt. It took a while (about 3 years) to get it back. He polished the crank, installed new rings, new valves and guides and new gaskets. I got a distributor and carburetor rebuilt (the fuel pump was rebuilt a few years prior). The heads are for dome top pistons, but those are the heads that were on the truck for as long as I can remember. The truck idles poorly with low vacuum. The best way to explain it is that the truck sounds like it has a big race cam in it.

I have done the following things chasing down the issue with this truck:
Tried 2 different distributors with no change with either one.
Tried at least 2 different intake manifolds with no change.
Tried at least 2 different carburetors with no change.
Adjusted the timing on the distributor with no change.

I drove the truck down to the rebuilders so he could hear the truck running. He agreed that it sounded like the truck has a big cam (but it doesn't), or the timing is retarded. He was thinking that the cam may have been off a tooth.

The engine is back at the rebuilders so he can check the timing out. He gave me a call today to let me know that he checked the engine out and everything looks good. He double checked the valve timing and said that it's good. He's at a loss as to what the issue is. He was almost positive that he was going to find that the valve timing was a tooth off.

What do you guys think? I'm at my wits' end here.

Thank you.

Red

[Shoovel]

Did you get a chance to check compression?

[Reds34]

Shoovel,

I haven't checked it recently (in the last year or 2), but I believe that it ranged from 52(ish)psi- 65(ish) psi. I understand this is low, but it has incorrect heads on it currently, and has for as long as I can remember.

Thank you

Red

[Brian]

How did he 'double check' the valve timing? Did he use the split overlap method or just visually check the timing marks [which could be off].
What does a vacuum gauge tell you?

[Brian]

A long shot, but I have experienced it; a leak inside the inlet manifold to the exhaust cross over. Easy check; plug the two heat riser holes and try.

[Reds34]

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Brian,

I'm under the impression that he took the head off and used a dial indicator and degree wheel. He said it was about 9.5 degrees BTDC that the intake opened.

Do you think there would be a problem with 2 separate intake manifolds?

Thank you

Red

[Brian]

OK, valve timing is right, the inlet manifold is aluminum, is it not? Could be cracked internally. What does a vacuum gauge tell you?

[Reds34]

Brian,

The intake manifold is aluminum. The lowest vacuum I've seen was about 14-15"

Red

[richard crow]

have you checked the valve springs they could be weak

[Brian]

Try plugging the heat riser holes [one each side]

[Brian]

sorry, I see you've tried two different manifolds with no change- I'd missed that.

[Reds34]

Richard Crow,

Valve springs are new, although I guess some could be bad.

Brian,

I may do that if we can't find anything else that doesn't add up.

Red

[Brian]

Vacuum is low, but so is compression. Whilst vacuum is low, is it steady, or is it fluctuating? steady low vacuum could be symptomatic of a vacuum leak....I always install inlet manifold gasket with a healthy layer of grease as an aid in sealing.

[Reds34]

Brian,

I wouldn't say it fluctuates, but would call it more of a "flutter". I'm pretty sure that I did a coat of copper spray on the intake gasket when I installed it.

Red

[Brian]

I read your earlier posting in it's entirety. I see you WERE using a cracked manifold. You changed it, but the replacement still could be internally cracked. We now begin the process of elimination... Remove the existing intake, check gasket. If damaged at all, replace with new. Irrespective, coat both sealing surfaces of the gasket with grease. Slip a piece of shim [stainless if possible]over the heat riser holes each side. Leave an 'ear' sticking out each side so you can remove later if required. Torque down the manifold. See how that runs.
Read this; https://www.onallcylinders.com/2015/...gine-problems/

[Reds34]

Brian,

That's good info there, thank you. I pulled out another intake from the stash, is there a good way to check them for cracks? It's just a pain because I'm going to have to put the engine back in the truck to try it. I guess I could just run it on the stand it's on now. Hmm.

Red

[Brian]

Thing is...if the intake has an internal crack, by plugging the heat risers you'll be eliminating the contamination of the intake charge from the exhaust, with the result it'll run.
A few years back I spent literally months trying to figure out why my 35 wouldn't run right. The longer it ran, the rougher it got. I was convinced it was electrical. Finally, in desperation, I removed the manifold and plugged the heat risers. Viola!! what a beautiful thing!!
Now, I don't know if this is your particular problem, but reading through your previous posts, it appears you've done most things. What I am suggesting is easy to do, especially as your engine is on a stand

[Frank Miller]

As the saying goes, spark compression and fuel all at the right time and it runs. I had an issue recently with a Model A. I had put this engine together a number of years ago and suddenly needed it. Got it installed and it ran nice. About 75 miles later it started missing like a bad condenser. We finished the tour we were on but the power was low. Change out condenser and no change. Change spark plugs and it runs like a charm. They did not look fouled but actually looked pretty good so perplexed as to what happened. It's been 600 miles since with no problems.

[FlatheadTed]

The Stromberg carb is made for the early motors if you use a holly or Ford carb on the early manifold it can leak vacuum through the heat riser into the power valve base . Ted

[Ronnieroadster]

You need an engine builder who understands the Ford flathead.V-8. From what I read including your previous posting there's a lot some one who understands how to rebuild a flathead would have done differently than the guy who did this work for you.
Ronnieroadster

[FlatheadTed]

Spark plugs ,Now with the fuel we have or old fuel , Lots of cold starts and minimal driving will put a coating on the plugs that mimics a dizy problem or carb problem ,29 dodge had this, removed the carb fitted a known good model A one, still ran rough ,changed plugs to another new lot ,Bingo .Ted

[Reds34]

Ronnieroadster,

I was actually thinking of contacting you about this issue because you are somewhat close. Maybe I should just pick up the engine and bringing it elsewhere. I totally agree that someone that KNOWS flatheads would have things differently, but hindsight is 20/20. He has mentioned that he does not want to work on flatheads any more.

Guys,

Thank you for all the insight. The plugs are new to the rebuild, but I may try another set.

[tubman]

It may have nothing to do with your problem, but back in my snowmobiling days (2- cycle), we would run into this problem on a regular basis; the plugs would look pristine, but a new set would set everything straight. We'd go over the plugs, clean them and triy to use them, but once they were bad, forget it.

[Ronnieroadster]

Send me PM and I can send you my contact info. I've certainly had my hands in many 21 stud engine's.
Ronnieroadster

[FlatheadTed]

Red s I suggest that your original problem is maybe still there ,by way of the same carb or a switched out one with crud in it cannot see how a broken guide could do that unless it was 80% gone ,you say it runs ok at higher revs , if it smokes out the exhaust then it could be a float issue or if it spits back out the carb then its lean condition ,Vacuum leak (As Brian said ) or dirt ,unless carb is of a good running motor ,get a third carb ,Ted


Qaute
I was driving the truck going up a slight incline and shortly after I downshifted, the truck started running on 4 cylinders. Come to find out, 2 of the valve guides broke ( I'm assuming) causing the issue with how the truck was running.

[Reds34]

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Ronnieroadster,

Thank you, I will send you a PM.

Flathead Ted,

I had the carb (a different one) rebuilt while the engine was getting rebuilt. A fellow Fordbarn member came over with the carb off his '34 pheaton to try with no change.

Red

[FlatheadTed]

I wouldn't think copper spray would be ideal ,I prefer a Gap filler type Goo,OK ,you say it sounds like it has a big Cam ,You can make that behavior by pulling the choke,but you get smoke . Question What happens if you Blip the throttle does it take the Gas or spit back through the carb ,, Ted

[Reds34]

Flathead Ted,

If I blipped the throttle, it would take the gas. I haven't looked down the carb while it was running or while I was giving it throttle, but it never seemed to not take the gas or not take the gas. What kind of gasket "gap filler" do you use on your gaskets?

Thank you guys,

Red

[FlatheadTed]

Gasket Goo, it would depend on how smooth it is people have different choices .I would likely use a silicone base one ,Home depo Clear .at i dial pull the throttle 3/4 up does it rev or hesitate,

[Brian]

My opinion...do not use any of that stuff mentioned above...reason being, you know when you apply that stuff and when you torque down the fastenings, how that stuff squeezes out between the components and gasket?- well it also squeezes out internally into the engine and, if an inlet manifold, into the ports. How much has gone into the engine? who know's? but it's in there.
Now, if you follow my advice and use grease, you'll witness the same phenomenon; squeezing out of the joint. Thing is though, any grease that squeezes into the engine is easily assimilated into the engine oil or fuel air mixture and cause no harm. Additionally, it allows the surfaces, as they're bolted down, to slide across the gasket faces. Grease forms a perfect seal, also, eases disassembly and most times even allows the gasket to be re-used.
My opinion, take it for what it's worth.

[FlatheadTed]

Nothing wrong with grease ,The main thing is you find out whats wrong with your Motor .I saw Brian trying to help so I hope I didn't interfere . Ted

[tubman]

I will admit that, when it comes to gaskets, I am a "greaser" and have avoided fancy sealers (except for leaking head studs and bolts) since I became one and hae done very well.

[aussie merc]

i think this needs to be pulled apart but i wouldnt be surprised to find the valve stem seals damaged you know them little cows on the outside of the guides ..when they leak they leak bigtime and can be near impossible find

[Karl]

Originally Posted by tubman

I will admit that, when it comes to gaskets, I am a "greaser" and have avoided fancy sealers (except for leaking head studs and bolts) since I became one and hae done very well.

I agree -The only time Iuse the goop is if I'm bolting together wildly out of whack surfaces For example i used a bit of it when I reassembled my 1910 Hupmobile engine . After 111 years nothing fitted together with close tolerance and the goop gave us a good seal with out the risk of breaking something as we torqued it up. I could have remachined each surface but with zero spare parts and old castings I prefered not to take the risk of machining anything