4-2 Exhaust Manifold Gasket Diameters

AKimball92

AKimball92

True Classic
I purchased a two 4-2 exhaust manifold gasket for my new custom 2-1 downpipe only to find the secondary port diameters are smaller than the manifold I purchased. The manifold port diameters are between 33-35 mm each (slightly oval shape) yet the gasket diameter is 33. I feel this would greatly reduce the gasket life as well as impede exhaust flow. Is there a gasket out there that is bigger in diameter than the 33, preferably 35 or greater?

It appears this one has a smaller bridge between the two but not sure if that is due to misalignment or larger ports.
https://www.ebay.co.uk/itm/Fiat-X19-X1-9-Exhaust-Manifold-Gasket-/201364349089
 
I have pretty much the same question, with a partial answer.

I am making a down-pipe for my 4:2 manifold. I have some leftover mandrel bends/tubes that are 1 5/8", enough to make it from so why not. This is actually a little too big for this engine's needs (they are about 38 mm ID) but not enough to really matter. However with the larger than stock pipes, I was considering a little porting to the manifold to match. But that would make them too big for the gaskets. So I looked for alternatives. In the picture below are two I have.

The one on the left is from a later model Lada; same pattern and thought being a later vehicle it might be bigger ports. But not really, they measure about 34.5 mm. This might work for yours, let me know if you want it.

The one on the right has just under 36 mm ports, so a good choice overall. But I'm not sure where it is from. It was in a box of spare parts that came with a 'parts-car' I picked up. There was the remains of what looks to be a head gasket kit in the box, so I'm guessing it came with that. I like the construction of it; multi layer steel. Just wish I knew where/what its from. The idea of getting one for a later model might still be good, but from a later Fiat (not Lada) like Punto or ?? They might have bigger ports, don't know...maybe one of our Euro members knows.

011.JPG
 
Thanks Jeff, the one on the left is definitely larger than the gasket I have. Where did you get it from? The one on the right does look identical to one easily purchased from our main suppliers but larger ports and what looks to be a black material inside vs. white. I will keep a lookout for one like that as well. I've messaged a few eBay sellers to see what their diameters are.

From the few posts with actual part numbers, it appears my manifold is from either the 1500 Euro X1/9 or a 1600 Punto. I haven't been able to find a good parts distributor for the Punto to know if that manifold design was even on the vehicle. I have not had a chance to dig into it much though.

If you want to get rid of the gasket on the left I will DM you for shipping. Otherwise you are welcome to keep it as a backup.
 
You guys might want to look into the same gasket for early 124 spiders which used a gasket from the manifold to the downpipe. The configuration appears identical to the spider gasket. The boys at Autoricambi can help you out.
 
Perhaps I can help. We have one of these gaskets in stock. See pic below.

It is a Bosal part # 256-749. Bosal is an OEM and aftermarket manufacturer of exhaust parts. Based out of Belgium, but some manufacturing and warehousing in the USA as well. They pulled out of Canada a few years ago.

We have probably had this gasket in stock for a number of years. It is very nicely constructed and quite thick. Outer layers of steel sandwiching some type of composite inner. And "fire rings" - like on a head gasket - around the ports.

Bosal list this for some various Fiat and Lada applications. Yes, we got Ladas up here in Canada for quite a few years.

This particular gasket says "made in Holland". And i can tell from the packaging that it would have come from Bosal in Europe. And would have come through Bosal Canada back then, who would have brought it in from the mother company in Europe. They would usually do this in low volume parts. Sometimes.....on a higher volume part, Bosal USA or Canada would instead source the gasket from a North American gasket supplier. Dont know if they ever did with this particular part #.

Anyway, as you can see from the pic, this particular gasket has an almost 38mm port sizing. Just what you guys are looking for. No...I wont sell this one...but you should be able to find one out there.

A quick google search of "Bosal 256-749" found lots of them for sale on Ebay and from various suppliers, both in North America and Europe. Priced from under $1 to almost $20. Will the one you get be identical to the nice one we have here ? Will it have 38mm ports ? Dunno.....pays your money and take your chances LOL.....

Alternatively.....this same gasket was also made by other companies. One of them was ROL, whom we also dealt with. Strangely - they made this same gasket in two different flavours - one with 33 mm ports under part # EG24543, and one with 38mm ports under part # EG24665. Google those and you can find those as well. Or your local Napa/Carquest/etc. should be able to get, or cross into another supplier.

Good luck. If any of you folks find something, kindly post here. Doug
bosal 256-749 001.JPG
 

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carl said:
You guys might want to look into the same gasket for early 124 spiders which used a gasket from the manifold to the downpipe. The configuration appears identical to the spider gasket. The boys at Autoricambi can help you out.
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No Carl. The gasket for the Fiat 124 looks similar but has a different bolt spacing. I know, we have plenty of those in stock.
 
rx1900 said:
Will the one you get be identical to the nice one we have here ? Will it have 38mm ports ? Dunno.....pays your money and take your chances LOL.....
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Doug, thanks for the part number. I have used plenty of Bosal components for German vehicles and find them to be very good. And I fully agree with your comment (quoted here). It is interesting how the same part number will turn up so many variations of the part, even from the same manufacturer. Not sure if the gasket I have (pictured earlier) is a Bosal, nor what part number it would have been, but it has ports 2mm smaller than the one you have.

AK, I'm sending you a message..check your 'in box'.
 
A quick search of that Bosal part number was interesting.

First, there are two exhaust seals from Bosal with that number. One seems to be a newer application and is a completely different part (a large round ring/donut). I'm wondering if the one Doug has is an older item that may no longer be produced by Bosal? So be sure to see the image for it before buying.

Doug, I assume your eBay search was on Canada eBay? Because pretty much nothing came up on the US eBay. I'll have to look further.

Andrew, here is a little info on that part number:
http://alvadi.ee/en/kataloog/varuosa/12576959/17180?utm_source=alvadi_se&utm_medium=Yellow_link&utm_campaign=Link to alvadi.ee#!tab1
 
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Thanks all, I think I will have to pays the money and takes the chance. a 10 dollar purchase to not impede flow or require modification is easily worth it. I wish the pictures weren't a hand drawn pixelated image. :p I will shop around and find a gasket to order.

Doc Jeff, it looks like this would really help you out as well.
 
Did a little more searching for the Bosal gasket. Doug, I think when you searched you were seeing the other Bosal 256-749, which is the large donut for the '88-'93 Lada Samara 1.5L. Most of the listings do not have an image so looking at the part dimensions helps a little. But the application info is a tip-off (i.e. Samara). The only ones I'm finding like your sample picture are a couple from Europe. Perhaps there were more of them stocked in Canada back then, and might be more available there? But not finding much here. Will keep my eye out though. Thanks again for the info.

Andrew, double check before buying.
 
Jeff - I got about 6 or so hits on Ebay.com (the US site) including this one:
https://www.ebay.com/itm/Bosal-U-S-...1711141643&hash=item2851dc0356:i:173172065110

At $7.76 with free shipping it just might be worth the gamble - if you are from Vegas you must be used to gambling LOL......

This also comes up in a google search:
https://mypartsgarage.com/catalog-2/itemdetail/bosal-exhaust/256-749

Says only $1.99 each . Seems to show "in stock" and seems to indicate free shipping too !!!!

Funny, a google search also brings up images, mostly from Europe. And yeah....shows a gasket of different construction. Tough to tell from the pics what the port size is...but looks somewhat okay. I can tell from the packaging that those images are much newer stock than mine. Kinda makes sense, as that gasket was way more used over there on much later applications than we got here in North America. Quite possibly Bosal had more than one supplier for that part over the years.

But....here in North America, that gasket was not used on many cars that we got here. Yes up here in Canada, mostly on Ladas. And we got lots of them....1500, Nivas, Signets, and Samaras....all that used that gasket.

But in the US, going through all my old Bosal USA catalogs, they only ever listed it for '74 only 128. Although it also should have fit some X1/9, Strada, and Yugo...Bosal USA never figured that out and cataloged for same. Thus i'd bet they never bothered to source them stateside,and just brought them from Europe. And...surely only brought them in back in the 70's and '80s. So any old stock still kicking around in the US would most likely be really old stock like mine......

Ya got the cajones to spend $2 and roll the dice ???
 
After looking at the ones you reference I'm pretty sure they are not the same gasket, but the later donut type that has the same Bosal number. However the ones we seek are available from Europe.

Edit: The one for $2 and free shipping is cheap enough to try "on a gamble" as you say (even though I don't gamble despite living in Vegas) :). But I already found it elsewhere. Thanks again for the part number, that helped to find it from Europe.
 
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Huh ??? Your US google must be giving you totally different results down there ?

Where are you seeing Bosal 256-749 as a donut type gasket ? I see no sign of that at all.... And being Canadian....I know all about donuts LOL.....
 
The referenced eBay listing I see does not have a picture nor any application info, but the dimensions say the part is over an inch thick. So it is either the donut or one REALLY thick gasket. Although the dimensions could be wrong. However the vast majority of hits I get from US sources is for the donut version seal. Same Bosal part number, same description, but for a Lada Samara (different manifold, seal, etc). Here is what that Lada application looks like:
_dsc0308[1].jpg

There might be some listings that are the one we seek, but no pictures, or application info, or dimensions, etc, so difficult to tell. Regardless, as I say I've located the actual (confirmed) ones form a source I've used many times and will be receiving them from there. Your Bosal part number helped me to find them. ;)

P.S. I don't eat donuts so that might be part of the issue for me :D
 
Dr.Jeff said:
However the vast majority of hits I get from US sources is for the donut version seal. Same Bosal part number, same description, but for a Lada :D
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Again....huh ??? Still dont know what you are talking about....Yes, I have googled "Bosal 256-749" and EVERY hit shows the gasket type that I show. I could NOT find a single source that shows it as a donut type gasket.....

Care to give some links that shows the 256-749 as a donut type ??
 
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rx1900 said:
Again....huh ??? Still dont know what you are talking about....Yes, I have googled "Bosal 256-749" and EVERY hit shows the gasket type that I show. I could NOT find a single source that shows it as a donut type gasket.....

Care to give at least one link that shows the 256-749 as a donut type ??
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This is what shows up for me (California):
 

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When using analog part numbers from other manufacturers you run the risk of the part being very different in terms of materials, exact dimensions, quality, etc.. However you also run a similar risk buying the part from the initial maker due to them having various plants around the world, changes in specifications over time, and other variables. So really no guarantee either way. It does help if the supplier gives a detailed description and shows an actual photograph of the exact part that you are buying, but even then you can't be sure it will have the same dimensions/specs you seek. Especially with large parts makers where they supply the same part number to different world markets with vastly different specifications. Bosch is well know for this; just because it came from Bosch with the right part number does not mean it will the same quality or specification you think. And unfortunately price has absolutely no bearing on this, way too much market variance to use that as a gauge (you don't always get what you pay for). Add to all this the fact many sellers are flat-out dishonest about what they sell and the proliferation of counterfeit parts out there, well it is a gamble as Doug says. The best you can do is find a supplier that you know is reliable, with an accurate description/image of the actual part, and accepts returns if you are not satisfied (for larger purchases).
 
ng_randolph said:
This is what shows up for me (California):
Click to expand...

Thanks Bjorn. Yeah, that is pretty much the same google results I get up here. Almost all the images show the proper Fiat flat gasket. Much like the one I have here. But do note, most show a gasket of slightly different construction to mine. So yes, most likely Bosal changed the design at some point, or more likely just bought in the gasket from a different supplier as time went on.

I can assure that my gasket was a Bosal product, and was in a sealed Bosal package before I opened it to take a pic and measure it.

On that page of google images, almost all show that gasket. On those images that show a donut gasket, when you click into the image, it leads you to a different gasket, like 256-992 which is a different Lada gasket.

Perhaps somewhere on the internet, you may find someone who posted an incorrect image of a Bosal 256-749. Mistakes do happen.

But I can assure you, there are certainly not two different gaskets with the same Bosal part #. If you order a Bosal 256-749, and indeed get a Bosal 256-749 in a sealed package,it WILL be the proper Fiat flat gasket. But....I cant guarantee it will have 38mm ports like mine.

I still reckon your best shot is to find an older stock product. And your best shot of that would be in North America where that gasket - unlike europe - was only used many many years ago.

I can certainly understand why most North American sellers dont bother with the hassle of taking a pic of a $2 part. I guess you could contact them and ask for a pic and port measurements, but good luck with that......

Other than that....you pays your money and takes your chances.....Both the listings I linked to are still active, so I guess nobody here has cajones that large. Just for curiosity's sake, I tried to order them, but neither vendor would ship to me in Canada.
 
rx1900 said:
but neither vendor would ship to me in Canada.
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A little off topic, but shipping is always interesting. I've seen many times where a $2 part like this has a $25-50 shipping fee....from within the US. And yet you can buy the same item from the other side of the world, at the same or lower price, with free shipping. Go figure.
 
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