I have just purchased a new Exhaust Manifold, see pic:
Two points:
First it doesn't fit. The supplier tells me I must grind the edges of the mounting flanges to fit the cylinder head faces.
Second. The diameter of the two orifices at the mounting flanges is 27mm compared with 30mm for my old one - see pic. That's 20% less X-sectional area.
What should the diameter be?
Will 20% less area affect engine performance?
I would send it back, if possible. If you use it and your tractor begins to run not quite right, you will be stuck with it and may spend time and money trying to diagnose an air flow problem caused by the restriction.
Do you mind telling us who sold the manifold to you?
Terry
I bought the manifold from Agriline. To their credit they have offered to exchange it for one which will fit.
I don't mind grinding it, but would prefer one with the correct diameter for the outlet pipes, whatever that is?
In the absence of knowledge on the diameter of the outlet pipes, I plan to measure the size of the exhaust hole in the cylinder head and assume the manifold bores should not be less - is that reasonable? My old manifold is 48 years old so may well have an enlarged internal pipe diameter through corrosion.
Many thanks for your help,
Ben
I would send it back, not so much because the port diameter is small, but because it is a sloppy casting. The port hole on the left side is way off center which means that wall thickness will be all over the place. That can't be good for resistance to cracking. The diameter being smaller is not ideal, but it can be touched up with a grinder, but I would want to start with a nicely centered casting first. Sadly this seems to be the way most reproduction parts seem to be made today. Thin wall casting is an art, and I don't think the guys that made the replacement manifold have the same skill as the people that made the original.
jambug123 wrote:when i got my new manifold (i broke mine in 2 pieces on a branch in the orchard) it bolted straight on with no mods so i would send it back.
Hi Jim,
Where did you buy your exhaust manifold? Do you know who made it?
All,
Many thanks for your advice. I'll send it back.
Thanks,
Ben
When i got mine it was the same as yours , i had to grind it to fit around the combustion chamber plate, it diddnt take much but you have to be careful with it, ihave also got another new one which fitted without grinding , it depends if you are in urgent need of if or if you can do with out for time to send it back etc. the one i had to grind has worked alright for me . Gerry
Aussie Frank wrote:I would send it back, not so much because the port diameter is small, but because it is a sloppy casting. The port hole on the left side is way off center which means that wall thickness will be all over the place. That can't be good for resistance to cracking. The diameter being smaller is not ideal, but it can be touched up with a grinder, but I would want to start with a nicely centered casting first.
As you say left pipe is badly out, as shown by overlaying the gasket in the correct position.
All the best,
Ben
been talking to the chap that runs old 20 parts he says its a common problem with these new cast parts, he scraps alot of parts straight out of the box if they dont look right to save having it sent back!
dexta4 wrote:been talking to the chap that runs old 20 parts he says its a common problem with these new cast parts, he scraps alot of parts straight out of the box if they dont look right to save having it sent back!
My supplier is sending me another; he hasn't asked for the other one back - the photo was enough! Hope the next one is better
All the best,
Ben
Another manifold arrived today to replace the duff one.
The ports align better with the gaskets, as seen in the pic below:
However, it has some quite large channels milled out of it to allow access to the mounting studs and securing nuts. The wall is clearly thinner here and I wonder if it will crack in time?
Unlike the 1st one I got from the supplier, this one is marked AGPO which appears to be a Turkish Co.
It almost fits, a small amount of grinding will be necessary. Agriline tell me that this replacement is from the same supplier as Sparex. Does anyone else have a Sparex one marked AGPO on the bottom?
I guess I'll fit this one and hope for the best.
Ben
Last edited by Bensdexta on Thu Mar 26, 2009 11:47 pm, edited 1 time in total.
Where would you look to find the AGPO name. I replaced my ex. manifold a while ago but can't remember whether the holes were narrower than the original manifold holes. What I did notice was that the silencer flops around quite a bit, that hole is definately too big. I bought my manifold thru Sparex.
Mervyn Spencer wrote:Where would you look to find the AGPO name. I replaced my ex. manifold a while ago but can't remember whether the holes were narrower than the original manifold holes. What I did notice was that the silencer flops around quite a bit, that hole is definately too big. I bought my manifold thru Sparex.Mervyn
Mervyn,
Good to hear from you!
On the one I have AGPO is on the bottom, slightly towards the front of the tractor from the up-pipe.
All the best,
Ben
Thanks for your response. I had a look this morning and did'nt see any name or number. I will email you a pic of mine (fitted) so you can see if there is a difference from yours. I found the invoice for my manifold and I noted it was bought from Sparex. Where our branch here in SA imported it from heaven alone knows.
Mervyn,
I'd be interested to know if your Sparex has substantial channels milled out of the casting to provide access to the fixing studs.
I am getting the impression that Co's like Sparex source their parts from various places as I don't think they make stuff themselves, eg they may buy from a Turkish exporter, who himself has various suppliers. Perhaps this explains why the quality is variable
I have been offered an original manifold off a broken Dexta. Interestingly the holes on this are also quite badly misaligned with the gasket hole, unlike my original Fordson manifold which is spot on - but unfortunately now corroded and split on the up-pipe, so maybe Fordson sourced theirs from various sub-contractors also.
Another difference between the repro manifolds and the original Ford ones is that the repro ones are about 0.5kg heavier. The Ford ones were a finer casting.
I dont believe I had a problem with the gaskets that were supplied, but I definately had to do some filing to the flanges as they seem to extend over the compression caps. The holes did however line up. As I said in an earlier post my only problem seemed to be that the exhaust pipe apiture was sightly larger and the black soot passes past it and make everything black. I have thought of a solution for that but not a priority at this stage. Have to get my mind and enthusiasm going again. Kind of lost interest in the project.
